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Hydrostatic Pressure-Induced Spectral Variation of Reichardt’s Dye: A Polarity/Pressure Dual Indicator

Cite this: ACS Omega 2020, 5, 1, 897–903
Publication Date (Web):December 26, 2019
https://doi.org/10.1021/acsomega.9b03880
Copyright © 2019 American Chemical Society
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Abstract

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The famous solvatochromic Reichardt’s dye was applied to quantify hydrostatic pressure in media. The UV/vis spectra of the dye in various organic solvents are shifted bathochromically or hypsochromically at the shorter- or longer-wavelength band, respectively, upon hydrostatic pressurization. The ET value, determined by an absorption maximum, in ethyl acetate increases from 38.5 kcal mol–1 at 0.1 MPa to 39.2 kcal mol–1 at 300 MPa, which is mostly equal to the one in chloroform at 0.1 MPa. These spectroscopic origins were supported by the time-dependent density functional theory (TD-DFT) calculations. The concept and approach proposed in this paper, i.e., a dual indicator, should attract the attention of a broad spectrum in multidisciplinary science.

1. Introduction

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Chemical indicators are a type of sensor that outputs a spectral, optical, or electrochemical signal in response to a chemical input to be quantitatively determined.(1) For instance, a pH indicator is a well-known example used to colorimetrically analyze pH in solution, where proton concentration and UV/vis spectral changes are the input and output information, respectively.(2) Such chemical indicators serve as versatile chemosensors for sensing, probing, and imaging a wide range of analytes such as chemicals,(3) volatile organic compounds (VOC),(4) explosives,(5) chiralities,(6) biomolecules,(7) and apoptosis for cancer treatments.(8) Among the many dyes/chromophores/luminophores reported so far,(3−8) a colorimetric indicator that can measure media conditions (e.g., polarity, viscosity, and polarizability) is critical for basic science as this makes it possible to more easily elucidate details about solvent–solute interactions. These weak interactions, i.e., solvation, are inherently considered to be one of the entropy-related factors controlling not only supramolecular complexation equilibria in the ground state,(9) on the basis of eq 1, but also photoreaction rates in the excited state.(10)(1)(2)Here K represents an equilibrium constant, R is the gas constant, T is the temperature, P is the pressure, ΔH° is the standard enthalpy, ΔS° is the standard entropy, ΔF° is the Helmholtz energy, and ΔV° is the change of volume.
According to eq 2 derived from the common thermodynamic parameters, the pressure term turns out to be a fundamental controllable factor.(10b,11) Indeed, the effect of hydrostatic pressure on molecular recognition in solutions have long been investigated,(12) and greatly affect volume changes upon complexation. These facts indicate that simultaneously measuring pressure as well as polarity in reaction medium can lead to a deeper mechanistic understanding of the origins controlling chemical reactions. Although various pressure-responsive luminophores in solutions have been developed over the years,(13) a dual chemometric indicator that is susceptible to mutually related polarity and pressure is quite rare.
Reichardt’s dye (1), shown in Figure 1, has long been known as a useful solvatochromic reagent, and generally, an empirical ET value estimated from an absorption maximum in a solvent is now widely employed.(14) This prompted us to develop a novel dual indicator that exhibits drastic UV/vis spectral changes in response to hydrostatic pressure stimuli as well as solvent polarity.

Figure 1

Figure 1. Chemical structure of Reichardt’s dye (1) and definitions of the angles τi.

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In the present study, to expand the range of 1 from the original to the dual indicator, we investigated the hydrostatic pressure effects on compound 1 in common organic solvents with its spectral variation upon hydrostatic pressurization and also examined the origins of the spectral changes by means of quantum mechanical calculations. The results will be discussed to elucidate the factors governing the hydrostatic pressure outcomes of 1.

2. Results and Discussion

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The hydrostatic pressure effects on the absorption properties of dilute solutions of compound 1 were first examined in ethyl acetate, chloroform, dichloromethane, acetone, acetonitrile, 2-propanol, ethanol, and methanol as representative eight organic solvents (ET; 38.1–55.4 kcal mol–1) using UV/vis spectroscopy. As shown in Figure 2, a broad intramolecular charge-transfer (CT) band(15) (A) with full-width at half-maximum (FWHM) of 3522 cm–1 around 500–900 nm and two absorption maxima with FWHM of 3268 cm–1 at ca. 400 nm (B, see below for the assignment) and of 7627 cm–1 at ca. 300 nm (C; see below for the assignment) were observed in ethyl acetate under an ambient pressure (0.1 MPa) at room temperature. According to the ET definition,(14) the ET value in ethyl acetate at 0.1 MPa was determined to be 38.5 kcal mol–1 estimated from the absorption maximum of the A band, which is in good agreement with the literature value of 38.1 kcal mol–1.

Figure 2

Figure 2. UV/vis spectra of compound 1 in ethyl acetate (158 μM) at 0.1, 20, 40, 60, 80, 100, 120, 140, 160, 180, 200, 220, 240, 260, 280, and 300 MPa, measured in a high-pressure cell at room temperature.

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Gradual increase of the applied pressure from 0.1 to 300 MPa causes a monotonic hyperchromic effect at the whole spectral range studied since effective concentrations are elevated upon pressurization. The FWHM values of the three bands do not change throughout the applied hydrostatic pressure. On the other hand, the three absorption maxima behave very differently: the A band showed a steady hypsochromic shift from 742 nm at 0.1 MPa to 731 nm at 300 MPa with increasing hydrostatic pressure in sharp contrast to a slight bathochromic shift from 302 nm at 0.1 MPa to 306 nm at 300 MPa for the C band, whereas there are almost no changes for the B band. Similar pressure-induced shifts of the three bands were also observed in other solvents (see Figures S1–S7 in the Supporting Information (SI)).
As can be seen from Figure 3, the gradual shifts in the absorption bands A and C show both good linear relationships against the pressure applied, affording slopes (α) of αA = 0.80 cm–1 MPa–1 for the A band and of αC = −1.40 cm–1 MPa–1 for the C band, respectively. These slopes observed in other solvents are summarized in Table 1. Indicator 1 is spectroscopically susceptible to hydrostatic pressure stimuli, as expected. The apparent ET value at 300 MPa in ethyl acetate is 39.2 kcal mol–1, which is mostly equal to the one in chloroform at 0.1 MPa, and eventually, the value in methanol at 300 MPa reached 56.1 kcal mol–1, which is comparable to glycol (ET; 56.3 kcal mol–1) as a more polar solvent. From the dual indicator point of view, the two sensitive bands can mutually be used as a reference; the slopes at the A band in dichloromethane and 2-propanol are quite similar but those at the C band differ remarkably.

Figure 3

Figure 3. Plots of absorption maxima at (a) the C band (correlation coefficient r = 0.984) and (b) the A band (r = 0.963) in ethyl acetate.

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Table 1. Hydrostatic Pressure-Induced Spectral Changes of Reichardt’s Dye in Organic Solvents Examined
solventETa (kcal mol–1)αC (cm–1 MPa–1)αA (cm–1 MPa–1)
ethyl acetate38.1–1.400.80
chloroform39.1–1.511.01
dichloromethane40.7–1.641.38
acetone42.2b0.89
acetonitrile45.6–0.820.87
2-propanol48.4–1.101.39
ethanol51.9–0.981.34
methanol55.4–0.841.14
a

Empirical polarity parameters of solvents by Reichardt; see ref (14).

b

Not applicable.

The absorption spectrum has been simulated using TD-DFT(LRC-ωPBEh), including the lowest 200 singlet states. The theoretical spectrum is shifted by δλ = 134 nm to guide the eye and is shown in Figure 4 (blue line). Three CT bands are observed at 572, 688, and 930 nm. These three bands form the experimentally observed large A band around 800 nm. Both the shorter wavelength bands B and C are also reproduced at 301 and 392 nm and are attributed to a mix of local excitations (LE) and CT, and CT transitions, respectively.

Figure 4

Figure 4. Theoretical absorption spectra. In blue: absorption at the ground-state minimum geometry. In red: averaged absorption over 30 snapshot geometries taken from the AIMD propagation in the ground state. A bathochromic shift of δλ = 134 nm has been applied to the whole spectrum to align it on the experimental one. A broadening of Δ = 10 nm has been used.

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The peak calculated at 484 nm corresponds to the shoulder observed around 450 nm experimentally. The nature of the different peaks are illustrated by the difference of density associated to the transition from the ground state to the excited states with the largest oscillator strength; see Figures 5 and S8 (SI). All absorbing states are mainly of CT character, with a small mixing with local excitation (LE) occurring for the state lying within the absorption band around 300 nm. The average absorption spectrum calculated using 30 snapshots taken from an AIMD trajectory is shown in Figure 4 (red line). The motions in the ground state lead to a shift and a broadening of the CT band found at 930 nm. It spans from around 550–900 nm and is in good agreement with the experimentally observed band. Both peaks, at 484 and 392 nm, are shifted by 16 nm toward longer wavelengths (to 500 and 408 nm, respectively). The intense peak at 300 nm and the shoulder around 250 nm are qualitatively not affected by the ground-state molecular motions.

Figure 5

Figure 5. Difference of electronic densities between the states composing the main studied absorption bands and the ground state. When said band is comprised of several states, only one representative transition is shown. See Figure SI for a description of additional states. Red: loss of electronic density, blue: gain. The numbering of the state and its transition wavelength are shown below.

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The geometry of the minimum of energy in the ground state of 1 corresponds to a quasi C2 symmetry, with the C2 axis along the ON bond. The values of τi, defined in Figure 1, at this geometry are reported in Table 2. τ1 (31.1°) and τ2 (−49.9°) are rotations of part of the system around the C2 axis and therefore do not break the symmetry. The four other angles can be put into two groups: τ11 and τ12 (−53.2 and −51.0, respectively) and τ21 and τ22 (35.2 and 35.9, respectively).
Table 2. Values of the τi Angles, Their Average over the Dynamics (⟨τi⟩) and the Variance of Their Distribution over Time (σi)a
iτi⟨τi⟩σi
131.125.020.3
11–53.2–45.36.4
12–51.0–47.37.3
2–49.9–47.87.7
2135.229.78.6
2235.928.29.1
a

All values are reported in degrees.

The planarity of the molecule over the ground-state dynamics is investigated by looking at the τ angles along the AIMD trajectory. The distribution of the τ angles is shown in Figure 6 and the average value ⟨τi⟩ and the variance σi are reported in Table 2. Two different quasi normal distributions can be observed at ∼−47 and ∼27° corresponding to two minima. Angles τ11, τ12, and τ2 are rotations around neighboring C–C bonds. Because of the proximity of bulky groups (see Figure 1), the angles are constrained to larger values to minimize steric hindrance. τ1, τ21, and τ22 are the rotations of groups located at either end of the molecule. There, the steric hindrance is much smaller and the phenyl groups can adopt a conformation closer to planarity. With a variance of σ1 = 20.3°, τ1 is the most flexible angle. All the other five angles have significantly smaller variance (of about 7°) as they are constrained by steric hindrance. The two ending phenyl groups charactered by τ21 and τ22 have a slightly larger variance due to their position. These overall small variances stress out the spatial congestion and a planar conformation is unlikely even under the high-pressure conditions. This fact indicates that the spectral changes of the indicator 1 by pressurizing are highly likely not to originate from structural changes of the phenyl groups but rather from inherent changes of the solvent’s physical properties, i.e., refractive index and thus polarizability under high pressure.(16) The fact that the FWHM of the three experimentally observed bands do not change with the pressure points to the same conclusion as a change of the different τ angles would lead to a relative shift of the absorption energy of the electronic states depending on their nature.

Figure 6

Figure 6. Distribution of the angles (a) τ1, τ2, (b) τ11, τ21, and (c) τ12 and τ22 along the AIMD propagated in the ground state. When the distribution follows a normal law g(τi), this one is shown in black lines, where . ⟨τi⟩ and σi are reported in Table 2.

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The response of the energy of an electronic state to a change of polarity of its environment depends on the nature of the said state and on its dipole moment in particular. The absorption energy of a transition therefore depends on the difference of the dipole moment of the excited state and of the ground state . The electronic ground state has a dipole moment of along the direction. At equilibrium, the solvent accommodates this dipole and an increase of polarity of the environment will further stabilize the ground state.
The first excited state S1, composing the band A, is a charge transfer from the “bottom” to the “top” of the molecule, i.e., in the same direction of . This CT induces a flip of the dipole moment in the excited state: along the direction. The capacity of the solvent to reorganize to accommodate this large dipole moment change is hindered by the increase of pressure. This leads to an increase of the absorption energy and therefore to the hypsochromic shift of the A band observed experimentally.
The main electronic states composing the absorption band C have a dipole moment in the same direction as but of lower intensity. The interaction of these states with the solvent is therefore weaker than the ground state interaction with the environment. Increasing the pressure brings the solvent molecule out of their equilibrium geometry and the ground state is therefore destabilized. This destabilization is not as large for the electronic excited states composing the C absorption band as their dipole moment, and therefore, their interaction with the solvent is smaller. This results in a decrease of the energy gap between the ground state and the states composing the C absorption band and therefore to a bathochromic shift of the C band.
Therefore, the contrasting pressure-induced wavelength shifts of the A and the C bands can be attributed to the relative stabilization of ground or excited states, respectively, as were the cases with those observed in aromatic compounds accompanied by red shifts (related to 1LE transitions) upon hydrostatic pressurization.(13m,17)

3. Conclusions

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In conclusion, we have demonstrated the spectral controls of Reichardt’s dye induced by hydrostatic pressure, enabling it to be used as a colorimetric polarity/pressure dual indicator. The pressure-induced spectral changes are very contrasted at the A and C bands, the origins of which were supported by the TD-DFT calculations. It can be therefore emphasized that the present approach thus observed by using Reichardt’s dye may be expandable to other chromophores and/or fluorophores for developing further dual indicators.

4. EXPERIMENTAL SECTION

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4.1. General

UV/vis spectra were recorded on JASCO V-560. Spectrophotometric grade solvents and Reichardt’s dye were used without further purification.

4.2. Computational Details

All calculations were performed with the long range corrected LRC-ωPBEh functional(18a) and the 6-31G* Pople basis set(18b,c) within the Qchem 5.0 package.(18d) The range separation parameter ω = 0.148a0–1 was determined using the optimal tuning procedure that have proven efficient for organic molecule exhibiting low lying charge transfer states.(18e,f) The ground state minimum geometry has been optimized with DFT and a frequency analysis has been performed to ensure there were no imaginary frequencies. The electronic structure was computed with Time Dependent DFT (TD-DFT) within the Tamm-Dancoff approximation.(18g) The absorption spectrum was both determined by TD-DFT calculations including the lowest 200 singlet states and by averaging the absorption spectra of 30 different structures taken randomly along an ab initio molecular dynamics simulation performed with TeraChem(18h) with the 3-21G* basis set(18i,j) and the PBE functional,(18k,l) including the DFT-D3 Grimme dispersion correction.(18m) The oscillator strength of each transition (fn) of energy ωn was broadened with a Gaussian functionwhere Δ is the full-width at half maximum set to 10 nm.

4.3. General Procedure for Measurements under Hydrostatic Pressure

UV/vis spectroscopic experiments under high pressure were performed by using the high-pressure apparatus reported previously.(19) A solution of a given concentration of compound 1 was introduced to a quartz cell for high pressure (3 mm width, 2 mm depth, and 7 mm height). The quartz cell was connected to a Teflon tube for adjusting the applied pressure, sealed by a metal stopper, and then placed in the high pressure apparatus. The sample solution thus put into the apparatus was measured by UV/vis spectroscopy upon hydrostatically pressurization from 0.1 to 300 MPa.

Supporting Information

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The Supporting Information is available free of charge at https://pubs.acs.org/doi/10.1021/acsomega.9b03880.

  • UV/vis spectra of the compound 1 under high pressure and difference of electronic associated to the most absorbing transition (PDF)

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Most electronic Supporting Information files are available without a subscription to ACS Web Editions. Such files may be downloaded by article for research use (if there is a public use license linked to the relevant article, that license may permit other uses). Permission may be obtained from ACS for other uses through requests via the RightsLink permission system: http://pubs.acs.org/page/copyright/permissions.html.

Author Information

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  • Corresponding Authors
  • Authors
    • Akihisa Miyagawa - Department of Chemistry, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8551, Japan
    • Tetsuo Okada - Department of Chemistry, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8551, Japan;  Orcidhttp://orcid.org/0000-0002-1976-7936
    • Yoshihisa Inoue - Department of Applied Chemistry, Osaka University, 2-1 Yamada-oka, Suita 565-0871, Japan;  Orcidhttp://orcid.org/0000-0001-6018-0558
    • Thomas James Penfold - Chemistry- School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne NE1 7RU, U.K.
  • Notes

    The authors declare no competing financial interest.

Acknowledgments

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This work was supported by Grant-in-Aid for Scientific Research (B) (No. 19H02746) from JSPS and Japan Science Technology Agency (JST), PRESTO (No. JPMJPR17PA), and by the EPSRC through grants EP/N028511/1, EP/R021503/1 and EP/P012388/1, all of which are gratefully appreciated. Data supporting this publication are openly available under a “Creative Commons License.” Additional meta-data are available at 10.25405/data.ncl.11336633. Please contact Newcastle Research Data Service at [email protected] for access instructions.

References

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This article references 19 other publications.

  1. 1
    (a) Wang, B.; Anslyn, E. V., Eds.; Chemosensors: Principles, Strategies, and Applications; Wiley: Hoboken, 2011.
    [Crossref], Google Scholar
    There is no corresponding record for this reference.
    (b) Fukuhara, G. Polymer-based supramolecular sensing and application to chiral photochemistry. Polym. J. 2015, 47, 649– 655,  DOI: 10.1038/pj.2015.52
    [Crossref], [CAS], Google Scholar
    1b
    Polymer-based supramolecular sensing and application to chiral photochemistry
    Fukuhara, Gaku
    Polymer Journal (Tokyo, Japan) (2015), 47 (10), 649-655CODEN: POLJB8; ISSN:0032-3896. (NPG Nature Asia-Pacific)
    A review. Supramol. sensing using polymers is of particular significance not only for fundamental science but also for a no. of practical diagnostic applications because, upon interaction with target analytes, polymers are capable of amplifying the binding events and thus greatly enhance the signal gain. Hence, we proposed the construction of supramol. sensors based on chiral functional polymers, such as synthetic conjugated polymers and modified polysaccharides, which are responsive to biol. important chiral materials and saccharides. The present strategy using polymer hosts that behave very differently from those commonly employed in conventional chemosensors is based on the chirality or mol. information propagation and amplification in the polymer chains. By exploiting the knowledge and techniques obtained from the polymer-based supramol. sensing of bio-related materials, we have expanded the research to photochem. asym. synthesis, or 'photochirogenesis,' which provides ecol. benign yet versatile routes to optically active compds. via electronically excited states and is also one of the most attractive and challenging topics in current chem. In this review, the author highlights polymer-based supramol. sensing and application to photochirogenesis with recent examples.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhs1SlurrK&md5=b073d02d5e483cf6952881cb504c7d6d
    .
    (c) Fukuhara, G. Allosteric signal-amplification sensing with polymer-based supramolecular hosts. J. Incl. Phenom. Macrocycl. Chem. 2019, 93, 127– 143,  DOI: 10.1007/s10847-019-00881-2
    [Crossref], Google Scholar
    There is no corresponding record for this reference.
  2. 2
    (a) Tamura, Z.; Terada, R.; Ohno, K.; Maeda, M. Features of Phenolsulfonphthalein and Phenolphthalein Substituted at All Ortho-Positions of Phenols with Bromine. Anal. Sci. 1999, 15, 339– 342,  DOI: 10.2116/analsci.15.339
    [Crossref], [CAS], Google Scholar
    2a
    Features of phenolsulfonphthalein and phenolphthalein substituted at all ortho-positions of phenols with bromine
    Tamura, Zenzo; Terada, Rimi; Ohno, Kennichi; Maeda, Masako
    Analytical Sciences (1999), 15 (4), 339-342CODEN: ANSCEN; ISSN:0910-6340. (Japan Society for Analytical Chemistry)
    The influence of bromination at all the ortho-positions of phenols on the features of phenolsulfonphthalein and phenolphthalein was investigated. The absorption spectra of Bromphenol Blue (H2BPS) in phosphate buffers demonstrated the complete opening of the lactone ring to form yellow HBPS- at pH 1 where pK2=3.8. The reaction of hydroxide ion with blue BPS2- to produce colorless BPS(OH)3- required heating where pK3=9. On the contrary, the spectra of 3',3'',5',5''-tetrabromophenolphthalein (H2BPP) demonstrated that the lactone ring was very stable. More than 99.5% of BPP2- species consisted of a colorless lactone possessing two isolated phenol groups where pK'1=6.0 and pK'2=6.8; the reaction of hydroxide ion with BPP2- to produce BPP(OH)3- was slow where pK3=10.3. These results indicate the increased acidity of phenols and the greater tendency of the central carbon atom to act as an electron acceptor.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1MXisVSntL8%253D&md5=66ebb9b56c747fdfa53a77f4ba0feabe
    .
    (b) Qu, F.; Li, N. B.; Luo, H. Q. Highly Sensitive Fluorescent and Colorimetric pH Sensor Based on Polyethylenimine-Capped Silver Nanoclusters. Langmuir 2013, 29, 1199– 1205,  DOI: 10.1021/la304558r
    [ACS Full Text ACS Full Text], [CAS], Google Scholar
    2b
    Highly Sensitive Fluorescent and Colorimetric pH Sensor Based on Polyethylenimine-Capped Silver Nanoclusters
    Qu, Fei; Li, Nian Bing; Luo, Hong Qun
    Langmuir (2013), 29 (4), 1199-1205CODEN: LANGD5; ISSN:0743-7463. (American Chemical Society)
    Silver nanoclusters capped by hyperbranched polyethylenimine (PEI) have been developed as a highly sensitive fluorescent and colorimetric pH sensor. The probe responds rapidly to pH fluctuations and has such absorption characteristics that the color changes from the colorless or a nearly colorless state to a colored state with increasing acidity, so PEI-capped Ag nanoclusters could be used as a color indicator for colorimetric pH detection. Quant., the fluorescence intensity of PEI-capped Ag nanoclusters exhibits a linear fashion over the pH range of 5.02-7.96 and increases by around 10-fold approx. with greater fluorescence at higher pH values. The repulsion development and conformational change of PEI with decreasing pH induce the aggregation of Ag nanoclusters, leading to an obvious color change and fluorescence quenching of Ag nanoclusters at low pH values. As expected, the pH probe is also sensitive to the different buffer solns., except for those contg. some anions that could react with Ag nanoclusters. Besides, the ionic strength of the buffers has a little influence on the pH-responsive behavior. The authors' pH sensor with nanoscaled phys. dimensions would be a promising candidate in the applications in biol., medical, and pharmaceutical fields.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXitVGjsg%253D%253D&md5=1157106375d555aee40fefab42fe7388
    .
    (c) Noh, J. Y.; Park, G. J.; Na, Y. J.; Jo, H. Y.; Lee, S. A.; Kim, C. A colorimetric “naked-eye” Cu(II) chemosensor and pH indicator in 100% aqueous solution. Dalton Trans. 2014, 43, 5652– 5656,  DOI: 10.1039/C3DT53637H
    [Crossref], [PubMed], [CAS], Google Scholar
    2c
    A colorimetric "naked-eye" Cu2+ chemosensor and pH indicator in 100% aqueous solution
    Noh, Jin Young; Park, Gyeong Jin; Na, Yu Jeong; Jo, Hyun Yong; Lee, Seul Ah; Kim, Cheal
    Dalton Transactions (2014), 43 (15), 5652-5656CODEN: DTARAF; ISSN:1477-9226. (Royal Society of Chemistry)
    A new, highly selective and sensitive colorimetric chemosensor for detection of Cu2+ ions in aq. soln. was developed. Receptor detected Cu2+ ions by changing its color from colorless to yellow. Also, the Cu2+-sensitive compd. was used as a colorimetric pH detector based on a color change due to 1-Cu2+ complex formation identifiable by the naked eye.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXktl2kurg%253D&md5=f5725c1d032c357b302eeaa81ebad125
  3. 3
    (a) Yeung, M. C.-L.; Yam, V. W.-W. Luminescent cation sensors: from host-guest chemistry, supramolecular chemistry to reaction-based mechanisms. Chem. Soc. Rev. 2015, 44, 4192– 4202,  DOI: 10.1039/C4CS00391H
    [Crossref], [PubMed], [CAS], Google Scholar
    3a
    Luminescent cation sensors: from host-guest chemistry, supramolecular chemistry to reaction-based mechanisms
    Yeung, Margaret Ching-Lam; Yam, Vivian Wing-Wah
    Chemical Society Reviews (2015), 44 (13), 4192-4202CODEN: CSRVBR; ISSN:0306-0012. (Royal Society of Chemistry)
    Other than traditional cation detection strategies, which are solely based on the ion-receptor complementarity, the extension of the concept of supramol. chem. and the mechanisms of irreversible analyte-specific reactions have also been integrated into the design of luminescent probes for the detection of cation in view of the exploration of highly sensitive and selective sensors. In this highlight, a versatile range of org. and organometallic architectures with cation-sensing capabilities based on the above mechanisms will be discussed.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXos1SntQ%253D%253D&md5=e12c4f4ba052e5531ec3c2f8dd0dfa22
    .
    (b) Busschaert, N.; Caltagirone, C.; Rossom, W. V.; Gale, P. A. Applications of Supramolecular Anion Recognition. Chem. Rev. 2015, 115, 8038– 8155,  DOI: 10.1021/acs.chemrev.5b00099
    [ACS Full Text ACS Full Text], [CAS], Google Scholar
    3b
    Applications of Supramolecular Anion Recognition
    Busschaert, Nathalie; Caltagirone, Claudia; Van Rossom, Wim; Gale, Philip A.
    Chemical Reviews (Washington, DC, United States) (2015), 115 (15), 8038-8155CODEN: CHREAY; ISSN:0009-2665. (American Chemical Society)
    A review. This review focuses on the applications of anion complexation in research over the past decade. This spans a wide range of areas, but for the purposes of this review are divided into sensing, extn., transport through lipid bilayers, the roles anions can play in the formation of mol. assemblies, and, finally, organocatalysis.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXovVSnsrg%253D&md5=e5ae6d6d1effcedacac74796c81ce485
  4. 4
    (a) Elosua, C.; Matias, I. R.; Bariain, C.; Arregui, F. J. Volatile Organic Compound Optical Fiber Sensors: A Review. Sensors 2006, 6, 1440– 1465,  DOI: 10.3390/s6111440
    [Crossref], [CAS], Google Scholar
    4a
    Volatile organic compound optical fiber sensors: a review
    Elosua, Cesar; Matias, Ignacio R.; Bariain, Candido; Arregui, Francisco J.
    Sensors (2006), 6 (11), 1440-1465CODEN: SENSC9; ISSN:1424-8220. (Molecular Diversity Preservation International)
    A review. Volatile org. compd. (VOC) detection is a topic of growing interest with applications in diverse fields, ranging from environmental uses to the food or chem. industries. Optical fiber VOC sensors offering new and interesting properties which overcame some of the inconveniences found on traditional gas sensors appeared over two decades ago. Thanks to its min. invasive nature and the advantages that optical fiber offers such as light wt., passive nature, low attenuation and the possibility of multiplexing, among others, these sensors are a real alternative to electronic ones in elec. noisy environments where electronic sensors cannot operate correctly. A classification of these devices was made according to the sensing mechanism and taking also into account the sensing materials or the different methods of fabrication. Some solns. already implemented for the detection of VOCs using optical fiber sensors will be described with detail.
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    .
    (b) Lee, M. Y.; Lee, H. R.; Park, C. H.; Han, S. G.; Oh, J. H. Organic Transistor-Based Chemical Sensors for Wearable Bioelectronics. Acc. Chem. Res. 2018, 51, 2829– 2838,  DOI: 10.1021/acs.accounts.8b00465
    [ACS Full Text ACS Full Text], [CAS], Google Scholar
    4b
    Organic Transistor-Based Chemical Sensors for Wearable Bioelectronics
    Lee, Moo Yeol; Lee, Hae Rang; Park, Cheol Hee; Han, Seul Gi; Oh, Joon Hak
    Accounts of Chemical Research (2018), 51 (11), 2829-2838CODEN: ACHRE4; ISSN:0001-4842. (American Chemical Society)
    A review. Bioelectronics for healthcare that monitor the health information on users in real time have stepped into the limelight as crucial electronic devices for the future due to the increased demand for "point-of-care" testing, which is defined as medical diagnostic testing at the time and place of patient care. In contrast to traditional diagnostic testing, which is generally conducted at medical institutions with diagnostic instruments and requires a long time for specimen anal., point-of-care testing can be accomplished personally at the bedside, and health information on users can be monitored in real time. Advances in materials science and device technol. have enabled next-generation electronics, including flexible, stretchable, and biocompatible electronic devices, bringing the commercialization of personalized healthcare devices increasingly within reach, e.g., wearable bioelectronics attached to the body that monitor the health information on users in real time. Addnl., the monitoring of harmful factors in the environment surrounding the user, such as air pollutants, chems., and UV light, is also important for health maintenance because such factors can have short- and long-term detrimental effects on the human body. The precise detection of chem. species from both the human body and the surrounding environment is crucial for personal health care because of the abundant information that such factors can provide when detg. a person's health condition. In this respect, sensor applications based on an org.-transistor platform have various advantages, including signal amplification, mol. design capability, low cost, and mech. robustness (e.g., flexibility and stretchability).This Account covers recent progress in org. transistor-based chem. sensors that detect various chem. species in the human body or the surrounding environment, which will be the core elements of wearable electronic devices. There has been considerable effort to develop high-performance chem. sensors based on org.-transistor platforms through material design and device engineering. Various exptl. approaches have been adopted to develop chem. sensors with high sensitivity, selectivity, and stability, including the synthesis of new materials, structural engineering, surface functionalization, and device engineering. In this Account, we first provide a brief introduction to the operating principles of transistor-based chem. sensors. Then we summarize the progress in the fabrication of transistor-based chem. sensors that detect chem. species from the human body (e.g., mols. in sweat, saliva, urine, tears, etc.). We then highlight examples of chem. sensors for detecting harmful chems. in the environment surrounding the user (e.g., nitrogen oxides, sulfur dioxide, volatile org. compds., liq.-phase org. solvents, and heavy metal ions). Finally, we conclude this Account with a perspective on the wearable bioelectronics, esp. focusing on org. electronic materials and devices.
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  5. 5
    (a) Salinas, Y.; Martínez-Máñez, R.; Marcos, M. D.; Sancenón, F.; Costero, A. M.; Parra, M.; Gil, S. Optical chemosensors and reagents to detect explosives. Chem. Soc. Rev. 2012, 41, 1261– 1296,  DOI: 10.1039/C1CS15173H
    [Crossref], [PubMed], [CAS], Google Scholar
    5a
    Optical chemosensors and reagents to detect explosives
    Salinas, Yolanda; Martinez-Manez, Ramon; Marcos, Maria D.; Sancenon, Felix; Costero, Ana M.; Parra, Margarita; Gil, Salvador
    Chemical Society Reviews (2012), 41 (3), 1261-1296CODEN: CSRVBR; ISSN:0306-0012. (Royal Society of Chemistry)
    This crit. review is focused on examples reported from 1947 to 2010 related to the design of chromo-fluorogenic chemosensors and reagents for explosives (141 refs.).
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    .
    (b) Schroeder, V.; Savagatrup, S.; He, M.; Lin, S.; Swager, T. M. Carbon Nanotube Chemical Sensors. Chem. Rev. 2019, 119, 599– 663,  DOI: 10.1021/acs.chemrev.8b00340
    [ACS Full Text ACS Full Text], [CAS], Google Scholar
    5b
    Carbon Nanotube Chemical Sensors
    Schroeder, Vera; Savagatrup, Suchol; He, Maggie; Lin, Sibo; Swager, Timothy M.
    Chemical Reviews (Washington, DC, United States) (2019), 119 (1), 599-663CODEN: CHREAY; ISSN:0009-2665. (American Chemical Society)
    Carbon nanotubes (CNTs) promise to advance a no. of real-world technologies. Of these applications, they are particularly attractive for uses in chem. sensors for environmental and health monitoring. However, chem. sensors based on CNTs are often lacking in selectivity, and the elucidation of their sensing mechanisms remains challenging. This review is a comprehensive description of the parameters that give rise to the sensing capabilities of CNT-based sensors and the application of CNT-based devices in chem. sensing. This review begins with the discussion of the sensing mechanisms in CNT-based devices, the chem. methods of CNT functionalization, architectures of sensors, performance parameters, and theor. models used to describe CNT sensors. It then discusses the expansive applications of CNT-based sensors to multiple areas including environmental monitoring, food and agriculture applications, biol. sensors, and national security. The discussion of each analyte focuses on the strategies used to impart selectivity and the mol. interactions between the selector and the analyte. Finally, the review concludes with a brief outlook over future developments in the field of chem. sensors and their prospects for commercialization.
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  6. 6
    (a) Hembury, G. A.; Borovkov, V. V.; Inoue, Y. Chirality-Sensing Supramolecular Systems. Chem. Rev. 2008, 108, 1– 73,  DOI: 10.1021/cr050005k
    [ACS Full Text ACS Full Text], [CAS], Google Scholar
    6a
    Chirality-Sensing Supramolecular Systems
    Hembury, Guy A.; Borovkov, Victor V.; Inoue, Yoshihisa
    Chemical Reviews (Washington, DC, United States) (2008), 108 (1), 1-73CODEN: CHREAY; ISSN:0009-2665. (American Chemical Society)
    A review. A detailed understanding of the underpinning mechanisms and various influencing factors is of particular significance for smart control and further useful application of chiral supramol. science. Considering the vast body of literature on the subject of supramol. chirality generation (or chirogenesis), it is clear that the modes of chiral mol. communication are largely noncovalent in nature; primarily, these include attractive or repulsive electrostatic interactions, hydrogen bonding, van der Waals contacts, π-π interactions, and repulsive steric interactions, with these acting either independently or cooperatively to produce the obsd. chiral structures. Thus, it is with this in mind that we must approach the analyses of such dynamic supramol. chiral systems, with recent years showing a great increase in the sophistication with which research groups have been able to rationalize and apply supramol. principles to a large range of complex chiral assemblies.
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    .
    (b) Yashima, E.; Ousaka, N.; Taura, D.; Shimomura, K.; Ikai, T.; Maeda, K. Supramolecular Helical Systems: Helical Assemblies of Small Molecules, Foldamers, and Polymers with Chiral Amplification and Their Functions. Chem. Rev. 2016, 116, 13752– 13990,  DOI: 10.1021/acs.chemrev.6b00354
    [ACS Full Text ACS Full Text], [CAS], Google Scholar
    6b
    Supramolecular Helical Systems: Helical Assemblies of Small Molecules, Foldamers, and Polymers with Chiral Amplification and Their Functions
    Yashima, Eiji; Ousaka, Naoki; Taura, Daisuke; Shimomura, Kouhei; Ikai, Tomoyuki; Maeda, Katsuhiro
    Chemical Reviews (Washington, DC, United States) (2016), 116 (22), 13752-13990CODEN: CHREAY; ISSN:0009-2665. (American Chemical Society)
    A review. In this review, we describe the recent advances in supramol. helical assemblies formed from chiral and achiral small mols., oligomers (foldamers), and helical and nonhelical polymers from the viewpoints of their formations with unique chiral phenomena, such as amplification of chirality during the dynamic helically assembled processes, properties, and specific functionalities, some of which have not been obsd. in or achieved by biol. systems. In addn., a brief historical overview of the helical assemblies of small mols. and remarkable progress in the synthesis of single-stranded and multistranded helical foldamers and polymers, their properties, structures, and functions, mainly since 2009, will also be described.
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  7. 7
    (a) Kubota, R.; Hamachi, I. Protein recognition using synthetic small-molecular binders toward optical protein sensing in vitro and in live cells. Chem. Soc. Rev. 2015, 44, 4454– 4471,  DOI: 10.1039/C4CS00381K
    [Crossref], [PubMed], [CAS], Google Scholar
    7a
    Protein recognition using synthetic small-molecular binders toward optical protein sensing in vitro and in live cells
    Kubota, Ryou; Hamachi, Itaru
    Chemical Society Reviews (2015), 44 (13), 4454-4471CODEN: CSRVBR; ISSN:0306-0012. (Royal Society of Chemistry)
    Chem. sensing of amino acids, peptides, and proteins provides fruitful information to understand their biol. functions, as well as to develop the medical and technol. applications. To detect amino acids, peptides, and proteins in vitro and in vivo, vast kinds of chem. sensors including small synthetic binders/sensors, genetically-encoded fluorescent proteins and protein-based semisynthetic biosensors have been intensely investigated. This review deals with concepts, strategies, and applications of protein recognition and sensing using small synthetic binders/sensors, which are now actively studied but still in the early stage of investigation. The recognition strategies for peptides and proteins can be divided into three categories: (i) recognition of protein substructures, (ii) protein surface recognition, and (iii) protein sensing through protein-ligand interaction. Here, we overview representative examples of protein recognition and sensing, and discuss biol. or diagnostic applications such as potent inhibitors/modulators of protein-protein interactions.
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    .
    (b) Zwang, T. J.; Tse, E. C. M.; Barton, J. K. Sensing DNA through DNA Charge Transport. ACS Chem. Biol. 2018, 13, 1799– 1809,  DOI: 10.1021/acschembio.8b00347
    [ACS Full Text ACS Full Text], [CAS], Google Scholar
    7b
    Sensing DNA through DNA Charge Transport
    Zwang, Theodore J.; Tse, Edmund C. M.; Barton, Jacqueline K.
    ACS Chemical Biology (2018), 13 (7), 1799-1809CODEN: ACBCCT; ISSN:1554-8929. (American Chemical Society)
    A review. DNA charge transport chem. involves the migration of charge over long mol. distances through the arom. base pair stack within the DNA helix. This migration depends upon the intimate coupling of bases stacked one with another, and hence any perturbation in that stacking, through base modifications or protein binding, can be sensed elec. In this review, the authors describe the many ways DNA charge transport chem. has been utilized to sense changes in DNA, including the presence of lesions, mismatches, DNA-binding proteins, protein activity, and even reactions under weak magnetic fields. Charge transport chem. is remarkable in its ability to sense the integrity of DNA.
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  8. 8
    (a) Andón, F. T.; Fadeel, B. Programmed Cell Death: Molecular Mechanisms and Implications for Safety Assessment of Nanomaterials. Acc. Chem. Res. 2013, 46, 733– 742,  DOI: 10.1021/ar300020b
    [ACS Full Text ACS Full Text], [CAS], Google Scholar
    8a
    Programmed Cell Death: Molecular Mechanisms and Implications for Safety Assessment of Nanomaterials
    Andon, Fernando Torres; Fadeel, Bengt
    Accounts of Chemical Research (2013), 46 (3), 733-742CODEN: ACHRE4; ISSN:0001-4842. (American Chemical Society)
    A review. Engineered nanomaterials offer numerous and tantalizing opportunities in many sectors of society, including medicine. Needless to say, attention should also be paid to the potential for unexpected hazardous effects of these novel materials. To date, much of the nanotoxicol. literature has focused on the assessment of cell viability or cell death using primitive assays for the detection of plasma membrane integrity or mitochondrial function or assessment of cellular morphol. However, when assessing the cytotoxic effects of engineered nanomaterials, researchers need not only to consider whether cells are dead or alive but also to assess which of the numerous, highly specific pathways of cell death might be involved. Moreover, it is important to diagnose cell death based not only on morphol. markers but on the assessment and quantification of biochem. alterations specific to each form of cell death. In this Account, we provide a description of the three major forms of programmed cell death in mammalian cells: apoptosis, autophagic cell death, and regulated necrosis, sometimes referred to as necroptosis. Apoptosis can be activated via the extrinsic (death receptor-dependent) or via the intrinsic (mitochondria-dependent) route. Apoptotic cell death may or may not require the activation of cytosolic proteases known as caspases. Autophagy (self-eating) has an important homeostatic role in the cell, mediating the removal of dysfunctional or damaged organelles thereby allowing the recycling of cellular building blocks. However, unrestrained autophagy can kill cells. Studies in recent years have revealed that necrosis that depends on activation of the kinases RIP1 and RIP3 is a major form of programmed cell death with roles in development and immunity. We also discuss recent examples of the impact of engineered nanoparticles on the three different pathways of programmed cell death. For example, acute exposure of cells to carbon nanotubes (CNTs) can induce apoptosis whereas chronic exposure to CNTs may yield an apoptosis-resistant and tumorigenic phenotype in lung epithelial cells. Several reports show that nanoparticles, including polystyrene particles, are routed to the lysosomal compartment and trigger cell death through the destabilization of lysosomal membranes with engagement of the intrinsic apoptosis pathway. In addn., a no. of studies have demonstrated that nanomaterials such as CNTs, quantum dots, and gold nanoparticles can affect cellular autophagy. An improved understanding of the complexities of the nanomaterial-induced perturbation of different cell death pathways may allow for a better prediction of the consequences of human exposure.
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    .
    (b) Vadevoo, S. M. P.; Gurung, S.; Khan, F.; Haque, M. E.; Gunassekaran, G. R.; Chi, L.; Permpoon, U.; Lee, B. Peptide-based targeted therapeutics and apoptosis imaging probes for cancer therapy. Arch. Pharm. Res. 2019, 42, 150– 158,  DOI: 10.1007/s12272-019-01125-0
    [Crossref], [PubMed], [CAS], Google Scholar
    8b
    Peptide-based targeted therapeutics and apoptosis imaging probes for cancer therapy
    Vadevoo, Sri Murugan Poongkavithai; Gurung, Smriti; Khan, Fatima; Haque, Md. Enamul; Gunassekaran, Gowri Rangaswamy; Chi, Lianhua; Permpoon, Uttapol; Lee, Byungheon
    Archives of Pharmacal Research (2019), 42 (2), 150-158CODEN: APHRDQ; ISSN:0253-6269. (Pharmaceutical Society of Korea)
    A review. Peptides have advantages over antibodies in terms of deep tissue penetration, low immunogenicity, and cost-effective prodn., but they have short circulation time and poor stability in vivo. Peptides have been extensively used as targeting moieties for the delivery of drug-loaded nanoparticles and function as targeted therapeutics in cancer treatment. Here, we review peptides that are exploited as targeted therapeutics in cancer therapy and apoptosis imaging probes for the monitoring of treatment responses.
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  9. 9
    (a) Rekharsky, M. V.; Inoue, Y. Complexation Thermodynamics of Cyclodextrins. Chem. Rev. 1998, 98, 1875– 1917,  DOI: 10.1021/cr970015o
    [ACS Full Text ACS Full Text], [CAS], Google Scholar
    9a
    Complexation Thermodynamics of Cyclodextrins
    Rekharsky, Mikhail V.; Inoue, Yoshihisa
    Chemical Reviews (Washington, D. C.) (1998), 98 (5), 1875-1917CODEN: CHREAY; ISSN:0009-2665. (American Chemical Society)
    A review with 287 refs. aimed at expanding and updating the thermodn. data collected in the authors' previous papers. A better understanding of the nature of inclusion complexation by natural and modified cyclodextrins will be obtained.
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    .
    (b) Fukuhara, G.; Okazaki, T.; Lessi, M.; Nishijima, M.; Yang, C.; Mori, T.; Mele, A.; Bellina, F.; Chiappe, C.; Inoue, Y. Chiral ionic liquid-mediated photochirogenesis. Enantiodifferentiating photocyclodimerization of 2-anthracenecarboxylic acid. Org. Biomol. Chem. 2011, 9, 7105– 7112,  DOI: 10.1039/c1ob05716b
    [Crossref], [PubMed], [CAS], Google Scholar
    9b
    Chiral ionic liquid-mediated photochirogenesis. Enantiodifferentiating photocyclodimerization of 2-anthracenecarboxylic acid
    Fukuhara, Gaku; Okazaki, Takahiro; Lessi, Marco; Nishijima, Masaki; Yang, Cheng; Mori, Tadashi; Mele, Andrea; Bellina, Fabio; Chiappe, Cinzia; Inoue, Yoshihisa
    Organic & Biomolecular Chemistry (2011), 9 (20), 7105-7112CODEN: OBCRAK; ISSN:1477-0520. (Royal Society of Chemistry)
    Enantiodifferentiating photocyclodimerization of 2-anthracenecarboxylic acid (AC-H) and its lithium salt (AC-Li) in chiral ionic liq. (CIL), (R)-1-(2,3-dihydroxypropyl)-3-methylimidazolium acetate {[(R)-GLYMI][AcO]}, gave a mixt. of two head-to-tail (HT) and two head-to-head (HH) cyclodimers in HT/HH ratios of 1.3-1.7 (for AC-H) and 2.2-4.3 (for AC-Li) with low enantiomeric excesses (ee) of 0-3% for chiral syn-HT and anti-HH dimers. In contrast, irradn. of AC-H in an aq. soln., contg. cucurbit[8]uril (CB[8]) as a host and [(R)-GLYMI][AcO] or [(R)-GLYMI][Tf2N] as a modifier of CB portals, afforded the HH dimers in 91-99% selectivity, although the anti-HH dimer was totally racemic. Interestingly, irradn. of AC-H in a dichloromethane soln., contg. [(R)-GLYMI][AcO] as a chiral template, led to the formation of the HH-dimers in 98% selectivity with chiral anti-HH dimer in -14% ee, presumably by the dual ligation of two ACs to a CIL through electrostatic and hydrogen-bonding interactions.
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  10. 10
    (a) Inoue, Y.; Ikeda, H.; Kaneda, M.; Sumimura, T.; Everitt, S. R. L.; Wada, T. Entropy-Controlled Asymmetric Photochemistry: Switching of Product Chirality by Solvent. J. Am. Chem. Soc. 2000, 122, 406– 407,  DOI: 10.1021/ja993542t
    [ACS Full Text ACS Full Text], [CAS], Google Scholar
    10a
    Entropy-Controlled Asymmetric Photochemistry: Switching of Product Chirality by Solvent
    Inoue, Yoshihisa; Ikeda, Haruhiko; Kaneda, Masayuki; Sumimura, Toshiaki; Everitt, Simon R. L.; Wada, Takehiko
    Journal of the American Chemical Society (2000), 122 (2), 406-407CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)
    Enantiodifferentiating photoisomerization of achiral (Z)-cyclooctene (1Z) was studied in the presence of chiral sensitizers (optically active terpenoid or saccharide esters of benzenetetracarboxylic acid; 2a and 2b resp.) in pentane or di-Et ether at different temp. from -110 to 25° C. The reaction gave chiral (E)-cyclooctene (1E) with varying enantiomeric excess (ee) levels, in good to excellent chem. yields. Both chiral sensitizers afforded comparable ee values of approx. -5% at 25° C in both pentane and ether (the neg. sign indicates the predominant formation of the (R)-(-)-isomer), but gave distinctly different ee's at lower temps. When the menthyl ester 2a was used as a sensitizer, the ee of the product showed very similar temp. dependencies in both pentane and ether. Thus, the major enantiomer produced was switched from (R)- to (S)-1E at the equipodal temp., T0 = -19° C, and thereafter the ee continued to increase as the temp. was further reduced. In contrast, the use of the saccharide ester 2b led to opposite tendencies in the same solvents at lower temps. Thus, lowering the reaction temp. enhanced the prodn. of (R)-1E in pentane, but the enantioselectivity was switched to (S)-1E in ether, giving an ee of 73% at -110° C, which is the highest ee ever reported for an enantiodifferentiating photosensitization. To elucidate the nature of this important solvent effect, the authors performed enantiodifferentiating photosensitizations with 2b in several solvents, allowing them to investigate a range of different polarities.
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    .
    (b) Inoue, Y.; Wada, T.; Asaoka, S.; Sato, H.; Pete, J.-P. Photochirogenesis: multidimensional control of asymmetric photochemistry. Chem. Commun. 2000, 251– 259,  DOI: 10.1039/a905409j
    [Crossref], [CAS], Google Scholar
    10b
    Photochirogenesis: multidimensional control of asymmetric photochemistry
    Inoue, Yoshihisa; Wada, Takehiko; Asaoka, Sadayuki; Sato, Hirofumi; Pete, Jean-Pierre
    Chemical Communications (Cambridge) (2000), (4), 251-259CODEN: CHCOFS; ISSN:1359-7345. (Royal Society of Chemistry)
    A review with 37 refs. Photochirogenesis, or photochem. induction of mol. chirality, is an attractive alternative to thermal or enzymic asym. synthesis. Using the inherent advantage that the photochem. reaction is driven by light absorption, the effect of temp. on optical yield was investigated over a wide range. Unexpectedly, the stereochem. of photoproduct was frequently inverted at a crit. temp. (T0), above which the optical yield increased with increasing temp. The Eyring treatment of the relative rate const. for the prodn. of each enantiomer revealed that the unusual temp. dependency originates from the non-zero differential entropy of activation for the enantiodifferentiating process. In this case, the enthalpy term dominates at lower temps., while the entropy term becomes more important above T0, switching the product chirality. The abs. configuration of photoproduct obtained at temps. lower than T0 was correlated to that of the chiral sensitizer, except for those contg. very bulky chiral auxiliaries, the stereochem. outcomes are discussed on the basis of the mol. model examns. Interestingly, similar switching behavior was induced by varying the pressure from 0.1 to 400 MPa. The pressure effect was investigated at different temps. to construct three-dimensional diagrams that correlate the optical yield with temp. and pressure as mutually independent factors. The combined use of temp. and pressure provides us with a convenient, powerful tool for controlling the product chirality and optical yield in asym. photochem.
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  11. 11
    Inoue, Y.; Matsushima, E.; Wada, T. Pressure and Temperature Control of Product Chirality in Asymmetric Photochemistry. Enantiodifferentiating Photoisomerization of Cyclooctene Sensitized by Chiral Benezenepolycarboxylates. J. Am. Chem. Soc. 1998, 120, 10687– 10696,  DOI: 10.1021/ja981929a
    [ACS Full Text ACS Full Text], [CAS], Google Scholar
    11
    Pressure and temperature control of product chirality in asymmetric photochemistry - Enantiodifferentiating photoisomerization of cyclooctene sensitized by chiral benzenepolycarboxylates
    Inoue, Yoshihisa; Matsushima, Eiji; Wada, Takehiko
    Journal of the American Chemical Society (1998), 120 (41), 10687-10696CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)
    Pressure effects upon asym. photosensitization have been investigated for the first time in the enantiodifferentiating Z-E photoisomerization of cyclooctene (1), sensitized by chiral arom. esters (2-7). The product's enantiomeric excess (ee) and E/Z ratio were crit. functions of the applied pressure, exhibiting an unprecedented switching of the product chirality. Depending upon the chiral sensitizer employed, the differential activation vol. (ΔΔV⧧) varies widely from -3.7 to +5.6 cm3 mol-1, which is unexpectedly large for an enantiodifferentiation in the excited state. However, the ΔΔV⧧ values obtained do not correlate with the differential activation enthalpy (ΔΔH⧧) or entropy (ΔΔS⧧) obtained from temp.-dependence studies, indicating that pressure and temp. function as independent perturbants for the photoenantiodifferentiation process. Further investigations on the pressure dependence of ee at low temps. enable us to construct the first three-dimensional diagram that correlates the product's ee with pressure and temp. changes. The combined effects of temp. and pressure provide us with a versatile tool for the multidimensional control of asym. photochem. reactions, in which we can switch and/or enhance the product chirality at more readily accessible temps. and pressures, without using antipodal sensitizers.
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  12. 12
    (a) Weber, G.; Tanaka, F.; Okamoto, B. Y.; Drickamer, H. G. The Effect of Pressure on the Molecular Complex of Isoalloxazine and Adenine. Proc. Natl. Acad. Sci. U.S.A 1974, 71, 1264– 1266,  DOI: 10.1073/pnas.71.4.1264
    [Crossref], [PubMed], [CAS], Google Scholar
    12a
    Effect of pressure on the molecular complex of isoalloxazine and adenine
    Weber, Gregorio; Tanaka, Fumio; Okamoto, Byron Y.; Drickamer, Harry G.
    Proceedings of the National Academy of Sciences of the United States of America (1974), 71 (4), 1264-6CODEN: PNASA6; ISSN:0027-8424.
    The effect of pressure to 10 kilobars on the fluorescence characteristics of FMN [146-17-8], FAD [146-14-5], and on complexes of FMN with AMP [61-19-8], and with I- [20461-54-5] was studied. The properties measured include peak location, fluorescence yield, and lifetime. The equil. const. K and the rate const. k+* for complex formation were evaluated as a function of pressure. The pressure dependence of these coeffs. shows that the vol. of the system decreases upon complex formation and that there is an expansion upon formation of the activated complex. The implications of these results for protein denaturation are mentioned.
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    (b) Torgerson, P. M.; Drickamer, H. G.; Weber, G. Inclusion Complexes of Poly-β-cyclodextrin: A Model for Pressure Effects upon Ligand-Protein Complexes. Biochemistry 1979, 18, 3079– 3083,  DOI: 10.1021/bi00581a026
    [ACS Full Text ACS Full Text], [CAS], Google Scholar
    12b
    Inclusion complexes of poly-β-cyclodextrin: a model for pressure effects upon ligand-protein complexes
    Torgerson, P. M.; Drickame, H. G.; Weber, Gregorio
    Biochemistry (1979), 18 (14), 3079-83CODEN: BICHAW; ISSN:0006-2960.
    Certain protein-ligand complexes are destabilized by application of pressures of the order of 5-10 kbar, whereas others are stabilized. This divergent behavior is attributed to differences in compressibility of the protein binding sites. Pressure-stabilized binding is thought to be characteristic of soft binding sites, sites in which rotation about backbone bonds permits redn. of the site dimensions under pressure. In contradistinction, hard binding sites do not decrease their size when pressure is applied. As a model for this latter kind, the changes in equil. with pressure were measured for complexes of poly-β-cyclodextrin with 2 fluorescent probes: 8-anilinonaphthalene-1-sulfonate and 6-propionyl-2-(dimethylamino)naphthalene. The std. vol. change upon formation of the complexes at 1 atm. is similar in both (+9.3 mL/mol), and as expected, the incompressibility of the cyclodextrin rings results in a site from which the probes are dissocd. by pressure. On the assumption of incompressibility of the binding site, the exptl. data permit the calcn. of pressure vs. vol. curves (compressibility curves) for the probes molecularly dispersed in water. These curves are in broad agreement with those of liq. aliph. and arom. hydrocarbons in the low-pressure range (1-4 kbar) but indicate a reduced compressibility at higher pressures. Considerations of relative compressibility offer a quant. alternative to the usual qual. discussion of the effects of high pressure upon protein in terms of the participation of hydrophobic and other bonds.
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    (c) Williams, R. K. Pressure Enhancement of Charge-Trasfer Complexing of 1-Methyl-3-(carbomethoxy)pyridinium Cation and 8-Chlorotheophyllinate Anion in Aqueous Solution. J. Phys. Chem. 1981, 85, 1795– 1799,  DOI: 10.1021/j150613a007
    [ACS Full Text ACS Full Text], [CAS], Google Scholar
    12c
    Pressure enhancement of charge-transfer complexing of 1-methyl-3-(carbomethoxy)pyridinium cation and 8-chlorotheophyllinate anion in aqueous solution
    Williams, R. Kenneth
    Journal of Physical Chemistry (1981), 85 (13), 1795-9CODEN: JPCHAX; ISSN:0022-3654.
    Assocn. consts. were detd. for the title ions at 0.10-209.5 MPa. The apparent vol. change on assocn. is estd. to be -4.0 ± 0.5 cm3/mol, and the increment in compressibility is 0.0 Pa-1. No significant change in the increment in the extinction coeff. was obsd. The results are interpreted in terms of the vol. changes to be expected on assocn. due to an ion pairing, charge transfer, and the approach of arom. rings in water.
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    .
    (d) Letcher, T. M.; Mercer-Chalmers, J. D.; Kay, R. L. Volume changes in complex formation between crown ethers of cryptand-222 and alkali metals in various solvents. Pure Appl. Chem. 1994, 66, 419– 427,  DOI: 10.1351/pac199466030419
    [Crossref], [CAS], Google Scholar
    12d
    Volume changes in complex formation between crown ethers of cryptand-222 and alkali metals in various solvents
    Letcher, T. M.; Mercer-Chalmers, J. D.; Kay, R. L.
    Pure and Applied Chemistry (1994), 66 (3), 419-27CODEN: PACHAS; ISSN:0033-4545.
    The vol. changes ΔV∞ in crown ether or cryptand-222 + metal salt reactions are large. These reactions are interesting in that the metal ion is apparently enveloped by the larger org. mol. and as a result these measurements can shed light on the processes involved. ΔV∞ not only reflects the proposed simple mechanism but also is a measure of the electrostriction effect of the metal ion on the solvent.
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    (e) Isaacs, N. S.; Nichols, P. J.; Raston, C. L.; Sandova, C. A.; Young, D. J. Solution volume studies of a deep cavity inclusion complex of C60: [p-benzylcalix[5]arene ⊂ C60]. Chem. Commun. 1997, 1839– 1840,  DOI: 10.1039/a702200j
    [Crossref], [CAS], Google Scholar
    12e
    Solution volume studies of a deep cavity inclusion complex of C60: [p-benzylcalix[5]arene ⊂ C60]
    Isaacs, Neil S.; Nichols, Peter J.; Raston, Colin L.; Sandova, Christian A.; Young, David J.
    Chemical Communications (Cambridge) (1997), (19), 1839-1840CODEN: CHCOFS; ISSN:1359-7345. (Royal Society of Chemistry)
    Mol. complexation of C60 with p-benzylcalix[5]arene in toluene is assocd. with a partial molar volume change of +195 cm3 mol-1 which is consistent with the displacement of two toluene mols. from the cavity of the calixarene.
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    .
    (f) Abou-Hamdan, A.; Bugnon, P.; Saudan, C.; Lye, P. G.; Merbach, A. E. High-Pressure Studies as a Novel Approach in Determining Inclusion Mechanisms: Thermodynamics and Kinetics of the Host-Guest Interactions for α-Cyclodextrin Complexes. J. Am. Chem. Soc. 2000, 122, 592– 602,  DOI: 10.1021/ja993139m
    [ACS Full Text ACS Full Text], [CAS], Google Scholar
    12f
    High-Pressure Studies as a Novel Approach in Determining Inclusion Mechanisms: Thermodynamics and Kinetics of the Host-Guest Interactions for α-Cyclodextrin Complexes
    Abou-Hamdan, Amira; Bugnon, Pascal; Saudan, Christophe; Lye, Peter G.; Merbach, Andre E.
    Journal of the American Chemical Society (2000), 122 (4), 592-602CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)
    The first vol. profiles for complex formation of α-cyclodextrins (α-CD) with di-Ph azo dyes (S) are presented as a new approach in understanding inclusion phenomena. The following dyes were selected: sodium 4-(4-diethylaminophenylazo)benzenesulfonate, sodium 4-(3-carboxy-4-hydroxy-5-methylphenylazo)benzenesulfonate, sodium 4-(4-hydroxy-3,5-dimethylphenylazo)benzenesulfonate, and sodium 2-hydroxy-3-methyl-5-(4-sulfamoylphenylazo)benzoate. The behavior of the dyes alone was first studied in aq. solns. to rule out any competition reaction. Under the exptl. conditions used for the stopped-flow kinetic studies, it has been proved that only monomeric species are present (no aggregation of the dye is formed by π-π stacking interactions). NMR expts. and kinetic evidences have shown that only directional binding of the dye via the sulfonate/sulfonamide group through the wide rim of the α-cyclodextrin was possible. The 1:1 complex was the only stoichiometric species formed. The inclusion reactions for the four selected dyes were characterized by a two-step kinetics described by a first fast step that yields the intermediate, S·α-CD*, followed by a slower rearrangement to form the final complex, S·α-CD. 2D NMR expts. served for a mol. dynamics calcn. leading to a structural representation of the intermediate and final complexes. An interpretation of the vol. profiles obtained from high-pressure stopped-flow kinetic expts. have not only confirmed the so far proposed mechanisms based on "classical" kinetic investigations but offered a new focus on the inclusion process. The inclusion mechanism can be summarized now as follows: the complexation begins with an encounter of the dye and α-cyclodextrin mainly due to hydrophobic interactions followed by a partial desolvation of the entering head of the dye. The latter interacts with the two "activated" inner water mols. of the free host and their complete release is delayed by the primary hydroxy group barrier of the α-CD. At this first transition state, a squeezed arrangement develops inside the cavity inducing a neg. activation vol. (ΔV1,f⧧ ≈ -8 to -24 cm3 mol-1). The subsequent intermediate is characterized by a total release of the two inner water mols. and interactions of the dye head with the primary hydroxy groups of the host in a trapped-like structure (ΔV1° ≈ -11 to -4 cm3 mol-1). The latter interactions and concurrent tail interactions with the secondary hydroxy groups of the host lead at different extents to a strained conformation of the host in the second transition state (ΔV2,f⧧ ≈ -2 to -16 cm3 mol-1). In the final complex, the head of the dye is totally rehydrated as it protrudes from the primary end of the host cavity which can now adopt a released conformation (ΔV2° ≈ +3 to +6 cm3 mol-1 vs +17 cm3 mol-1 for 1).
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    .
    (g) Saudan, C.; Dunand, F. A.; Abou-Hamdan, A.; Bugnon, P.; Lye, P. G.; Lincoln, S. F.; Merbach, A. E. A Model for Sequential Threading of α-Cyclodextrin onto a Guest: A Complete Thermodynamic and Kinetic Study in Water. J. Am. Chem. Soc. 2001, 123, 10290– 10298,  DOI: 10.1021/ja010946o
    [ACS Full Text ACS Full Text], [CAS], Google Scholar
    12g
    A Model for Sequential Threading of α-Cyclodextrin onto a Guest: A Complete Thermodynamic and Kinetic Study in Water
    Saudan, Christophe; Dunand, Frank A.; Abou-Hamdan, Amira; Bugnon, Pascal; Lye, Peter G.; Lincoln, Stephen F.; Merbach, Andre E.
    Journal of the American Chemical Society (2001), 123 (42), 10290-10298CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)
    The first variable-temp. and variable-pressure stopped-flow spectrophotometric study of the sequential threading of α-cyclodextrin (α-CD) onto the guest dye Mordant Orange 10, S, is reported. Complementary 1H one-dimensional (1D) variable-temp. kinetic studies and two-dimensional (2D) rotating-frame nOe spectroscopy (ROESY) and EXSY NMR studies are also reported. In aq. soln. at 298.2 K, the first α-CD threads onto S to form a 1:1 complex S·α-CD* with a forward rate const. k1,f = 15 200 ± 200 M-1 s-1 and dethreads with a reverse rate const. k1,r = 4.4 ± 0.3 s-1. Subsequently, S·α-CD* isomerizes to S·α-CD (k3,f = 0.158 ± 0.006 s-1, k3,f = 0.148 ± 0.006 s-1). This process can be viewed as a thermodynamically controlled mol. shuttle. A second α-CD threads onto S·α-CD* to form a 1:2 complex, S·(α-CD)2*, with k2,f = 98 ± 2 M-1 s-1 and k2,r = 0.032 ± 0.002 s-1. A second α-CD also threads onto S·α-CD to form another 1:2 complex, S·(α-CD)2, characterized by k4,f = 9640 ± 1800 M-1 s-1 and k4,r = 61 ± 6 s-1. Direct interconvertion between S·(α-CD)2* and S·(α-CD)2 was not detected; instead, they interconvert by dethreading the second α-CD and through the isomerization equil. between S·α-CD* and S·α-CD. The reaction vols., ΔV0, were found to be neg. for the first three equil. and pos. for the fourth equil. For the first three forward and reverse reactions, the vols. of activation are substantially more neg., indicating a compression of the transition state in comparison with the ground states. These data were used in conjunction with ΔH⧧, ΔH°, ΔS⧧, and ΔS° data to deduce the dominant mechanistic threading processes, which appear to be largely controlled by changes in hydration and van der Waals interactions, and possibly by conformational changes in both S and α-CD. The structure of the four complexes was deduced from 1H 2D ROESY NMR studies.
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    (h) Ruloff, R.; Seelbach, U. P.; Merbach, A. E.; Klärner, F.-G. Molecular tweezers as synthetic receptors: the effect of presssure and temperature on the formation of host-guest complexes. J. Phys. Org. Chem. 2002, 15, 189– 196,  DOI: 10.1002/poc.477
    [Crossref], [CAS], Google Scholar
    12h
    Molecular tweezers as synthetic receptors: the effect of pressure and temperature on the formation of host-guest complexes
    Ruloff, Robert; Seelbach, Uta P.; Merbach, Andre E.; Klarner, Frank-Gerrit
    Journal of Physical Organic Chemistry (2002), 15 (4), 189-196CODEN: JPOCEE; ISSN:0894-3230. (John Wiley & Sons Ltd.)
    For the formation of the supramol. complexes between the mol. tweezers and arom. guests the vols. of reaction ΔV were detd. from the pressure dependence of the assocn. consts. K by the use of high-pressure 1H NMR spectroscopy and the enthalpy ΔH and entropy ΔS of reaction from the temp. dependence of K. The small pressure dependence of K and, hence, the small variation of the reaction vols. around the zero value (ΔV ≈ 0 cm3 mol-1) clearly indicate that the contraction in vol. resulting from the host-guest assocn. is compensated for by the expansion in vol. resulting from the desolvation of the free host and guest which has to proceed during the complexation. The assocn. and desolvation are expected to have similar effects on ΔS compensating each other. The significant deviations of ΔS from the zero value are, however, good evidence that the size of ΔS not only depends on the processes mentioned above but moreover is influenced by other factors such as the conformational mobility of the guest mol. inside the receptor cavity.
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    (i) Yang, C.; Nakamura, A.; Fukuhara, G.; Origane, Y.; Mori, T.; Wada, T.; Inoue, Y. Pressure and Temperature-Controlled Enantiodifferentiating [4+4] Photocyclodimerization of 2-Anthracenecarboxylate Mediated by Secondary Face- and Skeleton-Modified γ-Cyclodextrins. J. Org. Chem. 2006, 71, 3126– 3136,  DOI: 10.1021/jo0601718
    [ACS Full Text ACS Full Text], [CAS], Google Scholar
    12i
    Pressure and Temperature-Controlled Enantio-Differentiating [4+4]-Photo-Cyclodimerization of 2-Anthracene-carboxylate Mediated by Secondary Face- and Skeleton-Modified γ-Cyclodextrins
    Yang, Cheng; Nakamura, Asao; Fukuhara, Gaku; Origane, Yumi; Mori, Tadashi; Wada, Takehiko; Inoue, Yoshihisa
    Journal of Organic Chemistry (2006), 71 (8), 3126-3136CODEN: JOCEAH; ISSN:0022-3263. (American Chemical Society)
    A series of secondary-face-substituted and skeleton-modified γ-cyclodextrins (γ-CDs) were prepd. as chiral hosts for enantio-differentiating [4+4]-photo-cyclodimerization reactions of 2-anthracene-carboxylic acid (AC). These γ-CD derivs. form stable ternary complexes with ACs, with altroside-bearing γ-CDs undergoing induced-fit conformational changes upon complexation, and the photo-cyclodimerization of AC was, thus, dramatically accelerated. The enantiomeric excess (ee) of anti-head-to-head cyclodimer was greatly enhanced in general with altroside-bearing γ-CDs. The influence of temp. and high pressure on the supra-mol. photo-chirogenic reaction has been investigated in depth. An enantiomeric excess as high as 71% was obtained for cyclodimer in the photo-cyclodimerization of AC mediated by 3A-amino-3A-deoxy-altro-γ-CD at 210 MPa and -21.5 °C.
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    (j) Yang, C.; Mori, T.; Origane, Y.; Ko, Y. H.; Selvapalam, N.; Kim, K.; Inoue, Y. Highly Stereoselective Photocyclodimerization of α-Cyclodextrin-Appended Anthracene Mediated by γ-Cyclodextrin and Cucurbit[8]uril: A Dramatic Steric Effect Operating Outside the Binding Site. J. Am. Chem. Soc. 2008, 130, 8574– 8575,  DOI: 10.1021/ja8032923
    [ACS Full Text ACS Full Text], [CAS], Google Scholar
    12j
    Highly Stereoselective Photocyclodimerization of α-Cyclodextrin-Appended Anthracene Mediated by γ-Cyclodextrin and Cucurbit[8]uril: A Dramatic Steric Effect Operating Outside the Binding Site
    Yang, Cheng; Mori, Tadashi; Origane, Yumi; Ko, Young Ho; Selvapalam, Narayanan; Kim, Kimoon; Inoue, Yoshihisa
    Journal of the American Chemical Society (2008), 130 (27), 8574-8575CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)
    Photocyclodimerization of α-cyclodextrin (CD)-appended anthracene was studied in the presence of γ-CD and cucurbit[8]uril (CB[8]) hosts to manipulate the stereo-differentiating photoreaction occurring inside the cavity by the bulky attachment located outside. The γ-CD-mediated photodimerization afforded the head-to-tail photodimers in 98% combined yield, in particular, the syn-head-to-tail photodimer of 91% ee in 68% yield, which are much greater than 32% ee and 44% yield obtained with unmodified anthracene carboxylate. The use of CB[8] also led to a striking inversion of the head-to-tail/head-to-head selectivity, affording exclusively the head-to-head photodimers in 99% combined yield.
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    (k) Kosaka, T.; Iwai, S.; Fukuhara, G.; Imai, Y.; Mori, T. Hydrostatic Pressure on Toroidal Interactinon and Propeller Chirality of Hexaarylbenzens: Explicit Solvent Effects on Differential Volumes in Methylcyclohexane and Hexane. Chem. Eur. J. 2019, 25, 2011– 2018,  DOI: 10.1002/chem.201804688
    [Crossref], [PubMed], [CAS], Google Scholar
    12k
    Hydrostatic Pressure on Toroidal Interaction and Propeller Chirality of Hexaarylbenzenes: Explicit Solvent Effects on Differential Volumes in Methylcyclohexane and Hexane
    Kosaka, Tomoyo; Iwai, Satono; Fukuhara, Gaku; Imai, Yoshitane; Mori, Tadashi
    Chemistry - A European Journal (2019), 25 (8), 2011-2018CODEN: CEUJED; ISSN:0947-6539. (Wiley-VCH Verlag GmbH & Co. KGaA)
    A unique and effective interaction between the peripheral arom. blades makes hexaarylbenzenes (HABs) attractive in fundamental research as well as for various applications such as mol. wires, sensors, and supramol. assemblies. The chiroptical responses of HABs are susceptible to environmental factors such as solvent and temp. owing to the dynamic conformational transitions between the conformers. In this study, pressure dependence on the propeller chiral HABs in two different solvents was studied in detail. The effective differential vols. for two different equil. were detd. by quant. analyses of CD spectra, affording very large differential vols. from the propeller to toroidal conformer (ΔVT-C) of +43 and +42 cm3 mol-1, for H2 and H6, resp., in methylcyclohexane. The value of H6 was further enhanced to +72 cm3 mol-1 in hexane, the largest value for the typical unimol. conformational change. Such a response of propeller chirality in HABs is expedient in designing more advanced piezo-sensitive materials.
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    (l) Yonezawa, S.; Sethy, R.; Fukuhara, G.; Kawai, T.; Nakashima, T. Pressure-dependent guest binding and release on a supramolecular polymer. Chem. Commun. 2019, 55, 5793– 5796,  DOI: 10.1039/C9CC02696G
    [Crossref], [PubMed], [CAS], Google Scholar
    12l
    Pressure-dependent guest binding and release on a supramolecular polymer
    Yonezawa, Shumpei; Sethy, Ramarani; Fukuhara, Gaku; Kawai, Tsuyoshi; Nakashima, Takuya
    Chemical Communications (Cambridge, United Kingdom) (2019), 55 (41), 5793-5796CODEN: CHCOFS; ISSN:1359-7345. (Royal Society of Chemistry)
    Chiral guest binding on a self-assembly of a bichromophoric naphthalenediimide (NDI) deriv. is modulated in response to pressure. The intermol. packing in the supramol. polymer is strengthened at high pressure, compressing the binding pockets and discharging the guest mols.
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  13. 13
    (a) Johnson, P. C.; Offen, H. W. Effect of Pressure on Pyrene Excimer Fluorescence in Toluene. J. Chem. Phys. 1972, 56, 1638– 1642,  DOI: 10.1063/1.1677418
    [Crossref], [CAS], Google Scholar
    13a
    Effect of pressure on pyrene excimer fluorescence in toluene
    Johnson, P. C.; Offen, H. W.
    Journal of Chemical Physics (1972), 56 (4), 1638-42CODEN: JCPSA6; ISSN:0021-9606.
    The pressure dependence of pyrene fluorescence in PhMe was measured to 10 kbar. The monomer and excimer fluorescence decay kinetics are analyzed to give the rate parameters for excimer formation, dissocn., and unimol. decay as a function of pressure at 296, 320, and 340°K. Activation parameters are evaluated both as a function of temp. and as a function of pressure. The pressure dependence of the assocn. is in one-to-one correspondence with the solvent viscosity. The rate of dissocn. is strongly inhibited by high pressures. The vol. change on excimer formation is -11 cm3/mole at 296°K. The enthalpy and free energy of excimer formation are -9.7 and -4.2 kcal/mole at 1 atm, and -3.6 and -6.7 kcal/mole at 10 kbar, resp.
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    (b) Rollinson, A. M.; Drickamer, H. G. High Pressure Study of Luminescence from Intramolecular CT Compounds. J. Chem. Phys. 1980, 73, 5981– 5996,  DOI: 10.1063/1.440132
    [Crossref], [CAS], Google Scholar
    13b
    High pressure study of luminescence from intramolecular CT compounds
    Rollinson, A. M.; Drickamer, H. G.
    Journal of Chemical Physics (1980), 73 (12), 5981-96CODEN: JCPSA6; ISSN:0021-9606.
    The effects of high pressure on the luminescence properties of 4 org. intramol. charge transfer compds. were investigated. The compds. were studied in a wide range of liq. and polymeric environments, and for 1 of the compds., the effect of chem. substitution was also examd. In general, an increase of pressure affects the luminescence in a way which is similar to an increase of solvent polarity. A single configuration coordinate model was used to interpret the luminescence in terms of excited state interactions. Three of the compds. exhibited only fluorescence; p-(9-anthryl)-dimethylaniline (ADMA), 6-propionyl-2-dimethylaminonaphthalene (PRODAN), and 1-anilino-8-naphthalenesulfonate (ANS). Fluorescence from the 1st 2 compds. in nonpolar media is attributed to an excited state relatively unaffected by the charge transfer process. In polar media, fluorescence is believed to originate from another excited state that possesses considerably charge transfer character, and whose energy is strongly influenced by solvent polarity. The 4th compd., nitroaniline, was studied in its 3 isomeric forms, with and without N-methylation. In addn. to affecting the phosphorescence and fluorescence of p-nitroaniline, pressure studies indicate that nπ* singlet and triplet states figure prominently in the radiative and nonradiative processes of o-nitroaniline and m-nitroaniline as well.
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    .
    (c) Hara, K.; Arase, T.; Osugi, J. Effect of High Pressure on Intramolecular Electron-Transfer Luminescence of 9,9′-Bianthryl in Different Solvents. J. Am. Chem. Soc. 1984, 106, 1968– 1972,  DOI: 10.1021/ja00319a012
    [ACS Full Text ACS Full Text], [CAS], Google Scholar
    13c
    Effect of high pressure on intramolecular electron-transfer luminescence of 9,9'-bianthryl in different solvents
    Hara, Kimihiko; Arase, Takuya; Osugi, Jiro
    Journal of the American Chemical Society (1984), 106 (7), 1968-72CODEN: JACSAT; ISSN:0002-7863.
    The effects of high pressure on the fluorescence from the intramol. electron-transfer state of 9,9'-bianthryl were investigated in different solvents. In low-viscosity solvents an increase of pressure affects the emission similarly to an increase of solvent polarity. In moderately viscous solvents the formation of the electron-transfer state is quenched as pressure is increased. In highly viscous solvents, as in glycerol, the emission is only from the locally excited state at atm. pressure, and no change except for peak shift is obsd. with pressure increase. Freezing of solvents at high pressure strictly quenches the formation of the electron-transfer state.
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    .
    (d) Hara, K.; Obara, K. Effect of Pressure on the Formation of the Intramolecular Excited Complex State in 4-(9-Anthrylmethyl)-N,N-dimethylaniline. Chem. Phys. Lett. 1985, 117, 96– 98,  DOI: 10.1016/0009-2614(85)80412-7
    [Crossref], [CAS], Google Scholar
    13d
    Effect of pressure on the formation of the intramolecular excited complex state in 4-(9-anthrylmethyl)-N,N-dimethylaniline
    Hara, Kimihiko; Obara, Kazuyuki
    Chemical Physics Letters (1985), 117 (1), 96-8CODEN: CHPLBC; ISSN:0009-2614.
    The formation of an intramol. excited complex state in 4-(9-anthrylmethyl)-N,N-dimethylaniline was investigated at high pressures. A change in the kinetics from thermodn. control to kinetic control was obsd. in Et ether solvent. In toluene, the process is kinetically controlled over the whole pressure range. Appearance of this process depends upon the solvent viscosity, suggesting a conformational change in the course of the formation of the excited complex state.
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    .
    (e) Hara, K.; Yano, H. High-Pressure Study on Intramolecular Excimer Formation of 1,3-Di-1-pyrenylpropane in Various Solvents. J. Am. Chem. Soc. 1988, 110, 1911– 1915,  DOI: 10.1021/ja00214a040
    [ACS Full Text ACS Full Text], [CAS], Google Scholar
    13e
    High-pressure study on intramolecular excimer formation of 1,3-di-1-pyrenylpropane in various solvents
    Hara, Kimihiko; Yano, Hiroyuki
    Journal of the American Chemical Society (1988), 110 (6), 1911-15CODEN: JACSAT; ISSN:0002-7863.
    Viscosity effects on intramol. excimer (IE) formation in the title compd. were examd. at high pressures in various solvents. IE formation depends strongly and exclusively on solvent viscosity, but is insensitive to solvent polarity. The rates of IE formation estd. from fluorescence quantum yields are represented as a unique function of solvent viscosity. A hindered-rotation model based on Kramers' theory was applied successfully. More general results without specific interaction of solvent were obtained. The intrinsic activation energy (15-18 kJ/mol), the intrinsic activation vol. (-2.5 cm3/mol), and the frequency for the top of the barrier of IE formation were detd.
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    .
    (f) Rettig, W.; Gilabert, E.; Rulliére, C. Pressure Dependence of Bicimer Formation in 4-Dimethylamino-4′-cyanostilbene and Model Compounds. Chem. Phys. Lett. 1994, 229, 127– 133,  DOI: 10.1016/0009-2614(94)01005-6
    [Crossref], [CAS], Google Scholar
    13f
    Pressure dependence of bicimer formation in 4-dimethylamino-4'-cyanostilbene and model compounds
    Rettig, W.; Gilabert, E.; Rulliere, C.
    Chemical Physics Letters (1994), 229 (1,2), 127-33CODEN: CHPLBC; ISSN:0009-2614. (Elsevier)
    4-Dimethylamino-4'-cyanostilbene and selectively bridged model compds. are investigated using ps-time-resolved absorption and fluorescence measurements. The formation kinetics of a bicimer species are compared in homologous alc. solvents at ambient pressure and as a function of high pressure, and the viscosity dependences are discussed.
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    .
    (g) Hara, K.; Kometani, N.; Kajimoto, O. High-Pressure Studies on the Excited-State Intramolecular Charge Transfer of 4-(N,N-Dimethylamino)triphenylphosphine in Alcohols. J. Phys. Chem. 1996, 100, 1488– 1493,  DOI: 10.1021/jp952270n
    [ACS Full Text ACS Full Text], [CAS], Google Scholar
    13g
    High-Pressure Studies on the Excited-State Intramolecular Charge Transfer of 4-(N,N-Dimethylamino)triphenylphosphine in Alcohols
    Hara, Kimihiko; Kometani, Noritsugu; Kajimoto, Okitsugu
    Journal of Physical Chemistry (1996), 100 (5), 1488-93CODEN: JPCHAX; ISSN:0022-3654. (American Chemical Society)
    The influence of solvent viscosity on the intramol. charge-transfer (CT)-state formation in the excited S1 state for 4-(N,N-dimethylamino) triphenylphosphine (DMATP) in alc. solvents has been investigated by measuring the steady-state and time-resolved fluorescence spectra at high pressures. The kinetic mechanism of the intramol. CT reaction has been examd. as a function of solvent shear viscosity. In the lower viscosity region the reaction is controlled by the solvent relaxation. With increasing pressure, the reaction path shifts toward the "high-viscosity regime" in which the mol. moves along the non-relaxed path on the free energy surface. The viscosity dependence of α equiv. 0.33, where α is the power law parameter, can be interpreted as the extreme value in which the reaction is controlled by the dynamic solvent effect due to intrinsic collisional interaction of barrier crossing. The coupling between the intramol. CT-state formation dynamics of DMATP and the solvent relaxation dynamics is discussed.
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    .
    (h) Ruan, K.; Tian, S.; Lange, R.; Balny, C. Pressure Effects on Tryptophan and Its Derivatives. Biochem. Biophys. Res. Commun. 2000, 269, 681– 686,  DOI: 10.1006/bbrc.2000.2345
    [Crossref], [PubMed], [CAS], Google Scholar
    13h
    Pressure Effects on Tryptophan and Its Derivatives
    Ruan, Kangcheng; Tian, Shaoming; Lange, Reinhard; Balny, Claude
    Biochemical and Biophysical Research Communications (2000), 269 (3), 681-686CODEN: BBRCA9; ISSN:0006-291X. (Academic Press)
    The high pressure effects on fluorescence of free tryptophan (Trp) and its derivs., N-acetyl-tryptophan (AT), N-acetyl-tryptophanamide (NATA), tryptophanamide (TA), and tryptophan, contg. 6-polypeptides in aq. soln., were investigated in a pressure range from 0.1 to 650 MPa. It was found by analyzing the center of spectral mass in the wavelength range from 300 to 450 nm that high pressure shifted the fluorescence spectra of all these species to red direction: 421 cm-1 for Trp, 305 cm-1 for AT, 310 cm-1 for NATA, 265 cm-1 for TA, and 220 cm-1 for single tryptophan contg. 6-polypeptides. All the fluorescence efficiencies (i.e., quantum yield) of the compds. were reduced with pressure except free tryptophan where its fluorescence efficiency was enhanced with pressure. Glycerol, ethanol, and pH obviously influenced the pressure effects on their fluorescence characteristics. Since the tryptophan fluorescence is usually used as a probe for protein structural investigation, these findings suggested that the intrinsic pressure effect on tryptophan (or its derivs.) must be taken in consideration to explain the phenomenon obsd. in high pressure study on biomols. when using the usual fluorospectroscopic approaches. In the present investigation, the mechanisms involved for pressure effects on tryptophan and its derivs. were explored and discussed. (c) 2000 Academic Press.
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    .
    (i) Alamiry, M. A. H.; Benniston, A. C.; Copley, G.; Elliott, K. J.; Harriman, A.; Stewart, B.; Zhi, Y.-G. A Molecular Rotor Based on an Unhindered Boron Dipyrromethene (Bodipy) Dye. Chem. Mater. 2008, 20, 4024– 4032,  DOI: 10.1021/cm800702c
    [ACS Full Text ACS Full Text], [CAS], Google Scholar
    13i
    A Molecular Rotor Based on an Unhindered Boron Dipyrromethene (Bodipy) Dye
    Alamiry, Mohammed A. H.; Benniston, Andrew C.; Copley, Graeme; Elliott, Kristopher J.; Harriman, Anthony; Stewart, Beverly; Zhi, Yong-Gang
    Chemistry of Materials (2008), 20 (12), 4024-4032CODEN: CMATEX; ISSN:0897-4756. (American Chemical Society)
    This work describes a fluorescent probe for following changes in the viscosity of the surrounding medium. The optical properties, fluorescence characteristics, and sensitivity to frictional forces with the surrounding medium are superior to the most commonly used mol. probe, namely dicyanovinyl julolidine. The photophys. properties of the target mol. have been recorded in a range of solvents under ambient conditions, over a wide temp. range, and as a function of applied pressure. The mechanism by which the probe responds to changes in local viscosity involves gyration of the meso-phenylene ring and accompanying distortion of the dipyrrin framework, as indicated by mol. dynamics simulations. Indeed, temp.-dependence measurements have established that the activation energy is small when the solvent viscosity is relatively low, but there is a turnover to strong activation control at very high viscosity. A small but definite solvent dependence appears when the viscosity is varied by the application of high pressures and this can be traced to differences in the elasticity of the surroundings. Unusually for such fluorescent rotors, there is no indication that the excited state involves charge-transfer interactions. The rotor also responds to changes in the polarizability of the solvent, as induced by changes in applied pressure, and to the extent of polymn. of a monomer. The various exptl. observations made at low viscosity are consistent with diffusive motion of the wave packet along the excited-state potential curve until finding a sink that strongly coupled to the highly distorted ground state.
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    .
    (j) Alamiry, M. A. H.; Bahaidarah, E.; Harriman, A.; Bura, T.; Ziessel, R. Fluorescent molecular rotors under pressure: synergistic effects of an inert polymer. RSC Adv. 2012, 2, 9851– 9859,  DOI: 10.1039/c2ra20786a
    [Crossref], [CAS], Google Scholar
    13j
    Fluorescent molecular rotors under pressure: synergistic effects of an inert polymer
    Alamiry, Mohammed A. H.; Bahaidarah, Effat; Harriman, Anthony; Bura, Thomas; Ziessel, Raymond
    RSC Advances (2012), 2 (26), 9851-9859CODEN: RSCACL; ISSN:2046-2069. (Royal Society of Chemistry)
    Sterically unhindered boron dipyrromethene dyes bearing aryl hydrocarbons at the meso position can function as fluorescent probes for monitoring changes in rheol. of the surrounding environment. The key aspect of such behavior relates to the ease of rotation of the aryl ring, which is set in part by frictional forces with nearby solvent mols. For the target dye under consideration here, gyration of the meso-phenylene ring shows a pronounced temp. dependence but only a modest sensitivity towards applied pressure. Changing the specific viscosity of the solvent by adding a linear polymer has but a small effect on the fluorescence yield of the dye under ambient conditions and thereby indicates that there is little contact between dye and polymer. Under pressure in the presence of polymer, the fluorescence yield increases dramatically and allows design of an effective fluorescence-based pressure sensor. The simplest explanation of this phenomenon has the polymer wrapping around the dye under pressure and curtailing the rotary action. In addn., it has to be considered that the inert polymer renders the chloroform solvent more susceptible to a pressure-induced increase in d. by minimizing electrostatic repulsion between chlorine lone pairs. In this respect, the polymer acts as a lubricant for compression of chloroform under pressure.
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    .
    (k) Hablot, D.; Ziessel, R.; Alamiry, M. A. H.; Bahraidah, E.; Harriman, A. Nanomechanical properties of molecular-scale bridges as visualised by intramolecular electronic energy transfer. Chem. Sci. 2013, 4, 444– 453,  DOI: 10.1039/C2SC21505E
    [Crossref], [CAS], Google Scholar
    13k
    Nanomechanical properties of molecular-scale bridges as visualized by intramolecular electronic energy transfer
    Hablot, Delphine; Ziessel, Raymond; Alamiry, Mohammed A. H.; Bahraidah, Effat; Harriman, Anthony
    Chemical Science (2013), 4 (1), 444-453CODEN: CSHCCN; ISSN:2041-6520. (Royal Society of Chemistry)
    A series of mol. dyads has been synthesized and fully characterized. These linear, donor-spacer-acceptor compds. comprise terminal dyes selected to exhibit intramol. electronic energy transfer (EET) along the mol. axis. The spacer is built by accretion of ethynylene-carborane units that give center-to-center sepn. distances of 38, 57, 76, 96, and 115 Å resp. along the series. The probability of one-way EET between terminals depends on the length of the spacer but also on temp. and applied pressure. Throughout the series, the derived EET parameters are well explained in terms of through-space interactions but the probability of EET is higher than predicted for the fully extended conformation except in a glassy matrix at low temp. The implication is that these spacers contract under ambient conditions, with the extent of longitudinal contraction increasing under pressure but decreasing as the temp. is lowered. Longer bridges are more susceptible to such distortion, which is considered to resemble a concertina effect caused by out-of-plane bending of individual subunits. The dynamics of EET can be used to est. the strain energy assocd. with mol. contraction, the amt. of work done in effecting the structural change and the Young's modulus for the bridge.
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    .
    (l) Suhina, T.; Weber, B.; Carpentier, C. E.; Lorincz, K.; Schall, P.; Bonn, D.; Brouwer, A. M. Fluorescence Microscopy Visualization of Contacts Between Objects. Angew. Chem., Int. Ed. 2015, 54, 3688– 3691,  DOI: 10.1002/anie.201410240
    [Crossref], [CAS], Google Scholar
    13l
    Fluorescence Microscopy Visualization of Contacts Between Objects
    Suhina, Tomislav; Weber, Bart; Carpentier, Chantal E.; Lorincz, Kinga; Schall, Peter; Bonn, Daniel; Brouwer, Albert M.
    Angewandte Chemie, International Edition (2015), 54 (12), 3688-3691CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)
    The area of contact between two objects was detected by using the strong enhancement of the fluorescence of rigidochromic probe mols. attached to one of the surfaces. Confinement of the mols. suppresses nonradiative decay and turns on the fluorescence. The approach is demonstrated by imaging of the contact area of a plastic sphere in contact with a flat glass surface. Our results agree excellently with the prediction of Hertz's classical theory based on elastic deformation.
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    .
    (m) Sagara, Y.; Tamaoki, N.; Fukuhara, G. Cyclophane-Based Fluorescence Tuning Induced by Hydrostatic Pressure Changes. ChemPhotoChem 2018, 2, 959– 963,  DOI: 10.1002/cptc.201800163
    [Crossref], [CAS], Google Scholar
    13m
    Cyclophane-Based Fluorescence Tuning Induced by Hydrostatic Pressure Changes
    Sagara, Yoshimitsu; Tamaoki, Nobuyuki; Fukuhara, Gaku
    ChemPhotoChem (2018), 2 (11), 959-963CODEN: CHEMYH ISSN:. (Wiley-VCH Verlag GmbH & Co. KGaA)
    In contrast to a std. steady fluorescence intensity increase of a chloroform soln. of a linear chromophore unit under high pressure, a fluorescent cyclophane soln. shows significant fluorescence quenching under elevated pressure. A pressure-induced enhancement of the formation of an intramol. π-stacked conformation is proposed to be responsible.
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    .
    (n) Takeda, Y.; Mizuno, H.; Okada, Y.; Okazaki, M.; Minakata, S.; Penfold, T.; Fukuhara, G. Hydrostatic Pressure-Controlled Ratiometric Luminescence Responses of a Dibenzo[a,j]phenazine-Cored Mechanoluminophore. ChemPhotoChem 2019, 3, 1203– 1211,  DOI: 10.1002/cptc.201900190
    [Crossref], [CAS], Google Scholar
    13n
    Hydrostatic Pressure-Controlled Ratiometric Luminescence Responses of a Dibenzo[a,j]phenazine-Cored Mechanoluminophore
    Takeda, Youhei; Mizuno, Hiroaki; Okada, Yusuke; Okazaki, Masato; Minakata, Satoshi; Penfold, Thomas; Fukuhara, Gaku
    ChemPhotoChem (2019), 3 (12), 1203-1211CODEN: CHEMYH ISSN:. (Wiley-VCH Verlag GmbH & Co. KGaA)
    Understanding changes in excited state properties under the influence of an external stimulus, such as pressure or temp., is important in the context of optimizing mol. components for a no. of applications including sensors and imaging reagents. Herein, we use UV/Vis absorption, fluorescence and excitation spectroscopies and fluorescence lifetime measurements supported by calcns. to probe the effect of hydrostatic pressure on the excited state characteristics of a conformationally-divergent mechanochromic compd. PTZ-DBPHZ (contg. two phenothiazine moieties attached to a dibenzo[a,j]phenazine core) in toluene and methylcyclohexane. We demonstrate that hydrostatic pressure can be used to manipulate the equil. between excited state conformers. This work provides new perspectives for mechanoresponsive materials and as an attractive alternative to conventional ratiometric sensors.
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  14. 14
    Reichardt, C.; Welton, T. Solvents and Solvent Effects in Organic Chemistry; Wiley-VCH: Weinheim, 2011.
    Google Scholar
    There is no corresponding record for this reference.
  15. 15
    Reichardt, C. Solvatochromic Dyes as Solvent Polarity Indicators. Chem. Rev. 1994, 94, 2319– 2358,  DOI: 10.1021/cr00032a005
    [ACS Full Text ACS Full Text], [CAS], Google Scholar
    15
    Solvatochromic Dyes as Solvent Polarity Indicators
    Reichardt, Christian
    Chemical Reviews (Washington, DC, United States) (1994), 94 (8), 2319-58CODEN: CHREAY; ISSN:0009-2665.
    This review with 345 refs. compiles pos. and neg. solvatochromic compds. which have been used to establish empirical scales of solvent polarity by means of UV/visible/near-IR spectroscopic measurements in soln. with particular emphasis on the ET(30) scale derived from neg. solvatochromic pyridinium N-phenolate betaine dyes. A discussion is presented on the concept of solvent polarity and how empirical parameters of solvent polarity can be derived and understood in the framework of linear free-energy relationships.
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  16. 16
    Takagi, T.; Teranishi, H. Refractive Index of Liquids under High Pressure. J. Chem. Eng. Data 1982, 27, 16– 18,  DOI: 10.1021/je00027a003
    [ACS Full Text ACS Full Text], [CAS], Google Scholar
    16
    Refractive index of liquids under high pressure
    Takagi, Toshiharu; Teranishi, Hiroshi
    Journal of Chemical and Engineering Data (1982), 27 (1), 16-18CODEN: JCEAAX; ISSN:0021-9568.
    In order to measure the variation of the n of liqs. with pressure up to 50 MPa, a Michelson-type interferometer for 632.8-nm light is constructed. The pressure variations of the refractive indexes for mesitylene, benzene, and CCl4 which were measured and reported in the literature confirm the reliability of the interferometer. Measurements are performed on benzene, PhMe, PhCl, and PhNO2 at several temps. and pressures up to 50 MPa, with an estd. accuracy of better than ±0.00008.
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  17. 17
    Bovey, F. A.; Yanari, S. S. Effect of Solvent Polarizality on the Ultra-Violet Spectral Shifts of Aromatic Compounds. Nature 1960, 186, 1042– 1044,  DOI: 10.1038/1861042a0
    [Crossref], [CAS], Google Scholar
    17
    Effect of solvent polarizability on the ultraviolet spectral shifts of aromatic compounds
    Bovey, F. A.; Yanari, S. S.
    Nature (London, United Kingdom) (1960), 186 (), 1042-4CODEN: NATUAS; ISSN:0028-0836.
    The shift of the optical spectral max. of absorbing solutes, Δλ (= λs - λ0, where λs and λ0 are the wave lengths of max. absorption in soln. and vapor phase, resp.) has been measured for C6H6, PhF, PhOH, and benzotrifluoride in perfluoropentane, cyclic perfluoro-C8-ether (manufd. by Minn. Mining and Manufg. Co.), Et2O, H2O, EtOH, iso-C8H18, CHCl3, CCl4, and petrolatum. No satisfactory math. relation between Δλ and n could be established and no agreement was found with the theoretical equations of Bayliss (CA 44, 9250h) or Longuet-Higgins and Pople (CA 51, 17439a).
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  18. 18
    (a) Rohrdanz, M. A.; Martins, K. M.; Herbert, J. M. A long-range-corrected density functional that performs well for both ground-state properties and time-dependent density functional theory excitation energies, including charge-transfer excited states. J. Chem. Phys. 2009, 130, 054112– 1-8,  DOI: 10.1063/1.3073302
    [Crossref], [PubMed], [CAS], Google Scholar
    18a
    A long-range-corrected density functional that performs well for both ground-state properties and time-dependent density functional theory excitation energies, including charge-transfer excited states
    Rohrdanz, Mary A.; Martins, Katie M.; Herbert, John M.
    Journal of Chemical Physics (2009), 130 (5), 054112/1-054112/8CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)
    We introduce a hybrid d. functional that asymptotically incorporates full Hartree-Fock exchange, based on the long-range-cor. exchange-hole model of Henderson et al. The performance of this functional, for ground-state properties and for vertical excitation energies within time-dependent d. functional theory, is systematically evaluated, and optimal values are detd. for the range-sepn. parameter, ω, and for the fraction of short-range Hartree-Fock exchange. We denote the new functional as LRC-ωPBEh, since it reduces to the std. PBEh hybrid functional (also known as PBE0 or PBE1PBE) for a certain choice of its two parameters. Upon optimization of these parameters against a set of ground- and excited-state benchmarks, the LRC-ωPBEh functional fulfills three important requirements: (i) It outperforms the PBEh hybrid functional for ground-state atomization energies and reaction barrier heights; (ii) it yields statistical errors comparable to PBEh for valence excitation energies in both small and medium-sized mols.; and (iii) its performance for charge-transfer excitations is comparable to its performance for valence excitations. LRC-ωPBEh, with the parameters detd. herein, is the first d. functional that satisfies all three criteria. Notably, short-range Hartree-Fock exchange appears to be necessary in order to obtain accurate ground-state properties and vertical excitation energies using the same value of ω. (c) 2009 American Institute of Physics.
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    .
    (b) Ditchfield, R.; Hehre, W. J.; Pople, J. A. Self-Consistent Molecular-Orbital Methods. IX. An Extended Gaussian-Type Basis for Molecular-Orbital Studies of Organic Molecules. J. Chem. Phys. 1971, 54, 724– 728,  DOI: 10.1063/1.1674902
    [Crossref], [CAS], Google Scholar
    18b
    Self-consistent molecular-orbital methods. IX. Extended Gaussian-type basis for molecular-orbital studies of organic molecules
    Ditchfield, R.; Hehre, Warren J.; Pople, John A.
    Journal of Chemical Physics (1971), 54 (2), 724-8CODEN: JCPSA6; ISSN:0021-9606.
    An extended basis set of at. functions expressed as fixed linear combinations of Gaussian functions is presented for H and the first-row atoms C to F. In this set. described as 4-31 G, each inner shell is represented by a single basis function taken as a sum of 4 Gaussians, and each valence orbital is split into inner and outer parts described by 3 and 1 Gaussian function, resp. The expansion coeffs. and Gaussian exponents are detd. by minimizing the total calcd. energy of the at. ground state. This basis set is then used in single-determinant MO studies of a group of small polyat. mols. Optimization of valence-shell scaling factors shows that considerable rescaling of at. functions occurs in mols., the largest effects being obsd. for H and C. However, the range of optimum scale factors for each atom is small enough to allow the selection of a std. mol. set. The use of this std. basis gives theoretical equil. geometries in reasonable agreement with expt.
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    .
    (c) Hehre, W. J.; Ditchfield, R.; Pople, J. A. Self—Consistent Molecular Orbital Methods. XII. Further Extensions of Gaussian—Type Basis Sets for Use in Molecular Orbital Studies of Organic Molecules. J. Chem. Phys. 1972, 56, 2257– 2261,  DOI: 10.1063/1.1677527
    [Crossref], [CAS], Google Scholar
    18c
    Self-consistent molecular orbital methods. XII. Further extensions of Gaussian-type basis sets for use in molecular orbital studies of organic molecules
    Hehre, W. J.; Ditchfield, R.; Pople, J. A.
    Journal of Chemical Physics (1972), 56 (5), 2257-61CODEN: JCPSA6; ISSN:0021-9606.
    Two extended basis sets (termed 5-31G and 6-31G) consisting of AO expressed as fixed linear combinations of Gaussian functions are presented for the 1st row atoms C to F. These basis functions are similar to the 4-31G set in that each valence shell is split into inner and outer parts described by 3 and 1 Gaussian function, resp. Inner shells are represented by a single basis function taken as a sum of 5 (5-31G) or 6 (6-31G) Guassians. Studies with a no. of polyat. mols. indicate a substantial lowering of calcd. total energies over the 4-31G set. Calcd. relative energies and equil. geometries do not appear to be altered significantly.
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    .
    (d) Shao, Y.; Gan, Z.; Epifanovsky, E.; Gilbert, A. T. B.; Wormit, M.; Kussmann, J.; Lange, A. W.; Behn, A.; Deng, J.; Feng, X.; Ghosh, D.; Goldey, M.; Horn, P. R.; Jacobson, L. D.; Kaliman, I.; Khaliullin, R. Z.; Kuś, T.; Landau, A.; Liu, J.; Proynov, E. I.; Rhee, Y. M.; Richard, R. M.; Rohrdanz, M. A.; Steele, R. P.; Sundstrom, E. J.; Woodcock, H. L.; Zimmerman, P. M.; Zuev, D.; Albrecht, B.; Alguire, E.; Austin, B.; Beran, G. J. O.; Bernard, Y. A.; Berquist, E.; Brandhorst, K.; Bravaya, K. B.; Brown, S. T.; Casanova, D.; Chang, C.-M.; Chen, Y.; Chien, S. H.; Closser, K. D.; Crittenden, D. L.; Diedenhofen, M.; DiStasio, R. A.; Do, H.; Dutoi, A. D.; Edgar, R. G.; Fatehi, S.; Fusti-Molnar, L.; Ghysels, A.; Golubeva-Zadorozhnaya, A.; Gomes, J.; Hanson-Heine, M. W. D.; Harbach, P. H. P.; Hauser, A. W.; Hohenstein, E. G.; Holden, Z. C.; Jagau, T.-C.; Ji, H.; Kaduk, B.; Khistyaev, K.; Kim, J.; Kim, J.; King, R. A.; Klunzinger, P.; Kosenkov, D.; Kowalczyk, T.; Krauter, C. M.; Lao, K. U.; Laurent, A. D.; Lawler, K. V.; Levchenko, S. V.; Lin, C. Y.; Liu, F.; Livshits, E.; Lochan, R. C.; Luenser, A.; Manohar, P.; Manzer, S. F.; Mao, S.-P.; Mardirossian, N.; Marenich, A. V.; Maurer, S. A.; Mayhall, N. J.; Neuscamman, E.; Oana, C. M.; Olivares-Amaya, R.; O’Neill, D. P.; Parkhill, J. A.; Perrine, T. M.; Peverati, R.; Prociuk, A.; Rehn, D. R.; Rosta, E.; Russ, N. J.; Sharada, S. M.; Sharma, S.; Small, D. W.; Sodt, A.; Stein, T.; Stück, D.; Su, Y.-C.; Thom, A. J. W.; Tsuchimochi, T.; Vanovschi, V.; Vogt, L.; Vydrov, O.; Wang, T.; Watson, M. A.; Wenzel, J.; White, A.; Williams, C. F.; Yang, J.; Yeganeh, S.; Yost, S. R.; You, Z.-Q.; Zhang, I. Y.; Zhang, X.; Zhao, Y.; Brooks, B. R.; Chan, G. K. L.; Chipman, D. M.; Cramer, C. J.; Goddard, W. A.; Gordon, M. S.; Hehre, W. J.; Klamt, A.; Schaefer, H. F.; Schmidt, M. W.; Sherrill, C. D.; Truhlar, D. G.; Warshel, A.; Xu, X.; Aspuru-Guzik, A.; Baer, R.; Bell, A. T.; Besley, N. A.; Chai, J.-D.; Dreuw, A.; Dunietz, B. D.; Furlani, T. R.; Gwaltney, S. R.; Hsu, C.-P.; Jung, Y.; Kong, J.; Lambrecht, D. S.; Liang, W.; Ochsenfeld, C.; Rassolov, V. A.; Slipchenko, L. V.; Subotnik, J. E.; Van Voorhis, T.; Herbert, J. M.; Krylov, A. I.; Gill, P. M. W.; Head-Gordon, M. Advances in molecular quantum chemistry contained in the Q-Chem 4 program package. Mol. Phys. 2015, 113, 184– 215,  DOI: 10.1080/00268976.2014.952696
    [Crossref], [CAS], Google Scholar
    18d
    Advances in molecular quantum chemistry contained in the Q-Chem 4 program package
    Shao, Yihan; Gan, Zhengting; Epifanovsky, Evgeny; Gilbert, Andrew T. B.; Wormit, Michael; Kussmann, Joerg; Lange, Adrian W.; Behn, Andrew; Deng, Jia; Feng, Xintian; Ghosh, Debashree; Goldey, Matthew; Horn, Paul R.; Jacobson, Leif D.; Kaliman, Ilya; Khaliullin, Rustam Z.; Kus, Tomasz; Landau, Arie; Liu, Jie; Proynov, Emil I.; Rhee, Young Min; Richard, Ryan M.; Rohrdanz, Mary A.; Steele, Ryan P.; Sundstrom, Eric J.; Woodcock, H. Lee, III; Zimmerman, Paul M.; Zuev, Dmitry; Albrecht, Ben; Alguire, Ethan; Austin, Brian; Beran, Gregory J. O.; Bernard, Yves A.; Berquist, Eric; Brandhorst, Kai; Bravaya, Ksenia B.; Brown, Shawn T.; Casanova, David; Chang, Chung-Min; Chen, Yunquing; Chien, Siu Hung; Closser, Kristina D.; Crittenden, Deborah L.; Diedenhofen, Michael; DiStasio, Robert A., Jr.; Do, Hainam; Dutoi, Anthony D.; Edgar, Richard G.; Fatehi, Shervin; Fusti-Molnar, Laszlo; Ghysels, An; Golubeva-Zadorozhnaya, Anna; Gomes, Joseph; Hanson-Heine, Magnus W. D.; Harbach, Philipp H. P.; Hauser, Andreas W.; Hohenstein, Edward G.; Holden, Zachary C.; Jagau, Thomas-C.; Ji, Hyunjun; Kaduk, Ben; Khistyaev, Kirill; Kim, Jaehoon; Kim, Jihan; King, Rollin A.; Klunzinger, Phil; Kosenkov, Dmytro; Kowalczyk, Tim; Krauter, Caroline M.; Lao, Ka Un; Laurent, Adele; Lawler, Keith V.; Levchenko, Sergey V.; Lin, Ching Yeh; Liu, Fenglai; Livshits, Ester; Lochan, Rohini C.; Luenser, Arne; Manohar, Prashant; Manzer, Samuel F.; Mao, Shan-Ping; Mardirossian, Narbe; Marenich, Aleksandr V.; Maurer, Simon A.; Mayhall, Nicholas J.; Neuscamman, Eric; Oana, C. Melania; Olivares-Amaya, Roberto; O'Neill, Darragh P.; Parkhill, John A.; Perrine, Trilisa M.; Peverati, Roberto; Prociuk, Alexander; Rehn, Dirk R.; Rosta, Edina; Russ, Nicholas J.; Sharada, Shaama M.; Sharma, Sandeep; Small, David W.; Sodt, Alexander; Stein, Tamar; Stuck, David; Su, Yu-Chuan; Thom, Alex J. W.; Tsuchimochi, Takashi; Vanovschi, Vitalii; Vogt, Leslie; Vydrov, Oleg; Wang, Tao; Watson, Mark A.; Wenzel, Jan; White, Alec; Williams, Christopher F.; Yang, Jun; Yeganeh, Sina; Yost, Shane R.; You, Zhi-Qiang; Zhang, Igor Ying; Zhang, Xing; Zhao, Yan; Brooks, Bernard R.; Chan, Garnet K. L.; Chipman, Daniel M.; Cramer, Christopher J.; Goddard, William A., III; Gordon, Mark S.; Hehre, Warren J.; Klamt, Andreas; Schaefer, Henry F., III; Schmidt, Michael W.; Sherrill, C. David; Truhlar, Donald G.; Warshel, Arieh; Xu, Xin; Aspuru-Guzik, Alan; Baer, Roi; Bell, Alexis T.; Besley, Nicholas A.; Chai, Jeng-Da; Dreuw, Andreas; Dunietz, Barry D.; Furlani, Thomas R.; Gwaltney, Steven R.; Hsu, Chao-Ping; Jung, Yousung; Kong, Jing; Lambrecht, Daniel S.; Liang, WanZhen; Ochsenfeld, Christian; Rassolov, Vitaly A.; Slipchenko, Lyudmila V.; Subotnik, Joseph E.; Van Voorhis, Troy; Herbert, John M.; Krylov, Anna I.; Gill, Peter M. W.; Head-Gordon, Martin
    Molecular Physics (2015), 113 (2), 184-215CODEN: MOPHAM; ISSN:0026-8976. (Taylor & Francis Ltd.)
    A review. A summary of the tech. advances that are incorporated in the fourth major release of the Q-Chem quantum chem. program is provided, covering approx. the last seven years. These include developments in d. functional theory methods and algorithms, NMR (NMR) property evaluation, coupled cluster and perturbation theories, methods for electronically excited and open-shell species, tools for treating extended environments, algorithms for walking on potential surfaces, anal. tools, energy and electron transfer modeling, parallel computing capabilities, and graphical user interfaces. In addn., a selection of example case studies that illustrate these capabilities is given. These include extensive benchmarks of the comparative accuracy of modern d. functionals for bonded and non-bonded interactions, tests of attenuated second order Moller-Plesset (MP2) methods for intermol. interactions, a variety of parallel performance benchmarks, and tests of the accuracy of implicit solvation models. Some specific chem. examples include calcns. on the strongly correlated Cr2 dimer, exploring zeolite-catalyzed ethane dehydrogenation, energy decompn. anal. of a charged ter-mol. complex arising from glycerol photoionisation, and natural transition orbitals for a Frenkel exciton state in a nine-unit model of a self-assembling nanotube.
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    .
    (e) Eng, J.; Laidlaw, B. A.; Penfold, T. J. On the geometry dependence of tuned-range separated hybrid functionals. J. Comp. Chem. 2019, 40, 2191– 2199,  DOI: 10.1002/jcc.25868
    [Crossref], [PubMed], [CAS], Google Scholar
    18e
    On the geometry dependence of tuned-ranged separated hybrid functionals
    Eng, Julien; Laidlaw, Beth A.; Penfold, Thomas J.
    Journal of Computational Chemistry (2019), 40 (25), 2191-2199CODEN: JCCHDD; ISSN:0192-8651. (John Wiley & Sons, Inc.)
    Mols. and materials that absorb and/or emit light form a central part of the daily lives. Consequently, a description of their excited-state properties plays a crucial role in designing new mols. and materials with enhanced properties. Due to its favorable balance between high computational efficiency and accuracy, time-dependent d. functional theory (TDDFT) is often a method of choice for characterizing these properties. However, within std. approxns. to the exchange-correlation functional, it remains challenging to achieve a balanced description of all excited states, esp. for those exhibiting charge-transfer (CT) characteristics. The authors have applied 2 approaches, namely, the optimal tuning and triplet tuning methods, for a nonempirical definition of range-sepd. functionals to improve the description of excited states within TDDFT. This is applied to study the CT properties of 2 thermally activated delayed fluorescence emitters, namely, PTZ-DBTO2 and TAT-3DBTO2. The authors demonstrate the connection between the 2 methods, the performance of each in the presence on multiple excited states of different characters and the geometry dependence of each method esp. relevant in the context of developing size-consistent potential energy surfaces. © 2019 Wiley Periodicals, Inc.
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    .
    (f) Eng, J.; Hagon, J.; Penfold, T. J. D-A3 TADF emitters: the role of the density of states for achieving faster triplet harvesting rates. J. Mater. Chem. C 2019, 7, 12942– 12952,  DOI: 10.1039/C9TC02561H
    [Crossref], [CAS], Google Scholar
    18f
    D-A3 TADF emitters: the role of the density of states for achieving faster triplet harvesting rates
    Eng, Julien; Hagon, Jerry; Penfold, Thomas James
    Journal of Materials Chemistry C: Materials for Optical and Electronic Devices (2019), 7 (41), 12942-12952CODEN: JMCCCX; ISSN:2050-7534. (Royal Society of Chemistry)
    The triplet harvesting rate in purely org. materials based upon Thermally Activated Delayed Fluorescence (TADF) is critically important for achieving high performance Org. Light Emitting Diodes (OLEDs). One of the major challenges that must be overcome in these materials is the weak spin orbit coupling which can lead to triplet harvesting rates that extend into the millisecond range. This causes poor roll-off in device efficiency at higher current densities. In this work, we study the excited state properties of a new TADF design strategy based upon the D-A3 approach. Using TAT-3DBTO2, composed of a rigid triazatruxene donor core with three dibenzothiophene-S,S-dioxide peripheral acceptors, we explain how exploiting the high d. of excited states and low lying conical intersections assocd. with this structure can achieve high-rates of triplet harvesting. However, we also demonstrate that excited state structural changes reduce the symmetry of the mol. and work against high triplet harvesting rates by causing localization of the excited state electronic structure and non-equivalence between the acceptors. Consequently, the fast initial reverse intersystem crossing (rISC) channels are replaced by undesirable slower rISC channels. Our results imply that it will be possible to engineer mols. where undesirable decay pathways are removed giving new perspectives for designing functional TADF mols.
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    .
    (g) Hirata, S.; Head-Gordon, M. Time-dependent density functional theory within the Tamm–Dancoff approximation. Chem. Phys. Lett. 1999, 314, 291– 299,  DOI: 10.1016/S0009-2614(99)01149-5
    [Crossref], [CAS], Google Scholar
    18g
    Time-dependent density functional theory within the Tamm-Dancoff approximation
    Hirata, S.; Head-Gordon, M.
    Chemical Physics Letters (1999), 314 (3,4), 291-299CODEN: CHPLBC; ISSN:0009-2614. (Elsevier Science B.V.)
    A computationally simple method for mol. excited states, namely, the Tamm-Dancoff approxn. to time-dependent d. functional theory, is proposed and implemented. This method yields excitation energies for several closed- and open-shell mols. that are essentially of the same quality as those obtained from time-dependent d. functional theory itself, when the same exchange-correlation functional is used.
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    .
    (h) Ufimtsev, I. S.; Martinez, T. J. Quantum Chemistry on Graphical Processing Units. 3. Analytical Energy Gradients, Geometry Optimization, and First Principles Molecular Dynamics. J. Chem. Theory Comput. 2009, 5, 2619– 2628,  DOI: 10.1021/ct9003004
    [ACS Full Text ACS Full Text], [CAS], Google Scholar
    18h
    Quantum Chemistry on Graphical Processing Units. 3. Analytical Energy Gradients, Geometry Optimization, and First Principles Molecular Dynamics
    Ufimtsev, Ivan S.; Martinez, Todd J.
    Journal of Chemical Theory and Computation (2009), 5 (10), 2619-2628CODEN: JCTCCE; ISSN:1549-9618. (American Chemical Society)
    We demonstrate that a video gaming machine contg. two consumer graphical cards can outpace a state-of-the-art quad-core processor workstation by a factor of more than 180× in Hartree-Fock energy + gradient calcns. Such performance makes it possible to run large scale Hartree-Fock and D. Functional Theory calcns., which typically require hundreds of traditional processor cores, on a single workstation. Benchmark Born-Oppenheimer mol. dynamics simulations are performed on two mol. systems using the 3-21G basis set - a hydronium ion solvated by 30 waters (94 atoms, 405 basis functions) and an aspartic acid mol. solvated by 147 waters (457 atoms, 2014 basis functions). Our GPU implementation can perform 27 ps/day and 0.7 ps/day of ab initio mol. dynamics simulation on a single desktop computer for these systems.
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    .
    (i) Perdew, J. P.; Wang, Y. Accurate and simple analytic representation of the electron-gas correlation energy. Phys. Rev. B: Condens. Matter Mater. Phys. 1992, 45, 13244– 13249,  DOI: 10.1103/PhysRevB.45.13244
    [Crossref], [PubMed], [CAS], Google Scholar
    18i
    Accurate and simple analytic representation of the electron-gas correlation energy
    Perdew; Wang
    Physical review. B, Condensed matter (1992), 45 (23), 13244-13249 ISSN:0163-1829.
    There is no expanded citation for this reference.
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    .
    (j) Perdew, J. P.; Burke, K.; Ernzerhof, M. Generalized Gradient Approximation Made Simple. Phys. Rev. Lett. 1996, 77, 3865– 3868,  DOI: 10.1103/PhysRevLett.77.3865
    [Crossref], [PubMed], [CAS], Google Scholar
    18j
    Generalized gradient approximation made simple
    Perdew, John P.; Burke, Kieron; Ernzerhof, Matthias
    Physical Review Letters (1996), 77 (18), 3865-3868CODEN: PRLTAO; ISSN:0031-9007. (American Physical Society)
    Generalized gradient approxns. (GGA's) for the exchange-correlation energy improve upon the local spin d. (LSD) description of atoms, mols., and solids. We present a simple derivation of a simple GGA, in which all parameters (other than those in LSD) are fundamental consts. Only general features of the detailed construction underlying the Perdew-Wang 1991 (PW91) GGA are invoked. Improvements over PW91 include an accurate description of the linear response of the uniform electron gas, correct behavior under uniform scaling, and a smoother potential.
    >> More from SciFinder ®
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    .
    (k) Binkley, J. S.; Pople, J. A.; Hehre, W. J. Self-consistent molecular orbital methods. 21. Small split-valence basis sets for first-row elements. J. Am. Chem. Soc. 1980, 102, 939– 947,  DOI: 10.1021/ja00523a008
    [ACS Full Text ACS Full Text], [CAS], Google Scholar
    18k
    Self-consistent molecular orbital methods. 21. Small split-valence basis sets for first-row elements
    Binkley, J. Stephen; Pople, John A.; Hehre, Warren J.
    Journal of the American Chemical Society (1980), 102 (3), 939-47CODEN: JACSAT; ISSN:0002-7863.
    Two new split-valence basis sets, termed 6-21G and 3-21G, are proposed for use in MO calcns. on mols. contg. first-row elements. The valence functions for the smaller representation (3-21G) were taken directly from the larger (6-21G), preventing their collapse inwards to make up for deficiencies in the inner-shell region. This is necessary to ensure a good description of bonding interactions which necessarily involve overlap of valence functions. Equil. geometries, vibrational frequencies, relative energies, and elec. dipole moments calcd. using the 3-21G basis set are nearly identical with those obtained from the larger 6-21G representation. Compared to expt. they are consistently superior to properties derived from the STO-3G minimal basis set, and of comparable quality to those obtained from the larger 4-21G and 4-31G representations. One notable exception is that the 4-31G basis set yields hydrogenation energies in significantly better agreement with expt. than those obtained from 3-21G. The 3-21G basis set comprises the same no. of primitive Gaussian functions as STO-3G (although nearly twice the no. of basis functions) and should be nearly as efficient computationally as that representation for applications which require evaluation of energy derivs. as well as the energy itself (e.g., detn. of equil. geometry and calcn. of vibrational frequencies). It is less costly to apply than either the 4-21G or 4-31G split-valence basis sets, and in those areas where the performance of the two is comparable it would appear to be the method of choice.
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    .
    (l) Gordon, M. S.; Binkley, J. S.; Pople, J. A.; Pietro, W. J.; Hehre, W. J. Self-consistent molecular-orbital methods. 22. Small split-valence basis sets for second-row elements. J. Am. Chem. Soc. 1982, 104, 2797– 2803,  DOI: 10.1021/ja00374a017
    [ACS Full Text ACS Full Text], [CAS], Google Scholar
    18l
    Self-consistent molecular-orbital methods. 22. Small split-valence basis sets for second-row elements
    Gordon, Mark S.; Binkley, J. Stephen; Pople, John A.; Pietro, William J.; Hehre, Warren J.
    Journal of the American Chemical Society (1982), 104 (10), 2797-803CODEN: JACSAT; ISSN:0002-7863.
    Two new split-valence basis sets, termed 6-21G and 3-21G (B. et. al., 1980) for MO calcns on 1st-row element compds. are extended through the 2nd row. Equil. geometries, vibrational frequencies, relative energies, and elec. dipole moments calcd. with the use of the 3-21G basis set for a no. of mols. contg. 2nd-row atoms are nearly identical with those obtained from the larger 6-21G representation. Compared to expt. they are consistently superior to properties derived from the STO-3G minimal basis set, and of comparable quality to those obtained from the large 4-31G split-valence representation. The 3-21G set is less costly to apply than the 4-31G basis set, and would appear to be the method of choice for split-valence level Hartree-Fock calcns. on moderately sized mols.
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    .
    (m) Grimme, S.; Antony, J.; Ehrlich, S.; Krieg, H. A consistent and accurate ab initio parametrization of density functional dispersion correction (DFT-D) for the 94 elements H-Pu. J. Chem. Phys. 2010, 132, 154104– 1-19,  DOI: 10.1063/1.3382344
    [Crossref], [PubMed], [CAS], Google Scholar
    18m
    A consistent and accurate ab initio parametrization of density functional dispersion correction (DFT-D) for the 94 elements H-Pu
    Grimme, Stefan; Antony, Jens; Ehrlich, Stephan; Krieg, Helge
    Journal of Chemical Physics (2010), 132 (15), 154104/1-154104/19CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)
    The method of dispersion correction as an add-on to std. Kohn-Sham d. functional theory (DFT-D) has been refined regarding higher accuracy, broader range of applicability, and less empiricism. The main new ingredients are atom-pairwise specific dispersion coeffs. and cutoff radii that are both computed from first principles. The coeffs. for new eighth-order dispersion terms are computed using established recursion relations. System (geometry) dependent information is used for the first time in a DFT-D type approach by employing the new concept of fractional coordination nos. (CN). They are used to interpolate between dispersion coeffs. of atoms in different chem. environments. The method only requires adjustment of two global parameters for each d. functional, is asymptotically exact for a gas of weakly interacting neutral atoms, and easily allows the computation of at. forces. Three-body nonadditivity terms are considered. The method has been assessed on std. benchmark sets for inter- and intramol. noncovalent interactions with a particular emphasis on a consistent description of light and heavy element systems. The mean abs. deviations for the S22 benchmark set of noncovalent interactions for 11 std. d. functionals decrease by 15%-40% compared to the previous (already accurate) DFT-D version. Spectacular improvements are found for a tripeptide-folding model and all tested metallic systems. The rectification of the long-range behavior and the use of more accurate C6 coeffs. also lead to a much better description of large (infinite) systems as shown for graphene sheets and the adsorption of benzene on an Ag(111) surface. For graphene it is found that the inclusion of three-body terms substantially (by about 10%) weakens the interlayer binding. We propose the revised DFT-D method as a general tool for the computation of the dispersion energy in mols. and solids of any kind with DFT and related (low-cost) electronic structure methods for large systems. (c) 2010 American Institute of Physics.
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    .
    (n) Grimme, S.; Ehrlich, S.; Goerigk, L. Effect of the damping function in dispersion corrected density functional theory. J. Comput. Chem. 2011, 32, 1456– 1465,  DOI: 10.1002/jcc.21759
    [Crossref], [PubMed], [CAS], Google Scholar
    18n
    Effect of the damping function in dispersion corrected density functional theory
    Grimme, Stefan; Ehrlich, Stephan; Goerigk, Lars
    Journal of Computational Chemistry (2011), 32 (7), 1456-1465CODEN: JCCHDD; ISSN:0192-8651. (John Wiley & Sons, Inc.)
    It is shown by an extensive benchmark on mol. energy data that the math. form of the damping function in DFT-D methods has only a minor impact on the quality of the results. For 12 different functionals, a std. "zero-damping" formula and rational damping to finite values for small interat. distances according to Becke and Johnson (BJ-damping) has been tested. The same (DFT-D3) scheme for the computation of the dispersion coeffs. is used. The BJ-damping requires one fit parameter more for each functional (three instead of two) but has the advantage of avoiding repulsive interat. forces at shorter distances. With BJ-damping better results for nonbonded distances and more clear effects of intramol. dispersion in four representative mol. structures are found. For the noncovalently-bonded structures in the S22 set, both schemes lead to very similar intermol. distances. For noncovalent interaction energies BJ-damping performs slightly better but both variants can be recommended in general. The exception to this is Hartree-Fock that can be recommended only in the BJ-variant and which is then close to the accuracy of cor. GGAs for non-covalent interactions. According to the thermodn. benchmarks BJ-damping is more accurate esp. for medium-range electron correlation problems and only small and practically insignificant double-counting effects are obsd. It seems to provide a phys. correct short-range behavior of correlation/dispersion even with unmodified std. functionals. In any case, the differences between the two methods are much smaller than the overall dispersion effect and often also smaller than the influence of the underlying d. functional. © 2011 Wiley Periodicals, Inc.; J. Comput. Chem., 2011.
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  19. 19
    Ayitou, A. J.; Fukuhara, G.; Kumarasamy, E.; Inoue, Y.; Sivaguru, J. Enantiospecific Photochemical Transformations under Elevated Pressure. Chem. - Eur. J. 2013, 19, 4327– 4334,  DOI: 10.1002/chem.201203665
    [Crossref], [PubMed], [CAS], Google Scholar
    19
    Enantiospecific Photochemical Transformations under Elevated Pressure
    Ayitou, Anoklase J.-L.; Fukuhara, Gaku; Kumarasamy, Elango; Inoue, Yoshihisa; Sivaguru, J.
    Chemistry - A European Journal (2013), 19 (13), 4327-4334CODEN: CEUJED; ISSN:0947-6539. (Wiley-VCH Verlag GmbH & Co. KGaA)
    Enantiospecific axial-to-point chiral transfer in light-induced transformations was efficient under elevated pressure at high temps. Model photoreactions with atropisomeric compds. showed higher enantioselectivity in the photoproducts under elevated pressure. The ee values in the photoproducts were rationalized based on the increased stability of optically pure atropisomeric compds. at elevated pressure, even at high temps.
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  • Abstract

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    Figure 1

    Figure 1. Chemical structure of Reichardt’s dye (1) and definitions of the angles τi.

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    Figure 2

    Figure 2. UV/vis spectra of compound 1 in ethyl acetate (158 μM) at 0.1, 20, 40, 60, 80, 100, 120, 140, 160, 180, 200, 220, 240, 260, 280, and 300 MPa, measured in a high-pressure cell at room temperature.

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    Figure 3

    Figure 3. Plots of absorption maxima at (a) the C band (correlation coefficient r = 0.984) and (b) the A band (r = 0.963) in ethyl acetate.

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    Figure 4

    Figure 4. Theoretical absorption spectra. In blue: absorption at the ground-state minimum geometry. In red: averaged absorption over 30 snapshot geometries taken from the AIMD propagation in the ground state. A bathochromic shift of δλ = 134 nm has been applied to the whole spectrum to align it on the experimental one. A broadening of Δ = 10 nm has been used.

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    Figure 5

    Figure 5. Difference of electronic densities between the states composing the main studied absorption bands and the ground state. When said band is comprised of several states, only one representative transition is shown. See Figure SI for a description of additional states. Red: loss of electronic density, blue: gain. The numbering of the state and its transition wavelength are shown below.

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    Figure 6

    Figure 6. Distribution of the angles (a) τ1, τ2, (b) τ11, τ21, and (c) τ12 and τ22 along the AIMD propagated in the ground state. When the distribution follows a normal law g(τi), this one is shown in black lines, where . ⟨τi⟩ and σi are reported in Table 2.

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    This article references 19 other publications.

    1. 1
      (a) Wang, B.; Anslyn, E. V., Eds.; Chemosensors: Principles, Strategies, and Applications; Wiley: Hoboken, 2011.
      [Crossref], Google Scholar
      There is no corresponding record for this reference.
      (b) Fukuhara, G. Polymer-based supramolecular sensing and application to chiral photochemistry. Polym. J. 2015, 47, 649– 655,  DOI: 10.1038/pj.2015.52
      [Crossref], [CAS], Google Scholar
      1b
      Polymer-based supramolecular sensing and application to chiral photochemistry
      Fukuhara, Gaku
      Polymer Journal (Tokyo, Japan) (2015), 47 (10), 649-655CODEN: POLJB8; ISSN:0032-3896. (NPG Nature Asia-Pacific)
      A review. Supramol. sensing using polymers is of particular significance not only for fundamental science but also for a no. of practical diagnostic applications because, upon interaction with target analytes, polymers are capable of amplifying the binding events and thus greatly enhance the signal gain. Hence, we proposed the construction of supramol. sensors based on chiral functional polymers, such as synthetic conjugated polymers and modified polysaccharides, which are responsive to biol. important chiral materials and saccharides. The present strategy using polymer hosts that behave very differently from those commonly employed in conventional chemosensors is based on the chirality or mol. information propagation and amplification in the polymer chains. By exploiting the knowledge and techniques obtained from the polymer-based supramol. sensing of bio-related materials, we have expanded the research to photochem. asym. synthesis, or 'photochirogenesis,' which provides ecol. benign yet versatile routes to optically active compds. via electronically excited states and is also one of the most attractive and challenging topics in current chem. In this review, the author highlights polymer-based supramol. sensing and application to photochirogenesis with recent examples.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhs1SlurrK&md5=b073d02d5e483cf6952881cb504c7d6d
      .
      (c) Fukuhara, G. Allosteric signal-amplification sensing with polymer-based supramolecular hosts. J. Incl. Phenom. Macrocycl. Chem. 2019, 93, 127– 143,  DOI: 10.1007/s10847-019-00881-2
      [Crossref], Google Scholar
      There is no corresponding record for this reference.
    2. 2
      (a) Tamura, Z.; Terada, R.; Ohno, K.; Maeda, M. Features of Phenolsulfonphthalein and Phenolphthalein Substituted at All Ortho-Positions of Phenols with Bromine. Anal. Sci. 1999, 15, 339– 342,  DOI: 10.2116/analsci.15.339
      [Crossref], [CAS], Google Scholar
      2a
      Features of phenolsulfonphthalein and phenolphthalein substituted at all ortho-positions of phenols with bromine
      Tamura, Zenzo; Terada, Rimi; Ohno, Kennichi; Maeda, Masako
      Analytical Sciences (1999), 15 (4), 339-342CODEN: ANSCEN; ISSN:0910-6340. (Japan Society for Analytical Chemistry)
      The influence of bromination at all the ortho-positions of phenols on the features of phenolsulfonphthalein and phenolphthalein was investigated. The absorption spectra of Bromphenol Blue (H2BPS) in phosphate buffers demonstrated the complete opening of the lactone ring to form yellow HBPS- at pH 1 where pK2=3.8. The reaction of hydroxide ion with blue BPS2- to produce colorless BPS(OH)3- required heating where pK3=9. On the contrary, the spectra of 3',3'',5',5''-tetrabromophenolphthalein (H2BPP) demonstrated that the lactone ring was very stable. More than 99.5% of BPP2- species consisted of a colorless lactone possessing two isolated phenol groups where pK'1=6.0 and pK'2=6.8; the reaction of hydroxide ion with BPP2- to produce BPP(OH)3- was slow where pK3=10.3. These results indicate the increased acidity of phenols and the greater tendency of the central carbon atom to act as an electron acceptor.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1MXisVSntL8%253D&md5=66ebb9b56c747fdfa53a77f4ba0feabe
      .
      (b) Qu, F.; Li, N. B.; Luo, H. Q. Highly Sensitive Fluorescent and Colorimetric pH Sensor Based on Polyethylenimine-Capped Silver Nanoclusters. Langmuir 2013, 29, 1199– 1205,  DOI: 10.1021/la304558r
      [ACS Full Text ACS Full Text], [CAS], Google Scholar
      2b
      Highly Sensitive Fluorescent and Colorimetric pH Sensor Based on Polyethylenimine-Capped Silver Nanoclusters
      Qu, Fei; Li, Nian Bing; Luo, Hong Qun
      Langmuir (2013), 29 (4), 1199-1205CODEN: LANGD5; ISSN:0743-7463. (American Chemical Society)
      Silver nanoclusters capped by hyperbranched polyethylenimine (PEI) have been developed as a highly sensitive fluorescent and colorimetric pH sensor. The probe responds rapidly to pH fluctuations and has such absorption characteristics that the color changes from the colorless or a nearly colorless state to a colored state with increasing acidity, so PEI-capped Ag nanoclusters could be used as a color indicator for colorimetric pH detection. Quant., the fluorescence intensity of PEI-capped Ag nanoclusters exhibits a linear fashion over the pH range of 5.02-7.96 and increases by around 10-fold approx. with greater fluorescence at higher pH values. The repulsion development and conformational change of PEI with decreasing pH induce the aggregation of Ag nanoclusters, leading to an obvious color change and fluorescence quenching of Ag nanoclusters at low pH values. As expected, the pH probe is also sensitive to the different buffer solns., except for those contg. some anions that could react with Ag nanoclusters. Besides, the ionic strength of the buffers has a little influence on the pH-responsive behavior. The authors' pH sensor with nanoscaled phys. dimensions would be a promising candidate in the applications in biol., medical, and pharmaceutical fields.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXitVGjsg%253D%253D&md5=1157106375d555aee40fefab42fe7388
      .
      (c) Noh, J. Y.; Park, G. J.; Na, Y. J.; Jo, H. Y.; Lee, S. A.; Kim, C. A colorimetric “naked-eye” Cu(II) chemosensor and pH indicator in 100% aqueous solution. Dalton Trans. 2014, 43, 5652– 5656,  DOI: 10.1039/C3DT53637H
      [Crossref], [PubMed], [CAS], Google Scholar
      2c
      A colorimetric "naked-eye" Cu2+ chemosensor and pH indicator in 100% aqueous solution
      Noh, Jin Young; Park, Gyeong Jin; Na, Yu Jeong; Jo, Hyun Yong; Lee, Seul Ah; Kim, Cheal
      Dalton Transactions (2014), 43 (15), 5652-5656CODEN: DTARAF; ISSN:1477-9226. (Royal Society of Chemistry)
      A new, highly selective and sensitive colorimetric chemosensor for detection of Cu2+ ions in aq. soln. was developed. Receptor detected Cu2+ ions by changing its color from colorless to yellow. Also, the Cu2+-sensitive compd. was used as a colorimetric pH detector based on a color change due to 1-Cu2+ complex formation identifiable by the naked eye.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXktl2kurg%253D&md5=f5725c1d032c357b302eeaa81ebad125
    3. 3
      (a) Yeung, M. C.-L.; Yam, V. W.-W. Luminescent cation sensors: from host-guest chemistry, supramolecular chemistry to reaction-based mechanisms. Chem. Soc. Rev. 2015, 44, 4192– 4202,  DOI: 10.1039/C4CS00391H
      [Crossref], [PubMed], [CAS], Google Scholar
      3a
      Luminescent cation sensors: from host-guest chemistry, supramolecular chemistry to reaction-based mechanisms
      Yeung, Margaret Ching-Lam; Yam, Vivian Wing-Wah
      Chemical Society Reviews (2015), 44 (13), 4192-4202CODEN: CSRVBR; ISSN:0306-0012. (Royal Society of Chemistry)
      Other than traditional cation detection strategies, which are solely based on the ion-receptor complementarity, the extension of the concept of supramol. chem. and the mechanisms of irreversible analyte-specific reactions have also been integrated into the design of luminescent probes for the detection of cation in view of the exploration of highly sensitive and selective sensors. In this highlight, a versatile range of org. and organometallic architectures with cation-sensing capabilities based on the above mechanisms will be discussed.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXos1SntQ%253D%253D&md5=e12c4f4ba052e5531ec3c2f8dd0dfa22
      .
      (b) Busschaert, N.; Caltagirone, C.; Rossom, W. V.; Gale, P. A. Applications of Supramolecular Anion Recognition. Chem. Rev. 2015, 115, 8038– 8155,  DOI: 10.1021/acs.chemrev.5b00099
      [ACS Full Text ACS Full Text], [CAS], Google Scholar
      3b
      Applications of Supramolecular Anion Recognition
      Busschaert, Nathalie; Caltagirone, Claudia; Van Rossom, Wim; Gale, Philip A.
      Chemical Reviews (Washington, DC, United States) (2015), 115 (15), 8038-8155CODEN: CHREAY; ISSN:0009-2665. (American Chemical Society)
      A review. This review focuses on the applications of anion complexation in research over the past decade. This spans a wide range of areas, but for the purposes of this review are divided into sensing, extn., transport through lipid bilayers, the roles anions can play in the formation of mol. assemblies, and, finally, organocatalysis.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXovVSnsrg%253D&md5=e5ae6d6d1effcedacac74796c81ce485
    4. 4
      (a) Elosua, C.; Matias, I. R.; Bariain, C.; Arregui, F. J. Volatile Organic Compound Optical Fiber Sensors: A Review. Sensors 2006, 6, 1440– 1465,  DOI: 10.3390/s6111440
      [Crossref], [CAS], Google Scholar
      4a
      Volatile organic compound optical fiber sensors: a review
      Elosua, Cesar; Matias, Ignacio R.; Bariain, Candido; Arregui, Francisco J.
      Sensors (2006), 6 (11), 1440-1465CODEN: SENSC9; ISSN:1424-8220. (Molecular Diversity Preservation International)
      A review. Volatile org. compd. (VOC) detection is a topic of growing interest with applications in diverse fields, ranging from environmental uses to the food or chem. industries. Optical fiber VOC sensors offering new and interesting properties which overcame some of the inconveniences found on traditional gas sensors appeared over two decades ago. Thanks to its min. invasive nature and the advantages that optical fiber offers such as light wt., passive nature, low attenuation and the possibility of multiplexing, among others, these sensors are a real alternative to electronic ones in elec. noisy environments where electronic sensors cannot operate correctly. A classification of these devices was made according to the sensing mechanism and taking also into account the sensing materials or the different methods of fabrication. Some solns. already implemented for the detection of VOCs using optical fiber sensors will be described with detail.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28Xht1OntrjP&md5=bf75512eab32a0ba73182b21218dd31c
      .
      (b) Lee, M. Y.; Lee, H. R.; Park, C. H.; Han, S. G.; Oh, J. H. Organic Transistor-Based Chemical Sensors for Wearable Bioelectronics. Acc. Chem. Res. 2018, 51, 2829– 2838,  DOI: 10.1021/acs.accounts.8b00465
      [ACS Full Text ACS Full Text], [CAS], Google Scholar
      4b
      Organic Transistor-Based Chemical Sensors for Wearable Bioelectronics
      Lee, Moo Yeol; Lee, Hae Rang; Park, Cheol Hee; Han, Seul Gi; Oh, Joon Hak
      Accounts of Chemical Research (2018), 51 (11), 2829-2838CODEN: ACHRE4; ISSN:0001-4842. (American Chemical Society)
      A review. Bioelectronics for healthcare that monitor the health information on users in real time have stepped into the limelight as crucial electronic devices for the future due to the increased demand for "point-of-care" testing, which is defined as medical diagnostic testing at the time and place of patient care. In contrast to traditional diagnostic testing, which is generally conducted at medical institutions with diagnostic instruments and requires a long time for specimen anal., point-of-care testing can be accomplished personally at the bedside, and health information on users can be monitored in real time. Advances in materials science and device technol. have enabled next-generation electronics, including flexible, stretchable, and biocompatible electronic devices, bringing the commercialization of personalized healthcare devices increasingly within reach, e.g., wearable bioelectronics attached to the body that monitor the health information on users in real time. Addnl., the monitoring of harmful factors in the environment surrounding the user, such as air pollutants, chems., and UV light, is also important for health maintenance because such factors can have short- and long-term detrimental effects on the human body. The precise detection of chem. species from both the human body and the surrounding environment is crucial for personal health care because of the abundant information that such factors can provide when detg. a person's health condition. In this respect, sensor applications based on an org.-transistor platform have various advantages, including signal amplification, mol. design capability, low cost, and mech. robustness (e.g., flexibility and stretchability).This Account covers recent progress in org. transistor-based chem. sensors that detect various chem. species in the human body or the surrounding environment, which will be the core elements of wearable electronic devices. There has been considerable effort to develop high-performance chem. sensors based on org.-transistor platforms through material design and device engineering. Various exptl. approaches have been adopted to develop chem. sensors with high sensitivity, selectivity, and stability, including the synthesis of new materials, structural engineering, surface functionalization, and device engineering. In this Account, we first provide a brief introduction to the operating principles of transistor-based chem. sensors. Then we summarize the progress in the fabrication of transistor-based chem. sensors that detect chem. species from the human body (e.g., mols. in sweat, saliva, urine, tears, etc.). We then highlight examples of chem. sensors for detecting harmful chems. in the environment surrounding the user (e.g., nitrogen oxides, sulfur dioxide, volatile org. compds., liq.-phase org. solvents, and heavy metal ions). Finally, we conclude this Account with a perspective on the wearable bioelectronics, esp. focusing on org. electronic materials and devices.
      >> More from SciFinder ®
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    5. 5
      (a) Salinas, Y.; Martínez-Máñez, R.; Marcos, M. D.; Sancenón, F.; Costero, A. M.; Parra, M.; Gil, S. Optical chemosensors and reagents to detect explosives. Chem. Soc. Rev. 2012, 41, 1261– 1296,  DOI: 10.1039/C1CS15173H
      [Crossref], [PubMed], [CAS], Google Scholar
      5a
      Optical chemosensors and reagents to detect explosives
      Salinas, Yolanda; Martinez-Manez, Ramon; Marcos, Maria D.; Sancenon, Felix; Costero, Ana M.; Parra, Margarita; Gil, Salvador
      Chemical Society Reviews (2012), 41 (3), 1261-1296CODEN: CSRVBR; ISSN:0306-0012. (Royal Society of Chemistry)
      This crit. review is focused on examples reported from 1947 to 2010 related to the design of chromo-fluorogenic chemosensors and reagents for explosives (141 refs.).
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38Xns1yiuw%253D%253D&md5=f0e4e2f6e2cae4813ad6222a5a4305f9
      .
      (b) Schroeder, V.; Savagatrup, S.; He, M.; Lin, S.; Swager, T. M. Carbon Nanotube Chemical Sensors. Chem. Rev. 2019, 119, 599– 663,  DOI: 10.1021/acs.chemrev.8b00340
      [ACS Full Text ACS Full Text], [CAS], Google Scholar
      5b
      Carbon Nanotube Chemical Sensors
      Schroeder, Vera; Savagatrup, Suchol; He, Maggie; Lin, Sibo; Swager, Timothy M.
      Chemical Reviews (Washington, DC, United States) (2019), 119 (1), 599-663CODEN: CHREAY; ISSN:0009-2665. (American Chemical Society)
      Carbon nanotubes (CNTs) promise to advance a no. of real-world technologies. Of these applications, they are particularly attractive for uses in chem. sensors for environmental and health monitoring. However, chem. sensors based on CNTs are often lacking in selectivity, and the elucidation of their sensing mechanisms remains challenging. This review is a comprehensive description of the parameters that give rise to the sensing capabilities of CNT-based sensors and the application of CNT-based devices in chem. sensing. This review begins with the discussion of the sensing mechanisms in CNT-based devices, the chem. methods of CNT functionalization, architectures of sensors, performance parameters, and theor. models used to describe CNT sensors. It then discusses the expansive applications of CNT-based sensors to multiple areas including environmental monitoring, food and agriculture applications, biol. sensors, and national security. The discussion of each analyte focuses on the strategies used to impart selectivity and the mol. interactions between the selector and the analyte. Finally, the review concludes with a brief outlook over future developments in the field of chem. sensors and their prospects for commercialization.
      >> More from SciFinder ®
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    6. 6
      (a) Hembury, G. A.; Borovkov, V. V.; Inoue, Y. Chirality-Sensing Supramolecular Systems. Chem. Rev. 2008, 108, 1– 73,  DOI: 10.1021/cr050005k
      [ACS Full Text ACS Full Text], [CAS], Google Scholar
      6a
      Chirality-Sensing Supramolecular Systems
      Hembury, Guy A.; Borovkov, Victor V.; Inoue, Yoshihisa
      Chemical Reviews (Washington, DC, United States) (2008), 108 (1), 1-73CODEN: CHREAY; ISSN:0009-2665. (American Chemical Society)
      A review. A detailed understanding of the underpinning mechanisms and various influencing factors is of particular significance for smart control and further useful application of chiral supramol. science. Considering the vast body of literature on the subject of supramol. chirality generation (or chirogenesis), it is clear that the modes of chiral mol. communication are largely noncovalent in nature; primarily, these include attractive or repulsive electrostatic interactions, hydrogen bonding, van der Waals contacts, π-π interactions, and repulsive steric interactions, with these acting either independently or cooperatively to produce the obsd. chiral structures. Thus, it is with this in mind that we must approach the analyses of such dynamic supramol. chiral systems, with recent years showing a great increase in the sophistication with which research groups have been able to rationalize and apply supramol. principles to a large range of complex chiral assemblies.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXhsVCrsb7J&md5=22d667547e0889c5035b8944c9ca5a99
      .
      (b) Yashima, E.; Ousaka, N.; Taura, D.; Shimomura, K.; Ikai, T.; Maeda, K. Supramolecular Helical Systems: Helical Assemblies of Small Molecules, Foldamers, and Polymers with Chiral Amplification and Their Functions. Chem. Rev. 2016, 116, 13752– 13990,  DOI: 10.1021/acs.chemrev.6b00354
      [ACS Full Text ACS Full Text], [CAS], Google Scholar
      6b
      Supramolecular Helical Systems: Helical Assemblies of Small Molecules, Foldamers, and Polymers with Chiral Amplification and Their Functions
      Yashima, Eiji; Ousaka, Naoki; Taura, Daisuke; Shimomura, Kouhei; Ikai, Tomoyuki; Maeda, Katsuhiro
      Chemical Reviews (Washington, DC, United States) (2016), 116 (22), 13752-13990CODEN: CHREAY; ISSN:0009-2665. (American Chemical Society)
      A review. In this review, we describe the recent advances in supramol. helical assemblies formed from chiral and achiral small mols., oligomers (foldamers), and helical and nonhelical polymers from the viewpoints of their formations with unique chiral phenomena, such as amplification of chirality during the dynamic helically assembled processes, properties, and specific functionalities, some of which have not been obsd. in or achieved by biol. systems. In addn., a brief historical overview of the helical assemblies of small mols. and remarkable progress in the synthesis of single-stranded and multistranded helical foldamers and polymers, their properties, structures, and functions, mainly since 2009, will also be described.
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    7. 7
      (a) Kubota, R.; Hamachi, I. Protein recognition using synthetic small-molecular binders toward optical protein sensing in vitro and in live cells. Chem. Soc. Rev. 2015, 44, 4454– 4471,  DOI: 10.1039/C4CS00381K
      [Crossref], [PubMed], [CAS], Google Scholar
      7a
      Protein recognition using synthetic small-molecular binders toward optical protein sensing in vitro and in live cells
      Kubota, Ryou; Hamachi, Itaru
      Chemical Society Reviews (2015), 44 (13), 4454-4471CODEN: CSRVBR; ISSN:0306-0012. (Royal Society of Chemistry)
      Chem. sensing of amino acids, peptides, and proteins provides fruitful information to understand their biol. functions, as well as to develop the medical and technol. applications. To detect amino acids, peptides, and proteins in vitro and in vivo, vast kinds of chem. sensors including small synthetic binders/sensors, genetically-encoded fluorescent proteins and protein-based semisynthetic biosensors have been intensely investigated. This review deals with concepts, strategies, and applications of protein recognition and sensing using small synthetic binders/sensors, which are now actively studied but still in the early stage of investigation. The recognition strategies for peptides and proteins can be divided into three categories: (i) recognition of protein substructures, (ii) protein surface recognition, and (iii) protein sensing through protein-ligand interaction. Here, we overview representative examples of protein recognition and sensing, and discuss biol. or diagnostic applications such as potent inhibitors/modulators of protein-protein interactions.
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      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXltFWrs7s%253D&md5=8da36f0868752381c20a8ce7e95ad03a
      .
      (b) Zwang, T. J.; Tse, E. C. M.; Barton, J. K. Sensing DNA through DNA Charge Transport. ACS Chem. Biol. 2018, 13, 1799– 1809,  DOI: 10.1021/acschembio.8b00347
      [ACS Full Text ACS Full Text], [CAS], Google Scholar
      7b
      Sensing DNA through DNA Charge Transport
      Zwang, Theodore J.; Tse, Edmund C. M.; Barton, Jacqueline K.
      ACS Chemical Biology (2018), 13 (7), 1799-1809CODEN: ACBCCT; ISSN:1554-8929. (American Chemical Society)
      A review. DNA charge transport chem. involves the migration of charge over long mol. distances through the arom. base pair stack within the DNA helix. This migration depends upon the intimate coupling of bases stacked one with another, and hence any perturbation in that stacking, through base modifications or protein binding, can be sensed elec. In this review, the authors describe the many ways DNA charge transport chem. has been utilized to sense changes in DNA, including the presence of lesions, mismatches, DNA-binding proteins, protein activity, and even reactions under weak magnetic fields. Charge transport chem. is remarkable in its ability to sense the integrity of DNA.
      >> More from SciFinder ®
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    8. 8
      (a) Andón, F. T.; Fadeel, B. Programmed Cell Death: Molecular Mechanisms and Implications for Safety Assessment of Nanomaterials. Acc. Chem. Res. 2013, 46, 733– 742,  DOI: 10.1021/ar300020b
      [ACS Full Text ACS Full Text], [CAS], Google Scholar
      8a
      Programmed Cell Death: Molecular Mechanisms and Implications for Safety Assessment of Nanomaterials
      Andon, Fernando Torres; Fadeel, Bengt
      Accounts of Chemical Research (2013), 46 (3), 733-742CODEN: ACHRE4; ISSN:0001-4842. (American Chemical Society)
      A review. Engineered nanomaterials offer numerous and tantalizing opportunities in many sectors of society, including medicine. Needless to say, attention should also be paid to the potential for unexpected hazardous effects of these novel materials. To date, much of the nanotoxicol. literature has focused on the assessment of cell viability or cell death using primitive assays for the detection of plasma membrane integrity or mitochondrial function or assessment of cellular morphol. However, when assessing the cytotoxic effects of engineered nanomaterials, researchers need not only to consider whether cells are dead or alive but also to assess which of the numerous, highly specific pathways of cell death might be involved. Moreover, it is important to diagnose cell death based not only on morphol. markers but on the assessment and quantification of biochem. alterations specific to each form of cell death. In this Account, we provide a description of the three major forms of programmed cell death in mammalian cells: apoptosis, autophagic cell death, and regulated necrosis, sometimes referred to as necroptosis. Apoptosis can be activated via the extrinsic (death receptor-dependent) or via the intrinsic (mitochondria-dependent) route. Apoptotic cell death may or may not require the activation of cytosolic proteases known as caspases. Autophagy (self-eating) has an important homeostatic role in the cell, mediating the removal of dysfunctional or damaged organelles thereby allowing the recycling of cellular building blocks. However, unrestrained autophagy can kill cells. Studies in recent years have revealed that necrosis that depends on activation of the kinases RIP1 and RIP3 is a major form of programmed cell death with roles in development and immunity. We also discuss recent examples of the impact of engineered nanoparticles on the three different pathways of programmed cell death. For example, acute exposure of cells to carbon nanotubes (CNTs) can induce apoptosis whereas chronic exposure to CNTs may yield an apoptosis-resistant and tumorigenic phenotype in lung epithelial cells. Several reports show that nanoparticles, including polystyrene particles, are routed to the lysosomal compartment and trigger cell death through the destabilization of lysosomal membranes with engagement of the intrinsic apoptosis pathway. In addn., a no. of studies have demonstrated that nanomaterials such as CNTs, quantum dots, and gold nanoparticles can affect cellular autophagy. An improved understanding of the complexities of the nanomaterial-induced perturbation of different cell death pathways may allow for a better prediction of the consequences of human exposure.
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      .
      (b) Vadevoo, S. M. P.; Gurung, S.; Khan, F.; Haque, M. E.; Gunassekaran, G. R.; Chi, L.; Permpoon, U.; Lee, B. Peptide-based targeted therapeutics and apoptosis imaging probes for cancer therapy. Arch. Pharm. Res. 2019, 42, 150– 158,  DOI: 10.1007/s12272-019-01125-0
      [Crossref], [PubMed], [CAS], Google Scholar
      8b
      Peptide-based targeted therapeutics and apoptosis imaging probes for cancer therapy
      Vadevoo, Sri Murugan Poongkavithai; Gurung, Smriti; Khan, Fatima; Haque, Md. Enamul; Gunassekaran, Gowri Rangaswamy; Chi, Lianhua; Permpoon, Uttapol; Lee, Byungheon
      Archives of Pharmacal Research (2019), 42 (2), 150-158CODEN: APHRDQ; ISSN:0253-6269. (Pharmaceutical Society of Korea)
      A review. Peptides have advantages over antibodies in terms of deep tissue penetration, low immunogenicity, and cost-effective prodn., but they have short circulation time and poor stability in vivo. Peptides have been extensively used as targeting moieties for the delivery of drug-loaded nanoparticles and function as targeted therapeutics in cancer treatment. Here, we review peptides that are exploited as targeted therapeutics in cancer therapy and apoptosis imaging probes for the monitoring of treatment responses.
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    9. 9
      (a) Rekharsky, M. V.; Inoue, Y. Complexation Thermodynamics of Cyclodextrins. Chem. Rev. 1998, 98, 1875– 1917,  DOI: 10.1021/cr970015o
      [ACS Full Text ACS Full Text], [CAS], Google Scholar
      9a
      Complexation Thermodynamics of Cyclodextrins
      Rekharsky, Mikhail V.; Inoue, Yoshihisa
      Chemical Reviews (Washington, D. C.) (1998), 98 (5), 1875-1917CODEN: CHREAY; ISSN:0009-2665. (American Chemical Society)
      A review with 287 refs. aimed at expanding and updating the thermodn. data collected in the authors' previous papers. A better understanding of the nature of inclusion complexation by natural and modified cyclodextrins will be obtained.
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      .
      (b) Fukuhara, G.; Okazaki, T.; Lessi, M.; Nishijima, M.; Yang, C.; Mori, T.; Mele, A.; Bellina, F.; Chiappe, C.; Inoue, Y. Chiral ionic liquid-mediated photochirogenesis. Enantiodifferentiating photocyclodimerization of 2-anthracenecarboxylic acid. Org. Biomol. Chem. 2011, 9, 7105– 7112,  DOI: 10.1039/c1ob05716b
      [Crossref], [PubMed], [CAS], Google Scholar
      9b
      Chiral ionic liquid-mediated photochirogenesis. Enantiodifferentiating photocyclodimerization of 2-anthracenecarboxylic acid
      Fukuhara, Gaku; Okazaki, Takahiro; Lessi, Marco; Nishijima, Masaki; Yang, Cheng; Mori, Tadashi; Mele, Andrea; Bellina, Fabio; Chiappe, Cinzia; Inoue, Yoshihisa
      Organic & Biomolecular Chemistry (2011), 9 (20), 7105-7112CODEN: OBCRAK; ISSN:1477-0520. (Royal Society of Chemistry)
      Enantiodifferentiating photocyclodimerization of 2-anthracenecarboxylic acid (AC-H) and its lithium salt (AC-Li) in chiral ionic liq. (CIL), (R)-1-(2,3-dihydroxypropyl)-3-methylimidazolium acetate {[(R)-GLYMI][AcO]}, gave a mixt. of two head-to-tail (HT) and two head-to-head (HH) cyclodimers in HT/HH ratios of 1.3-1.7 (for AC-H) and 2.2-4.3 (for AC-Li) with low enantiomeric excesses (ee) of 0-3% for chiral syn-HT and anti-HH dimers. In contrast, irradn. of AC-H in an aq. soln., contg. cucurbit[8]uril (CB[8]) as a host and [(R)-GLYMI][AcO] or [(R)-GLYMI][Tf2N] as a modifier of CB portals, afforded the HH dimers in 91-99% selectivity, although the anti-HH dimer was totally racemic. Interestingly, irradn. of AC-H in a dichloromethane soln., contg. [(R)-GLYMI][AcO] as a chiral template, led to the formation of the HH-dimers in 98% selectivity with chiral anti-HH dimer in -14% ee, presumably by the dual ligation of two ACs to a CIL through electrostatic and hydrogen-bonding interactions.
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    10. 10
      (a) Inoue, Y.; Ikeda, H.; Kaneda, M.; Sumimura, T.; Everitt, S. R. L.; Wada, T. Entropy-Controlled Asymmetric Photochemistry: Switching of Product Chirality by Solvent. J. Am. Chem. Soc. 2000, 122, 406– 407,  DOI: 10.1021/ja993542t
      [ACS Full Text ACS Full Text], [CAS], Google Scholar
      10a
      Entropy-Controlled Asymmetric Photochemistry: Switching of Product Chirality by Solvent
      Inoue, Yoshihisa; Ikeda, Haruhiko; Kaneda, Masayuki; Sumimura, Toshiaki; Everitt, Simon R. L.; Wada, Takehiko
      Journal of the American Chemical Society (2000), 122 (2), 406-407CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)
      Enantiodifferentiating photoisomerization of achiral (Z)-cyclooctene (1Z) was studied in the presence of chiral sensitizers (optically active terpenoid or saccharide esters of benzenetetracarboxylic acid; 2a and 2b resp.) in pentane or di-Et ether at different temp. from -110 to 25° C. The reaction gave chiral (E)-cyclooctene (1E) with varying enantiomeric excess (ee) levels, in good to excellent chem. yields. Both chiral sensitizers afforded comparable ee values of approx. -5% at 25° C in both pentane and ether (the neg. sign indicates the predominant formation of the (R)-(-)-isomer), but gave distinctly different ee's at lower temps. When the menthyl ester 2a was used as a sensitizer, the ee of the product showed very similar temp. dependencies in both pentane and ether. Thus, the major enantiomer produced was switched from (R)- to (S)-1E at the equipodal temp., T0 = -19° C, and thereafter the ee continued to increase as the temp. was further reduced. In contrast, the use of the saccharide ester 2b led to opposite tendencies in the same solvents at lower temps. Thus, lowering the reaction temp. enhanced the prodn. of (R)-1E in pentane, but the enantioselectivity was switched to (S)-1E in ether, giving an ee of 73% at -110° C, which is the highest ee ever reported for an enantiodifferentiating photosensitization. To elucidate the nature of this important solvent effect, the authors performed enantiodifferentiating photosensitizations with 2b in several solvents, allowing them to investigate a range of different polarities.
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      .
      (b) Inoue, Y.; Wada, T.; Asaoka, S.; Sato, H.; Pete, J.-P. Photochirogenesis: multidimensional control of asymmetric photochemistry. Chem. Commun. 2000, 251– 259,  DOI: 10.1039/a905409j
      [Crossref], [CAS], Google Scholar
      10b
      Photochirogenesis: multidimensional control of asymmetric photochemistry
      Inoue, Yoshihisa; Wada, Takehiko; Asaoka, Sadayuki; Sato, Hirofumi; Pete, Jean-Pierre
      Chemical Communications (Cambridge) (2000), (4), 251-259CODEN: CHCOFS; ISSN:1359-7345. (Royal Society of Chemistry)
      A review with 37 refs. Photochirogenesis, or photochem. induction of mol. chirality, is an attractive alternative to thermal or enzymic asym. synthesis. Using the inherent advantage that the photochem. reaction is driven by light absorption, the effect of temp. on optical yield was investigated over a wide range. Unexpectedly, the stereochem. of photoproduct was frequently inverted at a crit. temp. (T0), above which the optical yield increased with increasing temp. The Eyring treatment of the relative rate const. for the prodn. of each enantiomer revealed that the unusual temp. dependency originates from the non-zero differential entropy of activation for the enantiodifferentiating process. In this case, the enthalpy term dominates at lower temps., while the entropy term becomes more important above T0, switching the product chirality. The abs. configuration of photoproduct obtained at temps. lower than T0 was correlated to that of the chiral sensitizer, except for those contg. very bulky chiral auxiliaries, the stereochem. outcomes are discussed on the basis of the mol. model examns. Interestingly, similar switching behavior was induced by varying the pressure from 0.1 to 400 MPa. The pressure effect was investigated at different temps. to construct three-dimensional diagrams that correlate the optical yield with temp. and pressure as mutually independent factors. The combined use of temp. and pressure provides us with a convenient, powerful tool for controlling the product chirality and optical yield in asym. photochem.
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    11. 11
      Inoue, Y.; Matsushima, E.; Wada, T. Pressure and Temperature Control of Product Chirality in Asymmetric Photochemistry. Enantiodifferentiating Photoisomerization of Cyclooctene Sensitized by Chiral Benezenepolycarboxylates. J. Am. Chem. Soc. 1998, 120, 10687– 10696,  DOI: 10.1021/ja981929a
      [ACS Full Text ACS Full Text], [CAS], Google Scholar
      11
      Pressure and temperature control of product chirality in asymmetric photochemistry - Enantiodifferentiating photoisomerization of cyclooctene sensitized by chiral benzenepolycarboxylates
      Inoue, Yoshihisa; Matsushima, Eiji; Wada, Takehiko
      Journal of the American Chemical Society (1998), 120 (41), 10687-10696CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)
      Pressure effects upon asym. photosensitization have been investigated for the first time in the enantiodifferentiating Z-E photoisomerization of cyclooctene (1), sensitized by chiral arom. esters (2-7). The product's enantiomeric excess (ee) and E/Z ratio were crit. functions of the applied pressure, exhibiting an unprecedented switching of the product chirality. Depending upon the chiral sensitizer employed, the differential activation vol. (ΔΔV⧧) varies widely from -3.7 to +5.6 cm3 mol-1, which is unexpectedly large for an enantiodifferentiation in the excited state. However, the ΔΔV⧧ values obtained do not correlate with the differential activation enthalpy (ΔΔH⧧) or entropy (ΔΔS⧧) obtained from temp.-dependence studies, indicating that pressure and temp. function as independent perturbants for the photoenantiodifferentiation process. Further investigations on the pressure dependence of ee at low temps. enable us to construct the first three-dimensional diagram that correlates the product's ee with pressure and temp. changes. The combined effects of temp. and pressure provide us with a versatile tool for the multidimensional control of asym. photochem. reactions, in which we can switch and/or enhance the product chirality at more readily accessible temps. and pressures, without using antipodal sensitizers.
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    12. 12
      (a) Weber, G.; Tanaka, F.; Okamoto, B. Y.; Drickamer, H. G. The Effect of Pressure on the Molecular Complex of Isoalloxazine and Adenine. Proc. Natl. Acad. Sci. U.S.A 1974, 71, 1264– 1266,  DOI: 10.1073/pnas.71.4.1264
      [Crossref], [PubMed], [CAS], Google Scholar
      12a
      Effect of pressure on the molecular complex of isoalloxazine and adenine
      Weber, Gregorio; Tanaka, Fumio; Okamoto, Byron Y.; Drickamer, Harry G.
      Proceedings of the National Academy of Sciences of the United States of America (1974), 71 (4), 1264-6CODEN: PNASA6; ISSN:0027-8424.
      The effect of pressure to 10 kilobars on the fluorescence characteristics of FMN [146-17-8], FAD [146-14-5], and on complexes of FMN with AMP [61-19-8], and with I- [20461-54-5] was studied. The properties measured include peak location, fluorescence yield, and lifetime. The equil. const. K and the rate const. k+* for complex formation were evaluated as a function of pressure. The pressure dependence of these coeffs. shows that the vol. of the system decreases upon complex formation and that there is an expansion upon formation of the activated complex. The implications of these results for protein denaturation are mentioned.
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      .
      (b) Torgerson, P. M.; Drickamer, H. G.; Weber, G. Inclusion Complexes of Poly-β-cyclodextrin: A Model for Pressure Effects upon Ligand-Protein Complexes. Biochemistry 1979, 18, 3079– 3083,  DOI: 10.1021/bi00581a026
      [ACS Full Text ACS Full Text], [CAS], Google Scholar
      12b
      Inclusion complexes of poly-β-cyclodextrin: a model for pressure effects upon ligand-protein complexes
      Torgerson, P. M.; Drickame, H. G.; Weber, Gregorio
      Biochemistry (1979), 18 (14), 3079-83CODEN: BICHAW; ISSN:0006-2960.
      Certain protein-ligand complexes are destabilized by application of pressures of the order of 5-10 kbar, whereas others are stabilized. This divergent behavior is attributed to differences in compressibility of the protein binding sites. Pressure-stabilized binding is thought to be characteristic of soft binding sites, sites in which rotation about backbone bonds permits redn. of the site dimensions under pressure. In contradistinction, hard binding sites do not decrease their size when pressure is applied. As a model for this latter kind, the changes in equil. with pressure were measured for complexes of poly-β-cyclodextrin with 2 fluorescent probes: 8-anilinonaphthalene-1-sulfonate and 6-propionyl-2-(dimethylamino)naphthalene. The std. vol. change upon formation of the complexes at 1 atm. is similar in both (+9.3 mL/mol), and as expected, the incompressibility of the cyclodextrin rings results in a site from which the probes are dissocd. by pressure. On the assumption of incompressibility of the binding site, the exptl. data permit the calcn. of pressure vs. vol. curves (compressibility curves) for the probes molecularly dispersed in water. These curves are in broad agreement with those of liq. aliph. and arom. hydrocarbons in the low-pressure range (1-4 kbar) but indicate a reduced compressibility at higher pressures. Considerations of relative compressibility offer a quant. alternative to the usual qual. discussion of the effects of high pressure upon protein in terms of the participation of hydrophobic and other bonds.
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      .
      (c) Williams, R. K. Pressure Enhancement of Charge-Trasfer Complexing of 1-Methyl-3-(carbomethoxy)pyridinium Cation and 8-Chlorotheophyllinate Anion in Aqueous Solution. J. Phys. Chem. 1981, 85, 1795– 1799,  DOI: 10.1021/j150613a007
      [ACS Full Text ACS Full Text], [CAS], Google Scholar
      12c
      Pressure enhancement of charge-transfer complexing of 1-methyl-3-(carbomethoxy)pyridinium cation and 8-chlorotheophyllinate anion in aqueous solution
      Williams, R. Kenneth
      Journal of Physical Chemistry (1981), 85 (13), 1795-9CODEN: JPCHAX; ISSN:0022-3654.
      Assocn. consts. were detd. for the title ions at 0.10-209.5 MPa. The apparent vol. change on assocn. is estd. to be -4.0 ± 0.5 cm3/mol, and the increment in compressibility is 0.0 Pa-1. No significant change in the increment in the extinction coeff. was obsd. The results are interpreted in terms of the vol. changes to be expected on assocn. due to an ion pairing, charge transfer, and the approach of arom. rings in water.
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      .
      (d) Letcher, T. M.; Mercer-Chalmers, J. D.; Kay, R. L. Volume changes in complex formation between crown ethers of cryptand-222 and alkali metals in various solvents. Pure Appl. Chem. 1994, 66, 419– 427,  DOI: 10.1351/pac199466030419
      [Crossref], [CAS], Google Scholar
      12d
      Volume changes in complex formation between crown ethers of cryptand-222 and alkali metals in various solvents
      Letcher, T. M.; Mercer-Chalmers, J. D.; Kay, R. L.
      Pure and Applied Chemistry (1994), 66 (3), 419-27CODEN: PACHAS; ISSN:0033-4545.
      The vol. changes ΔV∞ in crown ether or cryptand-222 + metal salt reactions are large. These reactions are interesting in that the metal ion is apparently enveloped by the larger org. mol. and as a result these measurements can shed light on the processes involved. ΔV∞ not only reflects the proposed simple mechanism but also is a measure of the electrostriction effect of the metal ion on the solvent.
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      .
      (e) Isaacs, N. S.; Nichols, P. J.; Raston, C. L.; Sandova, C. A.; Young, D. J. Solution volume studies of a deep cavity inclusion complex of C60: [p-benzylcalix[5]arene ⊂ C60]. Chem. Commun. 1997, 1839– 1840,  DOI: 10.1039/a702200j
      [Crossref], [CAS], Google Scholar
      12e
      Solution volume studies of a deep cavity inclusion complex of C60: [p-benzylcalix[5]arene ⊂ C60]
      Isaacs, Neil S.; Nichols, Peter J.; Raston, Colin L.; Sandova, Christian A.; Young, David J.
      Chemical Communications (Cambridge) (1997), (19), 1839-1840CODEN: CHCOFS; ISSN:1359-7345. (Royal Society of Chemistry)
      Mol. complexation of C60 with p-benzylcalix[5]arene in toluene is assocd. with a partial molar volume change of +195 cm3 mol-1 which is consistent with the displacement of two toluene mols. from the cavity of the calixarene.
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      .
      (f) Abou-Hamdan, A.; Bugnon, P.; Saudan, C.; Lye, P. G.; Merbach, A. E. High-Pressure Studies as a Novel Approach in Determining Inclusion Mechanisms: Thermodynamics and Kinetics of the Host-Guest Interactions for α-Cyclodextrin Complexes. J. Am. Chem. Soc. 2000, 122, 592– 602,  DOI: 10.1021/ja993139m
      [ACS Full Text ACS Full Text], [CAS], Google Scholar
      12f
      High-Pressure Studies as a Novel Approach in Determining Inclusion Mechanisms: Thermodynamics and Kinetics of the Host-Guest Interactions for α-Cyclodextrin Complexes
      Abou-Hamdan, Amira; Bugnon, Pascal; Saudan, Christophe; Lye, Peter G.; Merbach, Andre E.
      Journal of the American Chemical Society (2000), 122 (4), 592-602CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)
      The first vol. profiles for complex formation of α-cyclodextrins (α-CD) with di-Ph azo dyes (S) are presented as a new approach in understanding inclusion phenomena. The following dyes were selected: sodium 4-(4-diethylaminophenylazo)benzenesulfonate, sodium 4-(3-carboxy-4-hydroxy-5-methylphenylazo)benzenesulfonate, sodium 4-(4-hydroxy-3,5-dimethylphenylazo)benzenesulfonate, and sodium 2-hydroxy-3-methyl-5-(4-sulfamoylphenylazo)benzoate. The behavior of the dyes alone was first studied in aq. solns. to rule out any competition reaction. Under the exptl. conditions used for the stopped-flow kinetic studies, it has been proved that only monomeric species are present (no aggregation of the dye is formed by π-π stacking interactions). NMR expts. and kinetic evidences have shown that only directional binding of the dye via the sulfonate/sulfonamide group through the wide rim of the α-cyclodextrin was possible. The 1:1 complex was the only stoichiometric species formed. The inclusion reactions for the four selected dyes were characterized by a two-step kinetics described by a first fast step that yields the intermediate, S·α-CD*, followed by a slower rearrangement to form the final complex, S·α-CD. 2D NMR expts. served for a mol. dynamics calcn. leading to a structural representation of the intermediate and final complexes. An interpretation of the vol. profiles obtained from high-pressure stopped-flow kinetic expts. have not only confirmed the so far proposed mechanisms based on "classical" kinetic investigations but offered a new focus on the inclusion process. The inclusion mechanism can be summarized now as follows: the complexation begins with an encounter of the dye and α-cyclodextrin mainly due to hydrophobic interactions followed by a partial desolvation of the entering head of the dye. The latter interacts with the two "activated" inner water mols. of the free host and their complete release is delayed by the primary hydroxy group barrier of the α-CD. At this first transition state, a squeezed arrangement develops inside the cavity inducing a neg. activation vol. (ΔV1,f⧧ ≈ -8 to -24 cm3 mol-1). The subsequent intermediate is characterized by a total release of the two inner water mols. and interactions of the dye head with the primary hydroxy groups of the host in a trapped-like structure (ΔV1° ≈ -11 to -4 cm3 mol-1). The latter interactions and concurrent tail interactions with the secondary hydroxy groups of the host lead at different extents to a strained conformation of the host in the second transition state (ΔV2,f⧧ ≈ -2 to -16 cm3 mol-1). In the final complex, the head of the dye is totally rehydrated as it protrudes from the primary end of the host cavity which can now adopt a released conformation (ΔV2° ≈ +3 to +6 cm3 mol-1 vs +17 cm3 mol-1 for 1).
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      .
      (g) Saudan, C.; Dunand, F. A.; Abou-Hamdan, A.; Bugnon, P.; Lye, P. G.; Lincoln, S. F.; Merbach, A. E. A Model for Sequential Threading of α-Cyclodextrin onto a Guest: A Complete Thermodynamic and Kinetic Study in Water. J. Am. Chem. Soc. 2001, 123, 10290– 10298,  DOI: 10.1021/ja010946o
      [ACS Full Text ACS Full Text], [CAS], Google Scholar
      12g
      A Model for Sequential Threading of α-Cyclodextrin onto a Guest: A Complete Thermodynamic and Kinetic Study in Water
      Saudan, Christophe; Dunand, Frank A.; Abou-Hamdan, Amira; Bugnon, Pascal; Lye, Peter G.; Lincoln, Stephen F.; Merbach, Andre E.
      Journal of the American Chemical Society (2001), 123 (42), 10290-10298CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)
      The first variable-temp. and variable-pressure stopped-flow spectrophotometric study of the sequential threading of α-cyclodextrin (α-CD) onto the guest dye Mordant Orange 10, S, is reported. Complementary 1H one-dimensional (1D) variable-temp. kinetic studies and two-dimensional (2D) rotating-frame nOe spectroscopy (ROESY) and EXSY NMR studies are also reported. In aq. soln. at 298.2 K, the first α-CD threads onto S to form a 1:1 complex S·α-CD* with a forward rate const. k1,f = 15 200 ± 200 M-1 s-1 and dethreads with a reverse rate const. k1,r = 4.4 ± 0.3 s-1. Subsequently, S·α-CD* isomerizes to S·α-CD (k3,f = 0.158 ± 0.006 s-1, k3,f = 0.148 ± 0.006 s-1). This process can be viewed as a thermodynamically controlled mol. shuttle. A second α-CD threads onto S·α-CD* to form a 1:2 complex, S·(α-CD)2*, with k2,f = 98 ± 2 M-1 s-1 and k2,r = 0.032 ± 0.002 s-1. A second α-CD also threads onto S·α-CD to form another 1:2 complex, S·(α-CD)2, characterized by k4,f = 9640 ± 1800 M-1 s-1 and k4,r = 61 ± 6 s-1. Direct interconvertion between S·(α-CD)2* and S·(α-CD)2 was not detected; instead, they interconvert by dethreading the second α-CD and through the isomerization equil. between S·α-CD* and S·α-CD. The reaction vols., ΔV0, were found to be neg. for the first three equil. and pos. for the fourth equil. For the first three forward and reverse reactions, the vols. of activation are substantially more neg., indicating a compression of the transition state in comparison with the ground states. These data were used in conjunction with ΔH⧧, ΔH°, ΔS⧧, and ΔS° data to deduce the dominant mechanistic threading processes, which appear to be largely controlled by changes in hydration and van der Waals interactions, and possibly by conformational changes in both S and α-CD. The structure of the four complexes was deduced from 1H 2D ROESY NMR studies.
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      .
      (h) Ruloff, R.; Seelbach, U. P.; Merbach, A. E.; Klärner, F.-G. Molecular tweezers as synthetic receptors: the effect of presssure and temperature on the formation of host-guest complexes. J. Phys. Org. Chem. 2002, 15, 189– 196,  DOI: 10.1002/poc.477
      [Crossref], [CAS], Google Scholar
      12h
      Molecular tweezers as synthetic receptors: the effect of pressure and temperature on the formation of host-guest complexes
      Ruloff, Robert; Seelbach, Uta P.; Merbach, Andre E.; Klarner, Frank-Gerrit
      Journal of Physical Organic Chemistry (2002), 15 (4), 189-196CODEN: JPOCEE; ISSN:0894-3230. (John Wiley & Sons Ltd.)
      For the formation of the supramol. complexes between the mol. tweezers and arom. guests the vols. of reaction ΔV were detd. from the pressure dependence of the assocn. consts. K by the use of high-pressure 1H NMR spectroscopy and the enthalpy ΔH and entropy ΔS of reaction from the temp. dependence of K. The small pressure dependence of K and, hence, the small variation of the reaction vols. around the zero value (ΔV ≈ 0 cm3 mol-1) clearly indicate that the contraction in vol. resulting from the host-guest assocn. is compensated for by the expansion in vol. resulting from the desolvation of the free host and guest which has to proceed during the complexation. The assocn. and desolvation are expected to have similar effects on ΔS compensating each other. The significant deviations of ΔS from the zero value are, however, good evidence that the size of ΔS not only depends on the processes mentioned above but moreover is influenced by other factors such as the conformational mobility of the guest mol. inside the receptor cavity.
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      .
      (i) Yang, C.; Nakamura, A.; Fukuhara, G.; Origane, Y.; Mori, T.; Wada, T.; Inoue, Y. Pressure and Temperature-Controlled Enantiodifferentiating [4+4] Photocyclodimerization of 2-Anthracenecarboxylate Mediated by Secondary Face- and Skeleton-Modified γ-Cyclodextrins. J. Org. Chem. 2006, 71, 3126– 3136,  DOI: 10.1021/jo0601718
      [ACS Full Text ACS Full Text], [CAS], Google Scholar
      12i
      Pressure and Temperature-Controlled Enantio-Differentiating [4+4]-Photo-Cyclodimerization of 2-Anthracene-carboxylate Mediated by Secondary Face- and Skeleton-Modified γ-Cyclodextrins
      Yang, Cheng; Nakamura, Asao; Fukuhara, Gaku; Origane, Yumi; Mori, Tadashi; Wada, Takehiko; Inoue, Yoshihisa
      Journal of Organic Chemistry (2006), 71 (8), 3126-3136CODEN: JOCEAH; ISSN:0022-3263. (American Chemical Society)
      A series of secondary-face-substituted and skeleton-modified γ-cyclodextrins (γ-CDs) were prepd. as chiral hosts for enantio-differentiating [4+4]-photo-cyclodimerization reactions of 2-anthracene-carboxylic acid (AC). These γ-CD derivs. form stable ternary complexes with ACs, with altroside-bearing γ-CDs undergoing induced-fit conformational changes upon complexation, and the photo-cyclodimerization of AC was, thus, dramatically accelerated. The enantiomeric excess (ee) of anti-head-to-head cyclodimer was greatly enhanced in general with altroside-bearing γ-CDs. The influence of temp. and high pressure on the supra-mol. photo-chirogenic reaction has been investigated in depth. An enantiomeric excess as high as 71% was obtained for cyclodimer in the photo-cyclodimerization of AC mediated by 3A-amino-3A-deoxy-altro-γ-CD at 210 MPa and -21.5 °C.
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      .
      (j) Yang, C.; Mori, T.; Origane, Y.; Ko, Y. H.; Selvapalam, N.; Kim, K.; Inoue, Y. Highly Stereoselective Photocyclodimerization of α-Cyclodextrin-Appended Anthracene Mediated by γ-Cyclodextrin and Cucurbit[8]uril: A Dramatic Steric Effect Operating Outside the Binding Site. J. Am. Chem. Soc. 2008, 130, 8574– 8575,  DOI: 10.1021/ja8032923
      [ACS Full Text ACS Full Text], [CAS], Google Scholar
      12j
      Highly Stereoselective Photocyclodimerization of α-Cyclodextrin-Appended Anthracene Mediated by γ-Cyclodextrin and Cucurbit[8]uril: A Dramatic Steric Effect Operating Outside the Binding Site
      Yang, Cheng; Mori, Tadashi; Origane, Yumi; Ko, Young Ho; Selvapalam, Narayanan; Kim, Kimoon; Inoue, Yoshihisa
      Journal of the American Chemical Society (2008), 130 (27), 8574-8575CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)
      Photocyclodimerization of α-cyclodextrin (CD)-appended anthracene was studied in the presence of γ-CD and cucurbit[8]uril (CB[8]) hosts to manipulate the stereo-differentiating photoreaction occurring inside the cavity by the bulky attachment located outside. The γ-CD-mediated photodimerization afforded the head-to-tail photodimers in 98% combined yield, in particular, the syn-head-to-tail photodimer of 91% ee in 68% yield, which are much greater than 32% ee and 44% yield obtained with unmodified anthracene carboxylate. The use of CB[8] also led to a striking inversion of the head-to-tail/head-to-head selectivity, affording exclusively the head-to-head photodimers in 99% combined yield.
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      (k) Kosaka, T.; Iwai, S.; Fukuhara, G.; Imai, Y.; Mori, T. Hydrostatic Pressure on Toroidal Interactinon and Propeller Chirality of Hexaarylbenzens: Explicit Solvent Effects on Differential Volumes in Methylcyclohexane and Hexane. Chem. Eur. J. 2019, 25, 2011– 2018,  DOI: 10.1002/chem.201804688
      [Crossref], [PubMed], [CAS], Google Scholar
      12k
      Hydrostatic Pressure on Toroidal Interaction and Propeller Chirality of Hexaarylbenzenes: Explicit Solvent Effects on Differential Volumes in Methylcyclohexane and Hexane
      Kosaka, Tomoyo; Iwai, Satono; Fukuhara, Gaku; Imai, Yoshitane; Mori, Tadashi
      Chemistry - A European Journal (2019), 25 (8), 2011-2018CODEN: CEUJED; ISSN:0947-6539. (Wiley-VCH Verlag GmbH & Co. KGaA)
      A unique and effective interaction between the peripheral arom. blades makes hexaarylbenzenes (HABs) attractive in fundamental research as well as for various applications such as mol. wires, sensors, and supramol. assemblies. The chiroptical responses of HABs are susceptible to environmental factors such as solvent and temp. owing to the dynamic conformational transitions between the conformers. In this study, pressure dependence on the propeller chiral HABs in two different solvents was studied in detail. The effective differential vols. for two different equil. were detd. by quant. analyses of CD spectra, affording very large differential vols. from the propeller to toroidal conformer (ΔVT-C) of +43 and +42 cm3 mol-1, for H2 and H6, resp., in methylcyclohexane. The value of H6 was further enhanced to +72 cm3 mol-1 in hexane, the largest value for the typical unimol. conformational change. Such a response of propeller chirality in HABs is expedient in designing more advanced piezo-sensitive materials.
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      (l) Yonezawa, S.; Sethy, R.; Fukuhara, G.; Kawai, T.; Nakashima, T. Pressure-dependent guest binding and release on a supramolecular polymer. Chem. Commun. 2019, 55, 5793– 5796,  DOI: 10.1039/C9CC02696G
      [Crossref], [PubMed], [CAS], Google Scholar
      12l
      Pressure-dependent guest binding and release on a supramolecular polymer
      Yonezawa, Shumpei; Sethy, Ramarani; Fukuhara, Gaku; Kawai, Tsuyoshi; Nakashima, Takuya
      Chemical Communications (Cambridge, United Kingdom) (2019), 55 (41), 5793-5796CODEN: CHCOFS; ISSN:1359-7345. (Royal Society of Chemistry)
      Chiral guest binding on a self-assembly of a bichromophoric naphthalenediimide (NDI) deriv. is modulated in response to pressure. The intermol. packing in the supramol. polymer is strengthened at high pressure, compressing the binding pockets and discharging the guest mols.
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    13. 13
      (a) Johnson, P. C.; Offen, H. W. Effect of Pressure on Pyrene Excimer Fluorescence in Toluene. J. Chem. Phys. 1972, 56, 1638– 1642,  DOI: 10.1063/1.1677418
      [Crossref], [CAS], Google Scholar
      13a
      Effect of pressure on pyrene excimer fluorescence in toluene
      Johnson, P. C.; Offen, H. W.
      Journal of Chemical Physics (1972), 56 (4), 1638-42CODEN: JCPSA6; ISSN:0021-9606.
      The pressure dependence of pyrene fluorescence in PhMe was measured to 10 kbar. The monomer and excimer fluorescence decay kinetics are analyzed to give the rate parameters for excimer formation, dissocn., and unimol. decay as a function of pressure at 296, 320, and 340°K. Activation parameters are evaluated both as a function of temp. and as a function of pressure. The pressure dependence of the assocn. is in one-to-one correspondence with the solvent viscosity. The rate of dissocn. is strongly inhibited by high pressures. The vol. change on excimer formation is -11 cm3/mole at 296°K. The enthalpy and free energy of excimer formation are -9.7 and -4.2 kcal/mole at 1 atm, and -3.6 and -6.7 kcal/mole at 10 kbar, resp.
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      .
      (b) Rollinson, A. M.; Drickamer, H. G. High Pressure Study of Luminescence from Intramolecular CT Compounds. J. Chem. Phys. 1980, 73, 5981– 5996,  DOI: 10.1063/1.440132
      [Crossref], [CAS], Google Scholar
      13b
      High pressure study of luminescence from intramolecular CT compounds
      Rollinson, A. M.; Drickamer, H. G.
      Journal of Chemical Physics (1980), 73 (12), 5981-96CODEN: JCPSA6; ISSN:0021-9606.
      The effects of high pressure on the luminescence properties of 4 org. intramol. charge transfer compds. were investigated. The compds. were studied in a wide range of liq. and polymeric environments, and for 1 of the compds., the effect of chem. substitution was also examd. In general, an increase of pressure affects the luminescence in a way which is similar to an increase of solvent polarity. A single configuration coordinate model was used to interpret the luminescence in terms of excited state interactions. Three of the compds. exhibited only fluorescence; p-(9-anthryl)-dimethylaniline (ADMA), 6-propionyl-2-dimethylaminonaphthalene (PRODAN), and 1-anilino-8-naphthalenesulfonate (ANS). Fluorescence from the 1st 2 compds. in nonpolar media is attributed to an excited state relatively unaffected by the charge transfer process. In polar media, fluorescence is believed to originate from another excited state that possesses considerably charge transfer character, and whose energy is strongly influenced by solvent polarity. The 4th compd., nitroaniline, was studied in its 3 isomeric forms, with and without N-methylation. In addn. to affecting the phosphorescence and fluorescence of p-nitroaniline, pressure studies indicate that nπ* singlet and triplet states figure prominently in the radiative and nonradiative processes of o-nitroaniline and m-nitroaniline as well.
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      .
      (c) Hara, K.; Arase, T.; Osugi, J. Effect of High Pressure on Intramolecular Electron-Transfer Luminescence of 9,9′-Bianthryl in Different Solvents. J. Am. Chem. Soc. 1984, 106, 1968– 1972,  DOI: 10.1021/ja00319a012
      [ACS Full Text ACS Full Text], [CAS], Google Scholar
      13c
      Effect of high pressure on intramolecular electron-transfer luminescence of 9,9'-bianthryl in different solvents
      Hara, Kimihiko; Arase, Takuya; Osugi, Jiro
      Journal of the American Chemical Society (1984), 106 (7), 1968-72CODEN: JACSAT; ISSN:0002-7863.
      The effects of high pressure on the fluorescence from the intramol. electron-transfer state of 9,9'-bianthryl were investigated in different solvents. In low-viscosity solvents an increase of pressure affects the emission similarly to an increase of solvent polarity. In moderately viscous solvents the formation of the electron-transfer state is quenched as pressure is increased. In highly viscous solvents, as in glycerol, the emission is only from the locally excited state at atm. pressure, and no change except for peak shift is obsd. with pressure increase. Freezing of solvents at high pressure strictly quenches the formation of the electron-transfer state.
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      .
      (d) Hara, K.; Obara, K. Effect of Pressure on the Formation of the Intramolecular Excited Complex State in 4-(9-Anthrylmethyl)-N,N-dimethylaniline. Chem. Phys. Lett. 1985, 117, 96– 98,  DOI: 10.1016/0009-2614(85)80412-7
      [Crossref], [CAS], Google Scholar
      13d
      Effect of pressure on the formation of the intramolecular excited complex state in 4-(9-anthrylmethyl)-N,N-dimethylaniline
      Hara, Kimihiko; Obara, Kazuyuki
      Chemical Physics Letters (1985), 117 (1), 96-8CODEN: CHPLBC; ISSN:0009-2614.
      The formation of an intramol. excited complex state in 4-(9-anthrylmethyl)-N,N-dimethylaniline was investigated at high pressures. A change in the kinetics from thermodn. control to kinetic control was obsd. in Et ether solvent. In toluene, the process is kinetically controlled over the whole pressure range. Appearance of this process depends upon the solvent viscosity, suggesting a conformational change in the course of the formation of the excited complex state.
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      .
      (e) Hara, K.; Yano, H. High-Pressure Study on Intramolecular Excimer Formation of 1,3-Di-1-pyrenylpropane in Various Solvents. J. Am. Chem. Soc. 1988, 110, 1911– 1915,  DOI: 10.1021/ja00214a040
      [ACS Full Text ACS Full Text], [CAS], Google Scholar
      13e
      High-pressure study on intramolecular excimer formation of 1,3-di-1-pyrenylpropane in various solvents
      Hara, Kimihiko; Yano, Hiroyuki
      Journal of the American Chemical Society (1988), 110 (6), 1911-15CODEN: JACSAT; ISSN:0002-7863.
      Viscosity effects on intramol. excimer (IE) formation in the title compd. were examd. at high pressures in various solvents. IE formation depends strongly and exclusively on solvent viscosity, but is insensitive to solvent polarity. The rates of IE formation estd. from fluorescence quantum yields are represented as a unique function of solvent viscosity. A hindered-rotation model based on Kramers' theory was applied successfully. More general results without specific interaction of solvent were obtained. The intrinsic activation energy (15-18 kJ/mol), the intrinsic activation vol. (-2.5 cm3/mol), and the frequency for the top of the barrier of IE formation were detd.
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      .
      (f) Rettig, W.; Gilabert, E.; Rulliére, C. Pressure Dependence of Bicimer Formation in 4-Dimethylamino-4′-cyanostilbene and Model Compounds. Chem. Phys. Lett. 1994, 229, 127– 133,  DOI: 10.1016/0009-2614(94)01005-6
      [Crossref], [CAS], Google Scholar
      13f
      Pressure dependence of bicimer formation in 4-dimethylamino-4'-cyanostilbene and model compounds
      Rettig, W.; Gilabert, E.; Rulliere, C.
      Chemical Physics Letters (1994), 229 (1,2), 127-33CODEN: CHPLBC; ISSN:0009-2614. (Elsevier)
      4-Dimethylamino-4'-cyanostilbene and selectively bridged model compds. are investigated using ps-time-resolved absorption and fluorescence measurements. The formation kinetics of a bicimer species are compared in homologous alc. solvents at ambient pressure and as a function of high pressure, and the viscosity dependences are discussed.
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      .
      (g) Hara, K.; Kometani, N.; Kajimoto, O. High-Pressure Studies on the Excited-State Intramolecular Charge Transfer of 4-(N,N-Dimethylamino)triphenylphosphine in Alcohols. J. Phys. Chem. 1996, 100, 1488– 1493,  DOI: 10.1021/jp952270n
      [ACS Full Text ACS Full Text], [CAS], Google Scholar
      13g
      High-Pressure Studies on the Excited-State Intramolecular Charge Transfer of 4-(N,N-Dimethylamino)triphenylphosphine in Alcohols
      Hara, Kimihiko; Kometani, Noritsugu; Kajimoto, Okitsugu
      Journal of Physical Chemistry (1996), 100 (5), 1488-93CODEN: JPCHAX; ISSN:0022-3654. (American Chemical Society)
      The influence of solvent viscosity on the intramol. charge-transfer (CT)-state formation in the excited S1 state for 4-(N,N-dimethylamino) triphenylphosphine (DMATP) in alc. solvents has been investigated by measuring the steady-state and time-resolved fluorescence spectra at high pressures. The kinetic mechanism of the intramol. CT reaction has been examd. as a function of solvent shear viscosity. In the lower viscosity region the reaction is controlled by the solvent relaxation. With increasing pressure, the reaction path shifts toward the "high-viscosity regime" in which the mol. moves along the non-relaxed path on the free energy surface. The viscosity dependence of α equiv. 0.33, where α is the power law parameter, can be interpreted as the extreme value in which the reaction is controlled by the dynamic solvent effect due to intrinsic collisional interaction of barrier crossing. The coupling between the intramol. CT-state formation dynamics of DMATP and the solvent relaxation dynamics is discussed.
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      .
      (h) Ruan, K.; Tian, S.; Lange, R.; Balny, C. Pressure Effects on Tryptophan and Its Derivatives. Biochem. Biophys. Res. Commun. 2000, 269, 681– 686,  DOI: 10.1006/bbrc.2000.2345
      [Crossref], [PubMed], [CAS], Google Scholar
      13h
      Pressure Effects on Tryptophan and Its Derivatives
      Ruan, Kangcheng; Tian, Shaoming; Lange, Reinhard; Balny, Claude
      Biochemical and Biophysical Research Communications (2000), 269 (3), 681-686CODEN: BBRCA9; ISSN:0006-291X. (Academic Press)
      The high pressure effects on fluorescence of free tryptophan (Trp) and its derivs., N-acetyl-tryptophan (AT), N-acetyl-tryptophanamide (NATA), tryptophanamide (TA), and tryptophan, contg. 6-polypeptides in aq. soln., were investigated in a pressure range from 0.1 to 650 MPa. It was found by analyzing the center of spectral mass in the wavelength range from 300 to 450 nm that high pressure shifted the fluorescence spectra of all these species to red direction: 421 cm-1 for Trp, 305 cm-1 for AT, 310 cm-1 for NATA, 265 cm-1 for TA, and 220 cm-1 for single tryptophan contg. 6-polypeptides. All the fluorescence efficiencies (i.e., quantum yield) of the compds. were reduced with pressure except free tryptophan where its fluorescence efficiency was enhanced with pressure. Glycerol, ethanol, and pH obviously influenced the pressure effects on their fluorescence characteristics. Since the tryptophan fluorescence is usually used as a probe for protein structural investigation, these findings suggested that the intrinsic pressure effect on tryptophan (or its derivs.) must be taken in consideration to explain the phenomenon obsd. in high pressure study on biomols. when using the usual fluorospectroscopic approaches. In the present investigation, the mechanisms involved for pressure effects on tryptophan and its derivs. were explored and discussed. (c) 2000 Academic Press.
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      .
      (i) Alamiry, M. A. H.; Benniston, A. C.; Copley, G.; Elliott, K. J.; Harriman, A.; Stewart, B.; Zhi, Y.-G. A Molecular Rotor Based on an Unhindered Boron Dipyrromethene (Bodipy) Dye. Chem. Mater. 2008, 20, 4024– 4032,  DOI: 10.1021/cm800702c
      [ACS Full Text ACS Full Text], [CAS], Google Scholar
      13i
      A Molecular Rotor Based on an Unhindered Boron Dipyrromethene (Bodipy) Dye
      Alamiry, Mohammed A. H.; Benniston, Andrew C.; Copley, Graeme; Elliott, Kristopher J.; Harriman, Anthony; Stewart, Beverly; Zhi, Yong-Gang
      Chemistry of Materials (2008), 20 (12), 4024-4032CODEN: CMATEX; ISSN:0897-4756. (American Chemical Society)
      This work describes a fluorescent probe for following changes in the viscosity of the surrounding medium. The optical properties, fluorescence characteristics, and sensitivity to frictional forces with the surrounding medium are superior to the most commonly used mol. probe, namely dicyanovinyl julolidine. The photophys. properties of the target mol. have been recorded in a range of solvents under ambient conditions, over a wide temp. range, and as a function of applied pressure. The mechanism by which the probe responds to changes in local viscosity involves gyration of the meso-phenylene ring and accompanying distortion of the dipyrrin framework, as indicated by mol. dynamics simulations. Indeed, temp.-dependence measurements have established that the activation energy is small when the solvent viscosity is relatively low, but there is a turnover to strong activation control at very high viscosity. A small but definite solvent dependence appears when the viscosity is varied by the application of high pressures and this can be traced to differences in the elasticity of the surroundings. Unusually for such fluorescent rotors, there is no indication that the excited state involves charge-transfer interactions. The rotor also responds to changes in the polarizability of the solvent, as induced by changes in applied pressure, and to the extent of polymn. of a monomer. The various exptl. observations made at low viscosity are consistent with diffusive motion of the wave packet along the excited-state potential curve until finding a sink that strongly coupled to the highly distorted ground state.
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      .
      (j) Alamiry, M. A. H.; Bahaidarah, E.; Harriman, A.; Bura, T.; Ziessel, R. Fluorescent molecular rotors under pressure: synergistic effects of an inert polymer. RSC Adv. 2012, 2, 9851– 9859,  DOI: 10.1039/c2ra20786a
      [Crossref], [CAS], Google Scholar
      13j
      Fluorescent molecular rotors under pressure: synergistic effects of an inert polymer
      Alamiry, Mohammed A. H.; Bahaidarah, Effat; Harriman, Anthony; Bura, Thomas; Ziessel, Raymond
      RSC Advances (2012), 2 (26), 9851-9859CODEN: RSCACL; ISSN:2046-2069. (Royal Society of Chemistry)
      Sterically unhindered boron dipyrromethene dyes bearing aryl hydrocarbons at the meso position can function as fluorescent probes for monitoring changes in rheol. of the surrounding environment. The key aspect of such behavior relates to the ease of rotation of the aryl ring, which is set in part by frictional forces with nearby solvent mols. For the target dye under consideration here, gyration of the meso-phenylene ring shows a pronounced temp. dependence but only a modest sensitivity towards applied pressure. Changing the specific viscosity of the solvent by adding a linear polymer has but a small effect on the fluorescence yield of the dye under ambient conditions and thereby indicates that there is little contact between dye and polymer. Under pressure in the presence of polymer, the fluorescence yield increases dramatically and allows design of an effective fluorescence-based pressure sensor. The simplest explanation of this phenomenon has the polymer wrapping around the dye under pressure and curtailing the rotary action. In addn., it has to be considered that the inert polymer renders the chloroform solvent more susceptible to a pressure-induced increase in d. by minimizing electrostatic repulsion between chlorine lone pairs. In this respect, the polymer acts as a lubricant for compression of chloroform under pressure.
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      .
      (k) Hablot, D.; Ziessel, R.; Alamiry, M. A. H.; Bahraidah, E.; Harriman, A. Nanomechanical properties of molecular-scale bridges as visualised by intramolecular electronic energy transfer. Chem. Sci. 2013, 4, 444– 453,  DOI: 10.1039/C2SC21505E
      [Crossref], [CAS], Google Scholar
      13k
      Nanomechanical properties of molecular-scale bridges as visualized by intramolecular electronic energy transfer
      Hablot, Delphine; Ziessel, Raymond; Alamiry, Mohammed A. H.; Bahraidah, Effat; Harriman, Anthony
      Chemical Science (2013), 4 (1), 444-453CODEN: CSHCCN; ISSN:2041-6520. (Royal Society of Chemistry)
      A series of mol. dyads has been synthesized and fully characterized. These linear, donor-spacer-acceptor compds. comprise terminal dyes selected to exhibit intramol. electronic energy transfer (EET) along the mol. axis. The spacer is built by accretion of ethynylene-carborane units that give center-to-center sepn. distances of 38, 57, 76, 96, and 115 Å resp. along the series. The probability of one-way EET between terminals depends on the length of the spacer but also on temp. and applied pressure. Throughout the series, the derived EET parameters are well explained in terms of through-space interactions but the probability of EET is higher than predicted for the fully extended conformation except in a glassy matrix at low temp. The implication is that these spacers contract under ambient conditions, with the extent of longitudinal contraction increasing under pressure but decreasing as the temp. is lowered. Longer bridges are more susceptible to such distortion, which is considered to resemble a concertina effect caused by out-of-plane bending of individual subunits. The dynamics of EET can be used to est. the strain energy assocd. with mol. contraction, the amt. of work done in effecting the structural change and the Young's modulus for the bridge.
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      .
      (l) Suhina, T.; Weber, B.; Carpentier, C. E.; Lorincz, K.; Schall, P.; Bonn, D.; Brouwer, A. M. Fluorescence Microscopy Visualization of Contacts Between Objects. Angew. Chem., Int. Ed. 2015, 54, 3688– 3691,  DOI: 10.1002/anie.201410240
      [Crossref], [CAS], Google Scholar
      13l
      Fluorescence Microscopy Visualization of Contacts Between Objects
      Suhina, Tomislav; Weber, Bart; Carpentier, Chantal E.; Lorincz, Kinga; Schall, Peter; Bonn, Daniel; Brouwer, Albert M.
      Angewandte Chemie, International Edition (2015), 54 (12), 3688-3691CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)
      The area of contact between two objects was detected by using the strong enhancement of the fluorescence of rigidochromic probe mols. attached to one of the surfaces. Confinement of the mols. suppresses nonradiative decay and turns on the fluorescence. The approach is demonstrated by imaging of the contact area of a plastic sphere in contact with a flat glass surface. Our results agree excellently with the prediction of Hertz's classical theory based on elastic deformation.
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      .
      (m) Sagara, Y.; Tamaoki, N.; Fukuhara, G. Cyclophane-Based Fluorescence Tuning Induced by Hydrostatic Pressure Changes. ChemPhotoChem 2018, 2, 959– 963,  DOI: 10.1002/cptc.201800163
      [Crossref], [CAS], Google Scholar
      13m
      Cyclophane-Based Fluorescence Tuning Induced by Hydrostatic Pressure Changes
      Sagara, Yoshimitsu; Tamaoki, Nobuyuki; Fukuhara, Gaku
      ChemPhotoChem (2018), 2 (11), 959-963CODEN: CHEMYH ISSN:. (Wiley-VCH Verlag GmbH & Co. KGaA)
      In contrast to a std. steady fluorescence intensity increase of a chloroform soln. of a linear chromophore unit under high pressure, a fluorescent cyclophane soln. shows significant fluorescence quenching under elevated pressure. A pressure-induced enhancement of the formation of an intramol. π-stacked conformation is proposed to be responsible.
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      .
      (n) Takeda, Y.; Mizuno, H.; Okada, Y.; Okazaki, M.; Minakata, S.; Penfold, T.; Fukuhara, G. Hydrostatic Pressure-Controlled Ratiometric Luminescence Responses of a Dibenzo[a,j]phenazine-Cored Mechanoluminophore. ChemPhotoChem 2019, 3, 1203– 1211,  DOI: 10.1002/cptc.201900190
      [Crossref], [CAS], Google Scholar
      13n
      Hydrostatic Pressure-Controlled Ratiometric Luminescence Responses of a Dibenzo[a,j]phenazine-Cored Mechanoluminophore
      Takeda, Youhei; Mizuno, Hiroaki; Okada, Yusuke; Okazaki, Masato; Minakata, Satoshi; Penfold, Thomas; Fukuhara, Gaku
      ChemPhotoChem (2019), 3 (12), 1203-1211CODEN: CHEMYH ISSN:. (Wiley-VCH Verlag GmbH & Co. KGaA)
      Understanding changes in excited state properties under the influence of an external stimulus, such as pressure or temp., is important in the context of optimizing mol. components for a no. of applications including sensors and imaging reagents. Herein, we use UV/Vis absorption, fluorescence and excitation spectroscopies and fluorescence lifetime measurements supported by calcns. to probe the effect of hydrostatic pressure on the excited state characteristics of a conformationally-divergent mechanochromic compd. PTZ-DBPHZ (contg. two phenothiazine moieties attached to a dibenzo[a,j]phenazine core) in toluene and methylcyclohexane. We demonstrate that hydrostatic pressure can be used to manipulate the equil. between excited state conformers. This work provides new perspectives for mechanoresponsive materials and as an attractive alternative to conventional ratiometric sensors.
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    14. 14
      Reichardt, C.; Welton, T. Solvents and Solvent Effects in Organic Chemistry; Wiley-VCH: Weinheim, 2011.
      Google Scholar
      There is no corresponding record for this reference.
    15. 15
      Reichardt, C. Solvatochromic Dyes as Solvent Polarity Indicators. Chem. Rev. 1994, 94, 2319– 2358,  DOI: 10.1021/cr00032a005
      [ACS Full Text ACS Full Text], [CAS], Google Scholar
      15
      Solvatochromic Dyes as Solvent Polarity Indicators
      Reichardt, Christian
      Chemical Reviews (Washington, DC, United States) (1994), 94 (8), 2319-58CODEN: CHREAY; ISSN:0009-2665.
      This review with 345 refs. compiles pos. and neg. solvatochromic compds. which have been used to establish empirical scales of solvent polarity by means of UV/visible/near-IR spectroscopic measurements in soln. with particular emphasis on the ET(30) scale derived from neg. solvatochromic pyridinium N-phenolate betaine dyes. A discussion is presented on the concept of solvent polarity and how empirical parameters of solvent polarity can be derived and understood in the framework of linear free-energy relationships.
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    16. 16
      Takagi, T.; Teranishi, H. Refractive Index of Liquids under High Pressure. J. Chem. Eng. Data 1982, 27, 16– 18,  DOI: 10.1021/je00027a003
      [ACS Full Text ACS Full Text], [CAS], Google Scholar
      16
      Refractive index of liquids under high pressure
      Takagi, Toshiharu; Teranishi, Hiroshi
      Journal of Chemical and Engineering Data (1982), 27 (1), 16-18CODEN: JCEAAX; ISSN:0021-9568.
      In order to measure the variation of the n of liqs. with pressure up to 50 MPa, a Michelson-type interferometer for 632.8-nm light is constructed. The pressure variations of the refractive indexes for mesitylene, benzene, and CCl4 which were measured and reported in the literature confirm the reliability of the interferometer. Measurements are performed on benzene, PhMe, PhCl, and PhNO2 at several temps. and pressures up to 50 MPa, with an estd. accuracy of better than ±0.00008.
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    17. 17
      Bovey, F. A.; Yanari, S. S. Effect of Solvent Polarizality on the Ultra-Violet Spectral Shifts of Aromatic Compounds. Nature 1960, 186, 1042– 1044,  DOI: 10.1038/1861042a0
      [Crossref], [CAS], Google Scholar
      17
      Effect of solvent polarizability on the ultraviolet spectral shifts of aromatic compounds
      Bovey, F. A.; Yanari, S. S.
      Nature (London, United Kingdom) (1960), 186 (), 1042-4CODEN: NATUAS; ISSN:0028-0836.
      The shift of the optical spectral max. of absorbing solutes, Δλ (= λs - λ0, where λs and λ0 are the wave lengths of max. absorption in soln. and vapor phase, resp.) has been measured for C6H6, PhF, PhOH, and benzotrifluoride in perfluoropentane, cyclic perfluoro-C8-ether (manufd. by Minn. Mining and Manufg. Co.), Et2O, H2O, EtOH, iso-C8H18, CHCl3, CCl4, and petrolatum. No satisfactory math. relation between Δλ and n could be established and no agreement was found with the theoretical equations of Bayliss (CA 44, 9250h) or Longuet-Higgins and Pople (CA 51, 17439a).
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    18. 18
      (a) Rohrdanz, M. A.; Martins, K. M.; Herbert, J. M. A long-range-corrected density functional that performs well for both ground-state properties and time-dependent density functional theory excitation energies, including charge-transfer excited states. J. Chem. Phys. 2009, 130, 054112– 1-8,  DOI: 10.1063/1.3073302
      [Crossref], [PubMed], [CAS], Google Scholar
      18a
      A long-range-corrected density functional that performs well for both ground-state properties and time-dependent density functional theory excitation energies, including charge-transfer excited states
      Rohrdanz, Mary A.; Martins, Katie M.; Herbert, John M.
      Journal of Chemical Physics (2009), 130 (5), 054112/1-054112/8CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)
      We introduce a hybrid d. functional that asymptotically incorporates full Hartree-Fock exchange, based on the long-range-cor. exchange-hole model of Henderson et al. The performance of this functional, for ground-state properties and for vertical excitation energies within time-dependent d. functional theory, is systematically evaluated, and optimal values are detd. for the range-sepn. parameter, ω, and for the fraction of short-range Hartree-Fock exchange. We denote the new functional as LRC-ωPBEh, since it reduces to the std. PBEh hybrid functional (also known as PBE0 or PBE1PBE) for a certain choice of its two parameters. Upon optimization of these parameters against a set of ground- and excited-state benchmarks, the LRC-ωPBEh functional fulfills three important requirements: (i) It outperforms the PBEh hybrid functional for ground-state atomization energies and reaction barrier heights; (ii) it yields statistical errors comparable to PBEh for valence excitation energies in both small and medium-sized mols.; and (iii) its performance for charge-transfer excitations is comparable to its performance for valence excitations. LRC-ωPBEh, with the parameters detd. herein, is the first d. functional that satisfies all three criteria. Notably, short-range Hartree-Fock exchange appears to be necessary in order to obtain accurate ground-state properties and vertical excitation energies using the same value of ω. (c) 2009 American Institute of Physics.
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      .
      (b) Ditchfield, R.; Hehre, W. J.; Pople, J. A. Self-Consistent Molecular-Orbital Methods. IX. An Extended Gaussian-Type Basis for Molecular-Orbital Studies of Organic Molecules. J. Chem. Phys. 1971, 54, 724– 728,  DOI: 10.1063/1.1674902
      [Crossref], [CAS], Google Scholar
      18b
      Self-consistent molecular-orbital methods. IX. Extended Gaussian-type basis for molecular-orbital studies of organic molecules
      Ditchfield, R.; Hehre, Warren J.; Pople, John A.
      Journal of Chemical Physics (1971), 54 (2), 724-8CODEN: JCPSA6; ISSN:0021-9606.
      An extended basis set of at. functions expressed as fixed linear combinations of Gaussian functions is presented for H and the first-row atoms C to F. In this set. described as 4-31 G, each inner shell is represented by a single basis function taken as a sum of 4 Gaussians, and each valence orbital is split into inner and outer parts described by 3 and 1 Gaussian function, resp. The expansion coeffs. and Gaussian exponents are detd. by minimizing the total calcd. energy of the at. ground state. This basis set is then used in single-determinant MO studies of a group of small polyat. mols. Optimization of valence-shell scaling factors shows that considerable rescaling of at. functions occurs in mols., the largest effects being obsd. for H and C. However, the range of optimum scale factors for each atom is small enough to allow the selection of a std. mol. set. The use of this std. basis gives theoretical equil. geometries in reasonable agreement with expt.
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      .
      (c) Hehre, W. J.; Ditchfield, R.; Pople, J. A. Self—Consistent Molecular Orbital Methods. XII. Further Extensions of Gaussian—Type Basis Sets for Use in Molecular Orbital Studies of Organic Molecules. J. Chem. Phys. 1972, 56, 2257– 2261,  DOI: 10.1063/1.1677527
      [Crossref], [CAS], Google Scholar
      18c
      Self-consistent molecular orbital methods. XII. Further extensions of Gaussian-type basis sets for use in molecular orbital studies of organic molecules
      Hehre, W. J.; Ditchfield, R.; Pople, J. A.
      Journal of Chemical Physics (1972), 56 (5), 2257-61CODEN: JCPSA6; ISSN:0021-9606.
      Two extended basis sets (termed 5-31G and 6-31G) consisting of AO expressed as fixed linear combinations of Gaussian functions are presented for the 1st row atoms C to F. These basis functions are similar to the 4-31G set in that each valence shell is split into inner and outer parts described by 3 and 1 Gaussian function, resp. Inner shells are represented by a single basis function taken as a sum of 5 (5-31G) or 6 (6-31G) Guassians. Studies with a no. of polyat. mols. indicate a substantial lowering of calcd. total energies over the 4-31G set. Calcd. relative energies and equil. geometries do not appear to be altered significantly.
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      .
      (d) Shao, Y.; Gan, Z.; Epifanovsky, E.; Gilbert, A. T. B.; Wormit, M.; Kussmann, J.; Lange, A. W.; Behn, A.; Deng, J.; Feng, X.; Ghosh, D.; Goldey, M.; Horn, P. R.; Jacobson, L. D.; Kaliman, I.; Khaliullin, R. Z.; Kuś, T.; Landau, A.; Liu, J.; Proynov, E. I.; Rhee, Y. M.; Richard, R. M.; Rohrdanz, M. A.; Steele, R. P.; Sundstrom, E. J.; Woodcock, H. L.; Zimmerman, P. M.; Zuev, D.; Albrecht, B.; Alguire, E.; Austin, B.; Beran, G. J. O.; Bernard, Y. A.; Berquist, E.; Brandhorst, K.; Bravaya, K. B.; Brown, S. T.; Casanova, D.; Chang, C.-M.; Chen, Y.; Chien, S. H.; Closser, K. D.; Crittenden, D. L.; Diedenhofen, M.; DiStasio, R. A.; Do, H.; Dutoi, A. D.; Edgar, R. G.; Fatehi, S.; Fusti-Molnar, L.; Ghysels, A.; Golubeva-Zadorozhnaya, A.; Gomes, J.; Hanson-Heine, M. W. D.; Harbach, P. H. P.; Hauser, A. W.; Hohenstein, E. G.; Holden, Z. C.; Jagau, T.-C.; Ji, H.; Kaduk, B.; Khistyaev, K.; Kim, J.; Kim, J.; King, R. A.; Klunzinger, P.; Kosenkov, D.; Kowalczyk, T.; Krauter, C. M.; Lao, K. U.; Laurent, A. D.; Lawler, K. V.; Levchenko, S. V.; Lin, C. Y.; Liu, F.; Livshits, E.; Lochan, R. C.; Luenser, A.; Manohar, P.; Manzer, S. F.; Mao, S.-P.; Mardirossian, N.; Marenich, A. V.; Maurer, S. A.; Mayhall, N. J.; Neuscamman, E.; Oana, C. M.; Olivares-Amaya, R.; O’Neill, D. P.; Parkhill, J. A.; Perrine, T. M.; Peverati, R.; Prociuk, A.; Rehn, D. R.; Rosta, E.; Russ, N. J.; Sharada, S. M.; Sharma, S.; Small, D. W.; Sodt, A.; Stein, T.; Stück, D.; Su, Y.-C.; Thom, A. J. W.; Tsuchimochi, T.; Vanovschi, V.; Vogt, L.; Vydrov, O.; Wang, T.; Watson, M. A.; Wenzel, J.; White, A.; Williams, C. F.; Yang, J.; Yeganeh, S.; Yost, S. R.; You, Z.-Q.; Zhang, I. Y.; Zhang, X.; Zhao, Y.; Brooks, B. R.; Chan, G. K. L.; Chipman, D. M.; Cramer, C. J.; Goddard, W. A.; Gordon, M. S.; Hehre, W. J.; Klamt, A.; Schaefer, H. F.; Schmidt, M. W.; Sherrill, C. D.; Truhlar, D. G.; Warshel, A.; Xu, X.; Aspuru-Guzik, A.; Baer, R.; Bell, A. T.; Besley, N. A.; Chai, J.-D.; Dreuw, A.; Dunietz, B. D.; Furlani, T. R.; Gwaltney, S. R.; Hsu, C.-P.; Jung, Y.; Kong, J.; Lambrecht, D. S.; Liang, W.; Ochsenfeld, C.; Rassolov, V. A.; Slipchenko, L. V.; Subotnik, J. E.; Van Voorhis, T.; Herbert, J. M.; Krylov, A. I.; Gill, P. M. W.; Head-Gordon, M. Advances in molecular quantum chemistry contained in the Q-Chem 4 program package. Mol. Phys. 2015, 113, 184– 215,  DOI: 10.1080/00268976.2014.952696
      [Crossref], [CAS], Google Scholar
      18d
      Advances in molecular quantum chemistry contained in the Q-Chem 4 program package
      Shao, Yihan; Gan, Zhengting; Epifanovsky, Evgeny; Gilbert, Andrew T. B.; Wormit, Michael; Kussmann, Joerg; Lange, Adrian W.; Behn, Andrew; Deng, Jia; Feng, Xintian; Ghosh, Debashree; Goldey, Matthew; Horn, Paul R.; Jacobson, Leif D.; Kaliman, Ilya; Khaliullin, Rustam Z.; Kus, Tomasz; Landau, Arie; Liu, Jie; Proynov, Emil I.; Rhee, Young Min; Richard, Ryan M.; Rohrdanz, Mary A.; Steele, Ryan P.; Sundstrom, Eric J.; Woodcock, H. Lee, III; Zimmerman, Paul M.; Zuev, Dmitry; Albrecht, Ben; Alguire, Ethan; Austin, Brian; Beran, Gregory J. O.; Bernard, Yves A.; Berquist, Eric; Brandhorst, Kai; Bravaya, Ksenia B.; Brown, Shawn T.; Casanova, David; Chang, Chung-Min; Chen, Yunquing; Chien, Siu Hung; Closser, Kristina D.; Crittenden, Deborah L.; Diedenhofen, Michael; DiStasio, Robert A., Jr.; Do, Hainam; Dutoi, Anthony D.; Edgar, Richard G.; Fatehi, Shervin; Fusti-Molnar, Laszlo; Ghysels, An; Golubeva-Zadorozhnaya, Anna; Gomes, Joseph; Hanson-Heine, Magnus W. D.; Harbach, Philipp H. P.; Hauser, Andreas W.; Hohenstein, Edward G.; Holden, Zachary C.; Jagau, Thomas-C.; Ji, Hyunjun; Kaduk, Ben; Khistyaev, Kirill; Kim, Jaehoon; Kim, Jihan; King, Rollin A.; Klunzinger, Phil; Kosenkov, Dmytro; Kowalczyk, Tim; Krauter, Caroline M.; Lao, Ka Un; Laurent, Adele; Lawler, Keith V.; Levchenko, Sergey V.; Lin, Ching Yeh; Liu, Fenglai; Livshits, Ester; Lochan, Rohini C.; Luenser, Arne; Manohar, Prashant; Manzer, Samuel F.; Mao, Shan-Ping; Mardirossian, Narbe; Marenich, Aleksandr V.; Maurer, Simon A.; Mayhall, Nicholas J.; Neuscamman, Eric; Oana, C. Melania; Olivares-Amaya, Roberto; O'Neill, Darragh P.; Parkhill, John A.; Perrine, Trilisa M.; Peverati, Roberto; Prociuk, Alexander; Rehn, Dirk R.; Rosta, Edina; Russ, Nicholas J.; Sharada, Shaama M.; Sharma, Sandeep; Small, David W.; Sodt, Alexander; Stein, Tamar; Stuck, David; Su, Yu-Chuan; Thom, Alex J. W.; Tsuchimochi, Takashi; Vanovschi, Vitalii; Vogt, Leslie; Vydrov, Oleg; Wang, Tao; Watson, Mark A.; Wenzel, Jan; White, Alec; Williams, Christopher F.; Yang, Jun; Yeganeh, Sina; Yost, Shane R.; You, Zhi-Qiang; Zhang, Igor Ying; Zhang, Xing; Zhao, Yan; Brooks, Bernard R.; Chan, Garnet K. L.; Chipman, Daniel M.; Cramer, Christopher J.; Goddard, William A., III; Gordon, Mark S.; Hehre, Warren J.; Klamt, Andreas; Schaefer, Henry F., III; Schmidt, Michael W.; Sherrill, C. David; Truhlar, Donald G.; Warshel, Arieh; Xu, Xin; Aspuru-Guzik, Alan; Baer, Roi; Bell, Alexis T.; Besley, Nicholas A.; Chai, Jeng-Da; Dreuw, Andreas; Dunietz, Barry D.; Furlani, Thomas R.; Gwaltney, Steven R.; Hsu, Chao-Ping; Jung, Yousung; Kong, Jing; Lambrecht, Daniel S.; Liang, WanZhen; Ochsenfeld, Christian; Rassolov, Vitaly A.; Slipchenko, Lyudmila V.; Subotnik, Joseph E.; Van Voorhis, Troy; Herbert, John M.; Krylov, Anna I.; Gill, Peter M. W.; Head-Gordon, Martin
      Molecular Physics (2015), 113 (2), 184-215CODEN: MOPHAM; ISSN:0026-8976. (Taylor & Francis Ltd.)
      A review. A summary of the tech. advances that are incorporated in the fourth major release of the Q-Chem quantum chem. program is provided, covering approx. the last seven years. These include developments in d. functional theory methods and algorithms, NMR (NMR) property evaluation, coupled cluster and perturbation theories, methods for electronically excited and open-shell species, tools for treating extended environments, algorithms for walking on potential surfaces, anal. tools, energy and electron transfer modeling, parallel computing capabilities, and graphical user interfaces. In addn., a selection of example case studies that illustrate these capabilities is given. These include extensive benchmarks of the comparative accuracy of modern d. functionals for bonded and non-bonded interactions, tests of attenuated second order Moller-Plesset (MP2) methods for intermol. interactions, a variety of parallel performance benchmarks, and tests of the accuracy of implicit solvation models. Some specific chem. examples include calcns. on the strongly correlated Cr2 dimer, exploring zeolite-catalyzed ethane dehydrogenation, energy decompn. anal. of a charged ter-mol. complex arising from glycerol photoionisation, and natural transition orbitals for a Frenkel exciton state in a nine-unit model of a self-assembling nanotube.
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      .
      (e) Eng, J.; Laidlaw, B. A.; Penfold, T. J. On the geometry dependence of tuned-range separated hybrid functionals. J. Comp. Chem. 2019, 40, 2191– 2199,  DOI: 10.1002/jcc.25868
      [Crossref], [PubMed], [CAS], Google Scholar
      18e
      On the geometry dependence of tuned-ranged separated hybrid functionals
      Eng, Julien; Laidlaw, Beth A.; Penfold, Thomas J.
      Journal of Computational Chemistry (2019), 40 (25), 2191-2199CODEN: JCCHDD; ISSN:0192-8651. (John Wiley & Sons, Inc.)
      Mols. and materials that absorb and/or emit light form a central part of the daily lives. Consequently, a description of their excited-state properties plays a crucial role in designing new mols. and materials with enhanced properties. Due to its favorable balance between high computational efficiency and accuracy, time-dependent d. functional theory (TDDFT) is often a method of choice for characterizing these properties. However, within std. approxns. to the exchange-correlation functional, it remains challenging to achieve a balanced description of all excited states, esp. for those exhibiting charge-transfer (CT) characteristics. The authors have applied 2 approaches, namely, the optimal tuning and triplet tuning methods, for a nonempirical definition of range-sepd. functionals to improve the description of excited states within TDDFT. This is applied to study the CT properties of 2 thermally activated delayed fluorescence emitters, namely, PTZ-DBTO2 and TAT-3DBTO2. The authors demonstrate the connection between the 2 methods, the performance of each in the presence on multiple excited states of different characters and the geometry dependence of each method esp. relevant in the context of developing size-consistent potential energy surfaces. © 2019 Wiley Periodicals, Inc.
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      .
      (f) Eng, J.; Hagon, J.; Penfold, T. J. D-A3 TADF emitters: the role of the density of states for achieving faster triplet harvesting rates. J. Mater. Chem. C 2019, 7, 12942– 12952,  DOI: 10.1039/C9TC02561H
      [Crossref], [CAS], Google Scholar
      18f
      D-A3 TADF emitters: the role of the density of states for achieving faster triplet harvesting rates
      Eng, Julien; Hagon, Jerry; Penfold, Thomas James
      Journal of Materials Chemistry C: Materials for Optical and Electronic Devices (2019), 7 (41), 12942-12952CODEN: JMCCCX; ISSN:2050-7534. (Royal Society of Chemistry)
      The triplet harvesting rate in purely org. materials based upon Thermally Activated Delayed Fluorescence (TADF) is critically important for achieving high performance Org. Light Emitting Diodes (OLEDs). One of the major challenges that must be overcome in these materials is the weak spin orbit coupling which can lead to triplet harvesting rates that extend into the millisecond range. This causes poor roll-off in device efficiency at higher current densities. In this work, we study the excited state properties of a new TADF design strategy based upon the D-A3 approach. Using TAT-3DBTO2, composed of a rigid triazatruxene donor core with three dibenzothiophene-S,S-dioxide peripheral acceptors, we explain how exploiting the high d. of excited states and low lying conical intersections assocd. with this structure can achieve high-rates of triplet harvesting. However, we also demonstrate that excited state structural changes reduce the symmetry of the mol. and work against high triplet harvesting rates by causing localization of the excited state electronic structure and non-equivalence between the acceptors. Consequently, the fast initial reverse intersystem crossing (rISC) channels are replaced by undesirable slower rISC channels. Our results imply that it will be possible to engineer mols. where undesirable decay pathways are removed giving new perspectives for designing functional TADF mols.
      >> More from SciFinder ®
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      .
      (g) Hirata, S.; Head-Gordon, M. Time-dependent density functional theory within the Tamm–Dancoff approximation. Chem. Phys. Lett. 1999, 314, 291– 299,  DOI: 10.1016/S0009-2614(99)01149-5
      [Crossref], [CAS], Google Scholar
      18g
      Time-dependent density functional theory within the Tamm-Dancoff approximation
      Hirata, S.; Head-Gordon, M.
      Chemical Physics Letters (1999), 314 (3,4), 291-299CODEN: CHPLBC; ISSN:0009-2614. (Elsevier Science B.V.)
      A computationally simple method for mol. excited states, namely, the Tamm-Dancoff approxn. to time-dependent d. functional theory, is proposed and implemented. This method yields excitation energies for several closed- and open-shell mols. that are essentially of the same quality as those obtained from time-dependent d. functional theory itself, when the same exchange-correlation functional is used.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1MXnsl2rsr0%253D&md5=1b62f410de6c2a2193f1011d42f389c5
      .
      (h) Ufimtsev, I. S.; Martinez, T. J. Quantum Chemistry on Graphical Processing Units. 3. Analytical Energy Gradients, Geometry Optimization, and First Principles Molecular Dynamics. J. Chem. Theory Comput. 2009, 5, 2619– 2628,  DOI: 10.1021/ct9003004
      [ACS Full Text ACS Full Text], [CAS], Google Scholar
      18h
      Quantum Chemistry on Graphical Processing Units. 3. Analytical Energy Gradients, Geometry Optimization, and First Principles Molecular Dynamics
      Ufimtsev, Ivan S.; Martinez, Todd J.
      Journal of Chemical Theory and Computation (2009), 5 (10), 2619-2628CODEN: JCTCCE; ISSN:1549-9618. (American Chemical Society)
      We demonstrate that a video gaming machine contg. two consumer graphical cards can outpace a state-of-the-art quad-core processor workstation by a factor of more than 180× in Hartree-Fock energy + gradient calcns. Such performance makes it possible to run large scale Hartree-Fock and D. Functional Theory calcns., which typically require hundreds of traditional processor cores, on a single workstation. Benchmark Born-Oppenheimer mol. dynamics simulations are performed on two mol. systems using the 3-21G basis set - a hydronium ion solvated by 30 waters (94 atoms, 405 basis functions) and an aspartic acid mol. solvated by 147 waters (457 atoms, 2014 basis functions). Our GPU implementation can perform 27 ps/day and 0.7 ps/day of ab initio mol. dynamics simulation on a single desktop computer for these systems.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXhtVelurvJ&md5=f4e320ac3479e4b566a6b8bdb9e5add8
      .
      (i) Perdew, J. P.; Wang, Y. Accurate and simple analytic representation of the electron-gas correlation energy. Phys. Rev. B: Condens. Matter Mater. Phys. 1992, 45, 13244– 13249,  DOI: 10.1103/PhysRevB.45.13244
      [Crossref], [PubMed], [CAS], Google Scholar
      18i
      Accurate and simple analytic representation of the electron-gas correlation energy
      Perdew; Wang
      Physical review. B, Condensed matter (1992), 45 (23), 13244-13249 ISSN:0163-1829.
      There is no expanded citation for this reference.
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      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC2sflvVWktw%253D%253D&md5=fd10f1e0ef650cbd66f7747322127295
      .
      (j) Perdew, J. P.; Burke, K.; Ernzerhof, M. Generalized Gradient Approximation Made Simple. Phys. Rev. Lett. 1996, 77, 3865– 3868,  DOI: 10.1103/PhysRevLett.77.3865
      [Crossref], [PubMed], [CAS], Google Scholar
      18j
      Generalized gradient approximation made simple
      Perdew, John P.; Burke, Kieron; Ernzerhof, Matthias
      Physical Review Letters (1996), 77 (18), 3865-3868CODEN: PRLTAO; ISSN:0031-9007. (American Physical Society)
      Generalized gradient approxns. (GGA's) for the exchange-correlation energy improve upon the local spin d. (LSD) description of atoms, mols., and solids. We present a simple derivation of a simple GGA, in which all parameters (other than those in LSD) are fundamental consts. Only general features of the detailed construction underlying the Perdew-Wang 1991 (PW91) GGA are invoked. Improvements over PW91 include an accurate description of the linear response of the uniform electron gas, correct behavior under uniform scaling, and a smoother potential.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK28XmsVCgsbs%253D&md5=55943538406ee74f93aabdf882cd4630
      .
      (k) Binkley, J. S.; Pople, J. A.; Hehre, W. J. Self-consistent molecular orbital methods. 21. Small split-valence basis sets for first-row elements. J. Am. Chem. Soc. 1980, 102, 939– 947,  DOI: 10.1021/ja00523a008
      [ACS Full Text ACS Full Text], [CAS], Google Scholar
      18k
      Self-consistent molecular orbital methods. 21. Small split-valence basis sets for first-row elements
      Binkley, J. Stephen; Pople, John A.; Hehre, Warren J.
      Journal of the American Chemical Society (1980), 102 (3), 939-47CODEN: JACSAT; ISSN:0002-7863.
      Two new split-valence basis sets, termed 6-21G and 3-21G, are proposed for use in MO calcns. on mols. contg. first-row elements. The valence functions for the smaller representation (3-21G) were taken directly from the larger (6-21G), preventing their collapse inwards to make up for deficiencies in the inner-shell region. This is necessary to ensure a good description of bonding interactions which necessarily involve overlap of valence functions. Equil. geometries, vibrational frequencies, relative energies, and elec. dipole moments calcd. using the 3-21G basis set are nearly identical with those obtained from the larger 6-21G representation. Compared to expt. they are consistently superior to properties derived from the STO-3G minimal basis set, and of comparable quality to those obtained from the larger 4-21G and 4-31G representations. One notable exception is that the 4-31G basis set yields hydrogenation energies in significantly better agreement with expt. than those obtained from 3-21G. The 3-21G basis set comprises the same no. of primitive Gaussian functions as STO-3G (although nearly twice the no. of basis functions) and should be nearly as efficient computationally as that representation for applications which require evaluation of energy derivs. as well as the energy itself (e.g., detn. of equil. geometry and calcn. of vibrational frequencies). It is less costly to apply than either the 4-21G or 4-31G split-valence basis sets, and in those areas where the performance of the two is comparable it would appear to be the method of choice.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL3cXpvFylsA%253D%253D&md5=bb6510162ac94c836abf1abacbfad1f6
      .
      (l) Gordon, M. S.; Binkley, J. S.; Pople, J. A.; Pietro, W. J.; Hehre, W. J. Self-consistent molecular-orbital methods. 22. Small split-valence basis sets for second-row elements. J. Am. Chem. Soc. 1982, 104, 2797– 2803,  DOI: 10.1021/ja00374a017
      [ACS Full Text ACS Full Text], [CAS], Google Scholar
      18l
      Self-consistent molecular-orbital methods. 22. Small split-valence basis sets for second-row elements
      Gordon, Mark S.; Binkley, J. Stephen; Pople, John A.; Pietro, William J.; Hehre, Warren J.
      Journal of the American Chemical Society (1982), 104 (10), 2797-803CODEN: JACSAT; ISSN:0002-7863.
      Two new split-valence basis sets, termed 6-21G and 3-21G (B. et. al., 1980) for MO calcns on 1st-row element compds. are extended through the 2nd row. Equil. geometries, vibrational frequencies, relative energies, and elec. dipole moments calcd. with the use of the 3-21G basis set for a no. of mols. contg. 2nd-row atoms are nearly identical with those obtained from the larger 6-21G representation. Compared to expt. they are consistently superior to properties derived from the STO-3G minimal basis set, and of comparable quality to those obtained from the large 4-31G split-valence representation. The 3-21G set is less costly to apply than the 4-31G basis set, and would appear to be the method of choice for split-valence level Hartree-Fock calcns. on moderately sized mols.
      >> More from SciFinder ®
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      .
      (m) Grimme, S.; Antony, J.; Ehrlich, S.; Krieg, H. A consistent and accurate ab initio parametrization of density functional dispersion correction (DFT-D) for the 94 elements H-Pu. J. Chem. Phys. 2010, 132, 154104– 1-19,  DOI: 10.1063/1.3382344
      [Crossref], [PubMed], [CAS], Google Scholar
      18m
      A consistent and accurate ab initio parametrization of density functional dispersion correction (DFT-D) for the 94 elements H-Pu
      Grimme, Stefan; Antony, Jens; Ehrlich, Stephan; Krieg, Helge
      Journal of Chemical Physics (2010), 132 (15), 154104/1-154104/19CODEN: JCPSA6; ISSN:0021-9606. (American Institute of Physics)
      The method of dispersion correction as an add-on to std. Kohn-Sham d. functional theory (DFT-D) has been refined regarding higher accuracy, broader range of applicability, and less empiricism. The main new ingredients are atom-pairwise specific dispersion coeffs. and cutoff radii that are both computed from first principles. The coeffs. for new eighth-order dispersion terms are computed using established recursion relations. System (geometry) dependent information is used for the first time in a DFT-D type approach by employing the new concept of fractional coordination nos. (CN). They are used to interpolate between dispersion coeffs. of atoms in different chem. environments. The method only requires adjustment of two global parameters for each d. functional, is asymptotically exact for a gas of weakly interacting neutral atoms, and easily allows the computation of at. forces. Three-body nonadditivity terms are considered. The method has been assessed on std. benchmark sets for inter- and intramol. noncovalent interactions with a particular emphasis on a consistent description of light and heavy element systems. The mean abs. deviations for the S22 benchmark set of noncovalent interactions for 11 std. d. functionals decrease by 15%-40% compared to the previous (already accurate) DFT-D version. Spectacular improvements are found for a tripeptide-folding model and all tested metallic systems. The rectification of the long-range behavior and the use of more accurate C6 coeffs. also lead to a much better description of large (infinite) systems as shown for graphene sheets and the adsorption of benzene on an Ag(111) surface. For graphene it is found that the inclusion of three-body terms substantially (by about 10%) weakens the interlayer binding. We propose the revised DFT-D method as a general tool for the computation of the dispersion energy in mols. and solids of any kind with DFT and related (low-cost) electronic structure methods for large systems. (c) 2010 American Institute of Physics.
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      .
      (n) Grimme, S.; Ehrlich, S.; Goerigk, L. Effect of the damping function in dispersion corrected density functional theory. J. Comput. Chem. 2011, 32, 1456– 1465,  DOI: 10.1002/jcc.21759
      [Crossref], [PubMed], [CAS], Google Scholar
      18n
      Effect of the damping function in dispersion corrected density functional theory
      Grimme, Stefan; Ehrlich, Stephan; Goerigk, Lars
      Journal of Computational Chemistry (2011), 32 (7), 1456-1465CODEN: JCCHDD; ISSN:0192-8651. (John Wiley & Sons, Inc.)
      It is shown by an extensive benchmark on mol. energy data that the math. form of the damping function in DFT-D methods has only a minor impact on the quality of the results. For 12 different functionals, a std. "zero-damping" formula and rational damping to finite values for small interat. distances according to Becke and Johnson (BJ-damping) has been tested. The same (DFT-D3) scheme for the computation of the dispersion coeffs. is used. The BJ-damping requires one fit parameter more for each functional (three instead of two) but has the advantage of avoiding repulsive interat. forces at shorter distances. With BJ-damping better results for nonbonded distances and more clear effects of intramol. dispersion in four representative mol. structures are found. For the noncovalently-bonded structures in the S22 set, both schemes lead to very similar intermol. distances. For noncovalent interaction energies BJ-damping performs slightly better but both variants can be recommended in general. The exception to this is Hartree-Fock that can be recommended only in the BJ-variant and which is then close to the accuracy of cor. GGAs for non-covalent interactions. According to the thermodn. benchmarks BJ-damping is more accurate esp. for medium-range electron correlation problems and only small and practically insignificant double-counting effects are obsd. It seems to provide a phys. correct short-range behavior of correlation/dispersion even with unmodified std. functionals. In any case, the differences between the two methods are much smaller than the overall dispersion effect and often also smaller than the influence of the underlying d. functional. © 2011 Wiley Periodicals, Inc.; J. Comput. Chem., 2011.
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    19. 19
      Ayitou, A. J.; Fukuhara, G.; Kumarasamy, E.; Inoue, Y.; Sivaguru, J. Enantiospecific Photochemical Transformations under Elevated Pressure. Chem. - Eur. J. 2013, 19, 4327– 4334,  DOI: 10.1002/chem.201203665
      [Crossref], [PubMed], [CAS], Google Scholar
      19
      Enantiospecific Photochemical Transformations under Elevated Pressure
      Ayitou, Anoklase J.-L.; Fukuhara, Gaku; Kumarasamy, Elango; Inoue, Yoshihisa; Sivaguru, J.
      Chemistry - A European Journal (2013), 19 (13), 4327-4334CODEN: CEUJED; ISSN:0947-6539. (Wiley-VCH Verlag GmbH & Co. KGaA)
      Enantiospecific axial-to-point chiral transfer in light-induced transformations was efficient under elevated pressure at high temps. Model photoreactions with atropisomeric compds. showed higher enantioselectivity in the photoproducts under elevated pressure. The ee values in the photoproducts were rationalized based on the increased stability of optically pure atropisomeric compds. at elevated pressure, even at high temps.
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    • UV/vis spectra of the compound 1 under high pressure and difference of electronic associated to the most absorbing transition (PDF)


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