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Self-Healing Amorphous Polymers with Room-Temperature Phosphorescence Enabled by Boron-Based Dative Bonds
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  • Qi Wu
    Qi Wu
    State Key Laboratory of Polymer Materials Engineering, College of Polymer Science and Engineering, Sichuan University, Chengdu 610065, China
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  • Hui Xiong
    Hui Xiong
    State Key Laboratory of Polymer Materials Engineering, College of Polymer Science and Engineering, Sichuan University, Chengdu 610065, China
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  • Yong Zhu
    Yong Zhu
    State Key Laboratory of Polymer Materials Engineering, College of Polymer Science and Engineering, Sichuan University, Chengdu 610065, China
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  • Xiancheng Ren
    Xiancheng Ren
    State Key Laboratory of Polymer Materials Engineering, College of Polymer Science and Engineering, Sichuan University, Chengdu 610065, China
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  • Lin-Lin Chu
    Lin-Lin Chu
    Physics Department & Shanghai Key Laboratory of Magnetic Resonance, School of Physics and Materials Science, East China Normal University, Shanghai 200062, China
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  • Ye-Feng Yao
    Ye-Feng Yao
    Physics Department & Shanghai Key Laboratory of Magnetic Resonance, School of Physics and Materials Science, East China Normal University, Shanghai 200062, China
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    Orcidhttp://orcid.org/0000-0002-6274-2048
  • Guangsu Huang
    Guangsu Huang
    State Key Laboratory of Polymer Materials Engineering, College of Polymer Science and Engineering, Sichuan University, Chengdu 610065, China
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  • Jinrong Wu*
    Jinrong Wu
    State Key Laboratory of Polymer Materials Engineering, College of Polymer Science and Engineering, Sichuan University, Chengdu 610065, China
    *E-mail: [email protected]
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    Orcidhttp://orcid.org/0000-0002-5329-5522
Open PDFSupporting Information (3)

ACS Applied Polymer Materials

Cite this: ACS Appl. Polym. Mater. 2020, 2, 2, 699–705
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https://doi.org/10.1021/acsapm.9b01027
Published December 18, 2019

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Abstract

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Dative bonds are crucial for room-temperature phosphorescence (RTP) of metal complexes, which are nevertheless of high cost and toxicity. Here, we develop a class of amorphous RTP polymers based on nonmetal dative bonds through copolymerizing vinylphenylboronic acid and acrylamide derivatives. Nonmetal dative bonds, formed between boron and nitrogen/oxygen atoms, can populate triplet excitons through charge transfer and immobilize phosphors to suppress nonradiative relaxation, leading to effective RTP lifetime in air. Moreover, the dynamic nature of the dative bonds enables self-healing and anticounterfeiting abilities of the RTP polymers. The concept of designing nonmetal dative bonds can widely expand the horizon and application of RTP polymers.

Copyright © 2019 American Chemical Society

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Introduction

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Compared with traditional organometallic phosphors, completely metal-free organic polymers with room-temperature phosphorescence (RTP) have advantages of low cost, facile preparation, and good biocompatibility. (1) Moreover, RTP polymers are featured by long-lived triplet excitons and large Stokes shifts and thus hold great promise in applications such as in displaying, bioimaging, data storage, encryption, and so forth. (2−5) Both populating the triplet excitons through intersystem crossing (ISC) and inhibiting the nonradiative relaxation process should be considered when designing pure organic RTP materials. (6,7) Accordingly, many fascinating polymer-based RTP materials have been designed on account of two strategies: (i) Small molecule phosphors are embedded in the rigid environment of a polymer matrix, such as poly(methyl methacrylate), (8,9) poly(vinyl alcohol), (10,11) poly(lactic acid), (12,13) and so on. (ii) Functionalized organic luminophores are coupled with polymer chains to engender RTP emission, and RTP emission is strengthened by cross-linking, (14,15) hydrogen bonding, (16,17) host–guest interaction, (18) liquid crystals, (19) nanoparticles, (20,21) the heavy-atom effect, (22,23) and so on.
Despite significant progresses in metal-free RTP polymers, the current-state-of-art materials and devices on phosphorescence are usually based on metal complexes. Metal–ligand coordination affords charge transfer to promote ISC, mix singlet and triplet excitons, and improve the rate of phosphorescence decay. (24,25) Metals have also been coordinated onto polymers to generate phosphorescence. (26,27) However, since the metal-containing phosphors have the drawbacks of high cost, toxicity, and difficulty of preparation, it is highly desirable to develop non-metal-based dative bonds in RTP polymers. Boron, an electron-deficient element, exhibits a tendency to accept electron donor species to form dative bonds and Lewis pairs. (28) B–N/B–O dative bonds have been widely used in self-healing materials, (29,30) organic cages, (31,32) crystals, (33,34) and so forth. Boron-based RTP materials have attracted much attention in recent years. Difluoroboron β-diketonate derivatives as the first polymeric RTP material have been studied since 2007, but most of them are highly sensitive to oxygen. (35,36) Some crystalline small molecules of phenylboronic acid/ester also show RTP emission with long lifetime due to their special molecular configuration, molecular packing structures, and intermolecular interactions. (37−40) It is found that 2,4-difluorophenylboronic acid crystal has the longest lifetime among the reported single-component pure organic phosphors. (41) However, crystallization usually requires strict control on the growth conditions, and it is difficult to obtain bulk RTP materials, restricting the practical application of RTP materials. Being aware of the low stability in air or the requirement to form crystals of current boron-based RTP materials, introducing stable boron-based dative bonds into easily accessible polymers may offer an alternative strategy to overcome these drawbacks.
Herein, we develop a class of amorphous RTP polymers by radical copolymerization of vinylphenylboronic acid (VPBA) and acrylamide derivatives. In our materials, boron atoms mainly form dative bonds with nitrogen atoms as well as the coexistence of some B–O dative bonds. Charge transfer in dative bonds can enhance the probability of ISC process to populate the triplet excitons; meanwhile, the possible motions of phosphors can be effectively immobilized by dative bonds, which strongly increase RTP signals. In addition, the dynamic networks endow the materials with water-enabled self-healing ability, and the RTP property provides a platform for potential applications like anticounterfeiting. To the best of our knowledge, this is the first reported amorphous RTP polymer based on non-metal dative bonds, which will expand the field of pure organic RTP materials.

Results and Discussion

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The fabrication of 4-vinylphenylboronic acid/acrylamide (4-VPBA/AA) copolymers (p-BAA) involves two steps. In the first step, the radical copolymerization of 4-VPBA and AA at different molar ratios generates white p-BAA powders (p-BAA-P), as shown in Scheme S1 and Table S1. The appearance of aromatic protons in proton nuclear magnetic resonance (1H NMR) and B–O stretching peak (1346 cm–1) in Fourier transform infrared spectroscopy (FTIR) suggests the successful introduction of phenylboronic acid groups onto the main chains (Figures S1 and S2a). (42,43) In the second step, transparent p-BAA films (p-BAA-F) are prepared by dissolving p-BAA-P in water followed by a film casting process. Both a signal between 30 and 35 ppm in solid-state 11B NMR (Figure 1b) and a peak above 8 ppm in solid-state 1H NMR (Figure S3) cannot be detected, indicating that boroxines are not formed during film formation. (44,45)

Figure 1

Figure 1. Structural characterization of p-BAA with 4-VPBA/AA molar ratio of 1/10: FTIR spectra (a), solid-state 11B spectra (b), and B 1s XPS spectra (c). Schematic process to fabricate p-BAA-P and p-BAA-F (d).

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Although the molecular structures remain unchanged during the film casting process and both p-BAA-P and p-BAA-F are amorphous (Figure S4), the interactions between p-BAA molecules are significantly different. Such differences are examined with FTIR, solid-state 11B NMR, and X-ray photoelectron spectroscopy (XPS). The absorption of amide I and II bands occurs at lower frequencies in p-BAA-F than that in p-BAA-P (Figure 1a and Figure S2b), showing that p-BAA-F has the higher degree of hydrogen bonding and thus a stronger hydrogen-bonded environment than p-BAA-P. (46) The symmetrical narrow peak in solid-state 11B NMR spectra (Figure 1b) demonstrates the tetrahedral four-coordinated structure of boron atoms. (47) The four-coordinated boron centers of p-BAA-P and p-BAA-F can be further proved by XPS. The B 1s signal (Figure 1c) can be fitted with two peaks with binding energies at 191.3 and 190.8 eV, corresponding to B–O and B–N dative bonds, respectively. (48−50) These binding energies of B 1s are lower than the value of B 1s (191.6 eV) of analogous phenylboronic acid in polymer without coordinative interactions; this indicates the enhanced electron density localized on the boron atom upon forming coordinative interactions. (51,52) After film casting, the component of B–N dative bond increases while that of B–O dative bond decreases, suggesting the transformation from B–O to more stable B–N dative bonds. (53) Meanwhile, the relative XPS results of N 1s and O 1s also confirm this transformation (Figures S5 and S6). In conclusion, the casted film shows stronger hydrogen bonding and more stable dative bonding than the powder, which leads to tighter and more rigid structures to realize phosphorescence (Figure 1d). Thus, the film samples are investigated in the following sections.
As shown in Figure 2a, p-BAA not only exhibits fluorescence emission (λmax = 409 nm) with the photoluminescence quantum yield of 21.59% but also shows phosphorescence emission (λmax = 477 nm) at 360 nm excitation. With the feed molar ratio of 4-VPBA/AA decrease, the actual VPBA unit content also decreases, and the phosphorescence lifetime increases at first and then decreases. When the feed molar ratio of 4-VPBA/AA is 1/50, p-BAA has the longest phosphorescence lifetime (0.351 s), as shown in Figure 2c as well as Tables S2 and S3. Therefore, the ratio of 1/50 is the best candidate for following copolymerization. (54)

Figure 2

Figure 2. (a) Photoluminescence excitation (black), fluorescence (red), and RTP (blue) spectra of BAAs. Inset: luminescence decay lifetime at the excitation peak of 355 nm. (b) Luminescence photographs of BAA films under sunlight and 365 nm UV irradiation and after removal of UV irradiation. (c) RTP lifetimes and actual VPBA unit contents of p-BAA with different feed molar ratios. (d) XRD patterns of BAAs.

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To evaluate whether the position of boronic acid group (BA) on the benzene ring can affect RTP ability, we prepare m-BAA and o-BAA bearing BA on the meta- and ortho-positions, respectively. The experimental details and structure are shown in Scheme S1 and Figure S7. All the BAAs with different BA positions show blue emission in air under 365 nm UV irradiation and green afterglow that lasts over 4 s by the naked eye after removal of the UV irradiation, as shown in Figure 2b and Movie S1. From the photophysical spectra (Figure 2a and Table S4), m-BAA and o-BAA, like p-BAA, exhibit both fluorescence and RTP with lifetimes over 0.3 s, indicating that the RTP property of BAAs is barely influenced by the BA position. X-ray diffraction (XRD) and XPS measurements reveal that both m-BAA and o-BAA are amorphous with four-coordinate boron center and the component of B–N dative bond is more than that of B–O dative bond (Figure 2d and Figure S8), similar to p-BAA.
To examine the role of dative bonds in the RTP property, N,N′-dimethylacrylamide (DMA, analogous structure to AA but with negligible hydrogen bonding (55)) and styrene (St, rigid molecular environment after polymerization (56)) are selected as comonomers to copolymerize with VPBA, generating vinylphenylboronic acid/N,N′-dimethylacrylamide copolymer (BAD) and vinylphenylboronic acid/styrene copolymer (BAS), respectively. The experimental details and chemical structure are shown in Scheme S2 as well as Figures S9 and S10. Although both BAD and BAS are amorphous (Figure S11), there is a huge distinction concerning the boron center between them. The B 1s of BAD can be fitted into two peaks with 191.3 and 190.5 eV, illustrating the boron in BAD is four-coordinated to form B–O and B–N dative bonds. The binding energy of B–N dative bond in BAD is lower than that in BAA, indicating that the more negative nitrogen atom in BAD leads to higher electron density of the boron atom (Figure 3a and Figure S12). Different from BAD, both B 1s and O 1s of BAS can be fitted by one peak at 191.6 and 532.2 eV, respectively, indicating the boron in BAS is not coordinated (Figure 3b and Figure S13). (57) Collectively, these results demonstrate that the dative-bonding network can be formed in BAD but not in BAS (Figure S14).

Figure 3

Figure 3. (a) Chemical structure, B 1s XPS spectra as well as photoluminescence excitation (black), fluorescence (red), and RTP (blue) spectra of p-BAD. Inset: luminescence decay lifetime at the excitation peak of 355 nm. (b) Chemical structure, B 1s XPS spectra as well as photoluminescence excitation (black) and fluorescence (red) spectra of BAS.

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Both BAD and BAS exhibit fluorescence emission, and BAS does not demonstrate RTP (Figure 3 and Figure S15). Unexpectedly, RTP with a wide wavenumber range can be observed in BAD (Table S5). The RTP appearance in BAD is inconsistent with the absence of RTP in covalently cross-linked structure formed by the phosphor and DMA. (58) Moreover, the RTP intensity of BAD is not reduced too much compared with that of BAA, though BAD lacks a strong rigid hydrogen-bonding network (Figure S16). The results reveal the network formed by dative bonds plays a crucial role in RTP.
UV–vis absorption spectra (Figure S17) show the intensity of the shoulder peak around 345 nm increases with increasing the concentration of BAA/BAD aqueous solutions, and the similar shoulder peak also exists in BAA/BAD solid samples. The shoulder peak is the characteristic of the charge transfer bands of dative bonds. (59) What is more, fluorescence spectra in different solvents (Figure S18) show the fluorescence bands of BAA/BAD solutions shift to red with increasing the polarity of solvents, demonstrating the charge transfer in dative bonds. (60) Charge transfer in dative bonds enhances the probability of spin–orbit coupling, thereby improving the rate of ISC to populate the triplet excitons. (61−63) Meanwhile, the dative bonding between phenylboronic acid and acrylamide groups can restrict the phosphors to reduce the nonradiative relaxation. (64−66) The combination of these two effects of dative bonds leads to pure organic RTP polymers. In addition, hydrogen bonding among polymer chains in BAA can suppress the motion of the phosphors and shield the quenchers, which increases the intensity and the lifetime of RTP. (67−69)
Based on the association/dissociation of the dynamic dative bonds and hydrogen bonds, BAA exhibits water-enabled healing properties, as shown in Figure 4 and Figure S19. A rectangular sample is cut into two separate pieces by a blade; the fractured surfaces of the pieces are wetted with water and brought back into contact at 40 °C. Amazingly, after healing for only 1 min, the two pieces are welded and can withstand the same weight as the sample before fracturing. Furthermore, after putting the healed sample under vacuum at 40 °C for 24 h, the blue emission in air under 365 nm UV light and green afterglow after the UV light is turned off can be observed at both the damaged and other positions, indicating the sample remains RTP property through recombination of the fractured network after healing.

Figure 4

Figure 4. Water-enabled self-healing ability of BAA. (a) Polarizing microscope maps of the fracture to trace the healing process: the original state after cut (top) and the healed state after 1 min (bottom). (b) The film of 0.2 g can sustain a weight of 200 g before and after healing. (c) Fluorescence and phosphorescence can be observed in the healed sample. (d) Schematic illustration of the water-enabled healing process: Free functional groups are generated with the assistance of water in the surface, and then hydrogen bonds and dative bonds are re-formed across the fracture after drying.

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Benefiting from the favorable water solubility and distinguishable RTP lifetime, BAAs can be potential candidates for anticounterfeiting applications, as shown in Figure 5. A flower is manually painted by two types of BAAs on a piece of nonfluorescent rice paper. Upon drying under vacuum, the flower is transparent under sunlight, while it shows slightly different blue colors between the bloom and stem under a 356 nm UV lamp. After removal of UV irradiation, the green RTP could be observed by the naked eye. If the flower is exposed to the relative humidity (RH) of 33%, it still shows blue colors under 365 nm UV light but becomes invisible after UV light off (Movie S2), which is due to the destruction of hydrogen-bonding networks and the circumstance change of boron centers by humidity, as revealed by FTIR, solid-state 11B NMR, and XPS (Figures S20–S22). If the flower is redried in a vacuum, the RTP property can be recovered, suggesting this humidity-responsive procedure is totally reversible.

Figure 5

Figure 5. Photographs of the flower after drying and wetting under sunlight, a 365 nm UV lamp, and the removal of the UV lamp.

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Conclusion

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In summary, we develop a series of pure organic RTP polymers utilizing boron-based dative bonds. The charge transfer in the dative bonds populates the triplet excitons through ISC; meanwhile, the dative bonds inhibit the motions of the phosphors, which leads to the RTP property. Moreover, the dynamic dative bonds as well as the hydrogen bonds afford the self-healing ability of the RTP materials, enabling recovery of both photophysical and mechanical properties after the material is damaged. The material is the first example of the amorphous RTP polymer based on nonmetal dative bonds involving boron atoms. This opens up a new horizon to design and construct completely organic RTP polymers, providing an attractive platform to develop RTP-based sensing, data encryption, and organic devices.

Experimental Section

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Synthesis

BAA, BAD, and BAS were fabricated by the radical copolymerization of VPBA and comonomers (AA, DMA, and St), respectively. The film samples were prepared by dissolution in the solvent followed by a film-casting process.

Characterization

The molecular weight was determined by using a Tosoh HIC-8320GPC with water as the eluent except BAS, which was measured with tetrahydrofuran as the eluent. FTIR spectra were recorded on a Thermo Scientific Nicolet iS50 FTIR by a transmission mode for powder samples and an attenuated total reflection mode for film samples at room temperature. 1H NMR spectra were measured by a Bruker AV III HD 400 MHz spectrometer with deuteroxide (D2O) as the solvent. Solid-state 11B NMR spectra and solid-state 1H NMR were recorded on a Bruker Avance 600 solid-state NMR spectrometer. XRD spectra were measured on an X-Pert diffractometer (Philips). XPS spectra were performed on an XSAM800 (Kratos) using a monochromatic Al Kα X-ray source radiation. UV–vis adsorption spectra were analyzed by using a UV–vis spectrometer (UV-3600, Shimadzu) on a water absorbance basis. Fluorescence excitation/emission spectra were performed by using a Fluorolog-3 spectrofluorometer (Horiba Jobin Yvon) with a 450 W xenon lamp as the excitation source and a picosecond photon detection module (PPD-850) as the detector. Phosphorescence emission spectra were performed by using a FluoroMaX-4P spectrofluorometer (Horiba Jobin Yvon) with a 25 W flash xenon lamp as the excitation source. The phosphorescence lifetime was measured on a Fluorolog-3 spectrofluorometer (Horiba Jobin Yvon) with a SpectraLED (355 nm, S-355) as the excitation source and a picosecond photon detection module (PPD-850) as the detector. The structures of self-healing process were characterized by a polarizing optical microscope (Olympus BX-51) at 40 °C in air.

Supporting Information

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The Supporting Information is available free of charge at https://pubs.acs.org/doi/10.1021/acsapm.9b01027.

  • Experimental details and additional discussion of BAA, BAD, and BAS, 1H NMR, solid-state 1H NMR, solid-state 11B NMR, FTIR, XPS, XRD, UV–vis, and photophysical properties (PDF)

  • Movie S1: RTP performance of BAAs (MP4)

  • Movie S2: RTP-based anticounterfeiting application of BAAs (MP4)

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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 Author
  • Authors
    • Qi Wu - State Key Laboratory of Polymer Materials Engineering, College of Polymer Science and Engineering, Sichuan University, Chengdu 610065, China
    • Hui Xiong - State Key Laboratory of Polymer Materials Engineering, College of Polymer Science and Engineering, Sichuan University, Chengdu 610065, China
    • Yong Zhu - State Key Laboratory of Polymer Materials Engineering, College of Polymer Science and Engineering, Sichuan University, Chengdu 610065, China
    • Xiancheng Ren - State Key Laboratory of Polymer Materials Engineering, College of Polymer Science and Engineering, Sichuan University, Chengdu 610065, China
    • Lin-Lin Chu - Physics Department & Shanghai Key Laboratory of Magnetic Resonance, School of Physics and Materials Science, East China Normal University, Shanghai 200062, China
    • Ye-Feng Yao - Physics Department & Shanghai Key Laboratory of Magnetic Resonance, School of Physics and Materials Science, East China Normal University, Shanghai 200062, China;  Orcidhttp://orcid.org/0000-0002-6274-2048
    • Guangsu Huang - State Key Laboratory of Polymer Materials Engineering, College of Polymer Science and Engineering, Sichuan University, Chengdu 610065, China
  • Notes
    The authors declare no competing financial interest.

Acknowledgments

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This work was supported by the National Natural Science Foundation of China (Grants 51873110 and 51673120).

Abbreviations

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VPBA

vinylphenylboronic acid

AA

acrylamide

DMA

N,N′-dimethylacrylamide

St

styrene

BA

phenylboronic acid

BAA

vinylphenylboronic acid/acrylamide copolymer

BAD

vinylphenylboronic acid/N,N′-dimethylacrylamide copolymer

BAS

vinylphenylboronic acid/styrene copolymer

RTP

room-temperature phosphorescence.

References

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This article references 69 other publications.

  1. 1
    Xu, H.; Chen, R.; Sun, Q.; Lai, W.; Su, Q.; Huang, W.; Liu, X. Recent progress in metal-organic complexes for optoelectronic applications. Chem. Soc. Rev. 2014, 43 (10), 3259– 3302,  DOI: 10.1039/C3CS60449G
    Google Scholar
    1
    Recent progress in metal-organic complexes for optoelectronic applications
    Xu, Hui; Chen, Runfeng; Sun, Qiang; Lai, Wenyong; Su, Qianqian; Huang, Wei; Liu, Xiaogang
    Chemical Society Reviews (2014), 43 (10), 3259-3302CODEN: CSRVBR; ISSN:0306-0012. (Royal Society of Chemistry)
    A review. The design and characterization of metal-org. complexes for optoelectronic applications is an active area of research. The metal-org. complex offers unique optical and electronic properties arising from the interplay between the inorg. metal and the org. ligand. The ability to modify chem. structure through control over metal-ligand interaction on a mol. level could directly impact the properties of the complex. When deposited in thin film form, this class of materials enable the fabrication of a wide variety of low-cost electronic and optoelectronic devices. These include light emitting diodes, solar cells, photodetectors, field-effect transistors as well as chem. and biol. sensors. Here we present an overview of recent development in metal-org. complexes with controlled mol. structures and tunable properties. Advances in extending the control of mol. structures to solid materials for energy conversion and information technol. applications will be highlighted.
  2. 2
    Xu, S.; Chen, R.; Zheng, C.; Huang, W. Excited State Modulation for Organic Afterglow: Materials and Applications. Adv. Mater. 2016, 28 (45), 9920– 9940,  DOI: 10.1002/adma.201602604
    Google Scholar
    2
    Excited State Modulation for Organic Afterglow: Materials and Applications
    Xu, Shen; Chen, Runfeng; Zheng, Chao; Huang, Wei
    Advanced Materials (Weinheim, Germany) (2016), 28 (45), 9920-9940CODEN: ADVMEW; ISSN:0935-9648. (Wiley-VCH Verlag GmbH & Co. KGaA)
    Org. afterglow materials, developed recently by breaking through the difficulties in modulating ultrafast-decayed excited states, exhibit ultralong-lived emission for persistent luminescence with lifetimes of several orders of magnitude longer than traditional fluorescent and phosphorescent emissions at room temp. Their exceptional properties, namely ultralong luminescent lifetime, large Stokes shifts, facile excited state transformation, and environmentally sensitive emission, have led to a diverse range of advanced optoelectronic applications. Here, the org. afterglow is reviewed from the perspective of fundamental concepts on both phenomenon and mechanism, examg. the tech. challenges in relation to excited state tuning and lifetime elongation. In particular, the advances in material design strategies that afford a large variety of org. afterglow materials for a broad utility in optoelectronics including lighting and displays, anti-counterfeiting, optical recording, chem. sensors and bio-imaging are highlighted.
  3. 3
    Ma, X.; Wang, J.; Tian, H. Assembling-Induced Emission: An Efficient Approach for Amorphous Metal-Free Organic Emitting Materials with Room-Temperature Phosphorescence. Acc. Chem. Res. 2019, 52 (3), 738– 748,  DOI: 10.1021/acs.accounts.8b00620
    Google Scholar
    3
    Assembling-Induced Emission: An Efficient Approach for Amorphous Metal-Free Organic Emitting Materials with Room-Temperature Phosphorescence
    Ma, Xiang; Wang, Jie; Tian, He
    Accounts of Chemical Research (2019), 52 (3), 738-748CODEN: ACHRE4; ISSN:0001-4842. (American Chemical Society)
    A review. Pure org. emitting materials with room-temp. phosphorescence (RTP), showing large Stokes shifts with long emitting lifetime, low prepn. cost, good processability, and wide applications in anal., bioimaging, org. light emitting diode, and so forth, were drawing great attentions recently. Related to the design strategy for metal-free RTP materials, the phosphors contg. heavy atoms (Br, I, etc.) and other heteroatoms (O, S, etc.) to facilitate the singlet-to-triplet intersystem crossing (ISC) to populate the triplet are usually employed. Besides this factor, the pathways of nonradiative relaxation are inhibited as much as possible. Cryst. packing was the commonly used strategy to engender the rigid environment to suppress the nonradiative decay, and thus to enhance the RTP emission. Crystal RTP materials might usually be provided with not good enough repeatability and processability, which would restrict their specific practical applications special for biosystem. Amorphous metal-free RTP materials could overcome such deficiencies. Great efforts were devoted to develop challengeable amorphous metal-free materials and expand their potential applications. The main focus is on the recent progress on amorphous pure org. RTP system, focusing on the rigid effect to restrict the nonradiative decay to induce or enhance the RTP emission via supramol. interactions such as host-guest interaction and H-bonding rigid matrix. Typical host-guest assembling and supramol. polymer systems, H-binding copolymers, and small mols. for RTP emission, as well as the heavy-atom free assembling systems for RTP emission are well illustrated in this Account. Some future perspectives and research direction of the area of pure org. RTP systems are given, such as enhancement of emission quantum yield, emission color tuning, possible device applications, and the remaining challenge. Based on these amorphous RTP material examples and beyond, the authors herein would like to conclude and propose a new concept as assembling-induced emission, the key thought of which systems is control mol. motions, then control emission via supramol. dynamic assembling. This assembling-induced emission strategy is applicable in many emissive assembling systems besides such amorphous RTP materials introduced in this Account. Hopefully this concept will be a helpful guide for understanding the emissive mechanism and constructing strategy of various emissive materials.
  4. 4
    Xiao, L.; Chen, Z.; Qu, B.; Luo, J.; Kong, S.; Gong, Q.; Kido, J. Recent Progresses on Materials for Electrophosphorescent Organic Light-Emitting Devices. Adv. Mater. 2011, 23 (8), 926– 952,  DOI: 10.1002/adma.201003128
    Google Scholar
    4
    Recent progresses on materials for electrophosphorescent organic light-emitting devices
    Xiao, Lixin; Chen, Zhijian; Qu, Bo; Luo, Jiaxiu; Kong, Sheng; Gong, Qihuang; Kido, Junji
    Advanced Materials (Weinheim, Germany) (2011), 23 (8), 926-952CODEN: ADVMEW; ISSN:0935-9648. (Wiley-VCH Verlag GmbH & Co. KGaA)
    A review. Although org. light-emitting devices were commercialized as flat panel displays since 1997, only singlet excitons were emitted. Full use of singlet and triplet excitons, electrophosphorescence, has attracted increasing attentions after the premier work made by Forrest, Thompson, and co-workers. In fact, red electrophosphorescent dye has already been used in sub-display of com. mobile phones since 2003. Highly efficient green phosphorescent dye is now undergoing of commercialization. Very recently, blue phosphorescence approaching the theor. efficiency also was achieved, which may overcome the final obstacle against the commercialization of full color display and white light sources from phosphorescent materials. Combining light out-coupling structures with highly efficient phosphors (shown in the table-of-contents image), white emission with an efficiency matching that of fluorescent tubes (90 lm/W) has now been realized. It is possible to tune the color to the true white region by changing to a deep blue emitter and corresponding wide gap host and transporting material for the blue phosphor. Recent progresses in red, green, blue, and white electrophosphorescent materials for OLEDs are reviewed, with special emphasis on blue electrophosphorescent materials.
  5. 5
    Wang, Q.; Dou, X.; Chen, X.; Zhao, Z.; Wang, S.; Wang, Y.; Sui, K.; Tan, Y.; Gong, Y.; Zhang, Y.; Yuan, W. Z. Reevaluating Protein Photoluminescence: Remarkable Visible Luminescence upon Concentration and Insight into the Emission Mechanism. Angew. Chem., Int. Ed. 2019, 58 (36), 12667– 12673,  DOI: 10.1002/anie.201906226
    Google Scholar
    5
    Reevaluating protein photoluminescence: Remarkable visible luminescence upon concentration and insight into the emission mechanism
    Wang, Qian; Dou, Xueyu; Chen, Xiaohong; Zhao, Zihao; Wang, Shuang; Wang, Yunzhong; Sui, Kunyan; Tan, Yeqiang; Gong, Yongyang; Zhang, Yongming; Yuan, Wang Zhang
    Angewandte Chemie, International Edition (2019), 58 (36), 12667-12673CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)
    It is a textbook knowledge that protein photoluminescence stems from the three arom. amino acid residues of tryptophan(Trp), tyrosine (Tyr), and phenylalanine (Phe), with predominant contributions from Trp. Recently, inspired by the intrinsic emission of nonarom. amino acids and poly(amino acids) in concd. solns. and solids, we revisited protein light emission using bovine serum albumin (BSA) as a model. BSA is virtually nonemissive in dil. solns. (≤0.1 mg mL-1), but highly luminescent upon concn. or aggregation, showing unique concn.-enhanced emission and aggregation-induced emission (AIE) characteristics. Notably, apart from well-documented UV luminescence, bright blue emission is clearly obsd. Furthermore, persistent room-temp. phosphorescence (p-RTP) is achieved even in the amorphous solids under ambient conditions. This visible emission can be rationalized by the clustering-triggered emission (CTE) mechanism. These findings not only provide an in-depth understanding of the emissive properties of proteins, but also hold strong implications for further elucidating the basis of tissue autofluorescence.
  6. 6
    Hirata, S. Recent Advances in Materials with Room-Temperature Phosphorescence: Photophysics for Triplet Exciton Stabilization. Adv. Opt. Mater. 2017, 5 (17), 1700116,  DOI: 10.1002/adom.201700116
    Google Scholar
    There is no corresponding record for this reference.
  7. 7
    Zhou, Q.; Wang, Z.; Dou, X.; Wang, Y.; Liu, S.; Zhang, Y.; Yuan, W. Z. Emission mechanism understanding and tunable persistent room temperature phosphorescence of amorphous nonaromatic polymers. Mater. Chem. Front. 2019, 3 (2), 257– 264,  DOI: 10.1039/C8QM00528A
    Google Scholar
    7
    Emission mechanism understanding and tunable persistent room temperature phosphorescence of amorphous nonaromatic polymers
    Zhou, Qing; Wang, Ziyi; Dou, Xueyu; Wang, Yunzhong; Liu, Saier; Zhang, Yongming; Yuan, Wang Zhang
    Materials Chemistry Frontiers (2019), 3 (2), 257-264CODEN: MCFAC5; ISSN:2052-1537. (Royal Society of Chemistry)
    Deciphering the emission mechanism of nonconventional luminogens and achieving persistent room temp. phosphorescence (p-RTP) from pure org. compds. have drawn increasing attention due to their significant fundamental importance and promising applications. Previous reports on nonconventional luminogens, however, mainly focus on fluorescence, while advances in pure org. p-RTP are generally restricted to arom. crystals or host-guest systems. Herein, we report the unique intrinsic emission and moreover p-RTP in amorphous nonarom. polymers of poly(acrylic acid) (PAA), polyacrylamide (PAM) and poly(N-isopropylacrylamide) (PNIPAM). These polymers are nonluminescent in dil. solns., while being highly emissive in concd. solns., nanosuspensions and solid powders/films. This can be rationalized by the clustering-triggered emission (CTE) mechanism, as supported by further thermoresponsive emission, cryogenic and aggregation-induced emission (AIE) expts., alongside single crystal anal. Furthermore, PAA and PAM solids under ambient conditions, and PNIPAM solids under vacuum or under nitrogen, demonstrate distinct p-RTP, which can be enhanced through further ionization or pressurization. These results not only refresh our understanding of the emission mechanism of nonarom. polymers, but also enable the facile fabrication and application of pure org. p-RTP luminogens from readily available compds., thus providing an important step forward in both nonconventional luminogens and p-RTP.
  8. 8
    Lee, D.; Bolton, O.; Kim, B. C.; Youk, J. H.; Takayama, S.; Kim, J. Room Temperature Phosphorescence of Metal-Free Organic Materials in Amorphous Polymer Matrices. J. Am. Chem. Soc. 2013, 135 (16), 6325– 6329,  DOI: 10.1021/ja401769g
    Google Scholar
    8
    Room Temperature Phosphorescence of Metal-Free Organic Materials in Amorphous Polymer Matrices
    Lee, Dongwook; Bolton, Onas; Kim, Byoung Choul; Youk, Ji Ho; Takayama, Shuichi; Kim, Jinsang
    Journal of the American Chemical Society (2013), 135 (16), 6325-6329CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)
    Developing metal-free org. phosphorescent materials is promising but challenging because achieving emissive triplet relaxation that outcompetes the vibrational loss of triplets, a key process to achieving phosphorescence, is difficult without heavy metal atoms. While recent studies reveal that bright room temp. phosphorescence can be realized in purely org. cryst. materials through directed halogen bonding, these org. phosphors still have limitations to practical applications due to the stringent requirement of high quality crystal formation. Here we report bright room temp. phosphorescence by embedding a purely org. phosphor into an amorphous glassy polymer matrix. Our study implies that the reduced beta (β)-relaxation of isotactic PMMA most efficiently suppresses vibrational triplet decay and allows the embedded org. phosphors to achieve a bright 7.5% phosphorescence quantum yield. We also demonstrate a microfluidic device integrated with a novel temp. sensor based on the metal-free purely org. phosphors in the temp.-sensitive polymer matrix. This unique system has many advantages: (i) simple device structures without feeding addnl. temp. sensing agents, (ii) bright phosphorescence emission, (iii) a reversible thermal response, and (iv) tunable temp. sensing ranges by using different polymers.
  9. 9
    Louis, M.; Thomas, H.; Gmelch, M.; Haft, A.; Fries, F.; Reineke, S. Blue-Light-Absorbing Thin Films Showing Ultralong Room-Temperature Phosphorescence. Adv. Mater. 2019, 31 (12), 1807887,  DOI: 10.1002/adma.201807887
    Google Scholar
    There is no corresponding record for this reference.
  10. 10
    Su, Y.; Phua, S. Z. F.; Li, Y.; Zhou, X.; Jana, D.; Liu, G.; Lim, W. Q.; Ong, W. K.; Yang, C.; Zhao, Y. Ultralong room temperature phosphorescence from amorphous organic materials toward confidential information encryption and decryption. Sci. Adv. 2018, 4 (5), eaas9732  DOI: 10.1126/sciadv.aas9732
    Google Scholar
    There is no corresponding record for this reference.
  11. 11
    Li, Q.; Zhou, M.; Yang, M.; Yang, Q.; Zhang, Z.; Shi, J. Induction of long-lived room temperature phosphorescence of carbon dots by water in hydrogen-bonded matrices. Nat. Commun. 2018, 9 (1), 734,  DOI: 10.1038/s41467-018-03144-9
    Google Scholar
    11
    Induction of long-lived room temperature phosphorescence of carbon dots by water in hydrogen-bonded matrices
    Li Qijun; Zhou Ming; Yang Mingyang; Yang Qingfeng; Zhang Zhixun; Shi Jing
    Nature communications (2018), 9 (1), 734 ISSN:.
    Phosphorescence shows great potential for application in bioimaging and ion detection because of its long-lived luminescence and high signal-to-noise ratio, but establishing phosphorescence emission in aqueous environments remains a challenge. Herein, we present a general design strategy that effectively promotes phosphorescence by utilising water molecules to construct hydrogen-bonded networks between carbon dots (CDs) and cyanuric acid (CA). Interestingly, water molecules not only cause no phosphorescence quenching but also greatly enhance the phosphorescence emission. This enhancement behaviour can be explained by the fact that the highly ordered bound water on the CA particle surface can construct robust bridge-like hydrogen-bonded networks between the CDs and CA, which not only effectively rigidifies the C=O bonds of the CDs but also greatly enhances the rigidity of the entire system. In addition, the CD-CA suspension exhibits a high phosphorescence lifetime (687 ms) and is successfully applied in ion detection based on its visible phosphorescence.
  12. 12
    Xu, S.; Evans, R. E.; Liu, T.; Zhang, G.; Demas, J. N.; Trindle, C. O.; Fraser, C. L. Aromatic Difluoroboron β-Diketonate Complexes: Effects of π-Conjugation and Media on Optical Properties. Inorg. Chem. 2013, 52 (7), 3597– 3610,  DOI: 10.1021/ic300077g
    Google Scholar
    12
    Aromatic Difluoroboron β-Diketonate Complexes: Effects of π-Conjugation and Media on Optical Properties
    Xu, Songpan; Evans, Ruffin E.; Liu, Tiandong; Zhang, Guoqing; Demas, J. N.; Trindle, Carl O.; Fraser, Cassandra L.
    Inorganic Chemistry (2013), 52 (7), 3597-3610CODEN: INOCAJ; ISSN:0020-1669. (American Chemical Society)
    Arom. difluoroboron β-diketonate complexes (BF2bdks) are classic fluorescent mols. that were explored as photochem. reagents, two-photon dyes, and O sensors. To gain a better understanding of their emissive properties in both soln. and polymer matrixes, BF2bdks with varying arom. groups were synthesized and their photophys. properties were studied in both CH2Cl2 and poly(lactic acid) (PLA). Absorption spectra showed systematic variations that are well correlated with structural features, including the size of the aryl substituent and the presence of a para electron-donating methoxy substituent. Computational modeling of the absorption spectra with the TD-B3LYP/6-311+G(d)//B3LYP/6-31G(d) formulation of d. functional theory and a polarizable continuum model of CH2Cl2 solvent shows that all systems show intense π-π* 1-electron excitations, usually from one of the highest occupied MOs (HOMO - k, k = 0, 1, 2) to the LUMO. Emission properties are sensitive to the dye structure and medium. Based on spectroscopic and lifetime studies, BF2bdks exhibit comparable fluorescence properties in both solns. and polymers when the diketonate group is functionalized with smaller arom. ring systems such as benzene. For BF2bdks with larger arene ring systems, such as anthracene, emission from a strong intramol. charge-transfer (ICT) state was also noted in both soln. and in PLA. There are differences in relative intensities of peaks arising from π-π* and ICT excitations depending upon dye loading in PLA. Substituent effects were also obsd. Electron-donating methoxyl groups on the arom. rings lead to enhanced fluorescence quantum yields. For certain dyes, phosphorescence is detected at low temp. or under a N atm. in PLA matrixes.
  13. 13
    Daly, M. L.; Kerr, C.; DeRosa, C. A.; Fraser, C. L. Meta-Alkoxy-Substituted Difluoroboron Dibenzoylmethane Complexes as Environment-Sensitive Materials. ACS Appl. Mater. Interfaces 2017, 9 (37), 32008– 32017,  DOI: 10.1021/acsami.7b06910
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    13
    Meta-Alkoxy-Substituted Difluoroboron Dibenzoylmethane Complexes as Environment-Sensitive Materials
    Daly, Margaret L.; Kerr, Caroline; DeRosa, Christopher A.; Fraser, Cassandra L.
    ACS Applied Materials & Interfaces (2017), 9 (37), 32008-32017CODEN: AAMICK; ISSN:1944-8244. (American Chemical Society)
    The optical properties of meta-alkoxy-substituted difluoroboron dibenzoylmethane dyes were investigated in soln. and in the solid state. Meta-alkoxy substitution induced strong intramol. charge transfer (ICT) from the oxygen-donating substituent to the halide and boron acceptors in the excited state, as compared to the π-π* transition that is obsd. with para-alkoxy substitution. The optical properties of para- and meta-substituted alkoxy boron dyes were evaluated by calcns., in dil. soln., and in solid-state films. When embedded in amorphous matrixes (e.g., PLA, PMMA, PS, cholesterol), all dyes showed fluorescence (F) and phosphorescence (P) emission. In this report, we show that meta-substitution resulted in enhanced solvatochromism and an increased phosphorescence-to-fluorescence ratio in solid-state films compared to analogous para-substituted samples. With enhanced phosphorescence intensity via the heavy-atom effect, iodo-substituted dyes were further studied in PLA-PEG nanoparticles. Oxygen calibrations revealed stronger phosphorescence and a greater oxygen-sensing range for the meta- vs. para-alkoxy-substituted dyes, features that are important for oxygen-sensing materials design.
  14. 14
    Kwon, M. S.; Yu, Y.; Coburn, C.; Phillips, A. W.; Chung, K.; Shanker, A.; Jung, J.; Kim, G.; Pipe, K.; Forrest, S. R.; Youk, J. H.; Gierschner, J.; Kim, J. Suppressing molecular motions for enhanced room-temperature phosphorescence of metal-free organic materials. Nat. Commun. 2015, 6, 8947,  DOI: 10.1038/ncomms9947
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    14
    Suppressing molecular motions for enhanced room-temperature phosphorescence of metal-free organic materials
    Kwon, Min Sang; Yu, Youngchang; Coburn, Caleb; Phillips, Andrew W.; Chung, Kyeongwoon; Shanker, Apoorv; Jung, Jaehun; Kim, Gunho; Pipe, Kevin; Forrest, Stephen R.; Youk, Ji Ho; Gierschner, Johannes; Kim, Jinsang
    Nature Communications (2015), 6 (), 8947pp.CODEN: NCAOBW; ISSN:2041-1723. (Nature Publishing Group)
    Metal-free org. phosphorescent materials are attractive alternatives to the predominantly used organometallic phosphors but are generally dimmer and are relatively rare, as, without heavy-metal atoms, spin-orbit coupling is less efficient and phosphorescence usually cannot compete with radiationless relaxation processes. Here we present a general design rule and a method to effectively reduce radiationless transitions and hence greatly enhance phosphorescence efficiency of metal-free org. materials in a variety of amorphous polymer matrixes, based on the restriction of mol. motions in the proximity of embedded phosphors. Covalent crosslinking between phosphors and polymer matrixes via Diels-Alder click chem. is devised as a method. A sharp increase in phosphorescence quantum efficiency is obsd. in a variety of polymer matrixes with this method, which is ca. two to five times higher than that of phosphor-doped polymer systems having no such covalent linkage.
  15. 15
    Tao, S.; Lu, S.; Geng, Y.; Zhu, S.; Redfern, S. A. T.; Song, Y.; Feng, T.; Xu, W.; Yang, B. Design of Metal-Free Polymer Carbon Dots: A New Class of Room-Temperature Phosphorescent Materials. Angew. Chem., Int. Ed. 2018, 57 (9), 2393– 2398,  DOI: 10.1002/anie.201712662
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    15
    Design of Metal-Free Polymer Carbon Dots: A New Class of Room-Temperature Phosphorescent Materials
    Tao, Songyuan; Lu, Siyu; Geng, Yijia; Zhu, Shoujun; Redfern, Simon A. T.; Song, Yubin; Feng, Tanglue; Xu, Weiqing; Yang, Bai
    Angewandte Chemie, International Edition (2018), 57 (9), 2393-2398CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)
    Polymer carbon dots (PCDs) are proposed as a new class of room-temp. phosphorescence (RTP) materials. The abundant energy levels in PCDs increase the probability of intersystem crossing (ISC) and their covalently crosslinked framework structures greatly suppress the nonradiative transitions. The efficient methods allow the manuf. of PCDs with unique RTP properties in air without addnl. metal complexation or complicated matrix compn. They thus provide a route towards the rational design of metal-free RTP materials that may be synthesized easily. Furthermore, we find that RTP is assocd. with a crosslink-enhanced emission (CEE) effect, which provides further routes to design improved PCDs with diverse RTP performance. Our results show the potential of PCDs as a universal route to achieve effective metal-free RTP.
  16. 16
    Ogoshi, T.; Tsuchida, H.; Kakuta, T.; Yamagishi, T.-A.; Taema, A.; Ono, T.; Sugimoto, M.; Mizuno, M. Ultralong Room-Temperature Phosphorescence from Amorphous Polymer Poly(Styrene Sulfonic Acid) in Air in the Dry Solid State. Adv. Funct. Mater. 2018, 28 (16), 1707369,  DOI: 10.1002/adfm.201707369
    Google Scholar
    There is no corresponding record for this reference.
  17. 17
    Kanosue, K.; Ando, S. Polyimides with Heavy Halogens Exhibiting Room-Temperature Phosphorescence with Very Large Stokes Shifts. ACS Macro Lett. 2016, 5 (12), 1301– 1305,  DOI: 10.1021/acsmacrolett.6b00642
    Google Scholar
    17
    Polyimides with Heavy Halogens Exhibiting Room-Temperature Phosphorescence with Very Large Stokes Shifts
    Kanosue, Kenta; Ando, Shinji
    ACS Macro Letters (2016), 5 (12), 1301-1305CODEN: AMLCCD; ISSN:2161-1653. (American Chemical Society)
    Semiarom. polyimides (PIs) and imide compds. contg. heavy halogens (Br, I) in pyromellitic moieties were designed and synthesized to examine their photoluminescence properties. Solns. of imides and PI films exhibited reddish-color room-temp. phosphorescence (RTP) with very large Stokes shifts (ca. 10000 cm-1). In addn., the PI films showed small-Stokes-shifted fluorescence emissions at around 540 nm with absorption bands arising from aggregated PI chains at 400-500 nm. Enhanced phosphorescence obsd. for the PI films under vacuum indicates that the RTP lifetime is significantly influenced by the triplet-triplet energy transfer to atm. oxygen. These PIs with very-large-Stokes-shifted RTP are applicable as spectral conversion materials in displays, photovoltaic devices, and crop cultivators, as well as to oxygen/air sensors.
  18. 18
    Chen, H.; Ma, X.; Wu, S.; Tian, H. A Rapidly Self-Healing Supramolecular Polymer Hydrogel with Photostimulated Room-Temperature Phosphorescence Responsiveness. Angew. Chem., Int. Ed. 2014, 53 (51), 14149– 14152,  DOI: 10.1002/anie.201407402
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    18
    A Rapidly Self-Healing Supramolecular Polymer Hydrogel with Photostimulated Room-Temperature Phosphorescence Responsiveness
    Chen, Hui; Ma, Xiang; Wu, Shuaifan; Tian, He
    Angewandte Chemie, International Edition (2014), 53 (51), 14149-14152CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)
    Development of self-healing and photostimulated luminescent supramol. polymeric materials is important for artificial soft materials. A supramol. polymeric hydrogel is reported based on the host-guest recognition between a β-cyclodextrin (β-CD) host polymer (poly-β-CD) and an α-bromonaphthalene (α-BrNp) polymer (poly-BrNp) without any addnl. gelator, which can self-heal within only about one minute under ambient atm. without any additive. This supramol. polymer system can be excited to engender room-temp. phosphorescence (RTP) signals based on the fact that the inclusion of β-CD macrocycle with α-BrNp moiety is able to induce RTP emission (CD-RTP). The RTP signal can be adjusted reversibly by competitive complexation of β-CD with azobenzene moiety under specific irradn. by introducing another azobenzene guest polymer (poly-Azo).
  19. 19
    Zhang, Y.-F.; Wang, Y.-C.; Yu, X.-S.; Zhao, Y.; Ren, X.-K.; Zhao, J.-F.; Wang, J.; Jiang, X.-Q.; Chang, W.-Y.; Zheng, J.-F.; Yu, Z.-Q.; Yang, S.; Chen, E.-Q. Isophthalate-Based Room Temperature Phosphorescence: From Small Molecule to Side-Chain Jacketed Liquid Crystalline Polymer. Macromolecules 2019, 52 (6), 2495– 2503,  DOI: 10.1021/acs.macromol.9b00171
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    19
    Isophthalate-Based Room Temperature Phosphorescence: From Small Molecule to Side-Chain Jacketed Liquid Crystalline Polymer
    Zhang, Yan-Fang; Wang, Yue-Chao; Yu, Xiao-Song; Zhao, Yang; Ren, Xiang-Kui; Zhao, Jian-Feng; Wang, Jun; Jiang, Xu-Qiang; Chang, Wen-Ying; Zheng, Jun-Feng; Yu, Zhen-Qiang; Yang, Shuang; Chen, Er-Qiang
    Macromolecules (Washington, DC, United States) (2019), 52 (6), 2495-2503CODEN: MAMOBX; ISSN:0024-9297. (American Chemical Society)
    Isophthalate with the simple chem. structure is identified as an effective phosphor for room temp. phosphorescent (RTP) materials. With -Br, -CH3, and -CH=CH2 at the 5-position of the benzene ring of didecyl isophthalate, the three cryst. small mols. of DDIP-Br, DDIP-CH3, and DDIP-CH=CH2 demonstrate ultralong RTP with lifetime of 236, 650, and 184 ms, resp., although no specific interactions are recognized in the crystals. Radical polymn. of DDIP-CH=CH2 readily results in Poly-1, which is the first RTP liq. cryst. polymer. Direct attachment of isophthalate phosphor to every repeating unit of polyethylene backbone through a single carbon-carbon bond leads to a significant side-chain jacketing effect, greatly reducing the motion of phosphor moieties. Poly-1 renders a columnar LC phase constructed by parallel packing of the supramol. column that is composed of two Poly-1 chains. In the column, the isophthalate phosphor is confined in between the core of polymer backbones and the shell of decyl tails, and thus the nonradiative process is further suppressed. The materials design of Poly-1 can be widely applied for developing new RTP polymers.
  20. 20
    Yu, Y.; Kwon, M. S.; Jung, J.; Zeng, Y.; Kim, M.; Chung, K.; Gierschner, J.; Youk, J. H.; Borisov, S. M.; Kim, J. Room-Temperature-Phosphorescence-Based Dissolved Oxygen Detection by Core-Shell Polymer Nanoparticles Containing Metal-Free Organic Phosphors. Angew. Chem., Int. Ed. 2017, 56 (51), 16207– 16211,  DOI: 10.1002/anie.201708606
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    20
    Room-Temperature-Phosphorescence-Based Dissolved Oxygen Detection by Core-Shell Polymer Nanoparticles Containing Metal-Free Organic Phosphors
    Yu, Youngchang; Kwon, Min Sang; Jung, Jaehun; Zeng, Yingying; Kim, Mounggon; Chung, Kyeongwoon; Gierschner, Johannes; Youk, Ji Ho; Borisov, Sergey M.; Kim, Jinsang
    Angewandte Chemie, International Edition (2017), 56 (51), 16207-16211CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)
    The highly sensitive optical detection of O including dissolved O (DO) is of great interest in various applications. We devised a novel room-temp.-phosphorescence (RTP)-based O detection platform by constructing core-shell nanoparticles with water-sol. polymethyloxazoline shells and O-permeable polystyrene cores crosslinked with metal-free purely org. phosphors. The resulting nanoparticles show a very high sensitivity for DO with a limit of detection (LOD) of 60nM and can be readily used for O quantification in aq. environments as well as the gaseous phase.
  21. 21
    Wang, X.-F.; Xiao, H.; Chen, P.-Z.; Yang, Q.-Z.; Chen, B.; Tung, C.-H.; Chen, Y.-Z.; Wu, L.-Z. Pure Organic Room Temperature Phosphorescence from Excited Dimers in Self-Assembled Nanoparticles under Visible and Near-Infrared Irradiation in Water. J. Am. Chem. Soc. 2019, 141 (12), 5045– 5050,  DOI: 10.1021/jacs.9b00859
    Google Scholar
    21
    Pure Organic Room Temperature Phosphorescence from Excited Dimers in Self-Assembled Nanoparticles under Visible and Near-Infrared Irradiation in Water
    Wang, Xiao-Fang; Xiao, Hongyan; Chen, Peng-Zhong; Yang, Qing-Zheng; Chen, Bin; Tung, Chen-Ho; Chen, Yu-Zhe; Wu, Li-Zhu
    Journal of the American Chemical Society (2019), 141 (12), 5045-5050CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)
    Pure org. room temp. phosphorescence (RTP) has unique advantages and various potential applications. However, it is challengeable to achieve org. RTP under visible and near-IR (NIR)-light excitation, esp. in aq. soln. Herein the authors assemble difluoroboron β-diketonate compds. to form org. nanoparticles (NPs) in water. The resulting NPs are able to show efficient RTP, effective uptake, and bright imaging of HeLa cells under both visible- and NIR-light excitation. More strikingly, spectroscopic study, single-crystal x-ray diffraction, and DFT calcn. reveal that the efficient RTP in org. NPs is originated from dimers in their excited states. The multiple interactions and intermol. charge transfer in the dimer structures are of significance in promoting the prodn. of dimer triplet excited states and suppressing the nonradiative decays to boost the RTP under visible- and NIR-light irradn. in water.
  22. 22
    Wang, D.; Wang, X.; Xu, C.; Ma, X. A novel metal-free amorphous room-temperature phosphorescent polymer without conjugation. Sci. China: Chem. 2019, 62 (4), 430– 433,  DOI: 10.1007/s11426-018-9383-2
    Google Scholar
    22
    A novel metal-free amorphous room-temperature phosphorescent polymer without conjugation
    Wang, Disen; Wang, Xi; Xu, Chao; Ma, Xiang
    Science China: Chemistry (2019), 62 (4), 430-433CODEN: SCCCCS; ISSN:1869-1870. (Science China Press)
    Room-temp. phosphorescence (RTP) has attracted much attention due to its potential applications in the fields of biol. imaging, chem. sensors and so forth. Particularly, amorphous metal-free RTP materials show special advantages of low cost and good processability. In addn., non-conjugated polymers have seldom been reported as phosphorescent materials. In this work, a novel non-conjugated amorphous metal-free copolymer composed of brominated olefins and acrylamide was prepd. in a facile way, which could engender blue-purple RTP emission. Polymers with different kinds of brominated olefins and different ratios of two monomers have been investigated with the purpose of researching the compn./property relationship that may affect the RTP properties. This unique phenomenon could be due to the clustering of carbonyl and amino units caused mol. interaction, and the heavy-atom effect enhanced intersystem crossing. Meantime, the hydrogen bonding in the system enhanced the conformation rigidification to reduce the non-radiative decay. This work provided a delicate way to construct non-conjugated metal-free RTP materials and supplied a new insight into the development of RTP materials.
  23. 23
    Zhang, T.; Chen, H.; Ma, X.; Tian, H. Amorphous 2-Bromocarbazole Copolymers with Efficient Room-Temperature Phosphorescent Emission and Applications as Encryption Ink. Ind. Eng. Chem. Res. 2017, 56 (11), 3123– 3128,  DOI: 10.1021/acs.iecr.7b00149
    Google Scholar
    23
    Amorphous 2-Bromocarbazole Copolymers with Efficient Room-Temperature Phosphorescent Emission and Applications as Encryption Ink
    Zhang, Ting; Chen, Hui; Ma, Xiang; Tian, He
    Industrial & Engineering Chemistry Research (2017), 56 (11), 3123-3128CODEN: IECRED; ISSN:0888-5885. (American Chemical Society)
    The development of metal-free org. room-temp. phosphorescent (RTP) materials is promising but challenging, because spin-orbit coupling is less efficient without heavy metals such as platinum and palladium. Here, we present a novel amorphous copolymer composed of 2-bromocarbazole phosphor and acrylamide on its side chains, which can engender blue-purple phosphorescence emission with high quantum yield at room temp. The polymer matrixes of acrylamide and the hydrogen bonding in the polymeric chain system can effectively help to inhibit nonradiative transition process and, hence, strengthen the phosphorescent emission. The molar ratio of the 2-bromocarbazole phosphor and acrylamide remarkably influences the RTP emission intensities and quantum yields of the polymers. The high amt. of phosphor will weaken the rigidity of the polymers and the shielding effect from oxygen, thus leading to a decrease in their RTP emission, while a low concn. of the phosphor will also weaken their RTP emission intensity. Furthermore, RTP intensity of the amorphous polymer is responsive to humidity, because the hydrogen bonding in the polymeric chain system can be broken by water, which makes it applicable in the area of encryption.
  24. 24
    Zhao, Q.; Li, F.; Huang, C. Phosphorescent chemosensors based on heavy-metal complexes. Chem. Soc. Rev. 2010, 39 (8), 3007– 3030,  DOI: 10.1039/b915340c
    Google Scholar
    24
    Phosphorescent chemosensors based on heavy-metal complexes
    Zhao, Qiang; Li, Fuyou; Huang, Chunhui
    Chemical Society Reviews (2010), 39 (8), 3007-3030CODEN: CSRVBR; ISSN:0306-0012. (Royal Society of Chemistry)
    A review. Recently, the use of phosphorescent heavy-metal complexes as chemosensors has attracted increasing interest due to their advantageous photophys. properties. This crit. review focuses on the design principles and the recent development of phosphorescent chemosensors for metal cations, anions, pH, oxygen, volatile org. compds. and biomols. based on some heavy-metal complexes (such as Pt(II)-, Ru(II)-, Re(I)-, Ir(III)-, Cu(I)-, Au(I)- and Os(II)-based complexes), in which the variation in phosphorescence signals induced by the interaction between heavy-metal complexes and analytes is used (217 refs.).
  25. 25
    Ravotto, L.; Ceroni, P. Aggregation induced phosphorescence of metal complexes: From principles to applications. Coord. Chem. Rev. 2017, 346, 62– 76,  DOI: 10.1016/j.ccr.2017.01.006
    Google Scholar
    25
    Aggregation induced phosphorescence of metal complexes: From principles to applications
    Ravotto, Luca; Ceroni, Paola
    Coordination Chemistry Reviews (2017), 346 (), 62-76CODEN: CCHRAM; ISSN:0010-8545. (Elsevier B.V.)
    Metal complexes are the prototypes of phosphorescent materials, widely used in a range of optoelectronic and sensing applications. This review reports the most recent and tutorial results in the area of aggregation induced phosphorescence (AIP) of metal complexes, i.e. mols. that are weakly or non-phosphorescent in deaerated fluid soln. and whose room temp. phosphorescence is switched on upon aggregation. The examples are divided into two main classes according to the AIP mechanism: (i) rigidification that causes a restriction of intramol. motions as well as of structural distortion of the phosphorescent excited state and (ii) metallophilic interaction that brings about new electronic transitions compared to the isolated chromophores. The last section is devoted to a special class of mols. and supramol. systems, in which metal complexation turns on phosphorescence of nearby org. chromophores, so that the metal complex is not directly involved in the phosphorescence process.
  26. 26
    Yang, Y.; Wang, K.-Z.; Yan, D. Ultralong Persistent Room Temperature Phosphorescence of Metal Coordination Polymers Exhibiting Reversible pH-Responsive Emission. ACS Appl. Mater. Interfaces 2016, 8 (24), 15489– 15496,  DOI: 10.1021/acsami.6b03956
    Google Scholar
    26
    Ultralong Persistent Room Temperature Phosphorescence of Metal Coordination Polymers Exhibiting Reversible pH-Responsive Emission
    Yang, Yongsheng; Wang, Ke-Zhi; Yan, Dongpeng
    ACS Applied Materials & Interfaces (2016), 8 (24), 15489-15496CODEN: AAMICK; ISSN:1944-8244. (American Chemical Society)
    Ultra-long-persistent room temp. phosphorescence (RTP) materials have attracted much attention and present various applications in illumination, displays, and the bioimaging field; the persistent RTP is generally from the inorg. phosphor materials to date. The metal coordination polymers (CPs) could be new types of emerging long-lived RTP materials for potential sensor applications. First, 2 kinds of Cd-based CPs, Cd(m-BDC)(H2O) (1) and Cd(m-BDC)(BIM) (2) (m-BDC = 1,3-benzenedicarboxylic acid; BIM = benzimidazole), were obtained through a hydrothermal process, and the samples exhibit 2-dimensional layered structures, which are stabilized by interlayer C-H···π interaction and π···π interaction, resp. The CPs show unexpected 2nd-time-scale ultra-long-persistent RTP after the removal of UV excitation, and this persistent emission can be detected easily on a time scale of 0-10 s. The CPs also feature a tunable luminescence decay lifetime by adjusting their coordination situation and packing fashion of ligands. Theor. calcn. further indicates that the introduction of the 2nd ligand could highly influence the electronic structure and intermol. electron transfer toward tailoring the RTP of the CP materials. CP 2 exhibits well-defined pH- and temp.-dependent phosphorescence responses. Therefore, this work provides a facile way to develop new type of CPs with steady-state and dynamic tuning of the RTP properties from both exptl. and theor. perspectives, which have potential applications in the areas of displays, pH/temp. sensors, and phosphorescence logic gates. On account of suitable incorporation of inorg. and org. building blocks, it can be expected that the ultra-long-persistent RTP CPs can be extended to other similar systems due to the highly tunable structures and facile synthesis routes.
  27. 27
    Yan, Q.; Fan, Y.; Zhao, D. Unusual Temperature-Dependent Photophysics of Oligofluorene-Substituted Tris-Cyclometalated Iridium Complexes. Macromolecules 2012, 45 (1), 133– 141,  DOI: 10.1021/ma2024123
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    Unusual Temperature-Dependent Photophysics of Oligofluorene-Substituted Tris-Cyclometalated Iridium Complexes
    Yan, Qifan; Fan, Yuanpeng; Zhao, Dahui
    Macromolecules (Washington, DC, United States) (2012), 45 (1), 133-141CODEN: MAMOBX; ISSN:0024-9297. (American Chemical Society)
    The photophys. properties of a series of tris-cyclometalated Ir(III) complexes bearing oligofluorene-substituted 2-phenylpyridine (ppy) and/or 1-phenylisoquinoline (piq) ligands were studied at both room temp. and 77 K, for delineating the oligomer-substitution effects on the photophysics in such metal-complex-contg. conjugated oligomers/polymers. Unique temp. dependence was obsd. with the triplet excited-state lifetime of the studied oligomers. Mols. having one of the three ppy ligands substituted with an oligofluorenyl group at varied positions exhibited two distinct types of phosphorescing behaviors. When the oligofluorene group was coupled to ppy in a conjugative fashion (i.e., at 5- or 4'- position), the complexes appeared to emit from a 3MLCT-dominated state perturbed by LC transition, as evidenced by the relatively short lifetimes of phosphorescence as well as hypsochromic shift upon lowering the temp. Surprisingly, even shorter triplet lifetimes were detected at 77 K for such oligomers. When the oligofluorenyl was tethered to the Ph ring of ppy meta to pyridine, emission properties were consistent with a 3LC-dominated state, mixed with a certain MLCT component. Uniquely, for these oligomers an evident bathochromic shift of emission with a significantly retarded radiative decay rate was obsd. at 77 K. Furthermore, when a piq ligand was incorporated, red phosphorescence characteristic of Ir-piq-based 3MLCT transition emerged, disregarding the substation position of the oligofluorene. All these different photophys. behaviors, particularly their unique temp. dependence, were explained by considering an energy transfer process between different triplet states, with dominant MLCT and LC characteristics. In complexes having all ppy-derived ligands, these two states were of similar but different energy. While one played a more important role than the other, both were contributing to the phosphorescence emission. The temp. dependence of the photophysics reflected the equil. shifting process. When the 3MLCT-dominated state was lower in energy, faster radiative decay and shorter lifetimes were manifested upon lowering the temp., as a result of more favored 3MLCT-dominated state. Whereas if the 3LC-dominated state was more stable, slower radiative decay emerged at decreased temp. due to further a reduced MLCT contribution. The bathochromic shift was also a result of equil. shifting to the state of lower energy. When the piq ligand was engaged, the emission was governed by the 3MLCT state of the Ir-piq moiety, which had much lower energy compared to the triplet states localized in oligofluorenyl ppy. DFT calcns. substantiated the above hypothesis by identifying sep. MOs possessing mixed but imbalanced MLCT and LC components.
  28. 28
    Schubert, D. M. Boron: inorganic chemistry. Encyclopedia of Inorganic and Bioinorganic Chemistry 2015, 1– 28,  DOI: 10.1002/9781119951438.eibc0024.pub2
    Google Scholar
    28
    Boron: inorganic chemistry
    Schubert, David M.
    Encyclopedia of Inorganic and Bioinorganic Chemistry (2015), (), 1-28CODEN: 69UGQZ ISSN:. (John Wiley & Sons Ltd.)
    There is no expanded citation for this reference.
  29. 29
    Wu, Q.; Xiong, H.; Peng, Y.; Yang, Y.; Kang, J.; Huang, G.; Ren, X.; Wu, J. Highly Stretchable and Self-Healing “Solid-Liquid” Elastomer with Strain-Rate Sensing Capability. ACS Appl. Mater. Interfaces 2019, 11 (21), 19534– 19540,  DOI: 10.1021/acsami.9b05230
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    29
    Highly Stretchable and Self-Healing "Solid-Liquid" Elastomer with Strain-Rate Sensing Capability
    Wu, Qi; Xiong, Hui; Peng, Yan; Yang, Yi; Kang, Jian; Huang, Guangsu; Ren, Xiancheng; Wu, Jinrong
    ACS Applied Materials & Interfaces (2019), 11 (21), 19534-19540CODEN: AAMICK; ISSN:1944-8244. (American Chemical Society)
    To mimic the velocity-sensitive ability of the human skin, we fabricate a class of "solid-liq." elastomers (SLEs) by interpenetrating polyborosiloxane (PBS) with polydimethylsiloxane (PDMS). PBS forms a dynamic network through boron/oxygen dative bonds, while PDMS is covalently crosslinked to form a permanent network. The permanent network affords a scaffold for the dynamic network, endowing SLEs with high elasticity and structural stability, thereby overcoming the inherent drawbacks such as fluidity and irreversible deformation of conventional solid-liq. materials. Meanwhile, the dissocn. and assocn. of the dynamic network is time-dependent. Thus, the modulus of SLEs varies with strain rates, and if the SLEs contain carbon nanotubes, their elec. cond. is also responsive to strain rates. This property can be utilized to fabricate skin-like sensors with the ability to distinguish different contact velocities. Moreover, the dynamic network can dissipate energy and be repaired, leading to the high stretchability and self-healing performance of SLEs.
  30. 30
    Wang, M.; Nudelman, F.; Matthes, R. R.; Shaver, M. P. Frustrated Lewis Pair Polymers as Responsive Self-Healing Gels. J. Am. Chem. Soc. 2017, 139 (40), 14232– 14236,  DOI: 10.1021/jacs.7b07725
    Google Scholar
    30
    Frustrated Lewis Pair Polymers as Responsive Self-Healing Gels
    Wang, Meng; Nudelman, Fabio; Matthes, Rebecca R.; Shaver, Michael P.
    Journal of the American Chemical Society (2017), 139 (40), 14232-14236CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)
    Steric bulk prevents the formation of strong bonds between Lewis acids and bases in frustrated Lewis pairs (FLPs), where latent reactivity makes these reagents transformative in small mol. activations and metal-free catalysis. However, their use as a platform for developing materials chem. is unexplored. Here we report a fully macromol. FLP, built from linear copolymers that contg. either a sterically encumbered Lewis base or Lewis acid as a pendant functional group. The target functional copolymers were prepd. by a controlled radical copolymn. of styrene with designer boron or phosphorus contg. monomers. Mixts. of the B- and P-functionalized polystyrenes do not react, with the steric bulk of the functional monomers preventing the favorable Lewis acid base interaction. Addn. of a small mol. (di-Et azodicarboxylate) promotes rapid network formation, crosslinking the reactive polymer chains. The resulting gel is dynamic, can self-heal, is heat responsive, and can be reshaped by postgelation processing.
  31. 31
    Icli, B.; Sheepwash, E.; Riis-Johannessen, T.; Schenk, K.; Filinchuk, Y.; Scopelliti, R.; Severin, K. Dative boron-nitrogen bonds in structural supramolecular chemistry: multicomponent assembly of prismatic organic cages. Chem. Sci. 2011, 2 (9), 1719– 1721,  DOI: 10.1039/c1sc00320h
    Google Scholar
    31
    Dative boron-nitrogen bonds in structural supramolecular chemistry: multicomponent assembly of prismatic organic cages
    Icli, Burcak; Sheepwash, Erin; Riis-Johannessen, Thomas; Schenk, Kurt; Filinchuk, Yaroslav; Scopelliti, Rosario; Severin, Kay
    Chemical Science (2011), 2 (9), 1719-1721CODEN: CSHCCN; ISSN:2041-6520. (Royal Society of Chemistry)
    The multicomponent reaction of diboronic acids with a catechol and a tripyridyl linker results in the formation trigonal prismatic cages. The cages feature 6 dative B-N bonds as structure-directing elements. The size of the cages can be varied by changing the diboronic acid building block. The cages are able to encapsulate polyarom. mols. such as triphenylene or coronene.
  32. 32
    Beuerle, F.; Gole, B. Covalent Organic Frameworks and Cage Compounds: Design and Applications of Polymeric and Discrete Organic Scaffolds. Angew. Chem., Int. Ed. 2018, 57 (18), 4850– 4878,  DOI: 10.1002/anie.201710190
    Google Scholar
    32
    Covalent Organic Frameworks and Cage Compounds: Design and Applications of Polymeric and Discrete Organic Scaffolds
    Beuerle, Florian; Gole, Bappaditya
    Angewandte Chemie, International Edition (2018), 57 (18), 4850-4878CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)
    A review. Porous org. materials are an emerging class of functional nanostructures with unprecedented properties. Dynamic covalent assembly of small org. building blocks under thermodn. control is utilized for the intriguingly simple formation of complex mol. architectures in one-pot procedures. In this Review, we aim to analyze the basic design principles that govern the formation of either covalent org. frameworks as cryst. porous polymers or covalent org. cage compds. as shape-persistent mol. objects. Common synthetic procedures and characterization techniques will be discussed and more advanced strategies such as postsynthetic modification or self-sorting. When appropriate, comparisons are drawn between polymeric frameworks and discrete org. cages in terms of their underlying properties. Furthermore, we highlight the potential of these materials for applications ranging from gas storage to catalysis and org. electronics.
  33. 33
    Sheepwash, E.; Krampl, V.; Scopelliti, R.; Sereda, O.; Neels, A.; Severin, K. Molecular Networks Based on Dative Boron-Nitrogen Bonds. Angew. Chem., Int. Ed. 2011, 50 (13), 3034– 3037,  DOI: 10.1002/anie.201007225
    Google Scholar
    33
    Molecular Networks Based on Dative Boron-Nitrogen Bonds
    Sheepwash, Erin; Krampl, Vincent; Scopelliti, Rosario; Sereda, Olha; Neels, Antonia; Severin, Kay
    Angewandte Chemie, International Edition (2011), 50 (13), 3034-3037, S3034/1-S3034/12CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)
    Cryst. polymers are prepd. by reaction of I (R = single bond), 4-tert-butylcatechol (II), and 4,4'-bipyridine (III) or 1,2-bis(4-pyridyl)ethylene 3 h in 2:1 Ph-THF mixt. at reflux, and gels are prepd. by reaction of I (R = p-C6H4) (IV), II, and III in PhMe. Alternatively, a gel was prepd. by reaction of IV with II, and reaction of the intermediate triboronate ester with III,. NMR showed that the gel formed at about 60° and a rupture of BN bonds occurred at 60-90°. The gel-sol transition was accompanied with a loss of orange color. The crystal structure was discussed for of the cryst. polymers.
  34. 34
    Stephens, A. J.; Scopelliti, R.; Tirani, F. F.; Solari, E.; Severin, K. Crystalline Polymers Based on Dative Boron-Nitrogen Bonds and the Quest for Porosity. ACS Mater. Lett. 2019, 1 (1), 3– 7,  DOI: 10.1021/acsmaterialslett.9b00054
    Google Scholar
    34
    Crystalline Polymers Based on Dative Boron-Nitrogen Bonds and the Quest for Porosity
    Stephens, Alexander J.; Scopelliti, Rosario; Tirani, Farzaneh Fadaei; Solari, Euro; Severin, Kay
    ACS Materials Letters (2019), 1 (1), 3-7CODEN: AMLCEF; ISSN:2639-4979. (American Chemical Society)
    Cryst. networks based on dative boron-nitrogen bonds were obtained by combining polytopic N-donor ligands with polyboronic esters. The use of a tetrahedral boronate ester gave rise to a sheet structure, whereas either a linear polymer or a diamond-like network was obsd. for a tetrahedral N-donor ligand. The intrinsic flexibility of B←N linkages favors tight intermol. packing and interpenetration in the cryst. state. Amorphous B←N networks, however, possess porosity with BET surface areas of up to ∼300 m2 g-1. These materials display processability in org. solvents, and hydrolytic damage can be repaired by simple heating-cooling cycles.
  35. 35
    Zhang, G.; Chen, J.; Payne, S. J.; Kooi, S. E.; Demas, J. N.; Fraser, C. L. Multi-Emissive Difluoroboron Dibenzoylmethane Polylactide Exhibiting Intense Fluorescence and Oxygen-Sensitive Room-Temperature Phosphorescence. J. Am. Chem. Soc. 2007, 129 (29), 8942– 8943,  DOI: 10.1021/ja0720255
    Google Scholar
    35
    Multi-Emissive Difluoroboron Dibenzoylmethane Polylactide Exhibiting Intense Fluorescence and Oxygen-Sensitive Room-Temperature Phosphorescence
    Zhang, Guoqing; Chen, Jianbin; Payne, Sarah J.; Kooi, Steven E.; Demas, J. N.; Fraser, Cassandra L.
    Journal of the American Chemical Society (2007), 129 (29), 8942-8943CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)
    Boron difluoride compds. are light emitting materials with impressive optical properties. Though their strong one- and two-photon absorption and intense fluorescence are well-known and exploited in mol. probes, lasers, and photosensitizers, phosphorescence, in contrast, is typically obsd. only at low temps. Here, the authors report that unusual room-temp. phosphorescence is achieved by combining a classic boron dye, difluoroboron dibenzoylmethane, BF2dbm, with poly(lactic acid) (PLA), a common biopolymer, resulting in a highly sensitive single-component oxygen sensor. Fluorescence quantum yields are enhanced, and temp.-sensitive delayed fluorescence is also obsd. Multi-emissive BF2dbmPLA biomaterials show great promise as multifunctional mol. probes and sensors.
  36. 36
    Zhang, G.; Evans, R. E.; Campbell, K. A.; Fraser, C. L. Role of Boron in the Polymer Chemistry and Photophysical Properties of Difluoroboron-Dibenzoylmethane Polylactide. Macromolecules 2009, 42 (22), 8627– 8633,  DOI: 10.1021/ma9019043
    Google Scholar
    36
    Role of Boron in the Polymer Chemistry and Photophysical Properties of Difluoroboron-Dibenzoylmethane Polylactide
    Zhang, Guoqing; Evans, Ruffin E.; Campbell, Kirsti A.; Fraser, Cassandra L.
    Macromolecules (Washington, DC, United States) (2009), 42 (22), 8627-8633CODEN: MAMOBX; ISSN:0024-9297. (American Chemical Society)
    Difluoroboron β-diketonate-polymer conjugates have remarkable solid-state luminescent properties that are useful in a variety of fields including multiphoton microscopy, cell biol., and tumor hypoxia imaging. Despite the successful applications of these systems, the role of B in these polymeric materials has not been thoroughly studied; a boron-free model system with dibenzoylmethane chromophores in poly(lactic acid) (PLA) was studied, for comparison. The hydroxyl-functionalized arom. diketone dibenzoylmethane (dbmOH), is weakly fluorescent in the solid state and nonfluorescent in soln. while its difluoroboron complex (BF2dbmOH) is highly emissive in both states. Using dbmOH and BF2dbmOH as initiators, well-defined end-functionalized polylactides, dbmPLA and BF2dbmPLA, were obtained via tin-catalyzed controlled ring-opening polymn. Boronation of the dbmOH initiator affects the polymn. kinetics and the photophys. properties of the resulting BF2dbmPLA material. Both dbmPLA and BF2dbmPLA are dual emissive in the solid state, exhibiting both fluorescence and room-temp. phosphorescence (RTP), whereas only BF2dbmPLA is luminescent in soln. These results suggest that B plays two roles: (1) as a protecting group in polymn. and (2) as emission enhancer. The presence of dual emission for both polymers indicates that it may be the diketone core structure rather than the difluoroboron that is essential for RTP in a rigid PLA matrix.
  37. 37
    Shoji, Y.; Ikabata, Y.; Wang, Q.; Nemoto, D.; Sakamoto, A.; Tanaka, N.; Seino, J.; Nakai, H.; Fukushima, T. Unveiling a New Aspect of Simple Arylboronic Esters: Long-Lived Room-Temperature Phosphorescence from Heavy-Atom-Free Molecules. J. Am. Chem. Soc. 2017, 139 (7), 2728– 2733,  DOI: 10.1021/jacs.6b11984
    Google Scholar
    37
    Unveiling a New Aspect of Simple Arylboronic Esters: Long-Lived Room-Temperature Phosphorescence from Heavy-Atom-Free Molecules
    Shoji, Yoshiaki; Ikabata, Yasuhiro; Wang, Qi; Nemoto, Daisuke; Sakamoto, Atsushi; Tanaka, Naoki; Seino, Junji; Nakai, Hiromi; Fukushima, Takanori
    Journal of the American Chemical Society (2017), 139 (7), 2728-2733CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)
    Arylboronic esters can be used as versatile reagents in org. synthesis, as represented by Suzuki-Miyaura cross-coupling. Here we report a serendipitous finding that simple arylboronic esters are phosphorescent in the solid state at room temp. with a lifetime on the order of several seconds. The phosphorescence properties of arylboronic esters are remarkable in light of the general notion that phosphorescent org. mols. require heavy atoms and/or carbonyl groups for the efficient generation of a triplet excited state. Theor. calcns. on phenylboronic acid pinacol ester indicated that this mol. undergoes an out-of-plane distortion at the (pinacol)B-Cipso moiety in the T1 excited state, which is responsible for its phosphorescence. A compd. survey with 19 arylboron compds. suggested that the phosphorescence properties might be detd. by solid-state mol. packing rather than by the patterns and nos. of boron substituents on the aryl units. The present finding may update the general notion of phosphorescent org. mols.
  38. 38
    Kuno, S.; Kanamori, T.; Yijing, Z.; Ohtani, H.; Yuasa, H. Long Persistent Phosphorescence of Crystalline Phenylboronic Acid Derivatives: Photophysics and a Mechanistic Study. ChemPhotoChem. 2017, 1 (3), 102– 106,  DOI: 10.1002/cptc.201600031
    Google Scholar
    38
    Long Persistent Phosphorescence of Crystalline Phenylboronic Acid Derivatives: Photophysics and a Mechanistic Study
    Kuno, Shinichi; Kanamori, Takashi; Yijing, Zhao; Ohtani, Hiroyuki; Yuasa, Hideya
    ChemPhotoChem (2017), 1 (3), 102-106CODEN: CHEMYH ISSN:. (Wiley-VCH Verlag GmbH & Co. KGaA)
    Room-temp. phosphorescence (RTP) of cryst. isophthalic acid (IPA) through hyperfine-coupling-driven (HFC-driven) intersystem crossing in charge-transfer (CT) complexes has been discovered recently, giving rise to a new design method for phosphorescence materials and photosensitizers. In this study, we found that cryst. phenylboronic acid (PB) derivs. also demonstrated RTP, as recorded for IPA. Magnetic-field and spin-isotope effects on the emission strength intensities of PBs were typical of HFC-driven phosphorescence. p-Halogenated PB esters exhibited a heavy-atom effect with a shortened emission lifetime as expected from the study of IPA. Unlike IPA, the esters of PBs also showed RTP, which facilitates a study of the structure/photophys. property relationships by exchanging ester head groups. We then addressed a question: do PB esters with a bulky head group prohibit CT formation and thus phosphorescence. As a result, a bulky PB ester with large intermol. distances in its cryst. form showed neither CT absorptions nor phosphorescence, confirming the significance of CT formation in the HFC mechanism.
  39. 39
    Chai, Z.; Wang, C.; Wang, J.; Liu, F.; Xie, Y.; Zhang, Y.-Z.; Li, J.-R.; Li, Q.; Li, Z. Abnormal room temperature phosphorescence of purely organic boron-containing compounds: the relationship between the emissive behaviorand the molecular packing, and the potential related applications. Chem. Sci. 2017, 8 (12), 8336– 8344,  DOI: 10.1039/C7SC04098A
    Google Scholar
    39
    Abnormal room temperature phosphorescence of purely organic boron-containing compounds: the relationship between the emissive behavior and the molecular packing, and the potential related applications
    Chai, Zhaofei; Wang, Can; Wang, Jinfeng; Liu, Fan; Xie, Yujun; Zhang, Yong-Zheng; Li, Jian-Rong; Li, Qianqian; Li, Zhen
    Chemical Science (2017), 8 (12), 8336-8344CODEN: CSHCCN; ISSN:2041-6520. (Royal Society of Chemistry)
    Purely org. materials with the characteristic of room-temp. phosphorescence (RTP) under ambient conditions demonstrate potential benefits in advanced optoelectronic applications. Exploration of versatile and efficient RTP compds. with low prices is full of challenges due to the slow intersystem crossing process and ultrafast deactivation of the active excited states of org. compds. Here, a series of boron-contg. phosphors were found to present RTP with long-lived lifetimes. Among these com. available and cheap compds., (4-methoxyphenyl)boronic acid (PBA-MeO) exhibits long-lived RTP, with a lifetime of 2.24 s, which is among the longest lifetimes of single-component small mols. Our extensive expts. illustrate that both a rigid conformation and expanded conjugation induced by mol. alignment contribute to the persistent RTP. Because of strong intermol. interactions via hydrogen bonds, these arylboronic acids easily form crystals and are quite appropriate for anti-forgery materials. Subsequently, we develop a precise, speedy and convenient inkjet printing technol. for the fabrication of optoelectronic displays. Furthermore, PBA-MeO is used as an additive to feed Bombyx mori silkworms and shows low toxicity over inorg. materials. Our findings may pave a new way for the development of RTP phosphors and promote their use in practical applications.
  40. 40
    Zhang, K.; Sun, Q.; Tang, L.; Wang, Y.; Fan, X.; Liu, L.; Xue, S.; Yang, W. Cyclic boron esterification: screening organic room temperature phosphorescent and mechanoluminescent materials. J. Mater. Chem. C 2018, 6 (32), 8733– 8737,  DOI: 10.1039/C8TC02938E
    Google Scholar
    40
    Cyclic boron esterification: screening organic room temperature phosphorescent and mechanoluminescent materials
    Zhang, Kai; Sun, Qikun; Tang, Liangliang; Wang, Yanhui; Fan, Xiaojing; Liu, Linxi; Xue, Shanfeng; Yang, Wenjun
    Journal of Materials Chemistry C: Materials for Optical and Electronic Devices (2018), 6 (32), 8733-8737CODEN: JMCCCX; ISSN:2050-7534. (Royal Society of Chemistry)
    Aryl boronic acids are a broad class of org. intermediates. Their cyclic-esterification with appropriate dihydric alcs. is a simple and effective approach for screening org. room-temp. phosphorescent (RTP) and mechanoluminescent (ML) materials. Non RTP and ML active 4-(carbazol-9-yl)phenylboronic acid can be made into long-lived RTP emitters with lifetimes of 264 and 430 ms and a bright ML dye with blue emission by cyclic-esterification with 1,3-propanediol, 2,2-dimethyl-1,3-propanediol, and glycol, resp. Systematic single crystal anal. and quantum chem. calcns. indicate that cyclic borates dominate the mol. packing structures and intermol. interactions, which is responsible for the different optical properties.
  41. 41
    Li, M.; Ling, K.; Shi, H.; Gan, N.; Song, L.; Cai, S.; Cheng, Z.; Gu, L.; Wang, X.; Ma, C.; Gu, M.; Wu, Q.; Bian, L.; Liu, M.; An, Z.; Ma, H.; Huang, W. Prolonging Ultralong Organic Phosphorescence Lifetime to 2.5 s through Confining Rotation in Molecular Rotor. Adv. Opt. Mater. 2019, 7 (10), 1800820,  DOI: 10.1002/adom.201800820
    Google Scholar
    There is no corresponding record for this reference.
  42. 42
    Nakahata, M.; Mori, S.; Takashima, Y.; Hashidzume, A.; Yamaguchi, H.; Harada, A. pH- and Sugar-Responsive Gel Assemblies Based on Boronate-Catechol Interactions. ACS Macro Lett. 2014, 3 (4), 337– 340,  DOI: 10.1021/mz500035w
    Google Scholar
    42
    pH- and Sugar-Responsive Gel Assemblies Based on Boronate-Catechol Interactions
    Nakahata, Masaki; Mori, Shoko; Takashima, Yoshinori; Hashidzume, Akihito; Yamaguchi, Hiroyasu; Harada, Akira
    ACS Macro Letters (2014), 3 (4), 337-340CODEN: AMLCCD; ISSN:2161-1653. (American Chemical Society)
    The interaction between poly(acrylamide) gels carrying phenylboronic acid (PB gel) and catechol moieties (CAT gel) resp. is studied. The PB gel forms an assembly with the CAT gel on a macroscopic scale in basic aq. media. The adhesion strength is estd. by stress-strain measurements. The assembly and disassembly of the gels are reversibly switched by varying the pH of the medium. The adhesion strength is tunable by competitive monosaccharide mols. in accordance with the assocn. const. with PB moieties.
  43. 43
    Smith, M. K.; Northrop, B. H. Vibrational Properties of Boroxine Anhydride and Boronate Ester Materials: Model Systems for the Diagnostic Characterization of Covalent Organic Frameworks. Chem. Mater. 2014, 26 (12), 3781– 3795,  DOI: 10.1021/cm5013679
    Google Scholar
    43
    Vibrational Properties of Boroxine Anhydride and Boronate Ester Materials: Model Systems for the Diagnostic Characterization of Covalent Organic Frameworks
    Smith, Merry K.; Northrop, Brian H.
    Chemistry of Materials (2014), 26 (12), 3781-3795CODEN: CMATEX; ISSN:0897-4756. (American Chemical Society)
    The vibrational characteristics of 28 different boronic acid, boroxine anhydride, and boronate ester species have been systematically investigated using a combination of exptl. IR spectroscopy and computational modeling. IR bands characteristic to each boron-contg. functionality have been categorized and assigned in conjunction with d. functional theory (B3LYP/6-31G(d)), with the aim of better understanding and distinguishing the vibrational characteristics of covalent org. frameworks (COFs) built from boronic acids. In several cases, vibrational assignments differ from those previously reported in the literature on boronic acid-based COFs. Vibrations commonly regarded as diagnostic for one functionality are found in regions of the IR spectrum where other functionalities also show characteristic peaks. The collective exptl. and computational results reveal that several alternative bands in the IR region can be used to more diagnostically distinguish between boronic acid, boroxine anhydride, and boronate ester species. The results presented herein provide the tools for straightforward characterization of boroxine anhydride and boronate ester species using IR spectroscopy. The results can be applied to addnl. theor. studies of larger COF-like assemblies as well as the anal. of other boronic-acid-based materials.
  44. 44
    Qin, Y.; Cui, C.; Jäkle, F. Silylated Initiators for the Efficient Preparation of Borane-End-Functionalized Polymers via ATRP. Macromolecules 2007, 40 (5), 1413– 1420,  DOI: 10.1021/ma061704h
    Google Scholar
    44
    Silylated Initiators for the Efficient Preparation of Borane-End-Functionalized Polymers via ATRP
    Qin, Yang; Cui, Chengzhong; Jaekle, Frieder
    Macromolecules (2007), 40 (5), 1413-1420CODEN: MAMOBX; ISSN:0024-9297. (American Chemical Society)
    Borane-end-functionalized polymers were prepd. through atom transfer radical polymn. (ATRP) of styrene using a silylated initiator, 1-bromo-1-(4-trimethylsilylphenyl)ethane (PEB-SiMe3). The SiMe3 end groups were then exchanged with BBr3, and then modified with nucleophiles. Ditelechelic α,ω-borane-functionalized polymers were obtained through atom transfer radical coupling (ATRC) of the silane-end-functionalized polymers followed by exchange with BBr3 and subsequent reaction with nucleophiles. Self-assembly of the borane-functionalized mono- and ditelechelic polymers into supramol. structures by reversible noncovalent and covalent interactions including Lewis acid-base complexation and boroxine formation was explored.
  45. 45
    Kim, C.; Ejima, H.; Yoshie, N. Polymers with autonomous self-healing ability and remarkable reprocessability under ambient humidity conditions. J. Mater. Chem. A 2018, 6 (40), 19643– 19652,  DOI: 10.1039/C8TA04769C
    Google Scholar
    45
    Polymers with autonomous self-healing ability and remarkable reprocessability under ambient humidity conditions
    Kim, Chaehoon; Ejima, Hirotaka; Yoshie, Naoko
    Journal of Materials Chemistry A: Materials for Energy and Sustainability (2018), 6 (40), 19643-19652CODEN: JMCAET; ISSN:2050-7496. (Royal Society of Chemistry)
    The use of moisture in self-healing polymeric materials is a very attractive option given the practical environments in which the materials are used. Herein, we incorporated tetrahedral boronate-esters bearing B-N dative bonds as dynamic crosslinks into polymers, which led to moisture-induced self-healing abilities in their bulk states. Owing to the higher rate of ester formation over tetrahedral boronate-ester hydrolysis under wet conditions, these polymers invariably maintain a sufficient no. of dynamic crosslinks to facilitate a combination of autonomous healing behavior and mech. strength, which makes them unique compared to other previously developed water-triggered self-healing polymers. The self-healed materials maintain good mech. properties, with fracture stresses of ∼2 MPa, and aging of the cut surfaces does not affect their healing efficiency. Furthermore, the tetrahedral boronate-ester bonds exhibit dual stimuli-responsive dynamic behavior triggered by either moisture or heat, resulting in network polymers with remarkable reprocessabilities.
  46. 46
    Silverstein, R. M.; Webster, F. X.; Kiemle, D. J.; Bryce, D. L. Spectrometric Identification of Organic Compounds; John Wiley & Sons: 2015.
    Google Scholar
    There is no corresponding record for this reference.
  47. 47
    Foran, G. Y.; Harris, K. J.; Brook, M. A.; Macphail, B.; Goward, G. R. Solid State NMR Study of Boron Coordination Environments in Silicone Boronate (SiBA) Polymers. Macromolecules 2019, 52 (3), 1055– 1064,  DOI: 10.1021/acs.macromol.8b02442
    Google Scholar
    47
    Solid State NMR Study of Boron Coordination Environments in Silicone Boronate (SiBA) Polymers
    Foran, Gabrielle Y.; Harris, Kristopher J.; Brook, Michael A.; MacPhail, Benjamin; Goward, Gillian R.
    Macromolecules (Washington, DC, United States) (2019), 52 (3), 1055-1064CODEN: MAMOBX; ISSN:0024-9297. (American Chemical Society)
    Silicone polymers possess very unusual properties when compared to org. polymers. The addn. of grafted boronic acid groups allows for elastomeric film formation through self-assocn. and enhances compatibility with biol. systems by increasing elastomer miscibility with aq. systems, pH tunability, and the ability to bind to saccharides. Boronic acid dimerization was reported to be the origin of crosslinking in silicone boronic acids, but the boron environments involved in this process remain poorly understood. Solid state 11B NMR was used to investigate the boron coordination environments in these materials. 11B quadrupolar line shape fitting, a method previously used to characterize minerals and amorphous glasses, revealed structural information, including coordination no. and coordination sphere symmetry. Chain extension in these materials was attributed to hydrogen bonding between boronic acids and could be identified by the presence of three-coordinate boron sites. Crosslinking between boronic acid sites through four-coordinate, dative bonded boron centers was found to be the origin of elastomer formation; the oxygen Lewis bases on the silicone backbone do not appear to play a role. The proportion of boronic acid in the material and location of the boronic acid sites-telechelic vs. pendant-both impacted crosslinking in these materials.
  48. 48
    Parks, D. J.; Piers, W. E.; Parvez, M.; Atencio, R.; Zaworotko, M. J. Synthesis and Solution and Solid-State Structures of Tris(pentafluorophenyl)borane Adducts of PhC(O)X (X = H, Me, OEt, NPri2). Organometallics 1998, 17 (7), 1369– 1377,  DOI: 10.1021/om9710327
    Google Scholar
    48
    Synthesis and Solution and Solid-State Structures of Tris(pentafluorophenyl)borane Adducts of PhC(O)X (X = H, Me, OEt, NPri2)
    Parks, Daniel J.; Piers, Warren E.; Parvez, Masood; Atencio, Reinaldo; Zaworotko, Michael J.
    Organometallics (1998), 17 (7), 1369-1377CODEN: ORGND7; ISSN:0276-7333. (American Chemical Society)
    Reaction of the highly electrophilic borane B(C6F5)3 with the carbonyl Lewis bases benzaldehyde, acetophenone, Et benzoate, and N,N-diisopropylbenzamide led to isolation of the cryst. adducts 1-H, 1-Me, 1-OEt, and 1-NPr, resp., in good to excellent yields (63-89%). Equil. measurements and exchange expts. indicated that the order of basicity (from highest to lowest) of these bases toward B(C6F5)3 follows the order N,N-diisopropylbenzamide > benzaldehyde > acetophenone > Et benzoate. The soln. and solid-state structures were probed to rationalize these observations. In soln., the borane coordinates to the carbonyl lone pair syn to H and Me in the aldehyde and ketone adducts, as indicated by 1H/19F NOE difference expts. The same coordination geometry was obsd. in the solid state upon x-ray diffraction anal. of the two adducts. The added front strain assocd. with the ketone adduct (C-O-B =133.6(3)° vs 126.7(5)° for the benzaldehyde complex) accounts for the obsd. order of basicity with these two bases. For Et benzoate and N,N-diisopropylbenzamide, the borane coordinates syn to the Ph group in both soln. and the solid state. In addn. to the carbonyl oxygen-boron interaction, the two complexes engage in a π-stacking interaction between one of the borane C6F5 rings and the syn Ph group. In addn. to the structural proof of this interaction in the solid state, variable-temp. 19F NMR expts. suggest it is important in the soln. structures of these adducts as well.
  49. 49
    Komon, Z. J. A.; Bu, X.; Bazan, G. C. Synthesis of Butene-Ethylene and Hexene-Butene-Ethylene Copolymers from Ethylene via Tandem Action of Well-Defined Homogeneous Catalysts. J. Am. Chem. Soc. 2000, 122 (8), 1830– 1831,  DOI: 10.1021/ja994222c
    Google Scholar
    49
    Synthesis of butene-ethylene and hexene-butene-ethylene copolymers from ethylene via tandem action of well-defined homogeneous catalysts
    Komon, Zachary J. A.; Bu, Xianhui; Bazan, Guillermo C.
    Journal of the American Chemical Society (2000), 122 (8), 1830-1831CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)
    A tandem catalysis system for the synthesis of polyethylene with Et or with Et and Bu branches was developed based on the well-defined homogeneous catalysts [(C6H5)2PC6H4C(OB(C6F5)3)O-κ2P,O]Ni(η3-CH2CMeCH2) and {[(η5-C5Me4)SiMe2(η1-NCMe3)]TiMe}{MeB(C6F5)3}. Their activity to produce butene-ethylene copolymers from ethylene was studied with respect to branching percentage. Me aluminoxane was no longer required and the branching in the polymer structure depended linearly from the ratio of the 2 precatalysts. Extensive supporting material (exptl. procedures, 13C NMR data of polymers, x-ray data for Ni catalyst) is available via the Internet.
  50. 50
    Pringsheim, E.; Terpetschnig, E.; Piletsky, S. A.; Wolfbeis, O. S. A Polyaniline with Near-Infrared Optical Response to Saccharides. Adv. Mater. 1999, 11 (10), 865– 868,  DOI: 10.1002/(SICI)1521-4095(199907)11:10<865::AID-ADMA865>3.0.CO;2-B
    Google Scholar
    50
    A polyaniline with near-infrared optical response to saccharides
    Pringsheim, Erika; Terpetschnig, Ewald; Piletsky, Sergey A.; Wolfbeis, Otto S.
    Advanced Materials (Weinheim, Germany) (1999), 11 (10), 865-868CODEN: ADVMEW; ISSN:0935-9648. (Wiley-VCH Verlag GmbH)
    A sugar-binding polymer film capable of continuous sensing was prepd. by copolymn. of aniline and 3-aminophenylboronic acid and ammonium peroxodisulfate oxidn. Its absorption spectrum between 500-800 nm undergoes large changes on addn. of various saccharides (glucose, fructose, sorbitol, mannitol, saccharose, and glycerol) at neutral pH, changes which are dependent on the saccharide conc. and are fully reversible. These films represent an interesting alternative to enzyme-based glucose sensors because of their ease of prepn., compatibility with light emitting devices and diode laser light sources, and their thermal and temporal stability.
  51. 51
    Liu, H.; Li, Y.; Sun, K.; Fan, J.; Zhang, P.; Meng, J.; Wang, S.; Jiang, L. Dual-Responsive Surfaces Modified with Phenylboronic Acid-Containing Polymer Brush To Reversibly Capture and Release Cancer Cells. J. Am. Chem. Soc. 2013, 135 (20), 7603– 7609,  DOI: 10.1021/ja401000m
    Google Scholar
    51
    Dual-Responsive Surfaces Modified with Phenylboronic Acid-Containing Polymer Brush To Reversibly Capture and Release Cancer Cells
    Liu, Hongliang; Li, Yingying; Sun, Kang; Fan, Junbing; Zhang, Pengchao; Meng, Jingxin; Wang, Shutao; Jiang, Lei
    Journal of the American Chemical Society (2013), 135 (20), 7603-7609CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)
    Artificial stimuli-responsive surfaces that can mimic the dynamic function of living systems have attracted much attention. However, there exist few artificial systems capable of responding to dual- or multistimulation as the natural system does. Herein, we synthesize a pH and glucose dual-responsive surface by grafting poly(acrylamidophenylboronic acid) (polyAAPBA) brush from aligned silicon nanowire (SiNW) array. The as-prepd. surface can reversibly capture and release targeted cancer cells by precisely controlling pH and glucose concn., exhibiting dual-responsive AND logic. In the presence of 70 mM glucose, the surface is pH responsive, which can vary from a cell-adhesive state to a cell-repulsive state by changing the pH from 6.8 to 7.8. While keeping the pH at 7.8, the surface becomes glucose responsive-capturing cells in the absence of glucose and releasing cells by adding 70 mM glucose. Through simultaneously changing the pH and glucose concn. from pH 6.8/0 mM glucose to pH 7.8/70 mM glucose, the surface is dual responsive with the capability to switch between cell capture and release for at least 5 cycles. The cell capture and release process on this dual-responsive surface is noninvasive with cell viability higher than 95%. Moreover, topog. interaction between the aligned SiNW array and cell protrusions greatly amplifies the responsiveness and accelerates the response rate of the dual-responsive surface between cell capture and release. The responsive mechanism of the dual-responsive surface is systematically studied using a quartz crystal microbalance, which shows that the competitive binding between polyAAPBA/sialic acid and polyAAPBA/glucose contributes to the dual response. Such dual-responsive surface can significantly impact biomedical and biol. applications including cell-based diagnostics, in vivo drug delivery, etc.
  52. 52
    Barriet, D.; Yam, C. M.; Shmakova, O. E.; Jamison, A. C.; Lee, T. R. 4-Mercaptophenylboronic Acid SAMs on Gold: Comparison with SAMs Derived from Thiophenol, 4-Mercaptophenol, and 4-Mercaptobenzoic Acid. Langmuir 2007, 23 (17), 8866– 8875,  DOI: 10.1021/la7007733
    Google Scholar
    52
    4-Mercaptophenylboronic Acid SAMs on Gold: Comparison with SAMs Derived from Thiophenol, 4-Mercaptophenol, and 4-Mercaptobenzoic Acid
    Barriet, David; Yam, Chi Ming; Shmakova, Olga E.; Jamison, Andrew C.; Lee, T. Randall
    Langmuir (2007), 23 (17), 8866-8875CODEN: LANGD5; ISSN:0743-7463. (American Chemical Society)
    We report the formation and characterization of self-assembled monolayers (SAMs) derived from the adsorption of 4-mercaptophenylboronic acid (MPBA) on gold. For comparison, SAMs derived from the adsorption of thiophenol (TP), 4-mercaptophenol (MP), and 4-mercaptobenzoic acid (MBA) were also examd. The structure and properties of the SAMs were evaluated by ellipsometry, contact-angle goniometry, polarization-modulation IR reflection-absorption spectroscopy (PM-IRRAS), and XPS. Specifically, ellipsometry was used to assess the formation of monolayer films, and contact angle measurements were used to det. the surface hydrophilicity and homogeneity. Sep., PM-IRRAS was used to evaluate the mol. compn. and orientation as well as the intermol. hydrogen bonding within the SAMs. Finally, XPS was used to evaluate the film compn. and surface coverage (i.e., packing d.), which was obsd. to increase in the following order: TP < MP < MPBA < MBA. A rationalization for the obsd. packing differences is presented. The XPS data indicate further that ultrahigh vacuum conditions induce the partial dehydration of MPBA SAMs with the concomitant formation of surface boronic anhydride species. Overall, the anal. data collectively show that the MPBA moieties in the SAMs exist in the acid form rather than the anhydride form under ambient lab. conditions. Furthermore, stability studies find that MPBA SAMs are surprisingly labile in basic soln., where the terminal B-C bonds are cleaved by the attack of hydroxide ion and strongly basic amine nucleophiles. The unanticipated lability obsd. here should be considered by those wishing to use MPBA moieties in carbohydrate-sensing applications.
  53. 53
    Sana, M.; Leroy, G.; Wilante, C. Enthalpies of formation and bond energies in lithium, beryllium, and boron derivatives. 2. Dative, single, and triple bonds. Organometallics 1992, 11 (2), 781– 787,  DOI: 10.1021/om00038a042
    Google Scholar
    53
    Enthalpies of formation and bond energies in lithium, beryllium, and boron derivatives. 2. Dative, single, and triple bonds
    Sana, Michel; Leroy, Georges; Wilante, Claude
    Organometallics (1992), 11 (2), 781-7CODEN: ORGND7; ISSN:0276-7333.
    For a set of small XYHn singlet-state mols. (where X stands for Li, Be, or B and Y is one of the second-row atoms), the enthalpies of formation at the MP4(sdtq)/6-311++G(3df,2p) level by using MP2(full)/6-31G(d,p) fully optimized structures were calcd. At this level of theory, the heats of formation are expected to be in the range of the so-called chem. accuracy (±1 kcal/mol). Some alkyl derivs. of the previous XYHn compds. were studied at the RHF/6-31G(d) level (with fully optimized geometries). The theor. enthalpies of formation reproduce the available exptl. results quite satisfactorily. In addn. to compds. with usual dative single bonds, the mols. with covalent (nondative) single B-N and B-O bonds were also described. The available (exptl. and theor.) data to calc. new bond energies for lithium, beryllium, and boron derivs. were used.
  54. 54
    Chen, H.; Yao, X.; Ma, X.; Tian, H. Amorphous, Efficient, Room-Temperature Phosphorescent Metal-Free Polymers and Their Applications as Encryption Ink. Adv. Opt. Mater. 2016, 4 (9), 1397– 1401,  DOI: 10.1002/adom.201600427
    Google Scholar
    54
    Amorphous, Efficient, Room-Temperature Phosphorescent Metal-Free Polymers and Their Applications as Encryption Ink
    Chen, Hui; Yao, Xuyang; Ma, Xiang; Tian, He
    Advanced Optical Materials (2016), 4 (9), 1397-1401CODEN: AOMDAX; ISSN:2195-1071. (Wiley-VCH Verlag GmbH & Co. KGaA)
    In this paper phosphorescent metal-free polymers were synthesized by radical binary copolymn., by employing acrylamide and room-temp. phosphorescence (RTP) phosphors contg. a 2-bromo-5-hydroxybenzaldehyde deriv., a α-bromonaphthalene deriv., and a 4-bromo-1,8-naphthalic anhydride deriv., resp. Their applications as encryption ink are demonstrated as well. The hydrogen bonding between polymeric chains greatly enhances the RTP intensity. The crosslinking degree of the network formed by N,N-di-Me acrylamide was very poor, which resulted in the decrease of luminescent decay lifetimes at 580 nm. The hydrogen bonding between polymeric chains greatly enhances the RTP intensity. Hydrogen-bond crosslinking between the polymeric chains not only immobilized the RTP phosphors, but also endowed the materials with reversibly controllable characteristics due to the nature of noncovalent interactions. As a result, the materials exhibit water-responsive properties.
  55. 55
    Yin, X.; Stöver, H. D. H. Hydrogel Microspheres by Thermally Induced Coacervation of Poly(N, N-dimethylacrylamide-co-glycidyl methacrylate) Aqueous Solutions. Macromolecules 2003, 36 (26), 9817– 9822,  DOI: 10.1021/ma034809i
    Google Scholar
    55
    Hydrogel Microspheres by Thermally Induced Coacervation of Poly(N,N-dimethylacrylamide-co-glycidyl methacrylate) Aqueous Solutions
    Yin, Xiangchun; Stoever, Harald D. H.
    Macromolecules (2003), 36 (26), 9817-9822CODEN: MAMOBX; ISSN:0024-9297. (American Chemical Society)
    Aq. solns. of poly(N,N-dimethylacrylamide-co-glycidyl methacrylate) (DMA-GMA) are shown to undergo liq.-liq. phase sepn. upon heating. The phase transition temps. as measured by the cloud point method decreased with increasing levels of the hydrophobic GMA comonomer. The initially formed coacervate microdroplets could be cross-linked by addn. of polyamines. The morphol. of the resulting hydrogel microspheres depends on both coacervation conditions and crosslinking conditions. Specifically, colloidally stable microspheres were formed at temps. slightly above the phase transition temps., while agglomeration took place at higher temps. Low mol. wt. polyamines are effective internal cross-linkers for the coacervate droplets, while higher mol. wt. polyamines resulted in agglomeration. Addn. of sodium dodecyl sulfate increased the phase transition temps. of polymer solns. dramatically, while addn. of poly(vinylpyrrolidone) (PVP) did not affect the phase sepn. temps. and could be used as a steric stabilizer.
  56. 56
    Gan, N.; Shi, H.; An, Z.; Huang, W. Recent Advances in Polymer-Based Metal-Free Room-Temperature Phosphorescent Materials. Adv. Funct. Mater. 2018, 28 (51), 1802657,  DOI: 10.1002/adfm.201802657
    Google Scholar
    There is no corresponding record for this reference.
  57. 57
    Carey, R. I.; Folkers, J. P.; Whitesides, G. M. Self-Assembled Monolayers Containing. omega.-Mercaptoalkyl boronic Acids Adsorbed onto Gold Form a Highly Cross-Linked, Thermally Stable Borate Glass Surface. Langmuir 1994, 10 (7), 2228– 2234,  DOI: 10.1021/la00019a033
    Google Scholar
    57
    Self-Assembled Monolayers Containing ω-Mercaptoalkyl boronic Acids Adsorbed onto Gold Form a Highly Cross-Linked, Thermally Stable Borate Glass Surface
    Carey, Robert I.; Folkers, John P.; Whitesides, George M.
    Langmuir (1994), 10 (7), 2228-34CODEN: LANGD5; ISSN:0743-7463.
    This paper describes the prepn. and properties of self-assembled monolayers (SAMs) obtained by the adsorption of 11-mercaptoundecanyl-1-boronic acid, HS(CH2)11B(OH)2 onto the surface of gold substrates. In soln. in dry hydrocarbon solvents, 11-mercaptoundecanyl-1-boronic acid reversibly forms a tri-ω-mercaptoalkylboroxine that adsorbs onto gold and forms a hydrophobic boroxine bilayer: this bilayer is marginally stable in air; it can be completely hydrolyzed to a monolayer in aq. ethanol, yielding a hydrophilic, 17-Å-thick SAM that presents boronic acid groups at its surface. Under water-satd. cyclooctane, SAMs exposing the boronic acid groups do not titrate appreciably over a pH range of 0 to 11-i.e., the contact angle is independent of the pH of the contacting aq. soln. At pH 13-14, there is a sharp increase in the hydrophilicity of the SAM, indicating an onset of ionization of the boronic acid groups. In dry hydrocarbon solvents or under vacuum, the boronic acid tail groups dehydrate rapidly and reversibly and form a cross-linked borate glass at the surface. At 147° in hexadecane, SAMs having this cross-linked borate glass as a surface are at least 5 times more stable to thermal desorption than SAMs of the structurally analogous 11-hydroxyundecane-1-thiol. The boronic acid/anhydride groups of SAMs of 1 can be derivatized with solns. of certain cis-diols (esp. pinanediol), catechols, and alkyltrichlorosilanes to yield hydrophobic structures consisting of an inner monomer derived from 1 and an outer partial monolayer of the boronate ester or the alkylsiloxane.
  58. 58
    Ma, X.; Xu, C.; Wang, J.; Tian, H. Amorphous Pure Organic Polymers for Heavy-Atom-Free Efficient Room-Temperature Phosphorescence Emission. Angew. Chem., Int. Ed. 2018, 57 (34), 10854– 10858,  DOI: 10.1002/anie.201803947
    Google Scholar
    58
    Amorphous Pure Organic Polymers for Heavy-Atom-Free Efficient Room-Temperature Phosphorescence Emission
    Ma, Xiang; Xu, Chao; Wang, Jie; Tian, He
    Angewandte Chemie, International Edition (2018), 57 (34), 10854-10858CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)
    Pure org., heavy-atom-free room-temp. phosphorescence (RTP) materials have attracted much attention and have potential applications in photoelec. and biochem. material fields owing to their rich excited state properties. They offer long luminescent lifetime, diversified design, and facile prepn. However, recent achievements of efficient phosphorescence under ambient conditions mainly focus on ordered crystal lattices or embedding into rigid matrixes, which require strict growth conditions and have poor reproducibility. Herein, we developed a concise approach to give RTP with a decent quantum yield and ultralong phosphorescence lifetime in the amorphous state by radical binary copolymn. of acrylamide and different phosphors with oxygen-contg. functional groups. The crosslinked hydrogen-bonding networks between the polymeric chains immobilize phosphors to suppress non-radiative transitions and provide a microenvironment to shield quenchers.
  59. 59
    Zhang, X.; Xie, T.; Cui, M.; Yang, L.; Sun, X.; Jiang, J.; Zhang, G. General Design Strategy for Aromatic Ketone-Based Single-Component Dual-Emissive Materials. ACS Appl. Mater. Interfaces 2014, 6 (4), 2279– 2284,  DOI: 10.1021/am405209w
    Google Scholar
    59
    General Design Strategy for Aromatic Ketone-Based Single-Component Dual-Emissive Materials
    Zhang, Xuepeng; Xie, Tongqing; Cui, Minxin; Yang, Li; Sun, Xingxing; Jiang, Jun; Zhang, Guoqing
    ACS Applied Materials & Interfaces (2014), 6 (4), 2279-2284CODEN: AAMICK; ISSN:1944-8244. (American Chemical Society)
    Materials with both fluorescence and room-temp. phosphorescence (RTP) can be useful in the field of optoelectronics. Here the authors present a general strategy, taking advantage of carbonyl compds., which have been known to possess efficient intersystem crossing with high triplet state yield, as well as a strongly fluorescent intramol. charge-transfer (ICT) state, to produce materials with both fluorescence and RTP at the same time, or dual-emission. In the presented model systems, in order to generate a suitable ICT state, Lewis acid binding to arom. ketone derivs. has been proved to be a viable method. The authors have selected AlCl3, BCl3, BF3, and GdCl3 as binding Lewis acids, in that they exhibit sufficiently strong binding affinity toward the arom. ketone derivs. to afford stable complexes and yet do not possess low-lying electronic transitions vs the ligands. The authors have successfully obsd. dual-emission from these designed complexes in polymers, which act to suppress competitive thermal decay at room temp. One of the complexes is particularly interesting as it is dual-emissive in the cryst. state. Single-crystal XRD reveals that the mol. forms multiple hydrogen bonds with its neighbors in crystals, which may significantly enhance the rigidity of the environment.
  60. 60
    Liu, Y.; Zhao, J.; Iagatti, A.; Bussotti, L.; Foggi, P.; Castellucci, E.; Di Donato, M.; Han, K.-L. A Revisit to the Orthogonal Bodipy Dimers: Experimental Evidence for the Symmetry Breaking Charge Transfer-Induced Intersystem Crossing. J. Phys. Chem. C 2018, 122 (5), 2502– 2511,  DOI: 10.1021/acs.jpcc.7b10213
    Google Scholar
    60
    A Revisit to the Orthogonal Bodipy Dimers: Experimental Evidence for the Symmetry Breaking Charge Transfer-Induced Intersystem Crossing
    Liu, Ya; Zhao, Jianzhang; Iagatti, Alessandro; Bussotti, Laura; Foggi, Paolo; Castellucci, Elena; Di Donato, Mariangela; Han, Ke-Li
    Journal of Physical Chemistry C (2018), 122 (5), 2502-2511CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)
    A series of Bodipy dimers with orthogonal conformation were prepd. The photophys. properties were studied with steady-state and time-resolved transient spectroscopies. We found the triplet-state quantum yield is highly dependent on the solvent polarity in the orthogonally linked sym. Bodipy dimers, and the intersystem crossing (ISC) is efficient in solvents with moderate polarity. The photoinduced symmetry-breaking charge transfer (SBCT) in polar solvents was confirmed by femtosecond transient absorption spectroscopy, with the charge sepn. (CS) kinetics on the order of a few picoseconds and the charge recombination (CR) process occurring on the nanosecond time scale(coating process) in dichloromethane. These observations are supported by the calcn. of the charge sepd. state (CSS) energy levels, which are high in nonpolar solvents, and lower in polar solvents, thus the CR-induced ISC has the largest driven force in solvents with moderate polarity. These results clarify the mechanism of SOCT-ISC in the orthogonally sym. Bodipy dimers. The acquired information, relating mol. structure and ISC property, will be useful for devising new strategies to induce ISC in heavy atom-free org. chromophores.
  61. 61
    Iwata, S.; Tanaka, J.; Nagakura, S. Phosphorescence of the Charge-Transfer Triplet States of Some Molecular Complexes. J. Chem. Phys. 1967, 47 (7), 2203– 2209,  DOI: 10.1063/1.1703292
    Google Scholar
    61
    Phosphorescence of the charge-transfer triplet states of some molecular complexes
    Iwata, Suehiro; Tanaka, Jiro; Nagakura, Saburo
    Journal of Chemical Physics (1967), 47 (7), 2203-9CODEN: JCPSA6; ISSN:0021-9606.
    The phosphorescence spectra of some charge-transfer complexes were studied in glassy soln. at 77°K. Long-lived emission spectra which were different from the phosphorescence spectra of the constituent mols. were observed for the 1,2,4,5-tetracyanobenzene complexes with mesitylene, durene, and hexamethylbenzene. The max. of the long-lived emission spectra were found to shift to lower frequencies as the ionization potential of the donor was decreased; e.g., max. appear at 19.8, 19.5, and 18.3 (×103 cm.-1) in the complexes with mesitylene, durene, and hexamethylbenzene, resp. This shift is parallel to that observed for charge-transfer fluorescence spectra which exhibit a mirror-image relation with the corresponding absorption spectra. Similar long-lived emission spectra were also observed for complexes contg. pyromellitic dianhydride, tetrachlorophthalic anhydride, and phthalic anhydride as electron acceptors. A combination of theory and expt. indicates that the long-lived emission is attributable to a transition from a triplet state of charge-transfer character. This is the 1st observation of a "charge-transfer triplet state." The lifetime of the phosphorescence due to the charge-transfer triplet state was measured. The observed lifetime decreases with increasing donor ability for a series of complexes with a fixed electron acceptor. The mechanism of singlet-triplet mixing in the charge-transfer complexes is discussed.
  62. 62
    Snyder, R.; Testa, A. C. Reversible phosphorescence quenching of some aromatic ketones. J. Phys. Chem. 1979, 83 (23), 3041– 3044,  DOI: 10.1021/j100486a022
    Google Scholar
    62
    Reversible phosphorescence quenching of some aromatic ketones
    Snyder, R.; Testa, A. C.
    Journal of Physical Chemistry (1979), 83 (23), 3041-4CODEN: JPCHAX; ISSN:0022-3654.
    An investigation of the phosphorescence behavior of Ph2CO, anthrone and fluorenone (I) and their 1:1 EDA (electron donor-acceptor) complexes with BCl3 reveals that (a) complexation generates a new charge-transfer phosphorescence appearing at 505 nm in the 1st 2 mols., and (b) complexation can readily be reversed to regenerate the phosphorescence spectrum of the free ketone, the electron donor in these studies. With I the lack of phosphorescence from the complex may be due to the charge-transfer state lying above the lowest nonphosphorescing 3π,π state of I. Formation consts. and phosphorescence quantum yields for the EDA complexes of Ph2CO and anthrone were detd.
  63. 63
    Mo, Y.; Song, L.; Wu, W.; Zhang, Q. Charge Transfer in the Electron Donor-Acceptor Complex BH3NH3. J. Am. Chem. Soc. 2004, 126 (12), 3974– 3982,  DOI: 10.1021/ja039778l
    Google Scholar
    63
    Charge Transfer in the Electron Donor-Acceptor Complex BH3NH3
    Mo, Yirong; Song, Lingchun; Wu, Wei; Zhang, Qianer
    Journal of the American Chemical Society (2004), 126 (12), 3974-3982CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)
    As a simple yet strongly binding electron donor-acceptor (EDA) complex, BH3NH3 serves as a good example to study the electron pair donor-acceptor complexes. We employed both the ab initio valence bond (VB) and block-localized wave function (BLW) methods to explore the electron transfer from NH3 to BH3. Conventionally, EDA complexes have been described by two diabatic states: one neutral state and one ionic charge-transferred state. Ab initio VB SCF (VBSCF) computations generate the energy profiles of the two diabatic states together with the adiabatic (ground) state. Our calcns. evidently demonstrated that the electron transfer between NH3 and BH3 falls in the abnormal regime where the reorganization energy is less than the exoergicity of the reaction. The nature of the NH3-BH3 interaction is probed by an energy decompn. scheme based on the BLW method. We found that the variation of the charge-transfer energy with the donor-acceptor distance is insensitive to the computation levels and basis sets, but the estn. of the amt. of electron transferred heavily depends on the population anal. procedures. The recent resurgence of interest in the nature of the rotation barrier in ethane prompted us to analyze the conformational change of BH3NH3, which is an isoelectronic system with ethane. We found that the preference of the staggered structure over the eclipsed structure of BH3NH3 is dominated by the Pauli exchange repulsion.
  64. 64
    Yoshino, J.; Kano, N.; Kawashima, T. Fluorescent azobenzenes and aromatic aldimines featuring an N-B interaction. Dalton Trans. 2013, 42 (45), 15826– 15834,  DOI: 10.1039/c3dt51689j
    Google Scholar
    64
    Fluorescent azobenzenes and aromatic aldimines featuring an N-B interaction
    Yoshino, Junro; Kano, Naokazu; Kawashima, Takayuki
    Dalton Transactions (2013), 42 (45), 15826-15834CODEN: DTARAF; ISSN:1477-9226. (Royal Society of Chemistry)
    A review. Azobenzenes are constituents of the commonly and widely used azo dyes. Many dyes, except for the azo dyes, have been utilized for fluorescent materials. However, there are only a few fluorescent azobenzene derivs. and their fluorescence efficiencies are quite low. The current perspective provides an account of the fluorescent azobenzenes and arom. aldimines featuring an N-B interaction. Incorporation of the intramol. N-B interaction by using the bis(pentafluorophenyl)boryl group makes the azobenzenes and arom. aldimines fluorescent with a range of colors. Some of them fluoresce with extraordinarily high fluorescence quantum yields. Their synthesis, structures, fluorescence properties, and applications are discussed.
  65. 65
    Yoshino, J.; Kano, N.; Kawashima, T. Synthesis of the most intensely fluorescent azobenzene by utilizing the B-N interaction. Chem. Commun. 2007, (6), 559– 561,  DOI: 10.1039/B615966D
    Google Scholar
    65
    Synthesis of the most intensely fluorescent azobenzene by utilizing the B-N interaction
    Yoshino, Junro; Kano, Naokazu; Kawashima, Takayuki
    Chemical Communications (Cambridge, United Kingdom) (2007), (6), 559-561CODEN: CHCOFS; ISSN:1359-7345. (Royal Society of Chemistry)
    Chelate 2-boryl-substituted azobenzenes exhibit intense fluorescence at 500-520 nm with quantum yields of 0.23-0.76, being excited at 380-440 nm. Lithiation/borylation of 2-iodo-4'-R-azobenzenes (1, 4; R = H, OMe) affords diaryl(4-R-phenylazo-κN2-phenyl-κC)boranes (3a, 3c, aryl = C6F5, R = H, OMe; 3b, aryl = 4-FC6H4, R = H). A boron-substituted azobenzene 3c, (E)-[2-(4-methoxyphenylazo)phenyl]bis(pentafluorophenyl)borane, presented the most intense fluorescence among the azobenzene derivs.
  66. 66
    Paddon-Row, M. N.; Anderson, C. D.; Houk, K. N. Computational Evaluation of Enantioselective Diels-Alder Reactions Mediated by Corey’s Cationic Oxazaborolidine Catalysts. J. Org. Chem. 2009, 74 (2), 861– 868,  DOI: 10.1021/jo802323p
    Google Scholar
    66
    Computational Evaluation of Enantioselective Diels-Alder Reactions Mediated by Corey's Cationic Oxazaborolidine Catalysts
    Paddon-Row, Michael N.; Anderson, Christopher D.; Houk, K. N.
    Journal of Organic Chemistry (2009), 74 (2), 861-868CODEN: JOCEAH; ISSN:0022-3263. (American Chemical Society)
    The cationic oxazaborolidine-catalyzed Diels-Alder reactions of butadiene and five dienophiles were studied using d. functional theory (B3LYP/6-31G(d)). In each case, the computational results successfully reproduce the exptl. obsd. sense of stereoinduction and enantiomeric ratio. The computed structures of the lowest energy Lewis acid-carbonyl complexes and Lewis acid-transition state complexes are closely related to the models for stereoselection proposed by Corey and co-workers.
  67. 67
    Zhao, C.; Jin, Y.; Wang, J.; Cao, X.; Ma, X.; Tian, H. Heavy-atom-free amorphous materials with facile preparation and efficient room-temperature phosphorescence emission. Chem. Commun. 2019, 55 (37), 5355– 5358,  DOI: 10.1039/C9CC01594A
    Google Scholar
    67
    Heavy-atom-free amorphous materials with facile preparation and efficient room-temperature phosphorescence emission
    Zhao, Changxing; Jin, Yanhuan; Wang, Jie; Cao, Xiaoming; Ma, Xiang; Tian, He
    Chemical Communications (Cambridge, United Kingdom) (2019), 55 (37), 5355-5358CODEN: CHCOFS; ISSN:1359-7345. (Royal Society of Chemistry)
    Amorphous pure org. room-temp. phosphorescent small mols. without heavy atoms, based on the intermol. hydrogen bonding network for the immobilization of luminophores, were designed and facilely prepd. via modification of heavy-atom-free luminophores onto β-cyclodextrin.
  68. 68
    Yang, X.; Guo, H.; Xu, X.; Sun, Y.; Zhou, G.; Ma, W.; Wu, Z. Enhancing Molecular Aggregations by Intermolecular Hydrogen Bonds to Develop Phosphorescent Emitters for High-Performance Near-Infrared OLEDs. Adv. Sci. 2019, 6 (7), 1801930,  DOI: 10.1002/advs.201801930
    Google Scholar
    68
    Enhancing Molecular Aggregations by Intermolecular Hydrogen Bonds to Develop Phosphorescent Emitters for High-Performance Near-Infrared OLEDs
    Yang Xiaolong; Guo Haoran; Xu Xianbin; Sun Yuanhui; Zhou Guijiang; Ma Wei; Wu Zhaoxin
    Advanced science (Weinheim, Baden-Wurttemberg, Germany) (2019), 6 (7), 1801930 ISSN:2198-3844.
    Phosphorescent near-infrared (NIR) organic light-emitting devices (OLEDs) have drawn increasing attention for their promising applications in the fields such as photodynamic therapy and night-vision readable displays. Here, three simple phosphorescent Pt(II) complexes are synthesized, and their intermolecular interactions are investigated in crystals and neat films by X-ray single crystal diffraction and grazing-incidence wide-angle X-ray scattering, respectively. The photophysical properties, molecular aggregation (including Pt-Pt interaction), molecular packing orientation, and electron transport ability are all influenced by the strong intermolecular hydrogen bonds. Consequently, the nondoped OLEDs based on tBu-Pt and F-Pt show electroluminescent emissions in NIR region with the highest external quantum efficiencies of 13.9% and 16.7%, respectively.
  69. 69
    Chen, J.; Yu, T.; Ubba, E.; Xie, Z.; Yang, Z.; Zhang, Y.; Liu, S.; Xu, J.; Aldred, M. P.; Chi, Z. Achieving Dual-Emissive and Time-Dependent Evolutive Organic Afterglow by Bridging Molecules with Weak Intermolecular Hydrogen Bonding. Adv. Opt. Mater. 2019, 7 (7), 1801593,  DOI: 10.1002/adom.201801593
    Google Scholar
    There is no corresponding record for this reference.

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  2. Kelling J. Donald, Ulrick R. Gaillard, Noah Walker. On Neutral Unsaturated Ouroboric Borylenes. The Journal of Physical Chemistry A 2022, 126 (31) , 5173-5185. https://doi.org/10.1021/acs.jpca.2c04249
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  • Abstract

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    Figure 1

    Figure 1. Structural characterization of p-BAA with 4-VPBA/AA molar ratio of 1/10: FTIR spectra (a), solid-state 11B spectra (b), and B 1s XPS spectra (c). Schematic process to fabricate p-BAA-P and p-BAA-F (d).

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    Figure 2

    Figure 2. (a) Photoluminescence excitation (black), fluorescence (red), and RTP (blue) spectra of BAAs. Inset: luminescence decay lifetime at the excitation peak of 355 nm. (b) Luminescence photographs of BAA films under sunlight and 365 nm UV irradiation and after removal of UV irradiation. (c) RTP lifetimes and actual VPBA unit contents of p-BAA with different feed molar ratios. (d) XRD patterns of BAAs.

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    Figure 3

    Figure 3. (a) Chemical structure, B 1s XPS spectra as well as photoluminescence excitation (black), fluorescence (red), and RTP (blue) spectra of p-BAD. Inset: luminescence decay lifetime at the excitation peak of 355 nm. (b) Chemical structure, B 1s XPS spectra as well as photoluminescence excitation (black) and fluorescence (red) spectra of BAS.

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    Figure 4

    Figure 4. Water-enabled self-healing ability of BAA. (a) Polarizing microscope maps of the fracture to trace the healing process: the original state after cut (top) and the healed state after 1 min (bottom). (b) The film of 0.2 g can sustain a weight of 200 g before and after healing. (c) Fluorescence and phosphorescence can be observed in the healed sample. (d) Schematic illustration of the water-enabled healing process: Free functional groups are generated with the assistance of water in the surface, and then hydrogen bonds and dative bonds are re-formed across the fracture after drying.

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    Figure 5

    Figure 5. Photographs of the flower after drying and wetting under sunlight, a 365 nm UV lamp, and the removal of the UV lamp.

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  • References

    This article references 69 other publications.

    1. 1
      Xu, H.; Chen, R.; Sun, Q.; Lai, W.; Su, Q.; Huang, W.; Liu, X. Recent progress in metal-organic complexes for optoelectronic applications. Chem. Soc. Rev. 2014, 43 (10), 3259– 3302,  DOI: 10.1039/C3CS60449G
      1
      Recent progress in metal-organic complexes for optoelectronic applications
      Xu, Hui; Chen, Runfeng; Sun, Qiang; Lai, Wenyong; Su, Qianqian; Huang, Wei; Liu, Xiaogang
      Chemical Society Reviews (2014), 43 (10), 3259-3302CODEN: CSRVBR; ISSN:0306-0012. (Royal Society of Chemistry)
      A review. The design and characterization of metal-org. complexes for optoelectronic applications is an active area of research. The metal-org. complex offers unique optical and electronic properties arising from the interplay between the inorg. metal and the org. ligand. The ability to modify chem. structure through control over metal-ligand interaction on a mol. level could directly impact the properties of the complex. When deposited in thin film form, this class of materials enable the fabrication of a wide variety of low-cost electronic and optoelectronic devices. These include light emitting diodes, solar cells, photodetectors, field-effect transistors as well as chem. and biol. sensors. Here we present an overview of recent development in metal-org. complexes with controlled mol. structures and tunable properties. Advances in extending the control of mol. structures to solid materials for energy conversion and information technol. applications will be highlighted.
    2. 2
      Xu, S.; Chen, R.; Zheng, C.; Huang, W. Excited State Modulation for Organic Afterglow: Materials and Applications. Adv. Mater. 2016, 28 (45), 9920– 9940,  DOI: 10.1002/adma.201602604
      2
      Excited State Modulation for Organic Afterglow: Materials and Applications
      Xu, Shen; Chen, Runfeng; Zheng, Chao; Huang, Wei
      Advanced Materials (Weinheim, Germany) (2016), 28 (45), 9920-9940CODEN: ADVMEW; ISSN:0935-9648. (Wiley-VCH Verlag GmbH & Co. KGaA)
      Org. afterglow materials, developed recently by breaking through the difficulties in modulating ultrafast-decayed excited states, exhibit ultralong-lived emission for persistent luminescence with lifetimes of several orders of magnitude longer than traditional fluorescent and phosphorescent emissions at room temp. Their exceptional properties, namely ultralong luminescent lifetime, large Stokes shifts, facile excited state transformation, and environmentally sensitive emission, have led to a diverse range of advanced optoelectronic applications. Here, the org. afterglow is reviewed from the perspective of fundamental concepts on both phenomenon and mechanism, examg. the tech. challenges in relation to excited state tuning and lifetime elongation. In particular, the advances in material design strategies that afford a large variety of org. afterglow materials for a broad utility in optoelectronics including lighting and displays, anti-counterfeiting, optical recording, chem. sensors and bio-imaging are highlighted.
    3. 3
      Ma, X.; Wang, J.; Tian, H. Assembling-Induced Emission: An Efficient Approach for Amorphous Metal-Free Organic Emitting Materials with Room-Temperature Phosphorescence. Acc. Chem. Res. 2019, 52 (3), 738– 748,  DOI: 10.1021/acs.accounts.8b00620
      3
      Assembling-Induced Emission: An Efficient Approach for Amorphous Metal-Free Organic Emitting Materials with Room-Temperature Phosphorescence
      Ma, Xiang; Wang, Jie; Tian, He
      Accounts of Chemical Research (2019), 52 (3), 738-748CODEN: ACHRE4; ISSN:0001-4842. (American Chemical Society)
      A review. Pure org. emitting materials with room-temp. phosphorescence (RTP), showing large Stokes shifts with long emitting lifetime, low prepn. cost, good processability, and wide applications in anal., bioimaging, org. light emitting diode, and so forth, were drawing great attentions recently. Related to the design strategy for metal-free RTP materials, the phosphors contg. heavy atoms (Br, I, etc.) and other heteroatoms (O, S, etc.) to facilitate the singlet-to-triplet intersystem crossing (ISC) to populate the triplet are usually employed. Besides this factor, the pathways of nonradiative relaxation are inhibited as much as possible. Cryst. packing was the commonly used strategy to engender the rigid environment to suppress the nonradiative decay, and thus to enhance the RTP emission. Crystal RTP materials might usually be provided with not good enough repeatability and processability, which would restrict their specific practical applications special for biosystem. Amorphous metal-free RTP materials could overcome such deficiencies. Great efforts were devoted to develop challengeable amorphous metal-free materials and expand their potential applications. The main focus is on the recent progress on amorphous pure org. RTP system, focusing on the rigid effect to restrict the nonradiative decay to induce or enhance the RTP emission via supramol. interactions such as host-guest interaction and H-bonding rigid matrix. Typical host-guest assembling and supramol. polymer systems, H-binding copolymers, and small mols. for RTP emission, as well as the heavy-atom free assembling systems for RTP emission are well illustrated in this Account. Some future perspectives and research direction of the area of pure org. RTP systems are given, such as enhancement of emission quantum yield, emission color tuning, possible device applications, and the remaining challenge. Based on these amorphous RTP material examples and beyond, the authors herein would like to conclude and propose a new concept as assembling-induced emission, the key thought of which systems is control mol. motions, then control emission via supramol. dynamic assembling. This assembling-induced emission strategy is applicable in many emissive assembling systems besides such amorphous RTP materials introduced in this Account. Hopefully this concept will be a helpful guide for understanding the emissive mechanism and constructing strategy of various emissive materials.
    4. 4
      Xiao, L.; Chen, Z.; Qu, B.; Luo, J.; Kong, S.; Gong, Q.; Kido, J. Recent Progresses on Materials for Electrophosphorescent Organic Light-Emitting Devices. Adv. Mater. 2011, 23 (8), 926– 952,  DOI: 10.1002/adma.201003128
      4
      Recent progresses on materials for electrophosphorescent organic light-emitting devices
      Xiao, Lixin; Chen, Zhijian; Qu, Bo; Luo, Jiaxiu; Kong, Sheng; Gong, Qihuang; Kido, Junji
      Advanced Materials (Weinheim, Germany) (2011), 23 (8), 926-952CODEN: ADVMEW; ISSN:0935-9648. (Wiley-VCH Verlag GmbH & Co. KGaA)
      A review. Although org. light-emitting devices were commercialized as flat panel displays since 1997, only singlet excitons were emitted. Full use of singlet and triplet excitons, electrophosphorescence, has attracted increasing attentions after the premier work made by Forrest, Thompson, and co-workers. In fact, red electrophosphorescent dye has already been used in sub-display of com. mobile phones since 2003. Highly efficient green phosphorescent dye is now undergoing of commercialization. Very recently, blue phosphorescence approaching the theor. efficiency also was achieved, which may overcome the final obstacle against the commercialization of full color display and white light sources from phosphorescent materials. Combining light out-coupling structures with highly efficient phosphors (shown in the table-of-contents image), white emission with an efficiency matching that of fluorescent tubes (90 lm/W) has now been realized. It is possible to tune the color to the true white region by changing to a deep blue emitter and corresponding wide gap host and transporting material for the blue phosphor. Recent progresses in red, green, blue, and white electrophosphorescent materials for OLEDs are reviewed, with special emphasis on blue electrophosphorescent materials.
    5. 5
      Wang, Q.; Dou, X.; Chen, X.; Zhao, Z.; Wang, S.; Wang, Y.; Sui, K.; Tan, Y.; Gong, Y.; Zhang, Y.; Yuan, W. Z. Reevaluating Protein Photoluminescence: Remarkable Visible Luminescence upon Concentration and Insight into the Emission Mechanism. Angew. Chem., Int. Ed. 2019, 58 (36), 12667– 12673,  DOI: 10.1002/anie.201906226
      5
      Reevaluating protein photoluminescence: Remarkable visible luminescence upon concentration and insight into the emission mechanism
      Wang, Qian; Dou, Xueyu; Chen, Xiaohong; Zhao, Zihao; Wang, Shuang; Wang, Yunzhong; Sui, Kunyan; Tan, Yeqiang; Gong, Yongyang; Zhang, Yongming; Yuan, Wang Zhang
      Angewandte Chemie, International Edition (2019), 58 (36), 12667-12673CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)
      It is a textbook knowledge that protein photoluminescence stems from the three arom. amino acid residues of tryptophan(Trp), tyrosine (Tyr), and phenylalanine (Phe), with predominant contributions from Trp. Recently, inspired by the intrinsic emission of nonarom. amino acids and poly(amino acids) in concd. solns. and solids, we revisited protein light emission using bovine serum albumin (BSA) as a model. BSA is virtually nonemissive in dil. solns. (≤0.1 mg mL-1), but highly luminescent upon concn. or aggregation, showing unique concn.-enhanced emission and aggregation-induced emission (AIE) characteristics. Notably, apart from well-documented UV luminescence, bright blue emission is clearly obsd. Furthermore, persistent room-temp. phosphorescence (p-RTP) is achieved even in the amorphous solids under ambient conditions. This visible emission can be rationalized by the clustering-triggered emission (CTE) mechanism. These findings not only provide an in-depth understanding of the emissive properties of proteins, but also hold strong implications for further elucidating the basis of tissue autofluorescence.
    6. 6
      Hirata, S. Recent Advances in Materials with Room-Temperature Phosphorescence: Photophysics for Triplet Exciton Stabilization. Adv. Opt. Mater. 2017, 5 (17), 1700116,  DOI: 10.1002/adom.201700116
      There is no corresponding record for this reference.
    7. 7
      Zhou, Q.; Wang, Z.; Dou, X.; Wang, Y.; Liu, S.; Zhang, Y.; Yuan, W. Z. Emission mechanism understanding and tunable persistent room temperature phosphorescence of amorphous nonaromatic polymers. Mater. Chem. Front. 2019, 3 (2), 257– 264,  DOI: 10.1039/C8QM00528A
      7
      Emission mechanism understanding and tunable persistent room temperature phosphorescence of amorphous nonaromatic polymers
      Zhou, Qing; Wang, Ziyi; Dou, Xueyu; Wang, Yunzhong; Liu, Saier; Zhang, Yongming; Yuan, Wang Zhang
      Materials Chemistry Frontiers (2019), 3 (2), 257-264CODEN: MCFAC5; ISSN:2052-1537. (Royal Society of Chemistry)
      Deciphering the emission mechanism of nonconventional luminogens and achieving persistent room temp. phosphorescence (p-RTP) from pure org. compds. have drawn increasing attention due to their significant fundamental importance and promising applications. Previous reports on nonconventional luminogens, however, mainly focus on fluorescence, while advances in pure org. p-RTP are generally restricted to arom. crystals or host-guest systems. Herein, we report the unique intrinsic emission and moreover p-RTP in amorphous nonarom. polymers of poly(acrylic acid) (PAA), polyacrylamide (PAM) and poly(N-isopropylacrylamide) (PNIPAM). These polymers are nonluminescent in dil. solns., while being highly emissive in concd. solns., nanosuspensions and solid powders/films. This can be rationalized by the clustering-triggered emission (CTE) mechanism, as supported by further thermoresponsive emission, cryogenic and aggregation-induced emission (AIE) expts., alongside single crystal anal. Furthermore, PAA and PAM solids under ambient conditions, and PNIPAM solids under vacuum or under nitrogen, demonstrate distinct p-RTP, which can be enhanced through further ionization or pressurization. These results not only refresh our understanding of the emission mechanism of nonarom. polymers, but also enable the facile fabrication and application of pure org. p-RTP luminogens from readily available compds., thus providing an important step forward in both nonconventional luminogens and p-RTP.
    8. 8
      Lee, D.; Bolton, O.; Kim, B. C.; Youk, J. H.; Takayama, S.; Kim, J. Room Temperature Phosphorescence of Metal-Free Organic Materials in Amorphous Polymer Matrices. J. Am. Chem. Soc. 2013, 135 (16), 6325– 6329,  DOI: 10.1021/ja401769g
      8
      Room Temperature Phosphorescence of Metal-Free Organic Materials in Amorphous Polymer Matrices
      Lee, Dongwook; Bolton, Onas; Kim, Byoung Choul; Youk, Ji Ho; Takayama, Shuichi; Kim, Jinsang
      Journal of the American Chemical Society (2013), 135 (16), 6325-6329CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)
      Developing metal-free org. phosphorescent materials is promising but challenging because achieving emissive triplet relaxation that outcompetes the vibrational loss of triplets, a key process to achieving phosphorescence, is difficult without heavy metal atoms. While recent studies reveal that bright room temp. phosphorescence can be realized in purely org. cryst. materials through directed halogen bonding, these org. phosphors still have limitations to practical applications due to the stringent requirement of high quality crystal formation. Here we report bright room temp. phosphorescence by embedding a purely org. phosphor into an amorphous glassy polymer matrix. Our study implies that the reduced beta (β)-relaxation of isotactic PMMA most efficiently suppresses vibrational triplet decay and allows the embedded org. phosphors to achieve a bright 7.5% phosphorescence quantum yield. We also demonstrate a microfluidic device integrated with a novel temp. sensor based on the metal-free purely org. phosphors in the temp.-sensitive polymer matrix. This unique system has many advantages: (i) simple device structures without feeding addnl. temp. sensing agents, (ii) bright phosphorescence emission, (iii) a reversible thermal response, and (iv) tunable temp. sensing ranges by using different polymers.
    9. 9
      Louis, M.; Thomas, H.; Gmelch, M.; Haft, A.; Fries, F.; Reineke, S. Blue-Light-Absorbing Thin Films Showing Ultralong Room-Temperature Phosphorescence. Adv. Mater. 2019, 31 (12), 1807887,  DOI: 10.1002/adma.201807887
      There is no corresponding record for this reference.
    10. 10
      Su, Y.; Phua, S. Z. F.; Li, Y.; Zhou, X.; Jana, D.; Liu, G.; Lim, W. Q.; Ong, W. K.; Yang, C.; Zhao, Y. Ultralong room temperature phosphorescence from amorphous organic materials toward confidential information encryption and decryption. Sci. Adv. 2018, 4 (5), eaas9732  DOI: 10.1126/sciadv.aas9732
      There is no corresponding record for this reference.
    11. 11
      Li, Q.; Zhou, M.; Yang, M.; Yang, Q.; Zhang, Z.; Shi, J. Induction of long-lived room temperature phosphorescence of carbon dots by water in hydrogen-bonded matrices. Nat. Commun. 2018, 9 (1), 734,  DOI: 10.1038/s41467-018-03144-9
      11
      Induction of long-lived room temperature phosphorescence of carbon dots by water in hydrogen-bonded matrices
      Li Qijun; Zhou Ming; Yang Mingyang; Yang Qingfeng; Zhang Zhixun; Shi Jing
      Nature communications (2018), 9 (1), 734 ISSN:.
      Phosphorescence shows great potential for application in bioimaging and ion detection because of its long-lived luminescence and high signal-to-noise ratio, but establishing phosphorescence emission in aqueous environments remains a challenge. Herein, we present a general design strategy that effectively promotes phosphorescence by utilising water molecules to construct hydrogen-bonded networks between carbon dots (CDs) and cyanuric acid (CA). Interestingly, water molecules not only cause no phosphorescence quenching but also greatly enhance the phosphorescence emission. This enhancement behaviour can be explained by the fact that the highly ordered bound water on the CA particle surface can construct robust bridge-like hydrogen-bonded networks between the CDs and CA, which not only effectively rigidifies the C=O bonds of the CDs but also greatly enhances the rigidity of the entire system. In addition, the CD-CA suspension exhibits a high phosphorescence lifetime (687 ms) and is successfully applied in ion detection based on its visible phosphorescence.
    12. 12
      Xu, S.; Evans, R. E.; Liu, T.; Zhang, G.; Demas, J. N.; Trindle, C. O.; Fraser, C. L. Aromatic Difluoroboron β-Diketonate Complexes: Effects of π-Conjugation and Media on Optical Properties. Inorg. Chem. 2013, 52 (7), 3597– 3610,  DOI: 10.1021/ic300077g
      12
      Aromatic Difluoroboron β-Diketonate Complexes: Effects of π-Conjugation and Media on Optical Properties
      Xu, Songpan; Evans, Ruffin E.; Liu, Tiandong; Zhang, Guoqing; Demas, J. N.; Trindle, Carl O.; Fraser, Cassandra L.
      Inorganic Chemistry (2013), 52 (7), 3597-3610CODEN: INOCAJ; ISSN:0020-1669. (American Chemical Society)
      Arom. difluoroboron β-diketonate complexes (BF2bdks) are classic fluorescent mols. that were explored as photochem. reagents, two-photon dyes, and O sensors. To gain a better understanding of their emissive properties in both soln. and polymer matrixes, BF2bdks with varying arom. groups were synthesized and their photophys. properties were studied in both CH2Cl2 and poly(lactic acid) (PLA). Absorption spectra showed systematic variations that are well correlated with structural features, including the size of the aryl substituent and the presence of a para electron-donating methoxy substituent. Computational modeling of the absorption spectra with the TD-B3LYP/6-311+G(d)//B3LYP/6-31G(d) formulation of d. functional theory and a polarizable continuum model of CH2Cl2 solvent shows that all systems show intense π-π* 1-electron excitations, usually from one of the highest occupied MOs (HOMO - k, k = 0, 1, 2) to the LUMO. Emission properties are sensitive to the dye structure and medium. Based on spectroscopic and lifetime studies, BF2bdks exhibit comparable fluorescence properties in both solns. and polymers when the diketonate group is functionalized with smaller arom. ring systems such as benzene. For BF2bdks with larger arene ring systems, such as anthracene, emission from a strong intramol. charge-transfer (ICT) state was also noted in both soln. and in PLA. There are differences in relative intensities of peaks arising from π-π* and ICT excitations depending upon dye loading in PLA. Substituent effects were also obsd. Electron-donating methoxyl groups on the arom. rings lead to enhanced fluorescence quantum yields. For certain dyes, phosphorescence is detected at low temp. or under a N atm. in PLA matrixes.
    13. 13
      Daly, M. L.; Kerr, C.; DeRosa, C. A.; Fraser, C. L. Meta-Alkoxy-Substituted Difluoroboron Dibenzoylmethane Complexes as Environment-Sensitive Materials. ACS Appl. Mater. Interfaces 2017, 9 (37), 32008– 32017,  DOI: 10.1021/acsami.7b06910
      13
      Meta-Alkoxy-Substituted Difluoroboron Dibenzoylmethane Complexes as Environment-Sensitive Materials
      Daly, Margaret L.; Kerr, Caroline; DeRosa, Christopher A.; Fraser, Cassandra L.
      ACS Applied Materials & Interfaces (2017), 9 (37), 32008-32017CODEN: AAMICK; ISSN:1944-8244. (American Chemical Society)
      The optical properties of meta-alkoxy-substituted difluoroboron dibenzoylmethane dyes were investigated in soln. and in the solid state. Meta-alkoxy substitution induced strong intramol. charge transfer (ICT) from the oxygen-donating substituent to the halide and boron acceptors in the excited state, as compared to the π-π* transition that is obsd. with para-alkoxy substitution. The optical properties of para- and meta-substituted alkoxy boron dyes were evaluated by calcns., in dil. soln., and in solid-state films. When embedded in amorphous matrixes (e.g., PLA, PMMA, PS, cholesterol), all dyes showed fluorescence (F) and phosphorescence (P) emission. In this report, we show that meta-substitution resulted in enhanced solvatochromism and an increased phosphorescence-to-fluorescence ratio in solid-state films compared to analogous para-substituted samples. With enhanced phosphorescence intensity via the heavy-atom effect, iodo-substituted dyes were further studied in PLA-PEG nanoparticles. Oxygen calibrations revealed stronger phosphorescence and a greater oxygen-sensing range for the meta- vs. para-alkoxy-substituted dyes, features that are important for oxygen-sensing materials design.
    14. 14
      Kwon, M. S.; Yu, Y.; Coburn, C.; Phillips, A. W.; Chung, K.; Shanker, A.; Jung, J.; Kim, G.; Pipe, K.; Forrest, S. R.; Youk, J. H.; Gierschner, J.; Kim, J. Suppressing molecular motions for enhanced room-temperature phosphorescence of metal-free organic materials. Nat. Commun. 2015, 6, 8947,  DOI: 10.1038/ncomms9947
      14
      Suppressing molecular motions for enhanced room-temperature phosphorescence of metal-free organic materials
      Kwon, Min Sang; Yu, Youngchang; Coburn, Caleb; Phillips, Andrew W.; Chung, Kyeongwoon; Shanker, Apoorv; Jung, Jaehun; Kim, Gunho; Pipe, Kevin; Forrest, Stephen R.; Youk, Ji Ho; Gierschner, Johannes; Kim, Jinsang
      Nature Communications (2015), 6 (), 8947pp.CODEN: NCAOBW; ISSN:2041-1723. (Nature Publishing Group)
      Metal-free org. phosphorescent materials are attractive alternatives to the predominantly used organometallic phosphors but are generally dimmer and are relatively rare, as, without heavy-metal atoms, spin-orbit coupling is less efficient and phosphorescence usually cannot compete with radiationless relaxation processes. Here we present a general design rule and a method to effectively reduce radiationless transitions and hence greatly enhance phosphorescence efficiency of metal-free org. materials in a variety of amorphous polymer matrixes, based on the restriction of mol. motions in the proximity of embedded phosphors. Covalent crosslinking between phosphors and polymer matrixes via Diels-Alder click chem. is devised as a method. A sharp increase in phosphorescence quantum efficiency is obsd. in a variety of polymer matrixes with this method, which is ca. two to five times higher than that of phosphor-doped polymer systems having no such covalent linkage.
    15. 15
      Tao, S.; Lu, S.; Geng, Y.; Zhu, S.; Redfern, S. A. T.; Song, Y.; Feng, T.; Xu, W.; Yang, B. Design of Metal-Free Polymer Carbon Dots: A New Class of Room-Temperature Phosphorescent Materials. Angew. Chem., Int. Ed. 2018, 57 (9), 2393– 2398,  DOI: 10.1002/anie.201712662
      15
      Design of Metal-Free Polymer Carbon Dots: A New Class of Room-Temperature Phosphorescent Materials
      Tao, Songyuan; Lu, Siyu; Geng, Yijia; Zhu, Shoujun; Redfern, Simon A. T.; Song, Yubin; Feng, Tanglue; Xu, Weiqing; Yang, Bai
      Angewandte Chemie, International Edition (2018), 57 (9), 2393-2398CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)
      Polymer carbon dots (PCDs) are proposed as a new class of room-temp. phosphorescence (RTP) materials. The abundant energy levels in PCDs increase the probability of intersystem crossing (ISC) and their covalently crosslinked framework structures greatly suppress the nonradiative transitions. The efficient methods allow the manuf. of PCDs with unique RTP properties in air without addnl. metal complexation or complicated matrix compn. They thus provide a route towards the rational design of metal-free RTP materials that may be synthesized easily. Furthermore, we find that RTP is assocd. with a crosslink-enhanced emission (CEE) effect, which provides further routes to design improved PCDs with diverse RTP performance. Our results show the potential of PCDs as a universal route to achieve effective metal-free RTP.
    16. 16
      Ogoshi, T.; Tsuchida, H.; Kakuta, T.; Yamagishi, T.-A.; Taema, A.; Ono, T.; Sugimoto, M.; Mizuno, M. Ultralong Room-Temperature Phosphorescence from Amorphous Polymer Poly(Styrene Sulfonic Acid) in Air in the Dry Solid State. Adv. Funct. Mater. 2018, 28 (16), 1707369,  DOI: 10.1002/adfm.201707369
      There is no corresponding record for this reference.
    17. 17
      Kanosue, K.; Ando, S. Polyimides with Heavy Halogens Exhibiting Room-Temperature Phosphorescence with Very Large Stokes Shifts. ACS Macro Lett. 2016, 5 (12), 1301– 1305,  DOI: 10.1021/acsmacrolett.6b00642
      17
      Polyimides with Heavy Halogens Exhibiting Room-Temperature Phosphorescence with Very Large Stokes Shifts
      Kanosue, Kenta; Ando, Shinji
      ACS Macro Letters (2016), 5 (12), 1301-1305CODEN: AMLCCD; ISSN:2161-1653. (American Chemical Society)
      Semiarom. polyimides (PIs) and imide compds. contg. heavy halogens (Br, I) in pyromellitic moieties were designed and synthesized to examine their photoluminescence properties. Solns. of imides and PI films exhibited reddish-color room-temp. phosphorescence (RTP) with very large Stokes shifts (ca. 10000 cm-1). In addn., the PI films showed small-Stokes-shifted fluorescence emissions at around 540 nm with absorption bands arising from aggregated PI chains at 400-500 nm. Enhanced phosphorescence obsd. for the PI films under vacuum indicates that the RTP lifetime is significantly influenced by the triplet-triplet energy transfer to atm. oxygen. These PIs with very-large-Stokes-shifted RTP are applicable as spectral conversion materials in displays, photovoltaic devices, and crop cultivators, as well as to oxygen/air sensors.
    18. 18
      Chen, H.; Ma, X.; Wu, S.; Tian, H. A Rapidly Self-Healing Supramolecular Polymer Hydrogel with Photostimulated Room-Temperature Phosphorescence Responsiveness. Angew. Chem., Int. Ed. 2014, 53 (51), 14149– 14152,  DOI: 10.1002/anie.201407402
      18
      A Rapidly Self-Healing Supramolecular Polymer Hydrogel with Photostimulated Room-Temperature Phosphorescence Responsiveness
      Chen, Hui; Ma, Xiang; Wu, Shuaifan; Tian, He
      Angewandte Chemie, International Edition (2014), 53 (51), 14149-14152CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)
      Development of self-healing and photostimulated luminescent supramol. polymeric materials is important for artificial soft materials. A supramol. polymeric hydrogel is reported based on the host-guest recognition between a β-cyclodextrin (β-CD) host polymer (poly-β-CD) and an α-bromonaphthalene (α-BrNp) polymer (poly-BrNp) without any addnl. gelator, which can self-heal within only about one minute under ambient atm. without any additive. This supramol. polymer system can be excited to engender room-temp. phosphorescence (RTP) signals based on the fact that the inclusion of β-CD macrocycle with α-BrNp moiety is able to induce RTP emission (CD-RTP). The RTP signal can be adjusted reversibly by competitive complexation of β-CD with azobenzene moiety under specific irradn. by introducing another azobenzene guest polymer (poly-Azo).
    19. 19
      Zhang, Y.-F.; Wang, Y.-C.; Yu, X.-S.; Zhao, Y.; Ren, X.-K.; Zhao, J.-F.; Wang, J.; Jiang, X.-Q.; Chang, W.-Y.; Zheng, J.-F.; Yu, Z.-Q.; Yang, S.; Chen, E.-Q. Isophthalate-Based Room Temperature Phosphorescence: From Small Molecule to Side-Chain Jacketed Liquid Crystalline Polymer. Macromolecules 2019, 52 (6), 2495– 2503,  DOI: 10.1021/acs.macromol.9b00171
      19
      Isophthalate-Based Room Temperature Phosphorescence: From Small Molecule to Side-Chain Jacketed Liquid Crystalline Polymer
      Zhang, Yan-Fang; Wang, Yue-Chao; Yu, Xiao-Song; Zhao, Yang; Ren, Xiang-Kui; Zhao, Jian-Feng; Wang, Jun; Jiang, Xu-Qiang; Chang, Wen-Ying; Zheng, Jun-Feng; Yu, Zhen-Qiang; Yang, Shuang; Chen, Er-Qiang
      Macromolecules (Washington, DC, United States) (2019), 52 (6), 2495-2503CODEN: MAMOBX; ISSN:0024-9297. (American Chemical Society)
      Isophthalate with the simple chem. structure is identified as an effective phosphor for room temp. phosphorescent (RTP) materials. With -Br, -CH3, and -CH=CH2 at the 5-position of the benzene ring of didecyl isophthalate, the three cryst. small mols. of DDIP-Br, DDIP-CH3, and DDIP-CH=CH2 demonstrate ultralong RTP with lifetime of 236, 650, and 184 ms, resp., although no specific interactions are recognized in the crystals. Radical polymn. of DDIP-CH=CH2 readily results in Poly-1, which is the first RTP liq. cryst. polymer. Direct attachment of isophthalate phosphor to every repeating unit of polyethylene backbone through a single carbon-carbon bond leads to a significant side-chain jacketing effect, greatly reducing the motion of phosphor moieties. Poly-1 renders a columnar LC phase constructed by parallel packing of the supramol. column that is composed of two Poly-1 chains. In the column, the isophthalate phosphor is confined in between the core of polymer backbones and the shell of decyl tails, and thus the nonradiative process is further suppressed. The materials design of Poly-1 can be widely applied for developing new RTP polymers.
    20. 20
      Yu, Y.; Kwon, M. S.; Jung, J.; Zeng, Y.; Kim, M.; Chung, K.; Gierschner, J.; Youk, J. H.; Borisov, S. M.; Kim, J. Room-Temperature-Phosphorescence-Based Dissolved Oxygen Detection by Core-Shell Polymer Nanoparticles Containing Metal-Free Organic Phosphors. Angew. Chem., Int. Ed. 2017, 56 (51), 16207– 16211,  DOI: 10.1002/anie.201708606
      20
      Room-Temperature-Phosphorescence-Based Dissolved Oxygen Detection by Core-Shell Polymer Nanoparticles Containing Metal-Free Organic Phosphors
      Yu, Youngchang; Kwon, Min Sang; Jung, Jaehun; Zeng, Yingying; Kim, Mounggon; Chung, Kyeongwoon; Gierschner, Johannes; Youk, Ji Ho; Borisov, Sergey M.; Kim, Jinsang
      Angewandte Chemie, International Edition (2017), 56 (51), 16207-16211CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)
      The highly sensitive optical detection of O including dissolved O (DO) is of great interest in various applications. We devised a novel room-temp.-phosphorescence (RTP)-based O detection platform by constructing core-shell nanoparticles with water-sol. polymethyloxazoline shells and O-permeable polystyrene cores crosslinked with metal-free purely org. phosphors. The resulting nanoparticles show a very high sensitivity for DO with a limit of detection (LOD) of 60nM and can be readily used for O quantification in aq. environments as well as the gaseous phase.
    21. 21
      Wang, X.-F.; Xiao, H.; Chen, P.-Z.; Yang, Q.-Z.; Chen, B.; Tung, C.-H.; Chen, Y.-Z.; Wu, L.-Z. Pure Organic Room Temperature Phosphorescence from Excited Dimers in Self-Assembled Nanoparticles under Visible and Near-Infrared Irradiation in Water. J. Am. Chem. Soc. 2019, 141 (12), 5045– 5050,  DOI: 10.1021/jacs.9b00859
      21
      Pure Organic Room Temperature Phosphorescence from Excited Dimers in Self-Assembled Nanoparticles under Visible and Near-Infrared Irradiation in Water
      Wang, Xiao-Fang; Xiao, Hongyan; Chen, Peng-Zhong; Yang, Qing-Zheng; Chen, Bin; Tung, Chen-Ho; Chen, Yu-Zhe; Wu, Li-Zhu
      Journal of the American Chemical Society (2019), 141 (12), 5045-5050CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)
      Pure org. room temp. phosphorescence (RTP) has unique advantages and various potential applications. However, it is challengeable to achieve org. RTP under visible and near-IR (NIR)-light excitation, esp. in aq. soln. Herein the authors assemble difluoroboron β-diketonate compds. to form org. nanoparticles (NPs) in water. The resulting NPs are able to show efficient RTP, effective uptake, and bright imaging of HeLa cells under both visible- and NIR-light excitation. More strikingly, spectroscopic study, single-crystal x-ray diffraction, and DFT calcn. reveal that the efficient RTP in org. NPs is originated from dimers in their excited states. The multiple interactions and intermol. charge transfer in the dimer structures are of significance in promoting the prodn. of dimer triplet excited states and suppressing the nonradiative decays to boost the RTP under visible- and NIR-light irradn. in water.
    22. 22
      Wang, D.; Wang, X.; Xu, C.; Ma, X. A novel metal-free amorphous room-temperature phosphorescent polymer without conjugation. Sci. China: Chem. 2019, 62 (4), 430– 433,  DOI: 10.1007/s11426-018-9383-2
      22
      A novel metal-free amorphous room-temperature phosphorescent polymer without conjugation
      Wang, Disen; Wang, Xi; Xu, Chao; Ma, Xiang
      Science China: Chemistry (2019), 62 (4), 430-433CODEN: SCCCCS; ISSN:1869-1870. (Science China Press)
      Room-temp. phosphorescence (RTP) has attracted much attention due to its potential applications in the fields of biol. imaging, chem. sensors and so forth. Particularly, amorphous metal-free RTP materials show special advantages of low cost and good processability. In addn., non-conjugated polymers have seldom been reported as phosphorescent materials. In this work, a novel non-conjugated amorphous metal-free copolymer composed of brominated olefins and acrylamide was prepd. in a facile way, which could engender blue-purple RTP emission. Polymers with different kinds of brominated olefins and different ratios of two monomers have been investigated with the purpose of researching the compn./property relationship that may affect the RTP properties. This unique phenomenon could be due to the clustering of carbonyl and amino units caused mol. interaction, and the heavy-atom effect enhanced intersystem crossing. Meantime, the hydrogen bonding in the system enhanced the conformation rigidification to reduce the non-radiative decay. This work provided a delicate way to construct non-conjugated metal-free RTP materials and supplied a new insight into the development of RTP materials.
    23. 23
      Zhang, T.; Chen, H.; Ma, X.; Tian, H. Amorphous 2-Bromocarbazole Copolymers with Efficient Room-Temperature Phosphorescent Emission and Applications as Encryption Ink. Ind. Eng. Chem. Res. 2017, 56 (11), 3123– 3128,  DOI: 10.1021/acs.iecr.7b00149
      23
      Amorphous 2-Bromocarbazole Copolymers with Efficient Room-Temperature Phosphorescent Emission and Applications as Encryption Ink
      Zhang, Ting; Chen, Hui; Ma, Xiang; Tian, He
      Industrial & Engineering Chemistry Research (2017), 56 (11), 3123-3128CODEN: IECRED; ISSN:0888-5885. (American Chemical Society)
      The development of metal-free org. room-temp. phosphorescent (RTP) materials is promising but challenging, because spin-orbit coupling is less efficient without heavy metals such as platinum and palladium. Here, we present a novel amorphous copolymer composed of 2-bromocarbazole phosphor and acrylamide on its side chains, which can engender blue-purple phosphorescence emission with high quantum yield at room temp. The polymer matrixes of acrylamide and the hydrogen bonding in the polymeric chain system can effectively help to inhibit nonradiative transition process and, hence, strengthen the phosphorescent emission. The molar ratio of the 2-bromocarbazole phosphor and acrylamide remarkably influences the RTP emission intensities and quantum yields of the polymers. The high amt. of phosphor will weaken the rigidity of the polymers and the shielding effect from oxygen, thus leading to a decrease in their RTP emission, while a low concn. of the phosphor will also weaken their RTP emission intensity. Furthermore, RTP intensity of the amorphous polymer is responsive to humidity, because the hydrogen bonding in the polymeric chain system can be broken by water, which makes it applicable in the area of encryption.
    24. 24
      Zhao, Q.; Li, F.; Huang, C. Phosphorescent chemosensors based on heavy-metal complexes. Chem. Soc. Rev. 2010, 39 (8), 3007– 3030,  DOI: 10.1039/b915340c
      24
      Phosphorescent chemosensors based on heavy-metal complexes
      Zhao, Qiang; Li, Fuyou; Huang, Chunhui
      Chemical Society Reviews (2010), 39 (8), 3007-3030CODEN: CSRVBR; ISSN:0306-0012. (Royal Society of Chemistry)
      A review. Recently, the use of phosphorescent heavy-metal complexes as chemosensors has attracted increasing interest due to their advantageous photophys. properties. This crit. review focuses on the design principles and the recent development of phosphorescent chemosensors for metal cations, anions, pH, oxygen, volatile org. compds. and biomols. based on some heavy-metal complexes (such as Pt(II)-, Ru(II)-, Re(I)-, Ir(III)-, Cu(I)-, Au(I)- and Os(II)-based complexes), in which the variation in phosphorescence signals induced by the interaction between heavy-metal complexes and analytes is used (217 refs.).
    25. 25
      Ravotto, L.; Ceroni, P. Aggregation induced phosphorescence of metal complexes: From principles to applications. Coord. Chem. Rev. 2017, 346, 62– 76,  DOI: 10.1016/j.ccr.2017.01.006
      25
      Aggregation induced phosphorescence of metal complexes: From principles to applications
      Ravotto, Luca; Ceroni, Paola
      Coordination Chemistry Reviews (2017), 346 (), 62-76CODEN: CCHRAM; ISSN:0010-8545. (Elsevier B.V.)
      Metal complexes are the prototypes of phosphorescent materials, widely used in a range of optoelectronic and sensing applications. This review reports the most recent and tutorial results in the area of aggregation induced phosphorescence (AIP) of metal complexes, i.e. mols. that are weakly or non-phosphorescent in deaerated fluid soln. and whose room temp. phosphorescence is switched on upon aggregation. The examples are divided into two main classes according to the AIP mechanism: (i) rigidification that causes a restriction of intramol. motions as well as of structural distortion of the phosphorescent excited state and (ii) metallophilic interaction that brings about new electronic transitions compared to the isolated chromophores. The last section is devoted to a special class of mols. and supramol. systems, in which metal complexation turns on phosphorescence of nearby org. chromophores, so that the metal complex is not directly involved in the phosphorescence process.
    26. 26
      Yang, Y.; Wang, K.-Z.; Yan, D. Ultralong Persistent Room Temperature Phosphorescence of Metal Coordination Polymers Exhibiting Reversible pH-Responsive Emission. ACS Appl. Mater. Interfaces 2016, 8 (24), 15489– 15496,  DOI: 10.1021/acsami.6b03956
      26
      Ultralong Persistent Room Temperature Phosphorescence of Metal Coordination Polymers Exhibiting Reversible pH-Responsive Emission
      Yang, Yongsheng; Wang, Ke-Zhi; Yan, Dongpeng
      ACS Applied Materials & Interfaces (2016), 8 (24), 15489-15496CODEN: AAMICK; ISSN:1944-8244. (American Chemical Society)
      Ultra-long-persistent room temp. phosphorescence (RTP) materials have attracted much attention and present various applications in illumination, displays, and the bioimaging field; the persistent RTP is generally from the inorg. phosphor materials to date. The metal coordination polymers (CPs) could be new types of emerging long-lived RTP materials for potential sensor applications. First, 2 kinds of Cd-based CPs, Cd(m-BDC)(H2O) (1) and Cd(m-BDC)(BIM) (2) (m-BDC = 1,3-benzenedicarboxylic acid; BIM = benzimidazole), were obtained through a hydrothermal process, and the samples exhibit 2-dimensional layered structures, which are stabilized by interlayer C-H···π interaction and π···π interaction, resp. The CPs show unexpected 2nd-time-scale ultra-long-persistent RTP after the removal of UV excitation, and this persistent emission can be detected easily on a time scale of 0-10 s. The CPs also feature a tunable luminescence decay lifetime by adjusting their coordination situation and packing fashion of ligands. Theor. calcn. further indicates that the introduction of the 2nd ligand could highly influence the electronic structure and intermol. electron transfer toward tailoring the RTP of the CP materials. CP 2 exhibits well-defined pH- and temp.-dependent phosphorescence responses. Therefore, this work provides a facile way to develop new type of CPs with steady-state and dynamic tuning of the RTP properties from both exptl. and theor. perspectives, which have potential applications in the areas of displays, pH/temp. sensors, and phosphorescence logic gates. On account of suitable incorporation of inorg. and org. building blocks, it can be expected that the ultra-long-persistent RTP CPs can be extended to other similar systems due to the highly tunable structures and facile synthesis routes.
    27. 27
      Yan, Q.; Fan, Y.; Zhao, D. Unusual Temperature-Dependent Photophysics of Oligofluorene-Substituted Tris-Cyclometalated Iridium Complexes. Macromolecules 2012, 45 (1), 133– 141,  DOI: 10.1021/ma2024123
      27
      Unusual Temperature-Dependent Photophysics of Oligofluorene-Substituted Tris-Cyclometalated Iridium Complexes
      Yan, Qifan; Fan, Yuanpeng; Zhao, Dahui
      Macromolecules (Washington, DC, United States) (2012), 45 (1), 133-141CODEN: MAMOBX; ISSN:0024-9297. (American Chemical Society)
      The photophys. properties of a series of tris-cyclometalated Ir(III) complexes bearing oligofluorene-substituted 2-phenylpyridine (ppy) and/or 1-phenylisoquinoline (piq) ligands were studied at both room temp. and 77 K, for delineating the oligomer-substitution effects on the photophysics in such metal-complex-contg. conjugated oligomers/polymers. Unique temp. dependence was obsd. with the triplet excited-state lifetime of the studied oligomers. Mols. having one of the three ppy ligands substituted with an oligofluorenyl group at varied positions exhibited two distinct types of phosphorescing behaviors. When the oligofluorene group was coupled to ppy in a conjugative fashion (i.e., at 5- or 4'- position), the complexes appeared to emit from a 3MLCT-dominated state perturbed by LC transition, as evidenced by the relatively short lifetimes of phosphorescence as well as hypsochromic shift upon lowering the temp. Surprisingly, even shorter triplet lifetimes were detected at 77 K for such oligomers. When the oligofluorenyl was tethered to the Ph ring of ppy meta to pyridine, emission properties were consistent with a 3LC-dominated state, mixed with a certain MLCT component. Uniquely, for these oligomers an evident bathochromic shift of emission with a significantly retarded radiative decay rate was obsd. at 77 K. Furthermore, when a piq ligand was incorporated, red phosphorescence characteristic of Ir-piq-based 3MLCT transition emerged, disregarding the substation position of the oligofluorene. All these different photophys. behaviors, particularly their unique temp. dependence, were explained by considering an energy transfer process between different triplet states, with dominant MLCT and LC characteristics. In complexes having all ppy-derived ligands, these two states were of similar but different energy. While one played a more important role than the other, both were contributing to the phosphorescence emission. The temp. dependence of the photophysics reflected the equil. shifting process. When the 3MLCT-dominated state was lower in energy, faster radiative decay and shorter lifetimes were manifested upon lowering the temp., as a result of more favored 3MLCT-dominated state. Whereas if the 3LC-dominated state was more stable, slower radiative decay emerged at decreased temp. due to further a reduced MLCT contribution. The bathochromic shift was also a result of equil. shifting to the state of lower energy. When the piq ligand was engaged, the emission was governed by the 3MLCT state of the Ir-piq moiety, which had much lower energy compared to the triplet states localized in oligofluorenyl ppy. DFT calcns. substantiated the above hypothesis by identifying sep. MOs possessing mixed but imbalanced MLCT and LC components.
    28. 28
      Schubert, D. M. Boron: inorganic chemistry. Encyclopedia of Inorganic and Bioinorganic Chemistry 2015, 1– 28,  DOI: 10.1002/9781119951438.eibc0024.pub2
      28
      Boron: inorganic chemistry
      Schubert, David M.
      Encyclopedia of Inorganic and Bioinorganic Chemistry (2015), (), 1-28CODEN: 69UGQZ ISSN:. (John Wiley & Sons Ltd.)
      There is no expanded citation for this reference.
    29. 29
      Wu, Q.; Xiong, H.; Peng, Y.; Yang, Y.; Kang, J.; Huang, G.; Ren, X.; Wu, J. Highly Stretchable and Self-Healing “Solid-Liquid” Elastomer with Strain-Rate Sensing Capability. ACS Appl. Mater. Interfaces 2019, 11 (21), 19534– 19540,  DOI: 10.1021/acsami.9b05230
      29
      Highly Stretchable and Self-Healing "Solid-Liquid" Elastomer with Strain-Rate Sensing Capability
      Wu, Qi; Xiong, Hui; Peng, Yan; Yang, Yi; Kang, Jian; Huang, Guangsu; Ren, Xiancheng; Wu, Jinrong
      ACS Applied Materials & Interfaces (2019), 11 (21), 19534-19540CODEN: AAMICK; ISSN:1944-8244. (American Chemical Society)
      To mimic the velocity-sensitive ability of the human skin, we fabricate a class of "solid-liq." elastomers (SLEs) by interpenetrating polyborosiloxane (PBS) with polydimethylsiloxane (PDMS). PBS forms a dynamic network through boron/oxygen dative bonds, while PDMS is covalently crosslinked to form a permanent network. The permanent network affords a scaffold for the dynamic network, endowing SLEs with high elasticity and structural stability, thereby overcoming the inherent drawbacks such as fluidity and irreversible deformation of conventional solid-liq. materials. Meanwhile, the dissocn. and assocn. of the dynamic network is time-dependent. Thus, the modulus of SLEs varies with strain rates, and if the SLEs contain carbon nanotubes, their elec. cond. is also responsive to strain rates. This property can be utilized to fabricate skin-like sensors with the ability to distinguish different contact velocities. Moreover, the dynamic network can dissipate energy and be repaired, leading to the high stretchability and self-healing performance of SLEs.
    30. 30
      Wang, M.; Nudelman, F.; Matthes, R. R.; Shaver, M. P. Frustrated Lewis Pair Polymers as Responsive Self-Healing Gels. J. Am. Chem. Soc. 2017, 139 (40), 14232– 14236,  DOI: 10.1021/jacs.7b07725
      30
      Frustrated Lewis Pair Polymers as Responsive Self-Healing Gels
      Wang, Meng; Nudelman, Fabio; Matthes, Rebecca R.; Shaver, Michael P.
      Journal of the American Chemical Society (2017), 139 (40), 14232-14236CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)
      Steric bulk prevents the formation of strong bonds between Lewis acids and bases in frustrated Lewis pairs (FLPs), where latent reactivity makes these reagents transformative in small mol. activations and metal-free catalysis. However, their use as a platform for developing materials chem. is unexplored. Here we report a fully macromol. FLP, built from linear copolymers that contg. either a sterically encumbered Lewis base or Lewis acid as a pendant functional group. The target functional copolymers were prepd. by a controlled radical copolymn. of styrene with designer boron or phosphorus contg. monomers. Mixts. of the B- and P-functionalized polystyrenes do not react, with the steric bulk of the functional monomers preventing the favorable Lewis acid base interaction. Addn. of a small mol. (di-Et azodicarboxylate) promotes rapid network formation, crosslinking the reactive polymer chains. The resulting gel is dynamic, can self-heal, is heat responsive, and can be reshaped by postgelation processing.
    31. 31
      Icli, B.; Sheepwash, E.; Riis-Johannessen, T.; Schenk, K.; Filinchuk, Y.; Scopelliti, R.; Severin, K. Dative boron-nitrogen bonds in structural supramolecular chemistry: multicomponent assembly of prismatic organic cages. Chem. Sci. 2011, 2 (9), 1719– 1721,  DOI: 10.1039/c1sc00320h
      31
      Dative boron-nitrogen bonds in structural supramolecular chemistry: multicomponent assembly of prismatic organic cages
      Icli, Burcak; Sheepwash, Erin; Riis-Johannessen, Thomas; Schenk, Kurt; Filinchuk, Yaroslav; Scopelliti, Rosario; Severin, Kay
      Chemical Science (2011), 2 (9), 1719-1721CODEN: CSHCCN; ISSN:2041-6520. (Royal Society of Chemistry)
      The multicomponent reaction of diboronic acids with a catechol and a tripyridyl linker results in the formation trigonal prismatic cages. The cages feature 6 dative B-N bonds as structure-directing elements. The size of the cages can be varied by changing the diboronic acid building block. The cages are able to encapsulate polyarom. mols. such as triphenylene or coronene.
    32. 32
      Beuerle, F.; Gole, B. Covalent Organic Frameworks and Cage Compounds: Design and Applications of Polymeric and Discrete Organic Scaffolds. Angew. Chem., Int. Ed. 2018, 57 (18), 4850– 4878,  DOI: 10.1002/anie.201710190
      32
      Covalent Organic Frameworks and Cage Compounds: Design and Applications of Polymeric and Discrete Organic Scaffolds
      Beuerle, Florian; Gole, Bappaditya
      Angewandte Chemie, International Edition (2018), 57 (18), 4850-4878CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)
      A review. Porous org. materials are an emerging class of functional nanostructures with unprecedented properties. Dynamic covalent assembly of small org. building blocks under thermodn. control is utilized for the intriguingly simple formation of complex mol. architectures in one-pot procedures. In this Review, we aim to analyze the basic design principles that govern the formation of either covalent org. frameworks as cryst. porous polymers or covalent org. cage compds. as shape-persistent mol. objects. Common synthetic procedures and characterization techniques will be discussed and more advanced strategies such as postsynthetic modification or self-sorting. When appropriate, comparisons are drawn between polymeric frameworks and discrete org. cages in terms of their underlying properties. Furthermore, we highlight the potential of these materials for applications ranging from gas storage to catalysis and org. electronics.
    33. 33
      Sheepwash, E.; Krampl, V.; Scopelliti, R.; Sereda, O.; Neels, A.; Severin, K. Molecular Networks Based on Dative Boron-Nitrogen Bonds. Angew. Chem., Int. Ed. 2011, 50 (13), 3034– 3037,  DOI: 10.1002/anie.201007225
      33
      Molecular Networks Based on Dative Boron-Nitrogen Bonds
      Sheepwash, Erin; Krampl, Vincent; Scopelliti, Rosario; Sereda, Olha; Neels, Antonia; Severin, Kay
      Angewandte Chemie, International Edition (2011), 50 (13), 3034-3037, S3034/1-S3034/12CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)
      Cryst. polymers are prepd. by reaction of I (R = single bond), 4-tert-butylcatechol (II), and 4,4'-bipyridine (III) or 1,2-bis(4-pyridyl)ethylene 3 h in 2:1 Ph-THF mixt. at reflux, and gels are prepd. by reaction of I (R = p-C6H4) (IV), II, and III in PhMe. Alternatively, a gel was prepd. by reaction of IV with II, and reaction of the intermediate triboronate ester with III,. NMR showed that the gel formed at about 60° and a rupture of BN bonds occurred at 60-90°. The gel-sol transition was accompanied with a loss of orange color. The crystal structure was discussed for of the cryst. polymers.
    34. 34
      Stephens, A. J.; Scopelliti, R.; Tirani, F. F.; Solari, E.; Severin, K. Crystalline Polymers Based on Dative Boron-Nitrogen Bonds and the Quest for Porosity. ACS Mater. Lett. 2019, 1 (1), 3– 7,  DOI: 10.1021/acsmaterialslett.9b00054
      34
      Crystalline Polymers Based on Dative Boron-Nitrogen Bonds and the Quest for Porosity
      Stephens, Alexander J.; Scopelliti, Rosario; Tirani, Farzaneh Fadaei; Solari, Euro; Severin, Kay
      ACS Materials Letters (2019), 1 (1), 3-7CODEN: AMLCEF; ISSN:2639-4979. (American Chemical Society)
      Cryst. networks based on dative boron-nitrogen bonds were obtained by combining polytopic N-donor ligands with polyboronic esters. The use of a tetrahedral boronate ester gave rise to a sheet structure, whereas either a linear polymer or a diamond-like network was obsd. for a tetrahedral N-donor ligand. The intrinsic flexibility of B←N linkages favors tight intermol. packing and interpenetration in the cryst. state. Amorphous B←N networks, however, possess porosity with BET surface areas of up to ∼300 m2 g-1. These materials display processability in org. solvents, and hydrolytic damage can be repaired by simple heating-cooling cycles.
    35. 35
      Zhang, G.; Chen, J.; Payne, S. J.; Kooi, S. E.; Demas, J. N.; Fraser, C. L. Multi-Emissive Difluoroboron Dibenzoylmethane Polylactide Exhibiting Intense Fluorescence and Oxygen-Sensitive Room-Temperature Phosphorescence. J. Am. Chem. Soc. 2007, 129 (29), 8942– 8943,  DOI: 10.1021/ja0720255
      35
      Multi-Emissive Difluoroboron Dibenzoylmethane Polylactide Exhibiting Intense Fluorescence and Oxygen-Sensitive Room-Temperature Phosphorescence
      Zhang, Guoqing; Chen, Jianbin; Payne, Sarah J.; Kooi, Steven E.; Demas, J. N.; Fraser, Cassandra L.
      Journal of the American Chemical Society (2007), 129 (29), 8942-8943CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)
      Boron difluoride compds. are light emitting materials with impressive optical properties. Though their strong one- and two-photon absorption and intense fluorescence are well-known and exploited in mol. probes, lasers, and photosensitizers, phosphorescence, in contrast, is typically obsd. only at low temps. Here, the authors report that unusual room-temp. phosphorescence is achieved by combining a classic boron dye, difluoroboron dibenzoylmethane, BF2dbm, with poly(lactic acid) (PLA), a common biopolymer, resulting in a highly sensitive single-component oxygen sensor. Fluorescence quantum yields are enhanced, and temp.-sensitive delayed fluorescence is also obsd. Multi-emissive BF2dbmPLA biomaterials show great promise as multifunctional mol. probes and sensors.
    36. 36
      Zhang, G.; Evans, R. E.; Campbell, K. A.; Fraser, C. L. Role of Boron in the Polymer Chemistry and Photophysical Properties of Difluoroboron-Dibenzoylmethane Polylactide. Macromolecules 2009, 42 (22), 8627– 8633,  DOI: 10.1021/ma9019043
      36
      Role of Boron in the Polymer Chemistry and Photophysical Properties of Difluoroboron-Dibenzoylmethane Polylactide
      Zhang, Guoqing; Evans, Ruffin E.; Campbell, Kirsti A.; Fraser, Cassandra L.
      Macromolecules (Washington, DC, United States) (2009), 42 (22), 8627-8633CODEN: MAMOBX; ISSN:0024-9297. (American Chemical Society)
      Difluoroboron β-diketonate-polymer conjugates have remarkable solid-state luminescent properties that are useful in a variety of fields including multiphoton microscopy, cell biol., and tumor hypoxia imaging. Despite the successful applications of these systems, the role of B in these polymeric materials has not been thoroughly studied; a boron-free model system with dibenzoylmethane chromophores in poly(lactic acid) (PLA) was studied, for comparison. The hydroxyl-functionalized arom. diketone dibenzoylmethane (dbmOH), is weakly fluorescent in the solid state and nonfluorescent in soln. while its difluoroboron complex (BF2dbmOH) is highly emissive in both states. Using dbmOH and BF2dbmOH as initiators, well-defined end-functionalized polylactides, dbmPLA and BF2dbmPLA, were obtained via tin-catalyzed controlled ring-opening polymn. Boronation of the dbmOH initiator affects the polymn. kinetics and the photophys. properties of the resulting BF2dbmPLA material. Both dbmPLA and BF2dbmPLA are dual emissive in the solid state, exhibiting both fluorescence and room-temp. phosphorescence (RTP), whereas only BF2dbmPLA is luminescent in soln. These results suggest that B plays two roles: (1) as a protecting group in polymn. and (2) as emission enhancer. The presence of dual emission for both polymers indicates that it may be the diketone core structure rather than the difluoroboron that is essential for RTP in a rigid PLA matrix.
    37. 37
      Shoji, Y.; Ikabata, Y.; Wang, Q.; Nemoto, D.; Sakamoto, A.; Tanaka, N.; Seino, J.; Nakai, H.; Fukushima, T. Unveiling a New Aspect of Simple Arylboronic Esters: Long-Lived Room-Temperature Phosphorescence from Heavy-Atom-Free Molecules. J. Am. Chem. Soc. 2017, 139 (7), 2728– 2733,  DOI: 10.1021/jacs.6b11984
      37
      Unveiling a New Aspect of Simple Arylboronic Esters: Long-Lived Room-Temperature Phosphorescence from Heavy-Atom-Free Molecules
      Shoji, Yoshiaki; Ikabata, Yasuhiro; Wang, Qi; Nemoto, Daisuke; Sakamoto, Atsushi; Tanaka, Naoki; Seino, Junji; Nakai, Hiromi; Fukushima, Takanori
      Journal of the American Chemical Society (2017), 139 (7), 2728-2733CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)
      Arylboronic esters can be used as versatile reagents in org. synthesis, as represented by Suzuki-Miyaura cross-coupling. Here we report a serendipitous finding that simple arylboronic esters are phosphorescent in the solid state at room temp. with a lifetime on the order of several seconds. The phosphorescence properties of arylboronic esters are remarkable in light of the general notion that phosphorescent org. mols. require heavy atoms and/or carbonyl groups for the efficient generation of a triplet excited state. Theor. calcns. on phenylboronic acid pinacol ester indicated that this mol. undergoes an out-of-plane distortion at the (pinacol)B-Cipso moiety in the T1 excited state, which is responsible for its phosphorescence. A compd. survey with 19 arylboron compds. suggested that the phosphorescence properties might be detd. by solid-state mol. packing rather than by the patterns and nos. of boron substituents on the aryl units. The present finding may update the general notion of phosphorescent org. mols.
    38. 38
      Kuno, S.; Kanamori, T.; Yijing, Z.; Ohtani, H.; Yuasa, H. Long Persistent Phosphorescence of Crystalline Phenylboronic Acid Derivatives: Photophysics and a Mechanistic Study. ChemPhotoChem. 2017, 1 (3), 102– 106,  DOI: 10.1002/cptc.201600031
      38
      Long Persistent Phosphorescence of Crystalline Phenylboronic Acid Derivatives: Photophysics and a Mechanistic Study
      Kuno, Shinichi; Kanamori, Takashi; Yijing, Zhao; Ohtani, Hiroyuki; Yuasa, Hideya
      ChemPhotoChem (2017), 1 (3), 102-106CODEN: CHEMYH ISSN:. (Wiley-VCH Verlag GmbH & Co. KGaA)
      Room-temp. phosphorescence (RTP) of cryst. isophthalic acid (IPA) through hyperfine-coupling-driven (HFC-driven) intersystem crossing in charge-transfer (CT) complexes has been discovered recently, giving rise to a new design method for phosphorescence materials and photosensitizers. In this study, we found that cryst. phenylboronic acid (PB) derivs. also demonstrated RTP, as recorded for IPA. Magnetic-field and spin-isotope effects on the emission strength intensities of PBs were typical of HFC-driven phosphorescence. p-Halogenated PB esters exhibited a heavy-atom effect with a shortened emission lifetime as expected from the study of IPA. Unlike IPA, the esters of PBs also showed RTP, which facilitates a study of the structure/photophys. property relationships by exchanging ester head groups. We then addressed a question: do PB esters with a bulky head group prohibit CT formation and thus phosphorescence. As a result, a bulky PB ester with large intermol. distances in its cryst. form showed neither CT absorptions nor phosphorescence, confirming the significance of CT formation in the HFC mechanism.
    39. 39
      Chai, Z.; Wang, C.; Wang, J.; Liu, F.; Xie, Y.; Zhang, Y.-Z.; Li, J.-R.; Li, Q.; Li, Z. Abnormal room temperature phosphorescence of purely organic boron-containing compounds: the relationship between the emissive behaviorand the molecular packing, and the potential related applications. Chem. Sci. 2017, 8 (12), 8336– 8344,  DOI: 10.1039/C7SC04098A
      39
      Abnormal room temperature phosphorescence of purely organic boron-containing compounds: the relationship between the emissive behavior and the molecular packing, and the potential related applications
      Chai, Zhaofei; Wang, Can; Wang, Jinfeng; Liu, Fan; Xie, Yujun; Zhang, Yong-Zheng; Li, Jian-Rong; Li, Qianqian; Li, Zhen
      Chemical Science (2017), 8 (12), 8336-8344CODEN: CSHCCN; ISSN:2041-6520. (Royal Society of Chemistry)
      Purely org. materials with the characteristic of room-temp. phosphorescence (RTP) under ambient conditions demonstrate potential benefits in advanced optoelectronic applications. Exploration of versatile and efficient RTP compds. with low prices is full of challenges due to the slow intersystem crossing process and ultrafast deactivation of the active excited states of org. compds. Here, a series of boron-contg. phosphors were found to present RTP with long-lived lifetimes. Among these com. available and cheap compds., (4-methoxyphenyl)boronic acid (PBA-MeO) exhibits long-lived RTP, with a lifetime of 2.24 s, which is among the longest lifetimes of single-component small mols. Our extensive expts. illustrate that both a rigid conformation and expanded conjugation induced by mol. alignment contribute to the persistent RTP. Because of strong intermol. interactions via hydrogen bonds, these arylboronic acids easily form crystals and are quite appropriate for anti-forgery materials. Subsequently, we develop a precise, speedy and convenient inkjet printing technol. for the fabrication of optoelectronic displays. Furthermore, PBA-MeO is used as an additive to feed Bombyx mori silkworms and shows low toxicity over inorg. materials. Our findings may pave a new way for the development of RTP phosphors and promote their use in practical applications.
    40. 40
      Zhang, K.; Sun, Q.; Tang, L.; Wang, Y.; Fan, X.; Liu, L.; Xue, S.; Yang, W. Cyclic boron esterification: screening organic room temperature phosphorescent and mechanoluminescent materials. J. Mater. Chem. C 2018, 6 (32), 8733– 8737,  DOI: 10.1039/C8TC02938E
      40
      Cyclic boron esterification: screening organic room temperature phosphorescent and mechanoluminescent materials
      Zhang, Kai; Sun, Qikun; Tang, Liangliang; Wang, Yanhui; Fan, Xiaojing; Liu, Linxi; Xue, Shanfeng; Yang, Wenjun
      Journal of Materials Chemistry C: Materials for Optical and Electronic Devices (2018), 6 (32), 8733-8737CODEN: JMCCCX; ISSN:2050-7534. (Royal Society of Chemistry)
      Aryl boronic acids are a broad class of org. intermediates. Their cyclic-esterification with appropriate dihydric alcs. is a simple and effective approach for screening org. room-temp. phosphorescent (RTP) and mechanoluminescent (ML) materials. Non RTP and ML active 4-(carbazol-9-yl)phenylboronic acid can be made into long-lived RTP emitters with lifetimes of 264 and 430 ms and a bright ML dye with blue emission by cyclic-esterification with 1,3-propanediol, 2,2-dimethyl-1,3-propanediol, and glycol, resp. Systematic single crystal anal. and quantum chem. calcns. indicate that cyclic borates dominate the mol. packing structures and intermol. interactions, which is responsible for the different optical properties.
    41. 41
      Li, M.; Ling, K.; Shi, H.; Gan, N.; Song, L.; Cai, S.; Cheng, Z.; Gu, L.; Wang, X.; Ma, C.; Gu, M.; Wu, Q.; Bian, L.; Liu, M.; An, Z.; Ma, H.; Huang, W. Prolonging Ultralong Organic Phosphorescence Lifetime to 2.5 s through Confining Rotation in Molecular Rotor. Adv. Opt. Mater. 2019, 7 (10), 1800820,  DOI: 10.1002/adom.201800820
      There is no corresponding record for this reference.
    42. 42
      Nakahata, M.; Mori, S.; Takashima, Y.; Hashidzume, A.; Yamaguchi, H.; Harada, A. pH- and Sugar-Responsive Gel Assemblies Based on Boronate-Catechol Interactions. ACS Macro Lett. 2014, 3 (4), 337– 340,  DOI: 10.1021/mz500035w
      42
      pH- and Sugar-Responsive Gel Assemblies Based on Boronate-Catechol Interactions
      Nakahata, Masaki; Mori, Shoko; Takashima, Yoshinori; Hashidzume, Akihito; Yamaguchi, Hiroyasu; Harada, Akira
      ACS Macro Letters (2014), 3 (4), 337-340CODEN: AMLCCD; ISSN:2161-1653. (American Chemical Society)
      The interaction between poly(acrylamide) gels carrying phenylboronic acid (PB gel) and catechol moieties (CAT gel) resp. is studied. The PB gel forms an assembly with the CAT gel on a macroscopic scale in basic aq. media. The adhesion strength is estd. by stress-strain measurements. The assembly and disassembly of the gels are reversibly switched by varying the pH of the medium. The adhesion strength is tunable by competitive monosaccharide mols. in accordance with the assocn. const. with PB moieties.
    43. 43
      Smith, M. K.; Northrop, B. H. Vibrational Properties of Boroxine Anhydride and Boronate Ester Materials: Model Systems for the Diagnostic Characterization of Covalent Organic Frameworks. Chem. Mater. 2014, 26 (12), 3781– 3795,  DOI: 10.1021/cm5013679
      43
      Vibrational Properties of Boroxine Anhydride and Boronate Ester Materials: Model Systems for the Diagnostic Characterization of Covalent Organic Frameworks
      Smith, Merry K.; Northrop, Brian H.
      Chemistry of Materials (2014), 26 (12), 3781-3795CODEN: CMATEX; ISSN:0897-4756. (American Chemical Society)
      The vibrational characteristics of 28 different boronic acid, boroxine anhydride, and boronate ester species have been systematically investigated using a combination of exptl. IR spectroscopy and computational modeling. IR bands characteristic to each boron-contg. functionality have been categorized and assigned in conjunction with d. functional theory (B3LYP/6-31G(d)), with the aim of better understanding and distinguishing the vibrational characteristics of covalent org. frameworks (COFs) built from boronic acids. In several cases, vibrational assignments differ from those previously reported in the literature on boronic acid-based COFs. Vibrations commonly regarded as diagnostic for one functionality are found in regions of the IR spectrum where other functionalities also show characteristic peaks. The collective exptl. and computational results reveal that several alternative bands in the IR region can be used to more diagnostically distinguish between boronic acid, boroxine anhydride, and boronate ester species. The results presented herein provide the tools for straightforward characterization of boroxine anhydride and boronate ester species using IR spectroscopy. The results can be applied to addnl. theor. studies of larger COF-like assemblies as well as the anal. of other boronic-acid-based materials.
    44. 44
      Qin, Y.; Cui, C.; Jäkle, F. Silylated Initiators for the Efficient Preparation of Borane-End-Functionalized Polymers via ATRP. Macromolecules 2007, 40 (5), 1413– 1420,  DOI: 10.1021/ma061704h
      44
      Silylated Initiators for the Efficient Preparation of Borane-End-Functionalized Polymers via ATRP
      Qin, Yang; Cui, Chengzhong; Jaekle, Frieder
      Macromolecules (2007), 40 (5), 1413-1420CODEN: MAMOBX; ISSN:0024-9297. (American Chemical Society)
      Borane-end-functionalized polymers were prepd. through atom transfer radical polymn. (ATRP) of styrene using a silylated initiator, 1-bromo-1-(4-trimethylsilylphenyl)ethane (PEB-SiMe3). The SiMe3 end groups were then exchanged with BBr3, and then modified with nucleophiles. Ditelechelic α,ω-borane-functionalized polymers were obtained through atom transfer radical coupling (ATRC) of the silane-end-functionalized polymers followed by exchange with BBr3 and subsequent reaction with nucleophiles. Self-assembly of the borane-functionalized mono- and ditelechelic polymers into supramol. structures by reversible noncovalent and covalent interactions including Lewis acid-base complexation and boroxine formation was explored.
    45. 45
      Kim, C.; Ejima, H.; Yoshie, N. Polymers with autonomous self-healing ability and remarkable reprocessability under ambient humidity conditions. J. Mater. Chem. A 2018, 6 (40), 19643– 19652,  DOI: 10.1039/C8TA04769C
      45
      Polymers with autonomous self-healing ability and remarkable reprocessability under ambient humidity conditions
      Kim, Chaehoon; Ejima, Hirotaka; Yoshie, Naoko
      Journal of Materials Chemistry A: Materials for Energy and Sustainability (2018), 6 (40), 19643-19652CODEN: JMCAET; ISSN:2050-7496. (Royal Society of Chemistry)
      The use of moisture in self-healing polymeric materials is a very attractive option given the practical environments in which the materials are used. Herein, we incorporated tetrahedral boronate-esters bearing B-N dative bonds as dynamic crosslinks into polymers, which led to moisture-induced self-healing abilities in their bulk states. Owing to the higher rate of ester formation over tetrahedral boronate-ester hydrolysis under wet conditions, these polymers invariably maintain a sufficient no. of dynamic crosslinks to facilitate a combination of autonomous healing behavior and mech. strength, which makes them unique compared to other previously developed water-triggered self-healing polymers. The self-healed materials maintain good mech. properties, with fracture stresses of ∼2 MPa, and aging of the cut surfaces does not affect their healing efficiency. Furthermore, the tetrahedral boronate-ester bonds exhibit dual stimuli-responsive dynamic behavior triggered by either moisture or heat, resulting in network polymers with remarkable reprocessabilities.
    46. 46
      Silverstein, R. M.; Webster, F. X.; Kiemle, D. J.; Bryce, D. L. Spectrometric Identification of Organic Compounds; John Wiley & Sons: 2015.
      There is no corresponding record for this reference.
    47. 47
      Foran, G. Y.; Harris, K. J.; Brook, M. A.; Macphail, B.; Goward, G. R. Solid State NMR Study of Boron Coordination Environments in Silicone Boronate (SiBA) Polymers. Macromolecules 2019, 52 (3), 1055– 1064,  DOI: 10.1021/acs.macromol.8b02442
      47
      Solid State NMR Study of Boron Coordination Environments in Silicone Boronate (SiBA) Polymers
      Foran, Gabrielle Y.; Harris, Kristopher J.; Brook, Michael A.; MacPhail, Benjamin; Goward, Gillian R.
      Macromolecules (Washington, DC, United States) (2019), 52 (3), 1055-1064CODEN: MAMOBX; ISSN:0024-9297. (American Chemical Society)
      Silicone polymers possess very unusual properties when compared to org. polymers. The addn. of grafted boronic acid groups allows for elastomeric film formation through self-assocn. and enhances compatibility with biol. systems by increasing elastomer miscibility with aq. systems, pH tunability, and the ability to bind to saccharides. Boronic acid dimerization was reported to be the origin of crosslinking in silicone boronic acids, but the boron environments involved in this process remain poorly understood. Solid state 11B NMR was used to investigate the boron coordination environments in these materials. 11B quadrupolar line shape fitting, a method previously used to characterize minerals and amorphous glasses, revealed structural information, including coordination no. and coordination sphere symmetry. Chain extension in these materials was attributed to hydrogen bonding between boronic acids and could be identified by the presence of three-coordinate boron sites. Crosslinking between boronic acid sites through four-coordinate, dative bonded boron centers was found to be the origin of elastomer formation; the oxygen Lewis bases on the silicone backbone do not appear to play a role. The proportion of boronic acid in the material and location of the boronic acid sites-telechelic vs. pendant-both impacted crosslinking in these materials.
    48. 48
      Parks, D. J.; Piers, W. E.; Parvez, M.; Atencio, R.; Zaworotko, M. J. Synthesis and Solution and Solid-State Structures of Tris(pentafluorophenyl)borane Adducts of PhC(O)X (X = H, Me, OEt, NPri2). Organometallics 1998, 17 (7), 1369– 1377,  DOI: 10.1021/om9710327
      48
      Synthesis and Solution and Solid-State Structures of Tris(pentafluorophenyl)borane Adducts of PhC(O)X (X = H, Me, OEt, NPri2)
      Parks, Daniel J.; Piers, Warren E.; Parvez, Masood; Atencio, Reinaldo; Zaworotko, Michael J.
      Organometallics (1998), 17 (7), 1369-1377CODEN: ORGND7; ISSN:0276-7333. (American Chemical Society)
      Reaction of the highly electrophilic borane B(C6F5)3 with the carbonyl Lewis bases benzaldehyde, acetophenone, Et benzoate, and N,N-diisopropylbenzamide led to isolation of the cryst. adducts 1-H, 1-Me, 1-OEt, and 1-NPr, resp., in good to excellent yields (63-89%). Equil. measurements and exchange expts. indicated that the order of basicity (from highest to lowest) of these bases toward B(C6F5)3 follows the order N,N-diisopropylbenzamide > benzaldehyde > acetophenone > Et benzoate. The soln. and solid-state structures were probed to rationalize these observations. In soln., the borane coordinates to the carbonyl lone pair syn to H and Me in the aldehyde and ketone adducts, as indicated by 1H/19F NOE difference expts. The same coordination geometry was obsd. in the solid state upon x-ray diffraction anal. of the two adducts. The added front strain assocd. with the ketone adduct (C-O-B =133.6(3)° vs 126.7(5)° for the benzaldehyde complex) accounts for the obsd. order of basicity with these two bases. For Et benzoate and N,N-diisopropylbenzamide, the borane coordinates syn to the Ph group in both soln. and the solid state. In addn. to the carbonyl oxygen-boron interaction, the two complexes engage in a π-stacking interaction between one of the borane C6F5 rings and the syn Ph group. In addn. to the structural proof of this interaction in the solid state, variable-temp. 19F NMR expts. suggest it is important in the soln. structures of these adducts as well.
    49. 49
      Komon, Z. J. A.; Bu, X.; Bazan, G. C. Synthesis of Butene-Ethylene and Hexene-Butene-Ethylene Copolymers from Ethylene via Tandem Action of Well-Defined Homogeneous Catalysts. J. Am. Chem. Soc. 2000, 122 (8), 1830– 1831,  DOI: 10.1021/ja994222c
      49
      Synthesis of butene-ethylene and hexene-butene-ethylene copolymers from ethylene via tandem action of well-defined homogeneous catalysts
      Komon, Zachary J. A.; Bu, Xianhui; Bazan, Guillermo C.
      Journal of the American Chemical Society (2000), 122 (8), 1830-1831CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)
      A tandem catalysis system for the synthesis of polyethylene with Et or with Et and Bu branches was developed based on the well-defined homogeneous catalysts [(C6H5)2PC6H4C(OB(C6F5)3)O-κ2P,O]Ni(η3-CH2CMeCH2) and {[(η5-C5Me4)SiMe2(η1-NCMe3)]TiMe}{MeB(C6F5)3}. Their activity to produce butene-ethylene copolymers from ethylene was studied with respect to branching percentage. Me aluminoxane was no longer required and the branching in the polymer structure depended linearly from the ratio of the 2 precatalysts. Extensive supporting material (exptl. procedures, 13C NMR data of polymers, x-ray data for Ni catalyst) is available via the Internet.
    50. 50
      Pringsheim, E.; Terpetschnig, E.; Piletsky, S. A.; Wolfbeis, O. S. A Polyaniline with Near-Infrared Optical Response to Saccharides. Adv. Mater. 1999, 11 (10), 865– 868,  DOI: 10.1002/(SICI)1521-4095(199907)11:10<865::AID-ADMA865>3.0.CO;2-B
      50
      A polyaniline with near-infrared optical response to saccharides
      Pringsheim, Erika; Terpetschnig, Ewald; Piletsky, Sergey A.; Wolfbeis, Otto S.
      Advanced Materials (Weinheim, Germany) (1999), 11 (10), 865-868CODEN: ADVMEW; ISSN:0935-9648. (Wiley-VCH Verlag GmbH)
      A sugar-binding polymer film capable of continuous sensing was prepd. by copolymn. of aniline and 3-aminophenylboronic acid and ammonium peroxodisulfate oxidn. Its absorption spectrum between 500-800 nm undergoes large changes on addn. of various saccharides (glucose, fructose, sorbitol, mannitol, saccharose, and glycerol) at neutral pH, changes which are dependent on the saccharide conc. and are fully reversible. These films represent an interesting alternative to enzyme-based glucose sensors because of their ease of prepn., compatibility with light emitting devices and diode laser light sources, and their thermal and temporal stability.
    51. 51
      Liu, H.; Li, Y.; Sun, K.; Fan, J.; Zhang, P.; Meng, J.; Wang, S.; Jiang, L. Dual-Responsive Surfaces Modified with Phenylboronic Acid-Containing Polymer Brush To Reversibly Capture and Release Cancer Cells. J. Am. Chem. Soc. 2013, 135 (20), 7603– 7609,  DOI: 10.1021/ja401000m
      51
      Dual-Responsive Surfaces Modified with Phenylboronic Acid-Containing Polymer Brush To Reversibly Capture and Release Cancer Cells
      Liu, Hongliang; Li, Yingying; Sun, Kang; Fan, Junbing; Zhang, Pengchao; Meng, Jingxin; Wang, Shutao; Jiang, Lei
      Journal of the American Chemical Society (2013), 135 (20), 7603-7609CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)
      Artificial stimuli-responsive surfaces that can mimic the dynamic function of living systems have attracted much attention. However, there exist few artificial systems capable of responding to dual- or multistimulation as the natural system does. Herein, we synthesize a pH and glucose dual-responsive surface by grafting poly(acrylamidophenylboronic acid) (polyAAPBA) brush from aligned silicon nanowire (SiNW) array. The as-prepd. surface can reversibly capture and release targeted cancer cells by precisely controlling pH and glucose concn., exhibiting dual-responsive AND logic. In the presence of 70 mM glucose, the surface is pH responsive, which can vary from a cell-adhesive state to a cell-repulsive state by changing the pH from 6.8 to 7.8. While keeping the pH at 7.8, the surface becomes glucose responsive-capturing cells in the absence of glucose and releasing cells by adding 70 mM glucose. Through simultaneously changing the pH and glucose concn. from pH 6.8/0 mM glucose to pH 7.8/70 mM glucose, the surface is dual responsive with the capability to switch between cell capture and release for at least 5 cycles. The cell capture and release process on this dual-responsive surface is noninvasive with cell viability higher than 95%. Moreover, topog. interaction between the aligned SiNW array and cell protrusions greatly amplifies the responsiveness and accelerates the response rate of the dual-responsive surface between cell capture and release. The responsive mechanism of the dual-responsive surface is systematically studied using a quartz crystal microbalance, which shows that the competitive binding between polyAAPBA/sialic acid and polyAAPBA/glucose contributes to the dual response. Such dual-responsive surface can significantly impact biomedical and biol. applications including cell-based diagnostics, in vivo drug delivery, etc.
    52. 52
      Barriet, D.; Yam, C. M.; Shmakova, O. E.; Jamison, A. C.; Lee, T. R. 4-Mercaptophenylboronic Acid SAMs on Gold: Comparison with SAMs Derived from Thiophenol, 4-Mercaptophenol, and 4-Mercaptobenzoic Acid. Langmuir 2007, 23 (17), 8866– 8875,  DOI: 10.1021/la7007733
      52
      4-Mercaptophenylboronic Acid SAMs on Gold: Comparison with SAMs Derived from Thiophenol, 4-Mercaptophenol, and 4-Mercaptobenzoic Acid
      Barriet, David; Yam, Chi Ming; Shmakova, Olga E.; Jamison, Andrew C.; Lee, T. Randall
      Langmuir (2007), 23 (17), 8866-8875CODEN: LANGD5; ISSN:0743-7463. (American Chemical Society)
      We report the formation and characterization of self-assembled monolayers (SAMs) derived from the adsorption of 4-mercaptophenylboronic acid (MPBA) on gold. For comparison, SAMs derived from the adsorption of thiophenol (TP), 4-mercaptophenol (MP), and 4-mercaptobenzoic acid (MBA) were also examd. The structure and properties of the SAMs were evaluated by ellipsometry, contact-angle goniometry, polarization-modulation IR reflection-absorption spectroscopy (PM-IRRAS), and XPS. Specifically, ellipsometry was used to assess the formation of monolayer films, and contact angle measurements were used to det. the surface hydrophilicity and homogeneity. Sep., PM-IRRAS was used to evaluate the mol. compn. and orientation as well as the intermol. hydrogen bonding within the SAMs. Finally, XPS was used to evaluate the film compn. and surface coverage (i.e., packing d.), which was obsd. to increase in the following order: TP < MP < MPBA < MBA. A rationalization for the obsd. packing differences is presented. The XPS data indicate further that ultrahigh vacuum conditions induce the partial dehydration of MPBA SAMs with the concomitant formation of surface boronic anhydride species. Overall, the anal. data collectively show that the MPBA moieties in the SAMs exist in the acid form rather than the anhydride form under ambient lab. conditions. Furthermore, stability studies find that MPBA SAMs are surprisingly labile in basic soln., where the terminal B-C bonds are cleaved by the attack of hydroxide ion and strongly basic amine nucleophiles. The unanticipated lability obsd. here should be considered by those wishing to use MPBA moieties in carbohydrate-sensing applications.
    53. 53
      Sana, M.; Leroy, G.; Wilante, C. Enthalpies of formation and bond energies in lithium, beryllium, and boron derivatives. 2. Dative, single, and triple bonds. Organometallics 1992, 11 (2), 781– 787,  DOI: 10.1021/om00038a042
      53
      Enthalpies of formation and bond energies in lithium, beryllium, and boron derivatives. 2. Dative, single, and triple bonds
      Sana, Michel; Leroy, Georges; Wilante, Claude
      Organometallics (1992), 11 (2), 781-7CODEN: ORGND7; ISSN:0276-7333.
      For a set of small XYHn singlet-state mols. (where X stands for Li, Be, or B and Y is one of the second-row atoms), the enthalpies of formation at the MP4(sdtq)/6-311++G(3df,2p) level by using MP2(full)/6-31G(d,p) fully optimized structures were calcd. At this level of theory, the heats of formation are expected to be in the range of the so-called chem. accuracy (±1 kcal/mol). Some alkyl derivs. of the previous XYHn compds. were studied at the RHF/6-31G(d) level (with fully optimized geometries). The theor. enthalpies of formation reproduce the available exptl. results quite satisfactorily. In addn. to compds. with usual dative single bonds, the mols. with covalent (nondative) single B-N and B-O bonds were also described. The available (exptl. and theor.) data to calc. new bond energies for lithium, beryllium, and boron derivs. were used.
    54. 54
      Chen, H.; Yao, X.; Ma, X.; Tian, H. Amorphous, Efficient, Room-Temperature Phosphorescent Metal-Free Polymers and Their Applications as Encryption Ink. Adv. Opt. Mater. 2016, 4 (9), 1397– 1401,  DOI: 10.1002/adom.201600427
      54
      Amorphous, Efficient, Room-Temperature Phosphorescent Metal-Free Polymers and Their Applications as Encryption Ink
      Chen, Hui; Yao, Xuyang; Ma, Xiang; Tian, He
      Advanced Optical Materials (2016), 4 (9), 1397-1401CODEN: AOMDAX; ISSN:2195-1071. (Wiley-VCH Verlag GmbH & Co. KGaA)
      In this paper phosphorescent metal-free polymers were synthesized by radical binary copolymn., by employing acrylamide and room-temp. phosphorescence (RTP) phosphors contg. a 2-bromo-5-hydroxybenzaldehyde deriv., a α-bromonaphthalene deriv., and a 4-bromo-1,8-naphthalic anhydride deriv., resp. Their applications as encryption ink are demonstrated as well. The hydrogen bonding between polymeric chains greatly enhances the RTP intensity. The crosslinking degree of the network formed by N,N-di-Me acrylamide was very poor, which resulted in the decrease of luminescent decay lifetimes at 580 nm. The hydrogen bonding between polymeric chains greatly enhances the RTP intensity. Hydrogen-bond crosslinking between the polymeric chains not only immobilized the RTP phosphors, but also endowed the materials with reversibly controllable characteristics due to the nature of noncovalent interactions. As a result, the materials exhibit water-responsive properties.
    55. 55
      Yin, X.; Stöver, H. D. H. Hydrogel Microspheres by Thermally Induced Coacervation of Poly(N, N-dimethylacrylamide-co-glycidyl methacrylate) Aqueous Solutions. Macromolecules 2003, 36 (26), 9817– 9822,  DOI: 10.1021/ma034809i
      55
      Hydrogel Microspheres by Thermally Induced Coacervation of Poly(N,N-dimethylacrylamide-co-glycidyl methacrylate) Aqueous Solutions
      Yin, Xiangchun; Stoever, Harald D. H.
      Macromolecules (2003), 36 (26), 9817-9822CODEN: MAMOBX; ISSN:0024-9297. (American Chemical Society)
      Aq. solns. of poly(N,N-dimethylacrylamide-co-glycidyl methacrylate) (DMA-GMA) are shown to undergo liq.-liq. phase sepn. upon heating. The phase transition temps. as measured by the cloud point method decreased with increasing levels of the hydrophobic GMA comonomer. The initially formed coacervate microdroplets could be cross-linked by addn. of polyamines. The morphol. of the resulting hydrogel microspheres depends on both coacervation conditions and crosslinking conditions. Specifically, colloidally stable microspheres were formed at temps. slightly above the phase transition temps., while agglomeration took place at higher temps. Low mol. wt. polyamines are effective internal cross-linkers for the coacervate droplets, while higher mol. wt. polyamines resulted in agglomeration. Addn. of sodium dodecyl sulfate increased the phase transition temps. of polymer solns. dramatically, while addn. of poly(vinylpyrrolidone) (PVP) did not affect the phase sepn. temps. and could be used as a steric stabilizer.
    56. 56
      Gan, N.; Shi, H.; An, Z.; Huang, W. Recent Advances in Polymer-Based Metal-Free Room-Temperature Phosphorescent Materials. Adv. Funct. Mater. 2018, 28 (51), 1802657,  DOI: 10.1002/adfm.201802657
      There is no corresponding record for this reference.
    57. 57
      Carey, R. I.; Folkers, J. P.; Whitesides, G. M. Self-Assembled Monolayers Containing. omega.-Mercaptoalkyl boronic Acids Adsorbed onto Gold Form a Highly Cross-Linked, Thermally Stable Borate Glass Surface. Langmuir 1994, 10 (7), 2228– 2234,  DOI: 10.1021/la00019a033
      57
      Self-Assembled Monolayers Containing ω-Mercaptoalkyl boronic Acids Adsorbed onto Gold Form a Highly Cross-Linked, Thermally Stable Borate Glass Surface
      Carey, Robert I.; Folkers, John P.; Whitesides, George M.
      Langmuir (1994), 10 (7), 2228-34CODEN: LANGD5; ISSN:0743-7463.
      This paper describes the prepn. and properties of self-assembled monolayers (SAMs) obtained by the adsorption of 11-mercaptoundecanyl-1-boronic acid, HS(CH2)11B(OH)2 onto the surface of gold substrates. In soln. in dry hydrocarbon solvents, 11-mercaptoundecanyl-1-boronic acid reversibly forms a tri-ω-mercaptoalkylboroxine that adsorbs onto gold and forms a hydrophobic boroxine bilayer: this bilayer is marginally stable in air; it can be completely hydrolyzed to a monolayer in aq. ethanol, yielding a hydrophilic, 17-Å-thick SAM that presents boronic acid groups at its surface. Under water-satd. cyclooctane, SAMs exposing the boronic acid groups do not titrate appreciably over a pH range of 0 to 11-i.e., the contact angle is independent of the pH of the contacting aq. soln. At pH 13-14, there is a sharp increase in the hydrophilicity of the SAM, indicating an onset of ionization of the boronic acid groups. In dry hydrocarbon solvents or under vacuum, the boronic acid tail groups dehydrate rapidly and reversibly and form a cross-linked borate glass at the surface. At 147° in hexadecane, SAMs having this cross-linked borate glass as a surface are at least 5 times more stable to thermal desorption than SAMs of the structurally analogous 11-hydroxyundecane-1-thiol. The boronic acid/anhydride groups of SAMs of 1 can be derivatized with solns. of certain cis-diols (esp. pinanediol), catechols, and alkyltrichlorosilanes to yield hydrophobic structures consisting of an inner monomer derived from 1 and an outer partial monolayer of the boronate ester or the alkylsiloxane.
    58. 58
      Ma, X.; Xu, C.; Wang, J.; Tian, H. Amorphous Pure Organic Polymers for Heavy-Atom-Free Efficient Room-Temperature Phosphorescence Emission. Angew. Chem., Int. Ed. 2018, 57 (34), 10854– 10858,  DOI: 10.1002/anie.201803947
      58
      Amorphous Pure Organic Polymers for Heavy-Atom-Free Efficient Room-Temperature Phosphorescence Emission
      Ma, Xiang; Xu, Chao; Wang, Jie; Tian, He
      Angewandte Chemie, International Edition (2018), 57 (34), 10854-10858CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)
      Pure org., heavy-atom-free room-temp. phosphorescence (RTP) materials have attracted much attention and have potential applications in photoelec. and biochem. material fields owing to their rich excited state properties. They offer long luminescent lifetime, diversified design, and facile prepn. However, recent achievements of efficient phosphorescence under ambient conditions mainly focus on ordered crystal lattices or embedding into rigid matrixes, which require strict growth conditions and have poor reproducibility. Herein, we developed a concise approach to give RTP with a decent quantum yield and ultralong phosphorescence lifetime in the amorphous state by radical binary copolymn. of acrylamide and different phosphors with oxygen-contg. functional groups. The crosslinked hydrogen-bonding networks between the polymeric chains immobilize phosphors to suppress non-radiative transitions and provide a microenvironment to shield quenchers.
    59. 59
      Zhang, X.; Xie, T.; Cui, M.; Yang, L.; Sun, X.; Jiang, J.; Zhang, G. General Design Strategy for Aromatic Ketone-Based Single-Component Dual-Emissive Materials. ACS Appl. Mater. Interfaces 2014, 6 (4), 2279– 2284,  DOI: 10.1021/am405209w
      59
      General Design Strategy for Aromatic Ketone-Based Single-Component Dual-Emissive Materials
      Zhang, Xuepeng; Xie, Tongqing; Cui, Minxin; Yang, Li; Sun, Xingxing; Jiang, Jun; Zhang, Guoqing
      ACS Applied Materials & Interfaces (2014), 6 (4), 2279-2284CODEN: AAMICK; ISSN:1944-8244. (American Chemical Society)
      Materials with both fluorescence and room-temp. phosphorescence (RTP) can be useful in the field of optoelectronics. Here the authors present a general strategy, taking advantage of carbonyl compds., which have been known to possess efficient intersystem crossing with high triplet state yield, as well as a strongly fluorescent intramol. charge-transfer (ICT) state, to produce materials with both fluorescence and RTP at the same time, or dual-emission. In the presented model systems, in order to generate a suitable ICT state, Lewis acid binding to arom. ketone derivs. has been proved to be a viable method. The authors have selected AlCl3, BCl3, BF3, and GdCl3 as binding Lewis acids, in that they exhibit sufficiently strong binding affinity toward the arom. ketone derivs. to afford stable complexes and yet do not possess low-lying electronic transitions vs the ligands. The authors have successfully obsd. dual-emission from these designed complexes in polymers, which act to suppress competitive thermal decay at room temp. One of the complexes is particularly interesting as it is dual-emissive in the cryst. state. Single-crystal XRD reveals that the mol. forms multiple hydrogen bonds with its neighbors in crystals, which may significantly enhance the rigidity of the environment.
    60. 60
      Liu, Y.; Zhao, J.; Iagatti, A.; Bussotti, L.; Foggi, P.; Castellucci, E.; Di Donato, M.; Han, K.-L. A Revisit to the Orthogonal Bodipy Dimers: Experimental Evidence for the Symmetry Breaking Charge Transfer-Induced Intersystem Crossing. J. Phys. Chem. C 2018, 122 (5), 2502– 2511,  DOI: 10.1021/acs.jpcc.7b10213
      60
      A Revisit to the Orthogonal Bodipy Dimers: Experimental Evidence for the Symmetry Breaking Charge Transfer-Induced Intersystem Crossing
      Liu, Ya; Zhao, Jianzhang; Iagatti, Alessandro; Bussotti, Laura; Foggi, Paolo; Castellucci, Elena; Di Donato, Mariangela; Han, Ke-Li
      Journal of Physical Chemistry C (2018), 122 (5), 2502-2511CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)
      A series of Bodipy dimers with orthogonal conformation were prepd. The photophys. properties were studied with steady-state and time-resolved transient spectroscopies. We found the triplet-state quantum yield is highly dependent on the solvent polarity in the orthogonally linked sym. Bodipy dimers, and the intersystem crossing (ISC) is efficient in solvents with moderate polarity. The photoinduced symmetry-breaking charge transfer (SBCT) in polar solvents was confirmed by femtosecond transient absorption spectroscopy, with the charge sepn. (CS) kinetics on the order of a few picoseconds and the charge recombination (CR) process occurring on the nanosecond time scale(coating process) in dichloromethane. These observations are supported by the calcn. of the charge sepd. state (CSS) energy levels, which are high in nonpolar solvents, and lower in polar solvents, thus the CR-induced ISC has the largest driven force in solvents with moderate polarity. These results clarify the mechanism of SOCT-ISC in the orthogonally sym. Bodipy dimers. The acquired information, relating mol. structure and ISC property, will be useful for devising new strategies to induce ISC in heavy atom-free org. chromophores.
    61. 61
      Iwata, S.; Tanaka, J.; Nagakura, S. Phosphorescence of the Charge-Transfer Triplet States of Some Molecular Complexes. J. Chem. Phys. 1967, 47 (7), 2203– 2209,  DOI: 10.1063/1.1703292
      61
      Phosphorescence of the charge-transfer triplet states of some molecular complexes
      Iwata, Suehiro; Tanaka, Jiro; Nagakura, Saburo
      Journal of Chemical Physics (1967), 47 (7), 2203-9CODEN: JCPSA6; ISSN:0021-9606.
      The phosphorescence spectra of some charge-transfer complexes were studied in glassy soln. at 77°K. Long-lived emission spectra which were different from the phosphorescence spectra of the constituent mols. were observed for the 1,2,4,5-tetracyanobenzene complexes with mesitylene, durene, and hexamethylbenzene. The max. of the long-lived emission spectra were found to shift to lower frequencies as the ionization potential of the donor was decreased; e.g., max. appear at 19.8, 19.5, and 18.3 (×103 cm.-1) in the complexes with mesitylene, durene, and hexamethylbenzene, resp. This shift is parallel to that observed for charge-transfer fluorescence spectra which exhibit a mirror-image relation with the corresponding absorption spectra. Similar long-lived emission spectra were also observed for complexes contg. pyromellitic dianhydride, tetrachlorophthalic anhydride, and phthalic anhydride as electron acceptors. A combination of theory and expt. indicates that the long-lived emission is attributable to a transition from a triplet state of charge-transfer character. This is the 1st observation of a "charge-transfer triplet state." The lifetime of the phosphorescence due to the charge-transfer triplet state was measured. The observed lifetime decreases with increasing donor ability for a series of complexes with a fixed electron acceptor. The mechanism of singlet-triplet mixing in the charge-transfer complexes is discussed.
    62. 62
      Snyder, R.; Testa, A. C. Reversible phosphorescence quenching of some aromatic ketones. J. Phys. Chem. 1979, 83 (23), 3041– 3044,  DOI: 10.1021/j100486a022
      62
      Reversible phosphorescence quenching of some aromatic ketones
      Snyder, R.; Testa, A. C.
      Journal of Physical Chemistry (1979), 83 (23), 3041-4CODEN: JPCHAX; ISSN:0022-3654.
      An investigation of the phosphorescence behavior of Ph2CO, anthrone and fluorenone (I) and their 1:1 EDA (electron donor-acceptor) complexes with BCl3 reveals that (a) complexation generates a new charge-transfer phosphorescence appearing at 505 nm in the 1st 2 mols., and (b) complexation can readily be reversed to regenerate the phosphorescence spectrum of the free ketone, the electron donor in these studies. With I the lack of phosphorescence from the complex may be due to the charge-transfer state lying above the lowest nonphosphorescing 3π,π state of I. Formation consts. and phosphorescence quantum yields for the EDA complexes of Ph2CO and anthrone were detd.
    63. 63
      Mo, Y.; Song, L.; Wu, W.; Zhang, Q. Charge Transfer in the Electron Donor-Acceptor Complex BH3NH3. J. Am. Chem. Soc. 2004, 126 (12), 3974– 3982,  DOI: 10.1021/ja039778l
      63
      Charge Transfer in the Electron Donor-Acceptor Complex BH3NH3
      Mo, Yirong; Song, Lingchun; Wu, Wei; Zhang, Qianer
      Journal of the American Chemical Society (2004), 126 (12), 3974-3982CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)
      As a simple yet strongly binding electron donor-acceptor (EDA) complex, BH3NH3 serves as a good example to study the electron pair donor-acceptor complexes. We employed both the ab initio valence bond (VB) and block-localized wave function (BLW) methods to explore the electron transfer from NH3 to BH3. Conventionally, EDA complexes have been described by two diabatic states: one neutral state and one ionic charge-transferred state. Ab initio VB SCF (VBSCF) computations generate the energy profiles of the two diabatic states together with the adiabatic (ground) state. Our calcns. evidently demonstrated that the electron transfer between NH3 and BH3 falls in the abnormal regime where the reorganization energy is less than the exoergicity of the reaction. The nature of the NH3-BH3 interaction is probed by an energy decompn. scheme based on the BLW method. We found that the variation of the charge-transfer energy with the donor-acceptor distance is insensitive to the computation levels and basis sets, but the estn. of the amt. of electron transferred heavily depends on the population anal. procedures. The recent resurgence of interest in the nature of the rotation barrier in ethane prompted us to analyze the conformational change of BH3NH3, which is an isoelectronic system with ethane. We found that the preference of the staggered structure over the eclipsed structure of BH3NH3 is dominated by the Pauli exchange repulsion.
    64. 64
      Yoshino, J.; Kano, N.; Kawashima, T. Fluorescent azobenzenes and aromatic aldimines featuring an N-B interaction. Dalton Trans. 2013, 42 (45), 15826– 15834,  DOI: 10.1039/c3dt51689j
      64
      Fluorescent azobenzenes and aromatic aldimines featuring an N-B interaction
      Yoshino, Junro; Kano, Naokazu; Kawashima, Takayuki
      Dalton Transactions (2013), 42 (45), 15826-15834CODEN: DTARAF; ISSN:1477-9226. (Royal Society of Chemistry)
      A review. Azobenzenes are constituents of the commonly and widely used azo dyes. Many dyes, except for the azo dyes, have been utilized for fluorescent materials. However, there are only a few fluorescent azobenzene derivs. and their fluorescence efficiencies are quite low. The current perspective provides an account of the fluorescent azobenzenes and arom. aldimines featuring an N-B interaction. Incorporation of the intramol. N-B interaction by using the bis(pentafluorophenyl)boryl group makes the azobenzenes and arom. aldimines fluorescent with a range of colors. Some of them fluoresce with extraordinarily high fluorescence quantum yields. Their synthesis, structures, fluorescence properties, and applications are discussed.
    65. 65
      Yoshino, J.; Kano, N.; Kawashima, T. Synthesis of the most intensely fluorescent azobenzene by utilizing the B-N interaction. Chem. Commun. 2007, (6), 559– 561,  DOI: 10.1039/B615966D
      65
      Synthesis of the most intensely fluorescent azobenzene by utilizing the B-N interaction
      Yoshino, Junro; Kano, Naokazu; Kawashima, Takayuki
      Chemical Communications (Cambridge, United Kingdom) (2007), (6), 559-561CODEN: CHCOFS; ISSN:1359-7345. (Royal Society of Chemistry)
      Chelate 2-boryl-substituted azobenzenes exhibit intense fluorescence at 500-520 nm with quantum yields of 0.23-0.76, being excited at 380-440 nm. Lithiation/borylation of 2-iodo-4'-R-azobenzenes (1, 4; R = H, OMe) affords diaryl(4-R-phenylazo-κN2-phenyl-κC)boranes (3a, 3c, aryl = C6F5, R = H, OMe; 3b, aryl = 4-FC6H4, R = H). A boron-substituted azobenzene 3c, (E)-[2-(4-methoxyphenylazo)phenyl]bis(pentafluorophenyl)borane, presented the most intense fluorescence among the azobenzene derivs.
    66. 66
      Paddon-Row, M. N.; Anderson, C. D.; Houk, K. N. Computational Evaluation of Enantioselective Diels-Alder Reactions Mediated by Corey’s Cationic Oxazaborolidine Catalysts. J. Org. Chem. 2009, 74 (2), 861– 868,  DOI: 10.1021/jo802323p
      66
      Computational Evaluation of Enantioselective Diels-Alder Reactions Mediated by Corey's Cationic Oxazaborolidine Catalysts
      Paddon-Row, Michael N.; Anderson, Christopher D.; Houk, K. N.
      Journal of Organic Chemistry (2009), 74 (2), 861-868CODEN: JOCEAH; ISSN:0022-3263. (American Chemical Society)
      The cationic oxazaborolidine-catalyzed Diels-Alder reactions of butadiene and five dienophiles were studied using d. functional theory (B3LYP/6-31G(d)). In each case, the computational results successfully reproduce the exptl. obsd. sense of stereoinduction and enantiomeric ratio. The computed structures of the lowest energy Lewis acid-carbonyl complexes and Lewis acid-transition state complexes are closely related to the models for stereoselection proposed by Corey and co-workers.
    67. 67
      Zhao, C.; Jin, Y.; Wang, J.; Cao, X.; Ma, X.; Tian, H. Heavy-atom-free amorphous materials with facile preparation and efficient room-temperature phosphorescence emission. Chem. Commun. 2019, 55 (37), 5355– 5358,  DOI: 10.1039/C9CC01594A
      67
      Heavy-atom-free amorphous materials with facile preparation and efficient room-temperature phosphorescence emission
      Zhao, Changxing; Jin, Yanhuan; Wang, Jie; Cao, Xiaoming; Ma, Xiang; Tian, He
      Chemical Communications (Cambridge, United Kingdom) (2019), 55 (37), 5355-5358CODEN: CHCOFS; ISSN:1359-7345. (Royal Society of Chemistry)
      Amorphous pure org. room-temp. phosphorescent small mols. without heavy atoms, based on the intermol. hydrogen bonding network for the immobilization of luminophores, were designed and facilely prepd. via modification of heavy-atom-free luminophores onto β-cyclodextrin.
    68. 68
      Yang, X.; Guo, H.; Xu, X.; Sun, Y.; Zhou, G.; Ma, W.; Wu, Z. Enhancing Molecular Aggregations by Intermolecular Hydrogen Bonds to Develop Phosphorescent Emitters for High-Performance Near-Infrared OLEDs. Adv. Sci. 2019, 6 (7), 1801930,  DOI: 10.1002/advs.201801930
      68
      Enhancing Molecular Aggregations by Intermolecular Hydrogen Bonds to Develop Phosphorescent Emitters for High-Performance Near-Infrared OLEDs
      Yang Xiaolong; Guo Haoran; Xu Xianbin; Sun Yuanhui; Zhou Guijiang; Ma Wei; Wu Zhaoxin
      Advanced science (Weinheim, Baden-Wurttemberg, Germany) (2019), 6 (7), 1801930 ISSN:2198-3844.
      Phosphorescent near-infrared (NIR) organic light-emitting devices (OLEDs) have drawn increasing attention for their promising applications in the fields such as photodynamic therapy and night-vision readable displays. Here, three simple phosphorescent Pt(II) complexes are synthesized, and their intermolecular interactions are investigated in crystals and neat films by X-ray single crystal diffraction and grazing-incidence wide-angle X-ray scattering, respectively. The photophysical properties, molecular aggregation (including Pt-Pt interaction), molecular packing orientation, and electron transport ability are all influenced by the strong intermolecular hydrogen bonds. Consequently, the nondoped OLEDs based on tBu-Pt and F-Pt show electroluminescent emissions in NIR region with the highest external quantum efficiencies of 13.9% and 16.7%, respectively.
    69. 69
      Chen, J.; Yu, T.; Ubba, E.; Xie, Z.; Yang, Z.; Zhang, Y.; Liu, S.; Xu, J.; Aldred, M. P.; Chi, Z. Achieving Dual-Emissive and Time-Dependent Evolutive Organic Afterglow by Bridging Molecules with Weak Intermolecular Hydrogen Bonding. Adv. Opt. Mater. 2019, 7 (7), 1801593,  DOI: 10.1002/adom.201801593
      There is no corresponding record for this reference.

  • Supporting Information

    Supporting Information

    The Supporting Information is available free of charge at https://pubs.acs.org/doi/10.1021/acsapm.9b01027.

    • Experimental details and additional discussion of BAA, BAD, and BAS, 1H NMR, solid-state 1H NMR, solid-state 11B NMR, FTIR, XPS, XRD, UV–vis, and photophysical properties (PDF)

    • Movie S1: RTP performance of BAAs (MP4)

    • Movie S2: RTP-based anticounterfeiting application of BAAs (MP4)


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