UV–Vis Absorption Spectroscopy of Polonium(IV) Chloride Complexes: An Electronic Structure Theory Study
- Ange StoïanovAnge StoïanovSUBATECH, UMR CNRS 6457, IN2P3/IMT Atlantique/Université de Nantes, 4 rue Alfred Kastler, BP 20722, 44307 Nantes Cedex 3, FranceMore by Ange Stoïanov
- ,
- Julie ChampionJulie ChampionSUBATECH, UMR CNRS 6457, IN2P3/IMT Atlantique/Université de Nantes, 4 rue Alfred Kastler, BP 20722, 44307 Nantes Cedex 3, FranceMore by Julie Champion
- , and
- Rémi Maurice*Rémi Maurice*E-mail: [email protected]SUBATECH, UMR CNRS 6457, IN2P3/IMT Atlantique/Université de Nantes, 4 rue Alfred Kastler, BP 20722, 44307 Nantes Cedex 3, FranceMore by Rémi Maurice
Abstract
More than a hundred years after its discovery, the chemistry of the polonium radioelement is still largely unknown. However, it is quite clear that the properties of this heavy element (Z = 84) may be affected by relativistic effects, in particular scalar relativistic effects and the so-called spin–orbit coupling (SOC). In this Article, we revisit the interpretation of UV–vis absorption spectra of polonium(IV) complexes in HCl medium, reported decades ago. From the data, two complexes were hypothesized, complex I with a maximum of absorption at 344 nm (at low HCl concentration) and complex II with a maximum at 418 nm (the only visible peak for HCl concentrations above 0.5 M). By monitoring the absorbance at 344 and 418 nm as a function of both the HCl concentration and the pH, complex I was formulated as [Po(OH)Clx]3–x while complex II was formulated as [PoCl2+x]2–x. In this work, we study the ground-state geometries of the [Po(OH)Clx]3–x and [PoCl2+x]2–x complexes for x = 4–2, i.e. for the most probable complexes, with density functional theory (DFT), demonstrating that solvation can remarkably change the geometries of such systems. The electronic excitation energies are then computed with time-dependent DFT (TD-DFT), second-order N-electron valence state perturbation theory (NEVPT2), and contracted spin–orbit configuration interaction (c-SOCI), showing (i) that the SOC must be at play to obtain excitation energies in the right energy domain and (ii) that the quantum chemical calculations point toward x = 4, i.e., toward the [Po(OH)Cl4]− and [PoCl6]2– complexes.
Cited By
This article is cited by 5 publications.
- Jin Y. Chen, Emmy Rodriguez, Huanhuan Jiang, Kunpeng Chen, Alexander Frie, Haofei Zhang, Roya Bahreini, Ying-Hsuan Lin. Time-Dependent Density Functional Theory Investigation of the UV–Vis Spectra of Organonitrogen Chromophores in Brown Carbon. ACS Earth and Space Chemistry 2020, 4 (2) , 311-320. https://doi.org/10.1021/acsearthspacechem.9b00328
- Nadiya Zhutova, Florent Réal, Eric Renault, Valérie Vallet, Rémi Maurice. Excited states of polonium( iv ): electron correlation and spin–orbit coupling in the Po 4+ free ion and in the bare and solvated [PoCl 5 ] − and [PoCl 6 ] 2− complexes. Physical Chemistry Chemical Physics 2023, 25 (36) , 24603-24612. https://doi.org/10.1039/D3CP03317A
- Hamissou Mohaman, Steffen Happel, Gilles Montavon, Nicolas Galland. Tailoring an efficient computational methodology for studying ligand interactions with heavy radiometals in solution: the case of radium. New Journal of Chemistry 2023, 47 (27) , 12914-12925. https://doi.org/10.1039/D3NJ02103C
- Nadiya Zhutova, Florent Réal, Valérie Vallet, Rémi Maurice. Geometries, interaction energies and bonding in [Po(H 2 O) n ] 4+ and [PoCl n ] 4− n complexes. Physical Chemistry Chemical Physics 2022, 24 (42) , 26180-26189. https://doi.org/10.1039/D2CP04001H
- Ali Younes, Cyrille Alliot, Jafar Sunga Ali, Anne-Cécile Bonraisin, Marcel Mokili, Steffen Happel, Aude Bombard, Ferid Haddad, Gilles Montavon. Production of polonium from bismuth and purification using TBP resin and Sr resin. Journal of Radioanalytical and Nuclear Chemistry 2020, 324 (2) , 823-828. https://doi.org/10.1007/s10967-020-07109-5