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Physical Chemistry Chemical Physics 13 (2011) 14984-14992
Assessment of an effective quasirelativistic methodology designed to study astatine chemistry in aqueous solution
J. Champion1, M. Seydou2, A. Sabatie-Gogova1, E. Renault2, Gilles Montavon1, N. Galland2

A cost-effective computational methodology designed to study astatine (At) chemistry in aqueous solution has been established. It is based on two-component spin-orbit density functional theory calculations and solvation calculations using the conductor-like polarizable continuum model in conjunction with specific astatine cavities. Theoretical calculations are confronted with experimental data measured for complexation reactions between metallic forms of astatine (At+ and AtO+) and inorganic ligands (Cl-, Br- and SCN-). For each reaction, both 1:1 and 1:2 complexes are evidenced. The experimental trends regarding the thermodynamic constants (K) can be reproduced qualitatively and quantitatively. The mean signed error on computed Log K values is -0.4, which corresponds to a mean signed error smaller than 1 kcal mol-1 on free energies of reaction. Theoretical investigations show that the reactivity of cationic species of astatine is highly sensitive to spin-orbit coupling and solvent effects. At the moment, the presented computational methodology appears to be the only tool to gain an insight into astatine chemistry at a molecular level.
1 :  SUBATECH - Laboratoire SUBATECH Nantes
2 :  CEISAM - Chimie Et Interdisciplinarité : Synthèse, Analyse, Modélisation