Assessment of an effective quasirelativistic methodology designed to study astatine chemistry in aqueous solution

Julie Champion (1, 2) , Mahamadou Seydou (3, 2, 1) , Andrea Sabatié-Gogova (1) , Eric Renault (2) , Gilles F Montavon (1) , Nicolas Galland (2)

1 SUBATECH - Laboratoire SUBATECH Nantes
2 CEISAM - Chimie Et Interdisciplinarité : Synthèse, Analyse, Modélisation
3 ITODYS (UMR_7086) - Interfaces, Traitements, Organisation et Dynamique des Systèmes

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.

Domaines: Chimie théorique et/ou physique; Radiochimie

Julie Champion, Mahamadou Seydou, Andrea Sabatié-Gogova, Eric Renault, Gilles F Montavon, et al.. Assessment of an effective quasirelativistic methodology designed to study astatine chemistry in aqueous solution. Physical Chemistry Chemical Physics, 2011, 13, pp.14984-14992. ⟨10.1039/C1CP20512A⟩. ⟨in2p3-01586060⟩