Solvation properties of the actinide Ion Th(IV) in DMSO and DMSO:water mixtures through polarizable molecular dynamics

We have studied the solvation of Th(4+) in water, in dimethyl sulfoxide (DMSO), and in their equimolar mixture by using molecular dynamics based on an Amoeba-derived polarizable force field. We have performed an extended structural analysis in order to provide a complete picture of the chemical-physical features of the interaction of Th(4+) with the two solvents in their pure and mixed states. Through our simulations we found that, very likely, the first solvation shell in DMSO is not unlike the one found in pure water and contains 9 solvent molecules. The residence time of first shell of DMSO molecules is however much longer than the residence time of water. For the 1:1 mixture we present computational evidence that both water and DMSO participate in the solvation of Th(4+) with a slight preference for the latter.