How does microhydration impact on structure, spectroscopy and formation of disulfide radical anions? An ab initio investigation on dimethyldisulfide

The effect of microhydration on the one-electron uptake of a prototypical disulfide is examined at the MP2/DZP++ level of theory. After systematic generation of low-lying conformers of dimethyldisulfide–water clusters (DMDS:nH2O, n = 1–5), either neutral or anionic, it is found that their energy ranking is governed by the increasing strength of the three hydrogen bonds involved, namely, water-neutral DMDS bonds, intra-water bonds and water–anionic DMDS bonds. Their optimal values are respectively 3.5, 4.5 and 11.4 kcal/mol. clusion of a limited number of water molecules has a non-negligible impact on structure and UV–Vis absorption of DMDS radical anion. Furthermore, its formation is favored by up to 1.04 eV when explicitly solvated by five water molecules.