Density functional study on the mechanism of the vanadium-catalyzed oxidation of sulfides by hydrogen peroxide

A computational study with the Becke3LYP method is carried out on the mechanism of the reaction of complexes V(O)(L)(OOH) and V(O)(LH)(OO) (L = O(CH)(3)N(CH2)(2)O) with CH3S-SCH3, a system that stands as a model for experimental systems where the metal complex contains larger chelating Schiff bases and the substrate is bis(tert-butyl) disulfide. The different possible isomers of both the hydroperoxo V(O)(L)(OOH) and the peroxo V(O)(LH)(OO) forms of the catalyst are explored, and the reactivity of the most stable among them with the dimethyl disulfide substrate is studied through location of the corresponding transition states. A large variety of reactive paths happen to exist, though in all cases the reaction takes place through a direct transfer process, with the simultaneous formation of the S-O bond and breaking of the O-O bond being the rate-limiting step.