Oxysulfur Compounds Derived from Dimethyl Disulfide: An ab Initio Study

Abstract

The optimized geometries of oxysulfur compounds derived from dimethyl disulfide were calculated at the MP2/6-31G* level, and the relative energies of isomers in the CH3S2OCH3, CH3S2O2CH3, CH3S2O3CH3, and CH3S2O4CH3 series were compared. All these derivatives are characterized by long S−S bonds or long sulfenyl or sulfinyl S−O bonds for sulfur−oxygen-bridged isomers. According to the geometrical parameters calculated for vic-disulfoxide 4RR in the CH3S2O2CH3 series, this compound is better described as two interacting sulfinyl radicals, and the obtained results substantiate the experimental scheme proposed by Clennan28 for the intramolecular singlet oxygen addition on disulfides. The UV spectra of all these isomers were evaluated at a standard ab initio level: despite underestimated wavelengths, their evolution (wavelengths and molar extinction coefficients) is consistent with experiment and indicates a strong influence of the σS-S,nS → σ*S-S transition for sulfur−sulfur-bridged isomers and of nS,nO → σ*S...