A theoretical study on the strength of two-center three-electron bond in (CH3)2S–OH and H2S–OH adducts

Ab initio and DFT investigations on H2S–OH and (CH3)2S–OH adducts have shown that electron correlation is essential for an accurate description of the two-center three-electron S–O bonds in the adducts. Calculations at the BH&HLYP, B3LYP, MP2, and CCSD(T) levels indicate that the S–O bond in the (CH3)2S–OH adduct is considerably stronger and shorter than that in the H2S–OH adduct. Our best estimate for the dissociation enthalpy at 298 K for the S–O bond in the (CH3)2S–OH adduct is 9.0 kcal/mol, which is in satisfactory agreement with experimentally derived values.