THERMOCHEMISTRY OF SULFENIC ESTERS (RSOR') - NOT JUST ANOTHER PRETTY PEROXIDE

A computational study on the thermochemistry of several simple sulfeni c acids (RSOH) and esters (RSOR') is reported. The enthalpies of R-S, S-O, and O-R' homolytic cleavage are calculated at the G2 level of the ory and compared to related peroxides and disulfides. Less expensive B 3LYP calculations were unsatisfactory. When R and R' are both alkyl, t he O-C bond is expected to be the weakest in the molecule; for CH3SOCH 3, C-S, S-O, and O-C bond dissociation enthalpies of 67, 64, and 49 kc al/mol are predicted by G2. Compared to peroxides, sulfenic esters are predicted to have weaker O-C bonds and S-O bonds that are stronger th an the analogous O-O bonds. The C-S bonds of sulfenic esters are predi cted to be somewhat stronger than those of disulfides. A rationalizati on is given for the observation that radical stabilization is greater for RSO. than ROO. RSS., or ROS..