Infrared and Raman spectra of S-methyl thioacetate: toward an understanding of the biochemical reactivity of esters of coenzyme A

Abstract

The IR and Raman spectra of S-methyl thioacetate and CD3C(O)SCH3 were determined. These spectra and those in the literature for S-ethyl thioacetate were assigned. These data together with literature assignments for thioformic acid, thioacetic acid and S-methyl thioformate were used in normal coordinate calculations. The stretching force constant for the carbonyl group of thioesters and thio acids is very similar to that for the carbonyl group of ketones. In addition, the value of the stretching force constant for the C(O).sbd.S bond in thioesters and thioacids indicates that this entity has no double-bond character. The carbonyl group of acetyl coenzyme A is essentially the same as that of a ketone.