Chemistry of Singlet Oxygen—xxviii*. Steric and Electronic Effects on the Reactivity of Sulfides With Singlet Oxygen

Abstract—The rates of reaction of singlet oxygen with a number of alkyl and aryl sulfides have been determined in CH3OH. The rate for diethylsulfide is 1.71 ± 0.06 × 107M‐1 s‐1. The addition of methyl groups α to the sulfur causes an approximate tenfold decrease in rate for each symmetrical pair. A similar effect is caused by replacement of alkyl by phenyl groups. The rates of substituted thioanisoles correlate well with σ(ρ= ‐1.6). but poorly with EP/2 (half‐peak oxidation potentials). A mechanism involving nucleophilic reaction of the sulfide with oxygen, rather than charge transfer is suggested.