Bimolecular homolytic substitution (S(H)2) reactions with hydrogen atoms. time-resolved electron spin resonance detection in the pulse radiolysis of alpha-(methylthio)acetamide

Pulse radiolysis of aqueous solutions of alpha-(methylthio)acetamide produced unexpectedly large quantities of acetamide radicals that were identified by time-resolved electron spin resonance (TRESR) spectroscopy. The pH dependence of the TRESR-measured radical yields, results from selective scavenging reactions, and density functional theory predictions of the reaction thermochemistry prove that bimolecular homolytic substitution, S(H)2, of the acetamide radical fragment by a H atom is the most likely formation pathway.