Bimolecular homolytic substitution (SH2) reactions with hydrogen atoms. Time-resolved electron spin resonance detection in the pulse radiolysis of a-(methylthio)acetamide

Pulse radiolysis of aqueous solutions of α-(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, SH2, of the acetamide radical fragment by a H atom is the most likely formation pathway.