Reduction Potentials and Kinetics of β-Fragmentation Reactions of 4-Substituted Benzoylthiyl Radicals

• Published in: The journal of physical chemistry. A, Molecules, spectroscopy, kinetics, environment, & general theory Vol. 104; no. 37; pp. 8524 - 8526
• Main Authors: Zhao, Rong, Lind, Johan, Merényi, Gábor, Jonsson, Mats, Eriksen, Trygve E
• Format: Journal Article
• Language: English
• Published: American Chemical Society 21-09-2000
• Subjects: acids; chemistry; electron
• ISSN: 1089-5639; 1520-5215; 1520-5215
• DOI: 10.1021/jp001444k

By means of pulse radiolysis, the one-electron reduction potentials of 4-substituted benzoylthiolates E°(4-XPhC(O)S•/4-XPhC(O)S-), where X is CH3, CH3O, CF3, and CN, were measured in aqueous solutions. The kinetics of β-fragmentation reactions of the 4-XPhC(O)S• radicals to form the corresponding 4-XPh• radicals and COS (i.e., 4-XPhC(O)S• → 4-XPh• + COS) were also determined. The pK as of the corresponding acids (4-XPhC(O)SH) were measured by a spectrophotometric method. Thus, the values of E°(4-XPhC(O)S•, H+/4-XPhC(O)SH) and the S−H bond strength of the 4-XPhC(O)S−H were calculated. The substituent effects on the redox potential, the pK a, and the kinetics of their β-fragmentation reactions were examined.