EPR studies of the copper-catalysed oxidation of thiols with peroxides

EPR spectroscopy has been employed to monitor the reactions of CuII and the formation of organic radicals in the copper-catalysed oxidation of thiols to disulfides in the presence of oxygen and peroxides. Reaction of CuII with RSH gives CuI and disulfide (a process whose stoichiometry is 1:1 in certain solvents), which is followed by electron transfer to the peroxide to give CuII and, for example, HO˙(from H2O2) and ButO˙(from ButO2H) which convert more thiol into disulfide. EPR and UV–VIS spectroscopy allow the kinetic parameters of these reactions to be determined in N,N-dimethylformamide (DMF).