Journal of Electroanalytical Chemistry, Vol.419, No.1, 55-59, 1996
Direct Evidence of Indamine Cation Radicals in the Anodic-Oxidation of Aniline by in-Situ ESR Spectroscopy
The existence of indamine cation radicals in the anodic oxidation of aniline in acidified dimethylsulfoxide (DMSO) is proved by in situ and ex situ ESR spectroscopy. The components of the redox system to form the indamine radicals are studied in DMSO solution by electrochemical in situ ESR spectroscopy, in situ UV-vis spectroscopy and a new triple ESR-UV-vis electrochemistry method. Furthermore, the reaction of benzidine with diphenylamine is investigated for a better understanding of the reaction mechanism. The occurrence of radicals formed in DMSO during electrochemical oxidation is in agreement with the mechanism of the initial stages of electropolymerization of aniline in aqueous solution found by several authors.