In situ UV-Vis spectroelectrochemical evidence of an EC mechanism in the electrooxidation of N-methylaniline

The anodic oxidation of N-methylaniline (NMA) on optically transparent electrodes was studied with in situ UV-Vis spectroscopy. An absorbance band at lambda(max)=443 nm was ascribed to the formation of an intermediate species formed during electrolysis. The intermediate was found to react with solution NF IA, forming a soluble polymer, which shows an absorbance band at lambda(max)=750 nm. Thus, an EC mechanism of NMA electrooxidation was confirmed. It was concluded, that the presence of an alkyl chain at the aniline nitrogen stabilizes the intermediate and enables its detection by simple spectroelectrochemical technique on a minute lime scale. Anodic oxidation of NMA on ITO electrode, covered with a thin layer of polyaniline, was found to proceed faster than on a bare electrode. A copolymerisation of NMA and aniline was showed to proceed.