A voltammetric study of pyridine-4-aldoxime (PA) at a glassy carbon electrode Error! Reference source not found.in dimethylformamide

Abstract

Abstract The electroreduction of pyridine-4-aldoxime (PA) in DMF has been studied by cyclic voltammetry on a glassy carbon electrode. The behavior observed differs from that found in aqueous buffered solutions, although the same final reduction product, 4-amino-methyl pyridine (AP), is obtained. The overall four-electron reduction process is seen in this aprotic medium as two distinct voltammetric peaks. The first peak is thought to correspond to a monoelectronic transfer that yields a radical anion followed by a fast reaction involving the cleavage of the oxygennitrogen bond. The reaction of the hydroxide ion, generated at this step, with the neutral species of PA is taken as responsible for the change in the reduction mechanism. Thus, the reduction of the anion oxime species, at the potential of the second peak, is proposed. Experiments carried out with different potential programs allow that conclusion. The assignation is also based on results obtained in alkaline media. The addition of a proton donor produces changes, not only to the electroactive species, but also to the overall mechanism, making it similar to that reported in aqueous buffered solutions.