M. Mubarak, D. Peters
Mar 30, 1997
Citations
0
Influential Citations
18
Citations
Journal
Journal of Electroanalytical Chemistry
Abstract
Abstract Cyclic voltammetry and controlled-potential electrolysis, along with quantitative determination of all electrolysis products, have been employed to investigate the electrochemical reduction of a series of mono- and dihalopyridines at glassy carbon cathodes in dimethylformamide containing tetramethylammonium perchlorate. Two reduction waves are observed for 2-bromo-, 3-bromo-, 2-chloro-, 3-chloro-, and 3-iodopyridine; the first wave is due to two-electron cleavage of the carbon-halogen bond, and the second wave is attributable to reduction of pyridine. Bulk electrolyses of these monohalopyridines at potentials corresponding to the first voltammetric wave give pyridine exclusively. Cyclic voltammograms for the reduction of 2,5-dibromo-, 2,6-dibromo-, 3,5-dibromo-, 2,3-dichloro-, 2,5-dichloro-, and 2,6-dichloropyridine exhibit three waves arising from sequential cleavage of the two carbon-halogen bonds as well as reduction of pyridine. Controlled-potential electrolytes of the dihalopyridines at potentials for the first stage of reduction lead to one or two monohalopyridines, whereas electrolyses at potentials corresponding to the second stage of reduction afford only pyridine.