STUDY ON THE ELECTROCHEMICAL REDUCTION OF BENZIMIDAZOLE-2-THIONE AND ITS 1-LAUROYL DERIVATIVE IN ORGANIC-SOLVENT

Electrochemical studies of benzimidazole-2-thione and its 1-lauroyl-substituted derivative were carried out in N,N-dimethylformamide (DMF) solvent using a platinum electrode. A variety of electrochemical techniques, such as cyclic voltammetry, coulometry and spectroelectrochemistry (SEC), were employed to clarify the mechanism of the electrode process. The two compounds exhibit a similar redox behaviour under the given conditions. Both display two cathodic peaks in cyclic voltammograms. The overall two-electron transfer in the reduction process is demonstrated by a coulometric experiment. Information about the intermediates formed in the reduction process is derived from SEC. UV-SEC and Raman-SEC show that two successive steps are involved in the reduction process. Dibenzimidazoyl (or its 1-lauroyl-substituted) disulphide is formed in the first step, and the thiol compound is produced in the second step. A reduction mechanism is proposed on this basis. In addition, the reoxidation of the final reduction product is analysed. The reoxidation does not reproduce disulphide, but leads to the formation of a free radical and the corresponding sulphonic acid.