Voltammetric behaviour of heterocyclic systems. Pyridyl-substituted benzimidazoles benzoxazoles and benzothiazoles.

The voltammetric properties, measured at a dropping mercury electrode, have been studied for a series of 18 pyridyl-substituted heterocyclic bases [benzimidazoles, benzoxazoles and benzothiazoles]. The corresponding quarternary salts, obtained by reaction with methyl iodide, were also studied. The reduction potential was found to be dependent on the nature of the benzimidazole, benzoxazole or benzothiazole moiety and on its position on the pyridine ring as well as on the presence of a positive charge. The reversibility of the voltammetric waves was found to be function of the system structure. The effects of proton donors on the voltammetric behaviour of the bases was also investigated.