ESR AND POLAROGRAPHY OF NITROAZOLES. 4. POLAROGRAPHIC STUDY OF NITROBENZIMIDAZOLES

Article abstract of DOI:10.1007/BF00506400

The electrochemical reduction of 2-substituted 5(6)-benzimidazoles has been studied with the aid of classical polarography and cyclic voltammetry in acetonitrile.The influence of the substituents in position 2 on the magnitudes of the half-wave potentials of the first stage is exerted by induction and resonance mechanisms with approximately the same contributions, and that on the magnitudes of the half-wave potentials of the second stage predominantly by the resonance mechanism.The posibilities of taking the radical-stabilizing factor ?^. into account in the correlations are discussed.In order to study the 2-substituted 5(6)-nitrobenzimidazole series, their pK_a values in acetonitrile have been determined by potentiometric titration.