Voltammetry in Benzene and Chlorobenzene. The Behaviour of Ions of Aromatic Compounds in Nonpolar Media.

Abstract

By employing minute working electrodes, it was found possible to measure well defined redox potentials of aromatic hydrocarbons in the nonpolar solvents, benzene and chlorobenzene. Both so\vents were found to have large accessible anodic and cathodic potential ranges. Anions appear to be exceptionally stable in benzene, the reversible formation of a trianion-radical being observed. Both the anion radical and dianion of perylene were formed reversibly under cyclic voltammetric conditions in benzene while the cation radical was found to adsorb strongly to the electrode. The latter behaviour was rationalized in terms of stronger ion-pairing between the anions and supporting electrolyte cations taking place stabilizing the anions while similar strong interactions involving the cation radicals are absent. Due to the inertness of chlorobenzene, its wide voltammetric potential range, and the ready solubility of tetrabutylammonium salts in the solvent, chlorobenzene was suggested to be an excellent solvent for the study of reversible oxidation and reduction of aromatic compounds.