Redox behaviour of phenothiazine and phenazine in organic solvents

The electroreduction of phenazine (PHN) and electro-oxidation of phenothiazine (PHT) in the potential region of the first waves have been examined by polarography and cyclic voltammetry in some organic solvents. Reversible processes , and , were identified in all the solvents under investigations. The large shifts in formal potentials (vs ferrocene/ferricinium internal standard) are interpreted on the basis of Gutmann's donor—acceptor concept for solvent—solute interaction.