Polarography of aromatic azo compounds. I. Effect of substituents on the electroreduction of azo compounds

Abstract

The polarography of several azo compounds has been investigated, and the electron-attracting, or releasing, ability of the substituents related to their effect on the half step potentials and limiting currents. In the para-substituted azobenzene series, the standard potentials of the electrode reactions bear a linear relationship to the Hammett substituent constants (σp) Groups such as hydroxy, amino, and dimethylamino can cause the number of electrons involved in the polarographic reduction to increase from two to four. Evidence has been obtained to support the theory that an unstable hydrazo intermediate is involved in the reduction of such compounds.