The solvent effect on the electro-oxidation of 1,4-phenylenediamine. The influence of the solvent reorientation dynamics on the one-electron transfer rate
Abstract
The one-electron electro-oxidation of 1,4-phenylenediamine to the corresponding radical cation has been studied by cyclic voltammetry at a Pt electrode in perchlorate solutions in a wide range of aprotic and hydrogen-bonded solvents. A linear relationship between the redox potential of this system and the donor number of a given solvent has been found. It has been shown that the dynamics of solvent reorientation strongly affects the heterogeneous electron transfer rate in the studied case: an almost linear relationship between the standard rate constant and the reciprocal of the longitudinal dielectric relaxation time of a given solvent has been found. It has been suggested that the solvent dynamics affects the rate of the analogous homogeneous electron-transfer reaction.