ELECTRON-TRANSFER MEDIATION CHARACTERISTICS OF CONDUCTING POLYMER-FILMS OF 4(5-CHLORO-2-PYRIDYL)-1,3-DIAMINOBENZENE COBALT COMPLEX

Stable electroactive polymer films of cobalt complex of 4(5-chloro-2-pyridylazo)-1.3-diaminobenzene (abbreviated as PCoL2) were prepared on glassy carbon electrodes by the oxidative polymerization of the complex in acetonitrile. Two pairs of reversible redox peaks for PCoL2 films were observed. The first pair is attributed to the electroactivity of the skeleton of the polymer and the other is attributed to the redox processes of the Co3+/2+ couple. The surface concentration of the electroactive Co sites was found to increase with increasing the film thickness. Mediation of reduction of [Fe(CN)6]3- by PCoL2 films was investigated by steady state measurements. The rate of the mediated reaction was found to be controlled by the rate of the charge propagation within the film & the rate of diffusion of the substrate through the film beside the rate of diffusion of the substrate to the electrode. Thin films were found to be potentially more efficient for the mediation than thicker films.