ELECTROCHEMISTRY OF CONDUCTING POLYPYRROLE FILMS CONTAINING COBALT PORPHYRIN

The electrochemical polymerisation of pyrrole-substituted cobalt tetraphenylporphine complex on a vitreous carbon electrode has been performed in acetonitrile+tetrabutylammonium tetrafluoroborate solution. The redox properties of the film have been examined by cyclic voltammetry and compared to those of cobalt-porphyrin monomer in solution. Voltammograms of these films exhibit a reversible process for the Co(II)/Co(I) reaction at a formal potential of -0.87 V/SCE. The cobalt-porphyrin content of the films has been estimated by cyclic voltammetry, and the conductivity of the polymers has been assessed by studying well-known electrochemical processes in solution at these modified electrodes. Thus, it appears that thick polyporphyrin films act as insulators in low potential range E < -1 V/SCE. Copolymerisation of the pyrrole-substituted cobalt porphyrin with pyrrole and 3-(pyrrol-1-ylmethyl)pyridine has been achieved. No improvement of the electrochemical properties has been noted for the copolymers obtained. We have also proved that interchain complexation reaction of the cobalt(III) sites occurs by the pyridine moieties of the copolymer films. © 1990.