ELECTROPOLYMERIZATION AND ELECTROCATALYTIC BEHAVIOR OF ELECTRODES MODIFIED WITH Fe AND NON-METALLED TETRAAMINOPHENYLPORPHYRINS: EFFECT OF THE POSITION OF THE AMINO GROUP ON THE LIGAND

Three monomeric iron and non-metalled tetraaminophenylporphyrins, with amino groups located in defferent positions of the phenyl substituents, were electropolymerized. These processes were carried out through continuous cycling of the potential on glassy carbon electrode surfaces. The aim of the work was to determine the effect of the amino groups’ position on the properties of the modified-electrodes. Phenyl substituents of the porphyrins were not conjugated with the macrocycle. Therefore, their substituents were only expected to modify the electropolymerization and not the potential of the redox metallic couples on the polymer. However, it was found that, when the complex is polymerized, the position of the amino groups greatly changes the potential of the iron couples. Thus, the electrocatalytic activity of the polymer-modified electrode toward the reduction of oxygen strongly depends on the position of amino substituents