Further insight into the electropolymerization of porphyrins bearing one to four p-aminophenyl substituents

Tetraarylporphyrins bearing a variable number n of para-NH2 groups (n=1, 2, 3, 4) were used as starting monomers for the controlled formation of porphyrin polymeric films onto Indium Tin Oxide (ITO) slides. The electropolymerization process for each compound was performed by cyclic voltammetry in the 0-1.5 V potential range at a scan rate of 100 mV s− 1, repeating 20 cycles. UV-Vis spectroelectrochemistry allowed the identification of the main molecular species involved in the different oxidation stages, affording crucial information to explain the differences in the formation of the final films, which were pointed out by AFM microscopy. Results indicate that the more the n value increases, the more polymer formation is favored, evidencing that the pattern substitution on the four phenyl groups is decisive for the film growth and the relative morphological features.