Voltammetric, Chronocoulometric, and Spectroelectrochemical Studies of Electropolymerized Films Based on Cu(II/I)−4,9,16,23-Tetraaminophthalocyanine

Abstract

Several observations from voltammetric, spectroelectrochemical, and chronocoulometric studies of thin films obtained by electropolymerization of Cu(II/I)-4,9,16,23-tetraaminophthalocyanines are reported. Glassy carbon and indium tin oxide (ITO) surfaces were used as working electrodes. Cyclic voltammograms recorded during electropolymerization are interpreted as well as cyclic voltammograms for characterization of the films in aqueous solutions of NaClO 4 and dimethyl sulfoxide (DMSO). The voltammetric behavior and chronocoulometric estimation of relative charge-transfer diffusion data point to quasireversible thin-layer electrochemistry with faster reduction at low surface coverage but faster oxidation at relatively higher surface coverage in NaClO 4 . The same was observed during electropolymerization: a shift to more negative potentials of the cathodic peak for [Cu 2+ , Pc 2- ] + e - → [Cu + , Pc 2- ] - can be seen with increasing surface coverage (Pc = phthalocyanine moiety). In DMSO, however, the oxidation step is faster. Spectra of parent compounds in solution, electropolymerization on ITO, and spectroelectrochemical studies with the electrodeposited films on ITO are discussed and related to the electrochemical information collected using glassy carbon electrodes.