Electrochemically driven introduction of copper ions into the ring of 5,10,15,20-tetraphenyl-21H, 23H-porphyrin mechanically attached as solid microparticles to a graphite electrode

Abstract

Upon cyclic electrochemical polarization, traces of 5,10,15,20-tetraphenyl-21H,23H-porphyrin (H 2 TPP), which have been mechanically transferred to the surface of a paraffin-impregnated graphite electrode, incorporate copper ions from aqueous solution into the porphyrin ring to form CuTPP . The mechanism of formation of copper porphyrin and the catalytic action of the latter on the electroreduction of oxygen were studied by cyclic voltammetry and square-wave voltammetry. In solid CuTPP the Cu II / Cu I system is electrochemically active according to the following insertion electrochemical reaction: [Formula: see text]. When the CuTPP is dissolved in organic solvents, the central copper ion does not show any electrochemical activity in the accessible potential range.