ELECTROCHEMICAL AND SPECTROELECTROCHEMICAL STUDIES ON METALLOPHTHALOCYANINE-OXYGEN INTERACTIONS IN NONAQUEOUS SOLUTIONS

Redox chemistries of cobalt(II) and iron(II) phthalocyanines, as well as interactions of the reduced phthalocyanines with oxygen, have been studied using spectroelectrochemical and other transient electrochemic al techniques in nonaqueous solutions including pyridine, dimethylsulf oxide, and dichloromethane. Results indicate that metal-ligand charge transfer (MLCT) bands are affected significantly by solvent molecules. The broad MLCT band observed from reduced cobalt phthalocyanine in th e spectral region between the Soret and Q bands is shown to consist of two different transitions, generated at the first and second reductio n potentials, respectively. The phthalocyanines undergo quasi-reversib le electron transfer reactions as characterized by electrode kinetic p arameters. The results of studies on interactions of reduced cobalt ph thalocyanine with oxygen indicate that the catalytic activities of pht halocyanines are achieved through a conventional regenerative catalyti c mechanism (EC').