QUANTUM MECHANICAL ASPECTS OF O//2 ACTIVATION BY TRANSITION METAL MACROCYLES: RING-ASSISTED FOUR-ELECTRON REDUCTION.

Iron and cobalt macrocycles have been extensively studied over the past two decades as catalysts for the electrochemical reduction of dioxygen. The importance of such investigations is two-fold. First, the high activity exhibited by some of these compounds has opened the possibility of replacing platinum in fuel cell applications and second, a systematic examination of the electrocatalytic reduction of O//2 by transition metal macrocycles in general may provide further insight into the factors involved in the overall phenomenon of O//2 activation. This work will focus attention on the modification in the mechanism of O//2 reduction induced by changes in the oxidation state of a specific macrocycle. An iron porphyrasine was selected for this study.