Oxygenation reactions of cytochrome oxidase models. Evidence for hematin formation in mononuclear and heterobinuclear complexes

Controlled potential electrolysis, chemical reduction, or synthesis is used to prepare the FeIII/CuI and FeII/CuI complexes of meso-tetra-αααα-o-(nicotinami-dophenyl)porphyrin; on exposure to oxygen the Cu-free derivative and the fully reduced heterobinuclear complexes undergo irreversible oxidation to the hematins Fe(P)–OH–(N4) and Fe(P)–OH–Cu(N4)2+, respectively.