Preparation and Characterization of an Oxoporphinatochromium(V) Complex

Oxometalloporphyrin species have been implicated as intermediates in the catalytic cycles of peroxidases such as horse radish peroxidase and monooxygenases such as cytochrome P-450. Although simple oxometalloporphyrin complexes of vanadium(IV) and molybdenum(V) are known, these compounds do not undergo the oxygen-transfer reactions characteristic of these enzymes. Recently, we reported that chlorotetraphenylporphinatoiron(III) was capable of catalying oxygen transfer from iodosylbenzene to saturated and unsaturated hydrocarbons and suggested the possible intermediacy of an oxoporphinatoiron(V) complex in this reaction. We and others have reported the observation of spectral transients associated with this reaction, but it has not yet been possible to choose among several possible formulations for this intermediate.