OXO- AND HYDROXO-BRIDGED HEME-COPPER ASSEMBLIES FORMED FROM ACID-BASE OR METAL-DIOXYGEN CHEMISTRY

The iron−copper dinuclear active site in heme-copper oxidases (e.g., cyctochrome c oxidase) has spurred the development of the inorganic chemistry of bridged heme-copper complexes, including species possessing (porphyrinate)FeIII−O(H)−CuII−L moieties. We describe here the synthesis, by two routes, of [(F8TPP)FeIII−O−CuII(MePY2)]+ (5) {F8TPP = tetrakis(2,6-difluorophenyl)porphyrinate; MePY2 = N,N-bis[2-(2-pyridyl)ethyl]methylamine}. First, 5-(CF3SO3) was generated by reaction of [(MePY2)CuII](CF3SO3)2 (3-(CF3SO3)2) and [(F8TPP)FeIII−OH] (4) with triethylamine in THF or CH3CN in 65−70% yield. The complex was also prepared by reduction of O2 by a 1:1 mixture of copper(I) and iron(II) complexes, [(MePY2)CuI(CH3CN)](BArF) (1-(BArF)) (BArF = tetrakis(3,5-bis-trifluoromethylphenyl)borate) and (F8TPP)FeII (2) in O2-saturated THF or acetone, at −80 °C with subsequent warming to room temperature. Preliminary stopped-flow kinetics on the O2 reaction with the 1:1 mixture show the formation of at least two intermediat...