Heme-copper oxidases facilitate the four-electron four-proton reduction of dioxygen to water; this reaction couples to the biological ATP production. Our research goal is to contribute to a fundamental understanding of O2-reactivity at heme/Cu centers via examination of model systems. The synthesis of reduced (heme)FeII…CuI(ligand) ensembles is described; their reactions with O2 gives high-spin (iron) peroxo-bridged FeIII-(O22–)-CuII(ligand) complexes whose structure depends on the Cu-chelating ligand. Conversion to low-spin analogues occurs by addition of an heme axial-ligand (B) giving (B)FeIII-(m-1,2-O22–)-CuII(ligand) peroxo species. The nature of the Cu-ligation dictates the physical properties and subsequent reactivity of these assemblies. We also describe reactions with proton-electron sources (e.g., acids-reductants, catechols) which effect differing reactivity, such as metal-O bond cleavage releasing hydrogen peroxide and biomimetic reductive O-O cleavage.

Proton-electron promoted reductive O-O cleavage within synthetic heme-O2-copper assemblies

255th National Meeting (2018)

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