Mild Metal-Catalyzed C–H Activation

Alternative Synthesis for Oxoiron(IV) Species

High-valent iron-oxo porphyrin species (compound I (Cpd I) and compound II (Cpd II)) are invoked as key oxidizing intermediates in the catalytic cycles of a broad spectrum of heme enzymes and are important reactive species in catalysis. In heme enzymes, these species are formed from dioxygen, whereas high-energy oxidants are typically required to prepare their synthetic analogues.

 Our new approach for generation and study of synthetic Cpd I and II analogues is through the one or two electron oxidation of μ-oxo heme/Cu complexes, with mild oxidants. These synthetic heme-copper oxidase model complexes, possess many interesting structural and reactivity properties that make them promising precursors for the generation of synthetic high-valent iron-oxo porphyrins. The primary objective of this project is to tune the electron density residing on the μ-oxo moiety through modification of the copper coordination environment, axial ligands, and substituents on the porphyrin ring, thereby allowing for more accessible high-valent iron oxo species for synthetic applications and fundamental characterization. We also use laser flash photolysis to prepare synthetic Cpd I or II analogues from the μ-oxo heme/Cu compounds.