21 May 2007
Prof. Sason Shaik (Hebrew University, Jerusalem, Israel)
A Tale of Two States: From Iron Oxo Diatomic to Cytochrome P450 and Other Oxidation Catalysts
The talk will describe the phenomenon of two-state or multi-state reactivity (TSR/MSR) in high-valent metal-oxo reagents, projecting its wide-ranging applicability starting from the bare diatomic species, through the reagents made by Que and collaborators, to the Mn(V)-oxo susbstituted polyoxometalate, all the way to Compound I species of cytochrome P450 and other heme enzymes. The paper shows how the TSR/MSR behaviors of all these variegated species derive from a simple set of electronic structure principles. Controversial experimental trends concerning radical lifetimes and product isotope effect will be reconciled with the TSR/MSR picture. Diagnostic mechanistic probes will be proposed for the TSR/MSR scenario, based on kinetic isotope effect, stereochemical studies, and magnetic- and electric-field effects.