Spin state tuning of non-heme iron-catalyzed hydrocarbon oxidations: participation of FeIII–OOH and FeVO intermediatesBased on the presentation given at Dalton Discussion No. 4, 10–13th January 2002, Kloster Banz, Germany.

Abstract

We have found a family of non-heme iron complexes [FeII(L)(CH3CN)2] (L = tetradentate pyridine containing ligand) with cis labile sites that catalyze highly stereoselective hydrocarbon oxidations using H2O2 as oxidant. The hydrocarbon oxidation reactivity patterns of this family of catalysts divide them into two subgroups: Category A catalysts which carry out highly stereoselective alkane hydroxylation, olefin epoxidation, and olefin cis-dihydroxylation via low-spin FeIII–OOH, FeVO intermediates and Category B catalysts which form high-spin FeIII–OOH intermediates and strongly favor olefin cis-dihydroxylation in which both diol oxygen atoms derive from H2O2. 6-Methyl substituents on the ligands play an important role in tuning the spin states of the iron centers to afford a family of non-heme iron complexes that catalyze a remarkable array of hydrocarbon oxidation reactions.