title: A diiron(IV) complex that cleaves strong C-H and O-H bonds.
abstract: The controlled cleavage of strong C-H bonds like those of methane poses a significant challenge for chemists. In nature methane is oxidized to methanol by soluble methane monooxygenase via a diiron(IV) intermediate called Q. To model the chemistry of MMO-Q, an oxo-bridged diiron(IV) complex has been generated by electrochemical oxidation and characterized by several spectroscopic methods. This novel species has an Fe(IV/III) redox potential of +1.50 V vs. ferrocene (>2 V vs. NHE), the highest value thus far determined electrochemically for an iron complex. This species is quite an effective oxidant. It can attack C-H bonds as strong as 100 kcal mol(-1) and reacts with cyclohexane a hundred- to a thousand-fold faster than mononuclear Fe(IV)=O complexes of closely related ligands. Strikingly, this species can also cleave the strong O-H bonds of methanol and tert-butanol instead of their weaker C-H bonds, representing the first example of O-H bond activation for iron complexes.
authors.affiliation: Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota, Minneapolis, MN 55455, USA.
authors.forename: Dong
authors.initials: D
authors.lastname: Wang
authors.forename: Erik R
authors.initials: ER
authors.lastname: Farquhar
authors.forename: Audria
authors.initials: A
authors.lastname: Stubna
authors.forename: Eckard
authors.initials: E
authors.lastname: Münck
authors.forename: Lawrence
authors.initials: L
authors.lastname: Que
mesh_terms: D055162:Biocatalysis; D002244:Carbon / Q000737:chemistry*; D056831:Coordination Complexes / Q000737:chemistry*; D018360:Crystallography, X-Ray; D003510:Cyclohexanes / Q000737:chemistry / Q000378:metabolism; D006859:Hydrogen / Q000737:chemistry*; D007501:Iron / Q000737:chemistry*; D000432:Methanol / Q000737:chemistry / Q000378:metabolism; D008968:Molecular Conformation; D010084:Oxidation-Reduction; D010100:Oxygen / Q000737:chemistry*; D010105:Oxygenases / Q000737:chemistry / Q000378:metabolism; D056928:X-Ray Absorption Spectroscopy
chemical_list: D056831:Coordination Complexes; D003510:Cyclohexanes; C506365:Cyclohexane; D002244:Carbon; D006859:Hydrogen; D007501:Iron; D010105:Oxygenases; C021555:methane monooxygenase; D010100:Oxygen; D000432:Methanol