Nonheme Iron Mediated Oxidation of Light Alkanes with Oxone: Characterization of Reactive Oxoiron(IV) Ligand Cation Radical Intermediates by Spectroscopic Studies and DFT Calculations

Publisher： John Wiley & Sons Inc

E-ISSN： 1521-3773|53|3|798-803

ISSN： 1433-7851

Source： ANGEWANDTE CHEMIE INTERNATIONAL EDITION, Vol.53, Iss.3, 2014-01, pp. : 798-803

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Abstract

AbstractThe oxidation of light alkanes that is catalyzed by heme and nonheme iron enzymes is widely proposed to involve highly reactive {FeVO} species or {FeIVO} ligand cation radicals. The identification of these high‐valent iron species and the development of an iron‐catalyzed oxidation of light alkanes under mild conditions are of vital importance. Herein, a combination of tridentate and bidentate ligands was used for the generation of highly reactive nonheme {FeO} species. A method that employs [FeIII(Me3tacn)(Cl‐acac)Cl]+ as a catalyst in the presence of oxone was developed for the oxidation of hydrocarbons, including cyclohexane, propane, and ethane (Me3tacn=1,4,7‐trimethyl‐1,4,7‐triazacyclononane; Cl‐acac=3‐chloro‐acetylacetonate). The complex [FeIII(Tp)2]+ and oxone enabled stoichiometric oxidation of propane and ethane. ESI‐MS, EPR and UV/Vis spectroscopy, 18O labeling experiments, and DFT studies point to [FeIV(Me3tacn)({Cl‐acac}.+)(O)]2+ as the catalytically active species.