title: A high-valent iron-oxo corrolazine activates C-H bonds via hydrogen-atom transfer.
abstract: Oxidation of the Fe(III) complex (TBP(8)Cz)Fe(III) [TBP(8)Cz = octakis(4-tert-butylphenyl)corrolazinate] with O-atom transfer oxidants under a variety of conditions gives the reactive high-valent Fe(O) complex (TBP(8)Cz(+•))Fe(IV)(O) (2). The solution state structure of 2 was characterized by XAS [d(Fe-O) = 1.64 Å]. This complex is competent to oxidize a range of C-H substrates. Product analyses and kinetic data show that these reactions occur via rate-determining hydrogen-atom transfer (HAT), with a linear correlation for log k versus BDE(C-H), and the following activation parameters for xanthene (Xn) substrate: ΔH(++) = 12.7 ± 0.8 kcal mol(-1), ΔS(++) = -9 ± 3 cal K(-1) mol(-1), and KIE = 5.7. Rebound hydroxylation versus radical dimerization for Xn is favored by lowering the reaction temperature. These findings provide insights into the factors that control the intrinsic reactivity of Compound I heme analogues.
authors.affiliation: Department of Chemistry, Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, USA.
authors.forename: Kevin
authors.initials: K
authors.lastname: Cho
authors.forename: Pannee
authors.initials: P
authors.lastname: Leeladee
authors.forename: Amanda J
authors.initials: AJ
authors.lastname: McGown
authors.forename: Serena
authors.initials: S
authors.lastname: DeBeer
authors.forename: David P
authors.initials: DP
authors.lastname: Goldberg
mesh_terms: D019281:Dimerization; D005290:Ferric Compounds / Q000737:chemistry*; D006859:Hydrogen / Q000737:chemistry; D006900:Hydroxylation; D007700:Kinetics; D008958:Models, Molecular; D016877:Oxidants / Q000737:chemistry*; D010084:Oxidation-Reduction; D010100:Oxygen / Q000737:chemistry*; D013696:Temperature; D014966:Xanthenes / Q000737:chemistry
chemical_list: D005290:Ferric Compounds; D016877:Oxidants; D014966:Xanthenes; D006859:Hydrogen; D010100:Oxygen