title: 1H-ENDOR evidence for a hydrogen-bonding interaction that modulates the reactivity of a nonheme Fe(IV)═O unit.
abstract: We report that a novel use of 35 GHz (1)H-ENDOR spectroscopy establishes the presence in 1 of an Fe(IV)═O···H-O-Fe(III) hydrogen bond predicted by density functional theory computations to generate a six-membered-ring core for 1. The hydrogen bond rationalizes the difference in the C-H bond cleavage reactivity between 1 and 4(OCH(3)) (where a CH(3)O group has replaced the HO on the Fe(III) site). This result substantiates the seemingly paradoxical conclusion that the nonheme Fe(IV)═O unit of 1 not only has the electrophilic character required for H-atom abstraction but also retains sufficient nucleophilic character to accept a hydrogen bond from the Fe(III)-OH unit.
authors.affiliation: Department of Chemistry, Northwestern University, Evanston, Illinois 60208-3113, USA.
authors.forename: Muralidharan
authors.initials: M
authors.lastname: Shanmugam
authors.forename: Genqiang
authors.initials: G
authors.lastname: Xue
authors.forename: Lawrence
authors.initials: L
authors.lastname: Que
authors.forename: Brian M
authors.initials: BM
authors.lastname: Hoffman
mesh_terms: D004578:Electron Spin Resonance Spectroscopy / Q000379:methods*; D005290:Ferric Compounds / Q000737:chemistry*; D006860:Hydrogen Bonding; D058085:Iron Compounds / Q000737:chemistry*; D008958:Models, Molecular; D010100:Oxygen / Q000737:chemistry*
chemical_list: D005290:Ferric Compounds; D058085:Iron Compounds; D010100:Oxygen