title: Dioxygen binding to complexes with Fe(II)2(mu-OH)2 cores: steric control of activation barriers and O2-adduct formation.
abstract: A series of complexes with [Fe(II)(2)(mu-OH)(2)] cores has been synthesized with N3 and N4 ligands and structurally characterized to serve as models for nonheme diiron(II) sites in enzymes that bind and activate O(2). These complexes react with O(2) in solution via bimolecular rate-limiting steps that differ in rate by 10(3)-fold, depending on ligand denticity and steric hindrance near the diiron center. Low-temperature trapping of a (mu-oxo)(mu-1,2-peroxo)diiron(III) intermediate after O(2) binding requires sufficient steric hindrance around the diiron center and the loss of a proton (presumably that of a hydroxo bridge or a yet unobserved hydroperoxo intermediate). The relative stability of these and other (mu-1,2-peroxo)diiron(III) intermediates suggests that these species may not be on the direct pathway for dioxygen activation.
authors.affiliation: Department of Chemistry, Tufts University, 62 Talbot Avenue, Medford, Massachusetts 02155, USA.
authors.forename: Sergey V
authors.initials: SV
authors.lastname: Kryatov
authors.forename: Sonia
authors.initials: S
authors.lastname: Taktak
authors.forename: Ivan V
authors.initials: IV
authors.lastname: Korendovych
authors.forename: Elena V
authors.initials: EV
authors.lastname: Rybak-Akimova
authors.forename: József
authors.initials: J
authors.lastname: Kaizer
authors.forename: Stéphane
authors.initials: S
authors.lastname: Torelli
authors.forename: Xiaopeng
authors.initials: X
authors.lastname: Shan
authors.forename: Sanjay
authors.initials: S
authors.lastname: Mandal
authors.forename: Vicki L
authors.initials: VL
authors.lastname: MacMurdo
authors.forename: Antoni
authors.initials: A
authors.lastname: Mairata i Payeras
authors.forename: Lawrence
authors.initials: L
authors.lastname: Que
mesh_terms: D018360:Crystallography, X-Ray; D004563:Electrochemistry; D005296:Ferrous Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D008024:Ligands; D008956:Models, Chemical; D008968:Molecular Conformation; D015394:Molecular Structure; D010100:Oxygen / Q000737:chemistry*
chemical_list: D005296:Ferrous Compounds; D008024:Ligands; D010100:Oxygen