title: Superoxo, mu-peroxo, and mu-oxo complexes from heme/O2 and heme-Cu/O2 reactivity: copper ligand influences in cytochrome c oxidase models.
abstract: The O(2)-reaction chemistry of 1:1 mixtures of (F(8))Fe(II) (1; F(8) = tetrakis(2,6-diflurorophenyl)porphyrinate) and [(L(Me(2))N)Cu(I)](+) (2; L(Me(2))N = N,N-bis(2-[2-(N',N'-4-dimethylamino)pyridyl]ethyl)methylamine) is described, to model aspects of the chemistry occurring in cytochrome c oxidase. Spectroscopic investigations, along with stopped-flow kinetics, reveal that low-temperature oxygenation of 1/2 leads to rapid formation of a heme-superoxo species (F(8))Fe(III)-(O(2)(-)) (3), whether or not 2 is present. Complex 3 subsequently reacts with 2 to form [(F(8))Fe(III)-(O(2)(2-))-Cu(II)(L(Me(2))N)](+) (4), which thermally converts to [(F(8))Fe(III)-(O)-Cu(II)(L(Me(2))N)](+) (5), which has an unusually bent (Fe-O-Cu) bond moiety. Tridentate chelation, compared with tetradentate, is shown to dramatically lower the nu(O-O) values observed in 4 and give rise to the novel structural features in 5.
authors.affiliation: Department of Chemistry, Johns Hopkins University, Baltimore, MD 21218, USA.
authors.forename: Eunsuk
authors.initials: E
authors.lastname: Kim
authors.forename: Matthew E
authors.initials: ME
authors.lastname: Helton
authors.forename: Ian M
authors.initials: IM
authors.lastname: Wasser
authors.forename: Kenneth D
authors.initials: KD
authors.lastname: Karlin
authors.forename: Shen
authors.initials: S
authors.lastname: Lu
authors.forename: Hong-Wei
authors.initials: HW
authors.lastname: Huang
authors.forename: Pierre
authors.initials: P
authors.lastname: Moenne-Loccoz
authors.forename: Christopher D
authors.initials: CD
authors.lastname: Incarvito
authors.forename: Arnold L
authors.initials: AL
authors.lastname: Rheingold
authors.forename: Marcus
authors.initials: M
authors.lastname: Honecker
authors.forename: Susan
authors.initials: S
authors.lastname: Kaderli
authors.forename: Andreas D
authors.initials: AD
authors.lastname: Zuberbuhler
mesh_terms: D003576:Electron Transport Complex IV / Q000737:chemistry* / Q000378:metabolism*; D006418:Heme / Q000378:metabolism*; D008958:Models, Molecular; D010100:Oxygen / Q000378:metabolism*; D011485:Protein Binding; D011487:Protein Conformation
chemical_list: D006418:Heme; D003576:Electron Transport Complex IV; D010100:Oxygen