title: Spectroscopic and computational studies of (mu-oxo)(mu-1,2-peroxo)diiron(III) complexes of relevance to nonheme diiron oxygenase intermediates.
abstract: With the goal of gaining insight into the structures of peroxo intermediates observed for oxygen-activating nonheme diiron enzymes, a series of metastable synthetic diiron(III)-peroxo complexes with [Fe(III)(2)(mu-O)(mu-1,2-O(2))] cores has been characterized by X-ray absorption and resonance Raman spectroscopies, EXAFS analysis shows that this basic core structure gives rise to an Fe-Fe distance of approximately 3.15 A; the distance is decreased by 0.1 A upon introduction of an additional carboxylate bridge. In corresponding resonance Raman studies, vibrations arising from both the Fe-O-Fe and the Fe-O-O-Fe units can be observed. Importantly a linear correlation can be discerned between the nu(O-O) frequency of a complex and its Fe-Fe distance among the subset of complexes with [Fe(III)(2)(mu-OR)(mu-1,2-O(2))] cores (R = H, alkyl, aryl, or no substituent). These experimental studies are complemented by a normal coordinate analysis and DFT calculations.
authors.affiliation: Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota, 207 Pleasant Street S.E., Minneapolis, Minnesota 55455, USA.
authors.forename: Adam T
authors.initials: AT
authors.lastname: Fiedler
authors.forename: Xiaopeng
authors.initials: X
authors.lastname: Shan
authors.forename: Mark P
authors.initials: MP
authors.lastname: Mehn
authors.forename: József
authors.initials: J
authors.lastname: Kaizer
authors.forename: Stéphane
authors.initials: S
authors.lastname: Torelli
authors.forename: Jonathan R
authors.initials: JR
authors.lastname: Frisch
authors.forename: Masahito
authors.initials: M
authors.lastname: Kodera
authors.forename: Lawrence
authors.initials: L
authors.lastname: Que
mesh_terms: D002384:Catalysis; D018360:Crystallography, X-Ray; D005290:Ferric Compounds / Q000737:chemistry / Q000378:metabolism; D007501:Iron / Q000737:chemistry*; D007700:Kinetics; D008024:Ligands; D015394:Molecular Structure; D010100:Oxygen / Q000737:chemistry; D010105:Oxygenases / Q000737:chemistry* / Q000378:metabolism*; D013052:Spectrometry, X-Ray Emission; D013053:Spectrophotometry; D013059:Spectrum Analysis, Raman; D014732:Vibration
chemical_list: D005290:Ferric Compounds; D008024:Ligands; D007501:Iron; D010105:Oxygenases; D010100:Oxygen