title: Nuclear Resonance Vibrational Spectroscopic Definition of Peroxy Intermediates in Nonheme Iron Sites.
abstract: FeIII-(hydro)peroxy intermediates have been isolated in two classes of mononuclear nonheme Fe enzymes that are important in bioremediation: the Rieske dioxygenases and the extradiol dioxygenases. The binding mode and protonation state of the peroxide moieties in these intermediates are not well-defined, due to a lack of vibrational structural data. Nuclear resonance vibrational spectroscopy (NRVS) is an important technique for obtaining vibrational information on these and other intermediates, as it is sensitive to all normal modes with Fe displacement. Here, we present the NRVS spectra of side-on FeIII-peroxy and end-on FeIII-hydroperoxy model complexes and assign these spectra using calibrated DFT calculations. We then use DFT calculations to define and understand the changes in the NRVS spectra that arise from protonation and from opening the Fe-O-O angle. This study identifies four spectroscopic handles that will enable definition of the binding mode and protonation state of FeIII-peroxy intermediates in mononuclear nonheme Fe enzymes. These structural differences are important in determining the frontier molecular orbitals available for reactivity.
authors.affiliation: Department of Chemistry, Stanford University , Stanford, California 94305, United States.
authors.forename: Kyle D
authors.initials: KD
authors.lastname: Sutherlin
authors.affiliation: Department of Chemistry, Stanford University , Stanford, California 94305, United States.
authors.forename: Lei V
authors.initials: LV
authors.lastname: Liu
authors.affiliation: Department of Bioinspired Science, Department of Chemistry and Nano Science, Center for Biomimetic Systems, Ewha Womans University , Seoul 120-750, Korea.
authors.forename: Yong-Min
authors.initials: YM
authors.lastname: Lee
authors.affiliation: Department of Chemistry, Stanford University , Stanford, California 94305, United States.
authors.forename: Yeonju
authors.initials: Y
authors.lastname: Kwak
authors.affiliation: SPring-8, JASRI , Hyogo 679-5198, Japan.
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Yoda
authors.affiliation: Research Reactor Institute, Kyoto University , Osaka 590-0494, Japan.
authors.forename: Makina
authors.initials: M
authors.lastname: Saito
authors.affiliation: Research Reactor Institute, Kyoto University , Osaka 590-0494, Japan.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Kurokuzu
authors.affiliation: Research Reactor Institute, Kyoto University , Osaka 590-0494, Japan.
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Kobayashi
authors.affiliation: Research Reactor Institute, Kyoto University , Osaka 590-0494, Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Seto
authors.affiliation: Department of Chemistry, University of Minnesota , Minneapolis, Minnesota 55455, United States.
authors.forename: Lawrence
authors.initials: L
authors.lastname: Que
authors.affiliation: Department of Bioinspired Science, Department of Chemistry and Nano Science, Center for Biomimetic Systems, Ewha Womans University , Seoul 120-750, Korea.
authors.forename: Wonwoo
authors.initials: W
authors.lastname: Nam
authors.affiliation: Department of Chemistry, Stanford University , Stanford, California 94305, United States.|SLAC National Accelerator Laboratory , Menlo Park, California 94025, United States.
authors.forename: Edward I
authors.initials: EI
authors.lastname: Solomon
mesh_terms: D007501:Iron / Q000737:chemistry*; D009942:Organometallic Compounds / Q000737:chemistry*; D011789:Quantum Theory; D013057:Spectrum Analysis; D014732:Vibration
chemical_list: D009942:Organometallic Compounds; D007501:Iron