title: Redox-inactive metal ions modulate the reactivity and oxygen release of mononuclear non-haem iron(III)-peroxo complexes.
abstract: Redox-inactive metal ions that function as Lewis acids play pivotal roles in modulating the reactivity of oxygen-containing metal complexes and metalloenzymes, such as the oxygen-evolving complex in photosystem II and its small-molecule mimics. Here we report the synthesis and characterization of non-haem iron(III)-peroxo complexes that bind redox-inactive metal ions, (TMC)Fe(III)-(μ,η(2):η(2)-O2)-M(n+) (M(n+) = Sr(2+), Ca(2+), Zn(2+), Lu(3+), Y(3+) and Sc(3+); TMC, 1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane). We demonstrate that the Ca(2+) and Sr(2+) complexes showed similar electrochemical properties and reactivities in one-electron oxidation or reduction reactions. However, the properties and reactivities of complexes formed with stronger Lewis acidities were found to be markedly different. Complexes that contain Ca(2+) or Sr(2+) ions were oxidized by an electron acceptor to release O2, whereas the release of O2 did not occur for complexes that bind stronger Lewis acids. We discuss these results in the light of the functional role of the Ca(2+) ion in the oxidation of water to dioxygen by the oxygen-evolving complex.
authors.affiliation: 1] Department of Chemistry and Nano Science, Department of Bioinspired Science, Center for Biomimetic Systems, Ewha Womans University, Seoul 120-750, Korea [2].
authors.forename: Suhee
authors.initials: S
authors.lastname: Bang
authors.affiliation: 1] Department of Chemistry and Nano Science, Department of Bioinspired Science, Center for Biomimetic Systems, Ewha Womans University, Seoul 120-750, Korea [2].
authors.forename: Yong-Min
authors.initials: YM
authors.lastname: Lee
authors.affiliation: Department of Chemistry and Nano Science, Department of Bioinspired Science, Center for Biomimetic Systems, Ewha Womans University, Seoul 120-750, Korea.
authors.forename: Seungwoo
authors.initials: S
authors.lastname: Hong
authors.affiliation: Department of Chemistry and Nano Science, Department of Bioinspired Science, Center for Biomimetic Systems, Ewha Womans University, Seoul 120-750, Korea.
authors.forename: Kyung-Bin
authors.initials: KB
authors.lastname: Cho
authors.affiliation: Department of Material and Life Science, Graduate School of Engineering, Osaka University and ALCA, Japan Science Technology Agency (JST), Suita, Osaka 565-0871, Japan.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Nishida
authors.affiliation: Department of Chemistry and Nano Science, Department of Bioinspired Science, Center for Biomimetic Systems, Ewha Womans University, Seoul 120-750, Korea.
authors.forename: Mi Sook
authors.initials: MS
authors.lastname: Seo
authors.affiliation: Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
authors.forename: Ritimukta
authors.initials: R
authors.lastname: Sarangi
authors.affiliation: 1] Department of Chemistry and Nano Science, Department of Bioinspired Science, Center for Biomimetic Systems, Ewha Womans University, Seoul 120-750, Korea [2] Department of Material and Life Science, Graduate School of Engineering, Osaka University and ALCA, Japan Science Technology Agency (JST), Suita, Osaka 565-0871, Japan.
authors.forename: Shunichi
authors.initials: S
authors.lastname: Fukuzumi
authors.affiliation: Department of Chemistry and Nano Science, Department of Bioinspired Science, Center for Biomimetic Systems, Ewha Womans University, Seoul 120-750, Korea.
authors.forename: Wonwoo
authors.initials: W
authors.lastname: Nam
mesh_terms: D002118:Calcium / Q000737:chemistry; D056831:Coordination Complexes / Q000737:chemistry*; D055664:Electrochemical Techniques; D004579:Electron Transport; D004583:Electrons; D005290:Ferric Compounds / Q000737:chemistry*; D007477:Ions / Q000737:chemistry; D008670:Metals / Q000737:chemistry*; D010084:Oxidation-Reduction; D010100:Oxygen / Q000737:chemistry*; D013324:Strontium / Q000737:chemistry
chemical_list: D056831:Coordination Complexes; D005290:Ferric Compounds; D007477:Ions; D008670:Metals; D010100:Oxygen; D002118:Calcium; D013324:Strontium