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Title: Tuning the Redox Properties of a Nonheme Iron(III)-Peroxo Complex Binding Redox-Inactive Zinc Ions by Water Molecules

Here we report redox-inactive metal ions play important roles in tuning chemical properties of metal–oxygen intermediates. We describe the effect of water molecules on the redox properties of a nonheme iron(III)–peroxo complex binding redox-inactive metal ions. The coordination of two water molecules to a Zn2+ ion in (TMC)FeIII-(O2)-Zn(CF3SO3)2 (1-Zn2+) decreases the Lewis acidity of the Zn2+ ion, resulting in the decrease of the one-electron oxidation and reduction potentials of 1-Zn2+. This further changes the reactivities of 1-Zn2+ in oxidation and reduction reactions; no reaction occurred upon addition of an oxidant (e.g., cerium(IV) ammonium nitrate (CAN)) to 1-Zn2+, whereas 1-Zn2+ coordinating two water molecules, (TMC)FeIII-(O2)-Zn(CF3SO3)2-(OH2)2 [1-Zn2+-(OH2)2], releases the O2 unit in the oxidation reaction. In the reduction reactions, 1-Zn2+ was converted to its corresponding iron(IV)–oxo species upon addition of a reductant (e.g., a ferrocene derivative), whereas such a reaction occurred at a much slower rate in the case of 1-Zn2+-(OH2)2. Finally, the present results provide the first biomimetic example showing that water molecules at the active sites of metalloenzymes may participate in tuning the redox properties of metal–oxygen intermediates.
Authors:
 [1] ;  [1] ;  [2] ;  [1] ;  [1] ;  [1] ;  [3] ;  [4] ;  [1]
  1. Ewha Womans Univ., Seoul (Korea)
  2. Osaka Univ., Suita (Japan); Japan Science and Technology Agency (JST), Suita (Japan). Advanced Low Carbon Technology Research and Development Program (ALCA)
  3. SLAC National Accelerator Lab., Menlo Park, CA (United States). Stanford Synchrotron Radiation Lightsource (SSRL)
  4. Osaka Univ., Suita (Japan); Japan Science and Technology Agency (JST), Suita (Japan). Advanced Low Carbon Technology Research and Development Program (ALCA); Meijo Univ., Nagoya (Japan); Japan Science and Technology Agency (JST), Nagoya (Japan) Advanced Low Carbon Technology Research and Development Program (ALCA) and SENTAN
Publication Date:
Grant/Contract Number:
AC02-76SF0051; NRF-2012R1A3A2048842; NRF-2010-00353; 2013R1A1A2062737
Type:
Accepted Manuscript
Journal Name:
Chemistry - A European Journal
Additional Journal Information:
Journal Volume: 21; Journal Issue: 30; Journal ID: ISSN 0947-6539
Publisher:
ChemPubSoc Europe
Research Org:
SLAC National Accelerator Lab., Menlo Park, CA (United States)
Sponsoring Org:
USDOE; National Research Foundation of Korea (NRF); Japan Society for the Promotion of Science (JSPS)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; bioinorganic chemistry; metal–oxygen intermediates; oxygen-evolving complexes; redox reactions; water oxidation
OSTI Identifier:
1261105