Tuning the Redox Properties of a Nonheme Iron(III)-Peroxo Complex Binding Redox-Inactive Zinc Ions by Water Molecules
- 주제(키워드) bioinorganic chemistry , metal-oxygen intermediates , oxygen-evolving complexes , redox reactions , water oxidation
- 등재 SCIE, SCOPUS
- 발행기관 Wiley-VCH Verlag
- 발행년도 2015
- 총서유형 Journal
- URI http://www.dcollection.net/handler/ewha/000000118447
- 본문언어 영어
- Published As http://dx.doi.org/10.1002/chem.201502143
- 저작권 이화여자대학교 논문은 저작권에 의해 보호받습니다.
초록/요약
Redox-inactive metal ions play important roles in tuning chemical properties of metal-oxygen intermediates. Herein we report 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-(O<inf>2</inf>)-Zn(CF<inf>3</inf>SO<inf>3</inf>)<inf>2</inf> (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-(O<inf>2</inf>)-Zn(CF<inf>3</inf>SO<inf>3</inf>)<inf>2</inf>-(OH<inf>2</inf>)<inf>2</inf> [1-Zn2+-(OH<inf>2</inf>)<inf>2</inf>], releases the O<inf>2</inf> 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+-(OH<inf>2</inf>)<inf>2</inf>. 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. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
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