A Highly Reactive Chromium(V)-Oxo TAML Cation Radical Complex in Electron Transfer and Oxygen Atom Transfer Reactions
- 주제(키워드) electron transfer , oxygen atom transfer , chromium(V)-oxo complex , redox-inactive metal ion , reorganization energy
- 주제(기타) Chemistry, Physical
- 설명문(일반) [Hong, Young Hyun; Jang, Yuri; Seo, Mi Sook; Lee, Yong-Min; Pandey, Bhawana; Fukuzumi, Shunichi; Nam, Wonwoo] Ewha Womans Univ, Dept Chem & Nano Sci, Seoul 03760, South Korea; [Ezhov, Roman; Pushkar, Yulia] Purdue Univ, Dept Phys & Astron, W Lafayette, IN 47907 USA; [Hong, Seungwoo] Sookmyung Womens Univ, Dept Chem, Seoul 04310, South Korea; [Nam, Wonwoo] Shaanxi Normal Univ, Sch Chem & Chem Engn, Xian, Peoples R China
- 등재 SCIE, SCOPUS
- 발행기관 AMER CHEMICAL SOC
- 발행년도 2021
- 총서유형 Journal
- URI http://www.dcollection.net/handler/ewha/000000181538
- 본문언어 영어
- Published As http://dx.doi.org/10.1021/acscatal.1c00079
초록/요약
We report the synthesis, characterization, and electron-transfer (ET) oxidation reactivity of a chromium(V)-oxo TAML cation radical complex binding Sc3+ ion, {[ Cr-V(O)(TAML(center dot+))]-Sc3+}(3+) (2-Sc). Its precursors, such as [Cr-V(O)(TAML)](-) (1) and {[Cr-V(O)(TAML)]Sc3+}(2+) (1-Sc), were also characterized spectroscopically and/or structurally. In ET and oxygen atom transfer (OAT) reactions, while 1 and 1-Sc were sluggish oxidants, 2-Sc was a highly reactive oxidant with an extremely small reorganization energy. For example, in ET oxidation reactions, nanosecond laser-induced transient absorption measurements were performed to examine the fast ET from electron donors (e.g., ferrocene derivatives) to 2-Sc, affording a small reorganization energy (lambda = 0.26 eV) of ET, which is even much smaller than the lambda values reported in the ET reduction of heme Compound I (Cpd I) models and non-heme metal-oxo complexes. Such a small reorganization energy is ascribed to the TAML ligand centered ET reduction of 2-Sc. The lambda value of 0.26 eV was also obtained in the electron self-exchange reaction between 2-Sc and 1-Sc. In OAT reactions, the rate constants of the sulfoxidation of thioanisole derivatives by 2-Sc at -40 degrees C were much greater than those reported in the oxidation of thioanisoles by heme Cpd I and non-heme metal-oxo complexes. The reactivity of 2-Sc in hydrogen atom transfer (HAT) reactions is also discussed briefly. To the best of our knowledge, this Cr(V)-oxo TAML cation radical complex binding Sc3+ ion, {[Cr-V(O)(TAML(center dot+))]-Sc3+}(3+), with an extremely small reorganization energy is one of the most powerful high-valent metal-oxo oxidants in ET and OAT reactions.
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