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A Highly Reactive Chromium(V)-Oxo TAML Cation Radical Complex in Electron Transfer and Oxygen Atom Transfer Reactions
- Title
- A Highly Reactive Chromium(V)-Oxo TAML Cation Radical Complex in Electron Transfer and Oxygen Atom Transfer Reactions
- Authors
- Hong, Young Hyun; Jang, Yuri; Ezhov, Roman; Seo, Mi Sook; Lee, Yong-Min; Pandey, Bhawana; Hong, Seungwoo; Pushkar, Yulia; Fukuzumi, Shunichi; Nam, Wonwoo
- Ewha Authors
- 남원우; Shunichi Fukuzumi; 서미숙
- SCOPUS Author ID
- 남원우; Shunichi Fukuzumi; 서미숙
- Issue Date
- 2021
- Journal Title
- ACS CATALYSIS
- ISSN
- 2155-5435
- Citation
- ACS CATALYSIS vol. 11, no. 5, pp. 2889 - 2901
- Keywords
- electron transfer; oxygen atom transfer; chromium(V)-oxo complex; redox-inactive metal ion; reorganization energy
- Publisher
- AMER CHEMICAL SOC
- Indexed
- SCIE; SCOPUS
- Document Type
- Article
- Abstract
- 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.
- DOI
- 10.1021/acscatal.1c00079
- Appears in Collections:
- 자연과학대학 > 화학·나노과학전공 > Journal papers
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