Unified Mechanism of Oxygen Atom Transfer and Hydrogen Atom Transfer Reactions with a Triflic Acid-Bound Nonheme Manganese(IV)-Oxo Complex via Outer-Sphere Electron Transfer
- 주제(기타) Chemistry, Multidisciplinary
- 설명문(일반) [Lee, Yong-Min; Kim, Surin; Kim, Kyung-Ha; Nam, Wonwoo; Fukuzumi, Shunichi] Ewha Womans Univ, Dept Chem & Nano Sci, Seoul 03760, South Korea; [Ohkubo, Kei] Osaka Univ, Open & Transdisciplinary Res Initiat, Inst Adv Cocreat Studies, Suita, Osaka 5650871, Japan; [Nam, Wonwoo] Chinese Acad Sci, Lanzhou Inst Chem Phys, Suzhou Res Inst LICP, State Key Lab Oxo Synth & Select Oxidat, Lanzhou 730000, Peoples R China; [Fukuzumi, Shunichi] Meijo Univ, Japan Sci & Technol Agcy JST, SENTAN, Fac Sci & Engn, Nagoya, Aichi 4680073, Japan
- 등재 SCIE, SCOPUS
- 발행기관 AMER CHEMICAL SOC
- 발행년도 2019
- URI http://www.dcollection.net/handler/ewha/000000159686
- 본문언어 영어
- Published As http://dx.doi.org/10.1021/jacs.8b12935
- PubMed https://pubmed.ncbi.nlm.nih.gov/30646680
초록/요약
Outer-sphere electron transfer from styrene, thioanisole, and toluene derivatives to a triflic acid (HOTf)-bound nonheme Mn(IV)-oxo complex, [(N4Py)-mn Mn-IV(O)](2+)-(HOTf)(2) (N4Py = N,N-bis(2-pyridylmethyl)-N-bis(2-pyridyl)methylamine), has been shown to be the rate determining step of different types of redox reactions such as epoxidation, sulfoxidation, and hydroxylation of styrene, thioanisole, and toluene derivatives, respectively, by [(N4Py)-Mn-IV(O)](2+)-(HOTf)(2). The rate constants of HOTf-promoted epoxidation of all styrene derivatives with [(N4Py)-Mn-IV(O)](2+) and electron transfer from electron donors to [(N4Py)Mn-V(O)](2+) exhibit a remarkably unified correlation with the driving force of outer-sphere electron transfer in light of the Marcus theory of electron transfer. The same electron transfer driving force dependence is observed in the oxygen atom transfer from [(N4Py)Mn-IV(O)](2+)-(HOTf)(2) to thioanisole derivatives as well as in the hydrogen atom transfer from toluene derivatives to [(N4Py)Mn-IV(O)](2+)-(HOTf)2. Thus, mechanisms of oxygen atom transfer (epoxidation and sulfoxidation) reactions of styrene and thioanisole derivatives and hydrogen atom transfer (hydroxylation) reactions of toluene derivatives by [(N4Py)Mn-IV(O)](2+)-(HOTf)(2) have been unified for the first time as the same reaction pathway via outer-sphere electron transfer, followed by the fast bond-forming step, which exhibits the singly unified electron-transfer driving force dependence of the rate constants as outer-sphere electron-transfer reactions. In the case of the epoxidation of cis-stilbene by [(N4Py)Mn-IV(O)](2+)-(HOTf)(2), the isomerization of cis-stilbene radical cation to trans-stilbene radical cation occurs after outer-sphere electron transfer from cis-stilbene to [(N4Py)Mn-IV(O)](2+)-(HOTf)(2) to yield trans-stilbene oxide selectively, which is also taken as evidence for the occurrence of electron transfer in the acid-catalyzed epoxidation.
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