Deuterium kinetic isotope effects as redox mechanistic criterions
- 주제(키워드) acid-promoted electron transfer , deuterium kinetic isotope effect , inverse kinetic isotope effect , proton-coupled electron transfer , tunneling effect
- 주제(기타) Chemistry, Multidisciplinary
- 설명문(일반) [Fukuzumi, Shunichi; Lee, Yong-Min; Nam, Wonwoo] Ewha Womans Univ, Dept Chem & Nano Sci, Seoul 03760, South Korea; [Fukuzumi, Shunichi] Meijo Univ, Fac Sci & Engn, Nagoya, Aichi, Japan; [Lee, Yong-Min] Ewha Womans Univ, Res Inst Basic Sci, Seoul, South Korea
- 등재 SCIE, SCOPUS
- 발행기관 WILEY-V C H VERLAG GMBH
- 발행년도 2021
- 총서유형 Journal
- URI http://www.dcollection.net/handler/ewha/000000191130
- 본문언어 영어
- Published As https://doi.org/10.1002/bkcs.12417
초록/요약
This account article focuses on deuterium kinetic isotope effects (KIEs) used as criterions to elucidate redox mechanisms including proton-, hydrogen- and hydride-transfer reactions. Hydrogen atom transfer (HAT) is composed of two elementary steps: electron transfer (ET) and proton transfer (PT), while hydride transfer is composed of three elementary steps: ET, PT, and ET. Large tunneling effects are often observed for proton-coupled electron-transfer (PCET) reactions of metal-oxygen complexes in which ET occurs to the metal center and PT occurs simultaneously to the ligand, exhibiting large KIEs. Whether HAT proceeds via sequential ET/PT, PT/ET, or concerted PCET (cPCET) depending on the redox properties of hydrogen donors and acceptors to exhibit different KIEs. Whether hydride transfer also proceeds via sequential ET/PT/ET, PT/ET/ET, or cPCET/ET depending on the redox properties of hydride donors and acceptors to exhibit different KIEs. Temperature dependence of KIEs for aldehyde deformylation reactions has enabled to distinguish two reaction pathways: one is a HAT and the other is a nucleophilic addition. The change of the mechanism from cPCET to sequential ET/PT is made possible by binding acids to the hydrogen and hydride acceptors when no KIE is observed. Inverse KIEs are also discussed for acid (or deuteron)-promoted ET reactions.
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