title: Multi-Electron Oxidation of Anthracene Derivatives by Nonheme Manganese(IV)-Oxo Complexes.
abstract: Six-electron oxidation of anthracene to anthraquinone by a nonheme MnIV-oxo complex, [(Bn-TPEN)MnIV(O)]2+, proceeds through a rate-determining electron transfer from anthracene to [(Bn-TPEN)MnIV(O)]2+, followed by subsequent fast oxidation reactions to give anthraquinone. The reduced MnIIcomplex ([(Bn-TPEN)MnII]2+) is oxidized by [(Bn-TPEN)MnIV(O)]2+rapidly to produce the μ-oxo dimer ([(Bn-TPEN)MnIII-O-MnIII(Bn-TPEN)]4+). The oxygen atoms of the anthraquinone product were found to derive from the manganese-oxo species by the18O-labelling experiments. In the presence of Sc3+ion, formation of an anthracene radical cation was directly detected in the electron transfer from anthracene to a Sc3+ion-bound MnIV(O) complex, [(Bn-TPEN)MnIV(O)-(Sc(OTf)3)2]2+, followed by subsequent further oxidation to yield anthraquinone. When anthracene was replaced by 9,10-dimethylanthracene, electron transfer from 9,10-dimethylanthracene to [(Bn-TPEN)MnIV(O)-(Sc(OTf)3)2]2+occurred rapidly to produce stable 9,10-dimethylanthracene radical cation. The driving force dependence of the rate constants of electron transfer from the anthracene derivatives to [(Bn-TPEN)MnIV(O)]2+and [(Bn-TPEN)MnIV(O)-(Sc(OTf)3)2]2+was well-evaluated in light of the Marcus theory of electron transfer.
authors.affiliation: Department of Chemistry and Nano Science, Ewha Womans University, Seoul, 03760, Korea.
authors.forename: Namita
authors.initials: N
authors.lastname: Sharma
authors.affiliation: Department of Chemistry and Nano Science, Ewha Womans University, Seoul, 03760, Korea.
authors.forename: Jieun
authors.initials: J
authors.lastname: Jung
authors.affiliation: Department of Chemistry and Nano Science, Ewha Womans University, Seoul, 03760, Korea.
authors.forename: Yong-Min
authors.initials: YM
authors.lastname: Lee
authors.affiliation: Department of Chemistry and Nano Science, Ewha Womans University, Seoul, 03760, Korea.
authors.forename: Mi Sook
authors.initials: MS
authors.lastname: Seo
authors.affiliation: Department of Chemistry and Nano Science, Ewha Womans University, Seoul, 03760, Korea.
authors.forename: Wonwoo
authors.initials: W
authors.lastname: Nam
authors.affiliation: Department of Chemistry and Nano Science, Ewha Womans University, Seoul, 03760, Korea.|Faculty of Science and Engineering, SENTAN, Japan Science and Technology Agency (JST), Meijo University, Nagoya, Aichi, 468-8502, Japan.
authors.forename: Shunichi
authors.identifier: http://orcid.org/0000-0002-3559-4107
authors.initials: S
authors.lastname: Fukuzumi
keywords: anthracene; bioinorganic chemistry; electron transfer; hydrogen-atom transfer; manganese