Electron-transfer mechanism in radical-scavenging reactions by a vitamin E model in a protic medium

Ikuo Nakanishi, Tomonori Kawashima, Kei Ohkubo, Hideko Kanazawa, Keiko Inami, Masataka Mochizuki, Kiyoshi Fukuhara, Haruhiro Okuda, Toshihiko Ozawa, Shinobu Itoh, Shunichi Fukuzumi, Nobuo Ikota

Research output: Contribution to journalArticle

82 Citations (Scopus)

Abstract

The scavenging reaction of 2,2-diphenyl-1-picrylhydrazyl radical (DPPH*) or galvinoxyl radical (GO*) by a vitamin E model, 2,2,5,7,8-pentamethylchroman-6-ol (1H), was significantly accelerated by the presence of Mg(ClO4)2 in de-aerated methanol (MeOH). Such an acceleration indicates that the radical-scavenging reaction of 1H in MeOH proceeds via an electron transfer from 1H to the radical, followed by a proton transfer, rather than the one-step hydrogen atom transfer which has been observed in acetonitrile (MeCN). A significant negative shift of the one-electron oxidation potential of 1H in MeOH (0.63 V vs. SCE), due to strong solvation as compared to that in MeCN (0.97 V vs. SCE), may result in change of the radical-scavenging mechanisms between protic and aprotic media.

Original languageEnglish
Pages (from-to)626-629
Number of pages4
JournalOrganic and Biomolecular Chemistry
Volume3
Issue number4
DOIs
Publication statusPublished - 2005 Feb 21

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tocopherol
Scavenging
scavenging
Vitamin E
electron transfer
Electrons
Methanol
Protons
Hydrogen
Proton transfer
Solvation
Atoms
Oxidation
acetonitrile
solvation
hydrogen atoms
methyl alcohol
oxidation
protons
shift

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)
  • Chemistry(all)

Cite this

Electron-transfer mechanism in radical-scavenging reactions by a vitamin E model in a protic medium. / Nakanishi, Ikuo; Kawashima, Tomonori; Ohkubo, Kei; Kanazawa, Hideko; Inami, Keiko; Mochizuki, Masataka; Fukuhara, Kiyoshi; Okuda, Haruhiro; Ozawa, Toshihiko; Itoh, Shinobu; Fukuzumi, Shunichi; Ikota, Nobuo.

In: Organic and Biomolecular Chemistry, Vol. 3, No. 4, 21.02.2005, p. 626-629.

Research output: Contribution to journalArticle

Nakanishi, I, Kawashima, T, Ohkubo, K, Kanazawa, H, Inami, K, Mochizuki, M, Fukuhara, K, Okuda, H, Ozawa, T, Itoh, S, Fukuzumi, S & Ikota, N 2005, 'Electron-transfer mechanism in radical-scavenging reactions by a vitamin E model in a protic medium', Organic and Biomolecular Chemistry, vol. 3, no. 4, pp. 626-629. https://doi.org/10.1039/b416572a
Nakanishi, Ikuo ; Kawashima, Tomonori ; Ohkubo, Kei ; Kanazawa, Hideko ; Inami, Keiko ; Mochizuki, Masataka ; Fukuhara, Kiyoshi ; Okuda, Haruhiro ; Ozawa, Toshihiko ; Itoh, Shinobu ; Fukuzumi, Shunichi ; Ikota, Nobuo. / Electron-transfer mechanism in radical-scavenging reactions by a vitamin E model in a protic medium. In: Organic and Biomolecular Chemistry. 2005 ; Vol. 3, No. 4. pp. 626-629.
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