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Two Pathways in Scandium Ion-Coupled Electron Transfer of Superoxide Ion
https://repo.qst.go.jp/records/70380
https://repo.qst.go.jp/records/70380f4983664-d6be-4655-8a05-9ed94d42a70f
| Item type | 会議発表用資料 / Presentation(1) | |||||
|---|---|---|---|---|---|---|
| 公開日 | 2011-01-05 | |||||
| タイトル | ||||||
| タイトル | Two Pathways in Scandium Ion-Coupled Electron Transfer of Superoxide Ion | |||||
| 言語 | ||||||
| 言語 | eng | |||||
| 資源タイプ | ||||||
| 資源タイプ識別子 | http://purl.org/coar/resource_type/c_c94f | |||||
| 資源タイプ | conference object | |||||
| アクセス権 | ||||||
| アクセス権 | metadata only access | |||||
| アクセス権URI | http://purl.org/coar/access_right/c_14cb | |||||
| 著者 |
Kawashima, Tomonori
× Kawashima, Tomonori× Ohkubo, Kei× Nakanishi, Ikuo× Fukuzumi, Shunichi× 川島 知憲× 中西 郁夫 |
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| 抄録 | ||||||
| 内容記述タイプ | Abstract | |||||
| 内容記述 | Superoxide ion (O2•–) forms a stable 1:1 complex with scandium hexamethylphosphoric triamide complex [Sc(HMPA)33+], which can be detected by ESR spectroscopy in solution at ambient temperature. We report kinetics and mechanism of electron-transfer reactions from the O2•––Sc(HMPA)33+ complex to a series of electron acceptors: p-benzoquinone derivatives such as p-benzoquinone and coenzyme Q10. Electron transfer from the O2•––Sc(HMPA)33+ complex to a series of p-benzoquinone derivatives occurs, accompanied by binding of Sc(HMPA)33+ to the corresponding semiquinone radical anion complex to produce the semiquinone radical anion-Sc(HMPA)33+ complexes. The 1:1 and 1:2 complexes between semiquinone radical anions and Sc(HMPA)33+ depending on the type of semiquinone radical anions were detected by ESR measurements. This is defined as Sc(HMPA)33+-coupled electron transfer. There are two reaction pathways in the Sc(HMPA)33+-coupled electron transfer. One is a stepwise pathway in which the binding of Sc(HMPA)33+ to semiquinone radical anions occurs after the electron transfer, when the rate of electron transfer remains constant with the change in concentration of Sc(HMPA)33+. The other is a concerted pathway in which electron transfer and the binding of Sc(HMPA)33+ occurs in a concerted manner, when the rates of electron transfer exhibit first-order and second-order dependence on concentration of Sc(HMPA)33+ depending the number of Sc(HMPA)33+ (one and two) bound to semiquinone radical anions. The contribution of two pathways is changed depending on substituents on p-benzoquinone derivatives. The present study provides the first example to clarify the kinetics and mechanism of metal ion-coupled electron-transfer reactions of superoxide ion. | |||||
| 会議概要（会議名, 開催地, 会期, 主催者等） | ||||||
| 内容記述タイプ | Other | |||||
| 内容記述 | The 2010 International Chemical Congress of Pacific Basin Societies (PACIFICHEM 2010) | |||||
| 発表年月日 | ||||||
| 日付 | 2010-12-20 | |||||
| 日付タイプ | Issued | |||||
