| 研究課題/領域番号 |
12J02902
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| 研究種目 |
特別研究員奨励費
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| 配分区分 | 補助金 |
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| 応募区分 | 国内 |
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| 研究分野 |
無機化学
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| 研究機関 | 大阪大学 |
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研究代表者 |
朴 ジュン (2012, 2014) 大阪大学, 大学院工学研究科, 特別研究員(PD)
朴 ジユン (2013) 大阪大学, 大学院工学研究科, 特別研究員(DC1)
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| 研究期間 (年度) |
2012 – 2014
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| 研究課題ステータス |
完了 (2014年度)
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| 配分額 *注記 |
3,300千円 (直接経費: 3,000千円、間接経費: 300千円)
2014年度: 1,300千円 (直接経費: 1,000千円、間接経費: 300千円)
2013年度: 1,000千円 (直接経費: 1,000千円)
2012年度: 1,000千円 (直接経費: 1,000千円)
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| キーワード | Electron Transfer / Lewis Acid / Epoxidation / Unification / C-H Bond Cleavage / Sulfoxidation / C-H結合開裂 / 電子移動 / 酸効果 |
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| 研究実績の概要 |
We report efficient epoxidation of styrene derivatives by a nonheme iron(IV)-oxo complex, [(N4Py)Fe^<IV>(O)]^<2+>(N4Py = N, N-bis(2-pyridylmethyl)-N- bis(2-pyridyl)methylamine) with trilflic acid (HOTf). No oxidation of styrene derivatives by [(N4Py)Fe^<IV>(O)]^<2+>(N4Py = N, N-bis(2-pyridylmethyl)-N-bis(2-pyridyl) methylamine) occurred in acetonitrile at 298 K, whereas efficient epoxidation of styrene derivatives was made possible by the presence of triflic acid (HOTf) via proton-coupled electron transfer (PCET) from styrene derivatives to the diprotonated species of [(N4Py)Fe^<IV>(O)]^<2+> with HOTf. Logarithms of the first-order rate constants of HOTf-promoted expoxidation of all styrene derivatives with [(N4Py)Fe^<IV>(O)]^<2+> and PCET from electron donors in the precursor complexes exhibit a remarkably unified correlation with the driving force of PCET in light of the Marcus theory of electron transfer when the differences in the formation constants of precursor complexes are taken into account. The same PCET driving force dependence is obtained for the first-order rate constants of HOTf-promoted oxygen atom transfer from thioanisols to [(N4Py)Fe^<IV>(O)]^<2+> and HOTf-promoted hydrogen atom transfer from toluene derivatives to [(N4Py)Fe^<IV>(O)]^<2+> in the precursor complexes. Thus, HOTf-promoted epoxidation of styrene derivatives by [(N4Py)Fe^<IV>(O)]^<2+> proceeds via the rate-determining electron transfer from styrene derivatives to the diprotonated species of [(N4Py)Fe^<IV>(O)]^<2+> as the case of HOTf-promoted oxygen atom transfer from thioanisols to [(N4Py)Fe^<IV>(O)]^<2+> and HOTf-promoted hydrogen atom transfer from toluene derivatives to [(N4Py)Fe^<IV>(O)]^<2+>.
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| 現在までの達成度 (区分) |
現在までの達成度 (区分)
1: 当初の計画以上に進展している
理由
All of oxidation reaction which occur by electron transfer from organic substrates to nonheme iron(IV)-oxo in the presence of Lewis acid can be unified in Marcus theory. With Lewis and Bronsted acid, such as metal ion and HOTf, effect on oxidation reaction by non-heme iron(IV)-oxo well studied in our system.
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| 今後の研究の推進方策 |
Lewis acids, such as redox inactive metal ion and proton, can promote oxidation reaction of organic substrate by nonheme iron(IV)-oxo complex via electron transfer. Huge enhancement came from precursor complex formation of metal ion-bounded or protomated nonheme iron(IV)-oxo and substrate. By using this super reactive species, the other oxidation reaction can be done which never has been studied by nonheme high-valent metal-oxo complex, not only with iron but also the other metals, Co, Cu, Cr and so on.
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