レドックス・ポテンシャルと,水溶液中の非ヘム化合物Fe ((IV) = O複合体のC−H結合裂解特性
Dong Wang1, Mo Zhang, Philippe Bühlmann
1Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, USA.
Journal of the American Chemical Society
|May 19, 2010
まとめ
この研究は,陽子が高価鉄-オクソ複合体の酸化還元特性に大きな影響を及ぼし,この類の化合物において初めて可逆電気化学を可能にすることを明らかにしています. この発見は,C−H結合の酸化におけるこれらの鉄・オクソ種のユニークな反応性を強調しています.
科学分野:
- バイオ・オーガニック化学 バイオ・オーガニック化学
- 有機金属化学 有機金属化学
- 電気化学 電気化学について
背景:
- 高価鉄オキソ介質は,非ヘム酵素触媒における重要な酸化物質である.
- [Fe (IV) (O) (N4Py) ] (Fe (IV) (O) (N4Py) ] (N4Py) [Fe (IV) (O) ]) ] (N4Py) ] (N4Py) [Fe (IV) (O) ]) [Fe (IV) (O) ] (N4Py) ] (N4Py) [Fe (IV) (O) ]) [Fe (IV) (O) ] (N4Py) ] (N4Py) [Fe (IV) (O) ]) [Fe (IV) (O) ] (N4Py) [Fe (IV) (O)) ] (N4Py) [Fe (IV) (O)) ] (N4Py) [Fe (IV) (O)) ] (N4Py) [Fe (IV) (O) ] (N4Py) ] (N4Py) ] (N4Py) ] (N2+) のような合成のFe (IV) =O複合体は,C-H結合の裂解のための特性と反応性の安定性を提供しています.
- これらの複合体の酸化還元特性,特に陽子の影響は,まだ十分に研究されていない.
研究 の 目的:
- 合成鉄-オクソ複合体[Fe(IV) (((O) ((N4Py)) ((2+)) の酸化還元特性に対する陽子の影響を調査する.
- この複合体の電気化学的振る舞いを,非水溶液と水溶液の両方で探求する.
- C−H結合の酸化反応性に対するこれらのリドックス性質の影響を理解するために.
主な方法:
- サイクルボルトメトリーを含む電気化学研究は,様々な溶媒 (アセトニトリルと水) で実施されました.
- C-H結合の酸化反応は水溶液で研究されました.
- 熱力学的安定性と反応性は,構造的特徴と運動的測定を介して評価されました.
主要な成果:
- リバーシブルなFe(IV/III) 電化学は水溶液 (E(1/2) = +0.41 V vs SCEでpH4で観察され,電子と陽子の移転を伴う Fe(III) -OH種を形成しました.
- これは,非ヘムオキシ鉄 (IV) 複合体に対する可逆電気化学の最初の例を表しています.
- C-H結合の酸化率は,C-H結合の強度に依存するが,溶媒とは無関係であり,N4Pyリガンドが運動的優位性を与えることが判明した.
結論:
- プロトネーションは, [Fe ((IV)) ((O)) ((N4Py)) ] ((2+)) 複合体の酸化還元電位を可逆的に調節し,安定した電気化学観測を可能にします.
- 複合体から派生したFe(III) -OH種の計算されたD(O-H) 値は78(2) kcal mol(-1) である.
- N4Pyリガンド環境は,他の酸化物質と比較して,鉄-オクソ複合体のC-H結合割れ効率を高めます.
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