イミドとイミニルの窒素中枢レドックスによるC-H結合アミネーション効率の直接比較
Matthew J T Wilding1, Diana A Iovan1, Alexandra T Wrobel1
1Department of Chemistry and Chemical Biology, Harvard University , 12 Oxford Street, Cambridge, Massachusetts 02138, United States.
Journal of the American Chemical Society
|September 23, 2017
まとめ
鉄イミドとイミニル複合体は合成され,特徴づけられました. イミドからイミニル種への酸化は,アルキルイミニルがアリルイミニルよりも反応性があるため,トルーエンの活性化バリアを下げます.
科学分野:
- 有機金属化学
- 協調化学
- スペクトロスコーピー
背景:
- イミドおよびイミニルリガンドは,過渡金属化学において重要であり,反応性および電子特性に影響を与える.
- イミド/イミニル種の相互変換と反応性を理解することは,新しい触媒プロセスを開発する上で鍵となる.
研究 の 目的:
- 新しい鉄イミドとイミニル複合体を合成し,特徴づけること.
- 鉄イミドとイミニル種の電子と構造の違いを調査する.
- イミドからイミニルへの酸化が反応性,特にC-H活性化反応に及ぼす動的影響を研究する.
主な方法:
- 鉄イミドとイミニル複合体の合成は,特定の前駆体と反応剤を用いて行われます.
- EPR,57Feモースバウアー光譜,磁気測定,単結晶X線微分,XAS,EXAFSを含む特徴化技術.
- 活性化パラメータ (Ea) を決定するために,トルーエンの反応の運動分析.
主要な成果:
- 高スピンの鉄イミドとイミニル複合体を成功裏に合成し,特徴づけました.
- 構造分析により,イミドスのFe-N結合はイミニルと比較して短かった.
- X線吸収スペクトロスコーピーは,すべてのイミド/イミニル複合体の共通の鉄酸化状態を確認し,イミニルのユニークなNKエッジ特徴を特定した.
- イミドからイミニルへの酸化は,トルーエンの反応の活性化エネルギーを大幅に減少させることが示された.
結論:
- 鉄イミドとイミニル種間の相互変換は,それらの電子構造と反応性に影響します.
- イミニルのFe-N結合の相互作用は,イミドスと比較してC-H結合の活性化を促進する.
- アルキルイミニル複合体は,ラジカルの移位が減少したため,アリルイミニル複合体よりも低い活性化バリアを示す.
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