なぜIr (III) 媒介のアミド移転はRh (III) 媒介の反応よりもはるかに速いのか? 実験と計算を組み合わせた研究
Yoonsu Park1,2, Joon Heo1, Mu-Hyun Baik1,2
1Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST) , Daejeon 34141, Republic of Korea.
Journal of the American Chemical Society
|October 4, 2016
まとめ
この研究は,イリジウムとロジウム触媒によるC−N結合のC−Hアミデーションのメカニズムを明らかにしている. 新型アミダント剤は,イリジウムの詳細な機械的洞察を可能にしました.
科学分野:
- 有機金属化学
- カタリシス
- 反応機構の解明
背景:
- 触媒性C−Hアミデーションは,窒素を含む化合物の合成に不可欠である.
- イリジウム (Ir) とロジウム (Rh) を媒介するC−N結合の反応機構を理解することは,触媒の設計と最適化に不可欠である.
- 以前の研究では,重要なC−N結合段階に関する詳細な機械的洞察が欠けていました.
研究 の 目的:
- Ir (III) とRh (III) を媒介するC−N結合反応のメカニズムを調査する.
- 1,4,2-ダイオクサゾール部分を含む新型アミダ剤が,触媒性C-Hアミダーションにおける役割を明らかにする.
- C−N カップリングにおけるIrとRhのメカニズム的経路と反応性を比較する.
主な方法:
- 実験と計算を統合した研究
- C-N結合反応のステキオメトリックバージョンを設計するために新しいアミダント剤を使用した.
- 密度関数理論 (DFT) の計算と運動学的研究を使用した.
- 完全な分子軌道分析を行いました
主要な成果:
- M (III) コンプレックスとM (V) イミドの中間物質の酸化結合を伴うメカニズムが提案された.
- イリジウム (Ir) は,急速な酸化結合により,著しく高い反応性 (Rhより約1,100倍) を示した.
- Irの場合,初期複合体の活性化が速度を制限し,Rhの場合,Rh- imido形成が速度を制限する.
- 独特のダイオクサゾール分子の結合と,Ir (V) に対する相対的な効果は,反応性の違いを説明する.
結論:
- この研究は,触媒性C−HアミデーションにおけるIr−とRh−媒介のC−N結合に関する前例のないメカニズム的な詳細を提供します.
- 新しいアミダント剤は,メカニズム研究とステキオメトリック反応に有効です.
- Ir と Rh の間の有意な反応性差は,電子的および相対的効果に起因し,触媒の開発のための洞察を提供します.
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