モリブデンアルキンメタテシスの分子およびシリカ系触媒:電子とダイナミクスが運動学,固体NMRおよび化学シフト分析によって示された活動への影響
Deven P Estes1, Christopher P Gordon1, Alexey Fedorov1
1Department of Chemistry and Applied Biosciences, ETH Zürich , Vladimir-Prelog-Weg 1-5, 8093 Zürich, Switzerland.
Journal of the American Chemical Society
|October 31, 2017
まとめ
モリブデンアルキリジンの触媒におけるフッ素置換は,アルキンの転化におけるそれらの電子特性および触媒活性を調節する. 支持された触媒は,電離性および動力の低下のために,分子類似体と比較して活動性が低下しています.
科学分野:
- 有機金属化学
- カタリシス
- 材料科学
背景:
- モリブデンアルキリジンの複合体は,触媒作用において極めて重要です.
- 構造と活動の関係を理解することは,触媒の設計の鍵です.
研究 の 目的:
- モリブデン基の分子とシリカ基のアルキリジン触媒の一連の合成と特徴づけ
- フッ素置換が触媒特性とアルキン転移活性に及ぼす影響を調査する.
- 触媒の性能を左右するメカニズム的な側面を明らかにする.
主な方法:
- モリブデンアルキリジン複合体の合成と特徴付け ([MesCMo{OC(CH3) 3-x(CF3) x}3)).
- 詳細な分子分析のための固体核磁気共振 (NMR) スペクトロスコーピー.
- アルキンメタテシスの触媒活性評価
- 理論的な洞察のための密度関数理論 (DFT) /ZORA計算.
主要な成果:
- アルキリジン炭素の脱シールド13C NMR化学的シフトと相関するリガンドのフッ素含有量増加.
- MoF0 < MoF3 < MoF6の順番で,MoF9では急激に減少した.
- MoF9の誘導体はゼロ級の運動性と安定したメタラサイクロブタディエンの中間物質を示した.
- シリカを支える触媒は,分子対比よりも活動性が低く,電化性が低く,ダイナミック性が低い.
結論:
- フッ素置換は,モリブデンアルキリジンの触媒の電子構造と反応性を効果的に調節する.
- 安定したメタラサイクロブタディエンの中間物質の形成は,高化MoF9触媒の活性を制限する.
- シリカ支柱は,電離性および動力を減らし,制御された触媒の活性性を抑制し,制御された触媒の活性化を可能にします.
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