頑丈で固定されたCp*Ir転送水素化触媒の活性化と無活性化:多要素のX線吸収スペクトロスコピーの研究
Grant J Sherborne, Michael R Chapman, A John Blacker
1‡School of Chemistry, University of Nottingham, Nottingham NG7 2RD, United Kingdom.
Journal of the American Chemical Society
|March 14, 2015
まとめ
この研究では,転送水素化のリサイクル可能なイリジウム触媒について詳細に説明しています. 顕微鏡分析は,触媒がどのように活性化され,最終的に無効化されるかを明らかにし,触媒設計の洞察を提供します.
科学分野:
- 有機金属化学 有機金属化学
- カタリシス カタリシス カタリシス
- 材料科学 材料科学とは
背景:
- イモビライズされた触媒は,分離とリサイクルで利点があります.
- イリジウム複合体は,均質な触媒で広く使用され,特に転送水素化に使用されます.
- 触媒の無効化経路を理解することは,触媒の長寿を改善するために不可欠です.
研究 の 目的:
- 移転水素化の過程で固定された[Cp*IrCl2]2前触媒の構造と電子の変化を調査する.
- 触媒の活性化と無活性化のメカニズムを解明する.
- 構造変化と触媒性能との関係を確立する.
主な方法:
- X線吸収スペクトロスコーピー (XAS) は,Ir L3エッジ,Cl Kエッジ,KKエッジで実施されます.
- 触媒過程を監視するXAS実験を現地で行う.
- 催化剤の浸出を評価するための水銀中毒と熱い濾過実験.
主要な成果:
- 固定された [Cp*IrCl2]2 前触媒は,高い強度と再利用性 (30倍まで) を示した.
- 顕微鏡の証拠は,アクティベーションステップとして,クロリドリガンドの1つとアルコキシドの交換を特定しました.
- 不活性化は,第2の塩化物リガンドの交換によって起因し,アルコキシド-イリド酸カリウム種を形成した.
結論:
- 活性前触媒は,クロリドリガンドをアルコキシドに置き換えることで形成されます.
- 触媒の無効化は,第2塩化物リガンドの置換によって発生します.
- これらの発見は,頑丈でリサイクル可能な同質的および異質的イリジウム触媒の設計に関連しています.
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