TpPtMe ((H) ((2)):なぜメチル群のH/D乱雑化があるが,メタンの損失はないのか?
Mark A Iron1, H Christine Lo, Jan M L Martin
1Department of Organic Chemistry, Weizmann Institute of Science, 76100 Rehovot, Israel.
Journal of the American Chemical Society
|June 13, 2002
まとめ
ヒドリドトリス (((ピラゾリル) ボラートプラチナ複合体TpPtMe (((H) ((2) は,硬いリガンド構造によりメタンの損失に抵抗します. しかし,デュテラートメタノールによる可逆的なH/Dスクランブリングを容易に行う.
科学分野:
- 有機金属化学 有機金属化学
- コンピューティング・ケミストリー
- 反応メカニズム 解明 解明
背景:
- ヒドリドおよびメチルリガンドとのプラチナ複合体の反応性は,触媒作用において極めて重要です.
- 複合的な安定性と反応経路に対するリガンド効果を理解することは鍵となる.
- TpPtMe ((H) ((2) は,メタンの損失に対する安定性のユニークなケースを示しています.
研究 の 目的:
- TpPtMe (((H) (((2) の反応性を,特にメタンの損失に対する耐性を調査する.
- デュテラート溶媒で観察されたH/Dスクランブリングのメカニズムを解明する.
- 観察された反応性における硬質のTpリガンドの役割を決定する.
主な方法:
- 反応を研究するために,密度関数理論 (DFT) の計算が採用されました.
- 計算はmPW1k/LANL2DZ+P//mPW1k/LANL2DZの理論レベルで行われました.
- 比較分析には,モデルシステムである[(NH(3)) (((3) PtMe(H) ((2)) ](+) が使用されました.
主要な成果:
- Tpリガンドの硬さは,メタンの除去に必要なトランス幾何学を阻害し,エネルギー的に不利になります.
- メチルおよびヒドリドリガンドの可逆的なH/Dスクランブルは,エタ (2-CH) -CH (4) の中間体を通して容易に発生します.
- メタンの損失は観察されず,Tpリガンドの安定作用が確認されました.
結論:
- Tpリガンドの硬さは,TpPtMeのメタン損失を抑制する主要な要因である.
- H/Dスクランブルは,明確な中間経路を通って発生する簡単なプロセスです.
- 同様のシステムの精密なエネルギー計算には,mPW1k/SDB-cc-pVDZなどの特定のDFTレベルが必要です.
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