P-アリルフォスフィランの熱分解に関する計算研究:この方法によってアリルフォスフィニデンが生成されたか?
Wai Han Lam1, Peter P Gaspar, David A Hrovat
1Departments of Chemistry, University of Washington, Box 351700, Seattle, Washington 98195-1700, USA.
Journal of the American Chemical Society
|July 7, 2005
まとめ
計算化学は,トリプルフェニルフォスフィニデン (PhP) が段階的な経路で生成されることを明らかにし,これはエンド熱性が低く,シングレットPhPへの協調的な断片化よりも低い活性化バリアを持っています.
科学分野:
- 計算化学はコンピュータ化学である.
- 量子化学は量子化学である
- オーガニック・ケミストリー オーガニック・ケミストリー
背景:
- P-フェニルフォスフィラン (1) は,熱分解を起こすことができる分子です.
- 分断経路と分断産物の理解は,合成学と機械学の研究において極めて重要です.
研究 の 目的:
- P-フェニルホスフィラン (1) がフェニルホスフィニデン (PhP) とエチレンに熱分解する過程を調査する.
- シングレットとトリプル PhP につながる断片化の経路のエネルギーとステレオ化学を比較する.
主な方法:
- CASSCF,CASPT2,CCSDT,および (U) B3LYPを含む高レベルの電子構造計算が採用されました.
- 計算モデリングは,反応経路,移行状態,エネルギー障壁を分析するために使用されました.
主要な成果:
- トリペットPhPへの段階的な断片化は,シングレットPhPへの協調的な断片化と比較して,より低温 (21 kcal mol(-1)) とより低いバリア (12 kcal mol(-1)) を有する.
- シングレットPhPへの協調的な断片化はステレオ特異的であり,トリプレートPhP形成はステレオ化学の完全な喪失を示している.
- ディメチル-P-メシチルフォスフィランの計算は,よりステレオ特異的な三重メスP形成を示唆し,実験データと一致しています.
結論:
- 段階的な経路は,エネルギー要求が低いため,トリプルPhPの生成に優遇されます.
- シングレットとトリプレットフォスフィニデンの形成の間で,立体化学的結果が著しく異なる.
- MesP形成の高い活性化エネルギーは,それはおそらく触媒または異なる反応条件を必要とすることを示唆しています.
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