[16]におけるダイナミックなプロセスannulene: Möbius bond-shifting 経路から構成の変化までの経路
Ryan P Pemberton1, Colleen M McShane, Claire Castro
1Department of Chemistry, University of San Francisco, 2130 Fulton Street, San Francisco, CA 94117-1080, USA.
Journal of the American Chemical Society
|December 21, 2006
まとめ
計算方法により, [16]アンヌレンの構成を変えるための低エネルギー経路が明らかになった. これらのダイナミックなプロセスは,Möbiusのトポロジーの移行状態を含み, annulenesの簡単な熱構成変化を説明します.
科学分野:
- * 理論化学について
- * コンピュータ化学
- * オーガニック・ケミストリー
背景:
- * [16]アヌレンは,ダイナミックなプロセスを持つS4対称性のある分子として知られています.
- * 構造の自動化と構成の変化を理解することは極めて重要です.
研究 の 目的:
- * [16]annuleneにおける重要な動的プロセスのメカニズムを調査する.
- * 構成自動化とパイボンドシフトのためのエネルギーバリアを計算する.
- *これらの変換におけるモビウストポロジーの役割を調査する.
主な方法:
- * 密度関数理論 (DFT) とアビニシオ方法が採用されました.
- *計算にはBH&HLYP/6-311+G**とB3LYP/6-311+G**の理論レベルが使用されました.
- * 高レベルのカップリングクラスター理論 [CCSD(T) /cc-pVDZ(est) ]が検証に使用されました.
主要な成果:
- * 構成自動化のための2つの段階的な経路が,8-10 kcal/molの計算されたエネルギーバリアで特定されました.
- * 移行状態はモビウス・トポロジーを示し,パイ・ボンドのシフトと構成の変化を容易にする.
- * 鍵移行状態 (TS1-2) のエネルギーは,CCSD (T) レベルで13.7 kcal/molと計算され,実験データを括弧にしました.
- *他のいくつかのモビウス結合シフト移行状態とコンフォーマーション最小値は,基底状態の22 kcal/mol以内で見つかりました.
結論:
- * [16]アヌレンの容易な熱構成の変化は,モビウス移行状態を含むトウィストカップルの結合シフトメカニズムを通じて発生します.
- * これらのメカニズムは,単一の二基変遷状態を経由する非循環型ポリエンのメカニズムと対照的です.
- *この研究は,モビウスのトポロジーは,[n]アヌレンのダイナミックな行動において重要な役割を果たすという仮説を支持する.
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