ルイス塩基としてのコロナヌレンは,プロトネーションとリチウムカチオン結合の計算モデル化です
M V Frash1, A C Hopkinson, D K Bohme
1Department of Chemistry, Centre for Research in Mass Spectrometry, York University, Toronto, Ontario, Canada.
Journal of the American Chemical Society
|July 6, 2001
まとめ
コンピューティング・モデリングにより,コラヌルレンが発見された.
科学分野:
- コンピューティング・ケミストリー
- 超分子化学 超分子化学
- マテリアルサイエンス 材料科学
背景:
- コラヌレンは,カーブされたポリサイクル芳香炭化水素であり,先進的な材料の基本的な構成要素として機能します.
- 陽子と亜陽子との反応性を理解することは,新しい分子構造と機能的な材料の設計に不可欠です.
研究 の 目的:
- コランヌレンの分子上のプロトネーション部位とエネルギーを計算的に調査するために.
- コランヌレンのリチウムカチオンの好ましい結合場所とエネルギーを決定する.
- NMR化学シフトとNICSを用いたプロトネーション時のコラヌレンの芳香度変化を分析する.
主な方法:
- 密度関数理論 (DFT) の計算は,B3LYP関数を使って 6-311G(d,p) と 6-31G(d,p) のベースセットを使用しています.
- リチウムカチオン相互作用における陽子の親和性と結合エネルギーの分析.
- (7) Li NMR化学シフトと核独立化学シフト (NICS) を計算して,芳香性を探知する.
主要な成果:
- プロトネーションは,最も内側の炭素原子で優先的に発生し,安定したシグマ複合体を形成し,プロトンの親和度は203 kcal mol ((-1) である.
- リチウムカチオンは,凸面の6環に優位に結合し,面の動きが容易であるが,縁の周囲には高い障壁がある.
- ボウルからボウルへの逆転は中程度の活性化エネルギー (7-12 kcal mol ((-1)) を有し,計算されたLi ((+)) 結合エネルギーは44 kcal mol ((-1)) である.
結論:
- コランヌレンは,ハブ炭素が最も有利な場所である,明確なプロトネーションの好みを表しています.
- リチウムカチオン結合は,コラヌレンの曲線と環構造の影響を受け,宿主-ゲスト化学への影響があります.
- NMRシフトとNICSの計算分析は,電子構造とゲスト結合時の芳香度調節に関する洞察を提供します.
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