サイクロアルカンとサイクロアルケンのC-H結合解離エネルギー
Zhixin Tian1, Alireza Fattahi, Lev Lis
1Department of Chemistry, University of Minnesota, Minneapolis, MN 55455, USA.
Journal of the American Chemical Society
|December 21, 2006
まとめ
この研究では,サイクロブテンのC-H結合エネルギーを測定し,サイクロブタディエンの重要なデータを提供しました.
科学分野:
- 物理化学 物理化学
- 熱化学は熱化学である.
- コンピューティング・ケミストリー
背景:
- サイクロブテンのC-H結合解離エネルギー (C-H bond dissociation energies, BDE) は,その反応性を理解する上で極めて重要です.
- サイクロブタジエンの形成熱を決定するために,サイクロブタジエンの正確な熱化学データが必要です.
研究 の 目的:
- サイクロブテンのガス相C−H結合解離エネルギーを実験的に決定する.
- サイクロブタディエンの形成熱に関する実験データを提供するため.
- サイクロアルケンおよびサイクロアルケンのBDEの計算方法の精度を評価する.
主な方法:
- 陽子の親和性と電子結合エネルギーの測定を用いたガス相熱力学サイクル.
- 1および3サイクロブテニルアニオンの合成と特徴付け.
- サイクロアルカン,サイクロアルケン,および基準化合物の高レベルの初期計算 (G3およびW1).
主要な成果:
- サイクロブテンのアリルBDEは91.2 ± 2.3 kcalmol−1で,ビニルBDEは112.5 ± 2.5 kcalmol−1.1で測定されました.
- シス-2-ブーテンと比較すると,周期性アルカンおよびアルケンの一般的に引用される結合エネルギーにおける不一致が明らかになった.
- 計算によると,サイクロプロパン,サイクロブタン,サイクロヘキサンに関する文献のBDEは,mol−1.1.4 kcalで過小評価されている可能性がある.
結論:
- サイクロブタジエンの実験的なBDEは,サイクロブタジエンの形成熱の決定のための基礎を提供します.
- 小型の循環性炭化水素の一般的に受け入れられている結合エネルギーには,改定が必要である.
- 高レベルのコンピューティング方法は,正確な熱化学予測の可能性を示していますが,検証が必要です.
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