1,3,5-トリデヒドロベンゼントリラジカルは,サイクロプロペニルラジカルのアナログですか?
Harvey A Lardin1, John J Nash, Paul G Wenthold
1Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-1393, USA.
Journal of the American Chemical Society
|October 17, 2002
まとめ
この研究では,負イオン熱化学サイクルを使用して1,3,5-トリデヒドロベンゼントリラジカルのための形成熱を決定しました. この調査結果は,ベンゼンに関する洞察力を提供します.
科学分野:
- 物理化学 物理化学
- 熱化学は熱化学である.
- 量子化学とは,量子化学である.
背景:
- 1,3,5-トリデヒドロベンゼントリラジカルは,非常に反応性の高い中間物質です.
- その熱化学的性質を理解することは,反応機構の研究にとって極めて重要です.
研究 の 目的:
- 1,3,5-トリデヒドロベンゼントリラジカル形成のガス相熱を実験的に決定する.
- m-ベンジンの5位における結合解離エネルギー (BDE) を計算する.
- 実験結果と理論的な計算を比較し,電子構造の類似性を探求する.
主な方法:
- 負イオン熱化学サイクルを利用した.
- 3,5-ジクロルベンゾ酸のガス相酸度を測定した.
- 3,5-ジクロロベンゾ酸塩のデカルボキシル化と3,5-ジクロロフェニドからの塩化物損失のエンタルピーを決定した.
- 5-クロロ-m-ベンジンの電子相性および塩化物損失値の測定.
主要な成果:
- 5-クロロ-m-ベンジンの形成熱は116.2 ± 3.7 kcal/molと決定されました.
- 1,3,5-トリデヒドロベンゼントリラジカルの形成熱は179.1 ± 4.6 kcal/molで測定されました.
- m-ベンジンの5位におけるBDEは109.2 ± 5.6 kcal/molと計算され,ベンゼンにおける最初のBDEよりも低い.
結論:
- 1,3,5-トリデヒドロベンゼントリラジカルは,m-ベンジン部分と弱く相互作用するフェニルラジカルとして見ることができる.
- 実験的なBDE値は,多参照構成の相互作用計算とよく一致しています.
- トライラジカルの電子構造は,サイクロプロペニル系と類似している.
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