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Updated: Dec 27, 2025
09:45
A Protocol for Safe Lithiation Reactions Using Organolithium Reagents
Published on: November 12, 2016
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酸素,窒素,およびハロゲンルイス基に対するダイアリドニウムイオンのルイス酸性スケール
Robert J Mayer1, Armin R Ofial1, Herbert Mayr1
1Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstrasse 5-13, 81377 München, Germany.
Journal of the American Chemical Society
|March 4, 2020
まとめ
この研究は,イオドニウムイオンのルイス酸性と様々な塩基のルイス基本性を定量化し,線形自由エネルギー関係を明らかにした. 発見は,溶解を強調しています.
科学分野:
- 超分子化学
- 物理有機化学
- 熱力学について
背景:
- ディアリオドニウム塩 (Ar2I+X-) は,有機合成における多用途の反応剤である.
- ルイス塩基との相互作用を理解することは,反応性を予測するために不可欠です.
- 以前の研究では,ルイス酸塩相互作用が調査されましたが,ヨドニウムイオンの包括的なスケールは欠けていました.
研究 の 目的:
- 17種類のダイアリオドニウム塩と11種類のルイス塩基の結合の均衡定数を体系的に調べる.
- イオドニウムイオンのルイス酸性および様々な核愛体のルイス塩基性を特徴付ける線形自由エネルギー関係 (LFER) を確立する.
- ヨドニウムイオンを含むルイス誘導体の形成を制御する熱力学および運動的要因を解明する.
主な方法:
- 均衡定数 (KI) は,アセトニトリルで20°Cでタイトリング方法 (光度計,伝導計) と同熱タイトリングカロメトリー (ITC) を用いて決定した.
- 線形自由エネルギー関係 (lg KI = s I LAI + LBI) を適用して,ルイス酸度 (LAI) とルイス塩度 (LBI) を定量化した.
- 熱力学的貢献と反応メカニズムを分析するために,温度依存の均衡測定と運動学的研究 (ベンゾアート移転) を実施した.
主要な成果:
- 均衡定数は6桁の大きさで 堅牢なLFERの開発を可能にしました
- 17のヨドニウムイオンに対するルイス酸性パラメータ (LAI) と10のルイス塩基に対するルイス塩基性パラメータ (LBI) と感受性 (sI) を成功裏に決定した.
- 溶解効果に起因するギブス反応エネルギーへの有意なエントロピー貢献が観察された. ベンゾアートの移転運動は,SN1型メカニズムを通じた第一次元の速度法則に従った.
結論:
- 確立されたLFERは,ヨドニウムイオンとのルイス酸塩相互作用を理解するための定量的な枠組みを提供します.
- イオドニウムイオンに対するルイス基本性は,カルベニウムイオンに対するものとは異なり,異なる熱力学的制御因子を示している.
- 溶解効果は,アニュート形成の熱力学において重要な役割を果たし,アニオン移動の運動学は機械的に定義されている.
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