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Isolating Free Carbenes, their Mixed Dimers and Organic Radicals
Published on: April 19, 2019
1,3-二极体的二极根性质与它们对乙烯或乙的反应性之间存在明显的相关性
Benoit Braida1, Christof Walter, Bernd Engels
1CNRS UMR 7616, Laboratoire de Chimie Théorique, UPMC Université Paris 06, Case Courrier 137, 4 Place Jussieu, 75252 Paris, France. braida@lct.jussieu.fr
Journal of the American Chemical Society
|May 21, 2010
概括
1,3-二极体的二极根性质对于1,3-二极体循环加法反应至关重要. 一种拟议的机制涉及二极极扭曲到反应性二极极态,使无障碍的循环添加成为可能.
科学领域:
- 计算化学计算化学
- 有机化学 有机化学
- 量子化学 是一个量子化学.
背景情况:
- 1,3-双极循环添加是有机合成中的一个基本反应.
- 了解1,3-二极管的电子结构是控制反应性的关键.
- 以前的研究表明,这些反应中激进性质的重要性.
研究的目的:
- 量化评估各种1,3-二极管的二极根性质.
- 调查二根性质和循环加法障碍之间的关系.
- 为1,3-双极循环加法提出一个机制模型.
主要方法:
- 使用呼吸轨道价值键 (BOVB) 方法进行ab initio计算.
- 分析 1,3-双极电子结构作为价值键结构的线性组合.
- 电子特性与反应障碍之间的相关性分析.
主要成果:
- 对于9种1,3-二极体 (diazonium betaines,nitrilium betaines,azomethine betaines) 的二极性特征进行了定量估计.
- 在乙烯和乙烯的二极根性和循环添加障碍之间发现了强烈的线性相关性.
- 在扭曲到过渡状态时,1,3-二极点的二极点特征显著增加.
结论:
- 1,3-二极点的二极根性质是有利于1,3-二极点循环加法的一个关键因素.
- 一种拟议的机制涉及初始二极极扭曲到反应性二极极态,随后是没有障碍的循环加法.
- 这个模型与扭曲/相互作用能量模型保持一致,并解释了不同双极生物的相似障碍.
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