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Isolating Free Carbenes, their Mixed Dimers and Organic Radicals
Published on: April 19, 2019
溶剂对碳化合物系统间交叉率的影响
Jin Wang1, Jacek Kubicki, Huolei Peng
1Department of Chemistry, The Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43210, USA.
Journal of the American Chemical Society
|April 25, 2008
概括
协调溶剂会影响碳素系统间交叉 (ISC) 速率. 特定的溶剂相互作用,而不仅仅是极性,通过稳定单片碳素来影响ISC,似乎违反了无辐射过渡的黄金规则.
科学领域:
- 物理化学 物理化学
- 摄影化学的使用.
- 化学动力学 化学动力学
背景情况:
- 系统间交叉 (ISC) 是一个关键的光物理过程,涉及分子的自旋状态变化.
- 碳是具有多种电子配置的反应性中间体,影响它们的光物理行为.
- 溶剂对反应速率和分子性质的影响是化学动态的基础.
研究的目的:
- 调查协调溶剂对单一到三重碳素系统间交叉 (ISC) 率的影响.
- 阐明溶剂影响ISC的机制,特别是对于二甲 (DPC) 和二三甲 (BpCCF 3) 的溶剂.
- 为了使观察到的溶剂效应与已建立的无辐射过渡理论相协调.
主要方法:
- 使用超快速时间分辨率光谱学来监测碳基动态.
- 通过在各种协调溶剂中使用二甲 (DPC) 和二三甲 (BpCCF 3) 进行了研究.
- 考虑了溶剂的特性,包括极性和特定的协调能力.
主要成果:
- 溶剂协调能力,而不是散装极性,显著影响DPC和BpCCF的ISC率3.
- 化溶剂显著减缓了BpCCF 3的ISC速率,这表明了特定的相互作用.
- 由于特定的溶解效应,观察到的ISC速率变化似乎与"黄金规则"相矛盾.
结论:
- 一个拟议的机制涉及单基碳与溶剂素原子的协调,形成一个伪化物复合体.
- 单基和三基碳的特定溶解产生了影响ISC率的弗兰克-康登式因素.
- 溶剂诱导的单片碳稳定导致更慢的ISC,挑战了简单的能量差距预测.
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