芳香二硫化基离子的形成和裂变
Sabrina Antonello1, Kim Daasbjerg, Henrik Jensen
1Dipartimento di Chimica Fisica, Università di Padova, via Loredan 2, 35131 Padua, Italy.
Journal of the American Chemical Society
|December 3, 2003
概括
电子转移到二二硫化物包括S-S键裂变. 替代效应影响重组能量和裂变率,在整个系列中具有一致的机制.
科学领域:
- 电化学 电化学 电化学
- 物理化学 物理化学
- 有机化学 有机化学
背景情况:
- 电子转移 (ET) 反应在化学和生物学中具有根本性的作用.
- 迪亚利二硫化物是具有可切割的S-S键的重要功能组.
- 了解替代剂对ET的影响对于预测反应性至关重要.
研究的目的:
- 为了研究电子转移机制对置换的二二硫化物.
- 为了将实验发现与理论分子轨道计算相关联.
- 量化描述异质和同质电子转移速率常数之间的关系.
主要方法:
- 在N,N-二甲基形式胺中使用电压测量和卷积分析进行实验电化学还原.
- 使用电生成基离子的均质电子转移研究.
- Ab initio分子轨道 (MO) 计算以确定电子结构和能量.
主要成果:
- 二硫化的减少是分离性的,涉及逐步的S-S键裂变.
- 这两种实验方法均为减少潜力和内在障碍提供了一致的估计.
- 对于电子捐赠群体,内部重组能量很大,随着电子吸收群体而减少.
- 随着哈梅特西格玛值的增加,S-S债券的分拆率下降.
结论:
- 确定了异质和同质ET速率常数之间的定量相关性.
- 尽管存在替代品变化,但SS债券分离机制在整个系列中基本一致.
- 内部重组能量和单独占用的分子轨道 (SOMO) 的移位是控制ET过程的关键因素.
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