GATED ELECTRON-TRANSFER - WHEN ARE OBSERVED RATES CONTROLLED BY CONFORMATIONAL INTERCONVERSION
GATED ELECTRON-TRANSFER - WHEN ARE OBSERVED RATES CONTROLLED BY CONFORMATIONAL INTERCONVERSION
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DOI：
10.1021/ja00255a003
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发表时间：
1987-10-14
影响因子：
15
通讯作者：
RATNER, MA
中科院分区：
文献类型：
--
作者：
HOFFMAN, BM;RATNER, MA
我们探讨了当远程分子内电子转移（ET）发生在一个系统中，该系统表现出几种稳定的构象状态，这些构象状态可以以与电子转移竞争的速率相互转换时所产生的后果。第一部分回顾了适合传统分子内ET的动力学方案，其中反应物和生成物各自表现出单一的稳定构象。第二节讨论构象动力学的作用，然后继续发展适用于两态系统的动力学方案，其中电子转移在能量和动力学上耦合于两个稳定构象之间的转换。第三节给出了相应的动力学方程的解，并分析了它们最有趣的极限形式。我们发现构象的变化可以完全改变这些系统中电子转移过程的速率和机制，因此忽略这些现象的动力学测量解释可能会出现严重错误。这些结果被应用于解开电子转移和构象对当前感兴趣的系统影响的任务。
We explore the consequences that arise when long-range intramolecular electron transfer (ET) occurs in a system that exhibits several stable conformational states that can interconvert at rates competitive with electron transfer. Section I recalls the kinetic scheme appropriate for conventional intramolecular ET where reactant and product each exhibit a single stable conformation. Section II discusses the role of conformational dynamics and then proceeds to develop the kinetic scheme that applies to a two-state system in which electron transfer is energetically and kinetically coupled to the conversion between two stable conformations. Section III presents the solution of the corresponding kinetic equations and analyzes their most interesting limiting forms. We find that changes in conformation can entirely alter both the rate and the mechanism of electeron-transfer processes in these systems, and thus interpretations of kinetic measurements that ignore such phenomena can be dramatically in error. These results are applied to the task of disentangling electron-transfer and conformational influences on systems of current interest.