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反氧活性离子配对激发状态经历动态电子转移

Ludovic Troian-Gautier¹, Evan E Beauvilliers¹, Wesley B Swords¹

¹Department of Chemistry, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599-3290, United States.

Journal of the American Chemical Society

|December 16, 2016

概括

与化物结合的复合离子增强了兴奋状态电子转移. 这种相互作用,特别是与化物,促进了在孤立的复合物中未见的氧化,由静电工作条件驱动.

科学领域:

摄影化学
协调化学
超分子化学

背景情况:

在光化学和催化过程中,复合物至关重要.
了解离子对相互作用对于调整反应性至关重要.
激发状态动态中的 counterions 的作用需要进一步的研究.

研究的目的:

研究复合体和化离子之间的离子对相互作用.
阐明离子配对对激发状态电子转移的影响.
量化静电工作条件对反应驱动力的贡献.

主要方法:

复合物的合成和表征[Ru(dtb) 2 ((dea) ]PF6]2.
探测离子配对和激发状态属性的光谱研究 (UV-Vis,辐射,1H NMR).
使用自然键轨道 (NBO) 计算来确定静电贡献的计算分析.

主要成果:

在复合体 (C1^2+) 和Cl-, Br-, I-之间形成稳定的离子对,平衡常数高 (10^4-10^6M^-1在CH3CN中).
离子配对激发状态表现出更长的寿命,增强的排放和增加的自由能量储存.
在1:1的化物:兴奋状态离子对中观察到扩散电子转移氧化,这种过程在没有离子配对的情况下是不存在的.
自然键序计算量化了工作期 (ΔGw) 作为增强的电子转移反应率的主要驱动因素.

结论:

离子配对显著调节复合物的光物理和光化学特性.
增强的电子转移反应性归因于离子对内的有利的静电相互作用 (工作期),而不仅仅是增加光氧化剂强度.
提出了一个模型,其中离子配对促进化物氧化,与非离子配对状态的捕获效应形成对比.

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