Electron Transfer Rate Maxima at Large Donor-Acceptor Distances
Electron Transfer Rate Maxima at Large Donor-Acceptor Distances
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DOI：
10.1021/jacs.5b11953
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发表时间：
2016-02-03
影响因子：
15
通讯作者：
Wenger, Oliver S.
中科院分区：
文献类型：
--
作者：
Kuss-Petermann, Martin;Wenger, Oliver S.
由于其低质量，电子可以在长距离(>；15埃)上快速转移，但通常反应速率随着施主-受主距离的增加而降低。本文报道了在给体-受体间距为30.6埃时的电子转移速率极大值，观察到了三个具有对二甲苯桥的刚性棒状给体-光敏剂-受体三元化合物中的一个蒽醌自由基阴离子与a，三芳胺自由基阳离子之间的热电子转移。我们的实验观察可以解释为电子给体-受体耦合的弱距离依赖性，以及(外球)重组能随着距离的增加而强烈增加，正如30多年前电子转移理论所预测的那样。观察到的效应对光到化学能的转换有重要的影响。
Because of their low mass, electrons can transfer rapidly over long (>15 angstrom) distances, but usually reaction rates decrease with increasing donor-acceptor distance. We report here on electron transfer rate maxima at donor-acceptor separations of 30.6 angstrom, observed for thermal electron transfer between an anthraquinone radical anion and a, triarylamine radical cation in three homologous series of rigid-rod-like donor-photosensitizer-acceptor triads with p-xylene bridges. Our experimental observations can be explained by a weak distance dependence of electronic donor-acceptor coupling combined with a strong increase of the (outer-sphere) reorganization energy with increasing distance, as predicted by electron transfer theory more than 30 years ago. The observed effect has important consequences for light-to-chemical energy conversion.