Bimolecular Photoinduced Electron Transfer Beyond the Diffusion Limit: The Rehm-Weller Experiment Revisited with Femtosecond Time Resolution
Bimolecular Photoinduced Electron Transfer Beyond the Diffusion Limit: The Rehm-Weller Experiment Revisited with Femtosecond Time Resolution
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DOI：
10.1021/ja4118279
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发表时间：
2014-02-05
影响因子：
15
通讯作者：
Vauthey, Eric
中科院分区：
文献类型：
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作者：
Rosspeintner, Arnulf;Angulo, Gonzalo;Vauthey, Eric
为了获得内在的，无扩散，双分子光诱导电子转移反应的速率常数，荧光猝灭实验已进行了14个供体/受体对，覆盖驱动力范围从0.6至2.4 eV，使用稳态和飞秒时间分辨发射，并应用扩散反应模型，占静态和瞬态阶段的猝灭的分析。内禀电子转移速率常数比在乙腈中的扩散速率常数大2个数量级。电子伏特以上，观察到的速率常数略有下降，指向一个弱得多的马库斯反转区域比其他类型的电子转移反应，如电荷复合。尽管如此，驱动力的依赖性可以合理化的马库斯理论。
To access the intrinsic, diffusion free, rate constant of bimolecular photoinduced electron transfer reactions, fluorescence quenching experiments have been performed with 14 donor/acceptor pairs, covering a driving-force range going from 0.6 to 2.4 eV, using steady-state and femtosecond time-resolved emission, and applying a diffusion-reaction model that accounts for the static and transient stages of the quenching for the analysis. The intrinsic electron transfer rate constants are up to 2 orders of magnitude larger than the diffusion rate constant in acetonitrile. Above eV, a slight decrease of the rate constant is observed, pointing to a much weaker Marcus inverted region than those reported for other types of electron transfer reactions, such as charge recombination. Despite this, the driving force dependence can be rationalized in terms of Marcus theory.