Proton-coupled electron transfer (PCET) reactions play important roles in solar energy conversion processes. Designing efficient artificial photosystems with PCET mechanisms is a promising solution for the growing demands of energy resources. Compared to ground states, inducing the PCET reactions directly from electronically excited states, named excited-state PCET (ES-PCET) reactions, is a more direct and efficient avenue to the formation of solar fuels. Here, based on benzimidazole phenolic derivatives, we have designed and studied some molecular structures that can undergo the electron-driven double-proton transfer (EDDPT) reactions within the ES-PCET framework. According to our DFT/TDDFT calculation results, the two protons transfer in a stepwise manner in the EDDPT process, and compared to the common way of electron-driven single-proton transfer (EDSPT) reactions, the proton transfer in the EDDPT process not only has a smaller energy barrier but also experiences a longer transferring distance, which has beneficial effects on producing solar fuels. The study of ES-PCET reactions under the mechanism of EDDPT may cast light on the regulation of proton transfer at defined distances and time scales, which is important in energy conversion processes.

中文翻译：

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电子驱动双质子转移的分子设计：激发态质子耦合电子转移的新方案。

质子耦合电子转移（PCET）反应在太阳能转化过程中起着重要作用。使用PCET机制设计高效的人造光系统是满足不断增长的能源需求的有前途的解决方案。与基态相比，直接由电子激发态诱导PCET反应的方法被称为激发态PCET（ES-PCET）反应，是形成太阳能的更直接有效的途径。在这里，基于苯并咪唑酚类衍生物，我们设计和研究了一些分子结构，这些结构可以在ES-PCET框架内进行电子驱动的双质子转移（EDDPT）反应。根据我们的DFT / TDDFT计算结果，两个质子在EDDPT过程中逐步转移，与电子驱动单质子转移（EDSPT）反应的常规方式相比，EDDPT过程中的质子转移不仅具有较小的能垒，而且传递距离更长，这对生产太阳能燃料具有有益的影响。对EDDPT机理下的ES-PCET反应的研究可能会为在规定的距离和时间范围内质子转移的调控提供启示，这在能量转换过程中很重要。