Interest in applying proton-coupled electron transfer (PCET) reagents in reductive electro- and photocatalysis requires strategies that mitigate the competing hydrogen evolution reaction. Photoexcitation of a PCET donor to a charge-separated state (CSS) can produce a powerful H-atom donor capable of being electrochemically recycled at a comparatively anodic potential corresponding to its ground state. However, the challenge is designing a mediator with a sufficiently long-lived excited state for bimolecular reactivity. Here, we describe a powerful ferrocene-derived photoelectrochemical PCET mediator exhibiting an unusually long-lived CSS (τ ∼ 0.9 μs). In addition to detailed photophysical studies, proof-of-concept stoichiometric and catalytic proton-coupled reductive transformations are presented, which illustrate the promise of this approach.

中文翻译：

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还原光电催化中持续电荷转移状态的分子间质子耦合电子转移反应

在还原电催化和光催化中应用质子耦合电子转移（PCET）试剂的兴趣需要减轻竞争性析氢反应的策略。 PCET 供体光激发至电荷分离态 (CSS) 可以产生强大的氢原子供体，能够在与其基态相对应的相对阳极电位下进行电化学回收。然而，挑战在于设计一种具有足够长寿命的激发态以实现双分子反应的介体。在这里，我们描述了一种强大的二茂铁衍生的光电化学 PCET 介体，其表现出异常长的 CSS 寿命（τ ∼ 0.9 μs）。除了详细的光物理研究之外，还提出了概念验证化学计量和催化质子耦合还原转化，这说明了这种方法的前景。