Electron-donating sacrificial reagents are highly important for certain photo-redox reactions. However, the use of excessive amounts of sacrificial reagents, mostly amines, often leads to undesired side products and is especially troublesome for product purification. Herein, we take the light-induced electron transfer cascade process of natural photosystems as a role model and assemble organic photocatalysts into cooperative photocatalyst couples. The cooperative photocatalyst couples could undergo intermolecular electron transfer to facilitate the charge separation process and overcome the need for an extra electron donor. Time-resolved photoluminescence spectroscopy was conducted to precisely characterize the photo-excited dynamics within the cooperative photocatalyst couples. As a model photoredox reaction, the carbon–carbon formation reaction between heteroarenes and malonates, which usually requires electron-donating sacrificial reagents such as amines, was conducted to demonstrate the feasibility of the cooperative photocatalyst couples under visible light irradiation. A significant reaction conversion improvement from trace conversion for a single photocatalyst system to over 90% by cooperative photocatalyst couples was achieved.

中文翻译：

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协作有机光 催化剂通过电子转移级联实现无电子给体的光氧化还原催化†

给电子牺牲试剂对于某些光氧化还原反应非常重要。然而，使用过量的牺牲试剂，主要是胺，通常会导致不希望的副产物，并且对于产物纯化特别麻烦。在这里，我们以自然光系统的光诱导电子转移级联过程为榜样，并将有机光催化剂组装成协同的光催化剂对。协同光催化剂对可以进行分子间电子转移，以促进电荷分离过程并克服对额外电子供体的需求。进行时间分辨光致发光光谱法以精确表征协同光催化剂对内的光激发动力学。作为模型的光氧化还原反应，进行了杂芳烃和丙二酸酯之间的碳-碳形成反应，该反应通常需要提供电子的牺牲试剂，例如胺，以证明在可见光照射下配合光催化剂对的可行性。从单光催化剂体系的痕量转化到协作光催化剂对的90％以上，反应转化率有了显着提高。