Cuprous Cluster-Based Coordination Sheets as Photocatalytic Regulators to Activate Oxygen, Benzoquinone, and Thianthrenium Salts

Cuprous clusters are well known for their important fluorescent properties and tunable redox behavior, but the coordinated protecting groups restrict their application in photocatalysis, in particular, the inner-sphere activation of substrates. By modifying fluorescent cuprous clusters with terminal iodides into two-dimensional coordination sheets, we report a photocatalytic regulator to synergistically combine electron transfer and energy transfer for the oxidative coupling of benzoquinone and terminal alkynes. Under visible light irradiation, the well-modified excited state of the cuprous clusters in the coordination sheets reduces benzoquinones to generate aoxy radicals through electron transfer and activates oxygen through energy transfer. The aoxy radicals interact with copper-coordinated phenylacetylene to form an active intermediate, which is further oxidized by the in situ formed active oxygen species and aryl ketones are obtained. The warranted potential of the excited coordination sheets enables the reductive activation of thianthrenium salts as radical precursors, facilitating radical capture and further C–N coupling via an inner-sphere activation mechanism. The new catalytic approach optimizes the redox properties and excited-state lifetime, shortens the electron transfer steps, and promotes the potential collision of a low concentration of active species in tandem catalytic cycles, thus paving a new way to develop ecologically benign, cost-effective, multipurpose, and flexible catalytic systems.亚铜团簇（cuprous clusters）以其优异的荧光特性（fluorescent properties）与可调的氧化还原行为（tunable redox behavior）而广为人知，但其配位保护基团（coordinated protecting groups）限制了其在光催化（photocatalysis）领域的应用，尤其是底物的内层活化（inner-sphere activation）过程。本研究通过将末端碘化物（terminal iodides）修饰的荧光亚铜团簇构建为二维配位片层（two-dimensional coordination sheets），报道了一种可协同结合电子转移（electron transfer）与能量转移（energy transfer）的光催化调节剂（photocatalytic regulator），用于苯醌（benzoquinone）与末端炔烃（terminal alkynes）的氧化偶联（oxidative coupling）反应。在可见光辐照（visible light irradiation）下，配位片层中亚铜团簇经修饰后的激发态（excited state）可通过电子转移还原苯醌以生成烷氧自由基（aoxy radicals），并通过能量转移活化氧气。该烷氧自由基与铜配位的苯乙炔（copper-coordinated phenylacetylene）相互作用形成活性中间体（active intermediate），该中间体可被原位生成的活性氧物种（active oxygen species）进一步氧化，最终得到芳基酮（aryl ketones）类化合物。该激发态配位片层所具备的可靠应用潜力，使其可将噻蒽鎓盐（thianthrenium salts）还原活化为自由基前驱体（radical precursors），并通过内层活化机制（inner-sphere activation mechanism）促进自由基捕获（radical capture）与后续的C-N偶联（C–N coupling）反应。这一新型催化策略优化了氧化还原特性（redox properties）与激发态寿命（excited-state lifetime），缩短了电子转移步骤（electron transfer steps），提升了串联催化循环（tandem catalytic cycles）中低浓度活性物种的有效碰撞概率，从而为开发生态友好（ecologically benign）、成本效益高（cost-effective）、多功能（multipurpose）且灵活可调的催化体系开辟了全新路径。