Atomically Precise Rigid Copper Nanocluster as an Air-Stable Photocatalyst for Three-Component Coupling Reactions

Copper-based catalysts exhibit high versatility in organic synthesis. However, their practical utility is often constrained by the limited stability and sensitivity to reaction conditions. In this study, we report a μ₃-η¹-S-bridged nanocluster (NC), Cu₃(DPPM)₃S(BF₄) (Cu₃S, DPPM = Bis(diphenylphosphino)methane), that displays exceptional air stability and catalytic robustness due to its strong Cu-S coordination and rigid trigonal symmetry structure. Enabled by its structural stability and excellent photophysical properties, the Cu₃S NC functions as an efficient photocatalyst for the three-component coupling reaction of alkyl halides, amines, and alkenes under open-air, room-temperature conditions. The catalyst displays high turnover numbers, broad functional group tolerance, and excellent recyclability over multiple cycles. Our findings establish structurally well-defined low-nuclearity NCs as versatile and durable catalysts for multicomponent C-N/C-C bond-forming transformations and reveal structural rigidity as a key design principle for achieving catalytic stability.