Photosynthesis of AuCu nanocluster for photocatalysis in oxidative functionalization of alkynes.

Ligand-protected metal nanoclusters provide an ideal platform for investigating photoredox catalysis. The central challenge is balancing their stability and catalytic activity. Here we show a photochemical reduction-oxidation cascade method for synthesizing an AuCu nanocluster, which features a robust structure and active surface. Photoredox catalytic activity of AuCu is developed for the functionalization of alkynes under oxidative conditions. Mechanism studies based on the precise structure reveal the catalytic process of the AuCu nanocluster. Oxidant-dependent selectivity of AuCu catalysis is developed for chemodivergent synthesis of mono- and di-functionalized products in high efficiency. The results will stimulate more research on metal nanocluster synthesis and catalysis.