Octahedral Cs2AgBiBr6 Double Perovskite Microcrystals for C–C Coupling Reactions under Visible-Light Irradiation

In this report, we demonstrate the first application of lead-free double perovskite microcrystals (Cs2AgBiBr6 MCs) in sustainable C–C coupling reactions. The Cs2AgBiBr6 MCs catalyst exhibits ultrahigh activity and selectivity in the α-alkylation of aldehyde and 2-bromoacetophenone, achieving a reaction rate of 2687.5 mmolg–1h–1, a turnover number (TON) value of 22854.5, and a turnover frequency (TOF) value of 2856.8 h–1, which are the highest among the known reports. The scalability of this system is validated through a continuous-flow reactor design, achieving 86% yield of 5.29 g of the target product at a gram-scale reaction. These results establish Cs2AgBiBr6 MCs as a promising platform for solar-driven C–C bond formation in organic transformations, combining the optoelectronic advantages of perovskites with environmental compatibility.