Lacunary Evolution of Molybdenum Blue Clusters for Efficient and Sustainable Photocatalytic Chemodivergent C─C Coupling Reactions.

High-nuclearity molybdenum blue (MB) clusters with regular lacunary variation are of great importance for polyoxometalate structure evolution and photocatalytic application study, but their synthesis still remains a huge challenge. Herein, we successfully synthesized a series of high-nuclearity MB clusters, S2Mo62, SMo53W7, Mo50W8, and Mo44W8, which exhibit regular lacunary variation. More importantly, such structural variation endows these MB clusters with distinct Lewis acidity and redox properties. Consequently, when employed as heterogeneous photocatalysts for the chemodivergent C─C coupling reactions between 1,3-diketones and alkenes, the hexa-lacunary Mo50W8 and Mo44W8 with more Lewis acid sites can achieve a 93% 1,5-diketone yield within 12 h, while parent S2Mo62 with superior oxygen activation can achieve a 99% 1,4-diketone yield within 3 h. Furthermore, Mo50W8 enables gram-scale and sunlight driven synthesis of diverse 1,5-diketone, and maintains long-term cycling stability over 370 h (16 cycles). This work represents the first report of high-nuclearity MB clusters with regular lacunary variation, and extends their application to sunlight driven photocatalytic C─C coupling reaction, highlighting the innovative research of MB clusters.