Nanoclusters as Deep‐Red Light‐Absorbing Photocatalysts for Laser‐ or LED‐Driven Povarov Cyclization

Abstract Photocatalysis is primarily initiated with ultraviolet/blue light, which has several drawbacks, namely, deficiencies in reaction efficiency, and scalability. Designing catalysts that can absorb low‐energy light offers a promising solution aiming at these drawbacks. In this study, we showed atomically precise gold nanoclusters serve as deep‐red‐absorbing photocatalysts towards Povarov‐type reactions driven by laser or LED irradiation, giving rise to complex tricyclic N‐heterocyclic compounds derived from bioactive molecules. Mechanistic studies revealed that the Au 15 cluster demonstrates two‐photon absorption when excited by a 700 nm laser, while maintaining a single‐photon excitation process under red LED irradiation. Furthermore, the versatility and broad applicability of the Au 15 photocatalyst were underscored through batch‐scalable photoreactions and various other deep‐red light‐induced reactions. Overall, the combination of nonlinear optics and photocatalysis of metal nanoclusters provides a new avenue for deep‐red photocatalysis with continuous and scalable capabilities.