Near-Infrared (1050 nm) Light-Driven Molecular Cobalt Photocatalysis

Photocatalysis has revolutionized synthetic chemistry; however, the reliance of exciting photocatalysts on high-energy photons limits the practical applications of this approach. Development of molecular photocatalysts that can be activated by near-infrared (NIR) light would fundamentally broaden the scope of photocatalysis. Here, we report a radical-featured cobalt complex that catalyzes the aerobic oxidation of benzylamines under 1050-nm irradiation—the longest wavelength ever recorded for a homogeneous molecular photocatalyst. This NIR light-driven photocatalysis was shown to remain efficient in large-volume reactions and turbid media, and to show wavelength-orthogonal tandem reactivity, highlighting its advantages over ultraviolet/visible light-driven photocatalysis. Mechanistic investigations based on spectroscopic measurements and quantum chemical calculations revealed a unique mechanism in which substrate-mediated hydrogen-atom transfer generates a light-active species that sustains NIR-driven turnover. Operating at the longest wavelength reported for a molecular photocatalyst, the platform establishes a distinct design principle for accessing photocatalytic reactivity beyond the traditional visible-light limit of homogeneous catalysts.