A Cobaloxime–Polyoxometalate Conjugate for Enhanced Photocatalytic Tertiary Amine Synthesis

Functional tertiary amines play a critical role in the synthesis of key building blocks for agrochemicals and pharmaceuticals, driving demand for direct and versatile methods for producing them from common feedstocks like olefins and amines. Despite their significance, efficient coupling reactions for their synthesis remain scarce. Here, we present a novel photocatalytic system featuring a covalently linked cobaloxime–polyoxometalate (Co-POM) catalyst electrostatically paired with cationic photosensitizers. This assembly enables efficient and site-selective synthesis of tertiary amines via photoredox-generated aminium radical cations, promoting effective charge separation and transfer. Notably, when using cyclohexanone derivatives, subsequent dehydration and dehydrogenation steps lead to aromatic amine formation. Mechanistic insights from ultrafast transient absorption, EPR, and time-resolved fluorescence spectroscopy underscore the system’s enhanced catalytic activity and demonstrate the promise of metal catalyst-linked POMs for advanced photocatalytic synthesis.