Single Pd-S-x Sites In Situ Coordinated on CdS Surface as Efficient Hydrogen Autotransfer Shuttles for Highly Selective Visible-Light-Driven C-N Coupling

Selective synthesis of valuable secondary amines through N-alkylation of amines with alcohols is an important reaction in the modern industry but still remains a challenge in the chemical synthesis technique. Hereby, we report the visible-light-driven photocatalytic N-alkylation of aniline with benzyl alcohol over defined single PdSx species in situ coordinated on a CdS surface. Encouragingly, an aniline conversion of 100% and an almost 100% product selectivity toward the secondary amine N-benzylaniline are obtained with impressive H-2 production (11.8 mmol g(cat)(1) h(1)). The mechanistic studies reveal that the single PdSx species on the CdS surface can trap photogenerated electrons to endow them with a long lifetime to benefit the vibrational coupling of the hydrogen adsorption on PdSx species and then can serve as an efficient hydrogen autotransfer shuttle for the hydrogenation process toward the formation of the secondary amine N-benzylaniline. In addition, the present catalyst possesses good substrate tolerance for photocatalytic N-alkylation of different alcohols and substituted amines under optimized conditions. This work offers an alternative solar-driven catalytic system for the N-alkylation industry under mild conditions.