Selective and recyclable rhodium nanocatalysts for the reductive N-alkylation of nitrobenzenes and amines with aldehydes

Rhodium nanocatalysts were prepared and applied for the reductive N-alkylation of nitrobenzenes and amines to the corresponding secondary amines with aldehydes and ketones. Functional nitrobenzenes, such as nitrobenzenes with F, Cl, Br, CH₃O and CH₃ were transformed to the corresponding secondary amines in good to excellent yields. Moreover, the Rh@CN catalyzed N-alkylation of a series of primary amines with aldehydes and ketones also gave the corresponding secondary amines in high yields. The Rh@CN is heterogeneous, and can be reusable several times (at least 4 times) for the reductive N-alkylation of nitroarenes.