One-pot reductive amination of aldehydes with nitroarenes using formic acid as the hydrogen donor and mesoporous graphitic carbon nitride supported AgPd alloy nanoparticles as the heterogeneous catalyst

Herein, we report a one-pot protocol for the synthesis of secondary amines via a tandem reductive amination of aldehydes with nitroaromatics utilizing mesoporous graphitic carbon nitride (mpg-C3N4) supported AgPd alloy nanoparticles (mpg-C3N4/AgPd) as the catalyst, FA as the hydrogen donor and water as the sole solvent, which is a protocol in harmony with the green chemistry rules. In the present one-pot catalytic reductive amination protocol, a variety of secondary amines (11 examples) were yielded by using nitroarenes as a nitrogen source and benzaldehyde in the presence of the mpg-C3N4/AgPd nanocatalyst, which is the first example in the literature. Monodisperse AgPd alloy NPs (2.5 +/- 0.5 nm) were synthesized by using our established protocol via the co-reduction of silver(i) acetate and palladium(ii) acetylacetonate in the presence of oleylamine and oleic acid as surfactants in a hot organic solvent. The as-prepared AgPd alloy nanoparticles were then deposited on mpg-C(3)N(4)via a liquid phase self-assembly method. After the structural characterization of the mpg-C3N4/AgPd nanocatalyst using TEM, PXRD, BET and ICP-MS analyses, they were directly tested in one-pot direct reductive amination reactions in which they showed superior activity. The applicability of the present one-pot reductive amination strategy was demonstrated over a variety of aldehydes and nitroarenes (11 examples). Moreover, the mpg-C3N4/AgPd catalyst was a reusable catalyst in the reductive amination reactions providing 99% yield even after five consecutive runs.