Secondary Phosphine Oxide-Stabilized Pd Nanoparticles: Ligand-Controlled Chemoselective Hydrogenation of Nitro Compounds toward Amines in Water.

A novel approach to the catalytic synthesis of aromatic amines using secondary phosphine oxides (SPO) supported on palladium nanoparticles is described. In this method, the ligand modulates the chemoselectivity of the target product in aqueous conditions. The catalyst demonstrated exceptional synergistic effects with water in the selective catalytic hydrogenation of nitro compounds and nitrogen heterocycles. The presence of water and ligand is expected to enhance substrate uptake and facilitate the synergistic activation of molecular hydrogen on the surface of palladium nanoparticles. This method allows for the efficient preparation of aromatic amines, achieving good to high yields with excellent chemoselectivity. The recovery of the catalysts was achieved by leveraging the heterogeneity of water, thereby ensuring the maintenance of high reaction efficiency.