Bimetallic Pd‐Sn Nanocatalysts for Selective Synthesis of Amines and Imines in Water.

Aided by our interest in green chemistry, we report the synthesis of a novel Pd‐Sn nano catalyst for C−N coupling reaction in water. The catalyst has been synthesized by a simple wet chemical reduction method and fully characterized by a library of physico‐chemical techniques such as Powder X‐Ray Diffraction (PXRD), High Resolution Transmission Electron Microscopy (HRTEM), X‐Ray Photo Electron Spectroscopy (XPS) and UV‐Vis spectroscopy, Field Emission Scanning Electron Microscopy (FESEM), Energy Dispersive X‐Ray (EDX) spectroscopy, and Inductively Coupled Plasma Optical Emission Spectroscopy (ICP‐OES). The robust Pd‐Sn catalyst shows high catalytic efficiency for the oxidative coupling of benzylamines and tandem coupling between alcohol and amine in water as solvent to give rise to the corresponding secondary amines. However, in presence of oxygen both the reactions stop at the imine stage. As a result, we could guide the reaction to obtain selectively amine or imine. The high efficiency, recyclability and good substrate scope of this Pd‐Sn nanocatalyst is noteworthy. Preliminary mechanistic studies indicated that the reactions proceed via initial activation of N−H bond of amine [ABSTRACT FROM AUTHOR]