Visible-light-mediated Oxidative Amidation of Aldehydes Using a Magnetic CdS Quantum Dot as Photocatalyst.

A magnetic CdS quantum dot (Fe 3 O 4 /PDA/CdS) was synthesized through a facile and convenient method from inexpensive starting materials. The characterization of the prepared catalyst was performed by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray (EDX), and vibrating sample magnetometer (VSM) techniques. The Fe 3 O 4 /PDA/CdS was found to be a highly active photocatalyst for amidation of aromatic aldehydes with amines using air as a clean oxidant under mild conditions. The prepared photocatalyst can be recovered by magnetic separation and successfully reused for 5 cycles without considerable loss of its catalytic activit.