Facile Microwave-Assisted Synthetic Approach to Palladium Nanoparticles Supported on Copper Oxide as an Efficient Catalyst for Heck and Sonogashira Cross-Coupling Reactions

Abstract

A simple green one-step method for the synthesis of highly active palladium nanoparticles embedded on copper oxide as an efficient catalyst for ligand-free Heck and Sonogashira cross-coupling reactions has been developed. The synthetic approach is based on Microwave (MW)-assisted simultaneous chemical reduction of an aqueous solution of palladium and copper salts using hydrazine hydrate as the reducing agent. Selected characterization of the catalyst with transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction spectroscopy (XRD) reveal a size range of 25[Formula: see text][Formula: see text][Formula: see text]2[Formula: see text]nm for the generated catalyst nanoparticles with the highest catalytic activity. The use of the generated Pd/CuO nanoparticles is highly advantageous due to the use of ethanol/water as an environmentally green solvent under mild reaction conditions. Furthermore, the synthesized Pd/CuO nanoparticles catalyst can be recycled and re-used up to five times with negligible effect on the efficiency having turnover number up to 6000 and turnover frequency reaching 72[Formula: see text]000[Formula: see text]h[Formula: see text] for 20[Formula: see text]wt.% Pd loaded catalyst at 150∘C.