Palladium particles from oxime-derived palladacycle supported on Fe3O4/oleic acid as a catalyst for the copper-free Sonogashira cross-coupling reaction

An oxime-derived palladacycle was synthesized using 4-bromobenzoxime and pyridine in CHCl3, and characterized by FT-IR and 1H NMR spectroscopy. This Pd complex was supported on Fe3O4/oleic acid and shown to be an efficient catalyst for the copper-free Sonogashira cross-coupling reaction of various aryl halides with phenylacetylene in air and in ethanol or mixed aqueous medium. The oxime-derived palladacycle gave highly active palladium nanoparticles for the organic synthesis. The coupling products were obtained in high yields with low Pd loading and the heterogeneous catalyst can be separated by an external magnet and reused six times without loss of its activity. The characterization of the catalyst was carried out by XRD, SEM and TEM. Both TEM and XRD revealed that the palladium nanoparticles were well dispersed with diameters from 5 to 10 nm and average size 9.97 nm.

Graphical AbstractThis review presents a Pd catalyst on the surface of Fe3O4/oleic acid for copper-free Sonogashira cross-coupling. Very small amounts of the catalyst catalyzed the Sonogashira reaction in ethanol and water-organic solvent mixtures.Figure optionsDownload as PowerPoint slide