Synthesis and characterization of Schiff base complex of Pd(II) supported on superparamagnetic Fe3O4@SiO2 nanoparticles and its application as an efficient copper- and phosphine ligand-free recyclable catalyst for Sonogashira–Hagihara coupling reactions

Superparamagnetic nanoparticles functionalized with Schiff base complex of Pd (II) were simply synthesized by a two-step method. The catalyst was characterized by X-ray powder diffraction (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), dynamic light scattering (DLS),vibrating sample magnetometry (VSM), Fourier transform infrared (FT-IR), and N2 adsorption–desorption isotherm analysis. Also, its Pd content was determined by Inductively Coupled Plasma (ICP) analyzer. The immobilized palladium complex was used as an efficient catalyst for copper- and phosphine ligand-free Sonogashira reaction of aryl halides with phenylacetylene. This catalyst shows notable advantages such as simplicity of operation, excellent yields, short reaction times, heterogeneous nature, easy magnetically work up and recyclability.