Palladium nanoparticles immobilized on multifunctional ‎hyperbranched polyglycerol-grafted magnetic nanoparticles as a ‎sustainable and efficient catalyst for C-C coupling reactions

This study offers an exclusive class of magnetic nanoparticles supported hyperbranched polyglycerol (MNP/HPG) that was functionalized with citric acid (MNP/HPG-CA) as a host immobilization of palladium nanoparticles. The MNP/HPG-CA/Pd catalyst was fully characterized using some different techniques such as thermogravimetric analysis (TGA), x-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy-dispersive x-ray spectroscopy (EDX), inductively coupled plasma (ICP) and x-ray photoelectron spectroscopy (XPS). The new catalytic system showed high activity for the Suzuki–Miyaura cross-coupling and Heck reaction under mild and green conditions. Besides, the MNP/HPG-CA/Pd was found to be a convenient catalyst for copper-free Sonogashira coupling reaction in water as a green solvent at room temperature. Moreover, the catalyst could be recovered easily and reused several times without significant loss of reactivity. Ease of preparation, oxygen insensitive, phosphine-free, air- and moisture-stable, and high reusability of this immobilized palladium catalyst are the noteworthy advantages of this catalytic system.