Palladium nanoparticles immobilized onto supported ionic liquid-like phases (SILLPs) for the carbonylative Suzuki coupling reaction

Crosslinked polymeric materials based on poly(ionic liquid)s, also named supported ionic liquid-like phases (SILLPs) were prepared by copolymerization of dication imidazole ionic liquids with divinylbenzene (DVB). Using the SILLPs-related polymeric materials as supports, palladium (Pd) metal nanoparticles were immobilized and stabilized, which can efficiently catalyze the carbonylative Suzuki coupling reaction of aryl iodides with aryl boronic acids, affording the corresponding products in good to excellent yields. The Pd nanoparticles immobilized onto SILLPs were characterized by transmission electron microscopy (TEM), thermogravimetric analysis (TG), and X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR). The size and dispersion of the Pd nanoparticles supported on polymers are influenced possibly by varying the contents of the ionic liquid units and the introduction of amine groups. Furthermore, hot filtration and mercury poisoning tests indicated that the palladium species leached into the solvent during the reaction and returned to the polymers after the reaction was completed. In addition, the catalyst was easily recovered from the reaction mixture by filtration and reused over five consecutive cycles without a significant decrease in its activity.