Preparation and characterization of HypoGel-supported Pd nanocatalysts for Suzuki reaction under mild conditions

A new heterogeneous catalyst composed of Pd nanoparticles immobilized within a HypoGel resin has been prepared in the absence of any ligands using an extensive cross-linking method. This newly developed nanocatalyst was characterized by N2 adsorption-desorption, X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), Fourier transform infrared spectroscopy and inductively coupled plasma-mass spectrometer (ICP-MS) techniques. TEM and XRD results revealed that the Pd nanoparticles were well dispersed with diameters in the range of 4–12 nm, and an average size of about 8 nm. The cross-linked Pd catalyst demonstrated excellent catalytic activity towards the synthesis of a series of biaryl compounds by the reaction of various aryl halides (e.g., bromides andiodides) with phenylboronic acid in the presence of tetrabutylammonium bromide. ICP-MS analysis indicated that there was only 0.25% weight loss of Pd (0.55 ± 0.02 ppm) from the supported catalyst after the first cycle reaction. Furthermore, the catalyst showed excellent reusability (up to five uses) with consistently high levels of catalytic activity following its recovery by filtration.

A new heterogeneous catalyst has been developed by the immobilization of Pd nanoparticles on a HypoGel resin using an extensive cross-linking method, and the catalyst exhibited excellent catalytic activity in the Suzuki reaction.Figure optionsDownload as PowerPoint slide