Palladium nanoparticles supported on modified crosslinked polyacrylamide containing phosphinite ligand: A novel and efficient heterogeneous catalyst for carbon-carbon cross-coupling reactions

A novel palladium catalyst based on modified crosslinked polyacrylamide containing phosphinite ligand was synthesized and characterized. It exhibits excellent activity and stability in Mizoroki-Heck and Suzuki-Miyaura cross-coupling reactions with different aryl halides including inactive aryl chlorides. Short reaction times with good to excellent yields of the desired products express the effectiveness of this catalyst in these reactions. Transmission electron microscopy (TEM) shows that palladium particles are well-dispersed and of typical diameter of 18-30 nm. The X-ray powder diffraction (XRD) pattern of the Pd catalyst is consistent with the metallic Pd(0). The turnover number (TON) of this catalyst reaches up to 9.5 x 10(4) for these C-C bond forming reactions. Elemental analysis of Pd by ICP-OES and hot filtration test shows low leaching of the metal into solution from the supported catalyst which confirms the full heterogeneous character of the catalytically active species. The catalyst can be used many times in repeating cycles without considerable loss in its activity. (C) 2010 Elsevier B.V. All rights reserved.