Palladium(0) nanoparticles formed in situ in the Suzuki-Miyaura reaction: The effect of a palladium(II) precursor

Two palladium catalyst precursors were prepared by immobilizing PdCl(2) and Pd(OAc)(2) on cyclohexyldiamine-modified glycidyl methacrylate polymer (GMA-CHDA) and used in the Suzuki-Miyaura reaction (80 degrees C, 2 h) without any pre-treatment. Using the TEM, SEM, EDS, and XPS methods, we were able to characterize the Pd(0) nanoparticles formed in situ during the catalytic process. The catalyst obtained from Pd(OAc)(2) (P(2)) contained Pd(0) nanoparticles with a diameter of 3-5 nm, whereas much bigger agglomerates were found for P(1), which had been obtained from PdCl(2). The P(2) catalyst exhibited much better catalytic performance than PI. pointing to an important role of the palladium precursor in the preparation of the catalyst. (C) 2010 Elsevier B.V. All rights reserved.