Supercritical carbondioxide deposition of gamma-Alumina supported Pd nanocatalysts with new precursors and using on Suzuki-Miyaura coupling reactions

New non-fluorinated precursors (Pd(PTQD)(2) and Pd(DGM)(2)) derived from Pd(II) complexes of dimethylglioxime (DMG) and phenanthrenequinonedioxime (PTQD) were used for supercritical carbondioxide deposition of Pd on gamma-Alumina support. Homogeneous well-dispersed Pd nanoparticles on gamma-Alumina with a size range of 2 nm (for Pd(PTQD)(2)) and 7 nm (for Pd(DGM)(2)) were detected with HR-TEM micrographs. Moreover, XRD analysis showed that the synthesized structures were composed of cubic and octahedral crystals as Pd and PdHX nanoparticles with a high ratio of PdHX. Then, the prepared nanoparticles were used as catalysts for Suzuki-Miyaura reactions of bromobenzene and phenylboronic acid in two different solutions of n-methyl-2-prolydon and dimethylformamide at 60 degrees C. Two bases K2CO3 and Na2CO3 were used to observe their interactions with the catalysts. For all cases, catalysts prepared from Pd(PTQD)(2) showed better performance. This is attributed to the smaller particle size distribution in Pd(PTQD)(2) than Pd(DMG)(2) catalysts.