Abstract
Ni nanoparticles(NiNPs)were prepared by thermal decomposition of nickel acetylacetonate in the presence of a third generation polypyridylphenylene dendrimer(G3)which acts both as a coordinating ligand due to presence of pyridine groups and as a stabilizing agent due to highly branched architecture.Transmission electron microscopy(TEM),high resolution transmission electron microscopy(HRTEM),and X-ray photoelectron spectroscopy(XPS)were used to extensively evaluate structure and morphology of the synthesized NiNPs@G3.The selected area electron diffraction(SAED)allowed us to conclude about fcc structure of NiNPs while STEM EDS analysis demonstrated a formation of core-shell NiO@Ni NPs.Further,the catalyst was tested in selected Suzuki-Miyaura cross-coupling reactions at mild conditions and demonstrated a high efficiency at low Ni loading with negligible content of Ni0 on the NP surface.The functional hyperbranched dendrimer macromolecule provided an excellent stabilization for NiNPs@G3 while allowing an easy access for reactants to catalytic sites.The high activity of the catalyst in the recycling experiments was maintained by the absence of Ni leaching from the NiNPs@G3.
NSTL