Fabrication of PEI grafted Fe₃O₄/SiO₂/P(GMA-co-EGDMA) nanoparticle anchored palladium nanocatalyst and its application in Sonogashira cross-coupling reactions

Novel magnetic Fe₃O₄/SiO₂/P(GMA-co-EGDMA) composite nanoparticles grafted with hyperbranched/linear polyethylenimine ligands were fabricated. Subsequently, nano palladium was effectively anchored on this carrier through complexation between Pd²⁺ ions and multifunctional organic ligands, then a novel supported Pd nanoparticle catalyst with good dispersion and high loading of Pd nanoparticles was successfully prepared after the following reduction process. Afterwards, the as-prepared supported Pd nanoparticle catalyst was characterized by SEM, TEM, XRD, FTIR, TG and ICP-AES. Ultimately, the catalytic performance of the supported Pd nanoparticle catalyst was investigated by catalysing the Sonogashira cross-coupling reaction between aryl halides and arylacetylene. Research shows that the novel supported Pd nanoparticle catalyst exhibits very superior catalytic activity in catalysing the Sonogashira cross-coupling reaction between aryl halides and arylacetylene, even in the absence of the cocatalyst (CuI), and the side reaction producing the by-product (1,3-diyne) can be inhibited effectively. In addition, this supported Pd nanoparticle catalyst exhibits stable recovery and high catalytic activity, for it can be effectively reused 8 times without obvious loss of catalytic activity. Furthermore, the yields of the target products of the Sonogashira cross-coupling reaction between iodobenzene and phenylacetylene, 3-aminophenylacetylene and 4-(ethynyl)phthalic anhydride can reach approximately 79%, 78% and 95% after this novel supported Pd nanoparticle catalyst has been used eight times, respectively.