Pd Nanoparticles Immobilized on Nanosilica Triazine Dendritic Polymer: A Reusable Catalyst for the Synthesis of Mono-, Di-, and Trialkynylaromatics by Sonogashira Cross-Coupling in Water

Palladium nanoparticles immobilized on nano-silica triazine dendritic polymer (Pdnp-nSTDP) was found to be a highly effective catalyst for the Sonogashira cross-coupling of aryl halides (iodides, bromides, and chlorides) with aromatic and aliphatic terminal alkynes. This reaction was best performed in water as a green solvent in the presence of just 0.01 mol% of the catalyst at room temperature. Efficient synthesis of V- and star-shaped polyalkynylated molecules with a benzene, pyridine, or pyrimidine central core was also achieved through Sonogashira cross-coupling of dihalo and trihalo aromatics with terminal alkynes in the presence of this catalytic system. The Pd-np-nSTDP catalyst was easily recovered and reused several times without significant loss of reactivity.