Metal nanoparticles stabilized by functionalized hyperbranched polymers for catalysis

Catalytic activity of metal nanoparticles has received attention in homogeneous catalysis. The rate and selectivity of homogeneous catalysis using organometallic complexes are controlled by appropriate design of auxiliary ligands bound to the metal center. For nano sized metal particles, they could be accomplished by appropriate design of the polymer supports with unique structures and properties. Hyperbranched polymers are one of the dendritic polymers, having unique features they received by facile one-pot preparation of monomers and existence of large numbers of functional groups. We found that hyperbranched polystyrenes bearing organoammonium groups are found to be a new polymer support for nano metal particle catalysts of gold, palladium, and platinum. By judicious choice of the R group, both water- and organo-soluble HPS-NR₃⁺Cl^- can be prepared. The resulting M@HPS-NR₃⁺Cl^- behaves as biphasic catalysts for several organic reactions. Since thin-films of Pd@HPS-NR₃ ⁺Cl^- can be made with ease, electroless plating of nickel and copper is possible on the surface of solid materials including plastic and ceramics.