SELECTIVITY OF POLYAMIDE-SUPPORTED RHODIUM CATALYSTS IN THE ADDITION OF HYDROSILANES TO VINYL COMPOUNDS

A series of polyamides containing aromatic or heteroaromatic and aliph atic fragments in their repeat unit were synthesized and used as suppo rts to immobilize a catalyst based on a [RhCl(CO)(2)](2) precursor. Th e polymeric materials were characterized by differential scanning spec troscopy (DSC), wide-angle X-ray scattering (WAXS), small-angle X-ray scattering (SAXS), specific surface area and porosity measurements. Th e catalytic properties of polyamide-supported Rh(I) catalysts were stu died in hydrosilylation of vinyl-type olefins. The selectivity of this reaction towards formation of the linear adducts over the branched on es was found to be greatly influenced by the matrix supramolecular str ucture when compared with that in the homogeneous phase. Based on SAXS measurements, the high selectivity of the polymer-immobilized rhodium catalysts was attributed to the matrix microporous structure displayi ng a narrow distribution of pores mostly in the range from r = 1.0 to 3.0 nm.