Highly dispersed rhodium/polyphosphine metal catalysts: Preparation and characterization

The preparation of novel rhodium metal catalysts, dispersed on styrene-2% divinylbenzene copolymer, functionalized with phosphine groups, is reported. The reduction temperature was chosen on the basis of temperature programmed reduction (TPR) experiments. Thermogravimetric analysis (TGA) indicates that the polymeric network in these materials is stable up to 473 K. The physical properties of the metallic phase were determined with X-ray scattering techniques (SAXS and WAXS). These techniques showed that the metal particle size and dispersion were determined mostly by the number of phosphine groups present on the support. This suggested the existence of a strong metal-ligand interaction. This fact was confirmed by an infrared study of CO absorption onto the catalysts. All polyphosphine supported samples showed CO bands which were assigned to polymer-anchored PRh(CO)2 moieties.