Supported ruthenium nanoparticles on polyorganophosphazenes: preparation, structural and catalytic studies

Supported Ru nanoparticles on a number of polyorganophosphazenes were prepared and tested for the hydrogenation of unsaturated compounds. The complex Ru(η6-cycloocta-1,3,5-triene)(η4-cycloocta-1,5-diene) was found to be a suitable precursor to deposit metallic nanoparticles on polyorganophosphazenes; upon the removal of cycloolefin ligands under hydrogen atmosphere, highly dispersed metal particles on the polymeric support can be obtained. Ru on polydimethylphosphazene was found to be an active catalyst for the hydrogenation of a wide range of unsaturated substrates (olefins, carbonyl compounds and aromatic compounds) under mild conditions. Polyorganophosphazenes are interesting in their ability to act as either soluble or insoluble catalyst supports, depending upon the dispersing liquid; thus, it is possible to operate in heterogeneous phase as well as in homogeneous phase. The reaction in homogeneous phase can be performed in environmental-friendly solvents such as alcohols and water. The catalyst exhibits high stability towards agglomeration. No significant change in the ruthenium nanoparticles surface as well as catalyst activity was observed.