Palladium nanoparticles supported on magnetic organic-silica hybrid nanoparticles

A method for supporting palladium nanoparticles on magnetically separable organosilica nanoparticles functionalized with ionic liquid groups is described. The system was prepared by sol-gel condensation of two silica precursors: tetraethyl orthosilicate (TEOS) and bis-silylated ionic liquid monomer, on hydrophobic magnetic nanoparticles modified with oleate groups. The support of palladium nanoparticles on the magnetic organo-silica hybrid nanoparticles was achieved by adsorbing palladium salts (Na₂PdCl₄) on their surface via ion exchange with the ionic liquid groups, followed by reduction with sodium borohydride. The resulted system was applied in three different catalytic transformations: carbonylation of iodoarenes and Heck and Suzuki coupling reactions. The catalyst demonstrated high catalytic activity and was easily separated from the reaction mixture by applying an external magnetic field. The catalyst was recycled over five times without showing a significant loss in its activity.