Fe3O4@OA-Pd and Mo10V2@NSiO2 nanoparticles: an efficient and reusable catalytic system for Heck reaction under ligand free conditions

This paper reports the use of a novel catalytic system composed of H5PMo10V2O40 supported on nano silica (Mo10V2@NSiO2) and palladium-deposited, oleic-acid-coated Fe3O4 (Fe3O4@OA-Pd) nanoparticles, as reusable catalysts for Heck coupling reaction under ligand and base free conditions. The average particle size of catalyst was measured to be about 9 nm by transmission electron microscopy. The immobilized palladium on oleic acid coated Fe3O4 was found to be effective in the Heck arylation of various aryl bromides and especially less reactive aryl chlorides with styrene in the presence of heteropoly acid. This method has the advantages of high yields, elimination of ligand and base, simple methodology and easy workup. Interestingly, the novel catalytic system could be recovered in a facile manner from the reaction mixture and recycled several times without any significant loss in catalytic activity. Structural changes of recovered Mo10V2@NSiO2 and Fe3O4@OA-Pd were investigated before reusing for the next runs. Finally, synchronized reusability of both components of our catalytic system has been investigated in the model reaction.