Facile method for the synthesis of core/shell Fe3O4@SiO2@SiO2-SH-Au: a super magnetic nanocatalyst for water-medium and solvent-free alkyne hydration

In a simple approach, gold was successfully anchored to the surface of thiol-functionalized super paramagnetic Fe3O4 nanoparticles as heterogeneous catalyst. The core/shell Fe3O4@SiO2@SiO2-SH-Au was prepared in a facile procedure, without using any reducing reagents by in situ reduction of Au3+. The catalyst was characterized by TEM, SEM, IR, XRD and EDX. The catalyst with loaded iron oxide nanoparticles can be recovered from the reaction mixture by an external magnet and reused without considerable decrease in activity even after four runs. As demonstrated experimentally, the catalyst shows remarkably high catalytic efficiencies in promoting water-medium and solvent-free alkyne hydration reaction.