Fe3O4@SiO2@polyionene/Br3− core–shell–shell magnetic nanoparticles: a novel catalyst for the synthesis of imidazole derivatives under solvent-free conditions†
Abstract
New Fe3O4@SiO2@polyionene/Br3− core–shell–shell magnetite nanoparticles were prepared using a co-precipitation method and were used in the syntheses of imidazole derivatives under solvent-free conditions. The polyionene was easily prepared by reacting DABCO and 1,4-dibromo butane in DMF/methanol. It was then added to the previously formed layers and magnetic core–shell nanoparticles (P-MNPs) were functionalized. All the resultant nanoparticles were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and vibrating sample magnetometry (VSM). The catalyst was readily recovered by simple magnetic decantation and can be recycled several times with no significant loss of catalytic activity.