Synthesis of Fe3O4 Microspheres-Supported Catalysts for Suzuki Coupling Reaction

Two new Fe3O4 microspheres-supported semi-homogeneous catalysts, namely Fe3O4-G4-polyaminoamido (PAMAM) dendrimers-Pd(0) and Fe3O4-polyethylene glycols (PEGs)-Pd(0) were synthesized and characterized by X-ray powder diffraction, infrared spectrum, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy and thermal gravimetric analysis, which can catalyze Suzuki coupling reactions. The performance of catalysts was tested for the reactions of aryl halides with phenyl boronic acid and compared with a heterogeneous catalyst Fe3O4-(3-aminopropyl)triethoxysilane (APTS)-Pd(0), in which Fe3O4-G4-PAMAM dendrimers-Pd(0) shows the best activity among the three catalysts. The order of the catalytic activities is Fe3O4-G4-PAMAM dendrimers-Pd(0)> Fe3O4-PEGs-Pd(0)> Fe3O4-APTS-Pd(0). The catalysts can be quickly and completely recovered by simply applying a magnet of 105 mT and the efficiencies remain unaltered even after four recycles.