Palladium(II) anchored on polydopamine coated-magnetic nanoparticles (Fe3O4@PDA@Pd(II)): A heterogeneous and core-shell nanocatalyst in Buchwald-Hartwig C-N cross coupling reactions

An efficient method was proposed to synthesize polydopamine (PDA)-coated Fe3O4 nanoparticles (Fe3O4@PDA). For the first time, effective deposition of Pd complex is explained by using Fe3O4@PDA as a core-shell magnetic coordinator and stabilizer agent. In this method, palladium ions were adsorbed on Fe3O4@PDA surfaces through immersion of the Fe3O4@PDA into a palladium plating bath. The structure, morphology and physicochemical features of the prepared particles were studied using various analytical methods including high resolution transmission electron microscopy (HR-TEM), field emission scanning electron microscope (FESEM), energy-dispersive X-ray spectroscopy (EDS), vibrating sample magnetometer (VSM), X-ray photoelectron spectroscopy (XPS), inductively coupled plasma (ICP), thermogravimetric analysis (TGA) and FT-IR spectroscopy. Core-shell Fe3O4@PDA/Pd(II) nanoparticles showed excellent catalytic performance as a reusable nanocatalyst in Pd-catalyzed Buchwald-Hartwig C-N cross coupling reaction. A variety of aryl amines were prepared through reaction of aryl halides (chloride, bromide and iodide) and amines in high yields. The catalyst can be recycled and reapplied up to six cycles with no considerable change in its catalytic activity. (C) 2018 Elsevier Ltd. All rights reserved.