e describe the synthesis of a novel Fe3O4/amidoxime (AO)/Pd nanocatalyst by grafting of AO groups on Fe3O4 nanoparticles and subsequent deposition of Pd nanoparticles. Prior to grafting of AO, the 2-cyanoethyl-functionalized Fe3O4 nanoparticles prepared through combining 2-cyanoethyltriethoxysilane and Fe3O4 were treated with hydroxylamine. The AO-grafted Fe3O4 nanoparticles were then used as a platform for the deposition of Pd nanoparticles. The catalyst was characterized using Fourier transform infra- red spectroscopy, X-ray diffraction, scanning and transmission electron microscopies, vibrating sample magnetometry, wavelength- and energy-dispersive X-ray spectroscopies and inductively coupled plasma analysis. Fe3O4/AO/Pd is novel phosphine-free recyclable heterogeneous catalyst for Sonogashira reactions. Interestingly, the novel catalyst could be recovered in a facile manner from the reaction mixture by applying an external magnet device and recycled seven times without any signif- icant loss in activity.
