Palladium immobilized on amidoxime‐functionalized magnetic Fe 3 O 4 nanoparticles: a highly stable and efficient magnetically recoverable nanocatalyst for sonogashira coupling reaction

We describe the synthesis of a novel Fe 3 O 4 /amidoxime (AO)/Pd nanocatalyst by grafting of AO groups on Fe 3 O 4 nanoparticles and subsequent deposition of Pd nanoparticles. Prior to grafting of AO, the 2‐cyanoethyl‐functionalized Fe 3 O 4 nanoparticles prepared through combining 2‐cyanoethyltriethoxysilane and Fe 3 O 4 were treated with hydroxylamine. The AO‐grafted Fe 3 O 4 nanoparticles were then used as a platform for the deposition of Pd nanoparticles. The catalyst was characterized using Fourier transform infrared spectroscopy , X‐ray diffraction, scanning and transmission electron microscopies, vibrating sample magnetometry, wavelength‐ and energy‐dispersive X‐ray spectroscopies and inductively coupled plasma analysis. Fe 3 O 4 /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 significant loss in activity. Copyright © 2015 John Wiley & Sons, Ltd.