Pd@dppe@Fe3O4 as a magnetically recyclable catalyst for C–C bond formation: efficient phenylation of aldimines under mild conditions

Novel separable nanomagnetic organometallic catalysts were synthesized by different processes through the immobilization of palladium salt on Fe₃O₄ MNPs bearing a phosphine ligand. These nanomagnetic particles were characterized by energy-dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), differential thermal analysis (DTA), X-ray diffraction (XRD), and vibrating-sample magnetometer (VSM) analysis. The resulting Pd@dppe@Fe₃O₄ nanocatalysts efficiently promoted the 1,2-addition of phenylboronic acid to aldimines, delivering the corresponding secondary amines in yields of up to 98 % after 10 h. This catalyst could be readily recovered by magnetic separation and reused without significant loss of activity.