Pd(II) supported dioxime functionalized Fe3O4 nanoparticles as efficient, eco-friendly and reusable catalysts for the Suzuki-Miyaura cross-coupling reaction in water

Five novel dioxime ligands (L(1-5)H2) were synthesized in various yields under suitable conditions. Novel nano-Fe3O4-supported compounds (Fe3O4/L(1-5)) based on dioxime ligands were also prepared. Subsequently, hybrid materials Fe3O4/L(1-5)/Pd(II) were fabricated by the reaction of Fe3O4/L(1-5) with Pd(AcO)(2) in acetonitrile. All synthesized nanoparticles were characterized by FT-IR spectroscopy, scanning electron microscopy (SEM), energy dispersive X-Ray analysis (EDX), X-ray diffraction (XRD), inductively coupled plasma analysis (ICP), differential scanning calorimetry (DTA), and thermogravimetric analysis (TGA). The spectroscopic results show that the magnetite (Fe3O4) nanoparticles are in nano size since crystal sizes are < 100 nm. The particles have an average size of about 9.4-23.3 nm. The powder XRD confirmed that the synthesized Fe3O4, Fe3O4/L(1-5), and Fe3O4/L(1-5)/Pd(II) MNPs possess cubic structure having the lattice parameter between 8.31 and 8.40 A. The structure and the lattice parameters are in good agreement with the literature reported data. The Fe3O4/L(1-5)/Pd(II) nanocatalysts showed high activities in the Suzuki-Miyaura cross-coupling of different aryl halides including iodides, bromides and even chlorides with phenylboronic acid under green and aerobic conditions. More importantly, the reusability experiments revealed that Fe3O4/L(1-5)/Pd(II) catalysts were durable by almost maintaining their inherent activity after 5 catalytic cycles. (c) 2019 Elsevier B.V. All rights reserved.