Copper (II) Complex Immobilized on Magnetic Nanoparticles Functionalized with Imine/Thio Ligand (Fe3O4@SiO2-Imine/Thio-Cu(II)): A Novel, Efficient and Reusable Nanomagnetic Catalysts for the Synthesis of 2,4,6-Triaryl Pyridines

Abstract

Herein we introduce a novel and reusable nanomagnetic copper catalyst (Fe3O4@SiO2-Imine/Thio-Cu(II)) constructed by immobilizing copper (II) complex on the surface of magnetic nanoparticles functionalized with Imine/Thio group. The structure of the as-constructed Fe3O4@SiO2-Imine/Thio-Cu(II) nanomaterial was well analyzed by a number of spectroscopic techniques including: FT-IR, SEM, TEM, EDX, XRD, VSM, AAS and ICP-OES. Experimental studies have well revealed that Fe3O4@SiO2-Imine/Thio-Cu(II) nanomaterial is an ecofriendly and efficient nanocatalyst for synthesis of 2,4,6-triaryl pyridines (82%–98%) via a C-N bond cleavage of benzylamines under aerobic oxidations in PEG at 120 °C. The grafting of the copper catalyst to the surface of magnetic nanoparticles has increased the catalytic activity of the material and also simplified catalyst recovery from the reaction mixture by an external magnet. The Fe3O4@SiO2-Imine/Thio-Cu(II) nanocatalyst was readily recovered by simple magnetic decantation and can be reused seven cycles without considerable loss in catalytic activity.