Anchoring Cu (II) on  Fe3O4@SiO2/Schif base: a green, recyclable, and extremely eicient magnetic nanocatalyst for the synthesis of 2‑amino‑4H‑chromene derivatives

Abstract

In this work, a novel water-soluble Salen type Cu(II) Schif base complex functionalized silica-coated magnetite nanoparticles [Fe 3 O 4 @SiO /Schif base of Cu(II)] was synthesized and characterized. First, an immobilized water-soluble Schif base was synthesized from the condensation reaction between 3-amino propyl triethoxy silane (APTES) functionalized silica-coated magnetite nanoparticles and a water-soluble aldehyde (sodium salicylaldehyde-5-sulfonate monohydrate). After that, functionalized Schif base was converted to functionalized Cu(II) Schif base complex as the result of reaction with Cu(II) acetate tetrahydrate. The structural and magnetic properties of the prepared compounds were identiied by FT-IR, XRD, SEM, EDX, TEM, VSM, and TGA. The catalytic activity of the novel nanocatalyst was investigated for the preparation of 2-amino-4H-chromene derivatives through an one-pot, three-component reaction of dimedone, aromatic aldehydes, and malononitrile, in the presence of catalytic amounts of the Fe 3 O 4 @SiO 2 2 /Schif base of Cu(II) nanocatalyst in water and at room temperature. The 2-amino-4H-chromene derivatives were obtained in good to excellent yields. Furthermore, because of the solubility of metal Schif base complexes in water, the nanocatalyst dispersed in water easily without using ultrasonic or shaker.