Synthesis and characterization of Cu(II) Schiff base complex immobilized on graphene oxide/α-Fe2O3 as heterogeneous catalyst for the three-component synthesis of 2-Amino-4H-Chromenes derivatives and dye reduction

[Display omitted] •Copper (II) complex immobilized on amine-functionalized graphene oxide (GO).•The complex as a catalyst for the synthesis of 2-amino 4H-benzo[h]choromenes and the reduction of 4-nitrophenol and methylene blue.•The catalyst can be recovered and reused six times without remarkable loss in its activity. A magnetic graphene oxide (MGO) tethered Cu(II) Schiff base complex, GO/α-Fe2O3/CuL, was prepared through a stepwise procedure. The structural and morphological characterization of the synthesized nanostructure was carried out using various techniques FT-IR, SEM, TGA, EDX, Raman, BET, VSM, ICP, XRD and VSM analyses. The catalytic activity of the GO/α-Fe2O3/CuL nanostructure was examined for the synthesis of 2-amino 4H-benzo[h]choromenes via three-component one-pot reaction of 1-naphtol, malononitrile and aldehyde under solvent-free conditions. The short reaction time, high product yield, and easy separation from the reaction environment are the benefits of this catalytic system. Also, the synthesized nanostructure indicated catalytic activity in the reduction of 4-nitrophenol and methylene blue using NaBH4 at room temperature in an aqueous media. The reaction progress was monitored by UV–vis spectroscopy. GO/α-Fe2O3/CuL as catalyst could be recovered easily from the reaction mixture by an external magnet and reused for six times without remarkable loss in its activity.