Synthesis and Characterization of Copper (II) and Nickel (II) Immobilized on Silica- Coated Copper Ferrite: As Novel Magnetically Reusable Nano Catalysts Towards Reduction of Nitroarenes with NaBH4

Abstract

Aim and Objective: Nowadays, the design, synthesis and application of magnetically nanocomposite systems have attracted the attention of numerous scientists. The huge surface area and magnetic characteristic of nanoparticles as well as the inherent potentiality of the used metal species, makes them susceptible to have different reactivity in chemical reactions. In this context, we therefore encouraged to prepare a new design of magnetic nanocatalysts as CuFe2O4@SiO2@AAPTMS@Ni(II) and CuFe2O4@SiO2@AAPTMS@Cu(II) followed by monitoring of their catalytic activities towards reduction of nitroarenes with NaBH4. Materials and Methods: Magnetically nanoparticles of CuFe2 O4@SiO2@AAPTMS@Ni(II) and CuFe2O4@SiO2@AAPTMS@Cu(II) were prepared through a four-step procedure: i) preparation of CuFe2O4 MNPs, ii) coating of CuFe2O4 nucleus by silica-layer using tetraethyl orthosilicate (TEOS), iii) layering of CuFe2O4@SiO2 MNPs with [3-(2-aminoethylamino)propyl] trimethoxysilane (AAPTMS), and iv) the complexation of CuFe2O4@SiO2@AAPTMS MNPs with an aqueous solution of Ni(OAc)2·4H2O or Cu(OAc)2·H2O. Results: The catalytic activity of CuFe2O4@SiO2@AAPTMS@Ni(II) and the Cu(II)-analogue towards reduction of nitroarenes with NaBH4 was studied. The examinations resulted that using a molar ratio of 1:2 for ArNO2 and NaBH4 in the presence of 20 mg of nanocomposites in H2O under reflux conditions reduces various aromatic nitro compounds to arylamines in high yields. Conclusion: The immobilization of Ni(II) and Cu(II) species on silica-layered CuFe2O4 was investigated. Magnetically nanoparticles of CuFe2O4@SiO2@AAPTMS@Ni(II) and the Cu(II)-analogue showed the perfect catalytic activity towards reduction of nitroarenes with NaBH4 in H2O. All reactions were carried out within 2– 15 min to afford aniline products in high yields.