Catalysis Letters, Vol.150, No.3, 683-701, 2020
New Copper Complex on Fe3O4 Nanoparticles as a Highly Efficient Reusable Nanocatalyst for Synthesis of Polyhydroquinolines in Water
In this work, we present a simple, environmentally friendly and economical route for the preparation of a novel copper-Schiff-base organometallic complex on Fe3O4 nanoparticles (Fe3O4@Schiff-base-Cu) using an inexpensive and simple method and available materials. This magnetic nanocatalyst was comprehensively characterized using Fourier transform infrared spectroscopy (FT-IR), X-Ray Diffractometer (XRD), inductively coupled plasma atomic emission spectroscopy (ICP), energy-dispersive X-ray spectroscopy (EDS), scanning electron microscopy (SEM), X-ray mapping, thermogravimetric analysis (TGA) and vibrating sample magnetometer (VSM) analysis. In the second stage, the catalytic activity of this catalyst was studied in the synthesis of polyhydroquinoline derivatives via Hantzsch reaction in water as a green solvent. In this sense, simple preparation of the catalyst from the commercially available materials, high catalytic activity, simple operation, short reaction times, high yields and use of green solvent can be regarded as some advantages of this protocol. In addition, it is worth mentioning that this nanocatalyst was easily recovered using external magnet and reused for several times without significant loss of its catalytic efficiency. Finally, the leaching, heterogeneity and stability of Fe3O4@Schiff-base-Cu were studied by hot filtration test and ICP technique. Graphic A green and novel Fe3O4@Schiff-base-Cu catalyst sucssesfully was prepared and characterized. This catalyst can be used for the Synthesis of polyhydroquinolines in water as the green solvent. This catalyst could be recovered easily and reused many times without important decrease in efficiency.