Copper-hydroxyacetophenone thiosemicarbazone complex on silica-coated magnetite nanoparticles as an efficient catalyst for three-component synthesis of 1,4-disubstituted 1,2,3-triazoles

A novel magnetically separable catalyst, the copper-hydroxyacetophenone thiosemicarbazone complex immobilized on silica-coated magnetite nanoparticles (Fe3O4@SiO2-HAT-Cu(I)), has been synthesized and characterized. The characterization included various techniques such as X-ray diffraction spectroscopy (XRD), energy dispersive X-ray spectroscopy (EDX), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), dynamic laser scattering (DLS), thermogravimetric analysis (TGA), vibrating sample magnetometer (VSM), atomic absorption spectroscopy (AAS), inductively coupled plasma-optical emission spectrometry (ICP-OES), and Fourier-transform infrared spectroscopy (FT-IR). The catalytic activity of Fe3O4@SiO2-HAT-Cu(I) was evaluated in a green aqueous mediated three-component synthesis of 1,2,3-triazles. The catalyst efficiently facilitated the 'Click' Huisgen cycloaddition reaction between alkynes, sodium azide, alkyl bromides and/or epoxides in water/THF at 70 C-degrees, resulting in good to excellent yields of 1,4-disubstituted 1,2,3-triazle derivatives. Fe3O4@SiO2-HAT-Cu(I) is a new, low-cost, and magnetically separable heterogeneous catalyst that can be easily prepared and reused for multiple reaction runs without significant loss of catalytic activity.