Preparation of CuO nanoparticles by thermal decomposition of double-helical dinuclear copper(II) Schiff-base complexes

In this paper, two double helical dinuclear copper(II) complexes of bis-N,O-bidentate Schiff base ligands bis(3-methoxy-N-salicylidene-4,4'-diaminodiphenyl)sulfone (L1) and bis(5-bromo-N-salicylidene-4,4'-diaminodiphenyl)sulfone (L2) were prepared and characterized by elemental analyses (CHN), as well as thermal analysis. Elemental analyses (CHN) suggested that the reaction between ligands and copper salt has been occurred in 1:1 molar ratio. In these complexes the Schiff base ligands behaves as an anionic and bis-bidentate chelate and is coordinated to the copper(II) ion via two phenolic oxygen and two iminic nitrogen atoms. In these double helical dinuclear complexes, each copper(II) center has a pseudo-tetrahedral coordination sphere two-wrapped ligands. Thermal analysis of ligands and their complexes were studied in the range of room temperature to 750 °C with a heating rate of 10 °C min-1. TG plots show that the ligands and their complexes are thermally decomposed via 2 and 3 thermal steps, respectively. In addition, the complexes thermally decomposed in air at 520 °C for 3 h. The obtained solids characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD) and transmission electron microscopy (TEM). The X-ray pattern result shows that the CuO nanoparticles are pure and single phase. The TEM result shows the as prepared CuO nanoparticles were very small and similar shape with particle size about