Synthesis, thermal behaviour and some properties of CuII complexes with N,O-donor Schiff bases

Abstract

The complexes of N2O2-, N2O3- and N2O5-donors Schiff bases with CuII ions in the methanol solution have been synthesized. They were characterized by elemental analysis, X-ray crystallographic techniques, spectroscopic (UV–Vis, IR) and thermal (TG, TG-FTIR) methods. The catalytic activity of the prepared complexes for the hydrogen peroxide-assisted degradation of methylene blue (MB) as the model compound in water was also investigated. The complexes were obtained as crystalline solids. Depending on the Schiff bases and the molar ratio of CuII:ligand used in the synthesis, they can form monomeric or dimeric structures. The coordination environment around the metal centre in both solution and solid states is a slightly distorted square-planar. The values of magnetic moments determined at room temperature show the existence of antiferromagnetic interactions. The complexes are stable at ambient temperature. After heating, at first solvates lose solvent molecules; after that, an organic part undergoes gradual defragmentation and combustion. Degradation efficiency of MB in the presence of complexes was found to be 68.18–97.47%. A tentative mechanism involving HO· radical as an oxidant for degradation of MB was proposed.