Synthesis and magnetic and cytotoxic properties of copper(ii) halide complexes with 1,2,4-triazolo[1,5-a] benzimidazoles

Abstract

Coordination compounds based on copper(II) halides with 4H-1,2,4-triazolo[1,5-a]benzimidazole (L¹), 3-methyl-1,2,4-triazolo[1,5-a]benzimidazole (L²), and 4-methyl-1,2,4-triazolo[1,5-a]benzimidazole (L³) with the compositions [Cu(L¹)₂(Hal)₂]·nH₂O (Hal = Cl⁻, n = 0.5 (I) Br⁻, n = 1 (II)); [Cu(L²)₂Cl₂] (III), [Cu(L³)₂Cl₂] (IV) and [Cu(L³)₂Br₂(H₂O)]·2H₂O (V) were synthesized. The compounds were characterized using X-ray diffraction, UV-Vis spectroscopy (diffuse reflectance spectra), infrared spectroscopy, and static magnetic susceptibility measurements. By means of X-ray diffraction structural analysis, crystal structures were determined for the [Cu(L³)₂(Hal)₂(H₂O)]·2H₂O complexes, where Hal = Cl⁻ (IVa) or Br⁻ (V). Cytotoxic effects of the complexes and ligands on the cell line Hep-2 were then studied, and we found that the copper(II) complex with ligands L¹–L³ leads to a considerable enhancement of cytotoxicity.