Research of the influence of anions in complexes [CuPhen(Hpz)2X2] (X = CF3COO−, Otf−, Cl−) on the structure and bioactivity

Abstract

A series of copper(II) complexes with different anions of composition [CuPhen(Hpz)₂X₂] (Phen = 1,10-phenanthroline; Hpz = pyrazole; X = CF₃COO⁻ (1), Otf⁻ (2), Cl⁻ (3), Otf = CF₃SO₃) have been synthesized. The structures of all obtained complexes were determined by direct X-ray diffraction analysis. In complexes 1–3 the equatorial planes are occupied by N-donor ligands, while the axial positions belong to the anions of various acids. Crystal structures 1–3 are additionally stabilized by hydrogen bonds, the type of which depends on the nature of the anion. The stability of the complexes upon dissolution in 0.9% NaCl was confirmed by UV-vis spectroscopy. The study of the biological properties of 1–3 showed high antibacterial activity against the non-pathogenic strain of Mycolicibacterium smegmatis (MIC (minimum inhibiting concentration) = 8–10 nmol per disk). The cytotoxic effect of various concentrations of complexes 1–3 on human ovarian adenocarcinoma cells (SKOV3) and human dermal fibroblasts (HDF) was measured in vitro. All complexes exhibit high anticancer activity, exceeding the activity against healthy cells.