Synthesis, characterization, and biological activity of cobalt(II), nickel(II), copper(II), and zinc(II) complexes of secnidazole

Abstract Thirteen coordination compounds of Co II , Ni II , Cu II , and Zn II with the biologically active ligand secnidazole were designed, synthesized, and fully characterized. Using UV–Vis–NIR spectroscopy, elemental analyses, mass spectrometry, molar conductivity, magnetic susceptibility, thermogravimetry, and X-ray diffraction methods, it was determined that the compounds adopt diverse geometries and coordination numbers that range from 4 to 6 as well as different nuclearities. These structural features depend on the choice of the labile groups in the coordination sphere such as chlorides and bromides (mononuclear/tetrahedral), nitrates (mononuclear/tetrahedral or octahedral), and acetates (dinuclear bridged/squared-base pyramid). The ability of the complexes to inhibit carcinoma cells growth was assessed by determining their IC 50 values (half-maximum inhibitory concentration) in three different human carcinoma cell lines: HeLa (cervix-uterine), PC3 (prostate), and HCT-15 (colon). It was found that the most active complexes display IC 50 values in the range of 160 – 180 μM. HeLa was found to be the most sensitive cell line towards the treatment, followed by PC3, and HCT-15. The complexes were tested for antimicrobial activity and proved to be non-active against Staphylococcus aureus , Salmonella typhi , Escherichia coli , Micrococcus luteus , and Pseudomonas aeruginosa .