Crystal structures, DNA interaction and growth inhibitory activities of the cobalt(II) and nickel(II) complexes of 2-aminothiazole with demethylcantharate

Two new mixed-ligand complexes [M(atz)(DCA)(H2O)2]·2H2O, (M = Co(II), Ni(II); atz = 2-aminothiazole, C3H4N2S; DCA2− = demethylcantharate, 7-oxabicyclo[2,2,1]heptane-2,3-dicarboxylate, C8H8O5) were prepared and characterized by elemental analysis, infrared spectra and thermogravimetric analysis. The structures of the complexes were determined by X-ray diffraction. The crystals have empirical formulas CoC11H20N2O9S (1) and NiC11H20N2O9S (2), respectively. Complexes 1 and 2 are monoclinic systems with space group P21/m. The structures of the complexes assume severely distorted octahedral geometries. The DNA binding properties of the complexes were investigated by fluorescence quenching studies and viscosity measurements. For the complexes quenching the fluorescence of EB–DNA system, Stern–Volmer quenching constant Ksq values are 0.58 (1) and 1.38 (2), and the interaction modes between the complexes and DNA are partial intercalation. They have moderate activities against human hepatoma cell lines (SMMC7721) and human gastric carcinoma cell lines (MGC80-3) in vitro.