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

Abstract Two new mixed-ligand complexes [M(atz)(DCA)(H 2 O) 2 ]·2H 2 O, (M = Co(II), Ni(II); atz = 2-aminothiazole, C 3 H 4 N 2 S; DCA 2−  = demethylcantharate, 7-oxabicyclo[2,2,1]heptane-2,3-dicarboxylate, C 8 H 8 O 5 ) 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 CoC 11 H 20 N 2 O 9 S ( 1 ) and NiC 11 H 20 N 2 O 9 S ( 2 ), respectively. Complexes 1 and 2 are monoclinic systems with space group P 2 1 / 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 K sq 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.