Synthesis, structures and the biological activity study on the metal complexes of 2-(4-aminophenyl)benzothiazole derivative

(2-(4-(Benzothiazole)phenyl)carbamoylmethyl)iminodiacetic acid (ZL-5) was synthesized and then its three metal complexes were prepared with structures determined by 1H NMR or X-ray. In all complexes, ZL-5 is deprotonated to generate the neutral complex unit and acts as a tetradentate ligand, providing iminodiacetic N atom and three O atoms to bond with metal ions. Meantime we studied on the interaction of complexes with DNA by ultraviolet spectrum and fluorescent spectrum. Also the cleavage abilities of the complexes on plasmid pBR 322 DNA were studied by gel electrophoresis. We deduce the Co(II) complex 1 with the largest planar structure has the strongest DNA binding ability mainly by the intercalation mode, while the Cu(II) complex 2 with the coordinated water cut the DNA most effectively. And in the oxidative cleavage process of all complexes, the hydroxyl radical is produced which can be captured by DMSO.

The emission intensity of CT DNA-bonded EB (DNA/EB = 10/1) when adding different concentrations of three complexes in 50 mM Tris–HCl buffer (pH 7.4) at room temperature on addition of complex 1 (●), complex 2 (○), complex 3 (▾).Figure optionsDownload as PowerPoint slideHighlights
► (2-(4-(Benzothiazole)phenyl)carbamoylmethyl)iminodiacetic acid (ZL-5) and its three metal complexes were synthesized.
► The complexes compete with the intercalative EB binding to DNA in a different degree which is coinciding with their solid structure.
► The complex 2 shows the highest cleavage ability which produces the OH radical in the oxidizing process.