Synthesis, crystal structure, DNA-binding properties and antioxidant activity of zinc(II) complexes based on the V-shaped bis(2-benzimidazol-2-ylmethyl)benzylamine ligand and its derivative

• Two ligands and their Zn(II) complexes have been synthesized and characterized.
• The interaction of ligands and Zn(II) complexes with DNA have been investigated.
• The antioxidant activity of the Zn(II) complexes were investigated.

Two V-shaped ligands, bis(2-benzimidazol-2-ylmethyl)benzylamine (L1) and its derivative bis(N-allylbenzimidazol-2-ylmethyl)benzylamine (L2) have been prepared. Reaction of two shaped-specific designed ligands with Zn(pic)2 (pic = picrate) afforded two novel complexes, namely, [ZnL12](pic)2·2MeCN·Et2O 1, and [ZnL22](pic)22. The ligands and Zn(II) complexes were characterized by elemental analysis, UV–Vis, IR spectroscopy. Single crystal X-ray diffraction revealed that two Zn(II) complexes have similar distorted octahedral coordination geometry, except that the degree of distortion is different. In order to explore the relationship between the structure and biological properties, the DNA-binding properties have been investigated by viscosity measurement, electronic absorption and fluorescence titration. The results suggested that the ligands and Zn(II) complexes bind to DNA via intercalative binding mode, and their binding affinity for DNA are also different. Moreover, two Zn(II) complexes also exhibited potential antioxidant properties in vitro studies, and the complex 1 reveal more effective than complex 2.

Two zinc(II) complexes based on the V-shape bis(2-benzimidazol-2-ylmethyl)benzylamine ligand and its derivative have been synthesized and characterized. The ligands and Zn(II) complexes bind to DNA in an intercalation mode and the Zn(II) complex has good antioxidant activities.Figure optionsDownload as PowerPoint slide