Synthesis and characterization of the ligand based on benzoxazole and its transition metal complexes: DNA-binding and antitumor activity.

A new ligand 2-((2-((benzo[d]oxazol-2-yl)methoxy)phenoxy)methyl)benzoxazole (L) and its four transition metal complexes M(NO(3))(2)L (M=Cu, Co, Ni, Zn), have been synthesized and investigated. The single crystal structures of the complexes show that all of them have similar molecular structure and the ligand exhibits good coplanarity after coordination with the metal ions. Further investigation of DNA binding indicates that both the ligand L and the complexes can bond to DNA by intercalation mode, and the latter possesses much stronger binding affinity. Antitumor activity of these compounds tested on the four cancer cell lines, follows the order: Cu-L>Ni-L approximately Co-L>Zn-L>>L, which are thought to be related with their DNA-binding affinity.