Synthesis, characterization and DNA interaction of imidazo(1,2-a)pyridine derivaties

In this work, imidazo(1,2-a)pyridinyl-8-benzimidazole and 2,2'-bis(imidazo[1,2-a]pyridin-8-yl)-3H,3'H-5,5'-bibenzo[d]imidazole synthesis, characterization and DNA interactions of ligands were studied. The ligand The characterization of the obtained ligands was carried out by FT-IR, 1H-NMR, 13C-NMR, ESI-MS analysis methods. DNA interactions of the complexes were studied by UV-Vis titration, fluorescence, viscosimetry, melting point change and agarose gel electrophoresis methods. UV-Vis titration results show that both compounds bind to DNA as groove binders. The binding constants are 3.5 × 104 M-1 and 1.5 × 105 M-1, respectively. Viscosity and melting point studies also support this result. According to the fluorescence studies, the compounds were found to be weak groove binders and L2 binds weaker than the Hoechst-33258 dye from the minor groove. In electrophoresis studies, both compounds failed to perform any breaks on DNA while no activators were present in the medium. However, the L2 compound neutralized the negative charge of DNA in high concentration and caused DNA to collapse on the gel. In the presence of peroxide, L2 has a higher DNAse activity than L1.