Metallo-supramolecular Polymers: Versatile DNA Binding and Their Cytotoxicity

Metallo-supramolecular polymers (RuL1, RuL2, RuL3, FeL3, and FeL4) prepared by complexation of bis(terpyridine) derivatives with Ru2+ or Fe2+ ions with octahedral coordination structures showed high binding ability to several DNAs (calf thymus DNA, herring sperm DNA, [poly(dA-dT)]2, and [poly(dG-dC)]2), which were revealed by UV–Vis absorption titration experiments. The electrostatic interactions between the metal cations of the polymers and phosphate anions of DNA led to formation of conjugate structure. The binding constant observed reached 3.7 × 107 M−1, which is the highest among values reported for metal complexes to date. Based on a long strand structure of the polymer, groove binding is most possible binding mode. Cell viability experiments showed that RuL3 and FeL3 displayed highly statistical significance (**p<0.01) to human non small cell lung cancer cell lines (NCI-H460).