Ni2+ and Cu2+ complexes of a phenanthroline-based ligand bind to G-quadruplexes at non-overlapping sites.

Transition metal complexes allow fine tuning of DNA binding affinity and selectivity. Here we report on the nucleic acid recognition properties of a phenanthroline-based ligand coordinated to Ni2+ or Cu2+. The resulting complexes clearly bind to telomeric G-quadruplexes at different sites according to the nature of the bound metal ion.