Design and DNA-binding of metallo-supramolecular cylinders conjugated to peptides

Di-nuclear metallo-supramolecular “cylinders”, based on bis-pyridylimine ligands, are end-functionalised with short peptides. The design and synthesis of one tetra-cationic triple-stranded (iron(II)) and three di-cationic double-stranded (copper(I) or silver(I)) cylinder–peptide conjugates are described. DNA-binding experiments, using circular and linear dichroism spectroscopies, confirm the binding and indicate that the iron(II) complexes cause DNA to bend or coil. Artificial nuclease activity by the copper(I) complexes is demonstrated by gel electrophoresis studies.