A Family of Hydrazone‐Based Nucleosides for Use in Metal‐Mediated Base Pairs

A new family of hydrazone‐based nucleosides for use in metal‐mediated base pairs was devised. The artificial nucleobases are derivatives of the papy ligand (papy = pyridinecarboxaldehyde‐2′‐pyridylhydrazone). By replacing the pendant pyridine moiety in papy by furan and thiophene, respectively, tridentate nucleosides with N, N, N‐, N, N, O‐ and N, N, S‐donor sites were obtained. As only a few transition metal complexes with pendant furan ligands have been reported, a model nucleobase for the N, N, O‐donor nucleoside was synthesized. The molecular structures of its Cu2+, Ni2+, and Co2+ complexes are reported. In all complexes, only weak M–O(furan) bonding is observed. The Co2+ complex displays a pentagonal bipyramidal coordination arrangement. In general, the structures of the metal complexes suggest that the respective nucleosides can be applied in metal‐mediated base pairs.