Investigation of selective metal-complexation in terpyridine and phenanthroline based polymeric systems

In the current study, we present the synthesis of a polymeric template featuring two adjoining ligand moieties (i.e. terpyridine and phenanthroline), which are capable to selectively bind ligand counterparts by the simultaneous formation of heteroleptic complexes. This represents the first example for the incorporation of the specific heteroleptic [Cu(tpy)(phen)]2+ binding motif, based on unmodified ligands in a polymeric architecture. The polymeric template is intensively investigated by isothermal titration calorimetry to characterize the complexation formation, while electron paramagnetic resonance spectroscopy is applied to study structural geometries as well as electronic properties of the polymeric supramolecular structure in comparison to corresponding model complexes. The utilized methods provide strong evidence for a highly specific heteroleptic complex formation at the polymer ligand moieties.