Linear bilateral extended 2,2′:6′,2"-terpyridine ligands, their coordination complexes and heterometallic supramolecular networks

Octahedral metal complexes of tridentate 2,2':6',2"-terpyridine (terpy) fused with five-membered furan rings mimic the topology of tetrahedral metal complexes of bidentate 5,5'-functionalized 2,2'-bipyridine (bipy). Herein, we report the robust synthesis of 2,6-bis(2-substituted-furo[2,3-c]pyridine-5-yl)pyridine based ligands to access a series of linear bilateral extended terpy derivatives. This molecular design of alternating five-and six-membered rings has been applied to extend the applicability of terpy as a building block in supramolecular chemistry. The complexation of 2,6-bis(2-substituted-furo[2,3-c] pyridine-5-yl) pyridine derivatives with metal ions preferring octahedral geometry (Fe2+, Ru2+, and Zn2+) gives molecular "crossings" and "corners". Such design elements, functionalized with 4-pyridyl groups, allowed the construction of 3D and 2D heterometallic supramolecular networks containing Fe2+, Ag+ or Fe2+, Cu+ metal centers.