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

Abstract

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.