Synthesis, crystal structure and luminescence of zinc(II) coordination polymers based on a flexible bifunctional terpyridyl carboxylic ligand

Abstract

The new ligand 4′-(4-carboxy-methyleneoxyphenyl)-2,2′:6′,2″-terpyridine (HL) and its five zinc coordination polymers, [Zn(L)Cl]2n·nH2O (1), [Zn(L)(bdc)0.5]n·2nH2O (2), [Zn(L)(adip)0.5]n·3nH2O (3), [Zn(L)(suc)0.5]n (4) and [Zn(L)(fum)0.5]n (5), were synthesised and characterised. Single crystal X-ray diffraction analyses revealed that compounds 1–3 are one-dimensional (1D) chains. Compounds 4 and 5 have similar structures which demonstrate triple-stranded helical chains and a 3-fold 2D interpenetrated network. The plentiful hydrogen-bonding sites and π–π interactions originating from the pyridyl rings of the ligand HL greatly contribute to the structures in complexes 1–5, exhibiting an intriguing ability in supramolecular assembly. In addition, the thermal stabilities and photoluminescence properties of complexes 1–5 were also studied in the solid state.