Syntheses, crystal structures and luminescent properties of three metal coordination polymers based on aromatic carboxylic acids and 2-(pyridine-4-yl)-(1H)-benzoimidazole

Abstract

Three new metal coordination complexes, namely [Co(IPA)(4PBI)]·H2O (1), [Cd(IPA)(4PBI)(H2O)] (2) and [Cd(TPA)(4PBI)(H2O)] (3) [4PBI=2-(pyridine-4-yl)-(1H)-benzoimidazole, IPA=isophthalate and TPA=terephthalate], were obtained under hydrothermal conditions by reacting cobalt and cadmium salts with 4PBI and IPA or TPA. Complexes 1–3 were structurally characterized by X-ray single-crystal diffraction, EA, IR and PXRD. All of these complexes display low dimensional features with one-dimensional (1D) motifs. Complex 1 is a 1D tape-like structure containing bi-nuclear units, which is further extended into a 3D supramolecular architecture through intermolecular hydrogen bonds and stacking interactions. Complex 2 shows a 1D structural motif, which is further assembled into a 3D supramolecular architecture by hydrogen bonds and packing interactions. Complex 3 is also a 1D chain. Through intermolecular hydrogen bonds and π⋯π packing interactions, a 3D supramolecular network is also generated for 3. The luminescent properties of complexes 2 and 3 were investigated in the solid state at room temperature. Additionally, thermogravimetric analysis (TGA) of 1–3 has been discussed in details.