Syntheses, Crystal Structures and Photoluminescence of Three Complexes Based on 3,5-(3-Carboxybenzyloxy)benzoic Acid

Three stable coordination polymers (CPs) assembled by 3,5-(carboxybenzyloxy)-benzoic acid (H3L) and 1,10-phenanthroline (phen), namely, [Zn(HL)(phen)](n) (1), [Cd(HL)(phen)](n) (2) and [Co(HL)(phen)](n) (3), have been synthesized under hydrothermal conditions. Their structures have been determined by single-crystal X-ray diffraction analyses and further characterized by elemental analyses, infrared (IR) spectroscopy and powder X-ray diffraction (PXRD). Investigation on crystal structure indicates that complexes 1 similar to 3 exhibit similar architecture. In these complexes, metal ions coordinate with H3L and phen ligands, forming infinite 1D chains. Then the adjacent chains combine together through intramolecular hydrogen-bonding interactions, generating 2D supramolecular architectures. In addition, complexes 1 similar to 3 present excellent thermal stabilities and 1 and 2 exhibit strong luminescent emission bands at room temperature.