Coordination polymers constructed from an asymmetric dicarboxylate and N-donors: preparation, characterization, and properties

Two new coordination polymers with an asymmetric dicarboxylate and 4,4'-bipyridine ligand, {[Co(bpy)(H2O)(4)]center dot(cpa)center dot 0.5H(2)O}(n) (1) and {[Ag(cpa)(bpy)][Ag(bpy)]center dot 4H(2)O}(n) (2) (H(2)cpa - 4-(2-carboxyethyl)benzoic acid, bpy = 4,4'-bipyridine), have been hydrothermally synthesized and characterized by elemental analysis, FT-IR spectroscopy, and single-crystal X-ray diffraction. Compound 1 displays a linear chain with guest molecule (cpa)(2-) ions existing in the structure. Compound 2 contains two independent units, [Ag(cpa)(bpy)](-) (A) and [Ag(bpy)](+) (B), which form a 1-D+1-D structure. A shows a 1-D chain structure bearing hooks formed by the carboxylates and organized into a tubular structure by hydrogen-bonding interactions. B has linear chains formed from Ag+ and bpy. The A and B chains co-crystallize with waters of crystallization to provide two linear [Ag(bpy)](+) chains embedded in the tubular structure formed by A via pi...pi stacking contacts. In 1 and 2, hydrogen-bonding and pi...pi stacking interactions connect the discrete 1-D chains into 3-D supramolecular structures. The fluorescent properties, TG analysis, and X-ray powder diffraction patterns for 1 and 2 were also measured.