Synthesis, crystal structures and properties of three metal–organic supramolecular architectures based on mixed organic ligands

Three metal–organic supramolecular architectures, Co(H2O)2(H2THFTCA)(4,4′-bpy)·1/2H2O (1), Zn(H2THFTCA)(phen)·H2O (2) and Cd3(H2O)2(HTHFTCA)2(4,4′-bpy)2·4H2O (3), constructed from mixed organic ligands of tetrahydrofuran-2,3,4,5-tetracarboxylic acid (H4THFTCA) and 4,4′-bipyridine or 1,10-phenanthroline, have been synthesized and characterized. Complex 1 crystallizes in triclinic space group P-1 and has a discrete mononuclear structure. The multiple hydrogen bonding interactions connect 1 into a three-dimensional NaCl-like supramolecular architecture. Complex 2 crystallizes in monoclinic space groupP21/n and possesses a one-dimensional helical chain structure. The π⋯π stacking between the chains further connects 2 into a two-dimensional layer architecture. Complex 3 crystallizes in monoclinic space groupC2/c and has a rare three-dimensional 4,6-connected net. The THFTCA ligand connects the cadmium ions to form a two-dimensional layer, which is further connected by pillared 4,4′-bpy ligands to form the three-dimensional porous framework. The thermal stabilities of 1, 2, 3 and the photoluminescence properties of 2 and 3 have been studied.