Coordination polymers of the bis(imidazole) ligand modulated by dicarboxylate ligands: From 2D layer to 3D framework

Three new coordination polymers, [Zn(H(2)biim)(pzdc)](n) (1), [Cd(H(2)bilm)(Pzdc)](n) (2) and [Cd(H(2)biim)(0.5)(ip-OH)](n) (3) (H(2)biim = 2,2'-biimidazolate, H(2)pzdc = 2,3-pyrazinedicarboxylic acid, H(2)ip-OH = 5-hydroxylisophthalic acid), have been hydrothermally synthesized and characterized by elemental analysis, infrared spectra and X-ray single-crystal diffraction. Complexes 1 and 2 are isostructural and display two-dimensional (2D) undulated layers with 3-connected (4.8(2)) topologies, which are further extended into three-dimensional (3D) supramolecular structures through hydrogen-bonding and CH. H center dot center dot center dot pi interactions. Complex 3 is a relatively rare 3D compound, featuring a binodal (4,5)-connected (4(4).6(2))(4(4).6(6)) topology. A comparison of all the complexes demonstrates that the structural characteristics of the dicarboxylate ligands play a great role in the modulation of the coordination structures. Moreover, their luminescent properties and thermal stabilities were also investigated. (C) 2015 Elsevier Ltd. All rights reserved.