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 biim)(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 C–H⋯π 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. [ABSTRACT FROM AUTHOR]