A new 3D Cd(II) metal–organic framework with discrete (H 2 O) 6 clusters based on flexible cyclohexane-1,2,4,5-tetracarboxylic acid ligand

A 3D metal–organic framework (MOF), {[Cd2(CTA)(bpp)2(H2O)2] (H2O)3}n (1) (H4CTA=cyclohexane-1,2,4,5-tetracarboxylic acid, bpp=1,3-bis(4-pyridyl)propane), has been synthesized and structurally characterized by elemental analysis, IR and powder X-ray diffraction. Single-crystal X-ray measurement reveals that the complex presents three-dimensional frameworks with 1D channels which are filled by unique (H2O)6 clusters. Noteworthily, the H4CTA ligands keep exclusive conformation, where the carboxyl groups adopt different coordination modes, and the bpp ligands perform two different conformations. Thermogravimetric analysis demonstrates that 1 features favorable thermal stability. Photoluminescence property of 1 is investigated in the solid state at room temperature as well.