A new 3D Cd(II) metal–organic framework with discrete (H2O)6 clusters based on flexible cyclohexane-1,2,4,5-tetracarboxylic acid ligand

• A new 3D Cd(II)-MOF with flexible CTA and bpp ligands is obtained.
• The CTA ligands adopt a single conformation, while the bpp ligands feature two types of conformations.
• A cyclic (H2O)6 cluster fills in the 1D channel of the framework.

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.

A 3D Cd(II) mixed-ligand MOF containing cyclohexane-1,2,4,5-tetracarboxylic acid and 1,3-bis(4-pyridyl)propane has been synthesized and structurally characterized. Six-molecule water clusters fill the 1D channels of the structural framework.Figure optionsDownload as PowerPoint slide