Disclosing the Properties of a New Ce(III)-Based MOF: Ce₂(NDC)₃(DMF)₂

The new Ce­(III) based metal–organic framework Ce₂(NDC)₃(DMF)₂, containing the simple ditopic linker napthalenedicarboxylate (NDC^2–), has been synthesized under solvothermal reaction conditions with high purity and yield. Its crystal structure was determined with single-crystal X-ray diffraction (SC-XRD) techniques and further confirmed by Ce K-edge X-ray absorption spectroscopy (XAS). Upon thermal activation the compound revealed a phase transformation at about 300 °C involving the removal of the solvent molecules, which has been investigated in detail by thermogravimetric analysis, variable temperature powder X-ray diffraction, EXAFS and Fourier-transform infrared spectroscopy techniques. The crystal structure of the compound after desolvation (Ce₂(NDC)₃) becomes severely disordered, but a synergic use of both SC-XRD and Ce K-edge EXAFS allowed us to reveal its crystal structure. Porosity and adsorption properties were studied by the means of volumetric adsorption measurements. Ce₂(NDC)₃ is porous toward carbon dioxide at −78 °C, resulting in a surface area of about 200 m²/g. CO₂ uptake at 1 bar and 25 °C is about 4% by weight.