Thermal and chemical stability of europium(III) and terbium(III) coordination polymers with 4,4′-stilbenedicarboxylic acid: synthesis, structural transformations and sorption properties

Polycrystalline coordination polymers based on 4,4′-stilbenedicarboxylic acid (H 2 SDC) and selected lanthanide ions were synthesized via a conventional precipitation method in aqueous media, in accordance with the principles of green chemistry. The coordination compounds (Eu 2 SDC 3 ·5H 2 O and Tb 2 SDC 3 ·5.5H 2 O) were characterized by elemental analysis, powder X-ray diffraction (PXRD), ATR-FTIR spectroscopy, TG-DSC thermal analysis in air, nitrogen sorption measurements at −196 °C, and scanning electron microscopy (SEM). The influence of water, acidic (HCl), basic (NaOH), and hydrothermal conditions, as well as the dehydration process, on their structures and stability was investigated. The results revealed structural changes upon exposure to water and a partial loss of crystallinity due to the removal of solvent molecules. Acidic and basic environments led to degradation of the coordination polymers. As porous materials, their sorption capacities toward organic dyes were also evaluated, demonstrating their potential in environmental remediation. Additionally, corresponding lanthanide oxides were obtained via thermal decomposition of the parent complexes, which acted as structure directing agents.