Dehydration and Rehydration Processes in Microporous Rare-Earth Dicarboxylates: A Study by Thermogravimetry, Thermodiffractometry and Optical Spectroscopy

The recently discovered microporous materials, [Ln(H2O)]2 [O2C(CH2)2CO2]3·H2O and [Ln2(H2O)]2[O2C(CH2)3CO2]3· 4H2O (Ln=trivalent rare-earth ion), exhibit a three-dimensional organic–inorganic network with channels containing weakly bonded water molecules. The ability of these compounds to reversibly adsorb and desorb these water molecules in the temperature range 25–100°C has been confirmed using thermo-gravimetry and thermodiffractometry. In addition, the influence of adsorbed water on the lifetime of the 5D0 state of Eu3+ has been studied by optical spectroscopy.