Europium Pyrimidine-4,6-dicarboxylate Framework with a Single-Crystal-to-Single-Crystal Transition and a Reversible Dehydration/Rehydration Process

In this paper, a novel three-dimensional (3D) porous lanthanide–organic framework, Eu2(μ4-pmdc)2(OH)2·3H2O (1), which is stable up to 400 °C, has been hydrothermally synthesized and characterized. It shows intriguing single-crystal-to-single-crystal transformation and reversible dehydration/rehydration phenomenon upon removal and rebinding of the lattice water molecules, which is supported by single-crystal X-ray diffraction, powder X-ray diffraction, and photoluminescence data.