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.