Synthesis of layered rare-earth hydroxide intercalated with benzoate ions

We report a new family of lanthanide-based inorganic-organic hybrid frameworks Y_1.9Eu_0.1(OH)₅[C₆H₅COO]· 2H₂O synthesized by homogeneous precipitation. The crystal structure obtained from powder X-ray diffraction data revealed that this material comprises two-dimensional cationic lanthanide hydroxide ([Ln₂(OH)₅(H₂O)]⁺∞ layers, which are cross-linked by benzoate ligands into a three-dimensional pillared framework. The single layered nanosheets were obtained in n-butanol after the supersonic treatment. The morphologies of the nanosheets were a hexagonal structure about 800 nm in size as determined by transmission electron microscopy, and the thickness of the nanosheets was about 1.8 nm measured by atomic force microscopy. The fluorescence intensity of the ⁵D₀-⁷F₂ transition increased nearly 3.8 times. The lifetime of the material increased to 0.43 ms compared with the lifetime of Eu³⁺ in an aqueous medium of 0.1 ms.