Highly chemical and thermally stable lanthanide coordination polymers for luminescent probe and white light emitting diodes
A series of isomorphic lanthanide coordination polymers with 2,6-dimethylpyridine-3,5-dicarboxylic acid (H2mpda), formulated as [Ln(Hmpda)3(H2mpda)] [Ln = Tb (1), Eu (2), Gd (3) and Ln = mixed lanthanide (4)] have been synthesized and structurally characterized. Single-crystal X-ray diffraction reveals that they are isomorphic and each displays a 1D chain-based structure, which can be expanded into a 3D-supramolecular architecture by the hydrogen bond interactions. In addition, they are thermally stable up to 350°C and unusually chemical stability in a wide pH range of 2-13, which were confirmed by the variable temperature XRD and pH dependent XRD. Meanwhile, the luminescent properties of compounds 1-4 are investigated, of these compound 1 acts as the luminescent probe for the sensing of temperature and pH, and compound 4 shows the white light emission. Moreover, compounds 1, 2 and 4 were encapsulated into the LED devices, compound 4 exhibited the warm white light emission with excellent color rendering index (CRI) and correlated color temperature (CCT).