Extremely stable europium-organic framework for luminescent sensing of Cr2O72− and Fe3+ in aqueous systemsElectronic supplementary information (ESI) available: The experimental data, crystallographic data, topology structure, additional luminescence spectra, IR and PXRD data before and after sensing experiment, and UV-Vis data. CCDC 1828085, 1843899 and 1843900 for Ln-MOF. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c8dt02313a

Three novel 3D lanthanide-organic frameworks, namely [Ln 2 L(1,3-bdc) 3 ]·5H 2 O (Ln: Eu, Sm and Dy), with a 4 12 ·6 3 topology based on a zwitterionic ligand, 4-bis(4-carboxylatopyridinium-1-methylene)benzene dichloride (H 2 LCl 2 ), and 1,3-benzene dicarboxylic acid (1,3-H 2 bdc) have been synthesized hydrothermally. Notably, the Ln-MOFs are extremely stable in an aqueous system and are capable of resisting acids or bases over a wide pH range from 3 to 11. Meanwhile, an Eu-MOF is further proven to be a promising dual sensor in an aqueous system toward Cr 2 O 7 2− and Fe 3+ . A novel Eu-MOF which is extremely stable in an aqueous system over a wide pH range is reported as a dual functional Cr 2 O 7 2− and Fe 3+ sensor in aqueous environments.