Extremely stable europium-organic framework for luminescent sensing of Cr2O72- and Fe3+ in aqueous systems

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 (H2LCl2), 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 Cr2O72- and Fe3+.