Two Highly Water-Stable Imidazole-Based Ln-MOFs for Sensing Fe3+,Cr2O72–/CrO42– in a Water Environment

Developing highly stable materials for harmful ion detection in a water environment is of much importance and challenging. Here, two three-dimensional porous structures (termed as Eu-MOF and Tb-MOF) were successfully constructed by the strategy of anchoring Eu3+/Tb3+ and rigid 1,2,4,5-benzenetetracarboxylic acid (H4BTEC) imidazole units (H3ICA) onto its frameworks. The obtained Eu-MOF and Tb-MOF display high water stability and fluorescence stability up to 30 days. Furthermore, luminescent studies reveal that Eu-MOF and Tb-MOF show rapid, recursive, and simultaneous sensing Fe3+ and Cr2O72–/CrO42– ions in water. In addition, the sensing function possesses remarkable cyclicity and selectivity even with the existence of other analogous ions.