Amino-Functionalized Single-Lanthanide Metal-Organic Framework as a Ratiometric Fluorescent Sensor for Quantitative Visual Detection of Fluoride Ions.

Excessive content of fluoride ions (F - ) in water will lead to water pollution and endanger human health, so the research on the method of low-cost, rapid, and efficient detection of F - is of particular significance. In this work, an amino-functionalized ligand with an appropriate triplet energy excited state, 2'-amino-[1,1':4',1″-terphenyl]-3,3″,5,5″-tetracarboxylic acid (H 4 TPTC-NH 2 ), was selected to construct a luminescent single-lanthanide metal-organic framework, EuTPTC-NH 2 , with uncoordinated amino groups for the detection of F - . Based on host-guest interactions, that is, hydrogen bonds formed between the free amino groups and F - ions, EuTPTC-NH 2 was developed as a ratiometric fluorescence probe for F - detection with good anti-interference ability, low detection limit, high water stability, and selectivity. It was found that EuTPTC-NH 2 has an excellent linear response to F - in the concentration range of 0-80 μM with high sensitivity and a low detection limit of 11.26 μM. A hydrogel membrane based on the combination of EuTPTC-NH 2 and agarose was also prepared for the quantitative visual detection of F - in water.