Novel "Turn-On" Fluorescent Probe for Highly Selectively Sensing Fluoride in Aqueous Solution Based on Tb3+-Functionalized Metal-Organic Frameworks.

A Zr-based metal-organic framework (Zr-MOF) which has free carbonyl groups is synthesized successfully through mix-ligand strategy. Subsequently, Tb3+ is encapsulated into a Zr-MOF by postcoordinated modification. The Tb3+@Zr-MOF exhibits the characteristic emission of Tb3+ because of efficient sensitization through antenna effects. The Tb3+@Zr-MOF is further developed as a novel "turn-on" fluorescent probe to detect fluoride ions in aqueous solution. The results show that Tb3+@Zr-MOF exhibits excellent selectivity, high stability, low detection limits, and good anti-interference for sensitizing fluoride ions. In addition, the possible sensing mechanism that the induced luminescence properties may be attributed to Lewis acid-base interactions is discussed.