A Terbium‐Based MOF as Fluorescent Probe for Selective Sensing of Nitrobenzene and Fe³⁺

Abstract A three‐dimensional metal‐organic framework named as [Tb L (OH) 2 ](COOH) 3 ⋅ (solvent) x (Tb‐MOF), was successfully obtained by using Tb(NO 3 ) 3 ⋅ 6H 2 O and 1,1′,1′′‐(2,4,6‐trimethylbenzene‐1,3,5‐triyl)tris(methylene)‐tris(4‐carboxy‐pyridinium)tribromide (H 3 L Br 3 ) as raw materials. A series of fluorescence detection experiments demonstrate that Tb‐MOF shows a fluorescence quenching effect on NB. Moreover, Tb‐MOF also exhibits a very fast fluorescence quenching response to trace Fe 3+ ions, which is unaffected by the existence of other competitive metal cations. The linear curve between the fluorescence intensity of Tb‐MOF and the concentration of Fe 3+ was plotted by the fluorescence titration experiments data. The calculated LOD for Fe 3+ ions is 2.86×10 −6 M. Therefore, based on the characteristics of Tb‐MOF, it can be regarded as a luminescent sensor for detecting NB and Fe 3+ . We have also explored the quenching mechanism of Tb‐MOF as a fluorescent sensing material.