Water-stable lanthanide-based metal-organic frameworks for rapid and sensitive detection of nitrobenzene derivatives

Two novel lanthanide metal-organic frameworks, namely {[Ln(2)(NSBPDC)(3)(H2O)(4)]center dot x(H2O)}(n) (Ln = Eu 1, Tb 2), have been facilely synthesized with 6-nitro-2,2'-sulfone-4,4'-dicarboxylic acid (H2NSBPDC). Structural analyses revealed that the two complexes are both three-dimensional (3D) non-interpenetrating networks based on infinite rod-shaped Ln(III) carboxylate SBUs and exhibit 1D channels decorated with functional groups. Fluorescence measurements show that complex 1 can serve as a fast and recyclable fluorescence sensor for nitroaromatics detection via a turn-off response with low detection limits. The fluorescence quenching of 1 for nitroaromatics is presumably due to the following two reasons: the photo-induced electronic transfer mechanism and the competitive adsorption mechanism.