VGV-1

This work addresses the detection of nitroaromatic compounds (NACs) and antibiotics in water by developing two isomeric fluorescent metal–organic framework (MOFs) Cd-1 and Cd-2, with the formula [Cd2(Tipe)(ABD)2]·solvent (Tipe = 1,1,2,2-tetrakis(4-(1-imidazolyl)phenyl)ethylene, H2ABD = 4,4′-azodibenzoic acid). By modulating the reaction solvent, two interpenetrated isomeric MOFs with distinct space groups and fluorescence properties were obtained. Interestingly, Cd-1 and Cd-2 exhibit high selectivity and rapid response (<10 s) toward 2,4,6-trinitrophenol (TNP) and nitrofurazone (NFZ) with distinct response behaviors. Namely, Cd-1 shows fluorescence quenching at both 423 and 485 nm, whereas Cd-2 exhibits quenching only at 423 nm but remains unchanged at 485 nm, implying a ratiometric fluorescence sensor (I423/I485). Both Cd-1 and Cd-2 possess low detection limits (0.32 and 0.24 μM for TNP and 0.34 and 0.15 μM for NFZ), strong anti-interference ability, good reusability, and structural stability. Spectroscopic overlapping and fluorescence lifetime shortening imply a dynamic quenching mechanism. X-ray photoelectron spectroscopy (XPS) analysis further suggests electron transfer from the MOF skeleton to analytes of TNP/NFZ. This study provides an example of solvent-regulated interpenetration isomerism in MOFs, reveals its modulatory role in fluorescence response behaviors, and offers new insights for designing ratiometric fluorescence sensors.

A series of o-carborane-based aza-oxa-triazole macrocycles (No, D₂, D₄) were synthesized via Cu(I)-catalyzed azide-alkyne cycloaddition (CuAAC). Simply by substituting the azide diethanolamine precursor, two dansyl-modified macrocycles (D₂ and D₄) with dual-state emission (DSE) were readily obtained. The incorporation of the dansyl moiety significantly enhanced the luminescence, resulting in higher quantum yields and longer fluorescence lifetimes. Additionally, the macrocycles exhibit unique aggregation-induced emission (AIE) properties and macrocycles D₂ and D₄ simultaneously exhibit aggregation-induced quenching (ACQ) and AIE characteristics. Furthermore, these macrocycles function as selective fluorescent sensors for nitroaromatic compounds, particularly demonstrating excellent specificity and anti-interference ability toward 2,4,6-trinitrophenol (TNP) with a notable fluorescence quenching response. Macrocycle D₂ achieved a remarkably low detection limit of 7 × 10^-8 M for TNP in THF.