Tetraphenylethylene Immobilized Metal–Organic Frameworks: Highly Sensitive Fluorescent Sensor for the Detection of Cr₂O₇^2– and Nitroaromatic Explosives

From the perspective of the chromophore, 1,1,2,2-tetrakis(4-(pyridin-4-yl)phenyl)ethane (TPPE) with the π-electron-rich tetraphenylethylene (TPE) and aggregation induced emission feature is selected as functional ligand to construct the fluorescent metal–organic frameworks. Three luminescent MOFs (1–3) have been successfully synthesized. Through combining 4,4′,4″-nitrilotrisbenzoic acid (H3TNB) with electron-donor triphenylamine (TPA), the highly porous pillared-layer compound 1 [Zn3(TPPE)1/2(TNB)2](4DMA·7H2O) was synthesized; interestingly, this MOF sensor film realizes the fast detection for nitrobenzene compounds with a response time of less than 3 min as well as good recyclability. Compound 2 [Zn7(TPPE)2(SO42–)7](DMF·H2O) exhibits the clear “turn-off” quenching responses for Cr2O72– in aqueous phase with high selectivity and sensitivity. Meanwhile, the fluorescent properties of compound 3 [Zn2(TPPE)3/2(NO3–)(OH–)(H2O)](DMF·2H2O) were also investigated. Thus, these MOF materials could serve as the promising platform for luminescent sensing.