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

Abstract

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 (H 3 TNB) with electron-donor triphenylamine (TPA), the highly porous pillared-layer compound 1 [Zn 3 (TPPE) 1/2 (TNB) 2 ](4DMA·7H 2 O) 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 [Zn 7 (TPPE) 2 (SO 4 2– ) 7 ](DMF·H 2 O) exhibits the clear “turn-off” quenching responses for Cr 2 O 7 2– in aqueous phase with high selectivity and sensitivity. Meanwhile, the fluorescent properties of compound 3 [Zn 2 (TPPE) 3/2 (NO 3 – )(OH – )(H 2 O)](DMF·2H 2 O) were also investigated. Thus, these MOF materials could serve as the promising platform for luminescent sensing.