Synthesis and Tetraphenylethylene-Based Aggregation-Induced Emission Probe for Rapid Detection of Nitroaromatic Compounds in Aqueous Media

Abstract

Tetraphenylethylene (TPE) can be used to construct fluorescent probes with typical aggregation-induced emission (AIE) behavior for next-generation sensing applications. McMurry coupling and Suzuki cross coupling strategies provided the desired sensor thiophene-substituted tetraphenylethylene (THTPE). The synthesized TPE analogues were characterized by NMR spectroscopy and mass spectrometry. Maximum AIE of THTPE was observed in 90% water (H₂O/THF) content due to extensive formation of aggregates. The AIE properties of THTPE have been utilized for facile detection of nitroaromatic compounds (NACs) (1.0 nM) through a fluorescence quenching mechanism. A paper strip adsorbed with the AIE-based THTPE fluorophore is developed for rapid and convenient detection of NAC-based analytes. Further, interaction of THTPE with analytes is also studied via Gaussian software at the DFT/B3LYP/6-31G(d) level of theory. Interaction energy, frontier molecular orbitals (FMOs), and non-covalent interaction (NCI) analyses are studied by using the same method. Computational results revealed that nitrobenzene (NB) has the strongest interaction while 1,3-dinitrobenzene (DNB) exhibits the least interaction with the sensor molecule. These computational results clearly demonstrate good agreement with experimental data.