A phenanthridine-based fluorescent sensor for selective ratiometric detection of BF3 with AIE properties and applications in environmental monitoring

Abstract

In this work, we report the synthesis of 5-(4-(pyridine-4-yl)phenyl)-7,8,13,14-tetrahydrodibenzo[a, i]phenanthridine (SP23), a phenanthridine-based chemosensor, by applying the Mannich reaction process. The starting components for this reaction were 2-tetralone, aromatic aldehyde, and ammonium acetate. Several spectroscopic investigations including 1H NMR, and HRMS were used to confirm the synthesized chemosensor SP23. In the ACN:H2O (9:1) solvent mixture, SP23 is more sensitive and selective to BF3 than the other competing ions. It is interesting to note that a ratiometric emission shift changes from blue to yellow fluorescence was observed with the BF3 ion. The detection limit of 7.58 nM was discovered using this chemosensor, which was less than the previous findings. After administering triethylamine as a regenerating material to the BF3 complex, the SP23 could be made reversible. Furthermore, the aggregation investigations indicate that the Aggregation Induced Emission (AIE) phenomenon was followed by the Aggregation Caused Quenching (ACQ) phenomenon. Ultimately, a paper-based test kit was constructed, using the established chemosensor, for practical usage.