A multibranched carbazole linked triazine based fluorescent molecule for the selective detection of picric acid

Abstract

A multibranched carbazole linked triazine centre based molecule (TRZ-Cz) was synthesized using the Wittig–Horner reaction and used as a fluorescent probe for the detection of picric acid (PA). The thermally more stable alkylated carbazole moiety was purposely introduced into TRZ-Cz, and could play a significant role in enhancing the thermal stability and solubility, reducing the steric hindrance, and increasing the intramolecular charge transfer (ICT) between the carbazole donor and the triazine acceptor moiety. In this paper, we employed the TRZ-Cz molecule in the detection of different nitroaromatic compounds (NACs). Among these various NACs, hydroxyl containing nitro compounds are effectively quenched; this may be due to the π–π interactions between TRZ-Cz and the acidic phenolic hydroxyl groups. The TRZ-Cz molecule exhibits a high quenching response to PA with high sensitivity and selectivity, compared to other analytes. TRZ-Cz shows good aggregation-induced emission (AIE) effects in a H₂O/THF (7 : 3 v/v) mixture and these aggregates are also able to detect PA. This study offers details for the design and preparation of a new multibranched molecular fluorescent probe for the detection of PA, with low toxicity, easy synthesis steps, and high selectivity.