Fluorescent macromolecular chemosensors for highly and selectively detecting of 2, 4, 6-trinitrophenol

Abstract

Among nitroaromatic compounds with similar structures, 2,4,6-trinitrophenol (TNP) exhibits strong biological toxicity and explosion hazard. Therefore, detection of TNP is of great importance. In this work, two novel fluorescent macromolecular chemosensors P1 and P2 were prepared using boron-dipyrromethene (BODIPY) as the fluorophore. After the preparation of small BODIPY molecule M1, another small molecule M2 with two aldehyde groups was synthesized by two consecutive Vilsmeier-Haack reactions. Then, M2 reacts with trans-cyclohexane-1,4-diamine and 1,4-phenylenediamine respectively to obtain two macromolecules P1 and P2 via Schiff Base forming reaction. The results suggested that P1 and P2 could recognize TNP only while other aromatic/nitroaromatic compounds cannot cause significant fluorescence intensity response. When TNP exist, these fluorescent macromolecular chemosensors produce significant fluorescence quenching. At the same time, because the electron-rich Schiff base and the electron-deficient TNP have the structural basis of chemical interaction, these two macromolecular sensors also have excellent sensitivity to TNP, and the excellent recognition limit of detection reach as low as 0.017 μM. High sensitivity and selectivity have been applied to test TNP in lake water samples as well.