An Interesting Small Molecule Fluorescent Probe for A Narrow Range (12.5~13) pH and DMSO Detection

Abstract

Aims: The development of a sensitive and visual analytical method for detecting and monitoring the change of pH has always attracted great interest because it plays significant role in chemical reactions, environmental monitoring, and biological systems. Methods: In this paper, a simple condensation reaction from readily available substrates 2-hydroxy-1-naphthylaldehyde and malononitrile has been carried out to produce probe L with good aggregation-induced luminescence, and its chemical structure was confirmed by 1H NMR, 13C NMR and ESI-MS. Objective: There is a conjugated system containing electron-withdrawing cyano group and electron-donating hydroxyl group in molecular structure of probe L, and which exhibits obvious fluorescence intensity and visible color change through intramolecular charge transfer (ICT) under different pH conditions. Results: Probe L assumes excellent fluorescence intensity in DMF/H2O (1:9, v:v) mixed solvent system, and exhibits good reversibility in a very narrow range of pH values (pH = 12.5~13), which indicates that it can be used for the analysis and visual detection to pH change in DMF/H2O system. Conclusion: In addition, probe L can also selectively identify solvent DMSO by the induction of fluorescence quenching, which means that probe L may be used as the indicator for the detection and monitoring of trace amount of DMSO.