Simply structural, reversible and chemical stable ratiometric pH-responsive fluorescence probe of pyrene derivatives...

The pyrene group is commonly used as a fluorophore in ratiometric fluorescence probes. However, these probes almost exclusively utilize the monomer/excimer of the pyrene group to achieve ratiometric fluorescence recognition for analytes. In the study, three structurally simple, mono-substituted pyrene derivatives, namely pyrene-1-ol (Probe1), pyren-1-ylboronic acid (Probe2), pyrene-1-carboxylic acid (Probe3) utilize their protonation or deprotonation effects to influence the electronic excited state of the pyrene group, thereby achieving sensitive ratiometric fluorescence recognition of pH. Among them, Probe1 and Probe2 have been verified to function in alkaline environments with pH values ranging from 8.1 to 12.1 and 9.4 to 13.1, respectively, with pKa values of 8.9 and 11.1. Meanwhile, Probe3 performs optimally in weak acidic conditions with a pH range of 2.3-5.2, having a pKa value of 4.8. Additionally, three fluorescence probes exhibit excellent photo-stability, recyclability, and resistance to ionic interference. Furthermore, the three probes can also achieve ratiometric fluorescence detection of pH in environmental water sources such as tap water and Pearl River water, as well as fluorescence response to pH in living GS cells of epinephelus coioides.