Novel surfactant-like pyrene derivatives: synthesis, fluorescent properties and sensing applications

Two novel non-ionic surfactant-like pyrene derivatives containing a triazole unit, 2-(4-((bis(2-hydroxyethyl)amino)methyl)-1H-1,2,3-triazol-1-yl)-N-(4-(pyrene-1-sulfonamido)butyl)acetamide (PSDA-TDEA) and 2-(4-(((2-hydroxyethyl)amino)methyl)-1H-1,2,3-triazol-1-yl)-N-(4-(pyrene-1-sulfonamido)butyl)acetamide (PSDA-TEA) were designed and synthesized. Fluorescence studies revealed that the two fluorophores aggregate in aqueous phase, and the critical aggregation concentrations (CACs) of them are ∼1.2 × 10−4 M and ∼8.5 × 10−5 M, respectively. It was demonstrated that the profiles of the emission spectra of the two compounds are both dependent on the micro-polarities of their mediums. Specifically, the ratio of I399/I380, of which the two emissions appearing at 399 and 380 nm, respectively, are both coming from the monomer emissions of the pyrene residue of the compounds, increases gradually and significantly with increasing the micro-polarity of the medium at which the probes stay. As expected, PSDA-TDEA and PSDA-TEA could probe the formation and transformation of the aggregates of some typical amphiphiles. Meanwhile, PSDA-TDEA also shows selective sensing to the presence of lanthanum ion and europium ion, and the detection limits (DL) are 1.48 and 1.14 ppm, respectively. Clearly, PSDA-TDEA and PSDA-TEA as created could be used as multi-functional fluorescent probes, at least for sensing polarity and some lanthanide ions. These probes are superior to others in using due to their better solubility in aqueous phase, which must bring convenience for pre-treatment of the samples under test.