Selective fluorescence sensing of salicylic acids using a simple pyrenesulfonamide receptor

Abstract

Pyrenesulfonamide and pyreneamide probes (2–5) were synthesized, and they were used in the sensing of salicylic acid derivatives. The ability of 3 to sense various salicylic acid derivatives was examined by UV-visible, fluorescence, and NMR spectroscopy; it was further supported by DFT calculations. The sensing of salicylic acid derivatives resulted in a significant quenching of the pyrene monomer emission. Among the tested salicylic acid derivatives, probe 3 exhibited the highest binding constant with 3,5-dinitrosalicylic acid (K_a = 2.65 × 10⁵ M⁻¹, measured at a 1 : 1 molar ratio in EtOH).