Complexation Analysis of Water-Soluble Phosphate Salt Pillar[5]arene with Acridine Orange

The host-guest complex of water-soluble phosphate salt pillar[5]arene (PP5A) and cationic fluorescent dye acridine orange (AO) was constructed, and studied with ultraviolet spectrum (UV), infrared absorption spectrum (IR), molecular fluorescence spectroscopy (MFS), and nuclear magnetic resonance (NMR) spectra (1H NMR and NOESY). And then, the effect of pH and two surfactants, including sodium dodecyl sulfate (SDS) and cetyltrimethylammonium bromide (CTAB) on the fluorescence intensity of AO/PP5A complex system were investigated. Finally, the complexation mode and energy of PP5A with AO and CTAB were calculated by molecular docking. The results showed that AO and PP5A formed a 1:1 host-guest complex. PP5A reduced or quenched the fluorescence intensity of AO in the pH range of 3~11. The addition of SDS and CTAB did not affect the fluorescence intensity of AO/PP5A complex significantly. The fluorescence changes generated by AO and PP5A complexation can provide a theoretical basis for the design of fluorescence sensors.