A pseudo thiacrown compound formed by hydrophobic interaction of its lipophilic parts in water: Ag~+-selecitive fluorophore in water

摘要

Amphiphilic podand (3) was prepared by conventional thioether synthesis in ethanol. It shows exclusive selectivity toward Ag~+ ion in a liquid-liquid extraction. It was also found to exhibit selective fluorescence decrease only in the presence of Ag~+ ion in water. From the fluorometric titration, the complexing stability constant toward Ag~+ in water estimated to be long K_a = 4.2, which value is ocmparable to cyclic dithia-18-crown-6. This extraordinarily high value was caused by a pseudo cyclic structure formed in water, which was supported by ~1H NMR spectral analysis.