Abstract: A new kind of fluoroionophore——a flavone derivative linked to 12-crown-4 was synthesized and char acterized.The spectroscopy and photo physical behavior of the fluor oionophore for its complexation with different cations were investigated.The complexation causes a significant change of spectro scopy and photophysical properties and is attributable to the enhancement of the cation-induced intramo lecular charge transfer via directinter action of the cation bound to the crown and the carbonyl group of flavone.Based on the determination of the stability constant,the selectivit y for Ca²⁺ was found in the fluoroiono phore,which was totally different from the parent crown——12-crown-4.That could tentatively account for the high selectivity.It might be valuable for designing the new fluor oionophore linked crown.

Key words: Molecular recognition, Lariat crown ether, Fluoroionophore, Flavone derivatives