The synthesis of crown ether-appended dichlorofluoresceins and their selective Cu~(2+) chemosensing

摘要

Dichlorofluorescein derivatives with two aza-crown ether binding units were prepared by the Mannich reaction and their chemosensing behaviors toward transition metal ions were investigated. An 18-crown-6 ether derivative exhibited pronounced Cu~(2+)-selective fluorescence signaling, with selectivity over other common physiologically important alkali, alkaline earth and transition metal ions. The compound also displayed 1:1 complex formation with Cu~(2+) ion, with a detection limit of 2.9 x 1 10~(-6) M in an aqueous 50% DMSO solution at pH 7, showing that it may offer potential as a chemosensor for the detection of submillimolar Cu~(2+) ions in physiological environments. A 15-Crown-5 ether analogue also revealed selective Cu~(2+) signaling, although with somewhat diminished selectivity compared with its 18-crown-6 counterpart.