Ion-induced FRET on-off in fluorescent calix[4]arene

Abstract

(Chemical Equation Presented) A novel calix[4]arene bearing one 2,3-naphthocrown-6 and two coumarin amide units at the lower rim in partial-cone conformation (1) was synthesized as a colorimetric and FRET-based fluorometric sensor for F- and Cs+ ions. Intramolecular FRET from the naphthalene emission to the coumarin absorption affords high fluorescence selectivity toward F- and Cs+ ions. © 2007 American Chemical Society.