Supramolecular FRET modulation by pseudorotaxane formation of a ditopic stilbazolium dye and carboxylato-pillar[5]arene

Abstract

In this paper we introduce a new approach towards the modulation of fluorescence resonance energy transfer (FRET). Two stilbazolium dyes (A, D) exhibiting opposite fluorescence responses upon complexation with anionic, water soluble carboxylato-pillar[5]arene (WP5) were covalently linked via click chemistry, yielding a FRET-capable ditopic indicator (G). The pseudorotaxane formation of G with WP5 in pure water induced fluorescence enhancement combined with the modulation of the FRET process due to the interaction of the macrocycle with the two fluorophore units.