Helical Aromatic Foldamers Functioning as a Fluorescence Turn-on Probe for Anions

Indolocarbazole-pyridine
hybrid foldamers are strongly fluorescent
in an extended random conformation, but the fluorescence is completely
quenched upon folding to a helical conformation due to the compact
stacking between aryl planes in the backbone. Anion binding disturbs
the helical conformation, thus regenerating the fluorescence of the
foldamers. This unique property has been utilized to develop a fluorescence
turn-on probe for anions such as sulfate and fluoride.