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

Area of Science:

• Supramolecular Chemistry
• Organic Chemistry
• Analytical Chemistry

Background:

• Indolocarbazole-pyridine hybrid foldamers display fluorescence in random conformations.
• Helical folding of these foldamers leads to fluorescence quenching due to aryl plane stacking.
• Anion binding disrupts the helical structure, restoring fluorescence.

Purpose of the Study:

• To develop a fluorescence turn-on probe for anion detection.
• To utilize the anion-induced fluorescence recovery property of hybrid foldamers.

Main Methods:

• Synthesis of indolocarbazole-pyridine hybrid foldamers.
• Spectroscopic analysis of fluorescence properties.
• Investigation of anion binding effects on foldamer conformation and fluorescence.

Main Results:

• Foldamers are highly fluorescent in extended conformations.
• Fluorescence is quenched in helical conformations due to π-π stacking.
• Anion binding (sulfate, fluoride) perturbs helical structure, leading to fluorescence recovery.
• Demonstrated a fluorescence turn-on sensing mechanism.

Conclusions:

• Indolocarbazole-pyridine foldamers can act as sensitive fluorescence turn-on probes for specific anions.
• The conformational change triggered by anion binding is key to the sensing mechanism.
• This approach offers a new strategy for anion detection.