Highly selective fluorescence turn-on sensor for fluoride detection.

Area of Science:

• Supramolecular Chemistry
• Analytical Chemistry
• Materials Science

Background:

• Triazole and triazolium compounds are known to interact with anions via hydrogen bonding.
• C-H···anion interactions offer a pathway for developing novel sensing mechanisms.
• Selective detection of fluoride is crucial for environmental monitoring and public health.

Purpose of the Study:

• To demonstrate fluoride-induced deprotonation of a C-H bond for sensing applications.
• To develop a highly selective fluorescence turn-on sensor for fluoride detection.
• To assess the sensor's performance in aqueous media for practical fluoride monitoring.

Main Methods:

• Synthesis of a fluorene-triazolium based fluorescent probe.
• Investigation of C-H···F(-) interactions using fluorescence spectroscopy.
• Characterization of the binding mechanism via (1)H NMR titrations.
• Preparation of test papers for practical fluoride detection.

Main Results:

• Evidence of fluoride-induced deprotonation of the C-H bond was observed.
• The developed sensor exhibited a highly selective fluorescence turn-on response to fluoride.
• The sensor detected fluoride in aqueous solutions down to 1.9 ppm.
• Successful application in preparing test papers for fluoride estimation in drinking water.

Conclusions:

• The C-H bond in the fluorene-triazolium system can be selectively deprotonated by fluoride.
• A novel fluorescence turn-on sensor for fluoride detection based on this principle has been successfully developed.
• The sensor demonstrates potential for practical, on-site monitoring of fluoride levels in drinking water.