Fluorescent calix[4]triazole for selective fluoride anion sensing.

Area of Science:

• Analytical Chemistry
• Materials Science
• Environmental Science

Background:

• Fluoride ions (F-) are essential for dental health and bone treatment but pose risks at high concentrations.
• Accurate detection of fluoride is vital for monitoring health and environmental safety.
• Existing fluoride detection methods lack sensitivity, selectivity, or speed.

Purpose of the Study:

• To develop a selective and sensitive fluorescent chemosensor for fluoride ion detection.
• To investigate the anion-binding properties of the Py-CT4 sensor.
• To establish Py-CT4 as a tool for monitoring fluoride in biological and environmental samples.

Main Methods:

• Synthesis of Py-CT4, a fluorescent chemosensor comprising pyrene linked to calix[4]triazole via an ester bridge.
• Investigation of Py-CT4's fluorescence response to various anions, particularly fluoride ions (F-).
• Analysis of the mechanism of fluorescence quenching induced by fluoride binding.

Main Results:

• Py-CT4 demonstrated significant and selective fluorescence quenching in the presence of fluoride ions (F-) compared to other anions.
• The fluorescence intensity of Py-CT4 decreased proportionally with increasing F- concentration, enabling quantitative detection.
• The sensing mechanism involves electron transfer initiated by hydrogen bonding and F- induced deprotonation of the calix[4]triazole moiety.
• Py-CT4 exhibited high selectivity for F- even in complex matrices with competing anions.

Conclusions:

• Py-CT4 is the first macrocyclic receptor utilizing a charge-neutral 1,2,3-triazole for selective F- recognition via fluorescence quenching.
• The sensor offers advantages over traditional methods, including high sensitivity, rapid response, and ease of use.
• Py-CT4 shows promise as a valuable tool for monitoring fluoride levels in biological and environmental systems, contributing to public health and safety.