A benzobisimidazolium-based fluorescent and colorimetric chemosensor for CO2

Area of Science:

• Analytical Chemistry
• Organic Chemistry
• Materials Science

Background:

• Accurate detection of carbon dioxide (CO2) is crucial for environmental monitoring and industrial processes.
• Existing CO2 sensors often require specific bases or complex activation methods.
• Development of efficient and sensitive CO2 detection systems remains an active research area.

Purpose of the Study:

• To introduce a new sensor system for the fluorescent and colorimetric detection of carbon dioxide (CO2).
• To investigate the mechanism of CO2 detection activated by fluoride.
• To demonstrate a sensor system operating without the need for an exogenous base.

Main Methods:

• Utilized a tetrapropyl benzobisimidazolium salt activated by fluoride ions.
• Employed spectroscopic analyses (e.g., NMR, UV-Vis) to study the reaction mechanism.
• Conducted theoretical calculations to support the proposed reaction pathway.

Main Results:

• Successfully developed a sensor for both fluorescent and colorimetric CO2 detection.
• Demonstrated that fluoride activates the benzobisimidazolium salt in the absence of an external base.
• Identified the formation of an N-heterocyclic carbene intermediate upon fluoride induction.
• Observed the reaction of the carbene intermediate with CO2 to yield an imidazolium carboxylate.

Conclusions:

• The described sensor offers a novel approach for CO2 detection.
• Fluoride-induced N-heterocyclic carbene formation is the key mechanism for CO2 sensing.
• The system's ability to operate without an exogenous base simplifies its application.