Ce⁴⁺-Triggered Stable Pyrene Radical Cation Formation in a Hydrogen-Bonded Organic Framework Enabling on-Site...

Area of Science:

• Materials Science
• Analytical Chemistry
• Environmental Science

Background:

• Detecting environmentally relevant cerium(IV) ions (Ce⁴⁺) on-site is difficult with current analytical techniques.
• Existing methods often lack the sensitivity and selectivity required for real-world applications.
• There is a need for innovative sensing platforms for rapid and reliable Ce⁴⁺ detection.

Purpose of the Study:

• To develop a highly sensitive and selective dual-mode sensor for Ce⁴⁺ detection.
• To utilize a pyrene-based hydrogen-bonded organic framework (Py-HOF) for visual sensing applications.
• To demonstrate the feasibility of radical-based optoelectronic HOF materials for metal ion sensing.

Main Methods:

• Synthesized a pyrene-based hydrogen-bonded organic framework (Py-HOF).
• Exploited Ce⁴⁺-induced one-electron oxidation to form stable pyrene cation radicals (Py•⁺) within the HOF.
• Utilized dual-mode colorimetric and fluorometric detection with a response time under 8 seconds.
• Developed a 3D-printed portable sensor for smartphone-assisted quantification.

Main Results:

• The Py-HOF exhibited a visible color change from yellow to cyan with increasing Ce⁴⁺ concentration.
• Fluorescence quenching was observed, enhancing visual resolution in the dual-mode detection.
• The sensing process was reversible using ascorbic acid (AA).
• Achieved a limit of detection (LOD) of 0.3 µM for Ce⁴⁺ in water and 0.6 µM for AA in juice.

Conclusions:

• The developed Py-HOF provides a sensitive, selective, and visually detectable platform for Ce⁴⁺.
• Radical-based optoelectronic HOF materials show promise for dual-mode metal ion sensing.
• The portable sensor facilitates rapid on-site quantification of Ce⁴⁺ and AA in real samples.