Triple-Standard Hypochlorite Quantitative Array Enabled by Precise Stokes Shift Modulation in D-π-A Chemodosimeters.

Area of Science:

• Chemical sensing
• Fluorescent probes
• Materials science

Background:

• Designing chemodosimeters with large Stokes shifts is crucial for improving optical sensing signal visualization.
• D-π-A (Donor-π-Acceptor) structures are key components in developing advanced fluorescent chemodosimeters.

Purpose of the Study:

• To synthesize and investigate three D-π-A fluorescent chemodosimeters with varying electron-releasing strengths.
• To explore the relationship between electron-releasing modulation, Stokes shift, and sensing mechanisms.
• To evaluate the chemodosimeters' performance for detecting hypochlorite (ClO⁻).

Main Methods:

• Synthesis of three D-π-A fluorescent chemodosimeters using 2-(3-cyano-4,5,5-trimethylfuran-2(5H)-ylidene) malononitrile (TCF) as the electron-withdrawing group.
• Modulation of electron-releasing strength to tune electrophilicity and Stokes shift.
• Evaluation of sensing performance, including limit of detection (LOD), response time, and selectivity for ClO⁻ detection.
• Validation using a portable quantitative array detection platform.

Main Results:

• Decreasing electron release increased electrophilicity by 1.449 kcal/mol and improved Stokes shift to 201 nm.
• Sensing modes transitioned from fluorescence quenching to ratiometric fluorescence and then to fluorescence-on.
• Achieved low LODs for ClO⁻ (37.0, 5.1, and 1.0 nM) with rapid response (<5 s) and high selectivity.
• Demonstrated practical quantitative detection of ClO⁻ using a portable array platform.

Conclusions:

• The developed D-π-A chemodosimeters offer sensitive and visualized detection of ClO⁻.
• The design and modulation strategy provide a new approach for identifying oxidants and hazardous chemicals.
• These findings advance the field of optical sensing and chemodosimeter design.