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Qualitative Identification of Carboxylic Acids, Boronic Acids, and Amines Using Cruciform Fluorophores
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Achieving Simplified and Tunable Flexibility in Carborane-Based Emitters for Quantitative Vapochromic VOC Sensing
Zhaojin Wang1, Bo Chen1, Huike Zhang1
1Key Laboratory for Advanced Technology in Environmental Protection of Jiangsu Province, Yancheng Institute of Technology, Yancheng 224051, China.
Analytical Chemistry
|April 11, 2023
Summary
New carborane (Cb) emitters offer a simplified approach to quantitative photoluminescence (PL) sensing of volatile organic compounds (VOCs). These Cb-based sensors demonstrate fast, reusable detection of benzene and tetrahydrofuran (THF) vapors.
Area of Science:
- Materials Science
- Chemical Sensing
- Photophysics
Background:
- Photoluminescence (PL) sensing is a cost-effective method for detecting air pollutants like volatile organic compounds (VOCs).
- Existing tetraphenylethylene (TPE)-based and carborane (Cb)-based sensors often have multiple VOC-responsive sites, complicating quantitative analysis.
- Developing simplified and tunable PL sensors is crucial for achieving accurate quantitative detection.
Purpose of the Study:
- To design and synthesize novel Cb-based emitters with tunable flexibility for quantitative PL sensing.
- To investigate the vapochromic properties and sensing mechanisms of these new Cb derivatives.
- To establish a quantitative sensing platform for specific VOCs using the developed materials.
Main Methods:
- Synthesis of three emissive dibenzothiophene (DBT)-alkynylated carboranes (Cb-1/2/3).
- Characterization of optical properties (PL spectroscopy) in crystals and VOC-incorporated films.
- Crystallographic studies and theoretical calculations to understand molecular structure, dimerization, and VOC interaction.
- Vapochromic sensing experiments with benzene and tetrahydrofuran (THF) vapors.
Main Results:
- Cb-3 exhibited distinct vapochromic behavior, shifting emission from green/green-yellow to yellow/orange upon VOC incorporation.
- Crystallography revealed interlocked dimerization of Cb-3, with through-space conjugation of DBT moieties causing PL redshift.
- Theoretical calculations confirmed dimer stability and suggested individual DBT rotation under VOC influence.
- Linear relationships were established between PL maxima photon energy and concentrations of benzene and THF.
- Fast response (6 s) and recovery (3–5 s) with good reusability were demonstrated for THF sensing.
Conclusions:
- DBT-alkynylated carboranes provide a promising platform for quantitative vapochromic sensing of VOCs.
- The dimeric model effectively addresses the flexibility challenge in PL sensor design.
- The developed sensors offer high sensitivity, rapid response, and reusability for air pollutant detection.
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