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Carbazole-Based Colorimetric Anion Sensors
Krystyna Maslowska-Jarzyna1, Maria L Korczak1, Jakub A Wagner1
1Biological and Chemical Research Centre, Faculty of Chemistry, University of Warsaw, Żwirki i Wigury 101, 02-089 Warsaw, Poland.
Molecules (Basel, Switzerland)
|June 2, 2021
Summary
New carbazole-based receptors with electron-withdrawing groups show enhanced anion binding and acidity. One derivative acts as a colorimetric sensor, but proton transfer limits selectivity for basic anions.
Area of Science:
- Supramolecular Chemistry
- Organic Chemistry
- Materials Science
Background:
- 1,8-diaminocarbazoles are versatile building blocks for anion receptors due to their carbazole core and hydrogen bonding capabilities.
- Carbazole derivatives are explored for anion sensing applications.
Purpose of the Study:
- To synthesize novel 1,8-diaminocarbazole derivatives with electron-withdrawing substituents for anion sensing.
- To investigate the anion binding properties and acidity of these new carbazole receptors.
- To develop a colorimetric anion sensor based on carbazole scaffolds.
Main Methods:
- Synthesis of 3,6-dicyano and 3,6-dinitro-1,8-diaminocarbazole precursors.
- Conversion of precursors into model diamide receptors.
- Anion binding studies using spectroscopic methods.
- Evaluation of colorimetric and fluorescent responses to anions.
Main Results:
- Synthesized carbazole receptors with enhanced anion affinities and increased acidities.
- A nitro-substituted carbazole derivative functions as a colorimetric anion sensor with visible color and fluorescence changes.
- The sensor showed poor selectivity due to dominant proton transfer interactions with basic anions.
Conclusions:
- Highly acidic and strongly binding carbazole receptors were developed.
- The potential application of these receptors in organocatalysis or pH-switchable anion transport was highlighted.
- Proton transfer can be a dominant interaction, affecting sensor selectivity.
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