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Highly Emissive Double π-Helical Molecular Carbons via Nitrogen Integration
Xiaonan Li1,2, Zixin Liu1, Xu Wen1
1Key Laboratory of Organic Optoelectronics and Molecular Engineering, Department of Chemistry, Tsinghua University, Beijing, P.R. China.
Angewandte Chemie (International Ed. in English)
|June 23, 2026
Summary
Researchers developed highly emissive chiral molecular carbons by incorporating nitrogen into cyclooctatetraene (COT) derivatives. These stable, resolved enantiomers exhibit exceptional circularly polarized luminescence (CPL), advancing chiral emitter design.
Area of Science:
- Materials Science
- Organic Chemistry
- Photophysics
Background:
- Chiral π-systems are crucial for advanced materials, but improving their emission efficiency remains a challenge.
- Previous cyclooctatetraene (COT) derivatives lacked significant luminescence.
Purpose of the Study:
- To design and synthesize highly emissive chiral molecular carbons.
- To investigate the impact of structural modifications on luminescence properties and chiral recognition.
Main Methods:
- Synthesis of novel double π-helical molecular carbons with cyclooctatetraphenylene (COTt) or cyclooctahexaphenylene (COTh) cores.
- Introduction of nitrogen via diarylamine/carbazole fusion.
- Chiral resolution using high-performance liquid chromatography (HPLC).
- Photophysical characterization, including fluorescence quantum yield and circularly polarized luminescence (CPL) measurements.
- Theoretical calculations of transition dipole moments.
Main Results:
- Achieved high fluorescence quantum yields up to 98% through nitrogen incorporation.
- Demonstrated high configurational stability allowing for successful chiral resolution.
- Observed a three-fold increase in luminescence dissymmetry factor (glum) from COTt to COTh core.
- Reported CPL brightness up to 110 M-1 cm-1, among the highest for COT-based chiral carbons.
- Theoretical calculations confirmed large transition dipole moments and their alignment.
Conclusions:
- Nitrogen-containing double π-helical molecular carbons are highly emissive chiral emitters.
- Structural modifications significantly enhance luminescence and CPL properties.
- These findings offer insights for designing next-generation luminescent chiral materials.
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