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Thionation-enhanced through-space electronic coupling and excited-state dynamics in helicene diimides
Analia D'Orazio-Colman1, Amalnadh T2, Sona Saji2
1Julius-Maximilians-Universität Würzburg, Institut für Organische Chemie, Am Hubland, D-97074 Würzburg, Germany.
Chemical Communications (Cambridge, England)
|May 7, 2026
Summary
Thionation, a simple substitution, enhances electronic coupling in helical molecules. This modification stabilizes energy levels and improves charge delocalization in [8]helicene diimides.
Area of Science:
- Organic Chemistry
- Materials Science
- Photophysics
Background:
- Helically constrained π-systems are crucial for advanced electronic and optical materials.
- Controlling through-space electronic coupling is key to tuning material properties.
- Heteroatom substitution offers a pathway to modify electronic structures.
Purpose of the Study:
- To investigate the effects of thionation on electronic coupling in [8]helicene diimides.
- To explore how sulfur incorporation impacts the LUMO energy level and charge delocalization.
- To understand the influence of thionation on excited-state dynamics.
Main Methods:
- Synthesis of thionated [8]helicene diimide.
- UV-Vis absorption and emission spectroscopy.
- Electrochemical measurements (cyclic voltammetry).
- Density Functional Theory (DFT) calculations.
Main Results:
- Thionation led to significant stabilization of the Lowest Unoccupied Molecular Orbital (LUMO).
- Electronic coupling between imide units nearly doubled in the thionated compound.
- Enhanced charge delocalization and altered excited-state dynamics were observed.
- Spectroscopic and computational data confirmed these effects.
Conclusions:
- Thionation is an effective strategy for enhancing electronic communication in helical systems.
- The modified [8]helicene diimide exhibits improved charge transport characteristics.
- This work provides insights into designing novel organic electronic materials through heteroatom substitution.
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