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Highly Selective On-Surface Ring-Opening of Aromatic Azulene Moiety
Lulu Wang1, Xinnan Peng1, Jie Su1
1Department of Chemistry, National University of Singapore, 3 Science Drive 3, 117543, Singapore.
Journal of the American Chemical Society
|December 23, 2023
Summary
Researchers precisely opened the seven-membered ring in azulene molecules on a surface. This breakthrough in polycyclic aromatic hydrocarbon chemistry was achieved by controlling strain and aromaticity, enabling new molecular reconstructions.
Area of Science:
- Surface Chemistry
- Organic Chemistry
- Materials Science
Background:
- Polycyclic aromatic hydrocarbons (PAHs) are vital in chemistry and biology.
- Breaking stable aromatic C-C bonds in PAHs is exceptionally difficult.
- Controlling PAH transformations is key for advanced applications.
Purpose of the Study:
- To achieve precise and selective on-surface ring-opening of azulene.
- To understand the mechanism and driving forces of PAH ring-opening.
- To explore new methods for manipulating PAH structures.
Main Methods:
- On-surface synthesis and manipulation under mild conditions.
- Bond-resolved scanning probe microscopy for structural identification.
- Density functional theory (DFT) calculations for mechanistic insights.
Main Results:
- Successfully achieved selective ring-opening of the seven-membered ring in azulene.
- Identified reaction products and elucidated the reaction mechanism.
- Demonstrated that manipulating local aromaticity via strain and cyclodehydrogenation drives the reaction.
Conclusions:
- Provides a novel method for controlled PAH ring-opening.
- Offers fundamental insights into the chemical driving forces of these reactions.
- Opens avenues for designing and reconstructing complex aromatic systems.
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