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Probe Type II Band Alignment in One-Dimensional Van Der Waals Heterostructures Using First-Principles Calculations
Published on: October 12, 2019
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Diastereomeric Configuration Drives an On-Surface Specific Rearrangement into Low Bandgap Non-Benzenoid Graphene
Federico Villalobos1,2, Jesús I Mendieta-Moreno2, Jorge Lobo-Checa3,4
1Departamento de Química Orgánica, Universidad de Granada (UGR), Unidad de Excelencia de Química UEQ, C. U. Fuentenueva, Granada 18071, Spain.
Journal of the American Chemical Society
|February 19, 2025
Summary
The initial stereochemistry of cyclooctatetraene dictates its transformation into a graphene nanoribbon. This rearrangement yields a novel nanostructure with the lowest reported bandgap for all-carbon chevron-like graphene nanoribbons.
Area of Science:
- Organic Chemistry
- Materials Science
- Surface Science
Background:
- Stereochemistry, the 3D arrangement of atoms, is vital for molecular function.
- While typically from sp3 hybridization, 3D structures also arise in sp2 molecules via helical or twisted forms.
- On-surface synthesis enables atomic-scale control for studying stereochemical effects.
Purpose of the Study:
- To investigate the role of initial diastereomeric configuration in surface-induced molecular rearrangement.
- To synthesize and characterize novel graphene nanostructures with unique electronic properties.
Main Methods:
- On-surface synthesis on a chevron-like graphene nanoribbon.
- Bond-resolved scanning tunneling microscopy (BR-STM).
- Theoretical ab initio calculations.
- Scanning tunneling spectroscopy (STS).
Main Results:
- Demonstrated the critical influence of initial diastereomeric configuration on skeletal rearrangement.
- Successfully transformed a cyclooctatetraene moiety into a cyclopenta[c,d]azulene structure within a graphene nanoribbon.
- The resulting cyclopenta[c,d]azulene chevron-like graphene nanoribbon exhibited the lowest bandgap reported for such all-carbon structures.
Conclusions:
- Stereochemistry plays a crucial role in directing on-surface synthesis outcomes.
- This study provides a pathway for designing novel graphene nanostructures with tailored electronic properties.
- Highlights the potential of on-surface synthesis for creating exotic molecular architectures.
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