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Preparation of a Corannulene-functionalized Hexahelicene by Copper(I)-catalyzed Alkyne-azide Cycloaddition of Nonplanar Polyaromatic Units
Published on: September 18, 2016
Cyclodehydrogenation reactions to cyclopentafused polycyclic aromatic hydrocarbons
1Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109, USA. violi@eng.utah.edu
The Journal of Physical Chemistry. A
|July 13, 2006
Summary
This study details the chemical transformations of benzo[c]phenanthrene into cyclopenta[cd]pyrene and benzo[ghi]fluoranthene using electronic structure calculations. It uncovers key isomerization and rearrangement pathways, including bay region chemistry and aryne formation.
Area of Science:
- Computational Chemistry
- Organic Chemistry
- Chemical Physics
Background:
- Polycyclic Aromatic Hydrocarbons (PAHs) are significant environmental pollutants.
- Understanding PAH transformation mechanisms is crucial for environmental and toxicological studies.
- Benzo[c]phenanthrene is an alternant PAH that can convert into nonalternant PAHs.
Purpose of the Study:
- To elucidate the reaction mechanisms for the conversion of benzo[c]phenanthrene to cyclopenta[cd]pyrene and benzo[ghi]fluoranthene.
- To analyze isomerization reactions, including 5/6-ring switching and hydrogen atom scrambling.
- To investigate bay region chemistry and aryne formation pathways.
Main Methods:
- B3LYP/6-31G(d,p) electronic structure calculations were employed.
- Computational analysis of reaction pathways and intermediates.
- Detailed examination of molecular rearrangements and bond formations.
Main Results:
- The study identified specific mechanisms for the conversion of benzo[c]phenanthrene to the target nonalternant PAHs.
- Key steps include benzene ring rupture, five-membered ring formation, and aryne intermediate generation.
- Rearrangement of the aryne leads to annelated cyclopentadienylidenecarbene, which undergoes intramolecular trapping.
Conclusions:
- The computational findings provide a detailed mechanistic understanding of PAH interconversion.
- The identified pathways highlight the complex chemistry involved in PAH transformations.
- This research contributes to the fundamental knowledge of polycyclic aromatic hydrocarbon chemistry.
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