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Parameters Influencing the Photochemical Cyclodehydrochlorination (CDHC) Reaction
Anthony Jolly1, Charles-Émile Fecteau1, Paul Andrew Johnson1
1Département de chimie and Centre de Recherche sur les Matériaux Avancés (CERMA), Université Laval, Québec, QC, Canada, G1V 0A6.
Chempluschem
|February 9, 2024
Summary
Photochemical cyclodehydrochlorination (CDHC) efficiently synthesizes polycyclic aromatic hydrocarbons and graphene nanoribbons. Reaction efficiency is influenced by functional groups and conditions, with kinetics correlating to Hammett
Area of Science:
- Organic Chemistry
- Photochemistry
- Materials Science
Background:
- Photochemical cyclodehydrochlorination (CDHC) is a key reaction for synthesizing polycyclic aromatic hydrocarbons (PAHs) and graphene nanoribbons (GNRs).
- Limited studies have explored the parameters influencing the efficiency of the CDHC reaction.
Purpose of the Study:
- To investigate the impact of reaction conditions on the outcome of the CDHC reaction.
- To examine the effect of functional groups on the o-terphenyl scaffold in CDHC reactions.
Main Methods:
- Systematic variation of reaction parameters for CDHC.
- Study of substituent effects on the o-terphenyl scaffold.
- Computational modeling to elucidate the reaction mechanism.
Main Results:
- Reaction kinetics correlate with Hammett's constant for electron-donating and electron-withdrawing groups on the chlorinated ring.
- Successful CDHC achieved using 365 nm light and a triplet sensitizer.
- Computational analysis identified three intermediate structures and the rate-limiting step of the reaction.
Conclusions:
- Reaction conditions and functional group substitution significantly influence CDHC efficiency.
- The CDHC reaction mechanism involves specific intermediates and a defined rate-limiting step.
- This work provides a foundation for optimizing CDHC for PAH and GNR synthesis.
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