Catalytic activation via π-backbonding in halogen bonds.
Faraday Discuss
; 244(0): 241-251, 2023 Aug 11.
Article
em En
| MEDLINE
| ID: mdl-37186101
ABSTRACT
The role of halogen bonding (XB) in chemical catalysis has largely involved using XB donors as Lewis acid activators to modulate the reactivity of partner Lewis bases. We explore a more uncommon scenario, where a Lewis base modulates reactivity via a spectator halogen bond interaction. Our computational studies reveal that spectator halogen bonds may play an important role in modulating the rate of SN2 reactions. Most notably, π acceptors such as PF3 significantly decrease the barrier to substitution by decreasing electron density in the very electron rich transition state. Such π-backbonding represents an example of a heretofore unexplored situation in halogen bonding the combination of both σ-donation and π-backdonation in this "non-covalent" interaction. The broader implications of this observation are discussed.
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01-internacional
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MEDLINE
Idioma:
En
Ano de publicação:
2023
Tipo de documento:
Article