Year: 2025
Type: article
Abstract: Both the carbonyl and hydroxyl O atoms of the carboxyl group are capable of acting as electron donor in the context of noncovalent bonds. These two O atoms of acetic acid are each allowed to form an H-bond with HCl and a halogen bond with IF, and the interactions are monitored by quantum chemical calculations. The electrostatic potential on the carbonyl O is more negative than that on OH, and the HOMO is weighted toward the carbonyl. The interaction energies are consequently considerably stronger for the CO. A series of ligands are added to the carboxyl group that extract electron density from the carbonyl O and add density to OH. These arrangements enhance the interaction energies involving OH, some by nearly 50%. These same ligands have a lesser effect on bonds involving CO, many of which are actually strengthened, despite the reduced magnitude of its negative potential. Consequently, the CO remains the favored site for an electrophile, regardless of the ligands that might be present.
Source: ChemPhysChem
Author: Steve Scheiner
Institution: Utah State University
Language: English
Subfield: Physical and Theoretical Chemistry
Field: Chemistry
Domain: Physical Sciences
Open Access status: bronze
Funder: National Science Foundation
OpenAlex ID: W4416624947