Dynamics of sterically hindered F⁻ + i-C₃H₇Cl reaction: An enhancement of indirect mechanisms.

This article focuses on the atomistic reaction dynamics of the fluoride anion (F⁻) with isopropyl chloride (i-C₃H₇Cl), investigating the competition between bimolecular nucleophilic substitution (SN2) and base-induced elimination (E2) reactions through direct dynamics simulations at a collision energy of 1.9 eV. The study finds that despite similar potential energy barriers, the anti-E2 pathway predominates over the inv-SN2 pathway, with both direct and indirect mechanisms contributing, and a notable increase in indirect reaction dynamics compared to the analogous F⁻ + ethyl chloride (C₂H₅Cl) reaction. Enhanced ion-induced dipole and van der Waals interactions in the entrance-channel complex of F⁻ + i-C₃H₇Cl prolong interaction times, favoring indirect mechanisms and influencing reaction selectivity. These findings provide detailed atom-level insights into sterically hindered SN2/E2 systems and align with experimental scattering observations, highlighting the significant role of methyl substitution at the α-carbon in modulating reaction dynamics.