C-F Bonds as "Frozen" Nucleophiles: Unconsummated SN2 Reactions

Abstract

In this note, we present a series of rigid molecules that show close enforced interactions between Ar-F moieties and -CH₂X groups in a "tetrel bond" configuration similar to a nascent S_N2 attack. We explore the spectroscopic, crystallographic, and chemical reactivity consequences of these unusual interactions, including significant through-space spin-spin couplings, short C-F···CH₂X distances, and differential S_N1 and S_N2 reaction pathways. We also reveal experimental evidence of carbon-based tetrel bonds influencing chemical reactivity in solution. Finally, density functional theory (DFT) calculations are employed throughout this study to confirm and illuminate our experimental data.