Noncovalent bonding interactions are broadly important to the field of organic chemistry. Intermolecular interactions including van der Waals forces, π−π stacking, ion-π interactions, and hydrogen bonding are all capable of modulating local electron density, resulting in altered physical or chemical properties. This presentation reports combined computational and experimental evidence for nitrogen−fluorine halogen bonding in Ag(I)-initiated radical C−H fluorinations. Pyridines form [N−F−N]+ halogen bonds with the fluorine source Selectfluor to facilitate single-electron reduction by catalytic Ag(I). Pyridine electronics affect the extent of halogen bonding, which requires careful treatment of electron correlation to yield accurate predictions, leading to significant differences in selectivity between mono- and di-fluorinated products. Electronic structure calculations show that halogen bonding to various pyridines alters the single-electron reduction potential of Selectfluor, which is consistent with experimental observations. This work suggests new ways for considering relatively weak interactions, such as fluorine-based halogen bonding, to optimize desired product formation in reaction optimization.

Evidence for nitrogen-fluorine halogen bonding in silver-initiated fluorination reactions

2019 Fall National Meeting

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.