Hydrogen Bonding and Proton Transfer in Fluoropyridine-HBr Complexes

Abstract

Previous work in the Phillips group explored substituent and matrix effects on hydrogen bond strength in N—HCl systems (NH3–HCl, CH3CN–HCl, fluoropyridine–HCl) In the fluoropyridine-HCl work hydrogen bond strength varied greatly across 9 complexes. The addition of fluorines to ring weakened hydrogen bonds. Shifts of H-Cl stretch in infrared spectra paralleled fluorine substitution and matrix environment. Stronger complexes shifted to proton-transfer structures in simulated solvents; weaker complexes did not. In this work we explore the analogous HBr complexes.