Strong hydrogen bonding in aliphatic diol solutions of alkali-metal fluorides

Abstract

Heavy alkali-metal fluorides are soluble in low-molecular-weight liquid aliphatic diols. Low-field shifts in the proton magnetic resonances of selected fluoride–diol solutions may be interpreted as being due largely to strong hydrogen bonding between the fluoride anion and the diol hydroxyls, although cation effects are also evident. Variable-temperature ¹H n.m.r. studies on KF–1,2-ethanediol, CH₃CN–1,2-ethanediol, and neat 1,2-ethanediol have been carried out and values of –(50 ± 10) kJ mol^–1 for ΔH^⊖ and –(130 ± 25) J K^–1 mol^–1 for ΔS^⊖ have been determined for the (F ⋯ HO)^– hydrogen bond.