The question of intramolecular hydrogen bonding in 2-flouroethanol

Abstract

Several investigations have shown, by a variety of spectral techniques, that 2-fluoroethanol (1) exists both in the liquid and vapor state, predominantly (>95%) in the conformation. with hydroxyl and fluorine gauche to one another. Notable is the recent electron-diffraction study in which 1 was shown to be greater than 90% gauche in the vapor phase at 156°. In every instance, this marked conformational preference for the gauche form has been attributed to the formation of a strong intramolecular hydrogen bond between the electronegative fluorine atom and the hydroxyl proton which are in close proximity in this configuration. That this is the case is presumably also supported by the observation that the CCF bond angle of 107.7° is compressed relative to fluoroethane.

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