Band Shape of the OH Stretching Vibration in Aliphatic Alcohols. Evidence for the Occurrence of an Intramolecular Interaction

Abstract

The band shape of the OH stretching vibration in a series of aliphatic alcohols has been investigated. The asymmetric shape which occurs in the majority of alcohols is due to an overlapping band on the low‐frequency side of the major band. The asymmetry, which is concentration independent, is shown to occur in the deuterated species and in the first overtone vibration as well. The temperature dependence of the minor band has been investigated and a negative ΔH found which suggests that the minor band is due to an intramolecular interaction. A model is proposed in which the hydrogen of a CH group at the γ position interacts with the lone pair electrons at the hydroxyl oxygen atom. The model qualitatively predicts the correlation between the formation constant and the number of available γ‐CH groups which is experimentally observed.