Spectroscopic Studies of Alcohols: Vi. Intramolecular Hydrogen Bonds in Ethanolamine and Its O- And N-Methyl Derivatives

The competitive intramolecular [Formula: see text] hydrogen bonding in ethanolamine and N-methylethanolamine has been studied in dilute C2Cl4 solution by means of the temperature dependence of the fundamental OH and NH stretching bands. Of the three conformers identified for each of these compounds, the least stable shows a distinct band which is assigned to a "terminal" OH group involved in an intramolecular [Formula: see text] hydrogen bond. Enthalpy differences between conformers are reported and discussed, and compared with those found for the conformational equilibria in 2-methoxyethylamine and N,N-dimethyl-ethanolamine.