Intramolecular hydrogen bonding and conformation of 1,3-propanediol

Conformational differences in molecules of 1,3-propanediol with variations of medium, temperature, and phase composition appear in their IR and Raman spectra. In the gas phase and in dilute solutions of 1,3-propanediol in CCl₄ forms with intramolecular hydrogen bonding (IHB) and without it exist in comparable amounts. The difference in the weighted mean energies of the corresponding groups of conformers was found from the temperature dependence of the intensities of the bands for free _OH and bounded _OH. By calculating the conformational term of E^* and by using the energy values of the 25 conformers of the diol molecules, calculated by molecular mechanics methods, the IHB energy was determined for two of them.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 10, pp. 2277–2284, October, 1991.