The results of studies on hydrogen bonded dimers which involve hydroxyl group acting as both a donor and acceptor in an intermolecular
hydrogen bonding are presented. Systems formed by α-hydroxy-COX moieties, where X is OH, NH2 or OCH3, have been investigated in the gas-phase and in solution and compared with analogous patterns observed in crystals. The RHF/6-311++G** level of theory has been employed to compute energies and optimise geometries in the isolated state. The Polarisable Continuum
Model with the same basis set has been employed to include the solvation effects. Correlation corrections at the MP2 level
and zero-point corrections at the HF level have been calculated in order to verify the energy differences between conformers.
In summary, it has been found that hydroxyl group may be regarded as complementary to the α-hydroxy-COX group and most of such arrangements are stable not only in the isolated state but also in liquid media, particularly
in a polar one.