Ab initio predictions of the structures and energetics of some hydrogen-bonded complexes of methanol and dimethylamine with dimethyl ether and trimethylamine

The optimized structures of the four complexes formed from methanol and dimethylamine with dimethyl ether and trimethylamine, containing OH ... O, OH ... N, NH ... O and NH ... N hydrogen bonds, have been elucidated by means of a series of ab initio calculations using the GAUSSIAN-92 computer program at the Hartree-Fock level with the 6-31G** basis set. The interaction energies and hydrogen-bond enthalpies, as well as some related molecular properties, have been determined and are discussed in the light of the natures of the four types of hydrogen bond present in these complexes.