The role of London dispersion interactions in strong and moderate intermolecular hydrogen bonds in the crystal and in the gas phase

Two variants of density functional theory computations have been applied to characterization of hydrogen bonds of the 1-(2-hydroxylethyl)-3-methylimidazolium acetate ([C(2)OHmim][OAc]), i.e. with and without inclusion of dispersion interactions. A comparison of the results demonstrates that London dispersion interactions have very little impact on the energetical, geometrical, infrared spectroscopic and electron density parameters of charge-assisted intermolecular hydrogen bonds functioning both in the crystal of the [C(2)OHmim][OAc] and in the isolated [C(2)OHmim](+) [OAc](-) ion pairs. (C) 2017 Elsevier B.V. All rights reserved.