The molecular properties of heterocyclic and homocyclic hydrogen-bonded complexes evaluated by DFT calculations and AIM densities.

This theoretical study presents a comparative analysis of the molecular properties of heterocyclic (C2H4O...HF and C2H5...HF) and homocyclic (C3H6...HF) hydrogen-bonded complexes. Initially, the equilibrium geometries of these complexes were analyzed in detail at the B3LYP/6-311++G(d,p) level of theory. Subsequently, the interaction energies and polarizabilities were also evaluated, as well as the infrared stretch frequencies and absorption intensities. In addition, by combining intermolecular criteria and charge density concepts, calculations of Bader's theory of atoms in molecules were used to determine the maxima and minima for electron density in order to measure the strength of the n...H and ppi...H hydrogen bonds. Finally, the possibility of an F...H(alpha) secondary interaction between the fluoride (F) of hydrogen fluoride and the axial hydrogen atoms (H(alpha)) of the C2H4O and C2H5N heterocyclic rings was explored.