HETEROCYCLIC HYDROGEN BONDED COMPLEXES INVOLVING THREE AND FIVE MEMBERS: A QUANTUM CHEMICAL STUDY ABOUT THE CASE OF THE NONLINEARITY ON THE HYDROGEN BONDING

B3LYP/6-311++G(d,p) and B3LYP/6-31G(d,p) theoretical levels combined with topological calculations based on the theory of atoms in molecules (AIM) were used to study the formation of intermolecular interactions on heterocyclic hydrogen-bonded complexes formed by ethylene oxide, sulfide oxide, 2,5-dihydrofuran, thiophene, and the hydrofluoric acid. As observed, the electrophilic attack of the hydrofluoric acid occur aligned to the n lone pair of the heteroatom of the cyclic systems, the modeled structure of the hydrogen-bonded complexes is interpreted in terms of the intermolecular parameters of the (n ⋯ HF) hydrogen bond, such as its R(n ⋯ HF) distance, ΔEC binding energy, and the new υ(n ⋯ HF) stretching vibrational mode. From these criteria, a relationship between the strength (R, ΔEC and υ) of the hydrogen bonds and its nonlinearity deviation was verified, which is formed by a secondary interaction between the hydrofluoric acid and axial hydrogen atoms of the cyclic structure. Moreover, even though the Bader's electronic density partitioning has been projected with low dependence from ab initio wave functions, it is shown here that the 6-31G(d,p) basis sets characterized the secondary interaction in geometrical point of view, as well as by means of the AIM protocol through the specific calculation of bond critical points between the fluoride and the axial hydrogen atoms.