*2.5. Theoretical Calculations*

Gaussian-16 [28] program package was used for the calculations reported in this work. For the energies and wavefunction calculations we have used the PBE0 [29] functional in combination with Grimme's dispersion correction (D3) [30] and the triple-ζ basis set def2-TZVP [31]. The molecular electrostatic potential (MEP) surfaces have been computed at the same level of theory and using the 0.001 a.u. isosurface to emulate the van der Waals surface. The experimental crystallographic coordinates have been used to evaluate the interactions in the solid state. This level of theory and methodology was used before to investigate similar interactions [32–35]. The Bader's quantum theory of "Atoms in molecules" (QTAIM) [36] and the noncovalent interaction index (NCIPlot) index [37] methods were used to characterize the hydrogen bonding interactions by means of the AIMall program [38]. The dissociation energies of the H-bonding interactions have been evaluated using the methodology proposed by Espinosa et al. [39] based on the potential energy density (Vr) at the bond critical points (CPs).
