Finally, to obtain a complete picture of the density values at the BCPs involving the anion interaction for all the complexes studied, a graph was generated by plotting the density at the BCPs against the distance between the atoms involved in the interaction. For this particular correlation, all complexes were taken into account, including previous sections and current (Figure ). Only the BCPs corresponding to the same pair of atoms involved were depicted for comparison. The results clearly demonstrate a nearly perfect exponential correlation, indicating a consistent pattern of non-covalent interactions across all complexes. Regarding the different anions under study, PO 4 Me 2 -X systems present the highest density values, corresponding, therefore, to the strongest HB interaction. The strength of the interaction decays with distance.