The NBO analysis reported the presence of two primary types of charge transfers in the system under investigation. The first type is commonly associated with hydrogen bonding and involves the donation from the lone pair (LP(X -)) of the anion to the antibonding orbital of the H-C bond (BD * (CH)). The second type involves the donation from the anion to the centrally positioned nitrogen atom within the tetrahedral structure, which is assumed to carry a positive charge in ammonium-based models. The NBO results clearly indicate the establishment of weak to moderate hydrogen bond interactions upon complexation, as well as a weak charge transfer from the LP of the anion to the orbital involving The QTAIM analysis presented in Table provides additional support for the aforementioned findings. Overall, the charged complex exhibits higher density and Laplacian values compared to the neutral ones, albeit falling within the expected range for such interactions. Figure represents the molecular graphs specifically associated with ammonia_based_CH 3 -Cl and ammonium-based_CH 3 -Cl. These graphs visually depict the distinct hydrogen bond interactions formed between the Cl -ion and the hydrogen atoms of the CH 3 groups. The figures illustrate the electron density at various BCPs and also display the corresponding Laplacian values. The densities identified at the BCPs are comparatively lower than those observed within the iminium complexes because of the weaker HB donor. Additionally, the Laplacian values exhibit a similar range, yet consistently remain one order of magnitude lower when compared to the tight ionpair formations detected in the salts. To finish this section, the charge difference within the monomers and upon complexation for both, neutral and charged complexes will be discussed (Figures and.6 and S1.7).