Upon analysing the charge of the monomer and its variation upon complexation (Figure .1), we found that the N atom's charge remains unchanged upon interaction with the anions, while C3 becomes slightly more negatively charged, in agreement with the charge transfer process described by the NBO analysis. Through analysis of the monomer, it becomes evident that the positive charge is not confined to the N atom but delocalised within the C atoms of the scaffold. Finally, we turned our attention to investigating the electronic behaviour of the intermolecular interactions studied. In this regard, QTAIM has been widely shown to be an excellent tool for analysing various properties of the electron density and the nature of chemical bonding within a molecule, including bond strengths, and understanding the presence of charge transfer or electronic delocalisation within the molecule. First, the electron density at the BCPs of the relevant bond was studied, as well as their corresponding Laplacian values (∇ 2 ρ(r), Table ). In the topological analysis, (∇ 2 ρ(r)) plays a very im-portant role in the characterisation of chemical bonding, providing the physical basis for the well-known electron-pair model of Lewis. A positive ∇ 2 ρ(r) indicates the dominance of excess kinetic energy, corresponding to local depletions, and is associated with non-covalent interactions (lower positive values) and ionic bonds (higher positive values).