The electrochemical measurements indicate that the receptor systems studied allow for multiple oxidation acts that are irreversible. To gain more insights into this process, we performed calculations on cations carrying charges between +1 and +4, thus accounting for up to four oxidation acts. We restricted these calculations to free receptors and receptors bound with KF. The resulting oxidation potentials are provided in Table . The first two oxidation acts are related to electron extractions from HOMO orbitals shown in Fig. . This agrees with the CVs of the ion receptors and their parts performed in acetonitrile (see section 2.1 in SI). In the case of KF-bound receptors, this leads to H + atom abstraction from one of the NH groups by a fluoride anion (see Fig. ) as manifested in F -…H(N) distance change from ca. 1.2 -1.4 Å in the ground state (simple hydrogen bond) to 0.98 -0.99 Å in a doubly charged species (negative charge on ionophore and HF molecule). Interestingly, in the case of 5FSQC6, the hydrogen abstraction occurs at the position proximal to the fluorinated phenyl ring, while for the CF3SQC6 receptor, another hydrogen is being abstracted (proximal to the corona moiety). Full hydrogen abstraction happens after the fourth oxidation act. This is accompanied by deformation of the four-membered ring. While no H abstraction is observed for free ionophores even after the fourth oxidation act, the deformation of the strained, fourmembered ring is also visible here.