FIGURE 2.

Different eightfold coordinated complexes of K⁺ ions considered in this investigation. ΔΔG refers to the free energy of partitioning a K⁺ ion from liquid water (reference environment) into the respective eightfold coordinated chemistries embedded in a quasiliquid phase. The interligand H-bonds are depicted using dashed lines connecting the hydrogen (white) and oxygen atoms (red). The chemistry and architecture that favors K⁺ ion partitioning precisely matches the binding sites S1–S3 found in the selectivity filters of K-channels.