Fig. 5. Graphical representation of data extracted from Fig. 4: (a) blue curve, chemical shift of one of the signals of 1-adamantane-carboxylic acid as a function of pH; (b) red curve, occupancy of the cavity of H as a function of pH on the basis of 1H NMR integrals. The two curves mirror each other and intersect at the pK a of 1-adamantane-carboxylic acid.
