Figure 2.

(A) ¹H NMR spectral changes (400 MHz, DMSO-d₆) of 4-OI titrating into Zn-NH-pyr. (B) Schematic representation of 4-OI encapsulation by endo and exo cavities of Zn-NH-pyr. (C) UV-Vis spectral changes of Zn-NH-pyr upon the addition of 4-OI. (D) Plot of ∆A vs. 4-OI/Zn-NH-pyr molar ratio based on the UV-Vis spectroscopic titration data with the non-linear fit of the titration data to Hill equation. (E) Job's plot for the determination of the endo-encapsulation stoichiometry of Zn-NH-pyr and 4-OI binding, indicating a binding stoichiometric ratio of 1:1.