Adamantylated trisimidazolium-based tritopic guests and their binding properties towards cucurbit[7]uril and β-cyclodextrin.

Two new homotritopic guests based on tris(benz)imidazolium salts with adamantane binding sites were prepared. NMR and calorimetric titration experiments revealed that each of the three sites independently binds β-cyclodextrin (β-CD) or cucurbit[7]uril (CB7) units to form binary host-guest complexes with 1:3 stoichiometry. The association constants for the single binding site for β-CD and CB7 were determined using titration calorimetry and are in the order of 10 and 10 dm mol, respectively. In addition, both guests were able to form ternary systems with β-CD and CB7 in ratios of 1:1:2 and 1:2:1, respectively. [ABSTRACT FROM AUTHOR]