The first enantiomerically pure members of the cucurbituril family, (all-S)- and (all-R)-cyclohexylhemicucurbit[6]urils (cycHC), were synthesized in good yield (up to 85%). The crystal structure of this new macrocycle clearly shows its ball-like shape. CycHC monomers adopt a "zigzag" conformation, having apolar cyclohexyls around the openings and polar ureas in the middle. Cyclohexylhemicucurbit[6]urils formed complexes with halides, carboxylic acids and amines and diastereomeric complexes with methoxyphenylacetic acid in organic media. The association constants of cycHC with small organic compounds were evaluated by diffusion NMR in chloroform.

A computational study of (all-S)-cyclohexylhemicucurbit[6]uril and its complexes with anions (Cl(-), Br(-), I(-) and HCOO(-)), the proton (H(+)) and non-dissociated acid (HCl, HBr, HI and HCOOH) guests was performed. The geometries of guest-host complexes were optimized via density functional theory using the BP86 functional, SV(P) basis set and Stuttgart pseudopotentials for iodide. Binding affinities and their trends were evaluated at the BP86/TZVPD level of theory. In addition, the quantum theory of atoms in molecules was used to gain insight into guest-host interactions. A computational study in the gas phase and ion-mobility mass-spectrometry analysis revealed that the studied macrocycle formed inclusion complexes with anions. Protonation of the macrocycle is preferred at the nitrogen atom pointing inside of the cavity. In the studied conditions, non-dissociated acids formed complexes at the oxygen atom pointing outside of the macrocycle.

The existence of new 7-, 8-, 9-and 10-membered homologues of chiral cyclohexylhemicucurbituril is reported. The barrelshaped (all-R)-cyclohexylhemicucurbit[8]uril ((all-R)-cycHC[8]) was isolated and its complexes with anions were detected in negative ion mode MS. Here, 7-, 9-and 10-membered homologues were detected by HPLC -HRMS. Geometries of all reported macrocycles were calculated using quantum chemical methods, which showed that even-numbered homologues were barrel-shaped and odd-numbered homologues were asymmetrical barrel-shaped with unequal dimensions of the openings. The size of the ((all-R)-cycHC[8]) cavity was comparable to CB[8] and it probably can serve as a chiral host.