Dynamic Chiral Cyclohexanohemicucurbit[12]uril

NMR and DFT studies of chiral cyclohexanohemicucurbit[12]uril indicate that the macrocycle adopts a concave octagon shape with three distinct ranges of conformational flexibility in solution. Methylene bridge flipping occurs at temperatures above 265 K, while urea monomers rotate at temperatures above 308 K resulting in the loss of confined space within the macrocycle.