Molecular Recognition within a Self-Assembled Cylindrical Host.

A change in geometry is necessary on entry into the capsule: a supramolecular associate approximately 1.8 nm long (see schematic representation), which consists of two halves stabilized by hydrogen bonds, influences the intra- and intermolecular interactions of the guest molecules encapsulated. Thus tertiary amides and anilides such as 1, which exist in solution preferably as E rotamers, are fixed in the Z conformation inside the capsule for steric reasons.