Isolation and structure of an "Imploded" cryptophane

Container crushing: Thermal liberation of the encapsulated guest in a cryptophane has been shown to cause conformational "implosion" in the solid state. The resulting collapsed form is kinetically stable, can be isolated, and its unexpected structure has been elucidated by X-ray diffraction. It eventually re-inflates, however, to the occupied container-like species on standing in solution (see scheme).