Molecular meccano, 52 - Template-directed synthesis of a rotacatenane

A [2]catenane, able to bind pi-electron-rich guests inside the cavity of on e of its two macrocyclic components has been designed and synthesized using supramolecular assistance. This recognition motif has been exploited to te mplate the formation of a so-called rotacatenane - i.e., a molecule compose d of a dumbbell-shaped component threaded through the cavity of one of the two mechanically interlocked formation composed macrocyclic components of a [2]catenane. The structure of this [2]catenane, as well as that of a model [2]catenane, have been characterized unequivocally by single-crystal X-ray analyses. Furthermore, some of the co-conformational changes associated wi th these mechanically interlocked molecules in solution have been probed by variable-temperature H-1-NMR spectroscopy.