Interplay between a Foldamer Helix and a Macrocycle in a Foldarotaxane Architecture

The design and synthesis of a novel rotaxane/foldaxane hybrid architecture is reported. The winding of an aromatic oligoamide helix host around a dumbbell-shaped thread-like guest, or axle, already surrounded by a macrocycle was evidenced by NMR spectroscopy and X-ray crystallography. The process proved to depend on the position of the macrocycle along the axle and the associated steric hindrance. The macrocycle thus behaves as a switchable shield that modulates the affinity of the helix for the axle. Reciprocally, the foldamer helix acts as a supramolecular auxiliary that compartmentalizes the axle. In some cases, the macrocycle is forced to move along the axle to allow the foldamer to reach its best recognition site.

Automated summary

A novel rotaxane/foldaxane hybrid architecture was designed and synthesized, with the winding of an aromatic oligoamide helix host around a dumbbell-shaped thread-like guest already surrounded by a macrocycle evidenced by NMR spectroscopy and X-ray crystallography. The position of the macrocycle along the axle and the associated steric hindrance were found to affect this process, with the macrocycle acting as a switchable shield modulating the affinity of the helix for the axle. Conversely, the foldamer helix acted as a supramolecular auxiliary compartmentalizing the axle.