Macrocyclic Hamilton receptor-shuttling dynamics in [2]rotaxanes

Inherent movement of a macrocycle comprising a multi-site hydrogen-bonding Hamilton-type receptor in a series of [2]rotaxanes was investigated by dynamic and VT NMR. In these rotaxanes, the varying nature and number of hydrogen-bond motifs and stations on the molecular axles influenced ring dynamics. Triazole stations interact selectively by hydrogen bonding with the isophthalamide amide bonds present in the Hamilton macrocycle and fast shuttling (72 kHz at 25 degrees C) was observed in a two-station variant.