Functional Rotaxanes: From Controlled Molecular Motions to Electron Transfer Between Chemically Nonconnected Chromophores

Considered only laboratory curiosities when first synthesized in the late sixties, rotaxanes (a cyclic component threaded onto a dumbbell-shaped linear component) are now relatively easily available through template synthesis. This has led to the development of functional rotaxanes, for example rotaxanes displaying electrochemically or photochemically triggered intramolecular motions like translation of the ring along the dumbbell, or electron transfer between their mechanically linked components (figure).