Transition metal-complexed catenanes and rotaxanes as molecular machine prototypes.

Transition metal-containing catenanes and rotaxanes are ideally suited to build molecular machines and motors; in the present review article, three examples from our group are discussed which consist of (i) a fast-moving electrochemically-driven pirouetting machine, (ii) a linear rotaxane dimer whose behaviour is reminiscent of muscles, in the sense that it can be stretched or contracted and (iii) a light-driven machine consisting of a catenane constructed around a ruthenium(II) centre.