A [2]Rotaxane Flip Switch Driven by Coordination Geometry

The carrot is better than the stick! Changes in the metal coordination geometry of the capping group in a [2]rotaxane ligand results in molecular switching by reorienting a trapped macrocyclic component (see picture). Switching was successfully initiated when the metal coordination site was made more attractive (square planar), but not when the metal coordination site was made less attractive (octahedral).