Towards a rational design of molecular switches and sensors from their basic building blocks

A fundamental understanding of the thermodynamics and kinetics of mechanically interlocked molecules, such as [2]rotaxanes, will contribute to a more rational design of new molecular machines. This Chapter describes the influence of chemical modifications and the role of the physical environment on the ground state thermodynamics and the shuttling and switching kinetics of several tetrathiafulvalene- and 1,5-dioxynaphthalene-containing [2]rotaxanes. A comparison between the properties of these bistable rotaxanes and model host-guest complexes of the corresponding pi-electron donating recognition units with the pi-electron accepting cyclophane, cyclobis(paraquat-p-phenylene), has been made, resulting in useful guidelines for the design of new bistable rotaxanes with specific, desirable physical performances.