Recent Advances in the Chemical Synthesis of Lasso Molecular Switches

Interlocked and interwoven molecules are intriguing structures that can behave as molecular machines. Among them, the [1] rotaxane molecular architecture is unique, since it defines a lasso-type shape, that, if well designed, can be tightened or loosened depending on an external stimulus. This chapter describes an overview of the main strategies used to reach [1] rotaxanes to date and then focuses on the few examples of [1] rotaxanes reported in the literature that behave as monolasso or double-lasso molecular machines. Different motions are illustrated like the loosening-tightening of lassos or the controllable molecular jump rope movement which is specific to the double-lasso structure.