Mechanical Synthesis

Abstract

Rotaxanes consist of one or more ring-shaped molecules that are positioned around a thread or linear segment that is capped by bulky end groups, much like beads on an abacus. Despite their importance in the design of molecular machines, for example, they are difficult to make, as one typically needs to slip the thread through the ring and then cap the ends before the ring slips off. Most synthetic methods rely upon building recognition units into both the thread and the ring so that they stick together, which has limited the number of molecules that can be made.