Integrating replication processes with mechanically interlocked molecules

Abstract

In the last twenty years, chemists have devised numerous synthetic chemical systems in which self-replication operates, demonstrating that molecules can replicate themselves without the aid of enzymes and that self-replication is not a prerogative of nucleic acids only. However, the coupling of replication to other recognition-mediated events and its exploitation in the amplification of large supramolecular assemblies, such as mechanically interlocked molecules, have remained unexplored areas. Among mechanically interlocked molecules, rotaxanes represent particularly attractive targets because of their application as molecular switches. This thesis describes how the recognition-mediated synthesis of a rotaxane can be combined to the amplification of its structure by replication. Kinetic models for the integration of self-replication with the formation of a rotaxane are presented. The logical steps required to convert these models into molecular structures through consideration of the design criteria highlighted by the models are discussed and executed. The macrocyclic component is an essential part of a rotaxane. The synthesis of several novel macrocycles is presented. Their ability to bind guests in their cavities through hydrogen bonds was probed. The best macrocycle/guest pairs were integrated in the formation of rotaxanes. Further investigations on the stoppering reaction and on the various recognition processes involved in the system lead ultimately to the construction of self-replicating rotaxanes.