| Summary: | The aim of this research was to investigate intercomponent motion by employing systems where the motion, although difficult to observe directly, has an observable effect on a measurable property in the systems of study. The initial target of this research was to synthesise a [2]polyrotaxane. On cleaving a removable stopper the macrocycle would be free to translate along the backbone of the polymer chain before being irreversibly lost to the system in solution. The initial research presents the attempts to functionalise a rotaxane auxiliary with a polymer chain, firstly by Atom Transfer Radical Polymerisation (ATRP) of a rotaxane initiator, and then by attaching a poly(ethylene glycol) monomethyl ether chain to a rotaxane auxiliary. The design and application of a new rotaxane template motif is also presented. An alternative approach to the study of intercomponent motion is then presented. A series of symmetrical molecular shuttles, defined as a [2]rotaxane comprised of two identical stations that are separated by an alkyl chain, was synthesised. The macrocycle in such systems is known to ‘shuttle’ between the two stations, spending roughly half the time on each station, and this rate can be observed and measured. By reducing the length of the alkyl chain between the two stations, a faster rate of shuttling between the stations was observed. The series incorporated shuttles with different length alkyl (C2, C4, C6, C8, C10, C12) spacers, different stations and different macrocycles. Shuttling or site exchange rates were measured by <sup>1</sup>H Nuclear Magnetic Resonance using Spin Polarisation Transfer by Selective Inversion Recovery (SPT-SIR) technique. We attempt to use the experimental results to validate a theoretical model for the intercomponent motion. Finally a study of a unique tristable molecular shuttle is presented. This unique system displays some of the unanticipated behaviour that highlights our incomplete understanding of interlocked systems.
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