Well-defined redox-active supramolecular assemblies

The field of supramolecular chemistry has emerged to mimic the second coordination sphere found in enzymes with synthetic ‘cages’. By rationally designing and synthesizing building blocks, a wide range of differently shaped, charged and sized cages are available. Although these cages have been demonstrated to enable reactions to proceed with interesting reactivity and selectivity, often not possible without the second coordination sphere, the cage structures themselves typically act as ‘static’ capsules. Within the conventional design strategies, there are limited to no options to influence, switch or tune the framework or the interior or ensuing host-guest interactions.
This research contributes to the fundamental understanding of the role of the structural components of a supramolecular assembly, through the design and synthesis of stimuli-responsive systems. The combined results from the various Chapters show that, depending on the size of the building blocks, intramolecular interactions within the assembly can occur. These interactions may affect the redox properties and, in cases where the cavity is large enough, also the host-guest chemistry of these non-covalent assemblies. Furthermore, the choice of metal ion may influence the optical properties or the stability, which therefore affects the extent of redox-switchability of the cages, for instance in the context of switchable catalysis. This research illustrates that relative small changes within a supramolecular assembly can result in stark changes in the overall properties. These results are expected to enable the more straightforward, rational design and application of (redox-based) stimuli-responsive cages.