Supramolecular chemistry and molecular recognition

This work exploits cyclodextrins as molecular hosts. Our early work in this area resulted in pharmaceutical formulations that are in everyday clinical use worldwide. In more recent studies modified cyclodextrins are being developed and exploited as molecular scaffolds for the construction of catalyst, molecular ratchets, shuttles, tweezers and switches, and photochemical devices.

Another application of cyclodextrins involves their use to control the assembly of the components of chemical reactions, to facilitate the reactions and alter the outcomes. The cyclodextrins thereby act as reaction vessels, but at the molecular level. In this regard, we have developed demonstration systems to change the regio- and stereo-selectivity of reactions, and increase their rates by up to 100,000 times. We have also been exploring the synthesis of cyclodextrin rotaxanes, catenanes, knots and daisy chains of various topologies.

These form the basis of molecular devices such as ratchets and motors, temperature and light sensors, photochemical frequency switches and molecular tweezers. Solid state and solution studies of cyclodextrin host-guest complexes and rotaxanes show that these assemblies may be designed to exploit the cyclodextrins as insulators of molecular filaments formed by the guests. This has potential, for example, in the development of microelectronic systems.