Meldola lecture: understanding the properties of urea and thiourea inclusion compounds

Much of the intrinsic appeal of structural science arises from the fact that structural behaviour at the molecular level often resembles macroscopic structures that we can see in the world around us. In the same way that we perceive beauty in the symmetries and forms of macroscopic objects, there is an equally enthralling beauty in the way that nature fashions symmetry and diversity within the architectures of crystalline solids. In the field of inclusion chemistry, for example, many direct analogies can be drawn between the concepts of inclusion in the microscopic and macroscopic worlds, but the scientific interest and importance of inclusion chemistry extends far beyond such structural comparisons. As this article demonstrates, solid organic inclusion compounds can exhibit a diversity of interesting and important fundamental properties, which can form the basis of a range of important applications.