Catenanes are supramolecules that consist of two macrocycles threaded through one another such that they cannot be pulled apart without breaking a covalent bond (like two links of a chain). Rotaxanes are supramolecular consisting of a macrocyclic "ring" threaded about a dumbbell-shaped "axle." Our group is investigating new ways to prepare these, and more complex architectures like trefoil knots using main group elements to template the assembly. Once prepared, these can act as very selective host molecules for a range of guests including transition metals and anions because the central cavity of the catenane has a "protein-like" three-dimensional cavity buried away in the centre of the interlocked rings. This project will involve a reasonable amount of organic synthesis, as well as some host-guest binding studies and potentially some X-ray crystallography.