Research Fellows Directory
Dr Charlotte Willans
University of Leeds
Metals are used widely in academia and in industry both for catalysis and in biomedicine. Ligands are molecules that bind to metal centres and serve to stabilise them, in addition to playing a potential role in the application of the metal complex. For example, it may contain groups that target a specific molecule in biomedicine, or it may direct catalysis to determine the outcome of a reaction. N-heterocyclic carbenes (NHCs) are carbon based ligands which can coordinate to almost any element through the donation of two electrons. The electronic and steric properties of NHCs can be varied greatly through modification of groups on both the nitrogen the backbone of the heterocycle. Chelating and macrocyclic ligands coordinate to metal centres through donation at two or more sites. It has long since been known that as the number of donors in a ligand increases, the stability of the resulting metal complex is likely to increase. Our research focuses on the design and preparation of chelating and macrocyclic ligands that incorporate NHC moieties. We aim to prepare metal-NHC complexes with increased stability and tuneability for application in catalysis and biomedicine.
One of the applications that we have probed is the cytotoxicity of our silver-NHCs against cancer cells. We have found that many of our complexes exhibit significant activity and have built up structure-activity relationships. We are working in collaboration with the Institute of Cancer Therapeutics in Bradford to determine the mechanism of action of these complexes. We are also using a new class of ligand that we have designed and prepared, namely NHC-carboranes, in important catalytic processes such as the functionalisation of methane to prepare useful molecules.