Introducing the Charles Stirling Lecture Series.

Have you ever wondered what academics do outside of their taught lecture courses? The content of lectures is not always reflective of the research they do daily. The Charles Stirling Lecture series has been established by ChemSoc and the CRS, Chemistry Researchers Society, to inform students of the wide variety of research conducted here in Sheffield.

Every two weeks, during term time, a different academic member of staff will give a talk aimed at informing students of their research area. The talks are aimed at an undergraduate audience with the sole purpose of informing and entertaining.

The series started on Wednesday the 15th of February, with Prof. Charles Stirling, FRS, introducing the series by speaking about his career path and activities aimed at promoting chemistry outside of the department. Included in his introduction was a summary of some of the research he performs as a postdoctoral researcher in Prof. N. Williams group, 19 years after his retirement.

Prof. Mike Ward, the Head of Department, was the first academic to provide students with a snapshot of the research performed in his group.

Mike’s research focuses around the field of self-assembly. This is where molecules arrange themselves spontaneously into complicated structures. Simple geometric arguments can be used to construct complex exotic structures. For example, the angles between the coordination sites of metal complexes and complimentary ligands can be combined to build 3-dimensional complexes from cubes to dodecahedrons.

Combined with self-assembly is also host-guest chemistry. This can be considered comparable to the role of some proteins, where molecules, the guest, will bind to a cavity, the host. The self-assembly of cage complexes is well-suited to this field of chemistry due to the formation of a cavity in the centre. Molecules are bound within the host by simple, weak intermolecular forces such as Van Der Waals forces or Hydrogen bonding to name only two.

What makes this field interesting is that the chemistry within cavities can be unexpected. For example, cavities can stabilise previously unstable molecules or could lead to alternative reaction pathways induced by the confined space in the cavity and the increased proximity of reactants.

Mike combines these two fields in his research into molecular cages. One area Mike is currently targeting is catalysis. This uses host-guest chemistry to bind molecules within the cavity of the cage where the reaction will occur and the product is released.

Schematic of the Kemp eliminationThe example highlighted was the Kemp elimination (see the diagram), in which the cage catalysed reaction increased the rate by a factor of 2×105! This rate improvement is on the scale of proteins, the target of most catalytic research. But, catalysis is not the only application, cages could also be used for drug delivery, where the drug would be released from the cavity at a designated point in the body. The possibilities are only limited by imagination.

Further information can be found in Prof. Wards paper in Nature Chemistry

The next Lecture is on Wednesday March 1st at 1pm in the Dainton Building Lecture theatre 1, with Dr Seb Spain presenting his research.

Written By
Joe Clarke

With thanks to Prof. Charles Stirling, Prof Mike Ward and Rebecca Gibson.