Harnessing Electrostatics to Unlock Cage Catalysis: A Combined Experimental Computational Approach

The ability to convert one molecule into another is central to socioeconomic progress. It allows raw materials, such as oil or coal, to be converted into high utility products, such as drugs, fuels and plastics. Most molecules, however, do not readily transform themselves into others and instead require the use of a catalyst. These species dramatically speed up the conversion of one molecule into the next, so, for example, a chemical reaction that would normally take millions of years only takes a few seconds. Catalysts can also have other benefits, such as they can be very selective, wherein using a catalyst produces a single product whereas often many are formed. This is especially important for applications in the pharmaceutical industry.

Many of the catalysts we use on a day-to-day basis are man-made. However, nature already provides a wide range of catalysts, known as enzymes, which make possible the chemical processes upon which life depend. Despite their common function of speeding up chemical reactions, synthetic catalysts and enzymes work in fundamentally different ways. Artificial catalysts often rely on rare, metallic elements, which are excellent catalysts but are often difficult to work with because they are not stable in air. In contrast, enzymes, which are also excellent catalysts, principally use "organic elements" (carbon, hydrogen, nitrogen, oxygen) so they are completely stable as they need to function in the body.

In this research, we aim to make catalysts that mimic the way that enzymes work. This is a difficult task because enzymes are large polymers, containing thousands of atoms organised in complex three-dimensional structures. The active part of the enzyme is also hidden away in a semi-hollow interior. We will thus design synthetic catalysts that also possess a hollow interior, so they can replicate the active part of an enzyme, however, they are also much simpler and easier to prepare because they spontaneously assemble when simple building blocks (like Lego pieces) are mixed together. Once the molecules are bound inside these assembled catalysts, they become activated and undergo a chemical reaction to selectively generate the product. The development of a new class of simple and "user-friendly" catalysts that possess the proficiency of either biological or "conventional" catalysts has the potential to deliver cost-effective routes to high utility products and thus provide significant socioeconomic benefits.