Light-matter interactions play a key role in human society, whether in the exchange of information or the development of modern technology. When such light-matter interactions become strong enough, they form hybrid light-matter states which lead to fundamental changes in material and chemical properties. A given molecular vibration of a small organic molecule in the liquid phase can be partitioned into two or more energetically distinct states by coupling to the vacuum field, a phenomenon known as vibrational strong coupling (VSC).
The reactivity of organic molecules is intimately intertwined with their molecular vibrations. The ability to selectively alter the energies of specific molecular vibrations therefore has enormous consequences for chemical reactivity. The main goal of this proposal was to explore how VSC can be used to modulate the selectivity of simple organic reactions, to understand which functional groups and reaction mechanisms are most susceptible to VSC, as well as to explore the effect of VSC on catalytic reactions.
Overall, the project has developed VSC as a powerful and versatile tool for molecular sciences. VSC was found to not only change the rate of reactions, but to influence their site selectivity. In particular, it has a significant effect on the stereoselectivity of electrocyclic ring opening reactions. VSC plays a critical role in molecular symmetry, which leads to a larger change in chemical reactivity than would be expected from the energy difference between the two resulting hybrid states, known as the Rabi splitting. These results encourage further study on the chemical reactions in cavities to understand how VSC alters their mechanism and chemical reactivity. During the course of this project, we started a collaboration with a large European chemical company to investigate the industrial applications of this technology.
