This project will explore the interplay between conformation and aromaticity in annulenes. Specifically, the morphology of the sigma framework of annulenes will be perturbed via replacement of the internal protons with deuterium atoms. The changes in pi-delocalization that takes place will be monitored by NMR spectroscopy. Measurements of the relative ring currents in deuterated and protiated annulenes and their respective dianions will lead to insight into the relative importance of the sigma and pi frameworks in terms of aromatic and antiaromatic character.
With this RUI Award, the Organic and Macromolecular Chemistry Program supports the research of Professor Cheryl D. Stevenson of Illinois State University. Professor Stevenson's research will explore a phenomenon known to chemists as aromaticity, referring not to an olfactory characteristic but to a circumstance whereby the stability of a particular molecule is greater than expected due to a specific arrangement of its bonding electrons. In order to carry out this study, large ring-like molecules known as annulenes will be synthesized and an isotope of hydrogen incorporated at specific locations within the molecule. This hydrogen isotope, deuterium, will display certain behavior depending upon its location among the bonding electrons as well as whether the conditions for aromaticity are met. A molecular-scale MRI known as NMR will be used to probe the deuterium atoms.
