Design, Synthesis, and Reactivity of Diboryl- and Aminoboryl Carbenes

is synthesizing compounds of the carbenoid class that formally are electron deficient at carbon. While most compounds feature carbon atoms that form four chemical bonds, there are a handful in which carbons form three or fewer bonds. The isolation of such new carbon species has been impeded by the belief that they are inherently unstable. This project will use methods developed by the PI to prepare compounds called carbenes, which contain only two bonds to carbon. In this project, these methods will be extended to previously unknown carbenes where the carbon atom is bonded to two boron atoms. The availability of these species has the potential to add to our understanding of how chemical reactions of carbon take place, permitting control of the reactivity of carbon-containing compounds. Ultimately, results derived from these studies are expected to advance the manufacturing of fine chemicals and materials by providing more selective approaches to synthesis. Professor Hudnall's laboratory participates in local outreach activities with high schools, a children’s museum to connect the community at large with undergraduate and graduate research. The idea that singlet carbenes feature a p2 electronic configuration has been theorized since the 1960s, but thus far these species have largely eluded isolation in the laboratory. Utilizing synthetic methodologies developed by the principal investigator, diborylcarbenes (R2B-C-BR2) and the related aminoboryl carbenes (R2N-C-BR2) will be prepared. As some of the targeted species may be non-isolable, this research project is seen as a high risk/high reward effort. The targeted diborylcarbenes are predicted to have the p2 electron configuration, a configuration not observed in other carbenes. Importantly, these carbenes are predicted to be quite electrophilic at the carbene carbon atom and may provide opportunities for new manifolds of carbene reactivity. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.