Dr. Larry Sneddon, Department of Chemistry, University of Pennsylvania, is supported by the Inorganic, Bioinorganic, and Organometallic Program of the Chemistry Division to develop new general methodologies for the systematic, high-yield syntheses of polyborane compounds and polymers. The proposed work will result in new ionic-liquid based methods for the synthesis and modification of polyboranes; metal-catalyzed polyborane hydroboration, dehydrogenative-borylation, and alkenylpolyborane metathesis reactions; and routes to poly(organopolyborane) polymers via both early metal catalyzed alkenylpolyborane polymerization and ruthenium-catalyzed alkenylpolyborane ring opening metathesis polymerization (ROMP) reactions. The studies will emphasize the discovery of new reactions and the development of an understanding of their fundamental steps and controlling factors. The new reactions will enable the systematic synthesis of important new alkyl- and alkenylpolyborane, carborane and linked-polyborane molecular compounds, and totally new types of hybrid "polyborane-inorganic" and "polyborane-organic" polymeric materials that have potential technological uses. Understanding the nature of metal-polyborane interactions is of fundamental importance to the discovery and control of new metal catalyzed reactions; therefore, a further central goal of this project is to achieve a better understanding of the structures, bonding, reaction mechanisms, and properties of both polyboranes and metallapolyboranes.
Polyborane compounds have important properties that give rise to applications ranging from uses as cancer agents, high temperature polymers, burn rate modifiers, extractants for nuclear wastes, ceramic precursors and weakly coordinating anions. However, the exploitation of these and other potential uses, as well as the further scientific development of the field, has been seriously hampered by the inability to efficiently synthesize and modify such compounds. There is a clear need for rational, selective, high yield reaction methods. The project will educate creative and skilled young scientists, which will include women and under represented minorities.
