This project in the Inorganic, Bioinorganic and Organometallic Chemistry Program deals with the synthesis and exploitation of weakly coordinating anions. These are negatively charged ions which are designed to have little tendency to form bonds either to metal atoms or to positively charged ions in general. The need for new anions which approach the ideal of a non-coordinating anion is general throughout chemistry, and wide application in synthetic chemistry and in mechanistic studies is envisioned. The main focus of the project will be the pseudo-icosahedral carborane anion B11CH12- and its derivatives, which will be investigated as counterions for reactive cations. Substitution at both the C-H and B-H bonds will be used to increase the size of the anion, lower its nucleophilicity, and lower its tendency towards oxidation. The new weakly-coordinating anions are expected to enable the structural characterization of long sought after ions such as the silicenium ion, the formation of complexes of very weak donors (e.g. xenon, hydrocarbons, fluorocarbons), the improvement of cationic homogeneous catalysts and an expansion of scope and diversity of Lewis acid and electrophile-promoted chemistry.
