Carboranes: Building Blocks for Materials and Ligand Developmen

Carborane anions are prized molecules due to their unique structure and bonding, as well as their anomalous stability and resistance to thermal and chemical decomposition. Since their discovery over half a century ago, they have been exploited as weakly coordinating anions stabilizing the most reactive cationic species known, but applications in catalysis by appending carborane anions as ligand substituents had never been attempted. We report a number of carborane-supported zwitterionic and anionic late transition metal complexes to serve as proof of concept for the application of anionic carborane ligand substituents in transition metal catalysis. The results from our studies confirm the anionic carborane is indeed inherently more stable than its isoelectronic neutral cousin, making it a suitable candidate for applications in catalysis. The donor properties of the 12 and 10 vertex anionic carboranes were probed to allow for the possibility of logical tuning of a given transition metal catalyst. Applications in catalysis and studies on the effect of charge as well as the development of a novel N-dicarbollide N-heterocyclic carbene are also reported. The work herein, should mitigate the development of novel single component zwitterionic and anionic transition metal complexes for applications including, but not limited to hydrogenation, dehydrogenation, alpha-olefin polymerization, as well as various cross coupling reactions. In addition to the aforementioned, the isolation of the first triazole radical anion is disclosed as well as the methodology to develop a library of potential isolable triazole radical anions for applications in functional materials.