New Molecular Scaffolds for Frustrated Lewis Pair Systems

The goal of this research is to synthesize new bulky Lewis acid and base molecules and incorporate them into frustrated Lewis pair systems (FLPs). FLP systems consist of a bulky Lewis acid combined with a bulky Lewis base. Due to steric hindrance, classical bonding interactions cannot occur. Instead an energy potential is created between the frustrated molecules which is capable of activating unreactive small molecules. FLPs have received a great deal of attention in recent years for their ability to activate small molecules like carbon dioxide and perform the first examples of metal-free catalytic hydrogenation. By creating a Lewis acidic borane based on a carborane, we aim to demonstrate that carboranes are suitable structural components for construction of FLPs. Carboranes have a similar size to the aryl rings used in existing FLPs, but project in three dimensions, making them bulkier and possibly superior to phenyl rings as pendant groups for FLP acids. Once produced, the new boranes will be evaluated on their ability to participate in FLP chemistry, and on their potential in catalyzing metal-free hydrogenation and activation of small molecules. If the acid shows FLP activity a new bulky Lewis base will then be synthesized by linking a phosphine group to a carborane cage similar to the acid cage. Once produced, the phospine will be combined with the Lewis acidic borane and evaluated on its potential in hydrogen activation. These new compounds may have potential applications in catalysis, green chemistry, carbon dioxide capture and hydrogen storage