Frustrated Lewis Pairs: Principles and Some Recent Results
Frustrated Lewis Pairs: Principles and Some Recent Results
which will be delivered by Gerhard Erker from Westfälische Wilhelms-Universität Münster.
Lewis acids and bases usually undergo rapid neutralizing adduct formation. This can be prevented by steric bulk. In this case situations may be encountered where strong Lewis acids and bases are co-existent in solution, which may lead to new cooperative reactions.
The most prominent feature shown by phosphane/borane or amine/borane frustrated Lewis pairs (FLPs) is hydrogen activation. Many FLPs cleave the H2 molecule, which serves as the basis for the development of metal-free catalytic hydrogenations. However, FLPs undergo a variety of other remarkable reactions. They add to alkenes and alkynes, to carbonyl groups, including CO2, and to SO2. Intramolecular P/B FLPs have served as templates for the reduction of CO to the formyl borane stage and also react with typical small ligand molecules (isonitriles, carbon monoxide) in a way, which is reminiscent of their coordination behavior to transition metals. This will be demonstrated by the reaction of vicinal P/B FLPs with NO, resulting in the formation of a series of persistent FLPNO nitroxide radicals.
