Advances with Ammonia-Borane: Improved Recycling and Use as a Precursor to Atomically Thin BN Films

摘要

mine-boranes, exemplified by ammonia-borane (AB), H3N·BH3, represent some of the simplest and best-known inorganic molecules. Over the past decade these compounds have attracted considerable attention as portable hydrogen storage materials, due in the main part to their high gravimetric hydrogen contents (ca. 20% by weight for AB). This has motivated the development of new synthetic methods for convenient hydrogen release, and a variety of highly active catalysts that function under mild conditions are now known. These procedures have recently been adapted to allow the preparation of new polymeric materials. For example, polyaminoboranes, (RNH-BH2)_n have been prepared by catalytic dehydrogenation of primary amine-bor-anes, such as MeNH2-BH3. Amine-boranes have also been widely used as reducing agents, including for the preparation of metal nanoparticles, and in hydrogen-transfer reactions involving organic substrates. Moreover, as a consequence of the expanded interest in hydrogen release, the field of amine-borane coordination chemistry is now under active development.'4' Discoveries in this new area promise improved fundamental understanding of the activation and transformation of these fascinating molecules at transition-metal centers, processes that appear central to both their dehydrogenation and polymerization chemistries.