B-N lightweight inorganic hydrides dehydrogenation mediated by transition metal complexes: a combined experimental-theoretical approach

Lightweight inorganic hydrides are at the forefront of contemporary chemical hydrogen storage research. They are easy-to-handle and thermally stable compounds with relatively high hydrogen content. Among the most studied materials belonging to this class there are ammonia borane (NH3?BH3, AB, 19.3 % H wt.) and borohydrides (BH4-, 18.3 % max. H wt). In the last decade, homogeneously catalyzed AB and BH4- dehydrogenation has become increasingly popular; H2 evolution is mediated by organometallics of d-block elements. In this lecture, a selection of examples will be presented, with a particular focus on the H2 generation mechanism as a result of initial dihydrogen bonding (DHB) interaction between hydridic and protonic H atoms present in the reaction environment. The combination of experiment (NMR and IR spectroscopic studies at variable temperature, kinetic rate measurements) and theory (DFT studies of the reaction mechanism and identification of intermediates) is a particularly useful approach to get insights in this field.