Fortschritte bei Ammoniak‐Boran: verbessertes Recycling und Einsatz als Vorstufe für BN‐Einzelschichten

Anorganische Chemie 2011

“…Die Dehydrierung von Ammin‐Boran (AB) zu Polyboracyclen ist nach neuesten Erkenntnissen ein Schlüsselschritt, um leicht regenerierbare Systeme zur Wasserstoffspeicherung darzustellen. Dabei spielt die chemische Gasphasenabscheidung von AB unter Dehydrierung und die Bildung von Einzelschichten aus hexagonalem BN und dessen Hybriden mit Graphen eine bedeutende Rolle 1_27. Thermographische Untersuchungen des Ammin‐Borans H3NBH3 zeigen darüber hinaus eine stufenweise Kondensationsreaktion zu polymeren ‐[NH=BH]‐Verbindungen oberhalb von 130 °C unter gleichzeitiger Freisetzung von H2.…”

Paramagnetic Titanium(III) and Zirconium(III) Metallocene Complexes as Precatalysts for the Dehydrocoupling/Dehydrogenation of Amine–Boranes

“…[1] This development has been driven by potential applications with respect to hydrogen storage, [1,2] transfer hydrogenations and reductions of organic substrates, [3] and the preparation of new inorganic polymeric and solid-state materials. [4,5] A wide variety of catalyst systems have been developed that promote this reaction, [6][7][8][9][10] most of which are based on complexes of second-and third-row late transition metals. Mechanistic interest in these transformations has also led to the emergence of an interesting new area of coordination chemistry associated with amine-borane and aminoborane ligands.…”

“…[15] Chirik and co-workers suggested a similar mechanism, except that B À H bond activation was involved in the first step. [8] In contrast, on the basis of detailed kinetic studies, Manners, Lloyd-Jones, and co-workers proposed a two-stage catalytic cycle, with initial formation of the detected linear diborazane Me 2 NH-BH 2 -NMe 2 -BH 3 (5) after an N À H bond activation step, and subsequent on-metal ringclosing dehydrogenation to give 2. Once again, the proposed catalytic cycle was postulated to involve the interplay of Ti intermediates in the + 2 and + 4 oxidation states.…”