Highly Active Iron Catalyst for Ammonia Borane Dehydrocoupling at Room Temperature

Abstract

The iron complex [FeH­(CO) (PNP)] (PNP = N­(CH2CH2PiPr2)2) is a highly active catalyst for ammonia borane dehydrocoupling at room temperature. Mainly linear polyaminoborane is obtained upon release of 1 equiv of H2. Mechanistic studies suggest that both hydrogen release and B–N coupling are metal-catalyzed and proceed via free aminoborane. Catalyst deactivation results from reaction with free BH3 that is formed by aminoborane rearrangement. Importantly, borane trapping with a simple amine allows for the observation of a TON that is unprecedented for a well-defined base metal catalyst.

Amine–Borane Dehydropolymerization: Challenges and Opportunities

“…This can be increased by recharging the catalyst system, which has been demonstrated for up to three cycles (ToN up to 1500) . Schneider has reported threefold improvements in ToN for H 3 B⋅NH 3 dehydropolymerization using Fe and Ru pincer systems upon addition of a catalytic amount of NMe 2 Et . The added amine prevents catalyst deactivation by BH 3 binding, produced from the rearrangement of 2 H 2 B=NH 2 to BH 3 ⋅THF and HB(NH 2 ) 2 …”

Elektronische Struktur und magnetische Anisotropie eines ungesättigten Cyclopentadienyleisen(I)‐Komplexes mit 15 Valenzelektronen

“…[43][44][45][46][47][48] [43] Unter Verwendung von 1 (5 Mol-%) wurde DMAB innerhalb von 7hvollständig zu Tetramethyl-1,3-diaza-2,4-diboretan (4)und Bis(dimethylamino)boran (5) umgesetzt. Hierbei zeigte sich, dass die Verbindung unter Normalbedingungen in C 6 D 6 -Lçsung nicht mit H 2 und N 2 reagiert.…”

“…[43][44][45][46][47][48] Dieses Ergebnis ist ein gutes Vorzeichen fürd ie zukünftige Entwicklung weiterer Anwendungen von 1 und von verwandten Cyclopentadienyleisen(I)-Komplexen in der Synthese und Katalyse. Als Folge davon zeigt 1 eine langsame Relaxation der Magnetisierung sowohl in An-als auch in Abwesenheit eines externen Magnetfeldes.D arüber hinaus katalysiert 1 die Dehydrierung von Dimethylamin-Boran, eine Reaktion, fürdie nur wenige Eisenkatalysatoren bekannt sind.…”

The Recycling of Spent Ammonia Borane with HBr/AlBr3 and Other HX/AlX3‐Based Schemes

“…Because of the low hydrogen release temperatures and the wide range of dehydrogenation possibilities, the compound has been studied extensively in recent years . Most research in this context has been devoted to the hydrogen release kinetics of AB in different phases . The hydrogen release from AB is accompanied by a heat release caused by the formation of strong B−N bonds leading to borazine or polymerized BNH x ‐waste products like polyaminoborane and heavily cross‐linked polyborazylene (PB).…”