13871-09-5Relevant articles and documents
Probing the second dehydrogenation step in ammonia-borane dehydrocoupling: Characterization and reactivity of the key intermediate, B-(cyclotriborazanyl)amine-borane
Kalviri, Hassan A.,G?rtner, Felix,Ye, Gang,Korobkov, Ilia,Baker, R. Tom
, p. 618 - 624 (2015)
While thermolysis of ammonia-borane (AB) affords a mixture of aminoborane- and iminoborane oligomers, the most selective metal-based catalysts afford exclusively cyclic iminoborane trimer (borazine) and its B-N cross-linked oligomers (polyborazylene). This catalysed dehydrogenation sequence proceeds through a branched cyclic aminoborane oligomer assigned previously as trimeric B-(cyclodiborazanyl)amine-borane (BCDB). Herein we utilize multinuclear NMR spectroscopy and X-ray crystallography to show instead that this key intermediate is actually tetrameric B-(cyclotriborazanyl)amine-borane (BCTB) and a method is presented for its selective synthesis from AB. The reactivity of BCTB upon thermal treatment as well as catalytic dehydrogenation is studied and discussed with regard to facilitating the second dehydrogenation step in AB dehydrocoupling. This journal is
Catalytic Dehydrogenation of Amine-Boranes using Geminal Phosphino-Boranes
Boom, Devin H. A.,de Boed, Ewoud J. J.,Nicolas, Emmanuel,Nieger, Martin,Ehlers, Andreas W.,Jupp, Andrew R.,Slootweg, J. Chris
, p. 586 - 592 (2020/02/11)
The reaction of the intramolecular frustrated Lewis pair (FLP) tBu2PCH2BPh2 with the amine-boranes NH3·BH3 and Me2NH·BH3 leads to the formation of the corresponding FLP-H2/
Zirconium-Catalyzed Amine Borane Dehydrocoupling and Transfer Hydrogenation
Erickson, Karla A.,Stelmach, John P. W.,Mucha, Neil T.,Waterman, Rory
, p. 4693 - 4699 (2015/10/28)
κ5-(Me3SiNCH2CH2)2N(CH2CH2NSiMe2CH2)Zr (1) has been found to dehydrocouple amine borane substrates, RR′NHBH3 (R = R′ = Me; R = tBu, R′ = H; R = R′ = H), at low to moderate catalyst loadings (0.5-5 mol %) and good to excellent conversions, forming mainly borazine and borazane products. Other zirconium catalysts, (N3N)ZrX [(N3N) = N(CH2CH2NSiMe2CH2)3, X = NMe2 (2), Cl (3), and OtBu (4)], were found to exhibit comparable activities to that of 1. Compound 1 reacts with Me2NHBH3 to give (N3N)Zr(NMe2BH3) (5), which was structurally characterized and features an η2 B-H σ-bond amido borane ligand. Because 5 is unstable with respect to borane loss to form 2, rather than β-hydrogen elimination, and 2-4 do not exhibit X ligand loss during catalysis, dehydrogenation is hypothesized to proceed via an outer-sphere-type mechanism. This proposal is supported by the catalytic hydrogenation of alkenes by 2 using amine boranes as the sacrificial source of hydrogen.
