27073-27-4Relevant articles and documents
The Simplest Amino-borane H2B=NH2 Trapped on a Rhodium Dimer: Pre-Catalysts for Amine-Borane Dehydropolymerization
Kumar, Amit,Beattie, Nicholas A.,Pike, Sebastian D.,Macgregor, Stuart A.,Weller, Andrew S.
, p. 6651 - 6656 (2016)
The μ-amino-borane complexes [Rh2(LR)2(μ-H)(μ-H2B=NHR′)][BArF4] (LR=R2P(CH2)3PR2; R=Ph, iPr; R′=H, Me) form by addition of H3BNMeR′H2 to [Rh(LR)(η6-C6H5F)][BArF4]. DFT calculations demonstrate that the amino-borane interacts with the Rh centers through strong Rh-H and Rh-B interactions. Mechanistic investigations show that these dimers can form by a boronium-mediated route, and are pre-catalysts for amine-borane dehydropolymerization, suggesting a possible role for bimetallic motifs in catalysis. Bridges of boron: Mechanistic investigations show that rhodium dimers bridged by amino-borane can form by a boronium-mediated route starting from amine-borane. These types of complexes are pre-catalysts for amine-borane dehydropolymerization, suggesting a possible role for bimetallic motifs in catalysis.
Catalytic redistribution and polymerization of diborazanes: Unexpected observation of metal-free hydrogen transfer between aminoboranes and amine-boranes
Robertson, Alasdair P. M.,Leitao, Erin M.,Manners, Ian
, p. 19322 - 19325 (2012/01/13)
Ir-catalyzed (20 °C) or thermal (70 °C) dehydrocoupling of the linear diborazane MeNH2-BH2-NHMe-BH3 led to the formation of poly- or oligoaminoboranes [MeNH-BH2]x (x = 3 to >1000) via an initial redistribution process that forms MeNH 2?BH3 and also transient MeNH=BH2, which exists in the predominantly metal-bound and free forms, respectively. Studies of analogous chemistry led to the discovery of metal-free hydrogenation of the B=N bond in the "model" aminoborane iPr2N=BH2 to give iPr2NH?BH3 upon treatment with the diborazane Me3N-BH2-NHMe-BH3 or amine-boranes RR′NH?BH3 (R, R′ = H or Me).
Dehydrocoupling reactions of borane-secondary and -primary amine adducts catalyzed by group-6 carbonyl complexes: Formation of aminoboranes and borazines
Kawano, Yasuro,Uruichi, Mikio,Shimoi, Mamoru,Taki, Seitaro,Kawaguchi, Takayuki,Kakizawa, Taeko,Ogino, Hiroshi
, p. 14946 - 14957 (2010/01/16)
Photoirradiation of a solution of BH3·NHR2 (1a: R = Me, 1b: R = 1/2C4H8, 1c: R = 1/2C 5H10, 1f: R = Et) containing a catalytic amount of a group-6 metal carbonyl complex, [M(CO)6] (M = Cr, Mo, W), led to dehydrogenative B-N covalent bond formation to produce aminoborane dimers, [BH2NR2]2 (2a-c, f), in high yield. During these reactions a borane σ complex, [M(CO)5(η1- BH3·NHR2)] (3), was detected by NMR spectroscopy. Similar catalytic dehydrogenation of bulkier amineboranes, BH 3·NHiPr2 (1d) and BH3· NHCy2 (1e, Cy = cyclo-C6H11), afforded monomeric products BH2=NR2 (4d, e). The reaction mechanism of the dehydrocoupling was investigated by DFT calculations. On the basis of the computational study, we propose that the catalytic dehydrogenation reactions proceed via an intramolecular pathway and that the active catalyst is [Cr(CO)4]. The reaction follows a stepwise mechanism involving NH and BH activation. Dehydrocoupling of borane-primary amine adducts BH 3·NH2R (1g: R = Me, 1h: R = Et, 1i: R = tBu) gave borazine derivatives [BHNR]3 (5g-i).
