27073-27-4

Upstream product

• 1722-33-4 methylamine-borane 
• 1349095-84-6 Me₃N-BH₂-NHMe-BH₃ 
• 22092-92-8 diisopropopylaminoborane 
• 1314251-72-3 MeNH₂-BH₂-NHMe-BH₃ 
• 199620-14-9 chromium⁽⁰⁾ hexacarbonyl 

Downstream Products

• 21127-94-6 1-methylborazine 
• 23208-28-8 1,3-dimethylborazine 
• 6569-51-3 borazine 
• 1004-35-9 1,3,5-trimethyl-cyclotriborazane 
• 6601-31-6 (methylamino)dihydroborane 
• 19287-45-7 diborane 

Relevant academic research and scientific papers

The Simplest Amino-borane H2B=NH2 Trapped on a Rhodium Dimer: Pre-Catalysts for Amine-Borane Dehydropolymerization

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.

Mechanisms of the thermal and catalytic redistributions, oligomerizations, and polymerizations of linear diborazanes

Linear diborazanes R3N-BH2-NR2-BH 3 (R = alkyl or H) are often implicated as key intermediates in the dehydrocoupling/dehydrogenation of amine-boranes to form oligo- and polyaminoboranes. Here we report detailed studies of the reactivity of three related examples: Me3N-BH2-NMe2-BH3 (1), Me3N-BH2-NHMe-BH3 (2), and MeNH 2-BH2-NHMe-BH3 (3). The mechanisms of the thermal and catalytic redistributions of 1 were investigated in depth using temporal-concentration studies, deuterium labeling, and DFT calculations. The results indicated that, although the products formed under both thermal and catalytic regimes are identical (Me3N·BH3 (8) and [Me2N-BH2]2 (9a)), the mechanisms of their formation differ significantly. The thermal pathway was found to involve the dissociation of the terminal amine to form [H2B(μ-H)(μ-NMe 2)BH2] (5) and NMe3 as intermediates, with the former operating as a catalyst and accelerating the redistribution of 1. Intermediate 5 was then transformed to amine-borane 8 and the cyclic diborazane 9a by two different mechanisms. In contrast, under catalytic conditions (0.3-2 mol % IrH2POCOP (POCOP = κ3-1,3-(OPtBu 2)2C6H3)), 8 was found to inhibit the redistribution of 1 by coordination to the Ir-center. Furthermore, the catalytic pathway involved direct formation of 8 and Me2Ni - BH2 (9b), which spontaneously dimerizes to give 9a, with the absence of 5 and BH3 as intermediates. The mechanisms elucidated for 1 are also likely to be applicable to other diborazanes, for example, 2 and 3, for which detailed mechanistic studies are impaired by complex post-redistribution chemistry. This includes both metal-free and metal-mediated oligomerization of MeNHi - BH2 (10) to form oligoaminoborane [MeNH-BH 2]x (11) or polyaminoborane [MeNH-BH2] n (16) following the initial redistribution reaction.

Catalytic redistribution and polymerization of diborazanes: Unexpected observation of metal-free hydrogen transfer between aminoboranes and amine-boranes

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).

Catching the first oligomerization event in the catalytic formation of polyaminoboranes: H3B·NMeHBH2·NMeH 2 bound to iridium

We report the first insertion step at a metal center for the catalytic dehydropolymerization of H3B·NMeH2 to form the simplest oligomeric species, H3B·NMeHBH2· NMeH2, by the addition of 1 equiv of H3B·NMeH 2 to [Ir(PCy3)2(H)2(η 2-H3B·NMeH2)][BArF 4] to give [Ir(PCy3)2(H)2(η 2-H3B·NMeHBH2·NMeH 2)][BArF4]. This reaction is also catalytic for the formation of the free linear diborazane, but this is best obtained by an alternative stoichiometric synthesis.

Dehydrocoupling reactions of borane-secondary and -primary amine adducts catalyzed by group-6 carbonyl complexes: Formation of aminoboranes and borazines

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).