1004-35-9Relevant academic research and scientific papers
Dehydrocoupling reactions of secondary and primary amine-borane adducts catalyzed by half-sandwich carbonyl complexes, [CpMn(CO)3], [(η6-C6H6)Cr(CO)3], and [CpV(CO)4]
Kakizawa, Taeko,Kawano, Yasuro,Naganeyama, Kohsuke,Shimoi, Mamoru
, p. 171 - 173 (2011)
Dehydrocoupling reactions of amineborane adducts catalyzed by half-sandwich carbonyl complexes are described. Secondary amine-borane adducts released H2 with catalytic action of [CpMn(CO)3] (Cp: η5-C5H5/su
Molecular Quadrupole Moments, Magnetic Anisotropies, and Charge Distributions of Borazine, B-Trichloroborazine, N-Trimethylborazine, and B-Trichloro-N-trimethylborazine. Comparison with Benzene and Its Derivatives.
Dennis, Gary R.,Ritchie, Geoffrey L. D.
, p. 8403 - 8409 (1993)
Measurements of the dilute-solution molar Kerr constants, field-gradient birefringence constants, and Cotton-Mouton constants of borazine and three substituted borazines as solutes in cyclohexane or carbon tetrachloride at 25 deg C are reported.The observations yield the first direct experimental values of the effective polarizability anisotropies, electric quadrupole moments, and magnetic anisotropies, which are important descriptors of the molecular charge distributions.A comparison of the results for borazine with literature data for benzene shows that all three properties have the same signs in the two species but that all are considerably smaller in magnitude in borazine than in benzene.An analysis of the magnetizabilities indicates that the extent of electron delocalization in borazine is only about one-third of that in benzene, a conclusion which is consistent with a range of other evidence.
Photoactivated, iron-catalyzed dehydrocoupling of amine-borane adducts: Formation of boron-nitrogen oligomers and polymers
Vance, James R.,Robertson, Alasdair P. M.,Lee, Kajin,Manners, Ian
, p. 4099 - 4103 (2011)
Dehydrogenation chemistry with iron: The first examples of efficient iron-catalyzed dehydrocoupling/dehydrogenation of amine-boranes at ambient temperature have been reported. In the case of the primary amine-borane adduct MeNH2·BH3, both the polymer and/or N-alkyl borazine can be obtained (see scheme; 1=[{CpFe(CO)2}2]). Copyright
Possible intermediates in the formation of 1,3,5-trimethylborazine
Beachley Jr.
, p. 701 - 703 (1968)
The 110° pyrolysis of H2B(NH2CH3)2+Cl -, H2CH3NBH2NHCH3BH2NH 2CH3+Cl-, and mixtures of (H2BNHCH3)3 and CH3NH3Cl give H3B3N3(CH3)3, CH3NH3Cl, and H2. The intermediates in the formation of the borazine ring have been investigated by studying the conversion of H2B(NH2CH3)2+Cl - to H3B3N3(CH3)3 in a mass spectrometer and by attempting to prepare possible intermediates. The current experimental evidence suggests that an initial intermediate is a linear, six-membered boron-nitrogen chain. Then, an intramolecular dehydrogenation ring-closure reaction between the ends of the chain leads to a species analogous to cyclohexenes. The more stable borazine ring is then formed from the cyclohexene type of species by the rapid loss of H2.
Rhodium-catalyzed formation of boron-nitrogen bonds: A mild route to cyclic aminoboranes and borazines
Jaska,Temple,Lough,Manners
, p. 962 - 963 (2001)
Secondary amine-borane adducts R2NH·BH3, which are stable to H2 elimination below 100 °C, undergo efficient catalytic dehydrocoupling at 25-45 °C in the presence of RhI or RhIII complexes to quantitatively form cyclic aminoboranes [NR2-BH2]2 (1: R = Me or 2: cyclo-C4H8); under similarly mild conditions, the analogous adducts NH3·BH3 and MeNH2·BH3 yield borazines [RN-BH]3 (3: R-H or 4: R = Me) in yields limited by intermolecular coupling reactions.
Catalytic dehydrocoupling of amine-borane adducts to form aminoboranes and borazines
Jaska, Cory A.,Temple, Karen,Lough, Alan J.,Manners, Ian
, p. 733 - 736 (2004)
A mild, catalytic dehydrocoupling route to aminoboranes and borazine derivatives from either primary or secondary amine-borane adducts has been developed using late transition metal complexes as precatalysts. The dehydrocoupling of Me2NH·BHsub
Bis-BN cyclohexane: A remarkably kinetically stable chemical hydrogen storage material
Chen, Gang,Zakharov, Lev N.,Bowden, Mark E.,Karkamkar, Abhijeet J.,Whittemore, Sean M.,Garner, Edward B.,Mikulas, Tanya C.,Dixon, David A.,Autrey, Tom,Liu, Shih-Yuan
, p. 134 - 137 (2015)
A critical component for the successful development of fuel cell applications is hydrogen storage. For back-up power applications, where long storage periods under extreme temperatures are expected, the thermal stability of the storage material is particularly important. Here, we describe the development of an unusually kinetically stable chemical hydrogen storage material with a H2 storage capacity of 4.7 wt%. The compound, which is the first reported parental BN isostere of cyclohexane featuring two BN units, is thermally stable up to 150 °C both in solution and as a neat material. Yet, it can be activated to rapidly desorb H2 at room temperature in the presence of a catalyst without releasing other detectable volatile contaminants. We also disclose the isolation and characterization of two cage compounds with S4 symmetry from the H2 desorption reactions.
Transition metal-catalyzed formation of boron-nitrogen bonds: Catalytic dehydrocoupling of amine-borane adducts to form aminoboranes and borazines
Jaska, Cory A.,Temple, Karen,Lough, Alan J.,Manners, Ian
, p. 9424 - 9434 (2003)
A mild, catalytic dehydrocoupling route to aminoboranes and borazine derivatives from either primary or secondary amine-borane adducts has been developed using late transition metal complexes as precatalysts. The adduct Me2NH·BH3 thermally eliminates hydrogen at 130 °C in the condensed phase to afford [Me2N-BH2]2 (1). Evidence for an intermolecular process, rather than an intramolecular reaction to form Me2N=BH2 as an intermediate, was forthcoming from "hot tube" experiments where no appreciable dehydrocoupling of gaseous Me2NH·BH3 was detected in the range 150-450 °C. The dehydrocoupling of Me2NH·BH3 was found to be catalyzed by 0.5 mol % [Rh(1,5-cod)(μ-Cl)]2 in solution at 25 °C to give 1 quantitatively after ca. 8 h. The rate of dehydrocoupling was significantly enhanced if the temperature was raised or if the catalyst loading was increased. The catalytic activity of various other transition metal complexes (Ir, Ru, Pd) for the dehydrocoupling of Me2NH·BH3 was also demonstrated. This new catalytic method was extended to other secondary adducts RR′NH·BH3 which afforded the dimeric species [(1,4-C4H8)N-BH2]2 (2) and [PhCH2(Me)N-BH2]2 (3) or the monomeric aminoborane iPr2N=BH2 (4) under mild conditions. A new synthetic approach to the linear compounds R2NH-BH2-NR2-BH3 (5: R = Me; 6: R = 1,4-C4H8) was developed and subsequent catalytic dehydrocoupling of these species yielded the cyclics 1 and 2. The species 5 and 6 are postulated to be intermediates in the formation of 1 and 2 directly from the catalytic dehydrocoupling of the adducts R2NH·BH3. The catalytic dehydrocoupling of NH3·BH3, MeNH2· BH3, and PhNH2·BH3 at 45 °C to give the borazine derivatives [RN-BH]3 (10: R = H; 11: R = Me; 12: R = Ph) was demonstrated. TEM analysis of the contents of the reaction solution for the [Rh(1,5-cod)(μ-Cl)]2 catalyzed dehydrocoupling of Me2NH·BH3 together with Hg poisoning experiments suggested a heterogeneous catalytic process involving Rh(0) colloids.
Mechanistic studies of the dehydrocoupling and dehydropolymerization of amine-boranes using a [Rh(Xantphos)]+ catalyst
Johnson, Heather C.,Leitao, Erin M.,Whittell, George R.,Manners, Ian,Lloyd-Jones, Guy C.,Weller, Andrew S.
, p. 9078 - 9093 (2014)
A detailed catalytic, stoichiometric, and mechanistic study on the dehydrocoupling of H3B·NMe2H and dehydropolymerization of H3B·NMeH2 using the [Rh(Xantphos)]+ fragment is reported. At 0.2 mol % catalyst loadings, dehydrocoupling produces dimeric [H2B-NMe2]2 and poly(methylaminoborane) (Mn = 22 700 g mol-1, PDI = 2.1), respectively. The stoichiometric and catalytic kinetic data obtained suggest that similar mechanisms operate for both substrates, in which a key feature is an induction period that generates the active catalyst, proposed to be a Rh-amido-borane, that reversibly binds additional amine-borane so that saturation kinetics (Michaelis-Menten type steady-state approximation) operate during catalysis. B-N bond formation (with H3B·NMeH 2) or elimination of amino-borane (with H3B· NMe2H) follows, in which N-H activation is proposed to be turnover limiting (KIE = 2.1 ± 0.2), with suggested mechanisms that only differ in that B-N bond formation (and the resulting propagation of a polymer chain) is favored for H3B·NMeH2 but not H 3B·NMe2H. Importantly, for the dehydropolymerization of H3B·NMeH2, polymer formation follows a chain growth process from the metal (relatively high degrees of polymerization at low conversions, increased catalyst loadings lead to lower-molecular-weight polymer), which is not living, and control of polymer molecular weight can be also achieved by using H2 (Mn = 2 800 g mol-1, PDI = 1.8) or THF solvent (Mn = 52 200 g mol-1, PDI = 1.4). Hydrogen is suggested to act as a chain transfer agent in a similar way to the polymerization of ethene, leading to low-molecular-weight polymer, while THF acts to attenuate chain transfer and accordingly longer polymer chains are formed. In situ studies on the likely active species present data that support a Rh-amido-borane intermediate as the active catalyst. An alternative Rh(III) hydrido-boryl complex, which has been independently synthesized and structurally characterized, is discounted as an intermediate by kinetic studies. A mechanism for dehydropolymerization is suggested in which the putative amido-borane species dehydrogenates an additional H3B·NMeH2 to form the real monomer amino-borane H2B=NMeH that undergoes insertion into the Rh-amido bond to propagate the growing polymer chain from the metal. Such a process is directly analogous to the chain growth mechanism for single-site olefin polymerization.
Method of manufacturing Alkylborazine-N
-
Paragraph 0052; 0053; 0056; 0057; 0060, (2017/04/05)
PROBLEM TO BE SOLVED: To provide a method for producing a borazine compound, with which the reaction yield and the purity of the end product are further improved.SOLUTION: A reaction is conducted by supplying raw material slurry to be added including one of a metal borohydride or an amine salt represented by (RNH)X (in formula, R represents a hydrogen atom, an alkyl group, or a cycloalkyl group, X represents a sulfate group or a halogen atom, and n is 1 or 2) and a solvent to an initially prepared liquid including the other of the metal borohydride and the amine salt and the solvent in a reaction vessel via a feed nozzle 120a. Here, a tip of the feed nozzle is located at a position within a range, corresponding to a distance Lfrom the liquid level of the reaction liquid, of 30-100% of a maximum distance Lin the vertical direction from the liquid level to the inside upper face of the reaction vessel, and the tip of the feed nozzle is located in a region with a similarity ratio of a horizontal plane including the tip of the feed nozzle to the horizontal cross-sectional shape of the reaction vessel of 0-0.8 when the center of gravity of the cross-sectional shape is set to be a center of similitude.
