1838-13-7Relevant articles and documents
Polymer-graphene hybrid stabilized ruthenium nanocatalysts for the dimethylamine-borane dehydrogenation at ambient conditions
?en, Betül,Aygün, Ay?enur,?avk, Aysun,Duman, Sibel,Calimli, Mehmet Harbi,Bulut, Ela,?en, Fatih
, p. 578 - 583 (2019)
In this work, we reported a new catalyst consistent of graphene oxide (GO) – poly(N-vinyl-2-pyrrolidone) (PVP) hybrid supported ruthenium nanoparticles and called as Ru@GO-PVP. The GO-coupled PVP nanosheets were prepared with a new and straightforward pathway. The prepared Ru@GO-PVP nanocatalysts were characterized using some advanced analytic measurements such as XPS (X-ray photoelectron spectroscopy), XRD (X-ray diffraction), TEM/HRTEM (Transmission electron microscopy/high resolution transmission electron microscopy), Raman and ICP (Inductively coupled plasma). The mean particle size of the catalyst was found to be 2.09 nm, and this catalyst having small particle size showed one of the highest catalytic activities with a very high TOF value of 896.54 h?1 in dehydrogenation of DMAB at room temperature. Therefore, the proposed hybrid and supported catalyst offer a new pathway to enhance the catalytic dehydrogenation of DMAB greatly, and this study presents a universal and powerful technique for such applications.
Dehydropolymerisation of Methylamine Borane and an N-Substituted Primary Amine Borane Using a PNP Fe Catalyst
Anke, Felix,Boye, Susanne,Spannenberg, Anke,Lederer, Albena,Heller, Detlef,Beweries, Torsten
, p. 7889 - 7899 (2020)
Dehydropolymerisation of methylamine borane (H3B?NMeH2) using the well-known iron amido complex [(PNP)Fe(H)(CO)] (PNP=N(CH2CH2PiPr2)2) (1) gives poly(aminoborane)s by a chain-growth mechanism. In toluene, rapid dehydrogenation of H3B?NMeH2 following first-order behaviour as a limiting case of a more general underlying Michaelis–Menten kinetics is observed, forming aminoborane H2B=NMeH, which selectively couples to give high-molecular-weight poly(aminoborane)s (H2BNMeH)n and only traces of borazine (HBNMe)3 by depolymerisation after full conversion. Based on a series of comparative experiments using structurally related Fe catalysts and dimethylamine borane (H3B?NMe2H) polymer formation is proposed to occur by nucleophilic chain growth as reported earlier computationally and experimentally. A silyl functionalised primary borane H3B?N(CH2SiMe3)H2 was studied in homo- and co-dehydropolymerisation reactions to give the first examples for Si containing poly(aminoborane)s.
P-C-Activated Bimetallic Rhodium Xantphos Complexes: Formation and Catalytic Dehydrocoupling of Amine-Boranes
Johnson, Heather C.,Weller, Andrew S.
, p. 10173 - 10177 (2015)
{Rh(xantphos)}-based phosphido dimers form by P-C activation of xantphos (4,5-bis(diphenylphosphino)-9,9-dimethylxanthene) in the presence of amine-boranes. These dimers are active dehydrocoupling catalysts, forming polymeric [H2BNMeH]n from H3B·NMeH2 and dimeric [H2BNMe2]2 from H3B·NMe2H at low catalyst loadings (0.1 mol %). Mechanistic investigations support a dimeric active species, suggesting that bimetallic catalysis may be possible in amine-borane dehydropolymerization.
Catalytic dehydrogenation of dimethylamine borane by group 4 metallocene alkyne complexes and homoleptic amido compounds
Beweries, Torsten,Hansen, Sven,Kessler, Monty,Klahn, Marcus,Rosenthal, Uwe
, p. 7689 - 7692 (2011)
Dehydrogenation of Me2NH·BH3 (1) by group 4 metallocene alkyne complexes of the type Cp2M(L)(η2- Me3SiC2SiMe3) [Cp = η5- cyclopentadienyl; M = Ti, no L (2Ti); M = Zr, L = pyridine (2Zr)] and group 4 metal amido complexes of the type M(NMe2)4 [M = Ti (8Ti), Zr (8Zr)] is presented.
Displacement of diborane from pentaborane(9) by strong molecular bases
Burg, Anton B.
, p. 1448 - 1450 (1973)
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Monodisperse Pt nanoparticles assembled on reduced graphene oxide: Highly efficient and reusable catalyst for methanol oxidation and dehydrocoupling of dimethylamine-borane (DMAB)
Yildiz, Yunus,Erken, Esma,Pamuk, Handan,Sert, Hakan,?en, Fatih
, p. 5951 - 5958 (2016)
Herein, monodisperse platinum (0) nanocatalyst assembled on reduced graphene oxide (Pt(0)@RGO) was easily and reproducibly prepared by the double solvent reduction method at room temperature. Pt(0)@RGO was characterized by X-ray diffraction (XRD), X-ray photoelectron microscopy (XPS) and transmission electron microscopy (TEM) measurements that verify the formation of monodisperse Pt (0) nanoparticles on RGO. The catalytic and electrocatalytic performances of Pt(0)@RGO in terms of activity, isolability and reusability were investigated for both methanol oxidation and the dehydrocoupling of dimethylamine-borane (DMAB) in which Pt(0)@RGO was found to be highly active and reusable heterogeneous catalyst even at room temperature. The prepared nanoparticles can also electrocatalyze methanol oxidation with very high electrochemical activities (5.64 A/cm2 at 0.58 V for methanol,). The activation energy (Ea), activation enthalpy (ΔH#), and activation entropy (ΔS#) for DMAB dehydrogenation were calculated to be 59.33 kJ mol-1, 56.79 kJ mol-1 and -151.68 J mol-1K-1, respectively. The exceptional stability of new Pt(0)@RGO nanoparticles towards agglomeration, leaching and CO poisoning allow these particles to be recycled and reused in the catalysis of DMAB dehydrogenation and methanol oxidation. After four subsequent reaction and recovery cycles, Pt(0)@RGO retained ≥75% activity towards the complete dehydrogenation of DMAB.
A Highly Active Bidentate Magnesium Catalyst for Amine-Borane Dehydrocoupling: Kinetic and Mechanistic Studies
Ried, Alexander C. A.,Taylor, Laurence J.,Geer, Ana M.,Williams, Huw E. L.,Lewis, William,Blake, Alexander J.,Kays, Deborah L.
, p. 6840 - 6846 (2019)
A magnesium complex (1) featuring a bidentate aminopyridinato ligand is a remarkably selective catalyst for the dehydrocoupling of amine-boranes. This reaction proceeds to completion with low catalyst loadings (1 mol %) under mild conditions (60 °C), exceeding previously reported s-block systems in terms of selectivity, rate, and turnover number (TON). Mechanistic studies by in situ NMR analysis reveals the reaction to be first order in both catalyst and substrate. A reaction mechanism is proposed to account for these findings, with the high TON of the catalyst attributed to the bidentate nature of the ligand, which allows for reversible deprotonation of the substrate and regeneration of 1 as a stable resting state.
Mechanistic insights into dehydrocoupling of amine boranes using dinuclear zirconocene complexes
Al Hamwi, Hanan,Beweries, Torsten,Drexler, Hans-Joachim,Heller, Detlef,Jannsen, Nora,Lindenau, Kevin,Neymeyr, Klaus,Rei?, Fabian,Rippke, Mirko,Sawall, Mathias,Selle, Carmen,Spannenberg, Anke
supporting information, p. 4034 - 4050 (2021/07/06)
Catalytic dehydrocoupling of H3B·NMe2H using the in situ system Cp2Zr(Cl)(μ-Me3SiC3SiMe3)Zr(Cl)Cp2 (1)/MeLi was studied as a model for previously reported dehydropolymerisation of H3B·NMeH2. NMR and UV-vis spectroscopic monitoring of the precatalyst activation sequence as well as a series of stoichiometric experiments showed that formation of a zirconocene dimethyl complex (2) is not relevant for activation of the precatalyst. Instead, deprotonation of H3B·NMe2H and reaction of thus formed Li[NMe2BH3] is proposed to result in the formation of Zr amidoborane and hydride species. DFT analysis using such complexes as active species showed a pathway for formation of H2 and H2BNMe2. 1H NMR spectroscopic monitoring and stoichiometric control experiments revealed the formation of unusual diamagnetic dinuclear complexes Cp2Zr(C2SiMe3)(μ-R)ZrCp2 (R = CH2SiMe3, 7; R = H, 9) formed by activation of the allenediide unit of the precatalyst 1. Such species can be regarded as rare single-component catalysts for the dehydrocoupling of amine boranes. This journal is
Bifunctional activation of amine-boranes by the W/Pd bimetallic analogs of “frustrated Lewis pairs”
Osipova, Elena S.,Gulyaeva, Ekaterina S.,Gutsul, Evgenii I.,Kirkina, Vladislava A.,Pavlov, Alexander A.,Nelyubina, Yulia V.,Rossin, Andrea,Peruzzini, Maurizio,Epstein, Lina M.,Belkova, Natalia V.,Filippov, Oleg A.,Shubina, Elena S.
, p. 3682 - 3692 (2021/03/26)
The reaction between basic [(PCP)Pd(H)] (PCP = 2,6-(CH2P(t-C4H9)2)2C6H4) and acidic [LWH(CO)3] (L = Cp (1a), Tp (1b); Cp = η5-cyclopentadienyl, Tp = κ3-hydridotris(pyrazolyl)borate) leads to the formation of bimolecular complexes [LW(CO)2(μ-CO)?Pd(PCP)] (4a,4b), which catalyze amine-borane (Me2NHBH3tBuNH2BH3) dehydrogenation. The combination of variable-temperature (1H,31P{1H},11B NMR and IR) spectroscopies and computational (ωB97XD/def2-TZVP) studies reveal the formation of an η1-borane complex [(PCP)Pd(Me2NHBH3)]+[LW(CO3)]?(5) in the first step, where a BH bond strongly binds palladium and an amine group is hydrogen-bonded to tungsten. The subsequent intracomplex proton transfer is the rate-determining step, followed by an almost barrierless hydride transfer. Bimetallic species4are easily regenerated through hydrogen evolution in the reaction between two hydrides.
