- Infrared Spectrum of Dichloroborane Produced by CO2 Laser Enhanced Reaction
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Infrared spectra of HBCl2 and DBCl2 produced by a TEA CO2 laser enhanced reaction of BCl3 and H2/D2 have been observed by an FT-IR spectrometer at a resolution of 0.12 cm-1.A detailed analysis has been carried out for the ν1 band of
- Lee, Kuk-Haeng,Takeo, Harutoshi,Kondo, Shigeo,Matsumura, Chi
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- Gaseous boroxine: Mechanism of reaction with boron trihalides
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Low-pressure reactions of gaseous boroxine (H3B3O3) with boron trihalides to produce dihaloborane and boric oxide have been studied by infrared absorption techniques. Kinetic data indicate that the reaction is close to first order in boroxine pressure. The pressure dependence of BF3 in the BF3-H3B3O3 reaction is close to zero order for BF3 pressures above 10 mm but tends toward a higher order at lower pressures. Reactions are accelerated in cells coated with B2O3(s). Reaction rates increase in the order BF3 3 3. Spectra of products of the reaction of 10B-labeled compounds show that the boron atoms in H3B3O3 appear in HBX2 and the boron atom in BX3 appears in B2O3(s). A surface mechanism which accounts for the 10B distribution in the products is proposed.
- Nadler,Porter, Richard F.
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- Preparation and HeI Photoelectron Spectra of the Dihaloboranes, HBX2 (X= Cl and Br)
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The unstable dihaloboranes, HBCl2 and HBBr2, have been generated in the gas phase from the virtually quantitative reaction of gaseous BX3 with solid NaBH4 at ca. 250 deg C.HeI photoelectron spectra have been obtained and interpreted with the aid of ab ini
- Frost, D.C.,Kirby, C.,McDowell, C.A.,Westwood, N.P.C.
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- Hydroboration with haloborane/trialkylsilane mixtures
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Trialkylsilanes or dialkylsilanes react rapidly with boron trichloride in the absence of ethereal solvents or other nucleophiles to form unsolvated dichloroborane. If no substrate is present, dichloroborane disproportionates to trichloroborane and two geo
- Soundararajan, Raman,Matteson, Donald S.
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p. 4157 - 4166
(2008/10/09)
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- Reactions of the diboron tetrahalides B2Cl4 and B2Br4 with B5H9: Preparation and properties of the (dihaloboryl)pentaborane derivatives 1-BX2B5H8, (X = Br, Cl, F, OCH3, t-Bu, H) and synthesis of (BCl2)3B5H6
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The reactions of B2Cl4 with excess B5H9 yield 1-BCl2B5H8 (73%) while those of B2Br4 generate 1-BBr2B5H8 (80%). Ligand exchange of 1-BCl2B5H8 with excess BBr3 forms 1-BBr2B5H8 (86%), that with Hg(CF3)2 results in 1-BF2B5H8 (96%), that with CH3OH generates 1-B(OCH3)2B5H8 (46%), and that with Li(t-Bu) prepares B(t-Bu)(Cl)B5H8 (23%) and B(t-Bu)2B5H8 (20%). The relative thermal stabilities of these products are BF2B5H8 > BCl2B5H8 > BBr2B5H8 > B(OCH3)2B5H8 > B(t-Bu)2B5H8. All of these BX2B5H8 compounds (X = F, Cl, OCH3, t-Bu) decompose to form BX3 and B5H9 as the volatile products. Reactions of BCl2B5H8 with excess B2Cl4 yield (BCl2)3B5H6, a compound of limited thermal stability, but no evidence for further BCl2 substitution on the pentaborane cage was obtained. Reductions of BCl2B5H8 with LiBH4 in C6H5Cl or C6H4Cl2 form apparent equilibrium mixtures of 1:1′,2′-[B5H8][B2H5] and 1:1′-[B5H8][B2H5]. One or both of these compounds decompose with the evolution of B2H6, B5H9, and coupled pentaborane cages (B5H7)n, where n can be at least as large as 8. The 11B NMR and mass spectrometric evidence from the last reaction is consistent with the initial dimerization of the hexaborane 1-BH2B5H8, which is rapidly followed by the formation of 1:1′-[B5H8][B2H5], the cross product arising from the interaction of B2H6 with (BH2B5H8)2, and then isomerization of this heptaborane to 1:1′,2′-[B5H8][B2H5].
- Saulys,Morrison
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p. 4174 - 4179
(2008/10/08)
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- Interaction of metal carbonyl hydrides with Lewis acids
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Recent studies on Lewis acid promoted CO migratory insertion to produce metal acyls prompted a comprehensive study of the interaction of metal carbonyl hydrides with molecular Lewis acids. Stable rnetal formyl formation was not achieved in this study, but insight was obtained into reactions that may compete with migratory insertion in metal carbonyl hydrides. The reactivity of metal carbonyl hydrides with strong Lewis acids is dominated by the basic character of the hydride ligand. Variable-temperature multinuclear NMR characterization of the low-temperature complex Mn(CO)5-H-BCl3 is presented. The susceptibility to electrophilic metal hydrogen bond cleavage increases with decreasing acidity of the hydride, Steric factors are also important as evidenced by the observation that H3Re3(CO)12 is much more resistant to eiectrophilic attack than is HRe(CO)5. Also discussed are reactions of Lewis acids with HCo(CO)4, [PPN][HFe(CO)4], [Ir(CO)2(PPh3)2H2][BPh4], HMn(CO)4PPh3, CpMo(CO)3H; and CpMo(CO)2(PPh3)H.
- Richmond, Thomas G.,Basoio, Fred,Shriver, Ouward F.
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p. 1624 - 1628
(2008/10/08)
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- Reaction of Boron Trichloride with Hydrogen Initiated by Pulsed 10.6-μm Radiation
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Bands due to the molecule BCl have been detected in the electronic absorption spectra of the luminous plasma formed in a mixture of boron trichloride and hydrogen in the field of pulsed 10.6-μm monochromatic radiation.Local thermodynamic equilibrium is established in the plasma, whose temperature has been measured.It is concluded that the reaction between boron trichloride and hydrogen initiated by monochromatic radiation is a homogeneous thermal reaction.
- Moskvitina, E. N.,Nikonorov, A. P.,Kuzyakov, Yu. Ya.
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p. 388 - 391
(2007/10/02)
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- THERMODYNAMIC PROPERTIES OF BHCL2 FROM THE EQUILIBRATION OF BCL3-H2 MIXTURES
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In the temperature range 700 to 850 C, BCl//3-H//2 mixtures give BHCl//2 and HCl as the only gaseous products. Analysis of equilibrium gas mixtures gave equilibrium constants from which the standard formation enthalpy and standard entropy of BHCl//2 were
- ATTWOOD B,SHELTON RAJ
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p. 131 - 134
(2008/10/08)
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- Preparation and some reactions of difluoroborane
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Difluoroborane is produced by the direct interaction of boron trifluoride with diborane in the gas phase at 100° or above. Pyrolysis of BF3-B2H6 mixtures at 250° for periods of 30 min to 1 hr, followed by rapid quenching,
- Coyle,Cooper,Ritter
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p. 1014 - 1020
(2008/10/08)
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- Reactions of pentaborane(9) and pentaborane derivatives
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The preparations of a number of pentaborane derivatives are described and 11B and 1H nmr spectra recorded and correlated. Assessments of alternative preparative schemes are given. An extension of the apex to base rearrangement reaction to polyalkyl pentaboranes reveals the following trends: the rate of rearrangement decreases with increasing number of alkyl substituents on the pentaborane framework; the rate increases with the use of stronger and less sterically hindered bases. Mechanistic inferences are discussed.
- Onak, Thomas,Dunks, Gary B.,Searcy, I. William,Spielman
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p. 1465 - 1471
(2007/12/19)
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