Showing papers on "Diborane published in 1977"
Patent•
22 Aug 1977TL;DR: In this article, a reaction mixture containing as catalysts an oxygen source and an organic boron compound which is soluble in the reaction mixture is used to polymerize polymers of diborane/propadiene adducts.
Abstract: Polymerizable monomers are polymerized in a reaction mixture containing as catalysts (A) an oxygen source and (B) an organic boron compound which is soluble in the reaction mixture, the boron compound being (1) a diborane adduct wherein the boron atoms are linked by a hydrocarbyl group having an aliphatic carbon atom bonded to at least one of the boron atoms, or (2) oligomers based on repeating units containing at least two boron atoms linked by hydrocarbyl groups having an aliphatic carbon atom bonded to at least one of the boron atoms. The diborane adducts include the adduct of borane or a dialkylborane and 1,3-butadiene. The oligomers include polymers of diborane/propadiene adducts. The organoboron catalysts provide rapid initiation of polymerization and the polymerization is relatively insensitive to oxygen concentration, thereby permitting polymerization at ambient temperatures.
35 citations
23 citations
19 citations
TL;DR: In this article, the reactions of organic halides with diborane in THF in the presence of lithium, sodium, potassium or calcium have been examined, and it has been shown that one-step reactions have been shown to be superior to analogous two-stage reactions in which preformed organolithium reagents are allowed to react with Diboranes.
15 citations
TL;DR: In this article, Stewart et al. present a table for X-ray diffraction data in Crvstal Evaluation and Physical Structural Information, NA Publ. IV, Vol. 4, 513-519.
Abstract: International Tables for X-ray Crystallography (1974). Vol. IV. Birmingham: Kynoch Press. JONES, D. S., PAUTLER, D. & COPPENS, P. (1972). Acta Cryst. A28, 635-645. KURKVSUONIO, K. (1968). Acta Cryst. A24, 379-390. LARSON, A. C. & CROMER, D. T. (1974). J. Chem. Phys. 60, 185-192. MCWEENY, R. (1951). Acta Cryst. 4, 513-519. SCHERINGER, C. (1977). Acta Cryst. A33, 588-592. SCHERINGER, C. & REITZ, H. (1976). Acta Cryst. A32, 271273. STEWART, R. F. (1968). J. Chem. Phys. 48, 4882-4889. STEWART, R. F. (1969). J. Chem. Phys. 51, 4569-4577. STEWART, R. F. (1970). J. Chem. Phys. 53, 205-213. STEWART, R. F. (1972). J. Chem. Phys. 57, 1664-1668. STEWART, R. F. (1973). Charge densities from X-ray diffraction data in Crvstal Evaluation and Physical Structural Information, NA Publ. STEWART, R. F. (1976). Acta C~.st. A32, 565-574. WANG, Y., BLESSING, R. H., ROSS, F. K. & COPPENS, P. (1976). Acta Cryst. B32, 572-578.
12 citations
TL;DR: In this article, the concept of vacant orbital contributions to valence structures of known boranes and carboranes has been examined in the light of hyperconjugative interactions and boron framework distortions.
Abstract: Addition of H2 to BH3 yields BH5, which is shown to be of Cs symmetry. Rearrangement mechanisms and hydrogen loss have been examined. Intermediates such as B3H7 and B4H8 have been predicted to have vacant orbital structures in which the stability gained by filling that orbital is balanced by strain in converting a terminal hydrogen to a bridge hydrogen. Other factors, such as hyperconjugative interactions and boron framework distortions are of importance. These factors have been examined also in bridge hydrogen asymmetries and distortions from regular geometry, in the light of vacant orbital contributions to valence structures of known boranes and carboranes. Localization procedures have refined the concepts of where an open three-center bond is useful, where single bond donation becomes important, where fractional bonds occur, and where a more complex description can usefully replace a large number of valence structures. Vacant orbital contributions have also been used to guess where ligand (e.g. H) attack may occur, and at which pair of adjacent boron atoms BH3 may be expected to add. A study of diborane formation indicates favoritism for simultaneous H…B and B…H reaction of compounds of the two distinct BH3 reactants. Reactions of BH3 with higher hydrides, and of higher hydrides with each other may be expected to follow this principle.
10 citations
TL;DR: In this article, some factors which influence the reaction of styrene oxide and related epoxides with diborane in tetrahydrofuran at 25° have been studied.
Abstract: Some factors which influence the reaction of styrene oxide and related epoxides with diborane in tetrahydrofuran at 25° have been studied. Styrene oxide (2-phenyloxiran) and o- and p-methyl-styrene oxide afford essentially the 2-arylethanol. (E)-1-Phenylpropene oxide (trans-2-methyl-3-phenyloxiran) yields 76% 1-phenylpropan-2-ol and 24% 1-phenylpropanol. Indene oxide and 1,2-dihydronaphthalene oxide are both cleanly reduced to indan-2-ol and 1,2,3,4-tetrahydronaphthalen-2-ol respectively. Reduction of 2-phenylpropene oxide afforded only 15% 2-phenylpropanol and 85% of an organoborane which gave 2-phenylpropane-1,3-diol on oxidation, and (E)-2-phenylbut-2-ene oxide gave almost exclusively the corresponding 2-phenylbutane-1,3-diol. The stereochemistry of the diol products is discussed, and it is suggested that the relative stability of incipient benzyl and alkyl carbonium ions influences the mode of reaction.
9 citations
TL;DR: In this paper, the reaction of some sterically crowded styrene epoxides (phenyloxirans) with diborane has been investigated, and the mechanism of the reaction is discussed with supporting evidence from the use of deuterated diboreane.
Abstract: The reaction of some sterically crowded styrene epoxides (phenyloxirans) with diborane has been investigated. (Z)-1-Phenylpropene oxide (cis-2-methyl-3-phenyloxiran) reacts with diborane in tetrahydrofuran at 20° to give, after oxidation, 1-phenylpropan-2-ol(53 %), 1-phenylpropanol (23 %) and 1-phenylpropane-1,3-diol(2%4 ). 2-Methyl-1-phenylpropene oxide (2,2-dimethyl-3-phenyloxiran) under similar conditions affords 2-methyl-1-phenylpropanol (7%) and 2-methyl-1-phenylpropane- 1,3-diol(84%), the major isomer of which was the threo. The epoxide of 2-methyl-3-phenylpropene gives a diol mixture (81%) consisting of the above diols plus 2-benzylpropane-1,3-diol, and 2-methyl- 3-phenylpropanol (3%). The reaction of 1-methyl-2-phenylcyclohexene oxide with diborane gave a complex mixture af products, three of which have been identified. The mechanism of the reaction is discussed with supporting evidence from the use of deuterated diborane.
6 citations
6 citations
TL;DR: In this article, an infrared spectroscopic method was used to investigate the hydroboration of ethylene and propylene as lower olefins with diborane on γ-Al 2 O 3.
6 citations
TL;DR: Methylation of SiH 4, MeSiH 3, Si 2 H 6, GeH 4 and B 2 H6, but not of PH 3 or AsH 3, was observed during reaction (230-324°C) with GaMe 3.
TL;DR: Bis(difluorophosphino) selenide has been characterised by vrbrational, mass, n.m.r., and photoelectron spectroscopy as discussed by the authors.
Abstract: Bis(difluorophosphino) selenide has been prepared by the exchange reactions of PBrF2 and PCLF2 with Se(SiH3)2 and Se(SnBu3)2. It has been characterised by vrbrational, mass, n.m.r., and photoelectron spectroscopy. Spectroscopic results have also been obtained for bis(difluorophosphino) sulphide, prepared by analogous methods. Both compounds react with Bronsted acids to give PF2HSe or PF2HS, and a difluorophos-phine derivative of the acid. Basic properties are shown by the reactions with diborane, which give the mono-borane adducts, and by the displacement of norbornadiene from [Mo(C7H8)(CO)4]. The latter reaction illustrates the potential usefulness of these compounds as chelating bidentate hgands. With chlorine the selenide gives PCl3F2 and PClF2Se.
TL;DR: In this article, the pendant vinyl groups of reactive microgels prepared from 1,4-divinylbenzene or divinyl benzene mixture were converted into hydroxyl groups by hydroboration with diborane.
Abstract: The pendant vinyl groups of reactive microgels prepared from 1,4-divinylbenzene or divinylbenzene mixture were converted into hydroxyl groups by hydroboration with diborane. This reagent enters very fast into the network of the microgels and reacts with all vinyl groups.
TL;DR: The Clemmensen reduction as mentioned in this paper is an effective means of converting acyl and vinylic methylidynetricobalt nona-carbonyl complexes to the corresponding saturated alkyl-IDNIC nonacarbonyl when it is carried out in nonaqueous medium.
Abstract: The Clemmensen reduction is an effective means of converting acyl- and vinylic methylidynetricobalt nona-carbonyl complexes to the corresponding saturated alkylidynetricobalt nonacarbonyl when it is carried out in nonaqueous medium. Diborane in tetrahydrofuran reacts with acyl-substituted cobalt clusters to give a mixture of the corresponding alcohol and alkyl complexes in which the latter predominates.
TL;DR: The microwave spectra of eight isotopic modifications of methyl diborane (CH3B2H5) are reported in this article, and a convenient and general computational scheme for the application of Pierce's "method of second differences" is described and used to determine the rs B⋅⋆B distance of 1.773(5) A.
Abstract: The microwave spectra of eight isotopic modifications of methyl diborane (CH3B2H5) are reported. A convenient and general computational scheme for the application of Pierce’s ’’method of second differences’’ is described and used to determine the rs B⋅⋅⋅B distance of 1.773(5) A. Several experimental results suggest a decrease in this distance of about 0.007 A upon B2H5‐group perdeuteration. The dipole moment is 0.566(6) D with 0.562(5) D and 0.06(3) D a and b components, respectively. The threefold methyl group torsional barrier is 4.28(9) kcal/mole.