1,1-Dimethyldiborane

1,1-Dimethyldiborane changed changed 1,1-dimethyldiborane.svg skin-invert-image 150px 1,1-Dimethyldiborane(6) Unsymmetrical dimethyldiborane 16924-32-6 Dictionary of Organometallic Compounds Jane E. Macintyre https://books.google.com/books?id=6F4MeeopZWQC&pg=PA468 468 9780412430602 1994-11-10 CRC Press C[B]1(C)[H][BH2][H]1 1S/C2H10B2/c1-4(2)5-3-6-4/h3H2,1-2H3 KEWIJCBOFAPULG-UHFFFAOYSA-N 2 10 2 Colorless gas Soluble in ether, pentane, tetrahydrofuran organic solvents -150.2 -4 -25 kcal/mol Baker Charles J. The Fire Fighter's Handbook of Hazardous Materials 2001 Jones & Bartlett Learning 152 https://books.google.com/books?id=ekiWRT80VbsC&pg=PA152 9780962705212 2 2 alkyl boranes MethyldiboraneTrimethyldiboraneTetramethyldiboraneTrimethylboraneDiethyldiborane 1,1-Dimethyldiborane is the organoboron compound with the formula (CH3)2B(μ-H)2BH2. A pair of related 1,2-dimethyldiboranes are also known.Srebnik Morris Cole Thomas E. Brown Herbert C. Methylborane - a remarkable unhindered monoalkylborane which achieves the controlled sequential hydroboration of representative alkenes Tetrahedron Letters January 1987 28 33 3771–3774 10.1016/s0040-4039(00)96380-9 It is a colorless gas that ignites in air. Formation The methylboranes were first prepared by H. I. Schlesinger and A. O. Walker in the 1930s.Long L. H. Wallbridge M. G. H. 646. The chemistry of boron. Part VI. New preparative methods and decomposition studies relating to methyldiboranes Journal of the Chemical Society (Resumed) 1965 3513–3520 10.1039/JR9650003513 https://pubs.rsc.org/en/content/articlepdf/1965/jr/jr9650003513 subscription Schlesinger H. I. Walker A. O. Hydrides of Boron. IV. The Methyl Derivatives of Diborane Journal of the American Chemical Society April 1935 57 4 621–625 10.1021/ja01307a009 1935JAChS..57..621S Methylboranes are formed by the reaction of diborane and trimethylborane. This reaction produces four different substitution of methyl with hydrogen on diborane. Produced are 1-methyldiborane, 1,1-dimethyldborane, 1,1,2-trimethyldiborane, and 1,1,2,2-tetramethyldiborane.Bell R. P. Emeléus H. J. The boron hydrides and related compounds Quarterly Reviews, Chemical Society 1948 2 2 132 10.1039/QR9480200132 Tetramethyl lead reacts with diborane in a 1,2-dimethoxyethane solvent at room temperature to make a range of methyl substituted diboranes, ending up at trimethylborane, but including 1,1-dimethyldiborane, and trimethyldiborane. The other outputs of the reaction are hydrogen gas and lead metal.Holliday A.K. N. Jessop G. The reaction of tetramethyllead with diborane Journal of Organometallic Chemistry November 1967 10 2 291–293 10.1016/s0022-328x(00)93089-4 Other methods to form methyldiboranes include heating trimethylborane with hydrogen. Alternatively trimethylborane reacts with borohydride salts with in the presence of hydrogen chloride, aluminium chloride, or boron trichloride. If the borohydride is sodium borohydride, then methane is a side product. If the metal is lithium then no methane is produced. dimethylchloroborane and methyldichloroborane are also produced as gaseous products. When Cp2Zr(CH3)2 reacts with borane dissolved in tetrahydrofuran, a borohydro group inserts into the zirconium carbon bond, and methyl diboranes are produced.Marsella John A. Caulton Kenneth G. Dealkylation of zirconium(IV) by borane: the intimate mechanism of an alkyl transfer reaction Journal of the American Chemical Society May 1982 104 9 2361–2365 10.1021/ja00373a005 1982JAChS.104.2361M In ether dimethylcalcium reacts with diborane to produce dimethyldiborane and calcium borohydride:James B. D. Wallbridge M. G. H. Lippard Stephen J. Progress in Inorganic Chemistry, Volume 11 1970 Wiley 0471-54081-1 185 https://books.google.com/books?id=8N6nFvNzfv0C&pg=PA185 Metal Tetrahydroborates Ca(CH3)2 + 2 B2H6 → Ca(BH4)2 + B2H4(CH3)2 1,2-dimethyldiborane slowly converts on standing to 1,1-dimethyldiborane.Lehmann Walter J. Wilson Charles O. Shapiro I. Infrared Spectra of Alkyldiboranes. III. 1,2-Dimethyl- and 1,2-Diethyldiboranes The Journal of Chemical Physics 1960 33 2 590 10.1063/1.1731190 1960JChPh..33..590L Gas chromatography can be used to determine the amounts of the methyl boranes in a mixture. The order they elute are diborane, monomethyldiborane, trimethylborane, 1,1-dimethyldiborane, 1,2-dimethyldiborane, trimethyldiborane, and finally tetramethyldiborane.Seely G. R. Oliver J. P. Ritter D. M. Gas-Liquid Chromatographic Analysis of Mixtures Containing Methyldiboranes Analytical Chemistry December 1959 31 12 1993–1995 10.1021/ac60156a032 1959AnaCh..31.1993S Selected properties 1,1-Dimethyldiborane has a dipole moment of 0.87 d.Chiu C. W. Burg A. B. Beaudet R. A. Microwave spectrum, dipole moment, barrier to internal rotation of 1,1-dimethyldiborane The Journal of Chemical Physics 15 March 1983 78 6 3562–3566 10.1063/1.445182 1983JChPh..78.3562C The predicted heat of formation for the liquid is ΔH0f=-31 kcal/mol, and for the gas -25 kcal/mol. Heat of vapourisation was measured at 5.5 kcal/mol.Altschuller Aubrey P. Calculated Heats of Formation and Combustion of Boron Compounds (Boron, Hydrogen, Carbon, Silicon) NACA Research Memorandum http://naca.central.cranfield.ac.uk/reports/1955/naca-rm-e55g26.pdf National Advisory Committee for Aeronautics 14 August 2015 Cleveland, Ohio 22 4 October 1955 Reactions At −78.5 °C, methyldiborane disproportionates slowly, first to diborane and 1,1-dimethyldiborane.Duward F. Shriver Bunting Roger K. Inorganic Syntheses, Volume 19 22 Sep 2009 John Wiley and Sons 237–238 https://books.google.com/books?id=Tk3HUFj9XnkC&pg=PA237 55 1-Methyldiborane 978-0471045427 In solution methylborane is more stable against disproportionation than dimethylborane.Brown Herbert C. Cole Thomas E. Srebnik Morris Kim Kee Won Hydroboration. 79. Preparation and properties of methylborane and dimethylborane and their characteristics as hydroborating agents. Synthesis of tertiary alcohols containing methyl groups via hydroboration The Journal of Organic Chemistry December 1986 51 25 4925–4930 10.1021/jo00375a031Onak Thomas Stone F. G. A. West Robert Advances in Organometallic Chemistry 1 January 1966 Academic Press New York, London 284 https://books.google.com/books?id=AHEPoIx22iwC&pg=PA266 19 August 2015 Carboranes and Organo-Substituted Boron Hydrides 9780080580043 2 MeB2H5 → 1,1-Me2B2H4 + B2H6, K = 2.8, Me = CH3 3 [1,1-Me2B2H4] → 2 Me3B2H3 + B2H6, K = 0.00027 Trimethyldiborane partially disproportionates over a period of hours at room temperature to yield tetramethyldiborane and 1,2-dimethyldiborane. Over a period of weeks 1,1-dimethyldiborane appears as well.Lehmann Walter J. Wilson Charles O. Shapiro I. Infrared Spectra of Alkyldiboranes. V. Tri- and Tetramethyl- and Ethyldiboranes The Journal of Chemical Physics 1961 34 3 783 10.1063/1.1731675 1961JChPh..34..783L Gentler oxidation of 1,1-dimethyldiborane at 80 °C yields 2,5-dimethyl-1,3,4-trioxadiboralane, a volatile liquid that contains a ring of two boron and three oxygen atoms.Barton Lawrence Crump John M. Wheatley Jeffrey B. Trioxadiborolanes from the oxidation of methyldiborane Journal of Organometallic Chemistry June 1974 72 1 C1–C3 10.1016/s0022-328x(00)82027-6 An intermediate in this reaction is two molecules of dimethylborylhydroperoxide (CH3)2BOOH. (CAS 41557-62-5)Barton Lawrence Crump John M. Oxidation of 1,1-dimethyldiborane. Gas-phase peroxide intermediates Inorganic Chemistry November 1973 12 11 2506–2510 10.1021/ic50129a003 When methyldiborane is oxidised around 150 °C a similar substance methyltrioxadiboralane is produced. At the same time dimethyltrioxadiboralane and trimethylboroxine are also formed, and also hydrocarbons, diborane, hydrogen, and dimethoxyborane (dimethyl methylboronic ester). References 30em Category:Alkylboranes Category:Explosive gases Category:Organic compounds with 2 carbon atoms