甲基乙硼烷
甲基乙硼烷 | |
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IUPAC名 Methyldiborane | |
別名 | 一甲基乙硼烷 |
識別 | |
CAS號 | 23777-55-1 [1] |
SMILES |
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性質 | |
化學式 | CH 3BH 3BH 2 |
莫耳質量 | 41.70 g·mol⁻¹ |
外觀 | 無色氣體 |
密度 | 0.546 g/ml(-126 ℃)[2] |
沸點 | -43 °C(230 K)([4]) |
蒸氣壓 | 55 torr(−78.5 ℃)[2] |
偶極矩 | 0.56 D[3] |
熱力學 | |
ΔfHm⦵298K | −14 kcal/mol(液態) −9 kcal/mol(氣態)[5] |
相關物質 | |
相關烷基硼烷 | 1,1-二甲基硼烷 1,2-二甲基硼烷 三甲基硼烷 四甲基硼烷 三甲基硼 乙基乙硼烷 |
相關化學品 | 乙硼烷 |
若非註明,所有數據均出自標準狀態(25 ℃,100 kPa)下。 |
甲基乙硼烷是乙硼烷的一個氫原子被甲基取代而成的化合物,化學式 CH3B2H5。它可以看作是甲基甲硼烷(CH3BH2)和甲硼烷(BH3)通過兩個三中心二電子鍵連接而成的化合物。[6]乙硼烷的其它甲基化衍生物包括1,1-二甲基乙硼烷、1,2-二甲基乙硼烷、三甲基乙硼烷、四甲基乙硼烷和三甲基硼(不以二聚體形式存在)。在室溫下,甲基乙硼烷是這些分子組成的平衡混合物。[7]
乙硼烷的各種甲基化衍生物都是赫爾曼·歐文·施勒辛格和A. O. Walker於1930年代首次合成的。[8][9]
合成
乙硼烷的各種甲基化衍生物都可以由乙硼烷和三甲基硼反應而成。[7]在0 °C且乙硼烷過量時,反應最初會緩慢產生甲基乙硼烷,但1,1-二甲基乙硼烷的含量也會逐漸增加,直到消耗完所有的三甲基硼。反應產生的甲基乙硼烷最後會和乙硼烷和二甲基乙硼烷形成平衡。在0 °C下, 2B2H5Me ←→ B2H6 + (BH2Me)2 的平衡常數為0.07,所以這個混合物的主要成分是甲基乙硼烷,但其中也有相當量的乙硼烷和二甲基乙硼烷。[10]在乙硼烷和三甲基硼的比例為4:1下,反應會產生最多的甲基乙硼烷。[11]
甲基鋰和乙硼烷反應也可以產生甲基乙硼烷,產率 20%。[12]
四甲基鉛和乙硼烷在二甲氧基乙烷下反應也會產生各種乙硼烷的甲基化衍生物。[13]
其它生成甲基乙硼烷的方法包括三甲基硼和氫氣在80-200 °C和高壓下反應,或是硼氫化物和三甲基硼在氯化氫、氯化鋁或氯化硼存在下的反應。如果使用的硼氫化物是硼氫化鈉,那麼反應會產生甲烷。反應使用硼氫化鋰就不會產生甲烷,[8]但會產生二甲基氯化硼和甲基二氯化硼。[8]
Cp2Zr(CH3)2和四氫呋喃的反應也可以生成甲基乙硼烷。[14]
三甲基鎵和乙硼烷在-45°C下反應,生成甲基乙硼烷和硼氫化二甲基鎵:
- 2(CH3)3Ga + B2H6 → (CH3)2GaBH4 + CH3B2H5.[15]
在室溫下,這個反應會產生一種揮發性物質,它會分解成金屬鎵。
- (CH3)3Ga + 3B2H6 → Ga + 3CH3B2H5 +1.5H2.[15]
反應
在-78.5 °C下,甲基乙硼烷會緩慢分解成乙硼烷和1,1-二甲基乙硼烷,[2]而在溶液中的甲基乙硼烷對這個反應更穩定。[16]
- 2MeB2H5 ⇌ 1,1-Me2B2H4 + B2H6 K=2.8 Me=CH3.[17]
甲基乙硼烷和甲醚反應會生成甲醚硼烷 (CH3)2O.BH3和甲基硼烷,後者會快速二聚成1,2-二甲基乙硼烷。[7][18]其它路易斯鹼也可以發生此反應,這可用來生產1,2-二甲基乙硼烷。[19]
甲基乙硼烷在水中水解成甲基硼酸 CH3B(OH)2.[7]它和三甲胺反應,生成固體加合物三甲胺合甲基硼烷 (CH3)3N—BHCH3和三甲胺合硼烷 (CH3)3N—BH3。[7]
甲基乙硼烷接觸到空氣時會自燃。[2]它在150 °C下的氧化會產生2-甲基-1,3,4-三氧-2,5-二硼環戊烷。這是含有三個氧原子和兩個硼原子組成的五元環的化合物,其中甲基連接到一個硼原子上。反應也會產生二甲基-1,3,4-三氧-2,5-二硼環戊烷和三甲基環硼氧烷,以及碳氫化合物、乙硼烷、氫氣和二甲氧基硼烷。[20]
甲基乙硼烷和氨反應,生成氨基二甲基硼(NH2BMe2)。這種物質加熱到180 °C時會生成B-甲基化的環硼氮烷,其中接在硼原子的甲基數量可以是零個、一個、兩個或三個。[21][22]
甲基乙硼烷可以甲基化丁硼烷:
- CH3B2H5 + B4H10 → 2-CH3B4H9 + B2H6[23]
參考資料
- ^ Jane E. Macintyre (編). Dictionary of Organometallic Compounds. 1994-11-10: 463 [2022-08-03]. ISBN 9780412430602. (原始內容存檔於2022-08-03).
- ^ 2.0 2.1 2.2 2.3 Bunting, Roger K. 55 1-Methyldiborane. Duward F. Shriver (編). Inorganic Syntheses, Volume 19. John Wiley and Sons. 22 Sep 2009: 237–238. ISBN 978-0471045427.
- ^ Chiu, C. W.; Burg, A. B.; Beaudet, R. A. Molecular structure determination of methyldiborane. Inorganic Chemistry. March 1982, 21 (3): 1204–1208. doi:10.1021/ic00133a064.
- ^ Lamneck, John H Jr; Kaye, Samuel. Thermal reaction of diborane with trimethylborane. National Advisory Committee for Aeronautics. 4 September 1958 [2022-08-03]. (原始內容存檔於2022-08-03).
- ^ Altschuller, Aubrey P. Calculated Heats of Formation and Combustion of Boron Compounds (Boron, Hydrogen, Carbon, Silicon) (PDF). NACA Research Memorandum. Cleveland, Ohio: National Advisory Committee for Aeronautics: 22. 4 October 1955 [14 August 2015]. (原始內容存檔 (PDF)於2020-12-05).
- ^ 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. doi:10.1016/s0040-4039(00)96380-9.
- ^ 7.0 7.1 7.2 7.3 7.4 Bell, R. P.; Emeléus, H. J. The boron hydrides and related compounds. Quarterly Reviews, Chemical Society. 1948, 2 (2): 132. doi:10.1039/QR9480200132.
- ^ 8.0 8.1 8.2 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. 1965: 3513–3520. doi:10.1039/JR9650003513.
- ^ 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. doi:10.1021/ja01307a009.
- ^ van Aalten, Lloyd; Seely, G. R.; Oliver, Juhn; Ritter, D. M. Kinetics and Equilibria in the Alkylation of Diborane Preliminary Report (PDF). Advances in Chemistry 32. American Chemical Society. 1 June 1961: 107–114 [2022-08-03]. ISBN 978-0-8412-0033-3. doi:10.1021/ba-1961-0032.ch012. (原始內容存檔 (PDF)於2022-08-03).
- ^ Carpenter, J.H.; Jones, W.J.; Jotham, R.W.; Long, L.H. The Raman spectra of the methyldiboranes—II Monomethyldiborane and trimethyldiborane, and characteristic frequencies of the methyldiboranes. Spectrochimica Acta Part A: Molecular Spectroscopy. September 1971, 27 (9): 1721–1734. Bibcode:1971AcSpA..27.1721C. doi:10.1016/0584-8539(71)80227-1.
- ^ Massey, A. G. Chapter 2. The typical elements. Part II: Group III. Annual Reports on the Progress of Chemistry, Section A. 1979, 76: 13–15. doi:10.1039/IC9797600013.
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- ^ 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. doi:10.1021/ja00373a005.
- ^ 15.0 15.1 Schlesinger, H. I.; Brown, Herbert C. The Borohydrides of Gallium. Journal of the American Chemical Society. September 1943, 65 (9): 1787 [17 August 2015]. doi:10.1021/ja01249a512. (原始內容存檔於2022-08-03).
- ^ 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. doi:10.1021/jo00375a031.
- ^ Onak, Thomas. Carboranes and Organo-Substituted Boron Hydrides. Stone, F. G. A.; West, Robert (編). Advances in Organometallic Chemistry. New York, London: Academic Press. 1 January 1966: 284 [19 August 2015]. ISBN 9780080580043.
- ^ Adams, Roy M. Organoboron Compounds (PDF). Metal-Organic Compounds. Advances in Chemistry 23. September 1959: 92 [17 August 2015]. ISBN 978-0-8412-0024-1. doi:10.1021/ba-1959-0023.ch010. (原始內容存檔 (PDF)於2019-07-20).
- ^ Wade, Kenneth. The General Chemistry of the Boron Hydrides. Electron Deficient Compounds. Thomas Nelson. 1971: 91–92 [17 August 2015]. ISBN 978-1-4684-6056-8. (原始內容存檔於2022-08-03).
- ^ Barton, Lawrence; Crump, John M.; Wheatley, Jeffrey B. Trioxadiborolanes from the oxidation of methyldiborane. Journal of Organometallic Chemistry. June 1974, 72 (1): C1–C3. doi:10.1016/s0022-328x(00)82027-6.
- ^ Sheldon, J. C.; Smith, B. C. The borazoles. Quarterly Reviews, Chemical Society. 1960, 14 (2): 202. doi:10.1039/QR9601400200.
- ^ Schlesinger, H. I.; Horvitz, Leo; Burg, A. B. Hydrides of Boron. VI. The Action of Ammonia on the Methyl Diboranes. Journal of the American Chemical Society. March 1936, 58 (3): 409–414. doi:10.1021/ja01294a008.
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擴展閱讀
- Carpenter, J. H.; Jones, W. J.; Jotham, R. W.; Long, L. H. Laser-source Raman spectroscopy and the Raman spectra of the methyldiboranes. Chemical Communications (London). 1968, (15): 881. doi:10.1039/C19680000881.
- Lehmann, Walter J.; Wilson, Charles O.; Shapiro, I. Infrared Spectra of Alkyldiboranes. I. Monomethyldiboranes. The Journal of Chemical Physics. 1960, 32 (4): 1088. Bibcode:1960JChPh..32.1088L. doi:10.1063/1.1730853.
- Crompton, T. R. Gas Chromatography of Organometallic Compounds. Springer. 6 December 2012: 80–83 [17 August 2015]. ISBN 9781468442267. (原始內容存檔於2022-08-03). methyldiborane in a gas chromatograph
- Penn, R. E.; Buxton, L. W. Microwave spectrum of methyldiborane. The Journal of Chemical Physics. 1977, 67 (2): 831. Bibcode:1977JChPh..67..831P. doi:10.1063/1.434845.
- Davidson, G. Elements of Group III. C. C. Addison (編). Inorganic Chemistry of the Main-Group Elements. 1973: 57 [2022-08-03]. ISBN 9780851867526. (原始內容存檔於2022-08-03). Infrared lines
- Isadore Shapiro, C. O. Wilson, J. F. Ditter, W. J. Lehmann. Mass Spectrometry in Boron Chemistry (PDF). Borax to Boranes. Advances in Chemistry Series 32. American Chemical Society. 1961: 135–136 [2022-08-03]. ISBN 978-0-8412-0033-3. doi:10.1021/ba-1961-0032.ch014. (原始內容存檔 (PDF)於2022-08-03). mass spectroscopy
- Kapshtal, V. N.; Sverdlov, L. M. Sum rules for the frequencies and squares of the frequencies of the vibrations in methyl-substituted diborane derivatives. Soviet Physics Journal. November 1968, 11 (11): 120–122. Bibcode:1968SvPhJ..11k.120K. S2CID 121517718. doi:10.1007/BF00816081.