甲基乙硼烷

甲基乙硼烷
	IUPAC名; Methyldiborane
别名	一甲基乙硼烷
识别
CAS号	23777-55-1
SMILES	C[BH]1[H][BH2][H]1;
性质
化学式	CH; 3BH; 3BH; 2
摩尔质量	41.70 g·mol⁻¹
外观	无色气体
密度	0.546 g/ml（-126 ℃）
沸点	-43 °C（230 K）（）
蒸气压	55 torr（−78.5 ℃）
偶极矩	0.56 D
热力学
ΔfHm⦵298K	−14 kcal/mol（液态）; −9 kcal/mol（气态）
相关物质
相关烷基硼烷	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
相关化学品	乙硼烷
	若非注明，所有数据均出自标准状态（25 ℃，100 kPa）下。

甲基乙硼烷是乙硼烷的一个氢原子被甲基取代而成的化合物，化学式 CH₃B₂H₅。它可以看作是甲基甲硼烷（希腊语：Μεθυλοβοράνιο）（CH₃BH₂）和甲硼烷（BH₃）通过两个三中心二电子键连接而成的化合物。^[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（不以二聚体形式存在）。在室温下，甲基乙硼烷是这些分子组成的平衡混合物。^[7]

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乙硼烷的各种甲基化衍生物都是赫尔曼·欧文·施勒辛格（英语：Hermann Irving Schlesinger）和A. O. Walker于1930年代首次合成的。^[8]^[9]

合成

乙硼烷的各种甲基化衍生物都可以由乙硼烷和三甲基硼反应而成。^[7]在0 °C且乙硼烷过量时，反应最初会缓慢产生甲基乙硼烷，但1,1-二甲基乙硼烷的含量也会逐渐增加，直到消耗完所有的三甲基硼。反应产生的甲基乙硼烷最后会和乙硼烷和二甲基乙硼烷形成平衡。在0 °C下， 2B₂H₅Me ←→ B₂H₆ + (BH₂Me)₂ 的平衡常数为0.07，所以这个混合物的主要成分是甲基乙硼烷，但其中也有相当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为4:1下，反应会产生最多的甲基乙硼烷。^[11]

甲基锂和乙硼烷反应也可以产生甲基乙硼烷，产率 20%。^[12]

四甲基铅和乙硼烷在二甲氧基乙烷下反应也会产生各种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氢气在80-200 °C和高压下反应，或是硼氢化物和三甲基硼在氯化氢、氯化铝或氯化硼存在下的反应。如果使用的硼氢化物是硼氢化钠，那么反应会产生甲烷。反应使用硼氢化锂就不会产生甲烷，^[8]但会产生二甲基氯化硼和甲基二氯化硼。^[8]

Cp₂Zr(CH₃)₂和四氢呋喃的反应也可以生成甲基乙硼烷。^[14]

三甲基镓和乙硼烷在-45°C下反应，生成甲基乙硼烷和硼氢化二甲基镓：

2(CH₃)₃Ga + B₂H₆ → (CH₃)₂GaBH₄ + CH₃B₂H₅.^[15]

在室温下，这个反应会产生一种挥发性物质，它会分解成金属镓。

(CH₃)₃Ga + 3B₂H₆ → Ga + 3CH₃B₂H₅ +1.5H₂.^[15]

反应

在-78.5 °C下，甲基乙硼烷会缓慢分解成乙硼烷和1,1-二甲基乙硼烷，^[2]而在溶液中的甲基乙硼烷对这个反应更稳定。^[16]

2MeB₂H₅ ⇌ 1,1-Me₂B₂H₄ + B₂H₆ K=2.8 Me=CH₃.^[17]

甲基乙硼烷和甲醚反应会生成甲醚硼烷 (CH₃)₂O.BH₃和甲基硼烷，后者会快速二聚成1,2-二甲基乙硼烷。^[7]^[18]其它路易斯碱也可以发生此反应，这可用来生产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]它和三甲胺反应，生成固体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]

甲基乙硼烷接触到空气时会自燃。^[2]它在150 °C下的氧化会产生2-甲基-1,3,4-三氧-2,5-二硼环戊烷。这是含有三个氧原子和两个硼原子组成的五元环的化合物，其中甲基连接到一个硼原子上。反应也会产生二甲基-1,3,4-三氧-2,5-二硼环戊烷和三甲基环硼氧烷，以及碳氢化合物、乙硼烷、氢气和二甲氧基硼烷。^[20]

甲基乙硼烷和氨反应，生成氨基二甲基硼（NH₂BMe₂）。这种物质加热到180 °C时会生成B-甲基化的环硼氮烷，其中接在硼原子的甲基数量可以是零个、一个、两个或三个。^[21]^[22]

甲基乙硼烷可以甲基化丁硼烷：

CH₃B₂H₅ + B₄H₁₀ → 2-CH₃B₄H₉ + B₂H₆^[23]

参考资料

[1]
Jane E. Macintyre (编). Dictionary of Organometallic Compounds. 1994-11-10: 463 [2022-08-03]. ISBN 9780412430602. （原始内容存档于2022-08-03）.
[2]
Bunting, Roger K. 55 1-Methyldiborane. Duward F. Shriver (编). Inorganic Syntheses, Volume 19. John Wiley and Sons. 22 Sep 2009: 237–238. ISBN 978-0471045427.
[3]
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.
[4]
Lamneck, John H Jr; Kaye, Samuel. Thermal reaction of diborane with trimethylborane. National Advisory Committee for Aeronautics. 4 September 1958 [2022-08-03]. （原始内容存档于2022-08-03）.
[5]
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]. （原始内容存档 (PDF)于2020-12-05）.
[6]
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]
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]
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.
[9]
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.
[10]
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. （原始内容存档 (PDF)于2022-08-03）.
[11]
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.
[12]
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.
[13]
Holliday, A.K.; N. Jessop, G. The reaction of tetramethyllead with diborane. Journal of Organometallic Chemistry. November 1967, 10 (2): 291–293. doi:10.1016/s0022-328x(00)93089-4.
[14]
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]
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. （原始内容存档于2022-08-03）.
[16]
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.
[17]
Onak, Thomas. Carboranes and Organo-Substituted Boron Hydrides. Stone, F. G. A.; West, Robert (编). Advances in Organometallic Chemistry. New York, London: Academic Press. 1 January 1966: 284 [19 August 2015]. ISBN 9780080580043.
[18]
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. （原始内容存档 (PDF)于2019-07-20）.
[19]
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. （原始内容存档于2022-08-03）.
[20]
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.
[21]
Sheldon, J. C.; Smith, B. C. The borazoles. Quarterly Reviews, Chemical Society. 1960, 14 (2): 202. doi:10.1039/QR9601400200.
[22]
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.
[23]
Onak, Thomas. Organoborane chemistry. New York: Academic Press. 1975: 193–194 [17 August 2015]. ISBN 978-0-12-526550-8. （原始内容存档于2022-08-03）.

扩展阅读

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. （原始内容存档于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 (编). Inorganic Chemistry of the Main-Group Elements. 1973: 57 [2022-08-03]. ISBN 9780851867526. （原始内容存档于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. （原始内容存档 (PDF)于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.

[1] [1]
Jane E. Macintyre (编). Dictionary of Organometallic Compounds. 1994-11-10: 463 [2022-08-03]. ISBN 9780412430602. （原始内容存档于2022-08-03）.

[Bunting-2] [2]
Bunting, Roger K. 55 1-Methyldiborane. Duward F. Shriver (编). Inorganic Syntheses, Volume 19. John Wiley and Sons. 22 Sep 2009: 237–238. ISBN 978-0471045427.

[3] [3]
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-4] [4]
Lamneck, John H Jr; Kaye, Samuel. Thermal reaction of diborane with trimethylborane. National Advisory Committee for Aeronautics. 4 September 1958 [2022-08-03]. （原始内容存档于2022-08-03）.

[Altschuller55-5] [5]
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]. （原始内容存档 (PDF)于2020-12-05）.

[Srebnik87-6] [6]
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.

[bell48-7] [7]
Bell, R. P.; Emeléus, H. J. The boron hydrides and related compounds. Quarterly Reviews, Chemical Society. 1948, 2 (2): 132. doi:10.1039/QR9480200132.

[long-8] [8]
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.

[9] [9]
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.

[va61-10] [10]
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. （原始内容存档 (PDF)于2022-08-03）.

[carp2-11] [11]
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.

[type-12] [12]
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.

[holl67-13] [13]
Holliday, A.K.; N. Jessop, G. The reaction of tetramethyllead with diborane. Journal of Organometallic Chemistry. November 1967, 10 (2): 291–293. doi:10.1016/s0022-328x(00)93089-4.

[14] [14]
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.

[gah-15] [15]
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. （原始内容存档于2022-08-03）.

[brown86-16] [16]
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.

[TOnak-17] [17]
Onak, Thomas. Carboranes and Organo-Substituted Boron Hydrides. Stone, F. G. A.; West, Robert (编). Advances in Organometallic Chemistry. New York, London: Academic Press. 1 January 1966: 284 [19 August 2015]. ISBN 9780080580043.

[18] [18]
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. （原始内容存档 (PDF)于2019-07-20）.

[19] [19]
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. （原始内容存档于2022-08-03）.

[barton74-20] [20]
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.

[21] [21]
Sheldon, J. C.; Smith, B. C. The borazoles. Quarterly Reviews, Chemical Society. 1960, 14 (2): 202. doi:10.1039/QR9601400200.

[schles36-22] [22]
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.

[thoon-23] [23]
Onak, Thomas. Organoborane chemistry. New York: Academic Press. 1975: 193–194 [17 August 2015]. ISBN 978-0-12-526550-8. （原始内容存档于2022-08-03）.

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