甲烯鎓離子

甲烯鎓離子
	IUPAC名; Methylium
別名	Methyl cation; Carbanylium
識別
CAS號	14531-53-4
PubChem	644094
SMILES	[CH3+];
InChI	1S/CH3/h1H3/q+1;
InChIKey	UHDUIDUEUEQND-UHFFFAOYSA-N
ChEBI	29437
性質
化學式	CH3
摩爾質量	15.03 g·mol−1
相關物質
相關等離子化合物	甲硼烷
	若非註明，所有數據均出自標準狀態（25 ℃，100 kPa）下。

在有機化學中，甲烯鎓離子（又稱質子化亞甲基）是一種陽離子，化學式為CH+
3。它可以視作一個亞甲基自由基（:CH
2）加上一個質子（H+
），或一個甲基自由基（英語：methyl radical）（•CH
3）去除一個電子。它是碳正離子和烯鎓離子（英語：enium ion），是最簡單的烯鎓離子（英語：enium ion）。^[2]

結構

實驗和計算普遍表示，甲烯鎓離子具有平面結構和三重對稱性。^[2]離子的碳原子是sp²雜化的原型（和精確）示例。

製備和反應

對於低壓的質譜研究，甲烯鎓離子可以通過甲基自由基的紫外線光電離，^[2]或將中性甲烷與單原子陽離子（如C+
和Kr+
）碰撞製備。^[3]在這種條件下，它會與乙腈CH
3CN反應，形成離子(CH
3)
2CN+
。^[4]

捕獲低能電子後（小於6981160217648700000♠1 eV），它會自發地解離。^[5]

它很少在凝聚相下以中間體的形式出現。它被提議為一種反應性中間體，在甲烷與FSO₃H-SbF₅進行質子化或氫化物提取時形成。甲鎓離子非常活潑，對烷烴也是如此。^[6]

參見

參考文獻

^ International Union of Pure and Applied Chemistry. Nomenclature of Organic Chemistry: IUPAC Recommendations and Preferred Names 2013. The Royal Society of Chemistry. 2014: 1089. ISBN 978-0-85404-182-4. doi:10.1039/9781849733069.
^ ^2.0 ^2.1 ^2.2 L. Golob, N. Jonathan, A. Morris, M. Okuda, K.J. Ross (1972), "The first ionization potential of the methyl radical as determined by photoelectron spectroscopy". Journal of Electron Spectroscopy and Related Phenomena, volume 1, issue 5, pp. 506–508 doi:10.1016/0368-2048(72)80022-7
^ R.B. Sharma, N.M. Semo, W.S. Koski (1987), "Dynamics of the reactions of methylium, methylene radical cation, and methyliumylidene with acetylene". Journal of Physical Chemistry, volume 91, issue 15, pp. 4127–4131 doi:10.1021/j100299a037
^ Murray J. McEwan, Arthur B. Denison, Wesley T. Huntress Jr., Vincent G. Anicich, J. Snodgrass, M.T. Bowers (1989), "Association reactions at low pressure. 2. The methylium/methyl cyanide system". Journal of Physical Chemistry, volume 93, issue 10, pp. 4064–4068. doi:10.1021/j100347a039
^ E.M. Bahati, M. Fogle, C.R. Vane, M.E. Bannister, R.D. Thomas and V. Zhaunerchyk (2009), "Electron-impact dissociation of CD+
3 and CH+
3 ions producing CD+
2, CH+
and C+
fragment ions". Physical Review, volume 79, article 052703 doi:10.1103/PhysRevA.79.052703
^ Hogeveen, H.; Lukas, J.; Roobeek, C. F. Trapping of the methyl cation by carbon monoxide; formation of acetic acid from methane. Journal of the Chemical Society D: Chemical Communications. 1969, (16): 920. ISSN 0577-6171. doi:10.1039/c29690000920 （英語）.

[1] International Union of Pure and Applied Chemistry. Nomenclature of Organic Chemistry: IUPAC Recommendations and Preferred Names 2013. The Royal Society of Chemistry. 2014: 1089. ISBN 978-0-85404-182-4. doi:10.1039/9781849733069.

[Golob-2] 2.0 ^2.1 ^2.2 L. Golob, N. Jonathan, A. Morris, M. Okuda, K.J. Ross (1972), "The first ionization potential of the methyl radical as determined by photoelectron spectroscopy". Journal of Electron Spectroscopy and Related Phenomena, volume 1, issue 5, pp. 506–508 doi:10.1016/0368-2048(72)80022-7

[Sharma-3] R.B. Sharma, N.M. Semo, W.S. Koski (1987), "Dynamics of the reactions of methylium, methylene radical cation, and methyliumylidene with acetylene". Journal of Physical Chemistry, volume 91, issue 15, pp. 4127–4131 doi:10.1021/j100299a037

[McEwan-4] Murray J. McEwan, Arthur B. Denison, Wesley T. Huntress Jr., Vincent G. Anicich, J. Snodgrass, M.T. Bowers (1989), "Association reactions at low pressure. 2. The methylium/methyl cyanide system". Journal of Physical Chemistry, volume 93, issue 10, pp. 4064–4068. doi:10.1021/j100347a039

[Bahati-5] E.M. Bahati, M. Fogle, C.R. Vane, M.E. Bannister, R.D. Thomas and V. Zhaunerchyk (2009), "Electron-impact dissociation of CD+
3 and CH+
3 ions producing CD+
2, CH+
and C+
fragment ions". Physical Review, volume 79, article 052703 doi:10.1103/PhysRevA.79.052703

[6] Hogeveen, H.; Lukas, J.; Roobeek, C. F. Trapping of the methyl cation by carbon monoxide; formation of acetic acid from methane. Journal of the Chemical Society D: Chemical Communications. 1969, (16): 920. ISSN 0577-6171. doi:10.1039/c29690000920 （英語）.

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