二茂镁
二茂镁
|
|
IUPAC名 bis(η5-cyclopentadienyl)magnesium
|
识别
|
CAS号
|
1284-72-6 N
|
PubChem
|
11984632
|
ChemSpider
|
10628001
|
SMILES
|
- [cH-]1cccc1.[cH-]1cccc1.[Mg+2]
|
InChI
|
- 1S/2C5H5.Mg/c2*1-2-4-5-3-1;/h2*1-5H;/q2*-1;+2
|
EINECS
|
603-275-0
|
性质
|
化学式
|
C10H10Mg
|
摩尔质量
|
154.49 g·mol−1
|
外观
|
无色晶体[1]
|
熔点
|
176 °C(449 K)([2])
|
沸点
|
290 °C(563 K)([3])
|
溶解性
|
与水激烈反应,可溶于极性和非极性溶剂。[1]
|
危险性
|
GHS危险性符号
![《全球化学品统一分类和标签制度》(简称“GHS”)中爆炸性物质的标签图案](//upload.wikimedia.org/wikipedia/commons/thumb/4/4a/GHS-pictogram-explos.svg/50px-GHS-pictogram-explos.svg.png) ![《全球化学品统一分类和标签制度》(简称“GHS”)中易燃物的标签图案](//upload.wikimedia.org/wikipedia/commons/thumb/6/6d/GHS-pictogram-flamme.svg/50px-GHS-pictogram-flamme.svg.png)
|
GHS提示词
|
Danger
|
H-术语
|
H228, H250, H261, H314
|
P-术语
|
P210, P231+232, P280, P303+361+353, P304+340+310, P305+351+338+310, P335+334, P422
|
若非注明,所有数据均出自标准状态(25 ℃,100 kPa)下。
|
二茂镁,有时简称 MgCp2,是一种有机镁化合物,化学式 Mg(η5-C5H5)2。它是一种主族夹心配合物,结构类似过渡金属的茂金属,由中心镁原子和两个环戊二烯配体组成。
制备
二茂镁是在1954年由恩斯特·奥托·菲舍尔和杰弗里·威尔金森独立发现的。[4][5]它可以由CpMgBr歧化或是金属镁和环戊二烯在500 °C 下反应而成。对于前者,茂基溴化镁可以由乙基溴化镁和环戊二烯反应而成,然后在220 °C 和10−4 mbar下分解成MgCp2 和MgBr2:[6]
![{\displaystyle \mathrm {Mg(C_{2}H_{5})Br\ {\xrightarrow[{-C_{2}H_{6}}]{+C_{5}H_{6},\ Et_{2}O}}\ Mg(C_{5}H_{5})Br{\xrightarrow[{-MgBr_{2}}]{x2,\ 220^{\circ }C,\ 10^{-4}mbar}}\ Mg(C_{5}H_{5})_{2}} }](https://wikimedia.org/api/rest_v1/media/math/render/svg/6a31ba05c21c56335466e339eb38fc28ad714c20)
- Et2O = 乙醚
![{\displaystyle \mathrm {Mg\ +\ 2\ C_{5}H_{6}\ {\xrightarrow[{-H_{2}}]{500^{\circ }C}}\ Mg(C_{5}H_{5})_{2}\ } }](https://wikimedia.org/api/rest_v1/media/math/render/svg/8141c8b60089ae5deb21103d070343b250162168)
在实验室里,可以由二烷基镁和环戊二烯反应得到二茂镁:[1]
![{\displaystyle \mathrm {Mg(C_{4}H_{9})_{2}\ +\ 2\ C_{5}H_{6}\ \rightarrow \ Mg(C_{5}H_{5})_{2}\ +\ 2\ C_{4}H_{10}\uparrow \ } }](https://wikimedia.org/api/rest_v1/media/math/render/svg/ed936f784dd15527d1989ea230bcd2ff411e925a)
性质
室温下,二茂镁是一种白色固体。[7]它的熔点为 176 °C,尽管在常压下会在100 °C时升华。[7]不像二茂铁,二茂镁会在极性、给电子溶剂中(例如醚和THF)会自耦电离:[8]
![{\displaystyle {\ce {MgCp2 <=> MgCp+ + Cp-}}}](https://wikimedia.org/api/rest_v1/media/math/render/svg/ec5c7c404d8b61cc86c5d0667fade5287f8a1281)
![{\displaystyle {\ce {MgCp2 + MgCp+ <=> Mg2Cp3+}}}](https://wikimedia.org/api/rest_v1/media/math/render/svg/21b6550f03e031a1e7a07091f14d161d60b84187)
![{\displaystyle {\ce {MgCp2 + Cp- <=> MgCp3-}}}](https://wikimedia.org/api/rest_v1/media/math/render/svg/0d2df2ee6c28c978bd143720fb62c793a5d96bf9)
二茂铁在标准情况下稳定,但二茂镁在氧气或湿气中迅速分解,所以在惰性气氛下制备和储存。[9]
结构和成键
通过X射线晶体学,固体二茂镁的平均 Mg-C 和C-C键长分别为2.30 Å 和1.39 Å,两个茂环是错位的,点群D5d。[10]气相电子衍射显示出相似的键长,不过两个茂环是重叠的,点群 D5h。[11][12]
关于Mg-Cp 的相互作用主要是离子键[13][14]还是共价键[11][12][15]一直存在激烈的争论。
反应性和潜在用处
二茂镁可以用来制备其它茂金属:[16]
![{\displaystyle {\ce {MgCp2 + MCl2 -> MCp2 + MgCl2}}}](https://wikimedia.org/api/rest_v1/media/math/render/svg/53526e34fe85dc7d8436b6a4989b8beb48579654)
在四氢呋喃里,二茂镁会和 MgX2(X = 卤素)交换配体,形成半夹心化合物CpMgX :[17]
![{\displaystyle {\ce {MgCp2 + MgX2 <=> 2 CpMgX}}}](https://wikimedia.org/api/rest_v1/media/math/render/svg/439bb630cb77f5a50c10ada1e34526ecb4a323c2)
反应产生的半夹心化合物可作为从有机卤化物合成取代茂基的原料。[18]
由于其高反应性,二茂镁是半导体研究中的一个有吸引力的目标,可作为化学气相沉积和掺杂应用的起始材料。[19][20]
二茂镁在下一代的镁离子电池中,有作为电解质的潜在用途。[8]
参考资料
- ^ 1.0 1.1 1.2 Anja Jaenschke: Basenaddukte des Magnesocens: Darstellung und Strukturuntersuchung von Cyclopentadienyl-, Pentamethylcyclopentadienyl- und Indenyl-Metallocenen des Magnesiums. Dissertation, Uni Hamburg, 2006 Template:URN.
- ^ W. A. Barber. Eugene G. Rochow , 编. Magnesium cyclopentadienide. McGraw-Hill Book Company, Inc. 1960: 11–15 (英语).
- ^
{{{2}}}. www.chemicalbook.com.
- ^ E. O. Fischer, W. Hafner: Cyclopentadienyl-vanadin-tetracarbonyl. In: Zeitschrift für Naturforschung B. 9, 1954, S. 503–504 (online).
- ^ G. Wilkenson, F.A. Cotton, Chem. Ind.(London) 1954, 307–308
- ^ Christoph Elschenbroich: Organometallchemie. 6. Auflage, Teubner Wiesbaden, 2008, ISBN 978-3-8351-0167-8, S. 65 (《二茂镁》在Google Books的內容。).
- ^ 7.0 7.1 Barber, W. A.; Jolly, William L., Magnesium Cyclopentadienide, Inorganic Syntheses (John Wiley & Sons, Ltd), 1960: 11–15, ISBN 9780470132371, doi:10.1002/9780470132371.ch5
- ^ 8.0 8.1 Schwarz, Rainer; Pejic, Marijana; Fischer, Philipp; Marinaro, Mario; Jörissen, Ludwig; Wachtler, Mario. Magnesocene-Based Electrolytes: A New Class of Electrolytes for Magnesium Batteries. Angewandte Chemie International Edition. 2016-11-21, 55 (48): 14958–14962. ISSN 1521-3773. PMID 27791301. doi:10.1002/anie.201606448.
- ^ Barber, W. A. A new preparation of magnesium cyclopentadienide. Journal of Inorganic and Nuclear Chemistry. 1957-01-01, 4 (5–6): 373–374. ISSN 0022-1902. doi:10.1016/0022-1902(57)80026-8.
- ^ Bünder, W.; Weiss, E. Verfeinerung der kristallstruktur von dicyclopentadienylmagnesium, (η-C5H5)2Mg [Refinement of the crystal structure of dicyclopentadienylmagnesium, (η5-C5H5)2Mg]. Journal of Organometallic Chemistry. 1975-06-10, 92 (1): 1–6. ISSN 0022-328X. doi:10.1016/S0022-328X(00)91094-5.
- ^ 11.0 11.1 Starowieyski, Kazimir B.; Brunvoll, Jon; Novak, David P.; Lusztyk, Janusz; Haaland, Arne. Molecular structures of dicyclopentadienylmagnesium and dicyclopentadienylchromium by gas-phase electron diffraction. Journal of the Chemical Society, Chemical Communications. 1974-01-01, (2): 54–55. ISSN 0022-4936. doi:10.1039/C39740000054.
- ^ 12.0 12.1 Haaland, A.; Lusztyk, J.; Brunvoll, J.; Starowieyski, K. B. On the molecular structure of dicyclopentadienylmagnesium. Journal of Organometallic Chemistry. 1975-02-11, 85 (3): 279–285. ISSN 0022-328X. doi:10.1016/S0022-328X(00)80301-0.
- ^ Cotton, F. A.; Reynolds, L. T. The Structure and Bonding of Cyclopentadienylthallium and Bis-cyclopentadienylmagnesium. Journal of the American Chemical Society. January 1958, 80 (2): 269–273. ISSN 0002-7863. doi:10.1021/ja01535a004.
- ^ Aleksanyan, V. T.; Garbuzova, I. A.; Gavrilenko, V. V.; Zakharkin, L. I. Vibrational spectra and structure of bis(cyclopentadienyl)magnesium. Journal of Organometallic Chemistry. 1977-04-12, 129 (2): 139–143. ISSN 0022-328X. doi:10.1016/S0022-328X(00)92483-5.
- ^ Lippincott, Ellis R.; Xavier, J.; Steele, D. The Vibrational Spectra and Structure of Bis-cyclopentadienylmagnesium. Journal of the American Chemical Society. 1961-05-01, 83 (10): 2262–2266. ISSN 0002-7863. doi:10.1021/ja01471a011.
- ^ Hull, H. S.; Reid, Allen Forrest; Turnbull, Alan G. Heat of formation and bond energy of bis(cyclopentadienyl)magnesium. Inorganic Chemistry. 1967-04-01, 6 (4): 805–807. ISSN 0020-1669. doi:10.1021/ic50050a032.
- ^ Ford, Warren T.; Grutzner, John B. Proton and carbon-13 nuclear magnetic resonance spectra of cyclopentadienylmagnesium compounds in tetrahydrofuran. The Journal of Organic Chemistry. 1972-08-01, 37 (16): 2561–2564. ISSN 0022-3263. doi:10.1021/jo00981a009.
- ^ Dzhemilev, U. M.; Ibragimov, A. G.; Tolstikov, G. A. Synthesis and transformations of "non-grignard" organomagnesium reagents obtained from 1,3-dienes. Journal of Organometallic Chemistry. 1991-03-26, 406 (1–2): 1–47. ISSN 0022-328X. doi:10.1016/0022-328X(91)83169-5.
- ^ Lundberg, Å; Andersson, S. G.; Landgren, G.; Rask, M. Abruptp- type doping transitions using bis-(cyclopentadienyl)-magnesium in metal-organic vapor phase epitaxy of GaAs. Journal of Electronic Materials. 1988-07-01, 17 (4): 311–314. Bibcode:1988JEMat..17..311R. ISSN 1543-186X. S2CID 97230793. doi:10.1007/BF02652111.
- ^ Kondo, M.; Anayama, C.; Sekiguchi, H.; Tanahashi, T. Mg-doping transients during metalorgic vapor phase epitaxy of GaAs and AlGaInP. Journal of Crystal Growth. 1994-08-01, 141 (1–2): 1–10. Bibcode:1994JCrGr.141....1K. ISSN 0022-0248. doi:10.1016/0022-0248(94)90085-X.
|
|