查看“︁二茂镁”︁的源代码

{{Chembox
|ImageFile=Magnesocene.svg
|ImageAlt=Structure of magnesocene
|ImageSize=100px
|ImageName=
|IUPACName=bis(''η''<sup>5</sup>-cyclopentadienyl)magnesium
|Section1={{Chembox Identifiers
| CASNo = 1284-72-6
| CASNo_Ref = {{cascite|correct|CAS}}
| PubChem = 11984632
| ChemSpiderID = 10628001
| EINECS =  603-275-0
| InChI=1S/2C5H5.Mg/c2*1-2-4-5-3-1;/h2*1-5H;/q2*-1;+2
| SMILES=[cH-]1cccc1.[cH-]1cccc1.[Mg+2]
}}
|Section2={{Chembox Properties
|Mg=1|C=10|H=10
|Appearance=无色晶体<ref name="Jaenschke">Anja Jaenschke: ''Basenaddukte des Magnesocens: Darstellung und Strukturuntersuchung von Cyclopentadienyl-, Pentamethylcyclopentadienyl- und Indenyl-Metallocenen des Magnesiums''. Dissertation, Uni Hamburg, 2006 {{URN|nbn|de:gbv:18-30786}}.</ref>
|MeltingPtC=176
|Melting_notes=<ref name="IS6">{{cite book| author=W. A. Barber| title=Magnesium cyclopentadienide| editor=Eugene G. Rochow| publisher=McGraw-Hill Book Company, Inc.| date=1960| language=en| pages=11–15}}</ref>
|BoilingPtC=290
|Boiling_notes=<ref name="Chemicalbook">{{ChemicalBook|7494611|name=Bis(cyclopentadienyl)magnesium|Abruf=2011-12-30}}</ref>
|SolubleOther=与水激烈反应，可溶于极性和非极性溶剂。<ref name = "Jaenschke"/>
}}
|Section7 = {{Chembox Hazards
| ExternalSDS = [https://www.ereztech.com/wp-content/uploads/chemical_sds/SDS-MG4726.pdf External SDS]
| GHSPictograms = {{GHS01}}{{GHS02}}{{GHS05}}
| GHSSignalWord = Danger
| HPhrases = {{H-phrases|228|250|261|314 }}
| PPhrases = {{P-phrases|210|231+232|280|303+361+353|304+340+310|305+351+338+310|335+334|422 }}
}}
}}
'''二茂镁'''，有时简称 MgCp<sub>2</sub>，是一种[[有机镁化合物]]，化学式 Mg(η<sup>5</sup>-C<sub>5</sub>H<sub>5</sub>)<sub>2</sub>。它是一种[[主族元素|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。<ref>{{ZNaturforsch |Serie=B |Autor=E. O. Fischer, W. Hafner |Titel=Cyclopentadienyl-vanadin-tetracarbonyl |Jahr=1954 |Startseite=503 |Endseite=504 |URL=https://zfn.mpdl.mpg.de/data/Reihe_B/9/ZNB-1954-9b-0503_n.pdf }}</ref><ref>G. Wilkenson, F.A. Cotton, Chem. Ind.(London) 1954, 307–308</ref>它可以由CpMgBr歧化或是金属[[镁]]和[[环戊二烯]]在500&nbsp;°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&nbsp;°C 和10<sup>−4</sup>&nbsp;[[毫巴|mbar]]下分解成MgCp<sub>2</sub> 和MgBr<sub>2</sub>：<ref name="Elschenbroich_65">Christoph Elschenbroich: ''Organometallchemie.'' 6. Auflage, Teubner Wiesbaden, 2008, ISBN 978-3-8351-0167-8, S. 65 ({{Google Buch |BuchID=wtuuzCfNTCcC |Seite=65}}).</ref>

:<math>\mathrm{ Mg(C_2H_5)Br\  \xrightarrow[- C_2H_6]{+ C_5H_6,\ Et_2O} \  Mg(C_5H_5)Br \xrightarrow[- MgBr_2]{x2,\ 220^\circ C,\ 10^ {-4} mbar} \  Mg(C_5H_5)_2}</math>
:<small>Et<sub>2</sub>O = [[乙醚]]</small>

:<math>\mathrm{ Mg\ +\ 2\ C_5H_6\ \xrightarrow[- H_2]{500^\circ C} \  Mg(C_5H_5)_2 \ }</math>

在实验室里，可以由二烷基镁和[[环戊二烯]]反应得到二茂镁：<ref name = "Jaenschke"/>

:<math>\mathrm{ Mg(C_4H_9)_2\ +\ 2\ C_5H_6\ \rightarrow \  Mg(C_5H_5)_2 \ +\ 2\ C_4H_{10} \uparrow \  }</math>

== 性质==
室温下，二茂镁是一种白色固体。<ref name="Barber 1960">{{Citation|last1=Barber|first1=W. A.|title=Magnesium Cyclopentadienide|date=1960|work=Inorganic Syntheses|pages=11–15|publisher=John Wiley & Sons, Ltd|doi=10.1002/9780470132371.ch5|isbn=9780470132371|last2=Jolly|first2=William L.}}</ref>它的熔点为 176&nbsp;°C，尽管在常压下会在100&nbsp;°C时升华。<ref name="Barber 1960" />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：<ref name="Schwarz 2016">{{Cite journal|last1=Schwarz|first1=Rainer|last2=Pejic|first2=Marijana|last3=Fischer|first3=Philipp|last4=Marinaro|first4=Mario|last5=Jörissen|first5=Ludwig|last6=Wachtler|first6=Mario|date=2016-11-21|title=Magnesocene-Based Electrolytes: A New Class of Electrolytes for Magnesium Batteries|journal=Angewandte Chemie International Edition|volume=55|issue=48|pages=14958–14962|doi=10.1002/anie.201606448|pmid=27791301|issn=1521-3773}}</ref>

:<chem>MgCp2 <=> MgCp+ + Cp-</chem>

:<chem>MgCp2 + MgCp+ <=> Mg2Cp3+</chem>

:<chem>MgCp2 + Cp- <=> MgCp3-</chem>

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。<ref>{{Cite journal|last=Barber|first=W. A.|date=1957-01-01|title=A new preparation of magnesium cyclopentadienide|journal=Journal of Inorganic and Nuclear Chemistry|volume=4|issue=5–6|pages=373–374|doi=10.1016/0022-1902(57)80026-8|issn=0022-1902}}</ref>

== 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D<sub>5d</sub>。<ref>{{Cite journal|last1=Bünder|first1=W.|last2=Weiss|first2=E.|date=1975-06-10|title=Verfeinerung der kristallstruktur von dicyclopentadienylmagnesium, (η-C5H5)2Mg [Refinement of the crystal structure of dicyclopentadienylmagnesium, (η5-C5H5)2Mg]|journal=Journal of Organometallic Chemistry|volume=92|issue=1|pages=1–6|doi=10.1016/S0022-328X(00)91094-5|issn=0022-328X}}</ref>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 D<sub>5h</sub>。<ref name="Starowieyski 1974">{{Cite journal|last1=Starowieyski|first1=Kazimir B.|last2=Brunvoll|first2=Jon|last3=Novak|first3=David P.|last4=Lusztyk|first4=Janusz|last5=Haaland|first5=Arne|date=1974-01-01|title=Molecular structures of dicyclopentadienylmagnesium and dicyclopentadienylchromium by gas-phase electron diffraction|journal=Journal of the Chemical Society, Chemical Communications|issue=2|pages=54–55|doi=10.1039/C39740000054|issn=0022-4936}}</ref><ref name="Haaland 1975">{{Cite journal|last1=Haaland|first1=A.|last2=Lusztyk|first2=J.|last3=Brunvoll|first3=J.|last4=Starowieyski|first4=K. B.|date=1975-02-11|title=On the molecular structure of dicyclopentadienylmagnesium|journal=Journal of Organometallic Chemistry|volume=85|issue=3|pages=279–285|doi=10.1016/S0022-328X(00)80301-0|issn=0022-328X}}</ref>

关于Mg-Cp 的相互作用主要是[[离子键]]<ref>{{Cite journal|last1=Cotton|first1=F. A.|last2=Reynolds|first2=L. T.|date=January 1958|title=The Structure and Bonding of Cyclopentadienylthallium and Bis-cyclopentadienylmagnesium|journal=Journal of the American Chemical Society|volume=80|issue=2|pages=269–273|doi=10.1021/ja01535a004|issn=0002-7863}}</ref><ref>{{Cite journal|last1=Aleksanyan|first1=V. T.|last2=Garbuzova|first2=I. A.|last3=Gavrilenko|first3=V. V.|last4=Zakharkin|first4=L. I.|date=1977-04-12|title=Vibrational spectra and structure of bis(cyclopentadienyl)magnesium|journal=Journal of Organometallic Chemistry|volume=129|issue=2|pages=139–143|doi=10.1016/S0022-328X(00)92483-5|issn=0022-328X}}</ref>还是[[共价键]]<ref name="Starowieyski 1974" /><ref name="Haaland 1975" /><ref>{{Cite journal|last1=Lippincott|first1=Ellis R.|last2=Xavier|first2=J.|last3=Steele|first3=D.|date=1961-05-01|title=The Vibrational Spectra and Structure of Bis-cyclopentadienylmagnesium|journal=Journal of the American Chemical Society|volume=83|issue=10|pages=2262–2266|doi=10.1021/ja01471a011|issn=0002-7863}}</ref>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：<ref>{{Cite journal|last1=Hull|first1=H. S.|last2=Reid|first2=Allen Forrest|last3=Turnbull|first3=Alan G.|date=1967-04-01|title=Heat of formation and bond energy of bis(cyclopentadienyl)magnesium|journal=Inorganic Chemistry|volume=6|issue=4|pages=805–807|doi=10.1021/ic50050a032|issn=0020-1669}}</ref>
:<chem>MgCp2 + MCl2 -> MCp2 + MgCl2</chem>

在四氢呋喃里，二茂镁会和 MgX<sub>2</sub>（X = [[卤素]]）交换配体，形成半夹心化合物CpMgX ：<ref>{{Cite journal|last1=Ford|first1=Warren T.|last2=Grutzner|first2=John B.|date=1972-08-01|title=Proton and carbon-13 nuclear magnetic resonance spectra of cyclopentadienylmagnesium compounds in tetrahydrofuran|journal=The Journal of Organic Chemistry|volume=37|issue=16|pages=2561–2564|doi=10.1021/jo00981a009|issn=0022-3263}}</ref>

:<chem>MgCp2 + MgX2 <=> 2 CpMgX</chem>
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。<ref name="Dzhemilev 1991">{{Cite journal|last1=Dzhemilev|first1=U. M.|last2=Ibragimov|first2=A. G.|last3=Tolstikov|first3=G. A.|date=1991-03-26|title=Synthesis and transformations of "non-grignard" organomagnesium reagents obtained from 1,3-dienes|journal=Journal of Organometallic Chemistry|volume=406|issue=1–2|pages=1–47|doi=10.1016/0022-328X(91)83169-5|issn=0022-328X}}</ref>

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_(半导体)|掺杂]]应用的起始材料。<ref>{{Cite journal|last1=Lundberg|first1=Å|last2=Andersson|first2=S. G.|last3=Landgren|first3=G.|last4=Rask|first4=M.|date=1988-07-01|title=Abruptp- type doping transitions using bis-(cyclopentadienyl)-magnesium in metal-organic vapor phase epitaxy of GaAs|journal=Journal of Electronic Materials|volume=17|issue=4|pages=311–314|doi=10.1007/BF02652111|issn=1543-186X|bibcode=1988JEMat..17..311R|s2cid=97230793}}</ref><ref>{{Cite journal|last1=Kondo|first1=M.|last2=Anayama|first2=C.|last3=Sekiguchi|first3=H.|last4=Tanahashi|first4=T.|date=1994-08-01|title=Mg-doping transients during metalorgic vapor phase epitaxy of GaAs and AlGaInP|journal=Journal of Crystal Growth|volume=141|issue=1–2|pages=1–10|doi=10.1016/0022-0248(94)90085-X|issn=0022-0248|bibcode=1994JCrGr.141....1K}}</ref>

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。<ref name="Schwarz 2016" />

==参考资料==
{{reflist}}
{{镁化合物}}
{{茂金属}}

[[Category:茂金属]]
[[Category:镁化合物]]
[[Category:夹心化合物]]
[[Category:1950年代发现的物质]]
[[Category:茂基配合物]]