Difference between revisions 6001716 and 6001717 on simplewiki

{{chembox
| Verifiedfields = changed
| verifiedrevid = 457631192
| ImageFileL1 = Ferrocene.svg
| ImageSizeL1 = 80 px
| ImageFileR1 = Ferrocene-from-xtal-3D-balls.png
| ImageSizeR1 = 120 px
| ImageFileL2 = Ferrocene 3d model 2.png
(contracted; show full)
| Appearance = light orange powder
| Density = 1.107 g/cm<sup>3</sup> (0°C), 1.490 g/cm<sup>3</sup> (20 °C)<ref>{{cite web|url=http://www.chemicalbook.com/ProductMSDSDetailCB1414721_EN.htm|title=Ferrocene(102-54-5)|accessdate=3 February 2010}}</ref>
| MeltingPt = 172.5 °C<ref>{{RubberBible86th|page=3.258}}</ref>
| BoilingPt = 249 °C
| Solubility = Insoluble in water, soluble in most organic solvents
 }}
| Section3 = {{Chembox Hazards
| MainHazards =
  
| FlashPt =  
| Autoignition =  
 }}
| Section8 = {{Chembox Related
| OtherCpds = [[cobaltocene]], [[nickelocene]], [[chromocene]], [[ruthenocene]], [[plumbocene]]}}
}}

'''Ferrocene''' is an [[Organometallic chemistry|organometallic compound]] with the formula Fe(C<sub>5</sub>H<sub>5</sub>)<sub>2</sub>. It is the prototypical [[metallocene]], a type of [[organometallic chemistry|organometallic]] [[chemistry|chemical]] compound consisting of two [[cyclopentadienyl complex|cyclopentadienyl]] rings bound on opposite sides of a central [[metal]] atom. Such organometallic compounds are also known as [[sandwich compound]]s.<ref>{{cite journal|doi = 10.1002/chin.200443242|title = Ferrocene: 50 Years of Transition Metal Organometallic Chemistry&nbsp;—– From Organic and Inorganic to Supramolecular Chemistry|year = 2004|last1 = Federman Neto|first1 = Alberto|last2 = Pelegrino|first2 = Alessandra Caramori|last3 = Darin|first3 = Vitor Andre|journal = ChemInform|volume = 35|issue = 43}}</ref><ref>{{cite journal|author=Pauson, P. L.|title=Ferrocene-how it all began|journal=[[Journal of Organometallic Chemistry|J. Organomet. Chem.]]|year=2001|pages=637–639|volume = 637–639|doi = 10.1016/S0022-328X(01)01126-3}}</ref> The rapid growth of [[organometallic chemistry]] is often attributed to the excitement arising from the discovery of ferrocene and its many [[Structural analog|analogues]]s.

==History==
[[File:Ferrocene kealy.svg|thumb|left|Pauson and Kealy's original (incorrect) notion of ferrocene's molecular structure<ref name = "Pauson_Kealy" />]]
Ferrocene was first prepared unintentionally. In 1951, Pauson and Kealy at [[Duquesne University]] reported the reaction of cyclopentadienyl magnesium bromide and [[iron(III) chloride|ferric chloride]] with the goal of oxidatively coupling the diene to prepare [[fulvalene]]. Instead, they obtained a light orange powder of "remarkable stability.".<ref name = "Pauson_Kealy">{{cite journal|first1 = T. J.|last1 = Kealy|first2 = P. L.|last2 = Pauson|title = A New Type of Organo-Iron Compound|journal = [[Nature (journal)|Nature]]|year = 1951|volume = 168|pages = 1039|doi = 10.1038/1681039b0 |issue = 4285|bibcode = 1951Natur.168.1039K}}</ref>  
A second group at [[British Oxygen]] also unknowingly discovered ferrocene. Miller, Tebboth and Tremaine were trying to synthesise amines from hydrocarbons such as cyclopentadiene and ammonia in a modification of the [[Haber process]]. They published this result in 1952 although the actual work was done three years earlier <ref>{{cite journal| author=Miller, S. A., Tebboth, J. A., Tremaine, J. F.|journal= [[Journal of the Chemical Society|J. Chem. Soc.]]|year=1952| pages= 632–635| title=114. Dicyclop(contracted; show full)ume=171 |pages= 121–122|doi = 10.1038/171121a0|issue=4342}}</ref><ref>{{cite journal |author = J. Dunitz, L. Orgel, A. Rich |title = The crystal structure of ferrocene |journal = [[Acta Crystallographica]] |year = 1956 |volume = 9 |pages = 373–375 |doi = 10.1107/S0365110X56001091 |issue = 4}}</ref><ref>{{cite journal|author=P. F. Eiland and R. Pepinsky |year=1952|title=X-ray examination of iron biscyclopentadienyl|journal=Journal of the American Chemical Society|volume=74|page =4971
|doi=10.1021/ja01139a527|issue=19}}</ref> Its distinctive "sandwich" structure led to an explosion of interest in compounds of [[d-block]] metals with hydrocarbons, and invigorated the development of the flourishing study of organometallic chemistry. In 1973 [[Ernst Otto Fischer|Fischer]] of the [[Technische Universität München]] and [[Geoffrey Wilkinson|Wilkinson]] of [[Imperial College London]] shared a Nobel Prize for their work on metallocenes and other aspects of organometallic chemistry.<ref>{{cite web |url=http://nobelprize.org/nobel_prizes/chemistry/laureates/1973/press.html |title= Press Release: The Nobel Prize in Chemistry 1973 |year= 1973 |publisher= The Royal Swedish Academy of Sciences}}</ref>

==Structure and bonding==
The carbon-carbon bond distances are 1.40 Å within the five membered rings, and the Fe-C bond distances are 2.04 Å.  Although [[X-ray crystallography]] (in the monoclinic space group) points to the Cp rings being in a staggered conformation, it has been shown through gas phase electron diffraction<ref>Haaland, A.; Nilsson, J. E. "The Determination of Barriers to Internal Rotation by Means of Electron Diffraction. Ferrocene and Ruthenocene" Acta Chemica Scandinavica 1968, volume 22, pp. 2653-–2670. {{DOI|10.3891/acta.chem.scand.22-2653}}</ref> and computational studies<ref>Sonia Coriani, Arne Haaland, Trygve Helgaker, Poul Jørgensen "The Equilibrium Structure of Ferrocene" ChemPhysChem 2006, Volume 7, pages 245–249. {{doi|10.1002/cphc.200500339}}</ref> that in the gas phase the Cp rings are eclipsed. The staggered conformation is believed to be most stable in the condensed phase due to crystal packing.

(contracted; show full)

:FeCl<sub>2</sub> + Mn(C<sub>5</sub>H<sub>5</sub>)<sub>2</sub> → MnCl<sub>2</sub> + Fe(C<sub>5</sub>H<sub>5</sub>)<sub>2</sub>

As expected for a symmetric and uncharged species, ferrocene is soluble in normal organic solvents, such as benzene, but is insoluble in water. Ferrocene is an [[air]]-stable orange solid that readily [[Sublimation (phase transition)|sublime
s]]s, especially upon heating in a vacuum. It is stable to temperatures as high as 400 °C.<ref>Solomons, Graham, and Craig Fryhle. Organic Chemistry. 9th ed. USA: John Wiley & Sons, Inc., 2006.</ref> The following table gives typical values of vapor pressure of ferrocene at different temperatures:<ref>{{cite journal|doi=10.1021/je050502y|title=New Static Apparatus and Vapor Pressure of Reference Materials: Naphthalene, Benzoic Acid, Benzophenone, and Ferrocene|year=2006|last1=Monte|first1=Manuel J. S.|last2=Santos|first2=Luís M. N. B. F.|last3=Fulem|first3=Michal|last4=Fonseca|first4=José M. S.|last5=Sousa|first5=Carlos A. D.|journal=Journal of Chemical & Engineering Data|volume=51|page=757|issue=2}}</ref>

{| class="wikitable"
|-
! Pressure (Pa)
! 1
! 10
! 100
|-
| Temperature (K)
| 298
| 323
| 353
|}

==Reactions==
⏎
⏎
===With electrophiles===
Ferrocene undergoes many reactions characteristic of aromatic compounds, enabling the preparation of substituted derivatives. A common undergraduate experiment is the [[Friedel-Crafts reaction]] of ferrocene with [[acetic anhydride]] (or [[acetyl chloride]]) in the presence of [[phosphoric acid]] as a catalyst.
[[Image:FcGen'l.png|400px|thumb|center|Important reactions of ferrocene with electrophiles and other reagents.]]

===Lithiation===
(contracted; show full)for an Antiproliferative Effect of Hydroxyferrocifens on both Hormone-Dependent and Hormone-Independent Breast Cancer Cell Lines| journal=Chemistry, a European Journal| year=2003| volume=9| pages=5223–36|pmid=14613131|doi=10.1002/chem.200305024|issue=21}}</ref><ref>{{cite journal|journal=[[Chemical and Engineering News]]|date=16 September 2002| title= The Bio Side of Organometallics|author= Ron Dagani| volume = 80| issue= 37| pages = 23–29| url=http://pubs.acs.org/cen/science/8037/8037sci1.html
|doi=10.1021/cen-v080n037.p023}}</ref><ref>{{cite journal |author=S. Top, B. Dauer, J. Vaissermann and G. Jaouen| journal=[[Journal of Organometallic Chemistry]]| title= Facile route to ferrocifen, 1-[4-(2-dimethylaminoethoxy)]-1-(phenyl-2-ferrocenyl-but-1-ene), first organometallic analogue of tamoxifen, by the McMurry reaction|doi=10.1016/S0022-328X(97)00086-7 |year=1997| volume=541| pages= 355–361}}</ref>

===Materials chemistry===
(contracted; show full)
Chiral ferrocenyl [[phosphine]]s are employed as ligands for transition-metal catalyzed reactions. Some of them have found industrial applications in the synthesis of pharmaceuticals and agrochemicals. For example, the [[diphosphines|diphosphine]] [[1,1'-bis(diphenylphosphino)ferrocene]] (dppf) is a valuable ligand for [[palladium]]-[[coupling reaction]]s.

==Derivatives and variations==
Ferrocene analogues can be prepared with variants of cyclopentadienyl. For example, bis[[indene|indenyl
]]iron]] and bisfluorenyliron.<ref name=Stepnicka/>

[[Image:FcVarietyPack.png|400px|center|Various ferrocene derivatives where cyclopentadienyl has been replaced by related ligands]]

(contracted; show full)
{{commons category|ferrocene}}

[[Category:Organoiron compounds]]
[[Category:Metallocenes]]
[[Category:Antiknock agents]]
[[Category:Sandwich compounds]]
[[Category:Cyclopentadienyl complexes]]