Wikipedia:WikiProject Chemicals/Chembox validation/VerifiedDataSandbox and Tetracyanoethylene: Difference between pages

{{short description|Organic compound with formula C2(CN)4}}

|Watchedfields = changed

|verifiedrevid = 470603691

|Name = Tetracyanoethylene

|ImageFileL1 =Tetracyanoethylene.png

|ImageFileR1 = TCNE3D.png

|ImageSizeR1 = 150px

|ImageNameR1 = tetracyanoethylene

|ImageFile2 = TCNEpowder.jpg

|PIN = Ethenetetracarbonitrile

|OtherNames = TCNE

|Section1={{Chembox Identifiers

|ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}

|ChemSpiderID = 12114

|PubChem = 12635

|InChI = 1/C6N4/c7-1-5(2-8)6(3-9)4-10

|InChIKey = NLDYACGHTUPAQU-UHFFFAOYAN

|StdInChI_Ref = {{stdinchicite|correct|chemspider}}

|StdInChI = 1S/C6N4/c7-1-5(2-8)6(3-9)4-10

|StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}

|StdInChIKey = NLDYACGHTUPAQU-UHFFFAOYSA-N

|CASNo_Ref = {{cascite|correct|CAS}}

|CASNo = 670-54-2

|UNII_Ref = {{fdacite|correct|FDA}}

|UNII = C592309ECU

|SMILES = N#CC(C#N)=C(C#N)C#N

|Section2={{Chembox Properties

|Formula = {{chem2|C2(CN)4}}

|C=6|N=4

|Density = 1.35 g/cm³

|MeltingPtC = 199

|BoilingPtC = 130 to 140

|BoilingPt_notes = 0.1 [[mmHg]] ([[Sublimation (chemistry)|sublimes]])<ref name=Carboni>{{OrgSynth | journal=Org. Synth.|author = Carboni, R. A. | title = Tetracyanoethylene | volume = 39 | pages = 64 | year = 1959 | doi = 10.15227/orgsyn.039.0064}}</ref>

}}

'''Tetracyanoethylene''' ('''TCNE''') is [[organic compound]] with the formula {{chem2|C2(CN)4}}. It is a colorless solid, although samples are often off-white. It is an important member of the [[cyanocarbon]]s.

==Synthesis and reactions==

TCNE is prepared by [[bromination|brominating]] [[malononitrile]] in the presence of [[potassium bromide]] to give the KBr-complex, and dehalogenating with [[copper]].<ref name=Carboni/>

Oxidation of TCNE with [[hydrogen peroxide]] gives the corresponding [[epoxide]], which has unusual properties.<ref name=linn73>{{OrgSynth | author = Linn, W. J. | title = Tetracyanoethylene Oxide | volume = 49 | pages = 103 | year =1969 | doi = 10.15227/orgsyn.049.0103}}</ref>

In the presence of [[Base (chemistry)|base]], TCNE reacts with [[malononitrile]] to give [[Salt (chemistry)|salt]]s of pentacyanopropenide:<ref>{{cite journal |first1= W. J.|last1=Middleton|first2=D. W.|last2=Wiley|doi=10.15227/orgsyn.041.0099|title=Tetramethylammonium 1,1,2,3,3-Pentacyanopropenide

|journal=Org. Synth.|year=1961|volume=41|page=99}}</ref>

:{{chem2|C2(CN)4 + CH2(CN)2 → [(NC)2C\dC(CN)\sC(CN)2]- + CN- + 2 H+}}

==Redox chemistry==

TCNE is an [[electron acceptor]]. Cyano groups have low energy [[Pi bond|π* orbitals]], and the presence of four such groups, with their [[Conjugated system|π systems]] (conjugated) to the central {{chem2|C\dC}} [[double bond]], gives rise to an electrophilic [[alkene]]. TCNE is [[Redox|reduced]] at −0.27&nbsp;V vs ferrocene/[[ferrocenium]]:<ref name=Geiger>{{cite journal|first1=N. G.|last1= Connelly|first2= W. E.|last2= Geiger| title=Chemical Redox Agents for Organometallic Chemistry|journal=Chemical Reviews|year= 1996| volume= 96|issue=2| pages= 877–910| doi=10.1021/cr940053x| pmid=11848774}}</ref>

:{{chem2|C2(CN)4 + e- → [C2(CN)4]-}}

Because of its ability to accept an electron, TCNE has been used to prepare numerous [[charge-transfer salt]]s.<ref name=chittipeddi87>{{cite journal | last1=Chittipeddi | first1=Sailesh | last2=Cromack | first2=K. R. | last3=Miller | first3=Joel S. | last4=Epstein | first4=A. J. | title=Ferromagnetism in Molecular Decamethylferrocenium Tetracyanoethenide (DMeFc TCNE) | journal=Physical Review Letters | volume=58 | issue=25 | date=1987-06-22 | issn=0031-9007 | doi=10.1103/physrevlett.58.2695 | pages=2695–2698| pmid=10034821 | bibcode=1987PhRvL..58.2695C}}</ref>

The central C=C distance in TCNE is 135 [[picometre|pm]].<ref>{{cite journal |doi=10.1021/ja00804a010 |title=Valence electron distribution in cubic tetracyanoethylene by the combined use of x-ray and neutron diffraction |date=1973 |last1=Becker |first1=P. |last2=Coppens |first2=P. |last3=Ross |first3=F. K. |journal=Journal of the American Chemical Society |volume=95 |issue=23 |pages=7604–7609 }}</ref> Upon reduction, this bond elongates to 141–145 pm, depending on the counterion.<ref>{{cite journal |doi=10.1021/ic00050a032 |title=Structures of charge-perturbed or sterically overcrowded molecules. 16. The cesium tetracyanoethylenide radical salt |date=1992 |last1=Bock |first1=H. |last2=Ruppert |first2=K. |journal=Inorganic Chemistry |volume=31 |issue=24 |pages=5094–5099 }}</ref>

==Safety==

TCNE hydrolyzes in moist air to give [[hydrogen cyanide]] and should be handled accordingly.<ref name = Carboni/>

==References==

{{reflist}}

[[Category:Alkene derivatives]]

[[Category:Nitriles]]

[[Category:Superconductors]]