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Revision as of 06:55, 11 August 2011 editBeetstra (talk | contribs)Edit filter managers, Administrators172,031 edits Script assisted update of identifiers for the Chem/Drugbox validation project (updated: 'ChEBI', 'StdInChI').← Previous edit Latest revision as of 04:00, 11 February 2024 edit undoMaxim Masiutin (talk | contribs)Extended confirmed users, IP block exemptions, Pending changes reviewers30,619 edits Added bibcode. | Use this bot. | #UCB_Other 
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{{Short description|Organic compound with formula C12H4N4}}
{{chembox {{chembox
| Watchedfields = changed
| verifiedrevid = 439958202
| Name = Tetracyanoquinodimethane (TCNQ) | verifiedrevid = 444218213
| Name = Tetracyanoquinodimethane (TCNQ)
| ImageFileL1 = Tetracyanoquinodimethane Formula V.1.svg
| ImageFile = TCNQ.png
| ImageSize = 100px | ImageSizeL1 = 110px
| ImageFileR1 = Tetracyanoquinodimethane 3D ball.png
| ImageName =
| ImageSizeR1 = 120
⚫ | OtherNames = (2,5-Cyclohexadiene-1,4-diylidene)<br/>-dimalononitrile, 7,7,8,8-Tetracyanoquinodimethane
| ImageAltR1 = Ball-and-stick model of the tetracyanoquinodimethane molecule
⚫ | Section1 = {{Chembox Identifiers
| ImageFile2 = TCNQsample.jpg
⚫ | CASNo_Ref = {{cascite}}
| ImageSize2 = 240px
| ImageCaption2 = Sample of TCNQ
| PIN = 2,2′-(Cyclohexa-2,5-diene-1,4-diylidene)dipropanedinitrile
⚫ | OtherNames = (2,5-Cyclohexadiene-1,4-diylidene)<br/>-dimalononitrile, 7,7,8,8-Tetracyanoquinodimethane
⚫ |Section1={{Chembox Identifiers
⚫ | CASNo_Ref = {{cascite|correct|CAS}}
| CASNo = 1518-16-7 | CASNo = 1518-16-7
| ChEBI_Ref = {{ebicite|correct|EBI}}
⚫ | PubChem = 73697
| ChEBI = 52445
| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}} | ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
| ChemSpiderID = 66342 | ChemSpiderID = 66342
| ChEBI = 52445 | EINECS = 216-174-8
⚫ | PubChem = 73697
| UNII_Ref = {{fdacite|correct|FDA}}
| UNII = HC6FB4H2KW
| StdInChI_Ref = {{stdinchicite|correct|chemspider}}
| StdInChI = 1S/C12H4N4/c13-5-11(6-14)9-1-2-10(4-3-9)12(7-15)8-16/h1-4H | StdInChI = 1S/C12H4N4/c13-5-11(6-14)9-1-2-10(4-3-9)12(7-15)8-16/h1-4H
⚫ | InChI = 1S/C12H4N4/c13-5-11(6-14)9-1-2-10(4-3-9)12(7-15)8-16/h1-4H
⚫ | SMILES = c1cc(=C(C#N)C#N)ccc1=C(C#N)C#N
⚫ | InChI = 1S/C12H4N4/c13-5-11(6-14)9-1-2-10(4-3-9)12(7-15)8-16/h1-4H
| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}} | StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}
| StdInChIKey = PCCVSPMFGIFTHU-UHFFFAOYSA-N | StdInChIKey = PCCVSPMFGIFTHU-UHFFFAOYSA-N
⚫ | SMILES = c1cc(=C(C#N)C#N)ccc1=C(C#N)C#N
}} }}
| Section2 = {{Chembox Properties |Section2={{Chembox Properties
| C=12|H=4|N=4
| Formula = C<sub>12</sub>H<sub>4</sub>N<sub>4</sub>
⚫ | Appearance = green colored powder or orange crystals
| MolarMass = 204.19 g/mol
| Density =
⚫ | Appearance = green-coloured crystals
| Density = | MeltingPtC = 293.5 to 296
| BoilingPt = ]
| MeltingPt = 293.5-296 °C
| BoilingPt = sublimes | Solubility =
| Solubility =
}} }}
| Section3 = {{Chembox Structure |Section7={{Chembox Hazards
| GHS_ref=<ref>{{cite web |title=7,7,8,8-Tetracyanoquinodimethane |url=https://pubchem.ncbi.nlm.nih.gov/compound/73697#section=Safety-and-Hazards |website=pubchem.ncbi.nlm.nih.gov |access-date=16 December 2021 |language=en}}</ref>
| CrystalStruct =
| GHSPictograms = {{GHS06}}{{GHS07}}
}}
| GHSSignalWord = Danger
| ]
| HPhrases = {{H-phrases|302|311|312|331}}
| organic solvents
| PPhrases = {{P-phrases|261|264|270|271|280|301+310|301+312|302+352|304+312|304+340|311|312|321|322|330|361|363|403+233|405|501}}
|-
| ]
|
|-
| ]
|
|-
| Section7 = {{Chembox Hazards
| EUClass = not listed
}} }}
}} }}


'''Tetracyanoquinodimethane''' (TCNQ) is the ] with the formula (NC)<sub>2</sub>CC<sub>6</sub>H<sub>4</sub>C(CN)<sub>2</sub>. This relative of ] is an electron-acceptor that is used to prepare ] salts, which are of interest in the area of ]. '''Tetracyanoquinodimethane''' ('''TCNQ''') is an ] with the ] {{chem2|(N\tC\s)2C\dC6H4\dC(\sC\tN)2}}. It is an orange ] solid. This ], a relative of ], is an ] that is used to prepare ] salts, which are of interest in ].


==Preparation and use== ==Preparation and structure==
TCNQ is prepared by the condensation of ] with ], followed by dehydrogenation of the resulting diene with ]:<ref>"Substituted Quinodimethans. I. Preparation and Chemistry of 7,7,8,8-Tetracyanoquinodimethan" J. Am. Chem. Soc. 1962, Volume 84, pp. 3370-3374. {{DOI|10.1021/ja00876a028}}</ref> TCNQ is prepared by the ] of ] with ], followed by ] of the resulting diene with ]:<ref>{{cite journal|title=Substituted Quinodimethans. I. Preparation and Chemistry of 7,7,8,8-Tetracyanoquinodimethan|journal=Journal of the American Chemical Society|volume=84|issue=17|pages=3370|doi=10.1021/ja00876a028|year=1962|last1=Acker|first1=Donald S.|last2=Hertler|first2=Walter R.}}</ref>
:{{chem2|C6H8O2 + 2 CH2(CN)2 → C6H8(C(CN)2)2 + 2 H2O}}
:C<sub>6</sub>H<sub>8</sub>O<sub>2</sub> + 2 CH<sub>2</sub>(CN)<sub>2</sub> → C<sub>6</sub>H<sub>8</sub>(C(CN)<sub>2</sub>)<sub>2</sub> + 2 H<sub>2</sub>O
:C<sub>6</sub>H<sub>8</sub>(C(CN)<sub>2</sub>)<sub>2</sub> + 2 Br<sub>2</sub> → C<sub>6</sub>H<sub>4</sub>(C(CN)<sub>2</sub>)<sub>2</sub> + 4 ] :{{chem2|C6H8(C(CN)2)2 + 2 Br2 → C6H4(C(CN)2)2 + 4 ]}}


The molecule is planar, with D<sub>2h</sub> ].<ref>{{cite journal|author1=Long, Robert E. |author2=Sparks, Robert A. |author3=Trueblood, Kenneth N. |title=The crystal and molecular structure of 7,7,8,8-tetracyanoquinodimethane|journal=Acta Crystallographica|volume=18|issue=5|pages=932|doi=10.1107/S0365110X65002256|year=1965|doi-access=free|bibcode=1965AcCry..18..932L }}</ref>
Like ], TCNQ is easily reduced electrochemically to give a blue-coloured radical anion. Upon treatment with the electron donor ] (TTF), it forms the “organic metal” TTF-TCNQ where the TCNQ is the acceptor. This salt crystallizes as a one-dimensional polymer, consisting of segregated stacks of cations and anions of the donors and the acceptors, respectively.

==Reactions==
Like ] (TCNE), TCNQ is easily ] to give a blue-coloured ] ]. The ] is about −0.3 ] relative to the ]/] couple. This property is exploited in the development of ]s. TCNQ also forms complexes with ] ]es.{{cln|reason="electron rich metal complexes"... Electron-rich in regards of what? Please explain this jargon in more details.|date=August 2023}}<ref>{{cite journal|author1=Kaim, Wolfgang |author2=Moscherosch, Michael |title=The coordination chemistry of TCNE, TCNQ and related polynitrile π acceptors|journal=Coordination Chemistry Reviews|volume=129|pages=157–193|doi=10.1016/0010-8545(94)85020-8|year=1994|issue=1–2 }}</ref>

===Charge transfer salts===
TCNQ achieved great attention because it forms ]s with high ]. These discoveries were influential in the development of ]. Illustrative is the product from treatment of TCNQ with the ] ] (TTF), TCNQ forms an ion pair, the TTF-TCNQ complex, in which TCNQ is the ]. This ] crystallizes in a one-dimensionally stacked ], consisting of segregated stacks of ] and ] of the donors and the acceptors, respectively. The complex crystal is an ] that exhibits metallic ].<ref>{{cite journal|author=Torrance, Jerry B. |title=The difference between metallic and insulating salts of tetracyanoquinodimethone (TCNQ): how to design an organic metal|journal=Accounts of Chemical Research|volume=12|issue=3|pages=79–86|doi=10.1021/ar50135a001|year=1979}}</ref>

==Related compounds==
*], another ] that functions as an ].
*], another ] that functions as an ].


==References== ==References==
{{Commons category}}
<references/>
{{reflist}}


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