Tetracyanoethylene

Tetracyanoethylene
	tetracyanoethylene
Names
	IUPAC name Ethenetetracarbonitrile
	Other names TCNE
Identifiers
CAS Number	670-54-2 ;
3D model (JSmol)	Interactive image;
ChemSpider	12114 ;
ECHA InfoCard	100.010.527
PubChem CID	12635;
UNII	C592309ECU ;
CompTox Dashboard (EPA)	DTXSID7049425 ;
	InChI InChI=1S/C6N4/c7-1-5(2-8)6(3-9)4-10 Key: NLDYACGHTUPAQU-UHFFFAOYSA-N ; InChI=1/C6N4/c7-1-5(2-8)6(3-9)4-10 Key: NLDYACGHTUPAQU-UHFFFAOYAN;
	SMILES N#CC(C#N)=C(C#N)C#N;
Properties
Chemical formula	C6N4
Molar mass	128.094 g·mol−1
Density	1.35 g/cm3
Melting point	199 °C (390 °F; 472 K)
Boiling point	130 to 140 °C (266 to 284 °F; 403 to 413 K) 0.1 mmHg (sublimes)
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). verify (what is ?) Infobox references

Tetracyanoethylene (TCNE) is organic compound with the formula C₂(CN)₄. It is a colorless solid. It is an important member of the cyanocarbons.

Synthesis and reactions

TCNE is prepared by brominating malononitrile in the presence of potassium bromide to give the KBr-complex, and dehalogenating with copper.^[1]

Oxidation of TCNE with hydrogen peroxide gives the corresponding epoxide, which has unusual properties.^[2]

Redox chemistry

TCNE is often used as an electron acceptor. Cyano groups have low energy π* orbitals, and the presence of four such groups, with their π systems (conjugated) to the central C=C double bond, gives rise to an electrophilic alkene. TCNE is reduced by iodide to give the radical anion:

C₂(CN)₄ + I⁻ → [C₂(CN)₄]⁻ + 1⁄2 I₂

Because of its planarity and its ability to accept electrons, TCNE has been used to prepare numerous organic superconductors, usually by serving as a single electron oxidant of an organic electron donor. Such charge-transfer salts are sometimes called Bechgaard salts.

Safety

TCNE hydrolyzes in moist air to give hydrogen cyanide and should be handled accordingly.^[1]

References

^ ^a ^b ^c Carboni, R. A. (1963). "Tetracyanoethylene". Organic Syntheses; Collected Volumes, vol. 4, p. 877.
^ Linn, W. J. (1973). "Tetracyanoethylene Oxide". Organic Syntheses; Collected Volumes, vol. 5, p. 1007.

[Carboni-1] Carboni, R. A. (1963). "Tetracyanoethylene". Organic Syntheses; Collected Volumes, vol. 4, p. 877.

[2] Linn, W. J. (1973). "Tetracyanoethylene Oxide". Organic Syntheses; Collected Volumes, vol. 5, p. 1007.

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