Tetracyanoethylene

Chembox new
Name = Tetracyanoethylene
ImageFileL1 = TCNE.png ImageSizeL1 = 100px
ImageName =
ImageFileR1 = TCNE3D.png ImageSizeR1 = 150px
ImageNameR1 = tetracyanoethylene
IUPACName = tetracyanoethene
OtherNames = TCNE
Section1 = Chembox Identifiers
CASNo = 670-54-2
SMILES = N#CC(C#N)=C(C#N)C#N
Section2 = Chembox Properties
Formula = C₆N₄
MolarMass = 128.09 g/mol
Density = g/cm³
MeltingPt = 199 °C
SublimationConditions = 130-140 °C
(0.1 mm Hg)OrgSynth | author = Carboni, R. A. | title = Tetracyanoethylene | collvol = 4 | collvolpages = 877 | year = 1963 | prep = cv4p0877]

Tetracyanoethylene (TCNE) is a yellow colored organic compound consisting of ethylene with the four hydrogen atom replaced with cyano groups. It is an important member of the cyanocarbons.

ynthesis and reactions

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

Oxidation of TCNE with hydrogen peroxide gives the corresponding epoxide, which has unusual properties. [OrgSynth | author = Linn, W. J. | title = Tetracyanoethylene Oxide | collvol = 5 | collvolpages = 1007 | year =1973 | prep = cv5p1007]

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 linked (conjugated) to the central C=C double bond, gives rise to an excellent acceptor. Thus, treatment of TCNE with iodide salts gives the radical anion::C₂(CN)₄ + I^- → [C₂(CN)₄] ^- + 0.5 I₂Because 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 salt.

afety

TCNE hydrolyzes in moist air to give hydrogen cyanide and should be handled accordingly.

References