Tetracyanoquinodimethane
| Tetracyanoquinodimethane (TCNQ) | |
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Other names
(2,5-Cyclohexadiene-1,4-diylidene) |
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| Identifiers | |
| CAS number | 1518-16-7  |
| PubChem | 73697 |
| ChemSpider | 66342 |
| ChEBI | CHEBI:52445 |
| Jmol-3D images | Image 1 |
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| Properties | |
| Molecular formula | C12H4N4 |
| Molar mass | 204.19 g/mol |
| Appearance | green-coloured crystals |
| Melting point |
293.5–296 °C |
| Boiling point |
sublimes |
| Hazards | |
| EU classification | not listed |
 (verify) (what is:  / ?)Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) |
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| Infobox references | |
Tetracyanoquinodimethane (TCNQ) is the organic compound with the formula (NC)2CC6H4C(CN)2. This relative of para-quinone is an electron-acceptor that is used to prepare charge transfer salts, which are of interest in the area of molecular electronics.
[edit] Preparation and use
TCNQ is prepared by the condensation of 1,4-cyclohexanedione with malononitrile, followed by dehydrogenation of the resulting diene with bromine:[1]
- C6H8O2 + 2 CH2(CN)2 → C6H8(C(CN)2)2 + 2 H2O
- C6H8(C(CN)2)2 + 2 Br2 → C6H4(C(CN)2)2 + 4 HBr
Like TCNE, TCNQ is easily reduced electrochemically to give a blue-coloured radical anion. Upon treatment with the electron donor tetrathiafulvene (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.
[edit] References
- ^ "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
