670-54-2

Basic information

• Product Name: Tetracyanoethylene
• Synonyms: 1,1,2,2-Tetracyanoethene;1,1,2,2-Tetracyanoethylene;delta(sup2,2’)-bimalononitrile;delta2,2'-Bimalononitrile;Ethene, tetracyano-;Ethylene, tetracyano-;Tetracyanoethene;Tetracyanoαthylen(ausderSchmelze)
• CAS NO: 670-54-2
• Molecular Formula: C₆N₄
• Molecular Weight: 128.09
• EINECS: 211-578-0
• Product Categories: Acceptors (Charge Transfer Complexes);Charge Transfer Complexes for Organic Metals;Functional Materials;TCNQ Derivatives;organic compound
• Mol File: 670-54-2.mol

Chemical Properties

• Melting Point: 197-199 °C(lit.)
• Boiling Point: 223 °C
• Flash Point: 223°C
• Appearance: White to beige-brown/Crystalline Powder, Crystals or Chunks
• Density: 1,348 g/cm3
• Vapor Pressure: 0.117mmHg at 25°C
• Refractive Index: 1.5600
• Storage Temp.: 2-8°C
• Water Solubility: hydrolyzes
• Sensitive: Moisture Sensitive
• Merck: 14,9195
• BRN: 1679885
• CAS DataBase Reference: Tetracyanoethylene(CAS DataBase Reference)
• NIST Chemistry Reference: Tetracyanoethylene(670-54-2)
• EPA Substance Registry System: Tetracyanoethylene(670-54-2)

Safety Data

• Hazard Codes: T+
• Statements: 20/21-28-23/24
• Safety Statements: 28-36/37-45-28A-22-1
• RIDADR: UN 2811 6.1/PG 1
• WGK Germany: 3
• RTECS: KM7300000
• TSCA: Yes
• HazardClass: 6.1
• PackingGroup: II
• Hazardous Substances Data: 670-54-2(Hazardous Substances Data)

Usage

Chemical Description

Tetracyanoethylene is a highly reactive organic compound used in the synthesis of various organic compounds.

Chemical Description

Tetracyanoethylene is a highly reactive organic compound used in organic synthesis and as a building block for other chemicals.

Uses

1. Used in Organic Synthesis:
Tetracyanoethylene is used as a reactant for various organic synthesis applications, including:
a. Postfunctional addition to polyphenylacetylene derivatives to alter their oxygen permeability.
b. Regioselective [2+2] cycloaddition reaction for the production of BODIPY dyes and TCBD derivatives.
c. Thermal addition reaction with alkynes.
d. One-pot reactions with nucleophilic reagents to form aromatic cyanovinyl compounds.
e. Synthesis of cobalt tetracyanoethylene films.
2. Used in the Production of Organic Superconductors:
Tetracyanoethylene is used as an electron acceptor in the preparation of organic superconductors, often serving as a single electron oxidant of an organic electron donor. These charge-transfer salts are sometimes referred to as Bechgaard salts.
3. Used in Biotransformation:
Tetracyanoethylene is utilized in the biotransformation process by Botrytis cinerea, a type of fungus.
4. Used in Modified Diels-Alder Reactions:
TCNE is employed in modified Diels-Alder reactions, which are important in organic chemistry for the synthesis of various complex molecules.
5. Used as an Aromatizing Agent:
Tetracyanoethylene is also used as an aromatizing agent, contributing to the development of new fragrances and scents in the chemical industry.

Synthesis Reference(s)

Organic Syntheses, Coll. Vol. 4, p. 877, 1963The Journal of Organic Chemistry, 45, p. 5113, 1980 DOI: 10.1021/jo01313a019

Hazard

Hydrolyzes in moist air to hydrogen cyanide.

Purification Methods

Crystallise it from chlorobenzene, dichloroethane, or dichloromethane [Hall et al. J Org Chem 52 5528 1987]. Storeitat0oina desiccator over NaOH pellets. (It slowly evolves HCN on exposure to moist air CARE.) It can also be sublimed at 120o under vacuum. Also purify it by repeated sublimation at 120-130o/0.5mm. [Frey et al. J Am Chem Soc 107 748 1985, Traylor & Miksztal J Am Chem Soc 109 2778 1987, Fatiadi Synthesis 249 1986, Synthesis 749 1967, Beilstein 2 IV 1245.]

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

Upstream product

• 1885-23-0 dibromomalononitrile 
• 109-77-3 malononitrile 
• 14778-29-1 1,1,2,2,-tetracyanoethane 
• 5362-78-7 dimethylsulfonium dicyanomethylide 
• 1625-84-9 9,10-dihydro-9,10-ethano-anthracene-11,11,12,12-tetracarbonitrile 
• 66333-78-6 C₂₂H₁₄N₄ 
• 492-97-7 cation radical of 2,2'-bithiophene 
• 94581-95-0 BrαT radical cation 
• 110230-97-2 CNαT radical cation 
• 2605-01-8 tetracyanoethylene*hexamethylbenzene 
• 128504-00-7 dipyrido<1,2-b:1',2'-e><1,2,4,5>tetrazine*ethylenetetracarbonitrile 
• 20484-50-8 TCNE-1-Phenylpyrrol-Komplex 
• 20484-51-9 TCNE-1-p-Tolylpyrrol-Komplex 
• 20484-61-1 TCNE-1-(p-Chlorphenyl)-pyrrol-Komplex 

Downstream Products

• 94074-32-5 (4-chloro-anilino)-ethenetricarbonitrile 
• 22442-56-4 2,6-dimethyl-4-tricyanovinylaniline 
• 108954-75-2 2-Cyano-3-(2,6-dimethyl-phenylamino)-but-2-enedinitrile 
• 1214-09-1 3-Tricyanovinylindol 
• 97460-75-8 (1,2,3,4-tetrahydro-quinolin-6-yl)-ethenetricarbonitrile 
• 109504-23-6 (4-morpholin-4-yl-phenyl)-ethenetricarbonitrile 
• 102888-98-2 4,4-bis-(4-dimethylamino-phenyl)-buta-1,3-diene-1,1,2-tricarbonitrile 
• 25751-81-9 2-(4-hydroxy-3,5-dimethyl-phenyl)-ethene-1,1,2-tricarbonitrile 
• 101281-30-5 4-(4-methyl-pent-3-enyl)-cyclohex-4-ene-1,1,2,2-tetracarbonitrile 
• 1625-84-9 9,10-dihydro-9,10-ethano-anthracene-11,11,12,12-tetracarbonitrile 
• 109563-39-5 (4-dimethylamino-3-methyl-phenyl)-ethenetricarbonitrile 
• 62166-71-6 (N-methyl-p-toluidino)-ethenetricarbonitrile 
• 117440-01-4 7-methylene-5,6-diphenyl-spiro[4.4]hept-5-ene-1,1,2,2-tetracarbonitrile 
• 53663-17-5 tetramethylammonium pentacyanopropenide 

Relevant articles and documents

Effect of external pressure and solvent on the equilibrium constant of the Diels-Alder reaction of 9-chloroanthracene with tetracyanoethylene

The effect of external pressure and solvent on the equilibrium constant of the Diels-Alder reaction of tetracyanoethylene with 9-chloroanthracene at 25°C was studied. The molar reaction volume is strongly solvent-dependent, cm3/mol: -11.3±1.0 in ?-xylene, -14.9±1.0 in toluene, -20.6±1.5 in 1,2-dichloroethane, -22.6±1.5 in ethyl acetate, and -24.2±1.5 in acetonitrile.

Photoinduced Electron Transfer between Acenaphthylene and Tetracyanoethylene: Effect of Irradiation Mode on Reactivity of the Charge-Transfer Complex and the Resulted Radical Ion Pair in Solution and Crystalline State

The mechanism of photodimerization of acenaphthylene (ACN) and of reactions with tetracyanoethylene (TCNE) by electron transfer (ET) has been investigated in solution and solid state to elucidate the role of the radical cation of ACN (ACN+?) in formation of the cisoid-dimer (cisoid-1) and the transoid-dimer (transoid-1) of ACN and addition products to TCNE. Selective excitation of the 1:1 charge-transfer (CT) complex between ACN and TCNE with light of >500 nm did not result in any reaction in acetonitrile (AN) or 1,2-dichloroethane (DCE). On the other hand, direct irradiation of ACN with light of >400 nm in solution in the presence of TCNE gave cisoid-1 and transoid-1 as the major products together with a [2 + 2]-adduct (2) and two isomeric [2 + 2 + 2]-adducts (3 and 4) of ACN and TCNE as minor products. Distinction of photochemical reactivity between selective CT excitation and direct excitation of ACN can be attributed to faster backward electron transfer (BET) from the contact radical ion pair (CIP) on CT excitation than from the solvent-separated radical ion pair (SSIP) on direct excitation of ACN due to very low energy for BET, as low as 1.34 V. Effect of [TCNE] on quantum yield for the dimerization of ACN and on the cisoid / transoid ratio of the resulted 1 rationalizes the mechanism involving the singlet and triplet SSIP; the former tends to undergo BET, but the latter undergoes dissociation to ACN+?, followed by formation of dimeric radical cation of ACN, ACN2+?, finally leading to 1. A possible mechanism for formation of 3 and 4 is discussed on the basis of concentration dependence of ACN. Contrary to photochemical inertness of the CT complex in solutions, CT excitation of the 1:1 crystal of ACN and TCNE (ACN·TCNE) gave 2 as the sole product. The selective formation of 2 indicates that fixation of the two alkenic C=C double bonds in ACN·TCNE separated by 3-4 A in both the excited CT state and the resulted CIP retards the deactivation and BET but enables them to undergo cycloaddition.

Synthesis of tetracyanoethylene by oxidative dimerization of malononitrile

A simple laboratory procedure has been proposed for the synthesis of tetracyanoethylene in up to 54% yield by oxidative dimerization of malononitrile in the presence of selenium(IV) oxide.

Structure of Spurs in γ-Irradiated Alcohol Matrices Determined by Electron Spin-Echo Method

Paramagnetic relaxation rates of radiation-generated tetracyanoethylene anion radicals (TCNE(1-)) and chemically prepared TCNE(1-) in the glassy matrices of ethanol, 1-propanol and 1-butanol, and radiation-generated CH3CHOH radicals in neat ethanol matrices have been measured by an electron spin-echo method for elucidating the detailed structure of spurs generated in the alcohol matrices γ-irradiated at 77 K.The local concentrations of hydroxyalkyl radicals generated in pair with TCNE(1-) or CH3CHOH radicals in isolated spurs were determined by analyzing the rates of excitation transfer from the magnetically excited TCNE(1-) or CH3CHOH radicals to the hydroxylakyl radicals.Comparison of the local concentrations of CH3CHOH radicals in ethanol matrices with and without solute tetracyanoethylene reveaked that the average number of ion pairs in a spur is close to unity.The distribution function of the distance r between TCNE(1-) and the paired hydroxyalyl radical, φ(r), was derived from relaxation kinetics of TCNE(1-), and was found to be expressed by φ(r)=3 exp(-r6/r06)(2?3/2r03).The average distances between TCNE(1-) and the paired hydroxyalkyl radicals were determined from the local concentrations of the hydroxyalkyl radicals, and were about 5 nm for all the alcohol matrices.

Electronic, infrared, mass spectrometry and thermal studies on the reaction of 2-amino-6-methylpyridine with π-acceptors

The spectrophotometric characteristics of the solid charge-transfer molecular complexes (CT) formed in the reaction of the electron donor 2-amino-6-methylpyridine (2A6MPy) with the π-acceptors tetracyanoethylene (TCNE), 2,3-dichloro-5,6-dicyano-1,4-benzoq

Reactivity Variation of Tetracyanoethylene and 4-Phenyl-1,2,4-Triazoline-3,5-Dione in Cycloaddition Reactions in Solutions

The reasons for the very high reactivity and variability of reactivity of two dienophiles, tetracyanoethylene (1) and 4-phenyl-1,2,4-triazoline-3,5-dione (2), in the Diels–Alder reactions were considered. The data on the rate of reactions with anthracene (3), benzanthracene (4) and dibenzanthracene (5) in 14 solvents over a range of temperatures and high pressures, data on the change in the enthalpy of solvation of reagents, transition state, and adducts in the forward and backward reactions, and the enthalpies of these reactions in solution were obtained. Strong π-acceptor dienophile 1 has sharply reduced reactivity in reactions in π-donor aromatic solvents. It was observed that the π-acceptor properties of dienophile 1 disappear upon passage to the transition state and adduct. Large solvent effects on the reaction rate can be predicted for all types of reactions involving tetracyanoethylene. Very high reactivity of dienophiles 1 and, especially, 2 can be useful to catch such carcinogenic impurities such as 3–5 and neutralize them by transformation into less dangerous adducts.

Spectroscopic and thermal investigations on the charge transfer interaction between risperidone as a schizophrenia drug with some traditional π-acceptors: Part 2

The focus of present investigation was to assess the utility of non-expensive techniques in the evaluation of risperidone (Ris) in solid and solution states with different traditional π-acceptors and subsequent incorporation of the analytical determination into pharmaceutical formulation for a faster release of risperidone. Charge-transfer complexes (CTC) of risperidone with picric acid (PA), 2,3-dichloro-5,6-dicyano-p-benzoquinon (DDQ), tetracyanoquinodimethane (TCNQ), tetracyano ethylene (TCNE), tetrabromo-p-quinon (BL) and tetrachloro-p-quinon (CL) have been studied spectrophotometrically in absolute methanol at room temperature. The stoichiometries of the complexes were found to be 1:1 ratio by the photometric molar ratio between risperidone and the π-acceptors. The equilibrium constants, molar extinction coefficient (εCT) and spectroscopic-physical parameters (standard free energy (ΔGo), oscillator strength (f), transition dipole moment (μ), resonance energy (RN) and ionization potential (ID)) of the complexes were determined upon the modified Benesi-Hildebrand equation. Risperidone in pure form was applied in this study. The results indicate that the formation constants for the complexes depend on the nature of electron acceptors and donor, and also the spectral studies of the complexes were determined by (infrared, Raman, and 1H NMR) spectra and X-ray powder diffraction (XRD). The most stable mono-protonated form of Ris is characterized by the formation of +NH (pyrimidine ring) intramolecular hydrogen bonded. In the high-wavenumber spectral region ～3400 cm-1, the bands of the +NH stretching vibrations and of the pyrimidine nitrogen atom could be potentially useful to discriminate the investigated forms of Ris. The infrared spectra of both Ris complexes are confirming the participation of +NH pyrimidine ring in the donor-acceptor interaction.

Why can the activation volume of the cycloadduct decomposition in isopolar retro-diels-alder reactions be negative?

Rate constants of the Diels-Alder cycloaddition reaction of anthracene with tetracyanoethylene, enthalpy of solution of reactants and adduct, enthalpy of the reaction in solution, enthalpy and entropy of activation of the forward and retro-Diels-Alder reactions were determined in 14 solvents. Temperature and pressure effects on the rate of the decomposition of the adduct formed from 9-chloroanthracene and tetracyanoethylene were studied. Since the electrostriction effect can be excluded from the consideration of the isopolar Diels-Alder reaction, negative values of the activation volume in the retro-Diels-Alder reactions can be caused by the different possibilities of penetration of the solvent molecules to large steric branched structures of the transition states and adducts.

One-pot new synthetic method for 3-amino-2-quinoxalinecarbonitrile

A new method for the preparation of 3-amino-2-quinoxalinecarbonitrile (1) was studied. A successful condensation reaction between bromomalononitrile and o-phenylenediamine in the presence of Lewis acid catalyst (AlCl3) was achieved to produce compound 1.

Continuum of outer- and inner-sphere mechanisms for organic electron transfer. Steric modulation of the precursor complex in paramagnetic (ion-radical) self-exchanges

Transient 1:1 precursor complexes for intermolecular self-exchange between various organic electron donors (D) and their paramagnetic cation radicals (D+.), as well as between different electron acceptors (A) paired with their anion radicals (A .), are spectrally (UV-NIR) observed and structurally (X-ray) identified as the cofacial (π-stacked) associates [D, D+.] and [A-.· A], respectively. Mulliken-Hush (two-state) analysis of their diagnostic intervalence bands affords the electronic coupling elements (HOA), which together with the Marcus reorganization energies (λ) from the NIR spectral data are confirmed by molecular-orbital computations. The HDA values are found to be a sensitive function of the bulky substituents surrounding the redox centers. As a result, the steric modulation of the donor/acceptor separation (rDA) leads to distinctive electron-transfer rates between sterically hindered donors/acceptors and their more open (unsubstituted) parents. The latter is discussed in the context of a continuous series of outer- and inner-sphere mechanisms for organic electron-transfer processes in a manner originally formulated by Taube and co-workers for inorganic (coordination) donor/acceptor dyads-with conciliatory attention paid to traditional organic versus inorganic concepts.