Tetracyanoquinodimethane, preparation

Tetracyanoquinodimethane [1518-16-7] (5), 2,2 -(2,5-cyclohexadiene-l,4-diyhdene)bispropanedinitrile (TCNQ), is prepared by condensation of 1,4-cyclohexanedione with malononittile to give l,4-bis(dicyanomethylene)cyclohexane [1518-15-6] which is oxidized with bromine (31). 

The Menschutkin reaction has been used to prepare poly(viologens) (115) directly (Scheme 31). These polymers were found to be quite useful as polyelectrolyte redox-polymers and for the preparation of conductive polymers when complexed with the 7,7, 8,8 -tetracyanoquinodimethane (TCNQ) radical anion (71MI11100). 

Although arylation or alkenylation of active methylene compounds can be carried out using a Cu catalyst, the reaction is sluggish. However, the arylation of malononitrile (390) or cyanoacetate proceeds smoothly in the presence of a base and Pd catalysts [189], Tetracyanoquinodimethane (392) is prepared by the coupling of / -diiodoben-zene with malononitrile (390) to give 391, followed by oxidation [190], Presence of the cyano group seems to be essential for intermolecular reactions. However, the intramolecular arylation of malonates, / -keto esters and /i-diketones proceeds smoothly [191]. The bromoxazole 393 reacts with phenylsulphonylacetonitrile (394)... 

Alcohol Electrodes were prepared by layering 20 iL of a saturated solution of N-methyl phenazinium-tetracyanoquinodimethane onto a base graphite electrode. After drying, these electrodes were dipped in N-cyclohexyl-n (2-morpholinoethyl) -carbodimide methylpotoluene sulphonate for 90 minutes. They were then washed in carbonate buffer pH 9.8 and immersed in a solution of alcohol oxidase and peroxidase, and stabilized at various pH values. Electrodes were vacuum dried and stored under vacuum. 

Chemists of du Pont described the preparation of a series of new compounds with electron-accepting properties such 7,7,8,8-tetracyanoquinodimethane (TCNQ)72)... 

Metal-vapour-deposition methods have begun to provide new low-valent complexes of uncommon stoichiometry. The preparation of gram quantities of paramagnetic (ji = 2.02 BM) [Co(bipy)2] has been reported and its reactions with Br2, tetracyanoethylene and tetracyanoquinodimethane studied.283 Electrochemically it behaves identically to [Co(bipy)3]2+ (equation 47).283... 

An unusual anion exchange takes place in the reaction between 2,6-diphenylthiopyrylium (18) iodide and tetracyanoquinodimethane (TCNQ) in acetonitrile. The iodide ion undergoes oxidation to iodine, leaving as counter-ion of 18 the radical anion of TCNQ (77TH1). Salts of this type have been also prepared by metathesis (69JCP377). 

Nespurek (1984) and Nespurek et al. (1985) measured photogeneration efficiencies of vapor-deposited a-H c. Samples prepared with a surface layer of an acceptor compound, pyromellitic acid dianhydride or tetracyanoquinodimethane, were also studied. In the absence of an acceptor, the efficiencies were in the range of 0.01 to 0.02 at fields of KP V/cm. Nespurek and coworkers... 

The preparation and properties of the charge transfer salt between azonia derivative (2 and 246) and tetracyanoquinodimethane (TCNQ) were reported (88MI2). Wang and Jones reported that acridizinium salt underwent single crystal — single crystal photodimerization (87T1273). 

Charge-transfer complexes of dicyclopenteno 1,4,5,8-tetratellurafulvalene with a variety of donors such as tetracyanoquinodimethane were prepared. By electrochemical oxidation cation radical salts with chloride, bromide, iodide, hexafluorophosphate, or hexaflu-oroarsenate as anions were obtained . 

TTT is a powerful electron donor which forms radical-cation salts with many strong electron acceptors such as 2,5-cyclohexadiene-l,4-diylidene dimalononitrile (commonly named tetracyanoquinodimethane or TCNQ), o-chloranil, o-bromanil, o-iodanil, and tetracyanoethylene. These salts are prepared by mixing the components in an appropriate solvent and recovering the product as precipitate. With TCNQ the complex is a 1 1 association however it has the stoicheiometry (TTT) 3 A where n = 1 when Ais o-chloranil, o-bromanil, or o-iodanil and where n = 2 when A is tetracyanoethylene. ... 

After the discovery of the interesting electrical properties of tetrathia-fulvalene (TTF)-tetracyanoquinodimethane (TCNQ) complexes, many TTF derivatives have been prepared by reaction of 1,3-dithiolium salts with tertiary amines. This reaction has been interpreted as proceding by deprotonation of a 1,3-dithiolium cation to the corresponding carbene which in turn reacts as a nucleophile on the C-2 of another 1,3-dithiolium cation. This topic having been recently reviewed, we refer in Table 309,310 Qjjjy jQ papers subsequent to this review. ... 

Complexes of poly(7V-vinylcarbazole) and tetracyanoquinodimethane (TCNQ) have been prepared by treating PVK with TCNQ in dioxane solution followed by rapid evaporation of the solvent. A second method used a mixture of chloroform and methanol to prepare the complexes. In the latter case, the products precipitated as sticky materials which were separated and then dried. The electrical conductivities of complexes prepared with different ratios of reagents and by the two different methods were then evaluated [73]. 

A cell of this design was employed in studies of microcrystal solids attached to a platinum flag electrode [608]. The measured ESR spectrum of electrochem-ically reduced 7,7, 8,8 -tetracyanoquinodimethane was in perfect agreement with the respective spectrum of the chemically prepared compound and the simulated spectrum. 

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