Tetracyanoquinodimethane synthesis

Other miscellaneous applications of malononitdle are the synthesis of 7,7,8,8-tetracyanoquinodimethane (46) which is a powerful electron acceptor in the formation of charge-transfer complexes which are of interest because of their conductivity of electricity (96), as well as of 2-chloroben2yhdene malononitnle [2698-41-1] (45) also known as CS-gas, which is a safe lachrymatory chemical used for self-defense devices (97). 

Another synthesis of olefins has been described in which the desulphurization of thiirans by triphenylphosphine is featured.72 There have been many reports of the synthesis of compounds of the type (63). These form charge-transfer complexes with acceptors such as tetracyanoquinodimethane which have metallic properties. The... 

The presence of a cyano group seems to be important[649]. The reaction has been successfully applied to halides of pyridine, quinoline, isoquinoline, and oxazoles[650]. An interesting application is the synthesis of tetracyanoquinodimethane (789) by the reaction of /7-diiodobenzene with malononitrile[651]. 

Acceptors. Most common acceptor molecules such as tetracyanoethylene or tetracyanoquinodimethane are commercially available. However, TCNQ can be synthesized in high yield by a two-step synthesis involving a condensation of malonitrile with 1,4-cydohexanedione followed by treatment with an oxidizing agent such as bromine or AJ-bromosuccinamide in pyridine solvent (23) (Fig. 6). 

The synthesis of the strong cyanocarbon acceptors tetracyanoethylene (TCNE, 8) in 1957 [7], and 7,7,8-8-tetracyanoquinodimethan (TCNQ, 9a) in 1960 [8] heralded intensive studies of organic ionic crystals, with unusual magnetic properties [9-11] and also unusually high conductivity in some of... 

Nucleophilic attack at nitrogen has also been identified in a study of the reactions of triarylphosphines with tetracyanoethylene in aqueous acetonitrile. In contrast, the related reactions with tetracyanoquinodimethane (TCNQ) involve one electron transfer from phosphorus to the TCNQ molecule. Full details of the reactions of tertiary and ditertiary phosphines with bromophenyldiazirines have now appeared. Interest in the Staudinger reaction of tertiary phosphines with azides has also been maintained. A spectroscopic study has shown that the sequence of addition of reactants alters the course of the Staudinger reaction of azides in the presence of acyl derivatives. The Staudinger reaction of a-azidophenylacetonitrile with triphenylphosphine unexpectedly results in the formation of the salt (135). Applications of the Staudinger reaction in synthesis... 

The partially oxidized tetracyanoplatinate materials and a number of anion radical salts based on tetracyanoquinodimethane satisfy these requirements. Additional experimental work is in order to apply these concepts to the synthesis of new materials. 

Arylation of active methylene compounds has been carried out using Cu salts as promoters under severe conditions [2], Recently it was discovered that the reaction can be carried out much more smoothly using Pd catalysts. The first Pd-catalyzed intermolecular arylation of cyanoacetate and malononitrile with aryl iodides was carried out by Takahashi using PPhs as a ligand, and was applied to a simple synthesis of tetracyanoquinodimethane (2) by the reaction of p-diiodobenzene with malononitrile [3], The intramolecular arylation of malonates and -diketones with aryl iodides proceeds smoothly. Presence of a cyano group seemed to be important [4,5], The arylation has been successfully extended to halides of heterocycles, such as pyridine, quinoline and isoquinoline. The reaction of bromoxazole 3 with sulfone 4 is an example [6]. 

The discovery that the charge-transfer salt derived from tetrathiafulvalene (54 R = H) and tetracyanoquinodimethane (55) has metal-like behaviour, and shows a remarkable electrical conductivity over a wide temperature range, has stimulated a large volume of work on the design and synthesis of organic metals . ... 

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