Tetracyanoquinodimethane complex salts

The electrical resistance of complex salts of the 2,4,6-triphenylthia-zinium cation and tetracyanoquinodimethane (TCNQ) has been measured. For one thiazinium cation and 2 mol of TCNQ, the specific resistances were found to be in the range of 5-15 fl/cm (82MI2). 

Charge-transfer complexes of dicyclopenteno 1,4,5,8-tetratellurafulvalene with a variety of donors such as tetracyanoquinodimethane were prepared7. By electrochemical oxidation cation radical salts with chloride, bromide, iodide, hexafluorophosphate, or hexaflu-oroarsenate as anions were obtained8. 

A1 1 charge-transfer complex was obtained when bis[9-telluraxanthenyl] and tetracyano-quinodimethane were combined in dimethylformamide or when bis[9-telluraxanthenyl] tetraiodide was reacted with the lithium salt of the anion radical of tetracyanoquinodimethane. ... 

Tetracyanoquinodimethane (TCNQ) and many of its derivatives are easily reduced to anions of the type TCNQ-, which form salts with various cations. With many cations, e.g., tetrathiafulvalene cations (TTF+), and N-methyl phenazinium cations (NMP+), the TCNQ- anions form electronically conducting salts (- molecular metals, -> charge-transfer complexes) that can be used as electrodes, especially because of their electrocatalytic properties (- biosensors, -> electrocatalysis, -> molecular metals) [i,ii]. TCNQ undergoes insertion electrochemical reactions (-> insertion electrochemistry) leading to TCNQ salts [iii, iv]. Polymers... 

Tetrathiafulvalene electrodes — Tetrathiafulvalene (TTF) and many of its derivatives are easily oxidized to form cations of the type TTF+. With various anions, most prominent is the tetracyanoquinodimethane anion (TCNQ-), these cations form - charge-transfer complexes, i.e., salts with metal-like conductivities (- molecular metals). These salts are used in electrochemistry as electrodes or to modify the surface of electrodes, for the purpose of achieving desirable electrocatalytic properties (- electrocatalysis). Tetrathiafulvalene-substituted polystyrenes have also been synthesized and used as modified electrodes [ii]. 

In the above radical-cation salts, the crystal contains partially oxidized donors, while the electroneutrality is achieved by the presence of closed shell anions. The structural requirements necessary for electrical conductivity in solid salts can also be met upon mixing of donors and acceptors in the resulting charge-transfer (CT) complexes both the donor and acceptor exist in a partially oxidized and reduced state, respectively. Famous examples are the conducting CT complexes formed upon mixing of perylene (112) [323. 324] and iodine or of tetrathiafulvalene (TTF, 119) as donor and 7,7,8,8-tetracyanoquinodimethane (TCNQ, 120) as acceptor [325-327] the crucial structural finding for the... 

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. ... 

Bisbenzene chromium reacts with good 77-acceptor Lewis acids to form complexes (CgHg)2Cr L" (L = tetracyanoethylene, trinitrobenzene, -quinone, chloranil) in which electron transfer from the (CgHg)2Cr to the Lewis acid has taken place. The complexes are best described as bisbenzene chromium cation salts of radical anions (765). The crystal structure of one such compound [(MeCgHg)2Cr] (TCNQ) (TCNQ = 7,7,8,8-tetracyanoquinodimethane) has been determined and consists of Stacks of TCNQ anions and bisbenzene chromium cations with interplanar spacings of 3.42 A (577). 

The molecules of GO are denatured as a consequence of their adsorption on graphite electrodes from their more concentrated solutions. This denaturation results in a release of flavin adenine dinucleotide (FAD), which is directly adsorbed at the electrode. If the concentration of GO in the bulk of solution is low ( < 20 M) a significant fraction of molecules is adsorbed only weakly and remains in the native state so that their catalytic activity remains preserved [225]. If, under these conditions, glucose is present in the bulk of solution, it is possible to detect electron exchange between GO and the graphite electrode [225]. Similar results can be obtained at so-called organic salt electrodes (these electrodes are composed of the complex of tetrathiaful-valene and tetracyanoquinodimethane (TTF-TCNQ) [226]. 

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