7, 7, 8, 8-Tetracyanoquinodimethane TCNQ

Photoirradiation of 7,7,8,8-tetracyanoquinodimethane (TCNQ) in toluene afforded 1,6-addition product (pseudoexcitation band in Scheme 32) [145], The 1,6-addition thermally occurs with a stronger donor, p-methoxytoluene (transfer band in Scheme 32) [146]. 

A variety of other highly-strained electron-rich donors also form colored complexes (similar to homobenzvalene) with various electron acceptors, which readily undergo thermal cycloadditions (with concomitant bleaching of the color).209 For example, Tsuji et al.210 reported that dispiro[2.2.2.2]deca-4,9-diene (DDD), with an unusually low ionization potential of 7.5 eV,211 readily forms a colored charge-transfer complex with tetracyanoquinodimethane (TCNQ). The [DDD, TCNQ] charge-transfer complex undergoes a thermal cycloaddition to [3,3]paracyclophane in excellent yield, i.e.,... 

Cyanocarbon syntheses by the E. I. Dupont de Nemours Co. (1950-1964), which yielded several interesting electrical semiconductors based on the electron acceptor 7,7,8,8-tetracyanoquinodimethan (TCNQ). 

The electron acceptor 7,7,8,8-tetracyanoquinodimethane (TCNQ, 145) is capable of abstracting one electron from a donor molecule, yielding deeply colored solutions of a... 

Fe(abptrz)2(tcnq)2] is an iron(II) complex of the triazole 4-amino-3,5-bis(pyridin-2-yl)-1,2,4-triazole (abptrz) and the 7,7, 8,8 -tetracyanoquinodimethane (tcnq) radical anion whose structure, (132), Mossbauer and IR spectra, and magnetic behavior (thermally induced (280 K) spin crossover -S = 2 -S = 0) have been established. " ... 

The aim of the study was to create high-sensitive point-contact type gas sensors based on derivatives of 7,7,8,8-tetracyanoquinodimethane (TCNQ) and to test them in analysis of exhaled air for diagnosis and monitoring of human organism state. 

The infinite-dilution half-wave potential of 7,7,8,8-tetracyanoquinodimethane (TCNQ)... 

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). 

Much work has been undertaken to modify electrode surfaces with films which are themselves conducting. The most promising approaches involve organic charge transfer and radical ion polymers. Coordination chemistry has, to date, played little part in this work (a good recent review is available),67 but one example relating to ferrocene chemistry can be quoted. In this example a well known electron acceptor, 7,7, 8,8 -tetracyanoquinodimethane (TCNQ 27), is modified and incorporated into polymer (28) in which the iron(II) of the ferrocene unit is the electron donor. The electrical conductivity of such a film will depend on partial electron transfer between ion and TCNQ centres as well as on the stacking of the polymer chains. The chemistry of other materials, based on coordination compounds, which have enhanced electrical conductivity is covered in Chapter 61. 

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). 

BDTT is one of the most powerful donors of the TTF class. Alkylthio-substitution, such as in BEDT-TTF (ET), leads to a slight reduction in its electron-donor capability. Nevertheless, salts of this cation radical with tetracyanoquinodimethane (TCNQ) and its... 

Mediators such as 7,7,8,8-tetracyanoquinodimethane (TCNQ) [166], hexacyanoferrate(III) [168] and CoPC [169], which have been applied to a carbon paste or ink, are reduced by the reaction with thiocholine and then reoxidised at the carbon electrode (Fig. 23.6). A second type of mediator has involved the addition of Prussian blue (ferric hex-anocyanoferrate) into an AChE and choline oxidase (ChO) bienzyme biosensor. Prussian blue mediates the reduction of hydrogen peroxide produced by the conversion of choline to betaine by ChO [170]. 

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