7.7.8.8- Tetracyanoquinodi-methane radical

Allyl (27, 60, 119-125) and benzyl (26, 27, 60, 121, 125-133) radicals have been studied intensively. Other theoretical studies have concerned pentadienyl (60,124), triphenylmethyl-type radicals (27), odd polyenes and odd a,w-diphenylpolyenes (60), radicals of the benzyl and phenalenyl types (60), cyclohexadienyl and a-hydronaphthyl (134), radical ions of nonalternant hydrocarbons (11, 135), radical anions derived from nitroso- and nitrobenzene, benzonitrile, and four polycyanobenzenes (10), anilino and phenoxyl radicals (130), tetramethyl-p-phenylenediamine radical cation (56), tetracyanoquinodi-methane radical anion (62), perfluoro-2,l,3-benzoselenadiazole radical anion (136), 0-protonated neutral aromatic ketyl radicals (137), benzene cation (138), benzene anion (139-141), paracyclophane radical anion (141), sulfur-containing conjugated radicals (142), nitrogen-containing violenes (143), and p-semi-quinones (17, 144, 145). Some representative results are presented in Figure 12. 

More recently, crystalline cation-radical anion-radical salts of the donor tetrathiofulvalene with the acceptors tetracyanoquinodi-methane (Phillips et al., 1973 Ferraris et al., 1973 Butler et al., 1974) and tetracyanomuconitrile (WudI and Southwick, 1974) have... 

Section 15.7 contains tables of magnetic data obtained from anion radicals of compounds fliat don t comfortably fall into any of the previous sections. The subsection on fullerene anion radicals requires a special note as there are several papers of around the same period which vary shghtly in the preparation, solvent or physical parameters of the measurements. As the only data in many cases is the g factor it was decided to include the majority of these entries even though they relate to the same species. The data have been divided into the following subsections sulphides and sulphones, imines and imides, fullerenes, tetracyanoquinodi-methanes, phenylcarbonitriles, phosphaaUcenes and alkylcyclosilanes. Some of these subsections have been further subdivided. 

The stabilization of the radical cation in SDS micelles is consistent with the formation of the surface complex already mentioned in Sect. 2.1.1. There are a number of examples of the stabilization of radical ions in micelles of the opposite sign. The electrochemical reduction of nitrobenzene in homogeneous solutions is two-electronic, but in micellar CTAB solutions it is resolved into two separate reactions [135]. So the presence of cationic micelles inhibits the disproportionation of nitrobenzene radical anions. It may be caused by the reduced mobility of the radical ions in the surface layer of the micelles due to complex formation with the end groups of the micelles. It can account for the inhibition of the disproportionation because the latter needs a coUision of two radical ions. The salt formation of the radical cation of N-methylphenothiazine with the end groups of SDS micelles was proposed in the study of electrochemical oxidation of N-methylphenothiazine in micellar solution [136]. Tetracyanoquinodi-methane is solubilized in dodecylpyridinium-inverted micelles in the form of a radical anion with the oxidation of the iodide ion [137]. 

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