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Benzene anion

Benzene anion radical Methanol Cyclohexadienyl radical Methoxide ion... [Pg.440]

The benzene anion formed as shown by nucleophilic attack on an aromatic ring is called a Meisenheimer complex. [Pg.129]

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. [Pg.359]

When ESR spectra were obtained for the benzene anion radical, [C6II6] and the methyl radical, CH3, the proton hyperfine coupling constants were found to be 3.75 and 23.0 G, respectively, i.e. they differ by about a factor of 6. Since the carbon atom of CH3 has a spin density corresponding to one unpaired electron and the benzene anion carries an electron spin density of 1/6, the two results suggest that the proton coupling to an electron in a n-orbital is proportional to the spin density on the adjacent carbon atom ... [Pg.27]

For example, in a radical with six equivalent carbon atoms (e.g., benzene anion radical), the probabilities are P0 = 0.936, Pi = 0.062, P2 = 0.0017, P3 = 0.00003, etc. In practice, we would probably see only the central line with intensity 0.936 and a pair of satellites with intensity 0.031, corresponding to splitting of the center line by a single 13C (the intensity is distributed between the two resonances). [Pg.38]

Neutral hexakis(methylsulfonyl)benzene (see Scheme 6.23) adopts a chair conformation. On the contrary, the tube conformer appears to be inherent in the corresponding anion-radical. The methylsulfonyl fragments at positions 1 and 4 of the bent benzene ring are nonequivalent. Moreover, one methylsulfonyl moiety is nonequivalent to all of the other five (Fabre et al. 2002). Scheme 6.23 depicts an intuitively constructed picture. Localization of spin-charge density within one methylsulfonyl group causes the attraction of the other from position 4. This makes the tube conformation the most stable in the case of hexakis(methylsulfonyl)benzene anion-radical. [Pg.335]

Fig. 8.13 The first-derivative ESR spectrum of the benzene anion radical C6H. The relative intensities are 1 6 15 20 15 6 1. Fig. 8.13 The first-derivative ESR spectrum of the benzene anion radical C6H. The relative intensities are 1 6 15 20 15 6 1.
A. Benzene Anion and its Derivatives Not only is the benzene anion the simplest aromatic system containing one antibonding tt-electron, hut it differs from most other such ions... [Pg.300]

Proton Coupling Constants for Benzene Anions and Some Derivatives (G) (Bedford et al., in press Bolton and Carrington, 1961a Bolton el al., 1962a)... [Pg.302]

This approach is not expected to apply when there is considerable 7T-bonding between the substituent and the ring. Thus the anion of nitrobenzene probably has a structure more analogous to that of the benzyl radical rather than to that of the benzene anion, and the results (Maki and Geske, 1960) are indeed closer to those expected for such a model than for a model in which the impaired electron is placed in the symmetric e2 level of benzene. [Pg.303]

Although attempts to prepare the benzene cation and its simple alkyl derivatives have so far been unsuccessful (Bolton and Carrington, 1961b Hulme, unpublished results) it is perhaps legitimate to consider the phenoxy radical, recently detected during the oxidation of phenol by Stone and Waters (1962), as a derivative of the benzene cation, by the same token that the anion of nitrobenzene is treated as a derivative of the benzene anion. Thus the phenoxy radical may be depicted in its zwitterionic form... [Pg.306]

An interesting aspect of this problem is that posed by the Jahn-Teller effect in the benzene anion. These ions, together with the cations and anions of coronene (Bolton and Carrington, 1961c de Boer and Weissman, 1958), have spectra consisting of unusually broad lines which are very hard to saturate. Theoretical studies (McConnell, 1961 McConnell and McLachlan, 1961) suggest that the broadening is a result of spin-orbit interaction but the relaxation is linked to the dynamic Jahn-Teller effect. [Pg.353]

Fluorinated benzene anions were obtained238-242 by X-irradiating adamantane matrices containing the aromatic precursor and also Me3NBH3 as electron donor. [Pg.321]

Heteroatoms also influence the charge carried by heteroaromatic radicals, just as they influence that of diamagnetic aromatic species. Thus, addition of an electron to the aromatic cations 15 and 16 yields radicals which are, respectively, neutral and cationic, albeit isoelectron ic with benzene anion-radicals. [Pg.214]

Proton hyperfine splitting pattern in the ESR spectrum of the benzene anion radical. [Pg.457]

The constant Q is of the order of 20 to -30 gauss for aromatic hydrocarbons, and the benzene anion value of ( = 6 X 3.75 = -22.5 gauss is conunonly used. This relation... [Pg.458]

Another interesting observation is that alkyl substitution causes a substantial decrease in the lifetime of benzene anions ( ). We believe that this is due to the presence of the = 1 and 1=2 partial waves in the charge density of the LUMO of the alkylbenzenes. The benzene anion symmetry) itself has a leading partial wave of = 3. [Pg.2]

Sandwich compounds have been reported from the reaction of bora-benzene anions with iron(II) chloride. [Pg.176]

As a consequence, it is not surprising that there appears to be only one isolated structure claimed. This is of the indium(I) and thallium(I) complexes with a single M—C bond from a o--bonded benzene anion that carries two bulky tri-substituted benzene substituents in ortho positions these partially block approach of other potential donors to the metal cation (Figure 4.3). An X-ray crystal structure has been determined, defining the shape. It is a rare observation, as other complexes (such as Mn(I) and Fe(I)) of the same ligand bind another ligand at the open side of the molecule, as expected. In any case, this coordination number is trivial in the sense that it can have only one shape - a linear M—L arrangement. [Pg.86]


See other pages where Benzene anion is mentioned: [Pg.131]    [Pg.134]    [Pg.86]    [Pg.221]    [Pg.222]    [Pg.88]    [Pg.283]    [Pg.286]    [Pg.12]    [Pg.918]    [Pg.89]    [Pg.170]    [Pg.283]    [Pg.301]    [Pg.301]    [Pg.309]    [Pg.318]    [Pg.321]    [Pg.131]    [Pg.134]    [Pg.319]    [Pg.178]    [Pg.458]    [Pg.131]    [Pg.134]    [Pg.298]    [Pg.178]    [Pg.413]   
See also in sourсe #XX -- [ Pg.140 ]




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