Dichloro-anthracene

Chlorobenzene or syw-tetrachlorethane may be used instead of carbon tetrachloride as solvent, in which case the reaction is complete as soon as the mixture has reached reflux. The product is liable to be contaminated by a small amount of 9,10-dichloro-anthracene. 

The encapsulations of organic molecules, like 9,10-dichloro-anthracene, jS-carotene, and coronene was found to be effective to increase the reversible storage capacity. Especially for the SWNT with coronene, the reversible capacity is 736 mAh/g, which is about 2.5 times greater than that of original empty tube. This is due to the steric hindrance of the organic molecules in the tube. The electrol3 e molecules and solvated Li ions cannot enter the tube. 

The Diels-Alder reaction of 9,10-dichloro-anthracenes with 1,1-dichloro-ethene gives a mixture of (360) and (361), and an interesting high-temperature reaction of hydrogen sulphide with the 9-halogeno-derivatives of polynuclear aromatic hydrocarbons led to the corresponding sulphide R2S, e.g. (362). 

Examples include luminescence from anthracene crystals subjected to alternating electric current (159), luminescence from electron recombination with the carbazole free radical produced by photolysis of potassium carba2ole in a fro2en glass matrix (160), reactions of free radicals with solvated electrons (155), and reduction of mtheiiium(III)tris(bipyridyl) with the hydrated electron (161). Other examples include the oxidation of aromatic radical anions with such oxidants as chlorine or ben2oyl peroxide (162,163), and the reduction of 9,10-dichloro-9,10-diphenyl-9,10-dihydroanthracene with the 9,10-diphenylanthracene radical anion (162,164). Many other examples of electron-transfer chemiluminescence have been reported (156,165). 

Similarly, 1-vinylcyclohexane can be trapped with dimethyl acetylenedicarboxylate in refluxing xylene to afford 195 in 78% yield (equation 126)119. Benzo[ ]anthracene can be obtained by the reaction of 196 and 1,2-dihydronaphthalene (equation 127) and oxidation of 197 with 2,3-dichloro-5,6-dicyano-l,4-benzoquinone120. 

Chloroanthracene has been prepared by the action of chlorine,2 tert-butyl hypochlorite, l,3-dichloro-5,5-dimethylhy-dantoin, or phosphorus pentachloride 5 on anthracene. 

The study of the cycloaddition behavior of l,l-dichloro-2-neopentylsilene, C Si =CHCH2Bu (2) [3], reveals the high polarity of the Si=C bond and a strong electrophilicity. The [4+2] cycloaddition reactions with anthracene (3), cyclopentadiene (4) and fulvenes (5) proceed as expected surprising, however, the Diels-Alder reactions with dienes are of lower activity, like naphthalene (6) and furans (7). 

Fig. 14 Transient absorption spectrum of anthracene cation radical (ANT+ ) obtained upon 30-ps laser excitation of the [ANT, OsOJ charge-transfer complex in dichloro-methane. The inset shows the authentic spectrum of ANT+ obtained by an independent (electrochemical) method. Reproduced with permission from Ref. 96b.

This aldehyde synthesis is applicable to compounds of the aromatic series having a labile hydrogen atom (phenyl ethers,1 naphthols,2 dialkylanilines,3-4 naphthostyril,2 anthrones 2) and to certain hydrocarbons of requisite reactivity (anthracene,5-6 7 1,2-benzanthracene,6 3,4-benzpyrene,3 7 pyrene,8 styrene,9 and a, a-diarylethylenes 9). With polynuclear hydrocarbons the best results are secured by the use of a solvent such as o-dichloro-benzene. 9-Anthraldehyde has also been prepared by the action of hydrogen cyanide and aluminum chloride on anthracene in chlorobenzene.10... 

In the syntheses of these compounds, very high stereoselectivity was noted. In every case, the entering dienophile approaches the least hindered side of the substituted anthracene. Thus tire ap isomer is the almost exclusive product of the reaction. As an extension of this finding, atropisomers of 9-(l,I-dimethyl-2-phenylethyl)-2,3-dichlorotriptycene (101) were prepared separately the ap form by treating 9-( 1,1 -dimethyl-2-phenylethyl)anthracene with 4,5-dichlorobenzyne, and the sc form by treating 2,3-dichloro-9-(l,l-dimethyl-2-phenylethyl)-... 

Lund and coworkers [131] pioneered the use of aromatic anion radicals as mediators in a study of the catalytic reduction of bromobenzene by the electrogenerated anion radical of chrysene. Other early investigations involved the catalytic reduction of 1-bromo- and 1-chlorobutane by the anion radicals of trans-stilhene and anthracene [132], of 1-chlorohexane and 6-chloro-l-hexene by the naphthalene anion radical [133], and of 1-chlorooctane by the phenanthrene anion radical [134]. Simonet and coworkers [135] pointed out that a catalytically formed alkyl radical can react with an aromatic anion radical to form an alkylated aromatic hydrocarbon. Additional, comparatively recent work has centered on electron transfer between aromatic anion radicals and l,2-dichloro-l,2-diphenylethane [136], on reductive coupling of tert-butyl bromide with azobenzene, quinoxaline, and anthracene [137], and on the reactions of aromatic anion radicals with substituted benzyl chlorides [138], with... 

In the case of anthracene, the stable monoclinic phase transforms under stress to a triclinic phase in which molecules are favourably oriented for dimerization to occur. Although the triclinic phase has not been isolated as a pure phase, its structure has been established using low-temperature electron microscopy and atom-atom potential calculations (Jones Thomas, 1979). In l,8-dichloro-9-methyl anthracene, isolated dislocations with (201) [010] translation bring the molecules to the required geometry (Fig. 8.17) to facilitate photodimerization. 1, 5-dichloroanthracene is an interesting case. Instead of the expected 100% head-to-head dimers, photoreaction yields 80%... 

The longest wave absorption band of anthracene is short axis polarized. The substitution in 9,10 positions leads to a bathochromic shift in this band. The intrinsic lifetimes are proportional to Jandean be obtained from the area under the respective absorption curves. The molar extinction coefficients are 9, 10-dichloro-A > 9-chloro-A > A. The lifetime decreases with increase of absorbance and at the same time the fluorescence efficiency f is observed to increase. The values of f f°r various anthracenes in CC14 and the quantum efficiencies of their reactions with the solvent, both in absence of oxygen, are presented in Table 11.5. 

Various PCBs (dichloro to hexachloro) 0.3-0.4 Benzo[a]anthracene (NaCl) 0.35... 

The charge-transfer crystal of 1,4-dithiin and anthracene was grown in dichloro-methane solution (50 mM) by slow evaporation of solvent at low temperature (-4 °C). After one week, a brown single crystal was isolated. The solid-state reaction of the anthracene-1,4-dithiin CT crystals was carried out at four temperatures (viz. 50, 60, 70 and 80 °C), and the conversion was monitered by XH NMR spectroscopy. 

The crystal structures of a series of anthracene derivatives (9-nitro- and 9,10-dinitro-anthracene, 9,10-dichloro- and 9,10-dibromo-anthracene, and 9-anthraldehyde) have been investigated by Trotter (1958a, 1959a, b). In 9-anthraldehyde (65) significant out-of-plane... 

Distannyl derivatives have also been used as starting materials for the synthesis of fluorinated ort/io-phenylene diboranes. The reaction of l,2-bis(trimethylstannyl)tetra-fluorobenzene (18)22 with BC13 affords 9,10-dichloro-9,10-dihydro-9,10-di-boraoctafluoroanthracene (15) (Scheme 9).23,24 This compound can be further de-rivatized by treatment with bis(pentafluorophenyl)dimethyltin which affords the fully fluorinated 9,10-bis(pentafluorophenyl)-9,10-dihydro-9,10-diboraoctafluoro-anthracene (19). This conversion can also be effected by the reaction of 15 with bis(pentafluorophenyl)zinc.21... 

Similarly, halogenation of anthracene involves addition at the 9,10-positions, giving 9,10-dichloro-9,10-dihydroanthracene which on heating loses HCl to form 9-chloroanthracene. 

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