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The condensation reactions between (4-amino-2,6-dichlorophenyl)bis(2, 4,6-trichlorophenyl)methyl radical and acetylacetone or 1, 4-bis(5-methyl-2-thienyl)-1,4-butanedione yield [2,6-dichloro-4-(2, 5-dimethyl-1-pyrrolyl)phenyl]bis(2,4,6-trichlorophenyl)methyl radical (3(*)()) and [2,6-dichloro-4-[2, 5-bis(5-methyl-2-thienyl)-1-pyrrolyl]phenyl]bis(2,4, 6-trichlorophenyl)methyl radical (4(*)()), respectively. EPR studies of both radicals 3(*)() and 4(*)() in CH(2)Cl(2) solution suggest a weak electron delocalization with coupling constant values of 1.25 and 1.30 G, respectively, with the six aromatic hydrogens. Their electrochemical behavior was analyzed by cyclic voltammetry. Both radicals show reversible reduction processes at E degrees = -0.69 V and -0.61 V versus SSCE, respectively, and anodic peak potentials at E(p)(a) = 1.10 and 0.72 V, respectively, versus SSCE at a scan rate (nu) of 200 mV s(-)(1), being reversible for radical 4(*)(). X-ray analysis of radical 3(*)() shows a high value (65 degrees ) of the dihedral angle between the 2,5-dimethylpyrrolidyl moiety and the phenyl ring. Smooth oxidation of radical 4(*)() in CH(2)Cl(2) containing trifluoroacetic acid gives an ionic diradical species with a weak electron interaction (|D/hc| = 0.0047 cm(-)(1)). A Curie plot of the Deltam(s)() = +/-2 signal intensity versus the inverse of the absolute temperature in the range between 4 and 70 K suggests a triplet or a nearly degenerate singlet-triplet ground state.

Photochlorinations of nonachloro-3-(chloromethyl)-1,4-dihydronaphthalene (1) and nonachloro-7-(chloromethyl)-1,4-dihydronaphthalene (2) give nonachloro-3-(dichloromethyl)-1,4-dihydronaphthalene (3) and nonachloro-7-(dichloromethyl)-1,4-dihydronaphthalene (4), respectively. Dechlorination of both 3 and 4 by means of SnCl2.2H2O affords heptachloro-7-(dichloromethyl)naphthalene (5). Photobromination of heptachloro-7-methylnaphthalene (6) with Br2 results in 2-(bromomethyl)heptachloronaphthalene (8) or heptachloro-7-(dibromomethyl)naphthalene (7), depending on the reaction time. Intermediate 8 can be prepared in high yield by bromination of 6 with NBS in the presence of AIBN. Theoretical calculations in 7 indicate the existence of two energetically favoured conformers and that one of them seems to be slightly more stable than the other one. Accordingly, the 1H NMR spectra of 5, 7, and 2-(bromochloromethyl)heptachloronaphthalene (9) are temperature dependent, displaying two singlets that collapse in a sharp singlet about 100°C. Although the two conformers of 5, 7, and 9 can be detected in solution, only the most stable of each pair, at least in the case of 7, is present in solid form (X-ray analysis). A dynamic 1H NMR study shows that the barriers to rotation of CHCl2, CHBrCl, and CHBr2 groups in 5, 9, and 7 are as high as 16.8, 18.2, and 19.3 kcal mol−1, respectively. The X-ray structure of 7 is commented, and spectral data of the synthesized compounds are reported.

Tris(2,4,6-trichlorophenyl)carbenium hexachloro-antimonate (2), (2,6-dichloro-4-hydroxyphenyl)bis(2,4,6-trichlorophenyl)methyl radical (4) and its methyl ether derivative 5 have been synthesized and isolated as crystalline solids. In contrast to 5, radical 4 is not very stable in air, and the disappearance of 4 by aerial oxidation has been monitored by UV-vis spectroscopy. The EPR spectra of 4 and 5 are reported and commented upon.

Dichlorobis(pentachlorophenyl)germane (3) has been prepared by reaction of GeCl4 with either pentachlorophenyllithium or pentachlorophenylmagnesium chloride. After neutral hydrolysis of 3, bis(pentachlorophenyl)germanediol (8) has been isolated and characterized as a stable solid. Thermal dehydration of 8 has been studied by thermogravimetry (TG) and differential scanning calorimetry (DSC), the product being {(C6Cl5)2GeOn}. Reaction of 3 with methanol leads to dimethoxybis(pentachlorophenyl)germane (4). Reduction of 3 with LiAlH4 gives bis(pentachlorophenyl)germane (5) which, on treatment with Br2 and I2, gives dibromo- (6) and diiodobis(pentachlorophenyl)germane (7), respectively. The molecular structure of the diiodogermane 7 has been fully established by X-ray crystallography.

Photochlorinations of nonachloro-3-(chloromethyl)-1,4-dihydronaphthalene (1) and nonachloro-7-(chloromethyl)-1,4-dihydronaphthalene (2) give nonachloro-3-(dichloromethyl)-1,4-dihydronaphthalene (3) and nonachloro-7-(dichloromethyl)-1,4-dihydronaphthalene (4), respectively. Dechlorination of both 3 and 4 by means of SnCl2.2H2O affords heptachloro-7-(dichloromethyl)naphthalene (5). Photobromination of heptachloro-7-methylnaphthalene (6) with Br2 results in 2-(bromomethyl)heptachloronaphthalene (8) or heptachloro-7-(dibromomethyl)naphthalene (7), depending on the reaction time. Intermediate 8 can be prepared in high yield by bromination of 6 with NBS in the presence of AIBN. Theoretical calculations in 7 indicate the existence of two energetically favoured conformers and that one of them seems to be slightly more stable than the other one. Accordingly, the 1H NMR spectra of 5, 7, and 2-(bromochloromethyl)heptachloronaphthalene (9) are temperature dependent, displaying two singlets that collapse in a sharp singlet about 100°C. Although the two conformers of 5, 7, and 9 can be detected in solution, only the most stable of each pair, at least in the case of 7, is present in solid form (X-ray analysis). A dynamic 1H NMR study shows that the barriers to rotation of CHCl2, CHBrCl, and CHBr2 groups in 5, 9, and 7 are as high as 16.8, 18.2, and 19.3 kcal mol−1, respectively. The X-ray structure of 7 is commented, and spectral data of the synthesized compounds are reported.

The chlorination of 2-methylnaphthalene (1) and 1-methylnaphthalene (12) by means of Silberrad's reagent (initial components: SO 2 Cl 2 , S 2 Cl 2 , and AlCl 3 ) has been performed.We describe our results concerning the synthesis of the two heptachloro(chloromethyl)naphthalenes and the Friedel-Crafts alkylation of pentachlorobenzene

CCl 3 F in the presence of AlCl 3 is not only a very suitable reagent for the trifluoromethylation of polychlorobenzenes, but also for converting CCl 3 group into CF 3 group, at least in the cases of perchlorotoluene and 2,4,5-trichloro-1-(trichloromethyl)-benzene

Several polycloro(trifluoromethyl)benzenes have been prepared by treatment of the corresponding polychlorobenzenes with CCl3F and AlCl3. The resulting trifluoromethyl derivatives, by reaction with the same inorganic halide in CS2, give their trichloromethyl analogues.

The sulfonations of pentachlorobenzene (1) with 25% oleum at 40°C or 140°C, or with 65% oleum at 40°C give always excellent yields of pentachlorobenzenesulfonic anhydride (2). However, pentachlorobenzenesulfonic acid (3) is obtained when the working up of the reaction mixture is not mild enough to avoid the hydrolysis of the anhydride 2. Acid 3 is also synthesized starting from pentachlorophenol (4) via O-pentachlorophenyl dimethylthiocarbamate (6), its isomerization to S-pentachlorophenyl dimethylthiocarbamate (7) and final oxidation to 3. Pentachlorobenzenesulfonyl chloride (8) and anhydride (2) are also obtained from acid 3. Anhydride 2 reacts at 200°C with phenol 4 or pentachloroaniline (10) giving pentachlorophenyl pentachlorobenzenesulfonate (9), or a mixture of pentachlorobenzenesulfonyl pentachloroanilide (11) and pentachloroanilinium pentachlorobenzenesulfonate (12), respectively. Sulfonamide 11 can be obtained in two polymorphic forms and an ethyl ether solvate, for which interesting sp...