- Halogenated benzene cation radicals
-
The halogenated benzenes C6HF5, 2,4,6-C 6H3F3, 2,3,5,6-C6H2F 4, C6F6, C6Cl6, C 6Br6, and C6I6 were converted into their corresponding cation radicals by using various strong oxidants. The cation-radical salts were isolated and characterized by electron paramagnetic resonance (EPR) spectroscopy and by single-crystal X-ray diffraction. The thermal stability of the cation radicals increased with decreasing hydrogen content. As expected, the cation radicals [C6HF5] + and 2,3,5,6-[C6H2F4]+ had structures with the same geometry as C6HF5 and 2,3,5,6-[C6H2F4]. In contrast, the cation radicals [C6F6]+, [C6Cl 6]+, and possibly also [C6Br6] + exhibited Jahn-Teller-distorted geometries in the crystalline state. In the case of C6F6+Sb2F 11-, two low-symmetry geometries were observed in the same crystal. Interestingly, the structures of the cation radicals 2,4,6-[C 6H3F3]+ and C6I 6+ did not exhibit Jahn-Teller distortions. DFT calculations showed that the explanation for the lack of distortion of these cations from the D3h or D6h symmetry of the neutral benzene precursor was different for 2,4,6-[C6H3F 3]+ than for [C6I6]+. Copyright
- Molski, Matthias J.,Mollenhauer, Doreen,Gohr, Sebastian,Paulus, Beate,Khanfar, Monther A.,Shorafa, Hashem,Strauss, Steven H.,Seppelt, Konrad
-
-
Read Online
- A direct and convenient synthesis of periodoarenes using molecular iodine
-
Molecular iodine exhaustively iodinates aromatic hydrocarbons in the presence of potassium peroxodisulfate, concentrated sulfuric acid, and trifluoroacetic acid to give the periodinated aromatic compounds. Benzene and other moderately activated and deactivated arenes are readily converted into the corresponding periodinated derivatives in good to high yields.
- Rahman, Md. Ataur,Shito, Fumiaki,Kitamura, Tsugio
-
experimental part
p. 27 - 29
(2010/04/26)
-
- Polyiodination on benzene at room temperature. A regioselective synthesis of derivatives
-
Reaction of IPy2BF4 with benzene and CF3SO3H in CH2Cl2 gives regioselectively polyiodinated compounds at room temperature, providing a definitely easy synthetic entry to those rarely accessible benzene derivatives.
- Barluenga,Gonzalez,Garcia-Martin,Campos
-
p. 3893 - 3896
(2007/10/02)
-
- Direct Polyiodination of Benzenesulfonic Acid
-
Direct aromatic polyiodination of benzenesulfonic acid (using I2 and H5IO6 in H2SO4 at room temperature) was performed to test the possible intermediacy of C6H5SO3H in the corresponding direct polyiodination of benzene to C6H2I4.The major product from C6H5SO3H was 3,4,5-triiodobenzenesulfonic acid (4).In contrast, no 4 was formed in the C6H6 reaction, showing that no significant sulfonation of C6H6 to C6H5SO3H occurred during benzene iodination.Compound 4 itself was shown to be inert under the reaction conditions.A pathway is proposed from C6H5SO3H to the other reaction products (C6I6, C6I5H, two C6I4H2 isomers, and 3,4,5-triiodophenol), which therefore avoids the intermediacy of 4.
- Mattern, Daniell Lewis,Chen, Xinhua
-
p. 5903 - 5907
(2007/10/02)
-
- Direct Aromatic Periodination
-
Periodic acid and iodine in concentrated sulfuric acid exhaustively iodinated unactivated aromatic substrates.Thus benzene, nitrobenzene, benzoic acid, chlorobenzene, phthalic anhydride, and toluene were all converted to their periodo derivatives.Benzonitrile was converted to pentaiodobenzamide.This direct method compared favorably with the only general periodination procedure available, a mercuration/iododemercuration sequence.Partially iodinated products were obtained under less vigorous conditions.Thus, triiodo derivatives were obtained from nitrobenzene, benzo-ic acid, and toluene; tetraiodo derivatives were obtained from benzene, chlorobenzene, and trifluorobenzene.
- Mattern, Daniell Lewis
-
p. 3051 - 3053
(2007/10/02)
-