- Iron-catalysed fluoroaromatic coupling reactions under catalytic modulation with 1,2-bis(diphenylphosphino)benzene
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A catalytic amount of 1,2-bis(diphenylphosphino)benzene (DPPBz) achieves selective cleavage of sp3-carbon-halogen bond in the iron-catalysed cross-coupling between polyfluorinated arylzinc reagents and alkyl halides, which was unachievable with
- Hatakeyama, Takuji,Kondo, Yoshiyuki,Fujiwara, Yu-Ichi,Takaya, Hikaru,Ito, Shingo,Nakamura, Eiichi,Nakamura, Masaharu
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supporting information; experimental part
p. 1216 - 1218
(2009/07/10)
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- Trifluorinated liquid crystals for TFT displays
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3, 4, 5-tri-fluorobenzene derivatives with different core structures have been synthesized and their physical properties have been determined. Most of the compounds are nematic with broad existence regions. The materials have large dielectric anisotropy, low viscosity, low optical anisotropy and very good voltage holding ratio and high chemical stability and are valuable components for mixtures to be used in TFT displays. The good voltage holding ratio of the compounds is related to their high electrical resistivity. In order to reproduce the dependence of the resistivity on the dielectric constant, we derived a general formula. Its derivation is based on the interaction of the impurity ions with the induced and permanent dipoles of the liquid crystal molecules. We are able to show, that ion/ion interactions in highly purified liquid crystals may be neglected.
- Demus,Goto,Sawada,Nakagawa,Saito
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- Trifluorobenzene derivative and liquid crystal composition containing the same
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A trifluorobenzene derivative having a superior stability and a large positive dielectric anisotropy value and a liquid crystal composition containing the derivative are provided, which derivative is expressed by the formula STR1 wherein R is 1-10C alkyl and one --CH2 -- group or two not-adjacent --CH2 -- groups in the alkyl may be replaced by O and/or --CO-- and/or --COO-- and/or --CH=CH--, --A-- and --B-- are 1,4-cyclohexylene, 1,4-phenylene, pyrimidine-2,5-diyl or 1,3-dioxane-2,5-diyl, l and m each are 0, 1 or 2 and l+m≥1, and Z1 and Z2 each are --COO--, --OCO--, --CH2 CH2 --, --OCH2 --, --CH2 O--, --CH=CH-- or single bond and may be same or different.
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