| 摘要 |
The invention is to provide liquid crystalline compounds having a negative and extremely large dielectric anisotropy value and a small optical anisotropy value at the same time; liquid crystal compositions comprising the compound; and liquid crystal display devices fabricated by using the liquid crystal composition; the liquid crystalline compounds have 2,3-dihalogenophenylene moiety and are expressed by formula (1)wherein Ra and Rb each independently represents a linear or branched alkyl having 1 to 10 carbon, any methylene in the alkyl may be replaced by -O-, -S-, -CH=CH-, or -C=C-, but -O- is not successive, and any hydrogen in the alkyl may be replaced by halogen; rings A1 to A4 each independently represents trans-1,4-cyclohexylene, cyclohexene-1,4-diyl, pyridine-1,4-diyl, pyrimidine-2,5-diyl, or 1,4-phenylene, wherein at least one hydrogen in these rings may be replaced by halogen, and any nonadjacent methylene in cyclohexane ring may be replaced by -O-; Y1 and Y2 each independently represents F or Cl; Z1, Z2 and Z3 each independently represents a single bond, -CH2CH2-, -(CH2)4-, -COO-, -OCO-, -CH2O-, -OCH2-, -CF2O-, or -OCF2-; and l, m and n each independently is 0, 1 or 2, and the sum of l+m+n is 3 and less.
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