| abstract |
The invention is to provide liquid crystalline compoundsnhaving a negative and extremely large dielectric anisotropynvalue and a small optical anisotropy value at the same time; liquidncrystal compositions comprising the compound; and liquid crystalndisplay devices fabricated by using the liquid crystalncomposition; the liquid crystalline compounds have 2,3-dihalogenophenylenenmoiety and are expressed by formula (1)n nwherein Ra and Rb each independently represents a linear ornbranched alkyl having 1 to 10 carbon, any methylene in the alkylnmay be replaced by -O-, -S-, -CH=CH-, or -C≡C-, but -O- is notnsuccessive, and any hydrogen in the alkyl may be replaced bynhalogen; rings A 1 to A 4 each independently represents trans-1,4-cyclohexylene,ncyclohexene-1,4-diyl, pyridine-1,4-diyl,npyrimidine-2,5-diyl, or 1,4-phenylene, wherein at least onenhydrogen in these rings may be replaced by halogen, and anynnonadjacent methylene in cyclohexane ring may be replaced by -O-;nY 1 and Y 2 each independently represents F or Cl; Z 1 , Z 2 and Z 3 eachnindependently represents a single bond, -CH 2 CH 2 -, -(CH 2 ) 4 -, -COO-,n-OCO-, -CH 2 O-, -OCH 2 -, -CF 2 O-, or -OCF 2 -; and l, m and n eachnindependently is 0, 1 or 2, and the sum of l + m + n is 3 and less. |