| 摘要 |
The present invention relates to a compound having a chroman ring, which has good thermal and optical stability, adequate optical anisotropy, adequate dielectric anisotropy and superior compatibility with other liquid crystal compounds, a liquid crystal composition comprising the compound, and a liquid crystal device comprising the composition. A compound represented by formula (1) below is provided:
where R a is hydrogen or C 1 -C 20 alkyl; R b is halogen, -CN, alkyl, alkenyl or alkoxy; each of A 1 , A 2 , A 3 and A 4 is independently 1,4-cyclohexylene, 1,4-cyclohexenylene or 1,4-phenylene, in which any -CH 2 - may be replaced by -O- or -S-, any -CH= may be replaced by -N=, and any hydrogen may be replaced by halogen, methyl or -CF 3 ; each of Z 1 , Z 2 , Z 3 and Z 4 is independently a single bond or C 1 -C 4 alkylene; each of h, k, m and n is independently 0, 1 or 2, the sum of h, k, m and n being 1, 2 or 3; and Q is one of the group represented by formulas (q1), (q2) and (q3) below:
where X 1 is hydrogen or halogen; and each of Y 1 , Y 2 , Y 3 , Y 4 and Y 5 is independently hydrogen, halogen or methyl. |
