A compound of formula (I) or a dimer thereof; where R
1
and R
2
are independently selected from optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, a functional group or a group of sub-formula (i) where m is 0 or 1; p is an integer of from 1 to 12; R
7
is a group of formula —C
q
X
2q+1
where q is an integer of from 1 to 12 and X is halogen such as fluoro, or
7
a group of sub-formula (ii) where k is an integer of from 1 to 10, R
8
, R
10
, and R
12
and each R
9
and R
11
are independently selected from alkyl, alkenyl or aryl, such as lower alkyl and in particular methyl; provided that at least one of R
1
or R
2
is a group of sub-formula (i); R
3
, R
4
, R
5
and R
6
are independently selected from hydrogen or halogen, and in particular fluorine, n is 0 or 1, and A is a ring structure as specified. Compounds of formula (I) may have liquid crystal properties and/or be useful in liquid crystal devices.
化合物的公式为(I)或其二聚体;其中R1和R2分别选择自可选取代的烷基,可选取代的烯基,可选取代的炔基,功能基团或亚式(I)的基团,其中m为0或1; p为1到12的整数; R7为公式-CqX2q+1的基团,其中q为1到12的整数,X为卤素,例如
氟,或亚式(ii)的基团,其中k为1到10的整数,R8,R10和R12以及每个R9和R11分别选择自烷基,烯基或芳基,例如低烷基,尤其是甲基; 但要求R1或R2中至少有一个是亚式(I)的基团; R3,R4,R5和R6分别选择自氢或卤素,尤其是
氟,n为0或1,A为指定的环结构。公式(I)的化合物可能具有液晶性质,并且/或在液晶器件中有用。