| abstract |
A novel liquid crystal material having a carbon chain containing a conjugated diene as a terminal substituent of the molecule and exhibiting superior characteristics is provided, which is a diene derivative expressed by the formula (I) ##STR1## wherein R and R' each independently represent 1-5C alkyl; A and B each independently represent 1,4-cyclohexylene or 1,4-phenylene; n is 0 or 1; m is an integer of 0 to 2; X and X' each independently represent H atom or F atom when A is 1,4-phenylene or represent H atom when A is 1,4-cyclohexylene; Y is alkyl, halogen or CN, alkoxy, methyl group substituted by 1-3 halogen atoms or trihaloalkoxy when A is 1,4-phenylene, or represent alkyl, alkoxy, methyl group substituted by 1-3 halogen atoms or trihaloalkoxy when A is 1,4-cyclohexylene; and R and R' are not simultaneously alkyl chain of 4 or more carbon atoms. n The compound of the present invention has a generally usable viscosity and a high NI point and a high elastic constant ratio; hence the liquid crystal composition, particularly the liquid crystal composition for STN, containing the compound of the present invention exhibits improved characteristics as compared with the conventional ones. |