Compound having alkyl on benzene ring, liquid crystal composition having the compound, and liquid crystal display device having the liquid crystal composition

1. A compound represented by the following formula (1):

wherein Ra and Rb are independently alkyl having from 1 to 20 carbons, wherein arbitrary —CH 2 — in the alkyl may be replaced by —O—, —S—, —CO— or —SiH 2 —, arbitrary —(CH 2 ) 2 — may be replaced by —CH═CH— or —C═C—, and wherein arbitrary hydrogen may be replaced by halogen;

wherein ring A 1 is independently 1,4-cyclohexylene, 1,4-phenylene, pyridine-2,5-diyl, pyridazine-3,6-diyl, decahydronaphthalene-2,6-diyi, 1,2,3,4-tetrahydronaphthalene-2,6-diyl or naphthalene-2,6-diyl, wherein arbitrary —CH 2 — in each of A 1 may be replaced by —O—, —S—, —CO— or —SiH 2 —, and wherein arbitrary —(CH 2 ) 2 — in each of A 1 may be replaced by —CH═CH—, and wherein arbitrary hydrogen in each of A 1 may be replaced by halogen, —CF 3 , —CHF 2 , —CH 2 F, —OCF 3 , —OCHF 2 or —OCH 2 F;

wherein Z 1 is independently a single bond or alkylene having from 1 to 4 carbons, wherein arbitrary —CH 2 — in the alkylene may be replaced by —O—, —S—, —CO— or —SiH 2 —, wherein arbitrary —(CH 2 ) 2 — in the alkylene may be replaced by —CH═CH— or and wherein arbitrary hydrogen may be replaced by halogen;

wherein W is alkylene having from 2 to 4 carbons, wherein arbitrary —CH 2 — in the alkylene may be replaced by —O—, —S—, —CO— or —SiH 2 —, wherein arbitrary —(CH 2 ) 2 — in the alkylene may be replaced by —CH═CH— or —C≡C—, and wherein arbitrary hydrogen may be replaced by halogen;

wherein Y 1 is independently hydrogen, halogen, —CN, —CF 3 , —CHF 2 , —CH 2 F, —CF 3 , —OCHF 2 or —OCH 2 F, but wherein at least one of Y 1 is chlorine, —CF 3 , —CHF 2 , —CH 2 F, —OCF 3 , —OCHF 2 or —OCH 2 F;

wherein Rc is alkyl having from 1 to 4 carbons; and

wherein m is independently 0, 1 or 2; but wherein the sum of plural numbers of m is 0, 1 or 2.

2. The compound according to claim 1 , wherein in the formula (1), Ra and Rb are independently alkyl having from 1 to 20 carbons, alkoxy having from 1 to 19 carbons, alkoxyalkyl having from 2 to 19 carbons, alkenyl having from 2 to 20 carbons, polyfluoroalkyl having from 1 to 20 carbons or polyfluoroalkoxy having from 1 to 19 carbons;

wherein ring A 1 is independently 1,4-cyclohexylene, 1,3-dioxane-2,5-diyl, 1,4-phenylene, 2-fluoro-1,4-phenylene, 2,3-difluoro-1,4-phenylene, 2,5-difluoro-1,4-phenylene, 2,6-difluoro-1,4-phenylene, pyridine-2,5-diyl, 6-fluoropyridine-2,5-diyl or pyridazine-3,6-diyl;

wherein Z 1 is independently a single bond, —(CH 2 ) 2 —, —COO—, —OCO—,—CH 2 O—, —OCH 2 —, —CF 2 O—, —OCF 2 —, —CH═CH—, —CF═CF—, —C≡C—, —CH 2 CO—, —COCH 2 —, —CH 2 SiH 2 —, —SiH 2 CH 2 —, —(CH 2 ) 2 COO—, —OCO(CH 2 ) 2 —, —(CH 2 ) 2 CF 2 O—, —OCF 2 (CH 2 ) 2 —, —(CH 2 ) 3 —, —O(CH 2 ) 3 — or —(CH 2 ) 4 —; W is —COO—, —OCO—, —CH 2 —, —OCH 2 —, —CH═CH—, —CF═CF—, —C≡C—, —CF 2 O—, —OCF 2 —, —(CH 2 ) 2 COO— . OCO(CH 2 ) 2 —, —(CH 2 ) 3 —, —O(CH 2 ) 3 —, —(CH 2 ) 2 CF 2 —, —OCF 2 (CH 2 ) 2 — or —(CH 4 —;

wherein Y 1 is independently hydrogen, fluorine, chlorine, —CF 3 , —CHF 2 , —CH 2 F, —OCF 3 , —OCHF 2 or —OCH 2 F, but wherein at least one of Y 1 is chlorine, —CF 3 , —CHF 2 , —CH 2 F, —OCF 3 , —OCHF 2 or —OCH 2 F; and

wherein Rc is alkyl having from 2 to 4 carbons.

3. The compound according to claim 1 , wherein in the formula (1), Ra and Rb are independently alkyl having from 1 to 20 carbons, alkoxy having from 1 to 19 carbons, alkoxyalkyl having from 2 to 19 carbons, alkenyl having from 2 to 20 carbons, polyfluoroalkyl having from 1 to 20 carbons or polyfluoroalkoxy having from 1 to 19 carbons;

wherein ring A 1 is independently 1,4-cyclohexylene, 1,3-dioxane-2,5-diyl, 1,4-phenylene, 2-fluoro-1,4-phenylene, 2,3-difluoro-1,4-phenylene, 2,5-difluoro-1,4-phenylene, 2,6-difluoro-1,4-phenylene, pyridine-2,5-diyl, 6-fluoropyridine-2,5-diyl or pyridazine-3,6—diyl;

wherein Z 1 is independently a single bond, —(CH 2 ) 2 —, —COO—, —OCO—, —CH 2 O—, —OCH 2 —, —CF 2 O—, —OCF 2 —, —CH═CH—, —CF═CF—, —C≡—, CH 2 CO—, —COCH 2 —,—CH 2 SiH 2 —, —SiH 2 CH 2 —, —(CH 2 ) 2 COO—, —OCO—, (CH 2 ) 2 —, —(CH 2 ) 2 CF 2 O—, —OCF 2 (CH 2 ) 2 —, —(CH 2 ) 3 O—, —O(CH 2 ) 3 — or —(CH 2 ) 4 —; W is —(CH 2 —;

wherein Y 1 is independently hydrogen, fluorine, chlorine, —CF 3 , —CHF 2 , —CH 2 F, —OCF 3 , —OCHF 2 or —OCH 2 F, but wherein at least one of Y 1 is chlorine, —CF 3 , —CHF 2 , —CH 2 F, —OCF 3 , —OCHF 2 or —OCH 2 F; and

wherein Rc is alkyl having from 2 to 4 carbons.

4. The compound according to claim 1 , wherein in the formula (1), Ra and Rb are independently alkyl having from 1 to 8 carbons, alkoxy having from 1 to 7 carbons, alkoxyalkyl having from 2 to 7 carbons or alkenyl having from 2 to 8 carbons;

wherein ring A 1 is independently 1,4-cyclohexylene, 1,4-phenylene, 2-fluoro-1,4-phenylene or 2,3-difluoro-1,4-phenylene;

wherein Z 1 is independently a single bond or —(CH 2 ) 2 —;

wherein W is —(CH 2 ) 4 —, —CH 2 O—, —OCH 2 —, —CH═CH— or —C≡C—C—;

wherein Y 1 is independently hydrogen,, fluorine, —CH 2 F or —CF 3 , but wherein at least one of Y 1 is —CH 2 F or —CF 3 ; and

wherein Rc is —CH 3 .

5. The compound according to claim 1 , wherein in the formula (1), Ra and Rb is independently alkyl having from 1 to 8 carbons, alkoxy having from 1 to 7 carbons, alkoxyalkyl having from 2 to 7 carbons or alkenyl having from 2 to 8 carbons;

wherein ring A 1 is independently 1,4-cyclohexylene, 1,4-phenylene, 2-fluoro-1,4-phenylene or 2,3-difluoro-1,4-phenylene;

wherein Z 1 is independently a single bond or —(CH 2 ) 2 —; W is —(CH 2 ) 2 —;

wherein Y 1 is independently hydrogen, fluorine, —CF 2 H or —CF 3 , but wherein at least one of Y 1 is —CF 2 H or —CF 3 ; and

wherein Rc is —CH 3 .

6. A compound represented by any one of the following formulae (1-1) to (1-6):

wherein Ra and Rb are independently alkyl having from 1 to 10 carbons, wherein arbitrary —CH 2 — in the alky may be replaced by —O—, wherein arbitrary —(CH 2 ) 2 — in the alky may be replaced by —CH═CH— or —C≡C—, and wherein arbitrary hydrogen may be replaced by halogen;

wherein ring A 1 is independently 1,4-cyclohexylene, 1,4-phenylene, decahydronaphthalene-2,6-diyl, 1,2,3,4-tetrahydronaphthalene-2,6-diyl or naphthalene-2,6-diyl, wherein arbitrary —CH 2 — in each of A 1 may be replaced by —O—, and wherein arbitrary —(CH 2 ) 2 — in each of A 1 may be replaced by —CH═CH—, and wherein arbitrary hydrogen in each of A 1 may be replaced by halogen, —CF 3 , —CHF 2 or —CH 2 F;

wherein Z 1 is independently a single bond or alkylene having from 1 to 4 carbons, wherein arbitrary —CH 2 — in the alkylene may be replaced by —O— or —CO—, wherein arbitrary —(OH 2 ) 2 — in the alkylene may be replaced by —CH═CH—or and wherein arbitrary hydrogen may be replaced by halogen;

wherein W is —(CH 2 ) 2 —, —COO—, —OCO—, —CH 2 —, —OCH 2 —, —CH═CH—, —CF═CF—, —C≡C—, —CF 2 O—, —OCF 2 —, —(CH 2 ) 2 COO—, —OCO(CH 2 ) 2 —, —(CH 2 ) 3 O—, —O(CH 2 ) 3 —, —(CH 2 ) 2 CF 2 O—, —OCF 2 (CH 2 ) 2 — or —(CH 2 ) 4 —;

wherein Y 1 is independently hydrogen, halogen, —CF 3 , —CHF 2 or —CH 2 F, but wherein at least one of Y 1 is chlorine, —CF 3 , —CHF 2 or —CH 2 F; and

wherein Rc is alkyl having from 1 to 4 carbons, wherein arbitrary —CH 2 — in the alkyl may be replaced by —O—, and wherein arbitrary —(CH 2 ) 2 — in the alkyl may be replaced by —CH═CH— or —C≡C—.

7. The compound according to claim 6 , wherein in the formulae (1-1) to (1-6), Ra and Rb are independently alkyl having from 1 to 10 carbons, alkoxy having from 1 to 9 carbons, alkoxyalkyl having from 2 to 9 carbons, alkenyl having from 2 to 10 carbons, polyfluoroalkyl having from 1 to 10 carbons or polyfluoroalkoxy having from 2 to 10 carbons;

wherein ring A 1 is independently 1,4-cyclohexylene, 1,3-dioxane-2,5-diyl, 1,4-phenylene, 2-fluoro-1,4-phenylene, 2,3-difluoro-1,4-phenylene, 2,5-difluoro-1,4-phenylene or 2,6-difluoro-1,4-phenylene;

wherein Z 1 is independently a single bond, —(CH 2 ) 2 —, —COO—, —OCO—, —CH 2 O—, —OCH 2 —, —CF 2 O—, —OCF 2 —, —CH═CH—, —CF═CF—, —C≡C—, —(C 2 ) 2 COO—, —OCO(CH 2 ) 2 —, —(CH 2 ) 2 CF 2 O—, —OCF 2 (CH 2 ) 2 —, —(CH 2 ) 3 O—, —O(CH 2 ) 3 — or —(CH 2 ) 4 —;

wherein W is —COO—, —OCO—, —CH 2 O—, —OCH 2 —, —CH═CH—, —CF═CF—, —C≡C—, —CF 2 O—, —OCF 2 —, —(CH 2 ) 2 C 2 COO—, —OCO(CH 2 ) 2 —, —(CH 2 ) 3 O—, —O(CH 2 ) 3 —, —(CH 2 ) 2 CF 2 O—, —OCF 2 (CH 2 ) 2 — or —(CH 2 ) 4 —;

wherein Y 1 is independently hydrogen, fluorine, chlorine, —CF 3 , —CHF 2 or —CH 2 F, but wherein at least one of Y 1 is chlorine, —CF 3 , —CHF 2 or —CH 2 F; and

wherein Rc is alkyl having from 1 to 4 carbons, alkoxy having from 2 to 4 carbons, alkoxyalkyl having from 2 to 4 carbons or alkenyl having from 2 to 4 carbons.

8. The compound according to claim 6 , wherein in the formulae (1-1) to (1-6), Ra and Rb are independently alkyl having from 1 to 10 carbons, alkoxy having from 1 to 9 carbons, alkoxyalkyl having from 2 to 9 carbons, alkenyl having from 2 to 10 carbons, polyfluoroalkyl having from 1 to 10 carbons or polyfluoroalkoxy having from 2 to 10 carbons;

wherein ring A 1 is independently 1,4-cyclohexylene, 1,3-dioxane-2,5-diyl, 1,4-phenylene, 2-fluoro-1,4-phenylene, 2, 3— difluoro-1,4-phenylene, 2,5-difluoro-1,4-phenylene or 2,6-difluoro-1,4-phenylene;

wherein Z 1 is independently a single bond, —(CH 2 ) 2 —, —COO—, —OCO—, —CH 2 O—, —OCH 2 —, —CF 2 O—, —OCF 2 —, —CH═CH—, —CF═CF—, —C≡C—, (CH 2 ) 2 COO—, —OCO(CH 2 ) 2 —, —(CH 2 ) 2 CF 2 O—, —OCF 2 (CH 2 ) 2 —, —(CH 2 ) 3 O—, —O(CH 2 ) 3 — or —(CH 2 ) 4 —; W is —(CH 2 ) 2 —;

wherein Y 1 is independently hydrogen, fluorine, chlorine, —CF 3 , —CHF 2 or —CH 2 F, but wherein at least one of Y 1 is chlorine, —CF 3 , —CHF 2 or —CH 2 F; and

and wherein Rc is alkyl having from 1 to 4 carbons, alkoxy having from 2 to 4 carbons, alkoxyalkyl having from 2 to 4 carbons or alkenyl having from 2 to 4 carbons.

9. The compound according to claim 7 , wherein in the formulae (1-1) to (1-6), Ra and Rb are independently alkyl having from 1 to 10 carbons, alkoxy having from 1 to 9 carbons, alkoxyalkyl having from 2 to 9 carbons, alkenyl having from 2 to 10 carbons, —CH 2 F or —OCH 2 F;

wherein ring A 1 is independently 1,4-cyclohexylene, 1,4-phenylene, 2-fluoro-1,4-phenylene, 2,3-difluoro-1,4-phenylene, 2,5-difluoro-1,4-phenylene or 2,6-difluoro-1,4-phenylene;

wherein Z 1 is independently a single bond, —(CH 2 ) 2 —, —COO—, —OCO—, —CH 2 O—, —OCH 2 —, —CF 2 O—, —OCF 2 —, —CH═CH— or —CC—; W is —COO—, —OCO—, —CH 2 O—, —OCH 2 —, —CH═CH—, —CF═CF—, —C≡C—, —(CH 2 ) 2 COO —, —OCO(CH 2 ) 2 —, —(CH 2 ) 3 O—, —O(CH 2 ) 3 — or —(CH 2 ) 4 —;

wherein Y 1 is independently fluorine, chlorine, —CF 3 or —CHF 2 , but wherein at least one of Y 1 is chlorine, —CF 3 or —CHF 2 ; and

wherein Rc is alkyl having from 1 to 4 carbons.

10. The compound according to claim 7 , wherein in the formulae (1-1) to (1-6), Ra and Rb are independently alkyl having from 1 to 10 carbons, alkoxy having from 1 to 9 carbons, alkoxyalkyl having from 2 to 9 carbons, alkenyl having from 2 to 10 carbons;

wherein ring A 1 is independently 1,4-cyclohexylene, 1,4-phenylene, 2-fluoro-1,4-phenylene or 2,3-difluoro-1,4-phenylene;

wherein Z 1 is independently a single bond or —(CH 2 ) 2 —; W is —(CH 2 ) 4 —, —CH 2 O—, —OCH 2 —, —CH═CH— or —C≡C—;

wherein Y 1 is independently fluorine, hydrogen, —CF 2 H or —CF 3 , but wherein at least one of Y 1 is —CF 2 H or —CF 3 ; and

wherein Rc is —CH 3 .

11. The compound according to claim 7 , wherein in the formulae (1-1) to (1-6), W is —CH 2 O—; and

wherein Y 1 is independently —CF 3 or —CF 2 H.

12. The compound according to claim 8 , wherein in the formulae (1-1) to (1-6), Ra and Rb are independently alkyl having from 1 to 10 carbons, alkoxy having from 1 to 9 carbons, alkoxyalkyl having from 2 to 9 carbons, alkenyl having from 2 to 10 carbons, —CH 2 F or —OCH 2 F;

wherein ring A 1 is independently 1,4-cyclohexylene, 1,4-phenylene, 2-fluoro-1,4-phenylene, 2,3-difluoro-1,4-phenylene, 2,5-difluoro-1,4-phenylene or 2,6-difluoro-1,4-phenylene;

wherein Z 1 is independently a single bond, —(CH 2 ) 2 —, —COO—, —OCO—, —CH 2 O—, —OCH 2 —,, —CF 2 O—, —OCF 2 —, —CH═CH— or —C≡C—; wherein Y 1 is independently fluorine, chlorine, —CF 3 or —CHF 2 , but wherein at least one of Y 1 is chlorine, —CF 3 or —CHF 2 ; and

wherein Rc is alkyl.

13. The compound according to claim 8 , wherein in the formulae (1-1) to (1-6), Ra and Rb are independently alkyl having from 1 to 8 carbons, alkoxy having from 1 to 7 carbons, alkoxyalkyl having from 2 to 7 carbons or alkenyl having from 2 to 8 carbons;

wherein ring A 1 is independently 1,4-cyclohexylene, 1,4-phenylene, 2-fluoro-1,4-phenylene or 2,3-difluoro-1,4-phenylene;

wherein Z 1 is independently a single bond or —(CH 2 ) 2 —;

wherein Y 1 is independently hydrogen, fluorine or —CF 3 , but wherein at least one of Y 1 is —CF 3 ; and wherein Rc is CH 3 .

14. A compound represented by any one of the following formulae (I) to (IX):

wherein Ra and Rb are independently alkyl having from 1 to 10 carbons, wherein arbitrary —CH 2 — in the alkyl may be replaced by —O—, and wherein arbitrary —(CH 2 ) 2 — in the alkyl may be replaced by —CH═CH—;

wherein Z 1 is independently a single bond, —(CH 2 ) 2 —, —COO—, —OCO—, —CH 2 O—, —OCH 2 —, —CF 2 O—, —OCF 2 —, —CH═CH—, —CF═CF—, —C≡C—, —(CH 2 ) 2 COO—, —OCO(CH 2 ) 2 —, —(CH 2 ) 2 CF 2 O—, —(CH 2 ) 3 O—, —O(CH 2 ) 3 — or —(CH 2 ) 4 —;

wherein W is —(CH 2 ) 2 —, —(CH 2 ) 4 —, —CH 2 O—, —OCH 2 —, —CH═CH— or —C≡C—; and

wherein Y 1 is independently hydrogen, fluorine, chlorine, —CF 3 or —CF 2 H, but wherein at least one of Y 1 is chlorine, —CF 3 , or —CF 2 H.

15. The compound according to claim 14 , wherein in the formulae (I) to (IX), Ra and Rb are independently alkyl having from 1 to 10 carbons, alkoxy having from 1 to 9 carbons or alkenyl having from 2 to 10 carbons;

wherein Z 1 is independently a single bond, —(CH 2 ) 2 —, —CH═CH— or —(CH 2 ) 4 —;

wherein W is —CH 2 O— or —CH═CH—; and

wherein Y 1 is independently hydrogen, fluorine, chlorine, —CF 3 , or —CHF 2 , but wherein at least one of Y 1 is chlorine, —CF 3 , or —CHF 2 .

16. The compound according to claim 14 , wherein in the formulae (I) to (IX), Ra and Rb are independently alkyl having from 1 to 10 carbons, alkoxy having from 1 to 9 carbons or alkenyl having from 2 to 10 carbons;

wherein Z 1 is independently a single bond, —(CH 2 ) 2 —, —CH═CH— or —(CH 2 ) 4 —;

wherein W is —(CH 2 ) 2 —; and

wherein Y 1 are independently hydrogen, fluorine, —CF 3 or —CF 2 H, but wherein at least one of Y 1 is —CF 3 or —CF 2 H.

17. The compound according to claim 15 , wherein in the formulae (I) to (IX), Z 1 is independently a single bond or —CH═CH—;

wherein W is —CH 2 O—; and

wherein Y 1 is independently hydrogen, fluorine or —CF 3 , but wherein at least one of Y 1 is —CF 3 .

18. The compound according to claim 15 , wherein in the formulae (I) to (IX), Z 1 is a single bond; and wherein Y 1 is independently fluorine or —CF 3 , but wherein at least one of Y 1 is —CF 3 .

19. The compound according to claim 15 , wherein in the formulae (I) to (IX), Z 1 is a single bond; and wherein each Y 1 is —CF 3 .

20. A liquid crystal composition comprising at least one compound according to claim 1 .

21. The liquid crystal composition according to claim 20 , wherein the liquid crystal composition further comprises at least one compound represented by formulae (2), (3) and (4):

wherein R 1 is alkyl having from 1 to 10 carbons, wherein arbitrary —CH 2 — in the alkyl may be replaced by —O— or —CH═CH—, and wherein arbitrary hydrogen may be replaced by fluorine;

wherein X 1 is fluorine, chlorine, —OCF 3 , —OCHF 2 , —CF 3 , —CHF 2 , —CH 2 F, —OCF 2 CHF 2 or —OCF 2 CHFCF 3 ;

wherein ring B is independently 1,4-cyclohexylene, 1,3-dioxane-2,5-diyl or 1,4-phenylene, wherein arbitrary hydrogen of ring B may be replaced by fluorine;

wherein ring E is 1,4-cyclohexylene or 1,4-phenylene, wherein arbitrary hydrogen of ring E may be replaced by fluorine;

wherein Z 4 is independently —(CH 2 ) 2 —, —(CH 2 ) 4 —, —COO—, —CF 2 O—, —OCF 2 —, —CH═CH— or a single bond; and

wherein L 1 is independently hydrogen or fluorine.

22. The liquid crystal composition according to claim 20 , wherein the liquid crystal composition further comprises at least one compound represented by formulae (5) and (6):

wherein R 1 is alkyl having from 1 to 10 carbons, wherein arbitrary —CH 2 — in the alkyl may be replaced by —O— or —CH═CH—, and wherein arbitrary hydrogen may be replaced by fluorine;

wherein X 2 is —CN or —C≡C—CN;

wherein ring G is 1,4-cyclohexylene, 1,4-phenylene, 1,3-dioxane-2,5-diyl or pyrimidine-2,5-diyl;

wherein ring J is 1,4-cyclohexylene, pyrimidine-2,5-diyl or 1,4-phenylene, wherein arbitrary hydrogen of ring J may be replaced by fluorine;

wherein ring K is 1,4-cyclohexylene or 1,4-phenylene; Z 5 is —(CH 2 ) 2 —, —COO—, —CF 2 O—, —OCF 2 — or a single bond;

wherein L 1 is independently hydrogen or fluorine; and

wherein b is independently 0 or 1.

23. The liquid crystal composition according to claim 20 , wherein the liquid crystal composition further comprises at least one compound represented by formulae (7), (8), (9), (10) and (11):

wherein R 1 is alkyl having from 1 to 10 carbons, wherein arbitrary —CH 2 — in the alkyl may be replaced by —O— or —CH═CH—, and wherein arbitrary hydrogen may be replaced by fluorine;

wherein R 2 is fluorine or alkyl having from 1 to 10 carbons, wherein arbitrary —CH 2 — in the alkyl may be replaced by —O— or —CH═CH—, and wherein arbitrary hydrogen may be replaced by fluorine;

wherein ring M is independently 1,4-cyclohexylene, 1,4-phenylene or decahydro-2,6-naphthalene;

wherein Z 6 is independently —(CH 2 ) 2 —, —COO— or a single bond; and

wherein L 2 is independently hydrogen or fluorine, but wherein at least one of L 2 is fluorine.

24. The liquid crystal composition according to claim 20 , wherein the liquid crystal composition further comprises at least one compound represented by formulae (12), (13) and (14):

wherein R 1 is alkyl having from 1 to 10 carbons, wherein arbitrary —CH 2 — in the alkyl may be replaced by —O— or —CH═CH—, and wherein arbitrary hydrogen may be replaced by fluorine;

wherein ring J is independently 1,4-cyclohexylene, pyrimidine-2,5-diyl or 1,4-phenylene, wherein arbitrary hydrogen of ring J may be replaced by fluorine; and

wherein Z 7 is independently —C≡C—, —COO—, —(CH 2 ) 2 —, —CH═CH— or a single bond.

25. The liquid crystal composition according to claim 21 , wherein the liquid crystal composition further comprises at least one compound represented by formulae (5) and (6):

wherein R 1 is alkyl having from 1 to 10 carbons, wherein arbitrary —CH 2 — in the alkyl may be replaced by —O— or —CH═CH—, and wherein arbitrary hydrogen may be replaced by fluorine;

wherein X 2 is —CN or —C≡C—CN;

wherein ring G is 1,4-cyclohexylene, 1,4-phenylene, 1,3-dioxane-2,5-diyi or pyrimidine -2,5-diyl;

wherein ring J is 1,4-cyclohexylene, pyrimidine-2,5-diyl or 1,4-phenylene, wherein arbitrary hydrogen of ring J may be replaced by fluorine;

wherein ring K is 1,4-cyclohexylene or 1,4-phenylene; Z 5 is —(CH 2 ) 2 —, —COO—, —CF 2 O—, —OCF 2 — or a single bond;

wherein L 1 is independently hydrogen or fluorine; and

wherein b is independently 0 or 1.

26. The liquid crystal composition according to claim 21 , wherein the liquid crystal composition further comprises at least one compound represented by formulae (12), (13) and (14):

wherein R 1 is alkyl having from 1 to 10 carbons, wherein arbitrary —CH 2 — in the alkyl may be replaced by —O— or —CH═CH—, and wherein arbitrary hydrogen may be replaced by fluorine;

wherein ring J is independently 1,4-cyclohexylene, pyrimidine-2,5-diyl or 1,4-phenylene, wherein arbitrary hydrogen of ring J may be replaced by fluorine; and

wherein Z 7 is independently —C≡C—, —COO—, —(CH 2 ) 2 —, —CH═CH— or a single bond.

27. The liquid crystal composition according to claim 22 , wherein the liquid crystal composition further comprises at least one compound represented by formulae (12), (13) and (14):

wherein R 1 is alkyl having from 1 to 10 carbons, wherein arbitrary —CH 2 — in the alkyl may be replaced by —O— or —CH═CH—, and wherein arbitrary hydrogen may be replaced by fluorine;

wherein ring J is independently 1,4-cyclohexylene, pyrimidine-2,5-diyl or 1,4-phenylene, wherein arbitrary hydrogen of ring J may be replaced by fluorine; and

wherein Z 7 is independently —C≡C—, —COO—, —(CH 2 ) 2 —, —CH═CH— or a single bond.

28. The liquid crystal composition according to claim 23 , wherein the liquid crystal composition further comprises at least one compound represented by formulae (12), (13) and (14):

wherein R 1 is alkyl having from 1 to 10 carbons, wherein arbitrary —CH 2 — in the alkyl may be replaced by —O— or —CH═CH—, and wherein arbitrary hydrogen may be replaced by fluorine;

wherein ring J is independently 1,4-cyclohexylene, pyrimidine-2,5-diyl or 1,4-phenylene, wherein arbitrary hydrogen of ring J may be replaced by fluorine; and

wherein Z 7 is independently —C≡C—, —COO—, —(CH 2 ) 2 —, —CH═CH— or a single bond.

29. The liquid crystal composition according to claim 20 , wherein the liquid crystal composition further comprises at least one optically active compound.

30. A liquid crystal display device comprising at least one liquid crystal composition according to claim 20 .