High polarization dopants for ferroelectric liquid crystal compositions

• US 6,838,128 B1
• Filed: 02/05/2002
• Issued: 01/04/2005
• Est. Priority Date: 02/05/2002
• Status: Expired due to Fees

• Current Assignee: Citizen Finedevice Co., Ltd. (Citizen Electronics Company Limited)
• Original Assignee: DT FLCO, Inc. (Micron Technology, Inc.)
• Inventors: Chen, Xin Hua, Wand, Michael
• Primary Examiner(s): WU, SHEAN CHIU
• Application Number:
  US10/068,557
• Time in Patent Office: 1,064 Days
• Field of Search: 252/299.61, 252/299.62, 252/299.63, 252/299.66, 252/299.67, 252/299.01, 544/329, 544/333, 546268-283, 549/313, 549/318, 549/319, 428/1.1
• US Class Current: 428/1.1
• CPC Class Codes: C07D 213/65 attached in position 3 or 5
• CPC Class Codes: C07D 239/26 with only hydrogen atoms, hydrocarbon or substituted hydrocarbon radicals, directly attached to ring carbon atoms
• CPC Class Codes: C07D 307/33 in position 2, the oxygen atom being in its keto or unsubstituted enol form
• CPC Class Codes: C07D 405/12 linked by a chain containing hetero atoms as chain links
• CPC Class Codes: C09K 19/0225 Ferroelectric
• CPC Class Codes: C09K 19/3405 the heterocyclic ring being a five-membered ring
• CPC Class Codes: C09K 19/588 Heterocyclic compounds
• CPC Class Codes: C09K 2323/00 Functional layers of liquid crystal optical display excluding electroactive liquid crystal layer characterised by chemical composition

Abstract

The invention relates to chiral nonracemic liquid crystal compounds which are useful as components in liquid crystal compositions to impart high polarization to the mixture. The materials of this invention can be combined with liquid crystal host materials to impart improved properties to mixtures. Chiral nonracemic compounds of this invention can function as additives or dopants in host materials to impart chirality into an LC material. Most generally the invention provides mixtures containing one or more chiral nonracemic dopants which have a chiral nonracemic tail that is an optionally substituted α-ester γ-lactone of the formula:

where * indicates a chiral carbon; R₁ is a straight-chain or branched alkyl or alkenyl group wherein one or more non-neighboring carbon atoms can be replaced with an oxygen atom and wherein one or more carbons can be substituted with one or more halogens; R₂ and R₃, independently of one another, can be hydrogen, a halogen or a lower alkyl or alkenyl group; and X is hydrogen or a lower alkyl group. LC compounds having a chiral nonracemic tail of this general formula have large dipoles (and large spontaneous polarization (P_s)) and when doped into hosts such as achiral smectic C FLC hosts, lead to improved switching speeds of the FLC materials.

Claims

1. A liquid crystal composition comprising one or more chiral nonracemic compounds of formula:

where the substituents between Z and G represent the core;

where G is a chiral nonracemic optionally substituted α

-ester γ

-lactone of formula;

where * indicates a chiral carbon, R₁ is a straight-chain or branched alkyl or alkenyl group wherein one or more non-neighboring carbon atoms can be replaced with an oxygen atom and wherein one or more carbons can be substituted with one or more halogens;

R₂ and R₃, independently of one another, can be H, halogen or a lower alkyl or alkenyl group;

X is H, or a lower alkyl group;

R is selected from the group consisting of;

(1) an achiral straight chain or branched silane or siloxane having one or more silicon atoms and which may be substituted with one or more halogens

(2) an achiral linear or branched perfluorinated or partially fluorinated alkyl group (R^F);

(3) an achiral linear, cyclic or branched perfluorinated or partially fluorinated ether group;

(4) an achiral linear or branched ether having one or more oxygen atoms and which may be substituted with one or more halogens;

(5) an achiral alkyl, alkenyl or alkynyl group which may be substituted with one of more halogens;

(6) or a straight chain or branched thioether having one or more sulfur atoms and which may be substituted with one or more halogens.

and where;

Z is a linker selected from the group consisting of O, CO, OOC, COO, S or a single bond;

core rings A, B and C can be aromatic or alicyclic;

if aromatic, one or two ring carbons can be replaced with a nitrogen;

or if alicyclic, rings can contain 3-10 carbon atoms and optionally can contain a double bond, wherein one or two CH₂ of the alicyclic ring can be replaced with a nitrogen, sulfur, or oxygen atom, or a C═

O group;

Y represents up to four substituents on a given ring when the ring is aromatic and up to 20 substituents when the ring is alicyclic, where substituents are selected from halides, CN, NO₂, alkyl or alkoxy;

linkers A and B, independently, are selected from the group consisting of a single bond, —

COO—

, —

OOC—

, —

CH₂—

CH₂—

, —

OCH₂—

, —

CH₂—

O—

, —

CH═

CH—

(cis or trans);

—

C═

C—

, and —

CH═

CH—

CH═

CH—

(cis or trans);

and where a and b are integers that are 0 or 1 and where a+b is 1 or 2;

wherein when X is H, R is not an achiral linear partially fluorinated ether group.

2. The liquid crystal composition of claim 1 wherein the core is selected from the group consisting of:

3. The liquid crystal composition of claim 1 wherein the core rings A, B and C are selected from the group consisting of phenyls, pyridines, pyrimidines and cyclohexanes.

4. The liquid crystal composition of claim 1 wherein the core is selected from the group consisting of biphenyl;

dioxane;

optionally substituted phenyl, optionally substituted cyclohexyl, optionally substituted cyclohexenyl, where one or more ring carbons is substituted with O, N or S;

phenyl benzoate;

phenylpyridine; and

phenylpyrimidines.

5. The liquid crystal composition of claim 2 wherein R₁ is a straight-chain or branched alkyl or alkenyl group wherein one or more non-neighboring carbon atoms can be replaced with an oxygen atom and wherein one or more carbons can be substituted with one or more halogens.

6. The liquid crystal composition of claim 5 wherein R₂ and R₃, independently of one another, can be H, halogen or a lower alkyl or alkenyl group.

7. The liquid crystal composition of claim 6 wherein X is H, or a lower alkyl group.

8. The liquid crystal composition of claim 7 wherein Z is —

O—

or a single bond.

9. The liquid crystal composition of claim 8 wherein R is an ether, a partially fluorinated ether, or a perfluorinated ether.

10. The liquid crystal composition of claim 8 wherein R is R^F and where R^F is an achiral linear or branched perfluorinated or partially fluorinated alkyl group.

11. The liquid crystal composition of claim 10 wherein R^F has the formula:

C_nF_2n+1C_mH_2m wherein n is an integer ranging from 1 to 20 and m is an integer ranging from 1 to 20.

12. The liquid crystal composition of claim 10 wherein R^F has the formula:

C_nF_2n+1C_mH_2m wherein n is an integer ranging from 1 to 20 and m is an integer ranging from 0 to 20.

13. The liquid crystal composition of claim 7 wherein R is an achiral alkyl, alkenyl or alkynyl group having from 3 to 20 carbon atoms in which one or more of the non-neighboring carbons can be replaced with an oxygen, or in which one or more of the carbons is substituted with one of more halogens.

14. The liquid crystal composition of claim 8 wherein R is an achiral silane:

where;

R⁴ is a straight chain or branched alkyl or alkenyl group having one or more carbon atoms and R₅, R_5′

, R₆ and R_6′

, independently of one another, are alkyl groups having from 1-6 carbon atoms;

n1 and m are integers from 1 to 20;

n2 can be zero or an integer from 1 to 20 where the dashed line indicates a possible double or triple bond;

k is 0 or an integer from 1 to 10.

15. The liquid crystal composition of claim 1 wherein R is R^F and where R^F is an achiral linear or branched perfluorinated or partially fluorinated alkyl group.

16. The liquid crystal composition of claim 15 wherein R^F has the formula:

C_nF_2n+1C_mH_2m wherein n is an integer ranging from 1 to 10 and m is an integer ranging from 1 to 10.

17. The liquid crystal composition of claim 16 wherein R^F is C₄F₉C₄H₈.

18. The liquid crystal composition of claim 17 wherein X is H.

19. The liquid crystal composition of claim 18 wherein the core is

20. The liquid crystal composition of claim 19 wherein R₁ is C₃H₇.

21. The liquid crystal composition of claim 20 wherein X is H.

22. The liquid crystal composition of claim 20 wherein X is CH₃.

23. The liquid crystal composition of claim 1 having a Ps of at least 5 nC/cm².

24. The liquid crystal composition of claim 1 which exhibits a smectic C phase.

25. The liquid crystal composition of claim 1 which can be oriented within an achiral ferroelectric liquid crystal material.

26. A device comprising the liquid crystal composition of claim 1 oriented within an achiral ferroelectric liquid crystal layer exhibiting a smectic C Phase.

27. A liquid crystal compound having the formula:

where the substituents between Z and G represent the core;

where G is a chiral nonracemic optionally substituted α

-ester γ

-lactone of formula;

where * indicates a chiral carbon, R₁ is a straight-chain or branched alkyl or alkenyl group wherein one or more non-neighboring carbon atoms can be replaced with an oxygen atom and wherein one or more carbons can be substituted with one or more halogens;

R₂ and R₃, independently of one another, can be H, halogen or a lower alkyl or alkenyl group;

X is H, or a lower alkyl group;

R is selected from the group consisting of;

(1) an achiral straight chain or branched silane or siloxane having one or more silicon atoms and which may be substituted with one or more halogens

(2) an achiral linear or branched perfluorinated or partially fluorinated alkyl group (R^F);

(3) an achiral linear, cyclic or branched perfluorinated or partially fluorinated ether group;

(4) an achiral linear or branched ether having one or more oxygen atoms and which may be substituted with one or more halogens;

(5) an achiral alkyl, alkenyl or alkynyl group which may be substituted with one of more halogens; and

(6) or a straight chain or branched thioether having one or more sulfur atoms and which may be substituted with one or more halogens;

and where;

Z is a linker selected from the group consisting of O, CO, OOC, COO, S or a single bond;

core rings A, B and C can be aromatic or alicyclic, if aromatic, one or two ring carbons can be replaced with a nitrogen or if alicyclic rings can contain 3-10 carbon atoms and optionally can contain a double bond, wherein one or two CH₂ of the alicyclic ring can be replaced with a nitrogen, sulfur, or oxygen atom, or a C═

O group;

Y represents up to four substituents on a given ring when the ring is aromatic and up to 20 substituents when the ring is alicyclic, where substituents are selected from halides, CN, NO₂, alkyl or alkoxy;

linkers A and B, independently, are selected from the group consisting of a single bond, —

COO—

, —

OOC, —

CH₂—

CH₂—

, —

OCH₂—

, —

CH₂—

O—

, —

CH═

CH—

(cis or trans);

—

C≡

C—

, and —

CH═

CH—

CH═

CH—

(cisor trans);

and where a and b are integers that are 0 or 1 and where a+b is 1 or 2;

wherein when X is H, R is not an achiral linear partially fluorinated ether group.

28. The liquid crystal compound of claim 27 wherein R is R^F.

29. The liquid crystal compound of claim 28 wherein R^F has the formula:

C_nF_2n+1C_mH_2m wherein n is an integer ranging from 1 to 10 and m is an integer ranging from 1 to 10.

30. The liquid crystal compound of claim 29 wherein R^F is C₄F₉C₄H₈.

31. The liquid crystal compound of claim 30 wherein X is H.

32. The liquid crystal compound of claim 31 wherein the core is

33. The liquid crystal compound of claim 32 wherein R₁ is C₃H₇.

34. The liquid crystal compound of claim 33 wherein X is H.

35. The liquid crystal compound of claim 34 wherein X is CH₃.

40. A liquid crystal device comprising a composition of one or more of the compounds of claim 27.

41. A ferroelectric liquid crystal device comprising an achiral smectic C liquid crystal host doped with from 1 to about 100% by weight of the compound of claim 27.

42. A ferroelectric liquid crystal device comprising an achiral smectic C liquid crystal host doped with from 1 to about 50% by weight of the compound of claim 27.

43. A ferroelectric liquid crystal device comprising an achiral smectic C liquid crystal host doped with from 1 to about 15% by weight of the compound of claim 27.

36. A liquid crystal compound having the formula:

37. A liquid crystal compound having the formula:

38. A liquid crystal compound having the formula:

39. A liquid crystal compound having the formula:

44. A polysiloxane having chiral mesogenic side chains, the polysiloxane having the formula:

wherein D is an alkyl group having from 1 to 3 carbon atoms;

n is either 0 or 1 and when y=0, m is a number ranging from 10 to 100 and when y=1, m is an integer ranging from 4 to 10 and wherein M is a chiral nonracemic mesogenic group having the formula;

wherein where G is an optionally substituted α

-ester γ

-lactone having the formula;

where R₁ is a straight-chain or branched alkyl or alkenyl group wherein one or more non-neighboring carbon atoms can be replaced with an oxygen atom and wherein one or more carbons can be substituted with one or more halogens;

R₂ and R₃, independently of one another, can be H, halogen or a lower alkyl or alkenyl group;

X is H, or a lower alkyl group;

where R is a straight chain alkyl group having from about 6 to about 12 carbon atoms;

Z is O or a single bond;

core rings A, B and C can be aromatic or alicyclic;

if aromatic one or two ring carbons can be replaced with a heteroatom;

or if alicyclic, rings can contain 3-10 carbon atoms and optionally can contain a double bond, wherein one or two CH₂ of the alicyclic ring can be replaced with N, S, O or a C═

O group;

Y represents up to four substituents on a given ring when the ring is aromatic and up to 0 substituents when the ring is alicyclic, where substituents are selected from halides, CN, NO₂, alkyl or alkoxy;

linkers A and B, independently, are selected from the group consisting of a single bond, —

COO—

, —

OOC, —

CH₂—

CH₂—

, —

OCH₂—

, —

CH₂—

O—

, —

CH═

CH—

(cis or trans);

—

C≡

C—

, —

CH═

CH—

CH═

CH—

(cis or trans);

and where a and b are integers that are 0 or 1 and where a+b is 1 or 2.