KR100314366B1 - Antiferroelectric Liquid Crystal Display Device and Antiferroelectric compounds and Compositions for Use Therein - Google Patents

Abstract

The present invention discloses a semiferroelectric liquid crystal device in which the liquid crystal layer comprises at least one compound represented by the following Chemical Formula 106. The present invention also discloses a novel compound of formula 106 wherein X is F and a process for preparing the compound.

Wherein a is 1 to 16, b is 1 or 2, c is 1 to 14, n, p and r are each independently 0 or 1, and rings A and B are each independently cyclohexyl, non Ring phenyl, mono-fluorophenyl, difluorophenyl, dioxanyl, pyrimidyl and pyridinyl, X is H or F, and Y and Z are each independently CC, C≡ C, CO ₂ , O ₂ C and O, and (*) represents an asymmetric carbon atom.

Description

Antiferroelectric liquid crystal display device and antiferroelectric compounds and compositions for use therein

The present invention relates to antiferroelectric display devices and antiferroelectric compounds and compositions for use in the devices.

Many compounds which show a liquid crystal phase under appropriate conditions are synthesized. In the case of real liquid crystal display devices, these compounds (usually in mixtures with other compounds) are necessary to give the display a wide viewing angle, large contrast ratio, fast response and low voltage operation.

S. Inui et al., J. Mater. Chem. 1996 6 (4) pp. 671-673 disclose a series of compounds of formula (101). Three-component mixtures of these compounds exhibit tilt angles above 35 °, contrast ratios below 100, wide viewing angles above 60 °, and no critical AF-F transitions.

(CJ Booth et al., Liquid Crystals 1996 20 (6) pp. 815-823) disclose compounds of formula 102, wherein A = CH ₂ F and B = CH ₂ OC ₆ H ₁₃ are antiferroelectric phases. Not shown.

Wherein A = alkyl or fluoroalkyl, B = alkyl or CH ₂ O-alkyl.

Japanese Patent Nos. 7-252479, 8-218070, 9-157224 and 7-316100 have aliphatic end chains at each opposite end of the molecule, and a fluoromethyl group and an alkoxyalkyl group bonded to chiral carbon. Similar compounds with biphenyl-carbonyloxy-phenyl cores having chiral end chains are disclosed. These compounds exhibit antiferroelectric behavior (characterized by the presence of chiral smectic C _A (S _A ) phases) and have a fast switching time. Example 1 of Japanese Patent No. 7-316100 having a chiral side chain of CH (CF ₃ ) (CH ₂ ) ₅ OC ₂ H ₅ has a S _A phase range of 43 to 93 ° C. and a tilt angle of 32 °. Japanese Patent No. 8-218069 also discloses a similar compound and a compound in which a biphenyl group is replaced with a 1,3-dioxan-2-yl phenyl group.

EP 0617109 discloses a series of tetralin based liquid crystal materials having chiral end chains. Certain examples in which the chiral side chain contains ethers (Formula 103) show a narrow antiferroelectric phase.

International Patent Publication Nos. 96/30330 and 6-228056 also disclose similar tetralin based liquid crystal materials having trifluoromethyl and alkoxyalkyl groups bonded to chiral (*) carbons.

SL Wu, Liquid Crystals 1995 18 (5) pp. 715-721 discloses a series of compounds of formula All compounds exhibit an S _A phase (the widest S _A phase range is 83 to 140 ° C. for m = 12).

EP-A-0360622 and US-A-5693251 disclose a wide variety of liquid crystal compounds that may be useful in ferroelectric liquid crystal displays. Among these compounds,

Compounds of are disclosed.

However, it is not suggested that these compounds can exhibit antiferroelectric phases.

EP-A-0357435 also discloses a wide range of liquid crystal compounds that can be useful in ferroelectric liquid crystal displays. Among these compounds,

Compounds of are disclosed.

However, the presence of antiferroelectric phases is not proposed.

Japanese Patent Laid-Open No. 63210848 discloses a compound of formula 105 useful as a ferroelectric liquid crystal.

Wherein R ₁ is C _6-12 alkyl, R ₂ is C _3-5 optically active group, R ₃ is C _1-6 alkyl and n is 0 or 1.

In particular, this document includes

Compounds of are disclosed.

However, the presence of antiferroelectric phases in these compounds is not disclosed.

It is an object of the present invention to provide a novel antiferroelectric liquid crystal device.

1 to 5 are graphs plotting the cone angle versus temperature for various compounds used in the present invention.

6 is a schematic diagram of a typical cell (pixel) portion of an active matrix array in one example of a liquid crystal element in accordance with the present invention.

7A and 7B show alternate switching waveforms used in the addressing scheme for an array in the device of FIG. 6.

8 and 9 illustrate alternate active circuits for addressing an array.

<Explanation of symbols for the main parts of the drawings>

(2), (4): transparent substrate (6): gap between substrates

(8): transparent electrode (9): array layer

(10): matrix array (12): data driver

14: scan driver 18 transistors

(20): electrode (22): data electrode

(24): capacitor (28): buffer amplifier

The first aspect of the invention includes a pair of substrates, a layer of antiferroelectric liquid crystal material disposed between the substrates, and voltage application means for applying a voltage across the layer to control the formation of the antiferroelectric phase in the layer. As providing a liquid crystal device, the anti-ferroelectric material is characterized in that it comprises a compound of the formula (106).

<Formula 106>

Wherein a is 1 to 16, b is 1 or 2, c is 1 to 14, n, p and r are each independently 0 or 1, and rings A and B are each independently cyclohexyl, non Ring phenyl, mono-fluorophenyl, difluorophenyl, dioxanyl, pyrimidyl and pyridinyl, X is H or F, and Y and Z are each independently CC, C≡ C, CO ₂ , O ₂ C and O, and (*) represents an asymmetric carbon atom.

Due to the asymmetric carbon center (*), there is a pair of enantiomers for each structure represented by formula (106).

Preferably, c is 1 to 11 (more preferably 1 to 5) and / or n is 1 and ring A is unsubstituted phenyl and ring B is unsubstituted phenyl X is H and Y is CO ₂ and Z is CO ₂ .

More preferably, c is 1 to 5, rings A and B are each unsubstituted phenyl, X is H, Y and Z are each CO ₂ and n is 1.

Preferably, the compound of formula 106 exhibits antiferroelectric behavior. This antiferroelectric behavior is characterized by the presence of chiral smectic C _A (S _A ) phases.

More preferably, the S _A phase temperature range of the compound is above 70 ° C. and / or the compound may be present as an antiferroelectric S _A phase below 45 ° C.

Compounds can exhibit critical nonferroelectric behavior. This thresholdless antiferroelectric behavior is characterized by a spontaneous transition between antiferroelectric S _A phase and ferroelectric phase, for example S phase (eg, A. Fukuda, Proceedings of 15th International Display Research Conference, Asia Display). 1995 pp. 61-64 and S. Inui et al., Supra).

Preferably, the compound is capable of rapid switching from the dark state to the transmissive state (τ temperature: less than 0.65 ms, more preferably less than 0.4 ms) and / or rapid switching from the transmissive state to the dark state (τ off: 5.1 ms). Less than, more preferably less than 2.6 ms).

Preferably, the threshold voltage for changes in the transmission state is 5 V or less, more preferably less than 4 V.

Preferably, the compound exhibits nonlinear transmission behavior as the voltage changes near the threshold voltage such that the change in voltage results in a relatively small change in transmission. This is advantageous in overcoming the problem that, in the case of an error in the voltage applied to the liquid crystal pixels, the contrast is reduced due to the confusion of light leakage in the dark state in certain active matrix liquid crystal displays incorporating linear transmissive liquid crystal materials.

Preferably, the compound has a spontaneous polarization coefficient (P _S ) of less than 65 nC / cm 2, more preferably less than 55 nC / cm 2, most preferably less than 35 nC / cm 2.

The inventors have formulas wherein a is 12, b is 1, c is 1 to 5, n, p and r are each 1, rings A and B are unsubstituted phenyl and X is H and Y and Z are each CO ₂ Compound 106 was found to be an example of a compound exhibiting the broad range of antiferroelectric S _A phases described above, low switching time, voltage and polarization coefficient.

The second aspect of the present invention provides a compound of formula 106 as described above wherein (i) a chiral smectic C _A (S _A ) phase and / or having a fluorine group in at least one of X, ring A and ring B to provide.

Ring A and / or Ring B may be a phenyl group substituted by one or more fluorine atoms.

The third aspect of the present invention provides a stereoselective method for the preparation of a compound of formula

(i) converting the compound of formula 107a to the compound of formula 107b,

(ii) forming an ester bond between the compound of Formula 107b and the compound of Formula 107c to obtain a compound of Formula 107d,

(iii) converting B of the compound of formula 107d to H,

(iv) forming a ester bond between the unblocked compound of step (iii) and the compound of formula 107e to prepare a compound of formula 107.

Where

a is 1 to 16, b is 1 or 2,

c is 1 to 14, n is 0 or 1,

Rings A and B are each independently selected from the group consisting of cyclohexyl, unsubstituted phenyl, monofluorophenyl, difluorophenyl, dioxanyl, pyrimidyl and pyridinyl,

R is C _1-6 alkyl,

X is H or F,

B is a breaker.

The breaker B is not particularly limited and may be appropriately selected by those skilled in the art. Examples of suitable blockers include those described in TH Greene and PGM Wuts' Protective Groups in Organic Synthesis, 2nd Edition, 1991, John Wiley, for example methoxycarbonyl, benzyl and tetrahydropyranyl do.

While the above represents a preferred method, it will be appreciated that the same modifications can be made in different orders. For example, in the first step, an ester bond can be formed between a compound of formula 107e and a compound similar to the compound of formula 107c wherein B is H and CO ₂ H is suitably blocked. The method of the present invention is intended to include other similar modifications in which compounds similar to the compounds of Formulas 107a, 107c and 107e can be combined and modified to obtain compounds of Formula 107.

The present invention provides a method for preparing a compound of Formula 107, which method comprises reacting a compound of Formula 108 with a compound of Formula 109.

<Formula 107>

Wherein ring A, ring B, a, b, c, n and X are as defined above.

In addition, the present invention provides a method for preparing a compound of Formula 106a, which comprises reacting a compound of Formula 110 with a compound of Formula 111 or 112.

Where

a is 1 to 16,

b is 1 or 2,

c is 1 to 14,

n is 0 or 1,

Rings A and B are each independently selected from the group consisting of cyclohexyl, unsubstituted phenyl, monofluorophenyl, difluorophenyl, dioxanyl, pyrimidyl and pyridinyl,

X is H or F,

Z is CO ₂ or O,

(*) Represents an asymmetric carbon atom.

In the formula, Tf represents trifluoromethylsulfonyl.

A fourth aspect of the present invention provides a semiferroelectric liquid crystal composition comprising at least one compound selected from the compounds of the formula 106 in which at least one of them exhibits a chiral smectic C _A (S _A ) phase.

Embodiments of the present invention are described by way of example with reference to the accompanying drawings. As used herein, the term 'biph' or 'bipheny' means 'biphenyl' and 'benz' or 'benzoate' means 'benzoate'.

<Examples 1 to 6>

Scheme 1 summarizes the synthetic route used to obtain compounds 8a-8f of Formula 106. The following reaction conditions are described with reference only to Example 1, but it will be understood that similar conditions were used to obtain Examples 2-6.

Methyl (R) -3-benzyloxybutyrate (Compound 2)

9.3 (77.9 mmol) of (R) -3-methyl hydroxybutyrate (1), 23.68 g (93.8 mmol) of benzyl 2,2,2-trichloroacetimimate at room temperature under a dry nitrogen atmosphere at ), 104 mL of cyclohexane and 52 mL of dichloromethane were injected via a rubber stopper. For 20 minutes the color of the reaction turned from colorless to yellow, eventually forming a fine precipitate. After the reaction was stirred for an additional 60 minutes at room temperature, TLC analysis (9: 1 hexane-ethylacetate, 2 Rf = 0.36) showed no benzyl 2,2,2-trichloroacetimidate remaining. The precipitate (trichloroacetamide) was filtered off and the filtrate was washed sequentially with 100 mL of saturated sodium hydrogen carbonate, 2 x 100 mL of water, dried over MgSO ₄ , filtered under vacuum and evaporated to give a clear yellow oil. It was purified by flash chromatography (fine mesh silica gel; 9.2: 0.8 hexanes-ethyl acetate) to give a pale yellow oil which was dried under vacuum (P ₂ O ₅ , 10 mbar, room temperature, 72 h). Yield: 13.40 (82).

(R) -3- (benzyloxy) butan-1-ol (compound 3)

13.0 g (62.5 mmol) of compound 2 are dissolved in 100 ml of dry tetrahydrofuran, and added dropwise to 2.50 g (65.9 mmol) of a suspension of lithium aluminum hydride in 100 ml of dry tetrahydrofuran, and the reaction temperature is added dropwise 10 Kept between 20 ° C. After the addition was complete, the reaction was stirred for an additional 1.5 h at 7 ° C. and allowed to warm to rt overnight. TLC analysis (CH ₂ Cl ₂ ; Rf compound 2 = 0.30, Rf compound 2 = 0.66) showed no starting material remaining. 30 mL of ethyl acetate was added dropwise followed by 50 mL of water and 50 mL of 10 hydrochloric acid. The aqueous layer was separated and washed repeatedly with 5 x 100 mL of diethyl ether. HANDemo silver organic extracts were washed with 50 mL brine, dried over MgSO ₄ , filtered and evaporated to give a light oil. Flash chromatography [micro mesh silica gel; Dichloromethane (initial) and 9: 1 dichloromethane-diethylether (final)] to give a light oil that is dried under vacuum (P ₂ O ₅ , 0.1 mbar, room temperature, 5 hours). Yield = 9.11 g (81).

(R) -3- (benzyloxy) -1-methoxybutane (Compound 4a)

1.59 g (11.2 mmol) of methyliodide in 20 mL of dry dimethylformamide are stirred at 20 ° C. in dry dimethylformamide at room temperature under stirring of 0.68 g (60 dispersions) of sodium hydride and 1.80 g (10.0 mmol) of compound 3 To the prepared suspension. The reaction was stirred for about 48 hours and 30 ml of water was carefully added to destroy excess sodium hydride. The reaction mixture was diluted with 100 mL dichloromethane and the organic phase was separated. The aqueous phase was washed with 3 x 50 mL of dichloromethane. HANDemo silver organic extract was washed in the order of 50 ml of 10 hydrochloric acid, 50 ml of saturated sodium bicarbonate and 50 ml of brine, dried over MgSO ₄ , filtered and evaporated to give a yellow oil. It was purified by flash chromatography (fine mesh silica gel; 4 (v / v) ethyl acetate in hexane) to give a colorless liquid which was dried under vacuum. Yield = 1.49 g (76).

(R) -3- (benzyloxy) -1-ethoxybutane (Compound 4b)

Yield 1.32 g (63).

(R) -3- (benzyloxy) -1-butoxybutane (Compound 4c)

Yield 1.33 g (56).

(R) -3- (benzyloxy) -1-pentoxybutane (Compound 4d)

Yield 0.99 g (51).

(R) -3- (benzyloxy) -1-dodecyloxybutane (Compound 4e)

Yield 2.07 g (53).

(R) -3-benzyloxy-1-tetradecyloxybutane (Compound 4f)

Yield = 3.09 g

(R) -4-methoxybutan-2-ol (compound 5a)

1.42 g (7.3 mmol) of compound 4a were dissolved in 58 ml of ethanol and 30 ml of cyclohexene, and 0.22 g of palladium hydroxide on graphite (20 minutes dispersion) was added. The resulting suspension was heated at reflux (about 90 ° C.) for 6 hours. GC analysis of the reaction mixture showed no starting material 4a remaining (GC conditions were maintained at injection 220 ° C., detection 300 ° C., oven 80 ° C. for 1 minute, increase to 30 ° C. per minute to 250 ° C., Rf 4a = 6.76 min, Rf 5a = 2.17 min). The cooled reaction mixture is filtered through a pad of Hyflo-Supercel® and the filtrate is evaporated to remove all solvents to give a colorless liquid, further optionally with Kugelrohr distillation. Can be purified by The product was dried under vacuum (P ₂ O ₅ , 10 mbar, room temperature, 18 h). Yield = 0.47 g (62).

(R) -4-ethoxybutan-2-ol (Compound 5b)

Yield = 0.58 g (82).

(R) -4-butoxybutan-2-ol (Compound 5c)

Yield = 0.46 g (61).

(R) -4-pentoxybutan-2-ol (compound 5d)

Yield = 0.46 g (92).

(R) -4-dodecyloxybutan-2-ol (compound 5e)

Yield = 1.47 g (100).

(R) -4-tetradecyloxybutan-2-ol (compound 5f)

Yield = 2.28 g (100).

(S) -2- (4-methoxy) butyl 4-methoxycarbonyloxybenzoate (Compound 6a)

A solution of 0.44 g (4.2 mmol) of compound 5a and 0.73 g (2.8 mmol) of triphenylphosphine in 20 ml of dry tetrahydrofuran was dried at room temperature under a dry nitrogen atmosphere at 0.50 diethyl azodicarboxylate in 15 ml of tetrahydrofuran. g (2.8 mmol) and 0.55 g (2.8 mmol) of 4-methoxycarbonyloxybenzoic acid were added dropwise. The yellow reaction mixture was drained for about 10 minutes and the reaction mixture was left to stir for an additional 18 hours. The reaction mixture is diluted with 150 ml of diethyl ether, filtered through a pad of Hyflo-Supercell®, the filtrate is washed with 50 ml of brine, dried over MgSO ₄ , filtered and evaporated to a colorless oil. Got. This was followed by flash chromatography [micro mesh silica gel; 9: 1 dichloromethane-ethyl acetate] to give a colorless oil which was dried under vacuum (P ₂ O ₅ , 10 mbar, room temperature, 5 h). Yield = 0.49 g (62).

(S) -2- (4-ethoxy) butyl 4-methoxycarbonyloxybenzoate (Compound 6b)

Yield = 0.68 g (67).

(S) -2- (4-butoxy) butyl 4-methoxycarbonyloxybenzoate (Compound 6c)

Yield = 0.44 g (44).

(S) -2- (4-pentoxy) butyl 4-methoxycarbonyloxybenzoate (Compound 6d)

Yield = 0.45 g (73).

(S) -2- (4-dodecyloxy) butyl 4-methoxycarbonyloxybenzoate (Compound 6e)

Yield = 1.10 g (66).

(S) -2- (4-tetradecyloxy) butyl 4-methoxycarbonyloxybenzoate (Compound 6f)

Yield = 1.86 g (76).

(S) -2- (4-methoxy) butyl 4-hydroxybenzoate (Compound 7a)

0.39 g (1.4 mmol) of compound 6a was dissolved in 15 mL of ethanol, and 7.0 mL (specific gravity 0.88) of ammonia was added dropwise while stirring at room temperature. The reaction was left to stir for an additional 48 hours. TLC analysis (dichloromethane) showed no starting material remaining. The reaction was poured into 100 mL of water with stirring and the extracted product was washed with 4 x 50 mL of diethyl ether. Handemo was washed with 20 ml of ethereal extract, dried over MgSO ₄ , filtered and evaporated to give a colorless oil and dried under vacuum (P ₂ O ₅ , 10 mbar, room temperature, 4 hours). Yield = 0.31 g (100).

(S) -2- (4-ethoxy) butyl-4-hydroxybenzoate (Compound 7b)

Yield = 0.50 g (100).

(S) -2- (4-butoxy) butyl-4-hydroxybenzoate (Compound 7c)

Yield = 0.35 g (100).

(S) -2- (4-pentoxy) butyl-4-hydroxybenzoate (Compound 7d)

Yield = 0.24 g (72).

(S) -2- (4-dodecyloxy) butyl-4-hydroxybenzoate (Compound 7e)

Yield = 0.95 g (100).

(S) -2- (4-tetradecyloxy) butyl-4-hydroxybenzoate (Compound 7f)

Yield = 0.48 g (92).

<Example 1>

(S) -2- (4-methoxy) butyl 4- (4'-dodecyloxybiphenyl-4-ylcarbonyloxy) benzoate (Compound 8a)

0.31 g (1.50 mmol) of 1,3-dicyclohexylcarbodiimide was dried at room temperature 4'-dodecyloxybiphenyl-4-carboxylic acid in 30 mL tetrahydrofuran, 0.23 g (0.82 mmol) of a compound 7a, 4 0.02 g (0.16 mmol) of -N, N-dimethylaminopyridine was added to the stirred mixture. The reaction was left to stir for 24 hours until TLC analysis showed no further reaction. The reaction mixture was diluted with 200 mL of dichloromethane and the insoluble precipitate of 1,3-dicyclohexylurea was removed by filtration through a pad of Hyflo-Supercell®. The filtrate was washed in the order of 50 mL of water, 2 × 50 mL of 10 (v / v) acetic acid, 50 mL of water, dried over MgSO ₄ , filtered and evaporated to give a colorless solid. Flash chromatography [micro mesh silica gel; 9: 1 hexane-ethyl acetate]; Purified by recrystallization (hexane × 4) and dried under vacuum (P ₂ O ₅ , 0.2 mbar, 40 ° C., 18 h). Yield = 0.16 g (11).

<Example 2>

(S) -2- (4-ethoxy) butyl 4- (4'-dodecyloxybiphenyl-4-ylcarbonyloxy) benzoate (Compound 8b)

Flash chromatography of the compound [micro mesh silica gel; 15 (v / v) ethyl acetate (x3) in hexanes] gave a colorless solid. It was recrystallized (ethanol × 5, acetonitrile × 2) and dried under vacuum (P ₂ O ₅ , 5.0 mbar, 40 ° C., 18 hours). Yield = 0.24 g (20).

<Example 3>

(S) -2- (4-butoxy) butyl 4- (4'-dodecyloxybiphenyl-4-ylcarbonyloxy) benzoate (Compound 8c)

Flash chromatography of the compound [micro mesh silica gel; 10 (v / v) ethyl acetate in hexane] afforded a colorless solid. It was recrystallized (ethanol × 5, hexane × 3) and dried under vacuum (P ₂ O ₅ , 1.0 mbar, 40 ° C., 8 hours). Yield = 0.29 g (51).

<Example 4>

(S) -2- (4-pentoxy) butyl 4- (4'-dodecyloxybiphenyl-4-ylcarbonyloxy) benzoate (Compound 8d)

Flash chromatography of the compound [micro mesh silica gel; 12 (v / v) ethyl acetate in hexane] afforded a colorless solid which was recrystallized (ethanol × 3, hexane × 3). Yield = 0.26 g (50).

Example 5

(S) -2- (4-dodecyloxy) butyl 4- (4'-dodecyloxybiphenyl-4-ylcarbonyloxy) benzoate (Compound 8e)

Flash chromatography of the compound [micro mesh silica gel; 13 (v / v) ethyl acetate in hexane, 9: 1 dichloromethane-hexane] to give a colorless solid. It was recrystallized (ethanol-ethyl acetate x 4). Yield = 0.88 g (47).

<Example 6>

(S) -2- (4-tetradecyloxy) butyl 4- (4'-dodecyloxybiphenyl-4-ylcarbonyloxy) benzoate (Compound 8f)

Flash chromatography of the compound [micro mesh silica gel; 13 (v / v) ethyl acetate in hexanes, 9: 1 dichloromethane-hexane] to give a colorless solid. This was recrystallized (ethanol-ethyl acetate x 4). Yield = 0.46 g (53).

<Example 7>

Scheme 2 summarizes the synthetic routes that can be used to obtain Formula 16. The following reaction conditions are similar to those described in Examples 1-6.

(R) -3-methylbenzyloxypentanoate (Compound 10)

A method similar to that described for compound 2 was used using compound 9, (-)-methyl (R) -3-hydroxyvalerate as starting material. The oil obtained after flash chromatography was further purified by distillation with cogel (1.0 mbar, 140 ° C.). Yield = 5.97 g (70).

(R) -3- (benzyloxy) pentan-1-ol (compound 11)

Compound 10 was synthesized using a method analogous to that described for compound 3 using starting material. The oil obtained after flash chromatography was further purified by distillation with cogel (1.0 mbar, 160 ° C.) Yield = 4.03 g (79).

(R) -3-benzyloxy-1-dodecyloxypentane (Compound 12)

Synthesis was carried out using the method described for compounds 4a to 4f. Yield = 2.56 g (80).

(R) -5-dodecyloxypentan-3-ol (compound 13)

Synthesis was carried out using the method described for compounds 5a to 5f. Yield = 1.82 g (96).

(R) -3- (5-dodecyloxy) pentyl 4-methoxycarbonyloxybenzoate (Compound 14)

Synthesis was carried out using the method described for compounds 6a to 6f. Yield = 0.65 g (33).

(R) -3- (5-dodecyloxy) pentyl 4-hydroxybenzoate (Compound 15)

Synthesis was carried out using the method described for compounds 7a to 7f. Yield = 0.54 g (67).

(R) -3- (5-dodecyloxy) pentyl 4- (4'-dodecyloxybiphenyl-4-carbonyloxy) benzoate (Compound 16)

Synthesis was carried out using the method described for compounds 8a to 8f. Yield = 0.49 g (41).

The phase transition temperatures (° C.) and enthalpy (shown in square brackets) of Examples 1 to 8 are listed in Table 1 below. Example 8 is a liquid crystal composition comprising each compound 8a to 8d in a mixture of 1: 1: 1: 1 weight / weight.

All phase transitions reported herein are enantiotopics, ie the phases are observed upon heating and cooling. Phase transition temperature relates to cooling.

Transition Temperature (℃) and Enthalpy of Examples 1-8 number Melting point Iso ^a S _A S _C S _{C A} S _X ^b K ^c 8a Example 1 69.4 [25.89] ^d 144.1 [4.19] 118.8 [0.17] - 44.5 [0.72] 32.9 [17.14] 8b Example 2 59.9 [26.97] 138.0 [4.11] 116.2 [0.32] - 41.8 [0.70] 35.1 [18.05] 8c Example 3 62.5 [31.73] 130.8 [4.84] 118.5 [-] ^c 118.4 [-] ^c 37.5 [23.07] - 8d Example 4 59.4 [30.99] 127.7 [4.63] 115.6 [-] ^c 115.2 [-] ^c 36.1 [22.76] - 8e Example 5 66.4 [51.46] 112.9 [4.30] 94.0 [0.11] 33.9 [31.25] - - 8f Example 6 66.1 [50.22] 111.3 [4.55] 87.5 [0.03] 54.5 [50.43] - - 16 Example 7 56.5 [70.79] 89.7 [4.67] 55.2 [0.01] 43.0 [62.97] - - Example 8 - 135.3 115.9 - 40.3 〈40 a: isotropic liquid b: undiscovered highly aligned smematic_I ^* c: crystalline solid d: enthalpy, unit: kJ / mol: Peak can be almost resolved by DSC, or enthalpy is not accurately measured (about 0.3-0.5 kJmol^-One)

The phase transition temperature was recorded using a differential scanning calorimeter (DSC) in combination with an optical microscope and a heating and cooling rate of 10 ° C./min. Differential scanning calorimetry was pre-marked using an indium standard (melting point: 156.60 ° C. and ΔH = 28.45 J / g).

Table 2 shows the switching characteristics of Examples 1 to 6 and Example 8.

Example number Tilt angle (degrees) Switching voltage (V) Switching time ¹ Ps ¹ (nC cm ^-2 ) On (ms) Off (ms) One 24.1 2.8 0.62 2.53 35 2 27.8 2.8 0.38 5.07 61 3 31.0 3.8 0.18 2.20 47 4 31.9 5.0 0.21 2.25 32 5 24.7 2.2 0.93 10.44 - 6 20.8 2.0 0.72 6.55 - 8 30.0 3.6 0.32 5.37 18.5 ^1, ADL Chandoni et.al. in J. Applied Physics, 1988, 27 (5) L729-L732

Schemes 3 and 4 below provide synthetic routes to the additional compounds mentioned in Example 9 below.

Route for (S) -2- (4-pentoxy) butyl 4-hydroxy-3-fluorobenzoate (compound 21 of Scheme 4)

Route for (S) -2- (4-pentoxy) butyl 4- (4'-dodecyloxy-monofluoro-substituted-biphenyl-4-carbonyloxy) benzoate

Example 9

A series of five mono fluoro substituted materials were synthesized and the structure and final steps are shown in Scheme 4. Using 1,3-N, N-dicyclohexyl carbodiimide (DCC) and 4-N, N-dimethylaminopyridine (DMAP), the material was suitably substituted biphenyl carboxylic acid (compounds 7a, 22- 25) was prepared by esterification with a chiral benzoate ester (Compound 7d or 21). Mono fluoro substituted carboxylic acids were prepared using a variety of methods including alkylation, palladium (0) catalyzed cross coupling, cyanation, hydrolysis and carboxylation reactions. Scheme 3 schematically shows the synthesis of (S) -2- (4-pentoxy) butyl 4-hydroxy-3-fluorobenzoate (21).

4-Benzyloxy-3-fluorobenzoic acid (18)

15.05 g of 1-bromo-4-benzyloxy-3-fluorobenzene (17) in 200 ml of dry tetrahydrofuran under a dry nitrogen atmosphere via 6.0 ml of butyllithium (10.0 M in hexane, about 54 mmol) through a syringe 53.6 mmol) was added dropwise to the cooled and stirred solution. During dropping the temperature did not exceed −70 ° C. and the colorless solution turned pale yellow while butyllithium was added. After the addition was complete, the reaction was allowed to stir for another 3 hours at −78 ° C. and poured into a slurry of 20 ml of solid carbon dioxide (about 50 g) and dry tetrahydrofuran. The resulting slurry was allowed to warm to room temperature with vigorous stirring and acidified by dropwise addition of concentrated hydrochloric acid. 200 ml of water was added, and the product was extracted using 3 * 100 ml of diethyl ether. Handemo ether layer was washed with brine, dried over MgSO ₄ , filtered and evaporated to yield an off-white solid. Recrystallized (hexane-ethyl acetate) and dried in vacuo (P ₂ O ₅ , 1.0 mbar, room temperature, 18 h). Yield = 7.02 g (53).

(S) -2- (4-pentoxy) butyl 4-benzyloxy-3-fluorobenzoate (19)

Prepared by the same method as the compound 6a-f. Flash chromatography [fine mesh silica gel; Hexane (initial), 3ethyl acetate-hexane (final)] to give a colorless liquid. Dry in vacuo (P ₂ O ₅ , 1.0 mbar, room temperature, 72 h). Yield = 2.68 g (57).

(S) -2- (4-pentoxy) butyl 4-hydroxy-3-fluorobenzoate (20)

2.62 g (7.0 mmol) of compound 19, 0.21 g of coal palladium hydroxide (water Pd 20), 30 ml of cyclohexene and 60 ml of ethanol were heated under reflux for 7 hours with stirring, after which no starting material remained in TLC. It was confirmed. The cooled reaction mixture was diluted with 200 mL of diethyl ether, filtered through a pad of Hyflo-Supercell, and the filtrate was evaporated under reduced pressure to give a light oil. Dry under vacuum (P 2 O 5, 1.0 mbar, room temperature, 24 hours). Yield = 1.89 g (90).

(S) -2- (4-pentoxy) butyl 4- (4'-dodecyloxy-3'-fluorobiphenyl-4-carbonyloxy) benzoate (26)

Flash chromatography [fine mesh silica gel; 12 ethyl acetate and fine mesh silica gel in hexane; 6: 4 dichloromethane-hexane] to give a colorless solid. Recrystallized (ethanol × 3) and dried in vacuo (P ₂ O ₅ , 0.5 mbar, 40 ° C., 18 h). Yield = 0.66 g (68).

(S) -2- (4-pentoxy) butyl 4- (4'-dodecyloxy-2-fluoro-biphenyl-4-carbonyloxy) benzoate (27)

Flash chromatography [fine mesh silica gel; 9 ethyl acetate and fine mesh silica gel in hexane; 8: 2 dichloromethane-hexane] twice to give a white solid. Recrystallized (ethanol × 4) and dried in vacuo (P ₂ O ₅ , 0.5 mbar, 40 ° C., 18 h). Yield = 0.59 g (59).

(S) -2- (4-pentoxy) butyl 4- (4'-dodecyloxy-2'-fluoro-biphenyl-4-carbonyloxy) benzoate (27)

Flash chromatography [fine mesh silica gel; 9 ethyl acetate and fine mesh silica gel in hexane; 7: 3 dichloromethane-hexane] twice to give a white solid. Recrystallized (ethanol × 4) and dried in vacuo (P ₂ O ₅ , 0.5 mbar, 40 ° C., 24 h). Yield = 0.59 g (59).

(S) -2- (4-pentoxy) butyl 4- (4'-dodecyloxy-3-fluoro-biphenyl-4-carbonyloxy) benzoate (29)

Flash chromatography [fine mesh silica gel; 10 ethyl acetate-hexane] was purified twice to give a white solid. Recrystallized (ethanol × 5) and dried in vacuo (P ₂ O ₅ , 0.5 mbar, 30 ° C., 18 h). Yield = 0.13 g (30).

(S) -2- (4-pentoxy) butyl 4- (4'-dodecyloxybiphenyl-4-carbonyloxy) -3-fluorobenzoate (30)

Flash chromatography [fine mesh silica gel; 8 ethyl acetate in hexane] to give a colorless solid which was recrystallized (ethanol × 3) and dried (P ₂ O ₅ , 1.0 mbar, 40 ° C., 18 h). Yield = 0.61 g (55).

Scheme 5 shows the route to the polyfluoro substituted liquid crystal material described in Example 10 below.

Route for (S) -2- (4-pentoxy) butyl 4- (4'-alkyloxy-polyfluoro-substituted-biphenyl-4-carbonyloxy) benzoate

<Example 10>

The following polyfluoro substituted materials were prepared in a similar manner as described for the mono fluoro substituted materials (26-30) outlined in Scheme 5. Various mono fluoro and difluoro substituted biphenyl carboxylic acids (22 and 31) were prepared via various alkylation, palladium (0) catalyzed cross coupling, cyanation, acid hydrolysis and carboxylation reactions.

(S) -2- (4-pentoxy) butyl 4- (2 ', 3'-difluoro-4'-octyloxybiphenyl-4-carbonyloxy) benzoate (32)

Flash chromatography [fine mesh silica gel; 10 ethyl acetate and fine mesh silica gel in hexanes; 6: 4 dichloromethane-hexane and fine mesh silica gel; 8: 2 dichloromethane-hexane] to give a colorless solid, which was filtered through a Millipore membrane filter, evaporated and dried in vacuo (P ₂ O ₅ , 1.0 mbar, room temperature, 45 h). Yield = 0.46 g (52).

(S) -2- (4-pentoxy) butyl 4- (4'-dodecyloxy-3'-fluorobiphenyl-4-carbonyloxy) -3-fluorobenzoate (33)

Flash chromatography [fine mesh silica gel; 8 ethyl acetate-hexane and fine mesh silica gel; 1: 1 dichloromethane-hexane] twice to give a colorless solid, which was recrystallized (methanol-ethyl acetate × 6) and dried in vacuo (P ₂ O ₅ , 1.0 mbar, 40 ° C., 48 h). Yield = 0.77 g (66).

(S) -2- (4-pentoxy) butyl 4- (2 ', 3'-difluoro-4'-octyloxybiphenyl-4-carbonyloxy) -3-fluoro-benzoate (34 )

Flash chromatography [fine mesh silica gel; 10 ethyl acetate in hexane] gave a colorless gel. It was redissolved in dichloromethane, passed through a Millipore filter, concentrated and dried in vacuo (P ₂ O ₅ , 1.0 mbar, 50 ° C., 18 h). Yield = 0.74 g (57).

Scheme 6 was used to generate the compound described in Example 11 below.

Route to chiral terphenyl substance

<Example 11>

A chiral terphenyl liquid crystal material was prepared using a palladium (0) catalyzed cross coupling method under anhydrous and biphasic Suzuki conditions. Anhydrous coupling was performed using aryltriplate and aryl boric acid, and triethylamine base in 1,2-dimethoxyethane, and Suzuki coupling was carried out using arylbromide and arylboric acid and sodium carbonate as base (above) See Scheme 6).

4 '-(4-octyloxyphenyl) phenylboric acid (36)

Butyllithium 2.0 cm ³ (about 20 mmol, 10.0 M solution in hexane) at −78 ° C. under dry N ₂ was injected via syringe into 4-bromo-4′-octyloxybiphenyl (35) in 150 ml of dry tetrahydrofuran. 6.05 g (16.8 mmol) was added dropwise to the stirred mixture. The reaction was left to stir at −78 ° C. for an additional 4 hours, and 3.58 g (34.5 mmol) of trimethyl borate in 20 ml of dry tetrahydrofuran were added dropwise to prevent heat generation. The mixture was stirred for an additional 1.5 h at -78 ° C and then allowed to warm to rt overnight. 50 ml of 10 (v / v) hydrochloric acid was added dropwise to hydrolyze the boric acid ester. The mixture was stirred for a further 0.5 h, then poured 200 ml of water and extracted with 3 × 70 ml of diethyl ether. Handemo ether ether extracts were dried over MgSO ₄ , filtered and evaporated to give a waxy colorless solid which was dried under vacuum (P ₂ O ₅ , 10 mbar, room temperature, 72 h).

(S) -2- (4-pentoxy) butyl 4- (trifluoromethylsulfonyloxy) benzoate (37)

3.35 g (11.9 mmol) of trifluoromethylsulfonic anhydride were added dropwise to a stirred and cooled mixture of 2.38 g (8.5 mmol) of compound 7d in 20 mL of dry pyridine under dry nitrogen. After completion of the dropwise addition, the reaction was allowed to warm to room temperature overnight. The reaction was poured into 200 mL of water and the product was extracted using 5 x 50 mL of diethyl ether. HANDemo silver ether phase extract was washed with 50 ml of water, 2 × 50 ml of 10 hydrochloric acid, 50 ml of water, 50 ml of saturated sodium chloride and 50 ml of water, dried over MgSO ₄ , filtered under vacuum and evaporated to give a pale yellow liquid. . Flash chromatography [fine mesh silica gel; 10 ethyl acetate in hexane] gave a colorless liquid. Dry under vacuum (P ₂ O ₅ , 0.2 mbar, room temperature, 18 h). Yield = 3.02 g (84).

4-Bromo-1-((S) -1-methyl-3-pentoxypropoxy) benzene (39)

0.51 g (2.93 mmol) of (R) -4-pentoxybutan-3-ol (5d), 0.51 g (1.94 mmol) of triphenylphosphine in 10 mL of tetrahydrofuran dried at room temperature under dry N ₂ To a solution of 0.35 g (2.01 mmol) of diethyl azodicarboxylate and 0.34 g (1.96 mmol) of 4-bromophenol (38) in 5 mL of furan was added dropwise. The reaction was stirred for an additional 48 hours at room temperature, then diluted with 100 mL of diethyl ether and filtered through a Hyflo-supercell pad. The filtrate was washed with 50 mL of water, dried over MgSO ₄ , filtered under vacuum and evaporated to give a colorless oil. Flash chromatography [fine mesh silica gel; Dichloromethane] to give a colorless oil and dried under vacuum (P ₂ O ₅ , 10 mbar, room temperature, 18 h). Yield = 0.39 g (62).

(S) -2- (4 ''-octyloxyterphenyl-4-carbonyloxy) -1-pentoxybutane (40)

1.37 g (3.6 mmol) of compound 37, 1.28 g (3.9 mmol) of compound 36, 0.18 g (0.16 mmol) of palladium (0) tetrakis (triphenylphosphine), 0.47 g (11.1 mmol) of lithium chloride, triethylamine 30 ML and 30 mL of 1,2-dimethoxyethane were heated under mild reflux for 5 hours under dry N ₂ (TLC analysis showed no starting material remaining). The reaction was diluted with 150 mL of dichloromethane, filtered through a pad of Hyflo-Supercell, the filtrate was washed with 2 x 50 mL of water, 50 mL of brine, dried over MgSO ₄ , filtered and evaporated to give a pale yellow solid. Got it. Flash chromatography [fine mesh silica gel; 10 ethyl acetate and fine mesh silica gel in hexanes; 1: 1 dichloromethane-hexane] to give a colorless solid. Recrystallized (ethanol-ethyl acetate × 2) and dried under vacuum (P ₂ O ₅ , 10 mbar, 50 ° C., 8 hours). Yield = 0.34 g (17).

(S) -2- (4 ''-octylterphenyl-4-oxy) -1-pentoxybutane (41)

0.47 g (1.44 mmol) of compound (36), 0.36 g (1.14 mmol) of compound (39), 0.04 g (0.03 mmol) of palladium (0) tetrakis (triphenylphosphine), 8 mL of 2M sodium carbonate solution and 1,2 8 ml of dimethoxyethane was heated under gentle reflux with stirring for 5 h under dry N ₂ (TLC analysis did not show residual arylbromide). The reaction was poured into 100 mL of water and the product was extracted using 3 x 70 mL of diethyl ether. HANDemo silver ether extract was washed with 50 ml brine, dried over MgSO ₄ , filtered and evaporated to give a dark solid which was passed through a short silica gel column with dichloromethane to remove the base material. Purification of the pale solid by flash chromatography [Fine mesh silica gel; 1: 1 dichloromethane-hexane, followed by fine mesh silica gel; 9: 1 dichloromethane-hexane] to give a colorless solid. Recrystallized (toluene × 3) and dried under vacuum (P ₂ O ₅ , 10 mbar, 50 ° C., 8 hours). Yield = 0.16 g (27).

In order to confirm the optical purity of the desired compounds and intermediates, two methods, (1) the use of NMR and chiral transfer reagent methods, and (2) derivatization that can be quantified by analytical devices (ie, NMR, GC or HPLC) The formation of diastereo isomer mixtures by means of was used.

Method (1)-Direct NMR and Chiral Transfer Reagent Methods

Same procedure as described in the synthesis of (S) -enantiomer (Compound 8d) as described in Scheme 2, except that a racemate (R, S) -sample of methyl-3-hydroxybutyrate was used. The racemic variant of (S) -2- (4-pentoxy) butyl 4- (4'-dodecyloxybiphenyl-4-carbonyloxy) benzoate (42) was prepared using the reaction of. This material was used to determine the optical purity of (S) -enantiomer using ¹ H NMR and chiral shift reagent Europium Tris (D-3-fluoroacetylcamphorate). However, increasing the shift reagent to the NMR reagent resulted in a line width of the aromatic hydrogen signal.

Method (2)-chemical derivatization with esters of Mosher

Formation of ester derivatives of mosher

(R) -Mosher ester of (S) -2- (4-pentoxy) butyl 4-hydroxybenzoate (44)

100 mg of (R)-(-)-α-methoxy- (trifluoromethyl) phenylacetylchloride was injected via syringe / diaphragm into (S) -2- (4-pentoxy) butyl 4-hydroxybenzoate ( 7d) injected into a vial containing 0.06 g and 0.5 ml of dry triethylamine. The yellow solution immediately became turbid and 'gelled' as the hydrochloride precipitated. The reaction was warmed to 60 ° C. for another 2 hours and quenched with 1 ml of water and 1 ml of 10 (v / v) hydrochloric acid. The product was extracted using 4 x 0.5 mL of dichloromethane. The organic solution was concentrated and then purified by column chromatography [silica gel; dichloromethane] and the product (Rf = 0.21 (CH ₂ Cl ₂ )) was collected from 16 fractions, concentrated in vacuo and dried (P ₂ O). ₅ , 10 mbar, room temperature, 3 hours).

Coupling was confirmed by HH Cozy (COSY) spectroscopy.

The synthesis of (R, S) -2- (4-pentoxy) butyl 4-hydroxybenzoate (43, compound 42) was analogous to the method for preparing a sample of the ester mixture of racemic mosher (45). Prepared for) and its NMR spectrum was the same as described for compound 44.

Under the assumption that compound 44 is optically pure, the main product will be (R)-, (S) -diastereo isomer, in which a small amount of (R), (R) -diastereomer is also present. As such Compound 45 can be expected to include the same amount of (R)-, (R) -Mosher ester diastereo isomer and (R)-, (S) -Mosher ester diastereo isomer. Analysis of these substances will confirm this. Initially, the optical purity of the two materials was measured using ¹⁹ F NMR, but no resolution of the CF ₃ signal (about 72 ppm) was observed with respect to 'racemate' or 'enantiomer' (compounds 44 and 45 each). Similarly, GC failed to separate different diastereo isomers due to the low volatility of the compound under GC injection conditions (220-280 ° C.). However, HPLC of a sample on a silica gel column using a 97: 3 hexanes: 2-propanol solvent mixture showed that one diastereo isomer (ie, (S) -2- (4-) has a retention time of 7.43 minutes. Pentoxy) butyl 4-hydroxybenzoate (7d) and all final liquid crystal materials are optically pure). Compound 45 was isolated with (R), (R) and (R) and (S) diastereo isomers with retention times of 6.97 and 7.33 minutes, respectively.

The transition temperatures and phase behaviors of compounds 26-30, 32-34 and 40-42 were measured using a combination of optical microscopy and differential scanning calorimetry, and the results are listed in Table 3 below.

Liquid crystal phase transition temperature of various materials compound Transition temperature (° C) and enthalpy [kJ / mol] ² Melting point Iso S _A S _C ˚ S _C ˚ _A K 26 51.8 [44.01] 109.5 [4.84] 100.7 [0.46] 100.6 [-] ^b 24.40 [37.17] 27 42.3 [40.31] 91.0 [4.95] 69.6 [0.11] -9.7 [17.41] 28 44.7 [41.97] 90.1 [5.31] 58.8 [0.03] -20.7 [8.84] 29 31.9 [30.76] 114.3 [5.02] 99.1 [0.25] 99.1 [-] ^b -8.7 [14.56] 30 44.9 [25.63] 100.9 [4.73] 83.7 [0.13] -26.3 [20.88] 32 26.2 [15.96] 102.9 [4.49] <-30.0 [-] ^c 33 40.1 79.9 [42.68] 71.2 [4.09] [0.17] <-20.0 [-] ^c 34 33.7 [26.36] 65.9 [3.64] <-50.0 [-] ^c 40 96.0 and 131.9 ^d [9.53] [16.43] 154.6 [5.73] 137.5 [0.49] 129.2 [15.80] 41 87.8 and 135.6 ^d [12.94] [20.72] 138.4 [8.31] 132.0 [8.21] 42 (R, S) ^c 58.5 [35.70] 128.5 [5.20] 116.6 [0.49] 32.0 [22.29] a: obtained from DSC scan at a heating and cooling rate of 10 degrees / min. b: peak directly obtained by DSC. However, the enthalpy is difficult to measure accurately c: no crystallization during the experimental cycle d: material exhibits two crystalline forms e: racemic material shows S _C phase, not S _C ˚ phase

Electro-optical results

ITO coated cells arranged in parallel in parallel with a thickness of 2-3 μm were filled with each material of the isotropic phase and left to cool slowly to room temperature. The electrode was attached to ITO and the cell was placed between crossed polarizers. The cone angle θ, the spontaneous polarization P _S, and the on (τ on) and off (τ off) reaction times for voltage at several temperatures were measured. [Tau] was obtained by switching between 90 bright states in the dark (off) state. Defined as being time (ie, T ₀ -T ₉₀ ), τ off is obtained by switching time between the brightest (on) state and the dark state of 10 (ie, T ₁₀₀ -T ₁₀ ).

The melting points of (S) -2- (alkoxy) butyl 4- (4'-dodecyloxybiphenyl-4-ylcarbonyloxy) benzoate (8a to 8f) are all room temperature or higher (59.4-69.4 ° C, Table 1 above). Therefore, the melting point should be reduced by using it as a mixture with other materials. Appropriate properties (cone angle, switching speed and spontaneous polarization) are listed in Table 4 below.

Properties of (S) -2- (alkoxy) butyl 4- (4'-dodecyloxybiphenyl-4-ylcarbonyloxy) benzoate (8a to 8f) number n θ (˚) τ temperature ＠ 70 ℃ (ms) τ temperature ＠ 70 ℃ (ms) P _S ＠ 70 ° C (nCcm ^-2 ) 8a One ± 29.5 0.62 2.53 50 8b 2 ± 30.2 0.38 5.07 74 8c 4 ± 32.5 0.18 2.20 71 8d 5 ± 34.5 0.21 2.25 102 8e 12 ± 24.7 0.93 10.44 - 8f 14 ± 20.8 0.72 6.55 -

The dependence of the cone angle on the temperatures of compounds 8a-8d and compounds 8e and 8f is shown in FIGS. 1 and 2, respectively. For most device applications, maximum brightness is obtained when the cone angle is 45 °, i.e. the darkest state (typically 0 V state) is obtained when the director is arranged with one of the polarizers, and the director has each polarization The brightest state was obtained when arranged at 45 ° with respect to wood. Ideally, the cone angle should be as close to 45 ° as possible to achieve optimum efficiency. Achievable cone angles of 30 [deg.] Correspond to the sin ² ( ² [theta]) relationship, for example correspond to a luminance of 0.7 and cone angles of 35 [deg.] Correspond to a luminance of about 0.9. However, other device geometries can be used when the maximum cone angle is less than 45 °.

The phases of these materials are inadequate, but the cone angles of compounds 8a-d range from about 30-35 °, providing the possibility of 0.9 transmission. All the τ temperatures were below the appropriate ms for most devices. However, τ off was quite long. However, these measurements were taken at 70 ° C. and due to the viscosity they were quite long at room temperature.

(S) -2- (4-pentoxy) butyl 4- (4'-dodecyloxy-monofluoro-biphenyl-4-ylcarbonyloxy) benzoate (26-30)

To lower the melting point and phase transition temperature, a fluorine atom was substituted at each of the a, b, c or d positions of the biphenyl core of formula 113 below.

Phase transitions are shown in Table 3. The addition of fluorine atoms anywhere in the core had the effect of lowering the melting point and phase transition. However, the values are above room temperature but are candidates for use as components of the mixture. The measurement was performed at 40 ° C. below the melting point of the compound except for No. 29. The material was supercooled to facilitate measurement at temperatures below the melting point. The general trend is that the cone angle of the compound where F is inside the ring (b or c position) is much lower than the compound where F is outside the ring (a or d position). To determine the maximum cone angle so that the temperature difference does not reach 40 ° C. and also to investigate the actual tilt angle with temperature change, θ was measured over the entire tilted phase range. This reduced θ to about ± 31 ° for compounds 26 and 120 and for 27 and 101 as listed and plotted below. However, when F was in the inner position of the ring, the cone angle tended to be quite small. Electro-optical measurements are shown in Table 5 below.

(S) -2- (4-pentoxy) butyl 4- (4'-dodecyloxy-monofluoro-substituted-biphenyl-4-ylcarbonyloxy) benzoate (26-29) number a b c d θ (˚) τ temperature 40 ° C (ms) τ Offset 40 ° C (ms) S _C ° → K (℃) P _S ＠ 30 ° C (nCcm ^-2 ) 26 F H H H 34.5 0.70 3.2 24.2 85 27 H H F H 19.5 0.50 9.0 -9.7 57 28 H F H H 16.2 0.30 8.0 -20.9 28 29 H H H F 30.2 0.18 1.0 -8.7 68

3 shows the dependence of tilt on temperature for four different fluoro substitution patterns. The maximum cone angles and appropriate temperature ranges for compounds 26 to 29 are listed in Table 6 below.

Cone Angle and Temperature Range of Compounds 26-29 Compound d F Temperature Max cone angle 26 a 50-55 ℃ ± 30.7˚ 27 b 45 ℃ ± 18.8˚ 28 c 45 ℃ ± 11.7˚ 29 d 35-50 ℃ ± 30.8˚

The phase of the material is not ideal, but the cone angles (about ± 30 °) of compounds 26 and 29 provided the possibility of transmission of 0.75. For the non-fluorinated series, τ ions were all below the appropriate ms for most devices, and τ off was quite long. However, these measurements were made at 40 ° C. and due to the viscosity they were quite long at room temperature.

Phase range and reaction time were improved for the non-fluorinated series, and in the case of mixtures, the possibilities were improved as components.

(S) -2- (pentoxy) butyl 4- (4'-alkoxy-polyfluoro-substituted-biphenyl-4-ylcarbonyloxy) benzoate and 3-fluoro-benzoate (32, 33 And 34)

To further reduce the phase transition, two or three fluorine atoms were substituted for the ring of the core at the position shown in the above formula. Phase transitions are listed in Table 3. Compounds 32 and 34, having a and b, and substituents at positions a, b, and c, respectively, lost a completely tilted phase (ie, only had S _A ). Comparison of compound 26 and compound 33 showed that the addition of F to the e position of the third ring reduced the melting point by about 12 ° C. and reduced the I-S _A transition by about 40 °. The results measured at 50 ° C. are provided in Table 7 below.

(S) -2- (pentoxy) butyl 4- (4'-dodecyloxy-3'-fluoro-4-carbonyloxy) -3-fluoro-benzoate (33) number a b c d θ (˚) τ temperature (ms) τ off (ms) S _C ° → K (℃) P _S (nCcm ^-2 ) 33 F H H F ± 30.2 5.8 11.0 <-20.0 58

The maximum θ was obtained at 1.6 V. The measurement of θ vs. temperature was recorded. Only tilt angle 0 increased very slightly from 45 ° C. to ± 30.5 ° and is shown in FIG. 4.

In the original series of fluoro unsubstituted materials (compounds 8a-8f), mixing of compounds of different chain lengths (8e (n = 12) and 8d (n = 5) 1: 1) yielded mixtures with similar melting points. The S _A -Iso and S _C *-S _A transitions were nearly intermediate between the two components and the crystallization point was lowered only in small amounts. Mixing of compound 8d (n = 5) and compound 29 (d = F, n = 5) yielded a mixture with intermediate properties between the two components. Mixing of the di / tri fluoro substituted series produced a mixture with the appropriate switching angles that could be used for room temperature operation and devices. Mixtures of compounds 33, 32 and 34 (75:10:15 ratio) gave the following phases as characterized by optical microscopy and DSC (see Table 8 below).

Transition Temperature and Enthalpy of 75:10:15 Mixture of Compounds 33. 32 and 34 number Melting point Iso S _A S _c * K 33:32:34 (75:10:15) 16.6 ^a [33.15] ^b 79.0 [5.81] 57.5 [0.034] a measured by leaving the material at room temperature overnight and then cooled at −50 ° C. for 3 hours. b Enthalpy, unit kJ / mol

The cone angle versus voltage characteristics of the three-component mixture were recorded (FIG. 5) and a maximum cone angle of ± 27.5 ° was obtained at about 3.6 V.

In summary, the mixing of di / trifluoro substituted compounds 33, 32 and 34 in a 75:10:15 ratio provides room temperature switching with a cone angle of ± 27.5 ° (corresponding to a maximum theoretical transmission of 0.67). A mixture was produced.

6 shows the structure of a typical cell in a liquid crystal device comprising an active matrix array. A pair of permeable substrates (glass or polymer plates) 2 and 4 were arranged almost parallel to the gap 6 between them. Plates 2 and 4 were placed between crossed polarizers (not shown) arranged such that the maximum dark state of the device was obtained at an applied voltage of 0 volts. Opposing surfaces 2a and 4a of each transmissive substrate 2 and 4 were provided with a transmissive electrode 8, respectively, and an array layer (e.g., organic or inorganic thin film) 9 was provided for each It was provided over the electrode 8. The interval 6 contained the liquid crystal composition according to the present invention.

An almost constant voltage was applied across the liquid crystal material during each subframe of the dipole switching waveform shown in FIGS. 7A and 7B to implement the addressing scheme for the device. The application of this voltage can be accomplished in two different ways. In the first embodiment shown in FIG. 8, the square active matrix array 10 of pixels comprises a vertical electrode addressed by the data driver 12 and a horizontal electrode addressed by the scan driver 14, each pixel having The connected active circuit 16 is connected to the scan electrode 20 by its gate and parallel to the polysilicon thin film filter effect transistor 18, the capacitor 26, connected by its drain to the data electrode 22. A fixed storage capacitor 24 connected to a source of power. When the electrode 20 receives a scan pulse from the scan driver 14, the transistor 18 is turned on so that the voltage on the data electrode 22 is applied by the data driver 12 to charge the storage capacitor 24. When the scan pulse is removed from the scan electrode 20, the transistor 18 is turned off to separate the storage capacitor 24 from the data electrode 22 so that the light transmission of the pixel is recharged for the next frame. Corresponds to the voltage across. Since the polarization, which is a spontaneous spontaneous liquid crystal method, is high, it is necessary to apply a large amount of charge to the pixel, and therefore a large storage capacitor 24 is necessary to perform charge transfer at an almost constant voltage. However, the charge must be moved within the scan line period, which requires a significant peak current to flow and consumes significant power. Moreover, large storage capacitors adversely affect the aperture ratio of the display.

A variant active circuit 16 ′ for use in the device of the present invention is shown in FIG. 9, and in addition to the components already mentioned, the buffer amplifier 28 has a very high input impedance and a relatively low output impedance, so that the transistor 18 Is turned off and the output of the amplifier 28 follows the voltage across the storage capacitor, while the current supplied to the input of the amplifier 28 is negligible so that the discharge of the storage capacitor 24 is much slower than in the previous circuit arrangement. Thus, storage capacitor 24 may be a relatively small capacitor that can easily be charged below a predetermined voltage when transistor 18 is on. The pixel connected to the output of the amplifier 28 receives a constant voltage equal to the voltage of the storage capacitor 24, and since the electric charge is supplied at a rate at which the liquid crystal material is switched, the circuit consumes less power than the active circuit described above. The buffer amplifier can also perform the necessary subframe inversion in the addressing scheme to achieve repeatable gray levels.

According to the method of the present invention, compounds and compositions exhibiting a wide range of antiferroelectric S _A phases, low switching times, voltages and polarization coefficients, and liquid crystal devices including the same can be obtained.

Claims (44)

A pair of substrates, a layer of antiferroelectric liquid crystal material disposed between the substrates, and voltage application means for applying a voltage across the layer to control the formation of an antiferroelectric phase in the layer, the antiferroelectric material comprising Liquid crystal device comprising the compound of formula 106. <Formula 106> Where a is 1 to 16, b is 1 or 2, c is 1 to 14, n, p and r are each independently 0 or 1, Rings A and B are each independently selected from the group consisting of cyclohexyl, unsubstituted phenyl, mono-fluorophenyl, difluorophenyl, dioxanyl, pyrimidyl and pyridinyl, X is H or F, Y and Z are each independently selected from the group consisting of CC, C≡C, CO ₂ , O ₂ C and O, (*) Represents an asymmetric carbon atom. The device of claim 1, wherein c is 1 to 11 in the compound of Formula 106. The device of claim 2, wherein c is 1 to 5 in the compound of Formula 106. 4. Device according to any one of the preceding claims, wherein n is 1 in the compound of formula 106. The device of claim 4, wherein ring A in the compound of Formula 106 is unsubstituted phenyl or monofluorophenyl. 4. Device according to any one of claims 1 to 3, wherein in the compound of formula 106 ring B is unsubstituted phenyl or monofluorophenyl. 4. The device of claim 1, wherein X in the compound of Formula 106 is F. 5. 4. The device of claim 1, wherein Y is CO ₂ and p is 1 in the compound of Formula 106. 5. 4. The device of claim 1, wherein Z is CO ₂ and r is 1 in the compound of Formula 106. 5. 4. The compound of claim 1, wherein in the compound of formula 106 a is 12, b is 1, c is 1 to 5, n, p and r are each 1, and rings A and B Are each unsubstituted phenyl or monofluorophenyl, and Y and Z are each CO ₂ . The device of claim 1, wherein the layer is capable of switching from a dark state to a transmissive state within a time of less than 0.65 ms. The device of claim 11, wherein the layer is capable of switching from a dark state to a transmissive state within a time of less than 0.4 ms. The device of claim 1, wherein the layer can switch from a transmissive state to a dark state within a time of less than 5.1 ms. The device of claim 13, wherein the layer is capable of switching from a transmissive state to a dark state within a time of less than 2.6 ms. The device of claim 11, wherein the layer can exhibit a change in transmission state at a threshold voltage of less than 5V. The device of claim 15, wherein the threshold voltage is less than 4V. 17. A device in accordance with claim 15 or 16 capable of exhibiting nonlinear transmission behavior in response to a change in voltage near a threshold voltage. The device of claim 1, wherein the compound of Formula 106 has a spontaneous polarization coefficient (P _S ) of less than 65 nC / cm 2. The device of claim 18, wherein the compound of Formula 106 has a spontaneous polarization coefficient (P _S ) of less than 35 nC / cm 2. A device according to any one of claims 1 to 3, wherein the compound of formula 106 can exhibit antiferroelectric behavior characterized by the presence of a liquid crystal chiral smectic C _A (S _A ) phase. The device of claim 20, wherein the compound of Formula 106 has a S _A phase temperature range of greater than 70 ° C. 21. The device of claim 20, wherein the compound of Formula 106 may exist as an antiferroelectric S _A phase below 45 ° C. 24. The device of claim 20, wherein the compound of Formula 106 can exhibit a critical nonferroelectric behavior. A compound of formula 106 as defined in claim 1, representing (or) a chiral smectic C _A (S _A ) phase and at least one of X, ring A and ring B having a fluorine atom. The compound of claim 24, wherein c is 1-11. The compound of claim 25, wherein c is 1-5. 27. The compound of any of claims 24-26, wherein n is 1. The compound of claim 27, wherein ring A is unsubstituted phenyl. The compound of claim 27, wherein ring A is fluoro substituted phenyl. 30. The compound of any of claims 24-29, wherein ring B is unsubstituted phenyl. 30. The compound of any of claims 24-29, wherein ring B is fluoro substituted phenyl. 27. The compound of any of claims 24-26, wherein X is fluorine. 27. The compound of any of claims 24-26, wherein Y is CO ₂ and p is 1. 27. The compound of any one of claims 24-26, wherein Z is CO ₂ and r is 1. 35. A semiferroelectric liquid crystal composition comprising at least one compound according to any one of claims 24 to 34. (i) converting the compound of formula 107a to the compound of formula 107b, (ii) forming an ester bond between the compound of Formula 107b and the compound of Formula 107c to obtain a compound of Formula 107d, (iii) converting B of the compound of formula 107d to H, (iv) stereoselective for preparing a compound of formula 107 comprising a sequential step of forming an ester bond between the unblocked compound of step (iii) and a compound of formula 107e Way. <Formula 107> <Formula 107a> <Formula 107b> <Formula 107c> <Formula 107d> <Formula 107e> Where a is 1 to 16, b is 1 or 2, c is 1 to 14, n is 0 or 1, Rings A and B are each independently selected from the group consisting of cyclohexyl, unsubstituted phenyl, monofluorophenyl, difluorophenyl, dioxanyl, pyrimidyl and pyridinyl, R is C _1-6 alkyl, X is H or F, B is a breaker. 37. The stereoselective method of claim 36, wherein B is selected from the group consisting of methoxycarbonyl, benzyl and tetrahydropyranyl. A method of preparing a compound of Formula 107 comprising reacting a compound of Formula 108 with a compound of Formula 109: <Formula 107> <Formula 108> <Formula 109> Wherein ring A, ring B, a, b, c, n and X are as defined in claim 36. A method for preparing a compound of Formula 106a comprising reacting a compound of Formula 110 with a compound of Formula 111 or 112: <Formula 106a> <Formula 110> <Formula 111> <Formula 112> Where a is 1 to 16, b is 1 or 2, c is 1 to 14, n is 0 or 1, Rings A and B are each independently selected from the group consisting of cyclohexyl, unsubstituted phenyl, monofluorophenyl, difluorophenyl, dioxanyl, pyrimidyl and pyridinyl, X is H or F, Z is CO ₂ or O, (*) Represents an asymmetric carbon atom, Tf represents trifluoromethylsulfonyl. The device of claim 10, wherein the layer can be switched from a dark state to a transmissive state within a time less than 0.65 ms. The device of claim 10, wherein the layer can be switched from a transmissive state to a dark state within a time of less than 5.1 ms. The device of claim 10, wherein the compound of Formula 106 has a spontaneous polarization coefficient (P _S ) of less than 65 nC / cm 2. The device of claim 10, wherein the compound of Formula 106 has a spontaneous polarization coefficient (P _S ) of less than 35 nC / cm 2. The device of claim 10, wherein the compound of Formula 106 can exhibit antiferroelectric behavior characterized by the presence of a liquid crystal chiral smectic C _A (S _A ) phase.