JPS6084386A - Liquid crystal compound - Google Patents

Abstract

PURPOSE:To provide a chiral smectic liquid crystal compd. consisting of a specified biphenyl ester compd. and useful for electric optical elements employing a ferroelectric liquid crystal. CONSTITUTION:The liquid crystal compd. consists of optically active 3-chloro-4- n-alkoxyphenyl 4'-(2-methylbutyl)biphenyl-4-carboxylate of formula I (where n is 1-12: * is an asymetric carbon atom). A biphenyl ester compd. of formula II is known to have a phase transfer temp. of about 80 deg.C and develops a chiral smectic phase within a range of about 10 deg.C. The compd. of formula I is obtained by substituting H at position 3 of a benzene ring on a phenol side of a compd. of formula II, with Cl and it develops a chiral smectic phase at a lower temp. and within a wider temp. range. When used for an element, it improves spontaneous polarization which has an important effect upon properties of the element.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to novel ferroelectric liquid crystal materials useful for electro-optical elements that utilize the response of ferroelectric smectic liquid crystals to electric fields, and liquid crystals containing them. The present invention relates to a composition and an electro-optical device.

[Prior art]

Liquid crystals have been applied as various electro-optical elements. % compact and energy efficient, it is used as a voltage-driven optical pulp to display clocks and calculators. The liquid crystal elements currently in practical use are mainly
It is based on the dielectric alignment effect of nematic liquid crystal and cholesteric liquid crystal, in this case, due to dielectric anisotropy,
The long axis direction of the average molecule is oriented in a specific direction by the applied electric field.The dielectric coupling force with the applied electric field due to this mechanism is quite weak, so the electro-optics of these devices The response time is too slow for many potential applications.

Liquid crystal elements have excellent characteristics such as low voltage and low power consumption, good compatibility with [C], and compactness, but they are especially promising for application to display elements with a large number of pixels. However, responsiveness and nonlinearity are still insufficient. Therefore, M
On the other hand, research and development on OS panels and TPT panels is becoming more active.

Under these circumstances, C1a, rk 3 (σs Pat, 4
367924) eliminates the drawbacks of such liquid crystal elements.

We have devised a liquid crystal device based on a new display principle using a smectic phase. This will be explained briefly below in Figure 1.
is a schematic diagram of the smectic '* or H phase.A liquid crystal consists of each molecular layer 1, and within each layer, the average direction of the long axis of the molecules is angularly parallel to the direction perpendicular to the layer. , tilted high. Meyer 5 is Le Journal
de Physiqu, e Vol, 36 (Ma
rcb 1975PPL-69to-L-y 1) "
In a paper titled ``Ferroelectric Liquid Crystals'', it is shown that smectic C or H liquid crystals, which are composed of optically active molecules, generally have an electric dipole density p, indicating that they are ferroelectric. This dipole density T is perpendicular to the molecular inclination direction R and parallel to the smectic layer plane. What they showed is also applicable to smectic H-phases, but the H-phase has a greater viscosity for rotation about an axis perpendicular to the layer. The presence of electric dipoles in these chiral smectics provides a stronger binding force to the electric field than in dielectric anisotropy. Furthermore, since this binding force is polar in the sense that the preferred direction of the ama is parallel to the seedling, reversing the direction of the applied electric field will reverse the direction of f. In other words, by reversing the electric field, as shown in Figure 2,
By moving the molecules along the cone, their direction can be controlled.

By detecting the change in the average long axis direction of the molecules using two polarizing plates, it can be used as an electro-optical element.

Electro-optical elements that utilize the response of this smectic C* phase or H phase to an electric field are TN type because the coupling force between the spontaneous polarization and the electric field is 3 to 4 orders of magnitude larger than the coupling force due to dielectric anisotropy. Compared to liquid crystal elements, it has excellent high-speed response, and by selecting appropriate alignment control, it can have memory properties, making it useful for high-speed optical shutters and displays with a high amount of displayed information. is expected to be applied.

By the way, various chiral smectic liquid crystal materials having ferroelectricity have been synthesized and studied. The first ferroelectric liquid crystals synthesized were general P O, B
It is said to be AMBO.

P-der, yloxybenzilident -P
'-amino ・2-methy', -cynna
matθ, and various liquid crystals of this series have been synthesized as research objects of ferroelectric liquid crystals in the form of the following structural formula.

(Here, x: H, cl, aNy; OA', O,
However, since this series of liquid crystals exhibits a chiral smectic phase at relatively high temperatures, they have problems such as not being able to be used at room temperature, and being thick and having poor stability. It is expressed as a general formula. A hydroxyl group is introduced into one benzene ring,
A type of chiral, X-tactic liquid crystal compound having intramolecular hydrogen bonds is B, T, Qetrovekii.
3 (FerroellOctrics 24 (19
80) 309) and A, Hallsb73 CMo
1. Cryet Liq 0ry8t'LsttI
4r 82 (1982) ISl),
It is attracting attention as a compound that exhibits 8cζ in a wide temperature range including room temperature. Because it has intramolecular hydrogen-bonded gold, it has superior stability compared to thick liquid crystals, but there is still a problem with stability with organic seals that are formed into films.
There are other azoxy-based liquid crystal materials that cannot be put to practical use immediately, such as those described by P. Keller [Amn Phye, 3].
(1q 7 a ) 13 q ], but the temperature range is insufficient and the compound is dark yellow, which poses practical problems.

Under these circumstances, ester-based liquid crystal, which has a proven track record of stability as a TN-type liquid crystal material, is a promising material. In known literature, B, 1.0etrovekii 3 has been reported as a material exhibiting chiral smectic liquid crystal in a temperature range relatively close to room temperature.

Also, +t, W, Gray 5 [Mol 0ryst
Liq (3rys't 37 (1976) 189.
48 (197B) 37], a luciferyl ester material exhibiting a chiral smectic liquid crystal phase in a high temperature range has been reported. [Object of the Invention] As described above, the object of the present invention is to The object of the present invention is to provide a useful chiral smectic liquid crystal compound that can be used in an electro-optical device using a ferroelectric liquid crystal in the absence of -C.

[Structure of the invention]

That is, the present invention provides optical activity fz expressed by the following formula (tl
3-chloro, 4--/lucoxyphenyl, 4'-(6-
The present invention relates to methylbutyl)hyphenylcarboxylic acid esters, liquid crystal compositions containing them, and electro-optical elements.

(Here, n is 1 to 12, and * indicates all asymmetric carbon atoms. Kasumi's known biphenyl ester compounds include G, W
, Gray et al. have synthesized a compound represented by the general formula [Mo1.0rye
tLiq 0ryst 48 (1978) 37]
, the phase transition temperatures of these compounds are as follows, 4 81, 7 - 169.3 5 79.8 (70) 164.5 6 6 & 8 80.2 163.5 7 80.4 87.5 1577 8 76 BB, 6 155.4 9 79 89.5 147 10 76.8 95.4 14a5 0 :0r78tal SO”01liral Sme
CtiOnOh = Oholeieric = 1
sotropic 1quid() = monot
ropic Thus, it exhibits a chiral smectic phase with a width of about 10°C around 80°C. The compound of the present invention is a compound of the known (2)
The hydrogen atom at position 3 of the benzene ring on the phenol side of the compound of the formula is replaced with a chlorine atom, and this makes it possible to have a chiral smectic phase at lower temperatures and over a wide range of temperatures. At the same time, it is possible to increase the spontaneous polarization, which greatly affects the characteristics when applied to devices.

〔Example〕

Next, a method for producing the compound of the present invention will be shown.

Commercially available optically active 4/(7-methylbutyl)-4-cyanobiphenyl was hydrolyzed to form 4'-(2-methylbutyl)biphenyl-4-carboxylic acid, and acid chloride was obtained with thionyl chloride to form 3-chloro-4- The compound of the present invention was synthesized by esterifying -n-alkoxyphenol.Hereinafter, a specific method for synthesizing the compound and its properties will be shown in Examples.

Example 1 Optically active 3-chloro-4-n-octyloxyphenyl 4'-(2-methylbutyl)biphenyl-4-carboxylic acid ester 1st stage A/ Production of (2-methylbutyl)biphenyl-4-carboxylic acid 482 ml of sodium hydroxide in a 500 ml flask
．． After adding and dissolving 120 ml of water and 120 ml of ethanol (z), 10f'i of commercially available optically active 4'(2-methyl-phthyl)-4-cyanobiphenyl was added, and the reaction was carried out under heating under reflux for 18 hours.After the completion of the reaction, 1. The mixture was poured into 51 ice water and then acidified with hydrochloric acid to precipitate the carboxylic acid. After separating the mixture at kVr, it was dried and recrystallized to give 4'(2-
Methyl-butyl)biphenyl-4-carboxylic acid y89F
(82%).

Vnujol '2750~2380.1680ma,
x(m-') δ(CD3)2S=Oa30, q, J=9,
AHδ(T(E,D,q)z0=0(pp(1) 7
．． 51, q, J=9. ”'2, Kuhe~2-only 8
m Chloro 2nd stage production of 3-chloro-4-octyloxyphenol In a 200-meter four-necked flask, add 20 chlorohydroquinone.
7. 0-Octyl bromide 242. Anhydrous potassium carbonate17.
3f, 100 mZi of dimethyl formaldehyde was added, and the reaction was carried out at 70 to 80°C under a nitrogen stream for 8 hours. After post-treatment by a conventional method, the obtained oil was purified by silica gel chromatography for 5 tyts, and 3-chloro-4 -Octyloxyphenol 151 was obtained.

fi1m lnll engineering(,,,-+)3380・151゜δCD
C6°TMS (ppm) 6.52-6.93. m, 3H5
, 55, broods, I H 5,42, tJ=6, 2H 5th stage 3-chloro-A-fi-octyloxyphenyl 4-
Preparation of (2-methylbutyl)biphenylcarboxylic acid ester Optically active al (2-methylbutyl)biphenyl-4
Thionyl chloride 5o- was added to -carboxylic acid 51 and reacted under reflux for 6 hours, and then excess thionyl chloride was distilled off under reduced pressure to obtain an oily acid chloride.

(V2: LFl 76 t, 173 tCrn-'
) Obtained 4/(2-methylbutyl)biphenyl-4
-To carboxylic acid chloride, 3-chloro-4-n under water cooling.
-Octyloxyphenol 4.73v.

Dry 1 chestnut pyridine 15m? : The mixture was added and the mixture was slowly returned to room temperature, and the reaction was carried out day and night. After the reaction, a precipitate t
[''Separated and extracted with ether.The organic layer was mixed with water, 2NH
C! 'I! After sequential washing with , 5% NaO)T,
water.

This organic J*' was washed with saturated saline until it became neutral.
The ether was distilled off under reduced pressure to obtain a crude product.

This was repeated and purified to obtain the target gold of 51i' (fo%).

δ0DOl.

'l'Ms (ppm) 7.06~a39, m, 1
1H aromatic hydrogen 2.59. t, T=6,2H, once 10-2,23~z
, s 4. m, 2H-aHw-so>o-The transition temperature of this compound is as follows.

(* indicates supercooling) This compound exhibits an smc* phase in a temperature range close to room temperature, compared to the compound with no at added in n = B in Table 1, and even during that temperature. It's spread out a bit.

This compound was heated and melted and injected into a cell assembled with two substrates having transparent electrodes whose surfaces were gold-rubbed so that the entire rubbing direction was at an angle of 180°, with a gap of 4 μm. did. This liquid crystal cell was slowly cooled from 120°C at a rate of less than 1°C/o. Such a cell′
ff: It was confirmed that the display state changed in response to the switching of the electric field of IH2 when 10 V, II (z alternating current) was applied between two polarizing plates. An electric field of ±10 V was applied at 50°C. The response when applied is 6mB (contrast) 4t, 4
A value of 4 was obtained.

In addition, the measured values of each physical property were measured at 50°C, pitch 2.0pm, cone angle A1°, and spontaneous component @ 1.3x 1 o-'
A value of 0/ca was obtained. The cone angle is close to the value of 45°, which provides the maximum contrast, and the spontaneous polarization exhibits a relatively large value, so it can be said to be a chiral smectic liquid crystal material suitable for electro-optical devices.

Example 2 Optically active 3-chloro-4-n-decyloxyphenyl, 4/(2-methylbutyl)biphenyl-4-carboxylic acid ester Optically active 4/(2″-methylbutyl)biphenyl-4
-carboxylic acid 11 to thionyl chloride 5rn1. Add 6
After reacting under reflux for an hour, excess thionyl chloride was completely distilled off under reduced pressure to obtain an oily acid chloride.

To this acid chloride were added 3-chloro-4-n-decyloxyphenol, o 6 r, and 4 ml of dry pyridine in the same manner as in Example 1 on a water-cooled surface, and the mixture was heated overnight while slowly returning to room temperature. I reacted.

After the reaction was completed, the precipitate was separated and extracted with ether.

The organic layer consists of water, 2NHOI, 5N a, O
The mixture was washed successively with H, water and saturated brine until neutral, and then dried, and the ether was distilled off under reduced pressure. By repeatedly purifying the obtained crude product, the target ester 1.48 f (74 t) was obtained.
-') 17,5 d, 1605, 15808
x 260 δCDCe3 TMS (ppm) IL 87-8.35. m, 11H
.

Aromatic ring hydrogen 4.02, tJ=6.2H, -OH, -0-2,2
8-2.80. m, 2H, -OH, -0- The transition temperature of this compound is as follows.

*52℃ 102℃ (* indicates supercooling) As described above, it was confirmed that the material exhibits a chiral smectic phase in the temperature range close to room temperature, has ferroelectricity, and can be used as a liquid crystal for electro-optical devices. Ta.

Example 3 Optically active 3-700-4-n-hexyloxyphenyl, 4'-(2-methylbutyl)biphenyl-4-carboxylic acid ester Optically active 4-16-methyloctyloxy)benzoic acid 1v chloride Thionyl 10tn1. After reacting under reflux for 6 hours, excess thionyl chloride was completely distilled off under reduced pressure to obtain an oily acid chloride.

3-chloro-4-n-hexyloxyphenol synthesized in the same manner as in Example 1 was added to the obtained acid chloride.
．． 95 tons of dry pyridine 6- were added under water cooling, and the mixture was allowed to react day and night while slowly returning to room temperature. After the reaction,
The precipitate was separated from household to industrial extraction. The organic layer consists of water, 2
After sequentially washing with NHO6, 5% 1JaOH, water,
The mixture was washed with saturated brine until neutral, dried, and all ether was distilled off under reduced pressure. The obtained crude product was purified repeatedly,
Total ester t 16y (61%) was obtained.

δn,t)O13 TMR (ppm) 7.02-a35. m, 11H.

4.02, tT=6, 2H, -CH, -0-2,
22-2.80, m, 2H, OH2-'(2>
-The transition temperature of this compound is:

* 55.1°C 10.2°C (* indicates supercooling) As described above, liquid crystal materials for electro-optical devices exhibit a chiral smectic phase in a temperature range close to room temperature and have ferroelectricity. It was confirmed that it can be used as

Example 4 Compound 3-chloro-4-n-alkoxyphenyl, 4'-(2-methylbutyl)biphenyl-4-carboxylic acid ester of Example 1 of the present invention total 45'41' and known compound 4' -nonyloxybenzoic acid, aJJ (2
-Methylbutyloxy)phenyl ester (55% by weight) was dissolved in a mixed bath to obtain a liquid crystal composition.

This liquid crystal composition exhibited an SC phase in the range of 34°C to 58°C and exhibited ferroelectricity.
The mixture was melted in a heating bath, poured into a liquid crystal cell having the same configuration as above and having a gap of 2.5 μm, and slowly cooled to 40°C. This liquid crystal cell is sandwiched between two polarizing plates whose polarization axes are perpendicular to each other, a voltage is applied, and the polarity is +! When + is reversed, the display status is on-off
f was observed. The axial directions of these two polarizing plates were set to obtain the maximum contrast, and ±1 at 40°C was set.
When a full voltage of 0.0 cm was applied, characteristics of a contrast of 18 and a response speed of 2.1 mday were obtained.

〔Effect of the invention〕

As shown in the examples above, the compound of the present invention is a useful liquid crystal material that exhibits a -('sc* phase near room temperature and has a ferromagnetic strength), and is a chiral material that exhibits a chiral structure in a wide temperature range including room temperature. It can be an effective component in obtaining smectic liquid crystal compositions.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of the smectic C phase or iH phase, and FIG. 2 is a schematic diagram showing the movement of liquid crystal molecules in the chiral smectic phase along a cone due to an electric field. that's all

Claims (1)

[Claims] il+ Optically active 3-chloro represented by the general formula (in the above formula, n is 1 to 12, and the * mark indicates an asymmetric carbon atom). A liquid crystal chemical substance having a structure of 4-n-alkoxyphenyl, 4'-(2-methylbutyl)piphenyl-4-carboxylic acid ester.