JPH07126199A - Difluoroethylene derivative compound and liquid crystal composition containing the compound - Google Patents

Abstract

PURPOSE:To provide the novel compound having excellent refractive index anisotropy, compatibility with other (non)liquid crystal substances, chemical stability, light stability, etc., and low viscosity and useful as a liquid crystal composition, liquid crystal electrooptical element, etc. CONSTITUTION:A compound of the formula I [A<3> is trans-1,4-cyclohexylene; A<1>, A<2> and A<4> are (substituted) A<3>, (substituted) 1,4-phenylene, etc.; Y<1> and Y<2> are COO, CidenticalC, single bond, etc.; R<1> and R<2> are 1-10C alkyl, halogen, cyano, etc.; (m) and (n) are 0 or 1], e.g. (E)-1-(4-chlorophenyl)-2-(trans-4-n- propylcyclohexyl)-1,2-difluoroethylene. The compound of the formula I can be produced by using a compound of the formula II (Cy is A<2>) as a starting substance to obtain a compound of the formula III and reacting the compound with a compound of the formula IV.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a difluoroethylene derivative compound and a liquid crystal composition containing the same.

[0002]

2. Description of the Related Art Liquid crystal display devices include clocks, calculators,
In recent years, measuring instruments, automobile instruments, copying machines, cameras, OA
It has begun to be used in various applications such as device display devices and home appliance display devices, and various performance requirements such as wide operating temperature range, low operating voltage, high-speed response, high contrast ratio, wide viewing angle, chemical stability, etc. Has been done.

However, at present, there is no material satisfying all of these characteristics with a single material, and a plurality of liquid crystal and non-liquid crystal materials are mixed to satisfy the required performance as a liquid crystal composition. For this reason, it is desired to develop a liquid crystal or non-liquid crystal material that is excellent in one or two or more of all the characteristics.

[0004]

In the field of display devices using liquid crystals, it is desired to improve their performance, and low voltage driving, high definition display, high contrast ratio, wide viewing angle characteristics, low temperature response characteristics, wide operation are required. Temperature ranges and the like are desired, and any one of them tends to be sacrificed when the other is improved.

In particular, recently, low voltage drive and high speed response in battery drive, high definition display and high speed response in OA equipment, low temperature response in automobile display etc. or high speed response in wide operating temperature range have been made. It is desired to improve the response speed.

To solve this problem, some improvement methods can be considered. One of them is to adopt a low viscosity liquid crystal composition. That is, if the viscosity of the liquid crystal composition is reduced, the response speed is improved, and it is possible to display at a practical speed even at low temperatures. Further, if the response speed is the same as that of the conventional one, it is possible to drive with a lower voltage or drive with a higher duty, that is, high-definition drive becomes possible.

For such a purpose, JP-A-3-410 is used.
37 or as disclosed in JP-A-3-294386.
P, p'-disubstituted difluorostilbene compounds have been proposed. This compound has a chemical structure represented by the following general formula (3).

[0008]

[Chemical 3]

However, R ^A and R ^{B in} the general formula (3) mean an n-alkyl group, an n-alkoxy group and an n-alkoxycarbonyl group.

The compound of the general formula (3) had low viscosity and improved stability to light as compared with a stilbene compound which was not substituted with fluorine. However, the stability against light is still inferior to the commonly used general liquid crystal compounds, and the use environment is limited, and it is often necessary to use an ultraviolet cut filter together. Therefore, a liquid crystal material having low viscosity and high stability to light has been desired.

[0011]

The present invention provides a novel material for solving the above problems, and provides a difluoroethylene derivative compound represented by the following general formula (1). .

[0012]

[Chemical 4]

However, in the general formula (1), A ¹ , A ² , A ³ , A ⁴ ,
Y ¹ , Y ² , R ¹ , R ² , m and n are as follows.

A ³ is a trans-1,4-cyclohexylene group, and A ¹ , A ² and A ⁴ are independently of each other a trans-1,4-cyclohexylene group, a 1,4-phenylene group, or 1,4-cyclohexenylene group, each of these ring groups is unsubstituted or has at least one halogen atom or cyano group as a substituent, and forms a ring in these ring groups. more than five = CH- group may be substituted by nitrogen atoms, also one or more -CH ₂ - constituting the ring - group may be replaced by an oxygen atom or a sulfur atom.

Y ¹ and Y ² are independently of each other -COO-, -OCO-,
_{-C≡C -, - CH 2 CH 2} -, - CH = CH-, -OCH 2 -, - shows a CH ₂ O- or a single bond.

R ¹ and R ² each independently represent an alkyl group having 1 to 10 carbon atoms, a halogen atom or a cyano group, and in the case of an alkyl group, between carbon-carbon bonds in the alkyl group or An oxygen atom, a carbonyloxy group, or an oxycarbonyl group may be inserted between the carbon-carbon bond between the alkyl group and the ring group, and a part of the carbon-carbon bond in the alkyl group is a triple bond. Alternatively, it may be a double bond, and one —CH ₂ — group in the alkyl group may be substituted with a carbonyl group, and a part of hydrogen atoms in the alkyl group or All may be substituted with fluorine atoms, and R ¹ , R ²
At least one of them is a chlorine atom or a group in which a part of the carbon-carbon bond has a triple bond or a double bond.

M and n each independently represent 0 or 1.

Further, the present invention is represented by the following general formula (2) (wherein A ² , A ³ , R ¹ and R ² in the general formula (2) are the same as those in the general formula (1)). The present invention provides a difluoroethylene derivative compound represented.

[0019]

[Chemical 5]

Furthermore, the present invention provides a liquid crystal compound comprising the compound of the general formula (1) or the general formula (2) and a liquid crystal composition containing the compound of the general formula (1) or the general formula (2). It is intended to provide a liquid crystal electro-optical element in which those liquid crystal compounds or liquid crystal compositions are sandwiched between substrates with electrodes.

The compound of the general formula (1) of the present invention has a relatively large refractive index anisotropy (Δn), has a low viscosity, and is compatible with other liquid crystals or non-liquid crystals. It is an excellent and chemically stable material.

Further, the compound of the general formula (1) of the compound of the present invention is more stable to light and has improved durability (K ₃₃ ) than the compound of the general formula (3) described above. / K
₁₁ ) increases and the contrast increases, and the maximum liquid crystal temperature (T
_C ) is increased, the temperature range of the liquid crystal is increased, the viscosity (η) is decreased, which is advantageous for high-speed response.

Particularly as a liquid crystal material for high-speed STN, a general formula
It is more advantageous and useful than the compound of (3).

Specific structures of the compounds of the present invention include the following compounds. As typical compounds thereof, there are the following compounds as compounds having two rings.

[0025]

[Chemical 6]

More specifically, the compound of the general formula (4) includes the following compounds. In the following description, not only the compound of the general formula (4) but also “-Ph-” is 1,
Represents a 4-phenylene group, "-Cy-" represents a trans-1,4-cyclohexylene group, "-Ch-" is a 1,4-cyclohexenylene group, preferably 1-cyclohexene-1,4- It represents an ylene group, and “PhF” represents a monofluoro-1,4-phenylene group or a polyfluoro-1,4-phenylene group. Further, i represents an integer of 1 to 4.

[0027]

[Chemical 7]

The following compounds are examples of compounds having three rings.

[0029]

[Chemical 8]

More specifically, the compound of the general formula (5) includes the following compounds.

[0031]

[Chemical 9]

Further, as a compound having four rings, there are the following compounds.

[0033]

[Chemical 10]

More specifically, the compound of the general formula (6) includes the following compounds.

[0035]

[Chemical 11]

[0036]

[Chemical 12]

In addition, in the case of a compound having three or more rings, there are the following compounds in which Y ¹ and Y ² between the rings are changed to other than a single bond.

[0038]

[Chemical 13]

[0039]

[Chemical 14]

Further, A ³ may be a group in which a part of hydrogen atoms of trans-1,4-cyclohexylene group is replaced with a halogen atom or a cyano group. Further, it may be a group in which a part of hydrogen atoms of the ring group of A ¹ , A ² and A ⁴ is replaced with a halogen atom or a cyano group, or a part of = CH- group constituting the ring is replaced with a nitrogen atom. Alternatively, the following compounds may be mentioned as examples in which a part of the —CH ₂ — group constituting the ring is replaced with an oxygen atom or a sulfur atom.

[0041]

[Chemical 15]

At least one compound of the above-mentioned general formula (1) of the present invention is mixed with other liquid crystal material and / or non-liquid crystal material to be used as a liquid crystal composition. As a result, the liquid crystal composition can have a low viscosity, and high-speed response can be achieved when the liquid crystal display device is used.

Examples of substances to be mixed with the compound of the present invention are as follows. In the formulas below, R ^C and R ^D are an alkyl group, an alkoxy group, a halogen atom,
Represents a group such as a cyano group. Moreover, "-NON-" represents an azoxy group.

[0044]

[Chemical 16]

[0045]

[Chemical 17]

These compounds are merely examples, and the hydrogen atom of the ring structure or the terminal group may be replaced with a halogen atom, a cyano group, a methyl group or the like, and other six members of the cyclohexane ring and the benzene ring. Ring, five-membered ring, for example,
It may be substituted with a pyridine ring, a dioxane ring, or the like, and the bonding group between the rings may be changed, and various materials may be selected and used according to the desired performance.

The liquid crystal composition containing the compound of the present invention is sandwiched between substrates with electrodes by injection into a liquid crystal cell or the like to form a liquid crystal electro-optical element.

As a typical liquid crystal cell, there is a twist nematic (TN) type liquid crystal electro-optical element. The expression "liquid crystal electro-optical element" is used here because it is clarified that the liquid crystal electro-optical element can be used for a light control window, an optical shutter, a polarization exchange element, etc., in addition to the display application.

The liquid crystal electro-optical element is used in various modes such as a TN system, a guest-host (GH) system, a dynamic scattering system, a phase change system, a DAP system, a dual frequency drive system and a ferroelectric liquid crystal display system. can do.

Specific examples of the structure and manufacturing method of the liquid crystal electro-optical element will be shown below. If necessary, an undercoat layer such as SiO ₂ or Al ₂ O ₃ or a color filter layer may be formed on a substrate such as plastic or glass, and In ₂ O ₃ -SnO ₂ (ITO),
After providing an electrode such as SnO ₂ and patterning, if necessary, form an overcoat layer of polyimide, polyamide, SiO ₂ , Al ₂ O _3, etc., perform orientation treatment, print a sealing material on this, and print the electrode surface Are arranged so that they face each other, and the periphery is sealed,
The sealing material is cured to form an empty cell.

A composition containing the compound of the present invention is injected into this empty cell, and the injection port is sealed with a sealant to form a liquid crystal cell. If necessary, a polarizing plate, a color polarizing plate, a light source, a color filter, a semi-transmissive reflector, a reflector,
Laminated light guide plate, UV cut filter, etc., letters,
A liquid crystal electro-optical element is obtained by printing a figure or the like or performing non-glare processing.

The above description merely shows the basic constitution and manufacturing method of the liquid crystal electro-optical element.
Various structures such as a substrate using a layer electrode, a two-layer liquid crystal cell in which two liquid crystal layers are formed, an active matrix element using an active matrix substrate in which active elements such as TFT and MIM are formed can be used.

By using the compound of the present invention in a liquid crystal composition, a high speed response can be expected even when high duty driving is performed. Therefore, it is suitable for a super twist (STN) type liquid crystal electro-optical element having a high twist angle, which has been receiving attention in recent years. In addition, it can also be used for a GH type liquid crystal display device using a polychromatic dye, a ferroelectric liquid crystal electro-optical device, and the like.

The compound of the general formula (1) of the present invention is, for example,
It is manufactured according to the following method.

[0055]

[Chemical 18]

In the above formula, A ³ is a trans-1,4-cyclohexylene group, and A ¹ , A ² and A ⁴ are independently of each other a trans-1,4-cyclohexylene group, 1, 4-phenylene group,
Or a 1,4-cyclohexenylene group, and each of these ring groups is unsubstituted or has at least one halogen atom or cyano group as a substituent and constitutes a ring in these ring groups. One or more ═CH— groups may be substituted with a nitrogen atom, and one or more —CH ₂ — groups constituting the ring may be substituted with an oxygen atom or a sulfur atom.

Y ¹ and Y ² are independently of each other -COO-, -OCO-,
_{-C≡C -, - CH 2 CH 2} -, - CH = CH-, -OCH 2 -, - shows a CH ₂ O- or a single bond.

R ¹ and R ² each independently represent an alkyl group having 1 to 10 carbon atoms, a halogen atom or a cyano group, and in the case of an alkyl group, between carbon-carbon bonds in this alkyl group or this An oxygen atom, a carbonyloxy group, or an oxycarbonyl group may be inserted between the carbon-carbon bond between the alkyl group and the ring group, and a part of the carbon-carbon bond in the alkyl group is a triple bond. Alternatively, it may be a double bond, and one —CH ₂ — group in the alkyl group may be substituted with a carbonyl group, and a part of hydrogen atoms in the alkyl group or All may be substituted with fluorine atoms, and R ¹ , R ²
At least one of them is a chlorine atom or a group in which a part of the carbon-carbon bond has a triple bond or a double bond.

The carboxylic acid derivative of formula (10) is reduced with lithium aluminum hydride to give the alcohol derivative of formula (11). Next, the compound (11) is oxidized with pyridinium chlorochromate to give an aldehyde derivative of the formula (12).

Then, the obtained compound (12) is reacted with dibromodifluoromethane and trisdimethylaminophosphine to give a 1,1-difluoroethylene compound of the general formula (13). Then, it is fluorinated with cobalt trifluoride to give a 1,1,1,2-tetrafluoroethane compound of formula (14), which is de-HFed with t-butyllithium to give trifluoroethylene of formula (15). It is a compound. Finally, by reacting with the lithium compound of formula (16), the difluoro compound of general formula (1) can be obtained.

The method of introducing an acyl group into R ¹ and R ² of the compound represented by the general formula (1) can be carried out by the general formula in which R ¹ and R ² are hydrogen atoms.
The Friedel-Crafts reaction between the compound (1) and an acyl halide may be used. In addition, the method of introducing a cyano group is represented by the general formula in which R ¹ and R ² are bromine atoms or iodine atoms.
The compound (1) may be reacted with CuCN. Also, the general formula
The method of introducing a vinylidene group (-C = C-) into Y ¹ of the compound of (1) is carried out by the compound of the general formula (1) in which R ¹ and R ² are chlorine atom, bromine atom or iodine atom and an alkenyl group. A coupling reaction with a linear compound may be used. Further, a method of introducing an ethylidene group (-C≡C-) into Y ¹ of the compound of the general formula (1) is carried out by using a compound of the general formula (1) in which R ¹ and R ² are bromine atoms or iodine atoms A coupling reaction with a lithium compound may be used.

[0062]

【Example】

[Example 1] <First step> 22.3 g (0.588 mo) of lithium aluminum hydride (LiAiH ₄ ) was added to a 1-liter four-necked flask.
l) and tetrahydrofuran (THF) 300 ml, 0
Cooled to ° C. A solution of 100 g (0.588 mol) of trans-4-n-propylcyclohexanecarboxylic acid dissolved in 300 ml of THF was added dropwise with stirring at 10 ° C. or lower over 2 hours. After stirring at room temperature for 12 hours, 200 ml of 20% sulfuric acid aqueous solution was added, extracted with ether, washed with water, dried, evaporated to remove the solvent, and further distilled under reduced pressure (88 ° C / 4mmHg).
Trans-4-n-propylcyclohexanemethanol (n-
The _{C 3 H 7 -Cy-CH 2} OH) to give 89.3 g (97% yield).

<Second Step> Next, 37 g of pyridinium chlorochromate (PCC) was placed in a 2-liter four-necked flask.
0.2 g (1.717 mol), sodium acetate 23.5 g (0.286 mol) and methylene chloride 1.2 liter were charged, and at room temperature, trans-4-n-propylcyclohexanemethanol 89.3 g (0.572 mol) was chlorinated. The methylene solution was added dropwise. After stirring for 1 hour at room temperature, add 1 liter of ether,
Further anhydrous MgSO ₄ was added, and the tar-like substance was filtered off.
The filtrate was concentrated under reduced pressure, 200 ml of ether was added again, and the tar-like substance was filtered off. The filtrate after concentrated under reduced pressure, and purified by silica gel column chromatography, the further resulting crude liquid was distilled under reduced pressure (64 ℃ / 3mmHg), trans -4-n-propyl cyclohexane aldehyde (nC ₃ H ₇ -Cy- CHO) 5
6.0 g (yield 64%) was obtained.

<Third Step> 400 ml of triglyme dehydrated with CaH ₂ was placed in a 1-liter four-necked flask equipped with a cooling tube and a gas blowing tube, cooled to 0 ° C., and dibromodifluoromethane (CF ₂ Br ₂ ) was added. Was blown in at 101 g (0.481 mol). Then, at 0 ° C., 156.7 g (0.961 mol) of trisdimethylaminophosphine (Me ₂ N) ₃ P and 200 ml of a triglyme solution were added dropwise over 15 minutes. After dropping, stir for 15 minutes at room temperature, then add 37.0 g (0.24 mol) of trans-4-n-propylcyclohexanaldehyde and 100 ml of triglyme solution obtained above at room temperature over 15 minutes, and then add 85 ° C.
Was reacted for 2 hours.

After cooling to 0 ° C., 300 ml of water was added, extracted with n-hexane, washed with water and dried, the solvent was distilled off, and the obtained crude liquid was purified by silica gel column chromatography.
Furthermore, the crude liquid obtained was distilled under reduced pressure (78 ° C / 20 mmHg) to give 2-
28.6 g of (trans-4-n-propylcyclohexyl) -1,1-difluoroethylene (nC ₃ H ₇ -Cy-CH = CF ₂ ) (yield 63
%)Obtained.

<Fourth Step> 28.6 g (0.152 mol) of 2- (trans-4-n-propylcyclohexyl) -1,1-difluoroethylene obtained above was placed in a 2 liter autoclave.
l), 123.4 g (1.06 mol) of cobalt trifluoride, 1 ml of water and 1000 ml of FC-113 (CCl ₂ FCClF ₂ ) were charged, and 3
Reacted for hours. After cooling, the inorganic salt was filtered off and the organic layer was washed with 10
% NaHCO ₃ aqueous solution, further washed with water, the solvent was distilled off, and the resulting crude liquid was purified by silica gel column chromatography to give 2- (trans-4-n-propylcyclohexyl) -1,1. , 1,2-Tetrafluoroethane (nC ₃ H ₇ -Cy-
15.5 g (purity 86%) of a crude liquid of CHFCF ₃ ) was obtained.

<Fifth Step> In a 1-liter four-necked flask, a crude liquid of the previously obtained 2- (trans-4-n-propylcyclohexyl) -1,1,1,2-tetrafluoroethane 15.5 was added.
g and 200 ml of dry THF were charged and cooled to -78 ° C. Then, a solution of t-BuLi in n-pentane (1.6 mol / liter) was added to 44.2.
ml (0.07 mol) was added dropwise over 30 minutes. After reacting at -78 ° C for 2 hours, warm to room temperature and add 1N hydrochloric acid to 500m.
l In addition, the organic layer was separated. The aqueous layer was extracted with n-hexane, washed with water together with the organic layer, dried, the solvent was distilled off, and the resulting crude liquid was purified by silica gel column chromatography to give 2- (trans-4-n -Propylcyclohexyl) -1,1,2-trifluoroethylene (nC ₃ H ₇ -Cy-CF = C
F ₂₎ to give 7.53 g (62% yield).

<Sixth Step> To a 300 ml four-necked flask, 6.02 g (25.2 mmol) of 4-chloroiodobenzene and 30 ml of dry ether were charged and cooled to -78 ° C. Then
17 ml (2 ml) of n-BuLi in n-hexane (1.63 mol / liter)
7.8 mmol) and added dropwise over 15 minutes. Furthermore, at -78 ℃
After stirring for an hour, 3.8 ml of tetramethylenediamine (TMEDA)
(25.5 mmol) was added, and the 2- (trans-
A mixed solution of 1.3 g (6.31 mmol) of 4-n-propylcyclohexyl) -1,1,2-trifluoroethylene and 60 ml of dry THF was added dropwise over 30 minutes. After reacting for 2 hours at the same temperature, the temperature was raised to room temperature, 500 ml of 1N hydrochloric acid was added, and the organic layer was separated. The aqueous layer was extracted with n-hexane, and the organic layer was washed with water and dried, the solvent was distilled off, the crude liquid obtained was purified by silica gel column chromatography, and the obtained solid was re-purified from methanol. Crystallized to give (E) -1- (4-chlorophenyl) -2- (trans-4-n-propylcyclohexyl) -1,2-difluoroethylene (nC ₃ H ₇ -Cy-CF = CF-Ph
-Cl) was obtained in an amount of 0.66 g (yield 35%).

[0069]

[Chemical 19]

The analysis results of this compound are shown in Table 1.

The following compounds can be obtained in the same manner as in Example 1.

[0072]

[Chemical 20]

[Example 2] In the sixth step of Example 1, 1-methyl-2- was used instead of 4-chloroiodobenzene.
The reaction was performed in the same manner as in Example 1 except that 6.10 g (25.2 mmol) of (4-iodophenyl) acetylene was used, and (E) -1- (4-
(Propyl-1-yne) phenyl) -2- (trans-4-n-)
Propylcyclohexyl) -1,2-difluoroethylene (nC ₃ H ₇ -Cy-CF = CF-Ph-C≡CCH ₃ ) 0.47 g (yield 25%)
Obtained.

[0074]

[Chemical 21]

The analysis results of this compound are shown in Table 2.

The following compounds can be obtained in the same manner as in Example 2.

[0077]

[Chemical formula 22]

[Example 3] In the sixth step of Example 1, trans-1- was used instead of 4-chloroiodobenzene.
6.15 g (25.2%) of methyl-2- (4-iodophenyl) vinylene
mmol), except that the reaction is carried out in the same manner as in Example 1, (E)-
1- (4- (trans-1-propylene) phenyl) -2- (trans-4-n-propylcyclohexyl) -1,2-difluoroethylene (nC ₃ H ₇ -Cy-CF = CF-Ph-CH = CHCH ₃ ) 0.42g
(Yield 22%) was obtained.

[0079]

[Chemical formula 23]

Table 3 shows the analysis results of this compound.

The following compounds can be obtained in the same manner as in Example 3.

[0082]

[Chemical formula 24]

[Example 4] Liquid crystal composition "ZLI-" manufactured by Merck & Co., Inc.
1565 ”to 80 wt% of the compound (E) -1- (4-chlorophenyl) -2- (trans-4-n-propylcyclohexyl) -1,2-difluoroethylene of Example 1 was added at 20 wt% to obtain a liquid crystal composition. did. Table 4 shows the liquid crystal properties of the present liquid crystal composition. Table 4
As is clear, the compound of the present invention has a low viscosity and a high Δn.
It is a compound and is useful as a liquid crystal material for high-speed STN.

Example 5 Compound (E) -1- of Example 2
(4- (Propyl-1-yne) phenyl) -2- (trans-4
The NI point (Tc) of -n-propylcyclohexyl) -1,2-difluoroethylene was 134.6 ° C. Further, 20 wt% of the compound of Example 2 was added to 80 wt% of the liquid crystal composition "ZLI-1565" manufactured by Merck & Co., Inc. to give a liquid crystal composition. Table 5 shows the liquid crystal properties of the present liquid crystal composition.

[Example 6 and Comparative Examples 1 and 2] Liquid crystal composition "ZLI-1565" manufactured by Merck & Co., Ltd. was added to 80% by weight of Example 1 of the present invention.
20 wt% of the compound was added to obtain a liquid crystal composition (Example 6). As a comparative example, a liquid crystal composition "ZLI-1565" manufactured by Merck & Co., Inc.
Liquid crystal composition of Comparative Example 1 (Comparative Example 1) and liquid crystal composition of 20% by weight of trans-4,4′-bis- (n-propyl) difluorostilbene added to 80% by weight of liquid crystal composition “ZLI-1565” manufactured by Merck Ltd. ( Comparative example 2) was prepared. These were enclosed in a liquid crystal cell with a polarizing plate to prepare an STN type liquid crystal display element.

The display characteristics of the liquid crystal display elements of Example 6 and Comparative Example 2 were substantially the same, and a higher speed response than that of the element of Comparative Example 1 was obtained. Next, the liquid crystal display elements of Example 6 and Comparative Example 2 were irradiated with an ultraviolet carbon arc lamp for 500 hours. After irradiation, the liquid crystal composition in each device was analyzed.

As a result, in the case of the liquid crystal composition of Example 6, 0.6% (Z) -1- (4-chlorophenyl) -2- (trans
-4-n-Propylcyclohexyl) -1,2-difluoroethylene was produced. On the other hand, in the case of the liquid crystal composition of Comparative Example 2, it was confirmed that 6.3% of (Z) -4,4′-bis- (n-propyl) difluorostilbene was produced.

[Embodiment 7] In Embodiment 6, (E) -1-
Instead of (4-chlorophenyl) -2- (trans-4-n-propylcyclohexyl) -1,2-difluoroethylene,
Carried out except that (E) -1- (4- (propyl-1-yne) phenyl) -2- (trans-4-n-propylcyclohexyl) -1,2-difluoroethylene obtained in Example 2 is used. Example 6
UV irradiation with 0.5% of (E) -1- (4- (propyl-1-yne) phenyl) -2- (trans-4-n-propylcyclohexyl) -1,2-difluoroethylene Generated.

[0089]

[Table 1]

[0090]

[Table 2]

[0091]

[Table 3]

[0092]

[Table 4]

[0093]

[Table 5]

[0094]

The general formula (1) R ^1- (A ¹ ) _m -Y ¹ -A ² -CF = CF-A ³ -Y ^2- (A ⁴ ) _n -R ² (A ¹ ~ A ⁴ , R ¹ , R ² , Y ¹ , Y ² , m, and n have the above-mentioned meanings), and the compound has a low viscosity and a large Δn, and is used as a liquid crystal composition. As a result, the response speed is improved even with a small amount of addition, and low voltage driving, high duty driving, wide temperature range operation, etc. are possible.

Further, compared with the difluorostilbene type liquid crystal, it is more stable to ultraviolet light and has improved durability.
The elastic modulus (K ₃₃ / K ₁₁ ) increases and the contrast becomes high,
Liquid crystal upper limit temperature (T _C) is a liquid crystal temperature range is increased to rise,
It is a material with improved properties such as reduced viscosity (η), which is advantageous for high-speed response.

Particularly, as a liquid crystal material for high speed STN, it is superior to difluorostilbene type liquid crystal and useful.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location C07C 43/192 43/225 C 7419-4H 69/75 A 9279-4H 69/757 C 9279-4H 69/76 A 9279-4H 69/773 69/92 9279-4H 255/53 255/54 255/55 C07D 239/26 C09K 19/16 9279-4H 19/18 9279-4H 19/20 9279-4H 19 / 28 9279-4H 19/30 9279-4H 19/38 9279-4H G02F 1/13 500 (72) Inventor Hidemasa Taka 1150 Hazawa-cho, Kanagawa-ku, Yokohama, Kanagawa Prefecture Asahi Glass Co., Ltd. Central Research Laboratory (72) Inventor Keiko Oike 1150, Hazawa-machi, Kanagawa-ku, Yokohama, Kanagawa Prefecture Asahi Glass Co., Ltd. Central Research Laboratory (72) Inventor Jun Irizawa 1150, Hazawa-machi, Kanagawa-ku, Yokohama City, Kanagawa Prefecture Asahi Glass Co., Ltd. Central Research Laboratory (72) Inventor Sachi Machida Kanagawa Samukawa, Takaza-gun, prefecture Okada 4-16-31

Claims (5)

[Claims] 1. A difluoroethylene derivative compound represented by the following general formula (1). Embedded image R ^1- (A ¹ ) _m -Y ¹ -A ² -CF = CF-A ³ -Y ^2- (A ⁴ ) _n -R ² (1) However, in the general formula (1), A ¹ , A ² , A ³ , A ⁴ , Y ¹ , Y ² , R ¹ ,
R ² , m and n are as follows. A ³ is a trans-1,4-cyclohexylene group, and A ¹ , A ² , and A ⁴ are independently of each other a trans-1,4-cyclohexylene group, a 1,4-phenylene group, or a 1,4 -A cyclohexenylene group, each of these ring groups is unsubstituted or has one or more halogen atoms or cyano groups as substituents, and one or more of the ring groups in these ring groups are The ═CH— group may be substituted with a nitrogen atom, and one or more —CH ₂ — groups constituting the ring may be substituted with an oxygen atom or a sulfur atom.
Y ¹ and Y ² are independently of each other -COO-, -OCO-, -C≡C-, -CH ₂
CH _2- , -CH = CH-, -OCH _2- , -CH ₂ O- or a single bond is shown.
R ¹ and R ² each independently represent an alkyl group having 1 to 10 carbon atoms, a halogen atom or a cyano group, and in the case of an alkyl group, between the carbon-carbon bond in the alkyl group or the alkyl group. An oxygen atom, a carbonyloxy group, or an oxycarbonyl group may be inserted between the carbon-carbon bond between the ring group and the carbon atom in the alkyl group.
A part of the carbon bond may be a triple bond or a double bond, and one -CH _2- group in the alkyl group may be substituted with a carbonyl group. A part or all of hydrogen atoms therein may be substituted with a fluorine atom, and at least one of R ¹ and R ² is a chlorine atom or a part of carbon-carbon bond is a triple bond or a divalent bond. It is a group having a heavy bond. m, n
Are 0 or 1 independently of each other. 2. The following general formula (2) (wherein the general formula (2)
The difluoroethylene derivative compound according to claim 1, which is represented by general formula (1) for A ² , A ³ , R ¹ and R ² . [Chemical formula 2] R ¹ -A ² -CF = CF-A ³ -R ² (2) 3. A compound having liquid crystallinity selected from the difluoroethylene derivative according to claim 1. 4. A liquid crystal composition containing at least one difluoroethylene derivative compound according to claim 1. 5. A liquid crystal electro-optical element comprising a liquid crystal compound according to claim 3 or a liquid crystal composition according to claim 4 sandwiched between substrates with electrodes.