TWI608083B - Liquid crystal compound having (difluoro) ethylene glycol-based structure and liquid crystal composition - Google Patents

Description

Liquid crystal compound having a (difluoro)ethylene diether structure and liquid crystal combination

The present invention relates to a liquid crystal compound and a liquid crystal composition including the liquid crystal compound, and particularly to a liquid crystal compound having a (difluoro)ethylene diether structure and a liquid crystal composition including the liquid crystal compound.

Liquid crystal materials are mainly used in the dielectric of liquid crystal displays because the applied voltage can change the optical properties of such materials. Liquid crystal based electro-optical devices are well known to those skilled in the art and can encompass a variety of effects. Examples of such devices are liquid crystal cells with dynamic scattering, DAP (Aligned Phase Deformation) liquid crystal cells, guest/host type liquid crystal cells, TN boxes with twisted nematic structure, STN (Super Twisted Nematic) liquid crystal cells, SBE ( Super birefringence effect) Liquid crystal cell and OMI (light film interference) liquid crystal cell. The most common displays are based on the Schadt-Helfrich effect and have a twisted nematic structure. In addition, there are liquid crystal cells for electric field operation parallel to the substrate and the liquid crystal surface, such as an IPS (In-Plane Switching) liquid crystal cell. In particular, TN, STN and IPS liquid crystal cells, especially TN and IPS liquid crystal cells are currently commercially useful applications.

The liquid crystal material must have good chemical and thermal stability and good stability against electric fields and electromagnetic radiation. In addition, the liquid crystal material should have a low viscosity and produce short reaction times, low threshold voltages, and high contrast in the liquid crystal cell. They should also have a liquid crystal phase suitable for the above liquid crystal cell, such as a nematic or cholesteric liquid crystal phase, at ordinary operating temperatures, i.e., at the widest possible range above and below room temperature. However, liquid crystals are usually used in a mixture of a plurality of components, and these components are easily miscible with each other. In addition, other properties of the liquid crystal such as electrical conductivity, dielectric anisotropy, and optical anisotropy must satisfy various requirements depending on the type of liquid crystal cell and the field of application.

Using mixed liquid crystals on MLC displays, notebook computers, or car meters, in addition to problems related to contrast and reaction time, it is difficult to achieve high resistivity. As the resistivity decreases, the contrast of the display will It deteriorates and may cause problems with the afterimage disappearing. For TV and video applications, displays with short response times are needed. In particular, such a short reaction time can be achieved if a liquid crystal composition having a low viscosity value is used. However, the dilution additive generally reduces the clarification point and thereby reduces the operating range of the mixed liquid crystal. As in the TN liquid crystal cell, there is a need for a medium that contributes to the following advantages in the liquid crystal cell: (1) an extended nematic phase range (especially low to low temperature); (2) switchability at very low temperatures; (3) ) improved resistance to ultraviolet radiation; (4) low threshold voltage.

However, the hybrid liquid crystal obtained in the prior art cannot achieve these advantages while maintaining other parameters. Therefore, there is still a great need for poles that do not exhibit these shortcomings or that exhibit these characteristics to a lesser extent. High resistivity, high dielectric anisotropy, mixed liquid crystal with large operating temperature range, short reaction time (even at low temperatures) and low threshold voltage.

Accordingly, it is an object of the present invention to provide a liquid crystal compound having a (difluoro)ethylene diether structure. The liquid crystal compound has good chemical and physical stability and low birefringence, and a liquid crystal compound containing the structure as a negative liquid crystal will cause a liquid crystal display element to have a larger dielectric anisotropy.

Thus, the liquid crystal compound of the present invention having a (difluoro)ethylenediether structure is represented by the general formula (I): Wherein R ₁ and R ₂ each independently represent -H, -F, -Cl, -CN, -NCS, -SCN, -OCN, -NCO, , Unsubstituted C linear or branched alkyl group of ₁ to C ₂₀ straight-chain or branched-chain alkyl group with at least one halogen-substituted C ₁ to C ₂₀ or C ₁ to C ₂₀ alkoxy is a base wherein at least one of _-1 -CH ₂ - in said R ₁ and said R ₂ may be -O-, -S-, -SiH ₂ -, -CH=CH-, -C≡C-, -CF =CF-, -CH=CF-, , -COO- or -OCO-substitution, provided that the heteroatoms are not directly bonded to each other; the rings A ₁ , A ₂ , A ₃ , A ₄ and A _{5 are the} same or different and are each independently represented as a cyclic structure, and Ring structure representation , Wherein, the cyclic structure may also conform to at least one of the following a), b), c) and d): a) one or more hydrogen atoms in the cyclic structure may be -D, -F, -Cl, -CN, -CF ₃ , -OCF ₃ , -CH ₂ F, -OCH ₂ F, -CF ₂ H , -OCF ₂ H, -OCH ₃ or -CH ₃ substitution; b) the cyclic structure One or more -CH ₂ - is substituted by -O-, -SiH ₂ -, -S- or -CO-, provided that the heteroatoms are not directly bonded to each other; c) in the cyclic structure, the aromatic ring One or more -CH- in the structure may be substituted by -N-; d) one or more of the cyclic structures Can be Substituting; and, the A ₁ can also represent , , or , the A ₅ can also represent R ⁴ , R ⁴ , R ⁴ or R ⁴ , wherein R ₃ and R ₄ are as defined for R ₁ and R ₂ ; Z ₁ , Z ₂ , Z ₃ and Z _{4 are the} same or different and each independently represents a single bond, —COO—, —CF ₂ O— , -CH ₂ O-, -OCH ₂ -, -CH ₂ CH ₂ -, -CF ₂ CH ₂ -, -CF=CF-, -CH=CH-, -CH=CF-, -C ₂ F ₄ - , -(CH ₂ ) ₄ -, -(CF ₂ ) ₄ -, -OCF ₂ CF ₂ O-, -CF ₂ CF ₂ CF ₂ O-, -CH ₂ CH ₂ CF ₂ O-, -OCH ₂ CF ₂ O-, -OCH ₂ CHFO-, -OCHFCH ₂ O-, -OCF ₂ CH ₂ O-, -CH ₂ CF ₂ OCH ₂ -, -CH=CHCF ₂ O-, -CF ₂ OCH=CH-, -CF ₂ OCF=CH-, -CF ₂ OCH=CF-, -CF=CFCF ₂ O-, -CF ₂ OCF=CF-, -C ₂ H ₄ OCH ₂ -, -CH=CHCH ₂ CH ₂ -, -CH ₂ CH=CHCH ₂ -, -OCH ₂ CH ₂ CH ₂ -, -CF=CF-CF=CF-, -C ≡C-, -C≡C-CF=CF-, -C≡C-CF=CF -C≡C-, -CF=CF-C≡C-CF=CF- or -C≡C-CF ₂ O-, and at least one of Z ₁ , Z ₂ , Z ₃ and Z ₄ is -OCH ₂ CF ₂ O- or -OCF ₂ CH ₂ O-; m, n and p are the same or different, each independently representing 0, 1 or 2, and m+n+p 1.

Another object of the present invention is to provide a liquid crystal composition comprising at least one liquid crystal compound having a (difluoro)ethylidene ether structure, which has good low-temperature mutual solubility and low birefringence, and A liquid crystal display element of a negative liquid crystal medium exhibits greater dielectric anisotropy and a lower driving voltage.

The effect of the present invention: the liquid crystal compound having the (difluoro)ethylenediether structure of the present invention has good chemical and physical stability, and has a low liquid crystal compound having no (difluoro)ethylene diether structure. Birefringence and greater dielectric anisotropy. The present invention also provides a liquid crystal composition comprising at least one of the above liquid crystal compounds. The liquid crystal composition has good low-temperature mutual solubility, small birefringence, larger dielectric anisotropy and lower driving voltage, and can be applied to liquid crystal elements containing liquid crystal compounds, and is particularly suitable for liquid crystal display of negative liquid crystal compounds. element.

The present invention is described in detail below. Preferably, R ₁ and R _{2 are the} same or different and each independently represents H, -F, -Cl, -CN, -NCS, , Unsubstituted C linear or branched alkyl group of ₁ to C _10, with at least one halogen-substituted straight-chain or branched C ₁ to C ₁₀ in the alkyl group, or a C ₁ to C ₁₀ alkoxy is group, wherein, in said R ₁ and R ₂ of said at least one -CH ₂ - may be -O -, - CH = CH - , - C≡ C -, - CF = CF -, - CH = CF- , Or -COO-substitution, provided that the heteroatoms are not directly connected to each other.

Preferably, the rings A ₁ , A ₂ , A ₃ , A ₄ and A _{5 are the} same or different and each independently represents , , And, the A ₁ and A ₅ can also represent or , the A ₅ can also represent R ⁴ or R ⁴ , wherein R ₃ and R ₄ are as defined for R ₁ and R ₂ .

Preferably, the rings A ₁ , A ₂ , A ₃ , A ₄ and A ₅ are each independently represented by , , , , , , or And the A ₁ can also represent or , the A ₅ can also represent R ⁴ or R ⁴ , wherein R ₃ and R ₄ are as defined for R ₁ and R ₂ .

Preferably, Z ₁ , Z ₂ , Z ₃ and Z _{4 are the} same or different and each independently represents -COO-, -CF ₂ O-, -CH ₂ O-, -OCH ₂ -, -CH ₂ CH ₂ - , -CF=CF-, -CH=CH-, -C ₂ F ₄ -, -(CH ₂ ) ₄ -, -(CF ₂ ) ₄ -, -OCF ₂ CF ₂ O-, -OCF ₂ CH ₂ O -, -OCH ₂ CF ₂ O-, -CH ₂ CH ₂ CF ₂ O-, -OCH ₂ CHFO-, -OCHFCH ₂ O-, -CF=CFCF ₂ O-, -C ₂ H ₄ OCH ₂ -, - OCH ₂ CH ₂ CH ₂ -, -C≡C- or a single bond, and at least one of Z ₁ , Z ₂ , Z ₃ and Z ₄ is -OCF ₂ CH ₂ O- or -OCH ₂ CF ₂ O-.

More preferably, Z ₁ , Z ₂ , Z ₃ and Z ₄ each independently represent -COO-, -CF ₂ O-, -CH ₂ O-, -CH ₂ CH ₂ -, -CF=CF-, -CH =CH-, -C ₂ F ₄ -, -(CH ₂ ) ₄ -, -(CF ₂ ) ₄ -, -OCF ₂ CF ₂ O-, -CH ₂ CH ₂ CF ₂ O-, -OCF ₂ CH ₂ O-, -OCH ₂ CF ₂ O-, -OCH ₂ CHFO-, -OCHFCH ₂ O-, -CF=CFCF ₂ O-, -C ₂ H ₄ OCH ₂ -, -OCH ₂ CH ₂ CH ₂ -, - C≡C- or a single bond, and at least one of Z ₁ , Z ₂ , Z ₃ and Z ₄ is -OCH ₂ CF ₂ O- or -OCF ₂ CH ₂ O-.

Still more preferably, Z ₁ , Z ₂ , Z ₃ and Z ₄ each independently represent -CF ₂ O-, -CH ₂ O-, -CH ₂ CH ₂ -, -CF=CF-, -CH=CH- , -OCF ₂ CH ₂ O-, -OCH ₂ CF ₂ O-, -C≡C- or a single bond, and at least one of Z ₁ , Z ₂ , Z ₃ and Z ₄ is -OCF ₂ CH ₂ O- Or -OCH ₂ CF ₂ O-.

Preferably, m, n and p are the same or different, each independently representing 0, 1 or 2, and 1 m+n+p 4.

The invention prepares liquid crystallination with (difluoro)ethylenediether structure The method of the composition comprises the following steps:

1) In a solvent of anhydrous dimethylformamide, under the protection of argon, add the compound of the formula (II-3), add sodium hydride in portions, raise the temperature to 60 ° C for 1 hour, cool to room temperature, and then Adding a solution of dimethylformamide containing ethyl difluorobromoacetate dropwise, and reacting at 60 ° C for 1 hour to obtain a compound of the formula (II-2);

2) The compound of the formula (II-2) is added in an anhydrous tetrahydrofuran under a nitrogen atmosphere at a temperature ranging from 0 ° C to 5 ° C in portions, and the mixture is allowed to react at room temperature for 2 hours to obtain a formula (II). a compound of -1);

3) The compound of the formula (II-1) is dissolved in anhydrous diisopropylamine, the temperature of the nitrogen is lowered to 0 ° C, and the reaction is carried out by adding trifluoromethanesulfonic anhydride or p-toluenesulfonyl chloride at 20 ° C to 25 ° C for 3 hours. a compound of the formula (II), wherein T is trifluoromethanesulfonyl or p-toluenesulfonyl;

4) In the anhydrous dimethylformamide solvent, under the protection of argon, add the compound of the formula (II), add sodium hydride in batches, raise the temperature to 90 ° C for 1 hour, cool to room temperature, then drop Adding a solution of the dimethylformamide containing the compound of the formula (III), and reacting at 60 ° C for 1 hour to obtain a compound of the formula (IV);

The compounds of the formula (II-3) and the formula (III) are mainly synthesized by a commercially available intermediate or a conventional synthesis method, wherein the conventional synthesis method includes an esterification reaction, a Witting reaction, and a carbon-carbon cross coupling. The reaction (Suzuki coupling, Negishi coupling, Heck coupling, Sonogashira coupling, and transition metal catalyzed Grignard reagent cross-coupling reaction, etc.), reduction reaction, and the like are obtained.

Preferably, the liquid crystal compound having a (difluoro)ethylene diether structure means: or Wherein R ₁ , R ₂ , R ₃ and R _{4 are} as defined above and will not be described again.

The present invention will be further illustrated by the following examples, but it should be understood that this embodiment is intended to be illustrative only and not to be construed as limiting.

For ease of expression, in the following examples, the group structure of the liquid crystal compound is represented by the codes listed in Table 1.

Take the following liquid crystal compound as an example: Expressed by the code listed in Table 1, it can be expressed as: 3PUQUF.

Example 1

The synthesis method of HCLC-11H is shown in the following figure, and the specific synthesis steps are as follows:

1) Synthesis of HCLC-11H-03

A 250 mL three-necked flask was charged with 6.54 g of 4-(propylcyclohexyl)phenol and dissolved in 180 mL of dimethyl decylamine (DMF). Under a nitrogen atmosphere, 2.04 g of NaH was added, followed by the slow addition of 7.92 g of difluorobromide. Ethyl acetate was added, and the mixture was heated to 60 ° C for 1 hour, and then acidified with dilute hydrochloric acid. 180 mL of water was added, and the mixture was extracted twice with ethyl acetate (180 mL), and the organic phase was combined and washed once with water (180 mL) to obtain an organic phase and an aqueous phase. The aqueous phase was extracted once with 180 mL of ethyl acetate. EtOAc was evaporated. . Theoretical yield 10.2 g, yield 74%, purity: 97.8%.

2) Synthesis of HCLC-11H-02

Dry a 250 mL three-necked flask, add 9.5 g of HCLC-11H-03 under nitrogen protection, and dissolve in 95 mL of THF to give a yellow reaction solution. The temperature was controlled at 0 ° C and dropped into 1.33 g of tetrahydrofuran (THF) suspension containing lithium aluminum hydride. The turbid liquid was added in 20 minutes, and the temperature was raised to room temperature (25 ± 3 ° C) for 2 hours. After the reaction, 100 mL of water was added, and ethyl acetate was added. After extracting 100 mL twice, the organic phase was combined, and then washed once with 100 mL of water to obtain an organic phase and an aqueous phase, respectively. The aqueous phase was extracted once with 100 mL of ethyl acetate. All organic phases were combined, washed twice with water, and then washed twice with brine, then dried and evaporated to give a crude product. 02. Theoretical yield 8.3 g, yield 93%, purity: 98.3%.

3) Synthesis of HCLC-11H-01

In a 250 mL three-necked flask, 2 g of HCLC-11H-02 and 100 mL of diisopropylamine were added, followed by cooling to 0 ° C using an ice salt bath, and 2 g of trifluoromethanesulfonic anhydride was added dropwise at 0 ° C, and the addition was completed in 10 minutes. The temperature was raised to between 10 ° C and 15 ° C for 2 hours. After the reaction, 100 ml of dichloromethane was added, and the mixture was washed three times with water, and washed three times with brine, and then dried and concentrated to give 2.7 g of crude product of HCLC-11H-01, purity: 93.5%.

4) Synthesis of HCLC-11H

In a 100 mL three-necked flask, 0.9 g of 3,4,5-trifluorophenol was added, and dissolved using 40 ml of DMF. Next, 0.53 g of NaH was added, and the mixture was heated to 60 ° C for 1 hour. After the reaction, the temperature was lowered to below 0 ° C, and 2.7 g of a DMF solution containing HCLC-11H-01 was added dropwise thereto. Next, the temperature was raised to room temperature (25 ± 3 ° C), and reacted at this temperature for 3 hours. After the reaction, 100 mL of water was added, and the mixture was extracted twice with 100 mL of ethyl acetate. The organic phase was combined and washed with water (100 mL) to obtain an organic phase and an aqueous phase. The aqueous phase was extracted once with 100 mL of ethyl acetate. The organics were combined and washed three times with water, three times with brine, and then dried and concentrated to give 3 g. Purified by petroleum ether column chromatography and concentrated to give 2.5 g of HCLC-11H, GC: 97.7% ( After recrystallization, a solid of 2.2 g, GC: 99.87%, yield 88%).

_{^{1 H NMR (300MHz, CDCl 3}} ) δ 7.65-7.26 (m, 2H), 7.10-6.57 (m, 4H), 4.92 (t, J = 41.8Hz, 2H), 2.60-2.26 (m, 1H), 2.02 -1.72 (m, 4H), 1.41 (dt, J = 15.4, 11.8 Hz, 2H), 1.35-1.10 (m, 5H), 1.03 (dt, J = 15.7, 11.7 Hz, 2H), 0.95-0.83 (m) , 3H).

Example 2

The synthesis method of HCLC-11J is shown in the figure below:

The synthesis method of HCLC-11J is synthesized according to the synthesis procedure of HCLC-11H, and trans-(1'-propyl-trans-4-cyclohexyl)cyclohexanol is used instead of 4-(propylcyclohexyl)phenol. The synthesis procedure of HCLC-11H-03, HCLC-11H-02 and HCLC-11H-01 gave HCLC-11J-01. The liquid crystal compound HCLC-11J can be obtained by a method of synthesizing HCLC-11J-01 and 2,3-difluoro-4-ethoxyphenol according to HCLC-11H.

¹ H NMR (300MHz, CDCl ₃ ) δ 6.79-6.54 (m, 2H), 4.83 (t, J = 41.7 Hz, 2H), 4.05 (q, J = 11.8 Hz, 2H), 3.73-3.59 (m, 1H) ), 1.93 (dt, J = 14.5, 11.8 Hz, 2H), 1.86-1.74 (m, 6H), 1.50-0.99 (m, 18H), 0.94-0.78 (m, 3H).

Example 3

The synthesis method of HCLC-11M is shown in the following figure:

Referring to the synthesis method of HCLC-11H, the liquid crystal compound HCLC-11M can be prepared by reacting 2,3-difluoro-4-ethoxy phenol with 3,4,5-trifluorophenol and reacting with HCLC-11J-01. .

_{^{1 H NMR (300MHz, CDCl 3}} ) δ 7.50-7.21 (m, 2H), 7.04-6.73 (m, 2H), 6.77-6.57 (m, 2H), 5.01 (t, J = 41.7Hz, 2H), 4.05 (q, J = 11.8 Hz, 2H), 2.53 - 2.28 (m, 1H), 1.91 (dt, J = 15.0, 11.6 Hz, 2H), 1.79 (dt, J = 15.5, 11.6 Hz, 2H), 1.51 1.11 (m, 10H), 1.02 (dt, J = 15.7, 11.7 Hz, 2H), 0.93-0.82 (m, 3H).

Example 4

The synthesis method of HCLC-15 is shown in the following figure, and the specific synthesis steps are as follows:

1) Synthesis of HCLC-15-03

250 mL three-necked flask, 3.72 g of p-methoxyphenol was added, and dissolved in 150 mL of DMF, 2.04 g of NaH was added under nitrogen atmosphere, and then the temperature was raised to 60 ° C for 1 hour, and then 7.92 g of difluorobromoacetic acid B was slowly added. The ester was reacted to 25 ° C for 3 hours, followed by acidification with dilute hydrochloric acid. 180 mL of water was added, and the mixture was extracted twice with 180 mL of ethyl acetate. The organic phase was combined and washed with water (180 mL) to obtain an organic phase and an aqueous phase. The aqueous phase was extracted once with 180 mL of ethyl acetate. EtOAc was evaporated. It was purified by column chromatography on petroleum ether and concentrated to give 5.6 g of HCLC-15-03. Purity: 95.25%, yield 75.9%.

2) Synthesis of HCLC-15-02

A dry 250 mL three-necked flask was added to HCLC-15-03 under nitrogen atmosphere and dissolved in THF to give a colorless reaction mixture. The temperature was controlled at 0 ° C, and a suspension of THF containing lithium aluminum hydride was added dropwise thereto at this temperature. After the addition was completed for 20 minutes, the temperature was raised to 15 ° C and reacted at the temperature for 12 hours, after which water was added. 100 mL and extracted twice with 100 mL of ethyl acetate. The organic phases were combined and washed once with 100 mL of water to obtain an organic phase and an aqueous phase. The aqueous phase was extracted once with 100 mL of ethyl acetate. EtOAc was evaporated and evaporated. The theoretical yield was 3.65 g, the yield was 95.7%, and the purity was 98.91%.

3) Synthesis of HCLC-15-01

In a 250 mL three-necked flask, add HCLC-15-02 and use dichloro Methane was dissolved, followed by the addition of diisopropylamine. The temperature was lowered to -10 ° C using an ice salt bath, the temperature was controlled below 0 ° C, trifluoromethanesulfonic anhydride was added dropwise, and after completion of the addition for 10 minutes, the reaction was carried out at 25 ° C for 1 hour. Subsequently, it was washed three times with water, three times with brine, and then dried and concentrated to give a crude product of 4.5 g of HCLC-15-01, purity: 95.7%.

4) Synthesis of HCLC-15

In a 250 mL three-necked flask, 4-(propylcyclohexyl)benzene was added and dissolved in DMF. After that, NaH was added, and the temperature was lowered to 0 °C using an ice salt bath, and the temperature was lowered to 0 °C to contain HCLC-15-01. The DMF solution was reacted at room temperature for 3 hours. Next, 100 mL of water was added, and the mixture was extracted twice with 100 mL of ethyl acetate. The organic phases were combined and washed once with 100 mL of water to obtain an organic phase and an aqueous phase. The aqueous phase was extracted once with 100 mL of ethyl acetate. EtOAc was evaporated. Purification by petroleum ether column chromatography, concentrated and dried to give 4.1 g of HCLC-15, purity: 98.57%, and then recrystallized from petroleum ether to give a solid 3.9 g, purity: 99.6%, yield 86.7%.

_{^{1 H NMR (300MHz, CDCl 3}} ) δ 7.51-7.28 (m, 2H), 7.11-6.94 (m, 2H), 6.93-6.71 (m, 4H), 4.88 (t, J = 41.9Hz, 2H), 3.79 (s, 3H), 2.58-2.27 (m, 1H), 1.98-1.74 (m, 4H), 1.48-1.34 (m, 2H), 1.34-1.11 (m, 5H), 1.03 (dt, J = 15.7, 11.7 Hz, 2H), 0.96-0.83 (m, 3H).

The following Examples 5-6 are performance tests of the liquid crystal compositions of the present invention, and each case has a corresponding comparative example: the abbreviated code of the test items in the following examples is as follows: Cp (°C): Clarification point (nematic-isotropic phase) Transition temperature); η (mPa.s): flow viscosity (measured at 20 ° C); Δn: optical anisotropy (589 nm, 20 ° C); Δ ε: dielectric anisotropy (1 kHz, 25 ° C); Vth (V ): Threshold voltage (1 kHz, 25 ° C).

Example 5

The liquid crystal composition was prepared according to each liquid crystal compound and weight percentage listed in Table 2, and the performance test was performed. The test data is as shown in Table 2 below:

Example 6

The liquid crystal compositions were prepared according to the respective liquid crystal compounds and weight percentages listed in Table 3, and performance tests were performed. The test data are shown in Table 3 below:

Comparative example 7

The liquid crystal composition was prepared according to each liquid crystal compound listed in Table 4 and the weight percentage, and the performance test was performed. The test data is shown in the following table:

Referring to Comparative Example 7, it can be seen from the test data of Examples 5 and 6 above that the liquid crystal composition of the present invention using a liquid crystal compound having a (difluoro)ethylenediether structure has a smaller birefringence and a larger dielectric. Anisotropy and lower drive voltage.

In summary, the liquid crystal compound having (difluoro)ethylenediether of the present invention has good chemical and physical stability and has a low liquid crystal compound having no (difluoro)ethylenediether structure. Birefringence, and has more Large dielectric anisotropy. The present invention also provides a liquid crystal composition comprising at least one of the above liquid crystal compounds. The liquid crystal composition has good low-temperature mutual solubility, small birefringence, larger dielectric anisotropy and lower driving voltage, and can be applied to a liquid crystal element containing a liquid crystal medium, and is particularly suitable for liquid crystal of a negative liquid crystal medium. The elements are shown so that the object of the invention can be achieved.

The above is only the preferred embodiment of the present invention, and the scope of the present invention is not limited thereto, that is, the simple equivalent changes and modifications made by the patent application scope and patent specification content of the present invention, All remain within the scope of the invention patent.

Claims (10)

A liquid crystal compound having a (difluoro)ethylenediether structure, represented by the general formula (I): Wherein R ₁ and R ₂ each independently represent -H, -F, -Cl, -CN, -NCS, -SCN, -OCN, -NCO, , Unsubstituted C linear or branched alkyl group of ₁ to C ₂₀ straight-chain or branched-chain alkyl group with at least one halogen-substituted C ₁ to C ₂₀ or C ₁ to C ₂₀ alkoxy is a base, wherein when R ¹ and R ² are , C unsubstituted straight or branched chain alkyl group of ₂ to C _20, with at least one halogen-substituted C linear or branched alkyl group of ₂ to C _20, or C ₂ to C ₂₀ alkoxy is At least one -CH ₂ - may be -O-, -S-, -SiH ₂ -, -CH=CH-, -C≡C-, -CF=CF-, -CH=CF-, , -COO- or -OCO-substitution, provided that the heteroatoms are not directly bonded to each other; the rings A ₁ , A ₂ , A ₃ , A ₄ and A _{5 are the} same or different, each independently representing a cyclic structure, and the ring Structural representation , or Wherein the cyclic structure may also conform to at least one of the following a), b), c) and d): a) one or more hydrogen atoms in the cyclic structure may be -D, -F , -Cl, -CN, -CF ₃ , -OCF ₃ , -CH ₂ F, -OCH ₂ F, -CF ₂ H, -OCF ₂ H, -OCH ₃ or -CH ₃ substitution; b) the ring One or more -CH ₂ - in the structure is substituted by -O-, -SiH ₂ -, -S- or -CO-, provided that the heteroatoms are not directly linked to each other; c) in the cyclic structure, One or more -CH- in the ring structure may be substituted by -N-; d) one or more of the ring structures Can be Substituting; and, the A ₁ can also represent , , or , the A ₅ can also represent , , or Wherein R ₃ and R ₄ are as defined for R ₁ and R ₂ ; Z ₁ , Z ₂ , Z ₃ and Z _{4 are the} same or different and each independently represents a single bond, -COO-, -CF ₂ O-, -CH ₂ O-, -OCH ₂ -, -CH ₂ CH ₂ -, -CF ₂ CH ₂ -, -CF=CF-, -CH=CH-, -CH=CF-, -C ₂ F ₄ -, -(CH ₂ ) ₄ -, -(CF ₂ ) ₄ -, -OCF ₂ CF ₂ O-, -CF ₂ CF ₂ CF ₂ O-, -CH ₂ CH ₂ CF ₂ O-, -OCH ₂ CF ₂ O -, -OCF ₂ CH ₂ O-, -CH ₂ CF ₂ OCH ₂ -, -CH=CHCF ₂ O-, -CF ₂ OCH=CH-, -CF ₂ OCF=CH-, -CF ₂ OCH=CF- , -CF=CFCF ₂ O-, -CF ₂ OCF=CF-, -C ₂ H ₄ OCH ₂ -, -CH=CHCH ₂ CH ₂ -, -OCH ₂ CHFO-, -OCHFCH ₂ O-, -CH ₂ CH=CHCH ₂ -, -OCH ₂ CH ₂ CH ₂ -, -CF=CF-CF=CF-, -C≡C-CF=CF-, -C≡C-CF=CF-C≡C-,- C≡C-, -CF=CF-C≡C-CF=CF- or -C≡C-CF ₂ O-, and at least one of Z ₁ , Z ₂ , Z ₃ and Z ₄ is -OCH ₂ CF ₂ O- or -OCF ₂ CH ₂ O-; m, n and p are the same or different, each independently representing 0, 1 or 2, and m+n+p 1. The liquid crystal compound having a (difluoro)ethylenediether structure according to claim 1, wherein R ₁ and R _{2 are the} same or different and each independently represents -H, -F, -Cl, -CN, -NCS, , Unsubstituted C linear or branched alkyl group of ₁ to C _10, with at least one halogen-substituted straight-chain or branched C ₁ to C ₁₀ in the alkyl group, or a C ₁ to C ₁₀ alkoxy is a base, wherein when R ¹ and R ² are , C unsubstituted straight or branched chain alkyl group of ₂ to C _20, with at least one halogen-substituted C linear or branched alkyl group of ₂ to C _20, or C ₂ to C ₂₀ alkoxy is At least one -CH ₂ - may be -O-, -CH=CH-, -C≡C-, -CF=CF-, -CH=CF-, Or -COO-substitution, provided that the heteroatoms are not directly attached to each other. The liquid crystal compound having a (difluoro)ethylidene ether structure as described in claim 1, wherein the rings A ₁ , A ₂ , A ₃ , A ₄ and A _{5 are the} same or different and each independently represents , , , And, the A ₁ and A ₅ can also represent or , the A ₅ can also represent or Wherein R ₃ and R ₄ are as defined for R ₁ and R ₂ . A liquid crystal compound having a (difluoro)ethylenediether structure as claimed in claim 3, wherein the rings A ₁ , A ₂ , A ₃ , A ₄ and A ₅ are each independently represented or And the A ₁ can also represent or , the A ₅ can also represent or Wherein R ₃ and R ₄ are as defined for R ₁ and R ₂ . A liquid crystal compound having a (difluoro)ethylidene ether structure as claimed in claim 1, wherein Z ₁ , Z ₂ , Z ₃ and Z _{4 are the} same or different and each independently represents -COO-, -CF ₂ O -, -CH ₂ O-, -OCH ₂ -, -CH ₂ CH ₂ -, -CF=CF-, -CH=CH-, -C ₂ F ₄ -, -(CH ₂ ) ₄ -, -(CF ₂ ) ₄ -, -OCF ₂ CF ₂ O-, -OCF ₂ CH ₂ O-, -OCH ₂ CF ₂ O-, -OCH ₂ CHFO-, -OCHFCH ₂ O-, -CH ₂ CH ₂ CF ₂ O- , -CF=CFCF ₂ O-, -C ₂ H ₄ OCH ₂ -, -OCH ₂ CH ₂ CH ₂ -, -C≡C- or a single bond, and at least Z ₁ , Z ₂ , Z ₃ and Z ₄ One is -OCF ₂ CH ₂ O- or -OCH ₂ CF ₂ O-. A liquid crystal compound having a (difluoro)ethylidene ether structure as claimed in claim 5, wherein Z ₁ , Z ₂ , Z ₃ and Z ₄ each independently represent -COO-, -CF ₂ O-, -CH ₂ O-, -CH ₂ CH ₂ -, -CF=CF-, -CH=CH-, -C ₂ F ₄ -, -(CH ₂ ) ₄ -, -(CF ₂ ) ₄ -, -OCF ₂ CF ₂ O-, -CH ₂ CH ₂ CF ₂ O-, -OCF ₂ CH ₂ O-, -OCH ₂ CF ₂ O-, -OCH ₂ CHFO-, -OCHFCH ₂ O-, -CF=CFCF ₂ O-, -C ₂ H ₄ OCH ₂ -, -OCH ₂ CH ₂ CH ₂ -, -C≡C- or a single bond, and at least one of Z ₁ , Z ₂ , Z ₃ and Z ₄ is -OCH ₂ CF ₂ O -or-OCF ₂ CH ₂ O-. The requested item 6 has the (difluoro-yl) ethylene ether structure of the liquid crystal compound, _{wherein, Z 1, Z 2, Z} 3 and Z ₄ each independently represents _{-CF 2 O -, - CH 2} O-, -CH ₂ CH ₂ -, -CF=CF-, -CH=CH-, -OCF ₂ CH ₂ O-, -OCH ₂ CF ₂ O-, -C≡C- or a single bond, and Z ₁ , Z ₂ At least one of Z ₃ and Z ₄ is -OCF ₂ CH ₂ O- or -OCH ₂ CF ₂ O-. A liquid crystal compound having a (difluoro)ethylenediether structure as claimed in claim 1, wherein m, n and p are the same or different and each independently represents 0, 1, or 2, and 1 m+n+p 4. A liquid crystal compound having a (difluoro)ethylenediether structure as claimed in claim 1, wherein the liquid crystal having a (difluoro)ethylenediether structure represents: A liquid crystal composition comprising at least one liquid crystal compound having a (difluoro)ethylenediether structure according to any one of claims 1 to 9.