Liquid crystal compound and method for synthesizing the same

Abstract

The present application provides a liquid crystal compound and a synthesis method thereof, which is applied to a liquid crystal composition, can greatly improve the low-temperature storage performance of the liquid crystal composition, and can also accelerate the recovery time of the liquid crystal composition.

Description

Technical Field

[0001] This invention belongs to the field of liquid crystal materials and relates to a liquid crystal compound and its synthesis method. Background Technology

[0002] Compared to traditional display devices and materials, liquid crystal display (LCD) materials have significant advantages: low driving voltage, minimal power consumption, high reliability, large display information capacity, color display, flicker-free operation, no harm to the human body, automated production process, low cost, and the ability to be manufactured into various specifications and types of LCD displays, making them portable. Due to these advantages, LCD technology has profoundly impacted the field of display imaging, promoting the development of microelectronics and optoelectronic information technology. Liquid crystal materials, with their excellent optical properties and photoelectric effects, have found widespread application in numerous display scenarios.

[0003] Liquid crystals are primarily used as dielectrics in display devices because their optical properties can be altered by applying voltage. Liquid crystal materials must possess good chemical and thermal stability, as well as good stability to electric fields and electromagnetic radiation. Furthermore, industrially usable liquid crystal phases require a mesocrystalline phase within a suitable temperature range and low viscosity.

[0004] Since liquid crystals are typically used as mixtures of multiple components, it is important that these components are easily miscible with each other. Other properties, such as response speed, dielectric anisotropy, and optical anisotropy, must meet various requirements depending on the type of liquid crystal cell and the application.

[0005] The low-temperature storage performance of existing liquid crystal compositions is relatively poor. Crystallization will occur after about 15 days of storage in a liquid crystal cell at -30°C, which cannot meet the continuous use requirements of low-temperature equipment. Summary of the Invention

[0006] To address the aforementioned technical problems, this application provides a liquid crystal compound that, when applied to a liquid crystal composition, can significantly improve the low-temperature storage performance of the liquid crystal composition and accelerate its recovery time.

[0007] To achieve the above-mentioned technical effects, the present invention adopts the following technical solution:

[0008] One objective of this invention is to provide a liquid crystal compound, the structure of which is shown in the following formula:

[0009]

[0010] Where M is any one of -R, -G1-R or -G1-G2-R, G1 and G2 are independently any one of substituted or unsubstituted cyclopentyl, cyclohexyl or phenyl, R is a hydrocarbon group or hydrocarbon oxygen group, Y is any substituent that satisfies its chemical environment, and n is an integer from 0 to 5.

[0011] As a preferred embodiment of the present invention, R is a C1-12 alkyl, C1-12 alkoxy, C2-12 alkenyl, or C2-12 alkenoxy.

[0012] As a preferred embodiment of the present invention, Y is -F, -OCF3, -CF3, an unsubstituted alkenyl group of C2 to 6, an unsubstituted alkenyl group of C2 to 6, an alkenyl group of C2 to 6 containing at least one -F substituent, or an alkenyl group of C2 to 6 containing at least one -F substituent.

[0013] As a preferred embodiment of the present invention, the liquid crystal compound includes...

[0014]

[0015]

[0016] Any one of them.

[0017] A second objective of this invention is to provide a method for synthesizing the liquid crystal compound provided in the first objective, the method being as follows:

[0018]

[0019] Where X is any one of Cl, Br or I.

[0020] As a preferred technical solution of the present invention, the synthesis includes the following steps:

[0021] Under a protective atmosphere, compound A, compound B and a first organic solvent are mixed, and a first catalyst is added to react and obtain compound C;

[0022] Compound C, compound D, a second catalyst, a base, water, and a second organic solvent were mixed and reacted under a protective atmosphere to obtain compound P.

[0023] As a preferred embodiment of the present invention, the first organic solvent includes any one or a combination of at least two of toluene, dichlorohexane, petroleum ether, n-heptane, or n-hexane.

[0024] And / or, the first catalyst comprises any one or a combination of at least two of toluenesulfonic acid, p-toluenesulfonic acid pyridinium salt, or a solid acid catalyst.

[0025] As a preferred technical solution of the present invention, the reaction temperature for synthesizing compound C is 40-110°C and the time is 1-10h.

[0026] As a preferred embodiment of the present invention, the second organic solvent includes any one or a combination of at least two of toluene, ethanol, tetrahydrofuran, 2-methyltetrahydrofuran, 1,4-dioxane or methyl tert-butyl ether.

[0027] And / or, the base includes any one or a combination of at least two of sodium carbonate, potassium carbonate, cesium carbonate, sodium hydroxide, potassium hydroxide, lithium hydroxide, potassium tert-butoxide, or sodium tert-butoxide.

[0028] And / or, the second catalyst comprises any one or a combination of at least two of the following: bis(dibenzylacetone)palladium, tetra(triphenylphosphine)palladium dichloride, bis(triphenylphosphine)palladium dichloride, dichloroditert-butyl-(4-dimethylaminophenyl)phosphine palladium, or 1,1'-bis(diphenylphosphine)ferrocene palladium dichloride.

[0029] As a preferred technical solution of the present invention, the temperature for the synthesis reaction of compound P is 60-110℃ and the time is 1-10h.

[0030] Compared with the prior art, the present invention has at least the following beneficial effects:

[0031] (1) This application provides a liquid crystal compound, which can significantly improve the low-temperature storage performance of the liquid crystal composition when applied to a liquid crystal composition, and the storage time at -30°C can be more than 500 hours.

[0032] (2) This application provides a liquid crystal compound that, when applied to a liquid crystal composition, can accelerate the recovery time of the liquid crystal composition, τ off It can be as fast as 6.8 seconds. Detailed Implementation

[0033] The technical solution of this application will be further described below through specific implementation methods.

[0034] This invention provides a liquid crystal compound, the structure of which is shown in the following formula:

[0035]

[0036] Where M is any one of -R, -G1-R, or -G1-G2-R, G1 and G2 are independently any one of substituted or unsubstituted cyclopentyl, cyclohexyl, or phenyl, R is a hydrocarbon group or hydroxyl group, Y is any substituent that satisfies its chemical environment, and n is an integer from 0 to 5. Wherein, n can be 1, 2, 3, 4, or 5.

[0037] In one specific embodiment of the present invention, R is a C1-12 alkyl, C1-12 alkoxy, C2-12 alkenyl, or C2-12 alkenoxy.

[0038] In one specific embodiment of the present invention, R can be methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, n-pentyl, n-hexyl, and n-dodecyl, etc.

[0039] In one specific embodiment of the present invention, R can be methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, n-pentoxy, n-hexoxy, and n-dodecyloxy, etc.

[0040] In one specific embodiment of the present invention, R can be vinyl, n-propenyl, isopropenyl, n-butenyl, isobutenyl, n-pentenyl, n-hexenyl, and n-dodecenyl, etc.

[0041] In one specific embodiment of the present invention, R can be ethyleneoxy, n-propyleneoxy, isopropyleneoxy, n-butenoxy, isobutenoxy, n-pentenoxy, n-hexenoxy, and n-dodecenoxy, etc.

[0042] In one specific embodiment of the present invention, Y is -F, -OCF3, -CF3, an unsubstituted alkenyl group of C2 to 6, an unsubstituted alkenyl group of C2 to 6, an alkenyl group of C2 to 6 containing at least one -F substituent, or an alkenyl group of C2 to 6 containing at least one -F substituent.

[0043] In one specific embodiment of the present invention, Y can be vinyl, n-propenyl, isopropenyl, n-butenyl, isobutenyl, n-pentenyl, and n-hexenyl, etc.

[0044] In one specific embodiment of the present invention, Y can be ethyleneoxy, n-propyleneoxy, isopropyleneoxy, n-butenoxy, isobutenoxy, n-pentenoxy, and n-hexenoxy, etc.

[0045] In one specific embodiment of the present invention, Y can be a vinyl, propenyl, isopropenyl, n-butenyl, isobutenyl, n-pentenyl, and n-hexenyl group containing at least one -F substituent, such as 2,2-difluorovinyl, trifluorovinyl, etc.

[0046] In one specific embodiment of the present invention, Y can be an ethoxy group containing at least one -F substituent, such as 2,2-difluoroethoxy, trifluoroethoxy, etc.

[0047] In one specific embodiment of the present invention, the liquid crystal compound includes

[0048]

[0049] Any one of them.

[0050] This invention provides a method for synthesizing a liquid crystal compound, as shown in the following formula:

[0051]

[0052] Where X is any one of Cl, Br or I.

[0053] In one specific embodiment of the present invention, the synthesis includes the following steps:

[0054] Under a protective atmosphere, compound A, compound B and a first organic solvent are mixed, and a first catalyst is added to react and obtain compound C;

[0055] Compound C, compound D, a second catalyst, a base, water, and a second organic solvent were mixed and reacted under a protective atmosphere to obtain compound P.

[0056] In one specific embodiment of the present invention, the first organic solvent includes any one or a combination of at least two of toluene, dichlorohexane, petroleum ether, n-heptane, or n-hexane. Preferably, it is toluene, dichlorohexane, and n-heptane.

[0057] In one specific embodiment of the present invention, the first catalyst comprises any one or a combination of at least two of toluenesulfonic acid, p-toluenesulfonic acid pyridinium salt, or a solid acid catalyst. Preferably, it comprises p-toluenesulfonic acid and a solid acid catalyst.

[0058] In one specific embodiment of the present invention, the solid acid catalyst includes HND-8, HND-583, HND-63, and HND-582.

[0059] In one specific embodiment of the present invention, compound A and compound B can be added according to the stoichiometric ratio of the chemical reaction equation, or adjusted according to the stoichiometric ratio based on the reaction situation, without specific limitations.

[0060] In one specific embodiment of the present invention, in the reaction for synthesizing compound C, the amount of catalyst added can be adjusted according to the reaction conditions to effectively improve the reaction rate of the reaction for synthesizing compound C, and no specific limitation is made here.

[0061] In one specific embodiment of the present invention, in the reaction for synthesizing compound C, the amount of solvent added can be adjusted according to the reaction situation when dissolving compounds A and B, and is not specifically limited here.

[0062] In one specific embodiment of the present invention, the reaction temperature for synthesizing compound C is 40–110°C, and the time is 1–10 h. The temperature can be 40°C, 50°C, 60°C, 70°C, 80°C, 90°C, 100°C, or 110°C, etc., and the time can be 1 h, 2 h, 3 h, 4 h, 5 h, 6 h, 7 h, 8 h, 9 h, or 10 h, etc., but is not limited to the listed values; other unlisted values ​​within the above ranges are also applicable.

[0063] In one specific embodiment of the present invention, after the reaction for synthesizing compound C is completed, the product is purified by means of filtration, column separation and washing to obtain pure compound C product.

[0064] In one specific embodiment of the present invention, the second organic solvent comprises any one or a combination of at least two of toluene, ethanol, tetrahydrofuran, 2-methyltetrahydrofuran, 1,4-dioxane, or methyl tert-butyl ether. Preferably, it comprises toluene, ethanol, tetrahydrofuran, and 1,4-dioxane.

[0065] In one specific embodiment of the present invention, the alkali includes any one or a combination of at least two of sodium carbonate, potassium carbonate, cesium carbonate, sodium hydroxide, potassium hydroxide, lithium hydroxide, potassium tert-butoxide, or sodium tert-butoxide. Preferably, it includes cesium carbonate, sodium hydroxide, potassium hydroxide, and potassium tert-butoxide.

[0066] In one specific embodiment of the present invention, the second catalyst comprises any one or a combination of at least two of the following: bis(dibenzylacetone)palladium, tetra(triphenylphosphine)palladium dichloride, bis(triphenylphosphine)palladium dichloride, dichlorodi-tert-butyl-(4-dimethylaminophenyl)phosphine palladium, or 1,1'-bis(diphenylphosphine)ferrocene palladium dichloride. Preferably, it comprises tetra(triphenylphosphine)palladium dichloride, bis(triphenylphosphine)palladium dichloride, and dichlorodi-tert-butyl-(4-dimethylaminophenyl)phosphine palladium.

[0067] In one specific embodiment of the present invention, compounds C and D can be added according to the stoichiometric ratio of the chemical reaction equation, or adjusted according to the stoichiometric ratio based on the reaction conditions, without specific limitations.

[0068] In one specific embodiment of the present invention, in the reaction for synthesizing compound P, the amount of alkali added can be adjusted according to the reaction conditions while maintaining the alkaline environment of the reaction, and no specific limitation is made here.

[0069] In one specific embodiment of the present invention, in the reaction for synthesizing compound P, the amount of water and organic solvent added can be adjusted according to the reaction conditions when dissolving compounds C and D, and no specific limitation is made here.

[0070] In one specific embodiment of the present invention, in the reaction for synthesizing compound P, the amount of catalyst added can be adjusted according to the reaction conditions to effectively improve the reaction rate of the reaction for synthesizing compound P, and no specific limitation is made here.

[0071] In one specific embodiment of the present invention, the reaction temperature for synthesizing compound P is 60–110°C, and the time is 1–10 h. The temperature can be 60°C, 70°C, 80°C, 90°C, 100°C, or 110°C, etc., and the time can be 1 h, 2 h, 3 h, 4 h, 5 h, 6 h, 7 h, 8 h, 9 h, or 10 h, etc., but is not limited to the listed values; other unlisted values ​​within the above ranges are also applicable.

[0072] In one specific embodiment of the present invention, after the reaction of the synthetic compound P is completed, the product is purified by means of filtration, washing and pulping to obtain pure compound P.

[0073] In one specific embodiment of the present invention, the protective atmosphere includes nitrogen, helium, or argon, preferably nitrogen. Specifically, before adding the reaction raw materials, nitrogen is introduced into the reaction apparatus to replace the air therein.

[0074] To facilitate understanding of the present invention, the following embodiments are provided. Those skilled in the art should understand that these embodiments are merely illustrative and should not be construed as limiting the scope of the invention.

[0075] Example 1

[0076] This embodiment provides a method for synthesizing a liquid crystal compound, the method comprising:

[0077]

[0078] Compound A-1 (60 g, 0.3 mol), compound B-1 (50 g, 0.3 mol), a solid acid catalyst (0.18 g), and 300 mL of dichloromethane were added sequentially to a 1 L three-necked flask. The mixture was refluxed at 50 °C for 8 h under nitrogen protection. After the reaction was complete, the reaction solution was filtered to recover the solid acid catalyst. The filtrate was concentrated by column chromatography, and the residue was slurried twice with 300 mL of ethanol to obtain 96 g of white solid (compound C-1), with a GC purity of 99.2% and a yield of 91.5%.

[0079] m / z: 348.19 (100.0%), 350.18 (32.0%), 349.19 (23.1%), 351.19 (7.5%), 350.19 (2.9%).

[0080]

[0081] In a 1L three-necked flask, compound C-1 (96 g, 0.28 mol), compound D-1 (51 g, 0.29 mol), dichlorodi-tert-butyl-(4-dimethylaminophenyl)phosphine palladium (0.19 g, 0.28 mmol), X-Phos (0.262 g, 0.55 mmol), potassium tert-butoxide (61.8 g, 0.55 mol), 500 mL of 1,4-dioxane, and 100 mL of water were added sequentially. The mixture was refluxed at 95 °C for 7 h under nitrogen protection. After the reaction was complete, 500 mL of water was added to slurry the mixture. The mixture was filtered, and the filter cake was washed with water until neutral. Then, it was slurried twice with 200 mL of ethanol to obtain 117.5 g of white solid (compound P-1), with an HPLC purity of 99.9% and a yield of 96%.

[0082] m / z: 444.23 (100.0%), 445.23 (29.6%), 446.23 (4.5%).

[0083] Example 2

[0084] This embodiment provides a method for synthesizing a liquid crystal compound, the method comprising:

[0085]

[0086] Compound A-2 (50 g, 0.22 mol), compound B-2 (46.2 g, 0.22 mol), a solid acid catalyst (0.15 g), and 250 mL of dichloromethane were added sequentially to a 1 L three-necked flask. The mixture was refluxed at 50 °C for 8 h under nitrogen protection. After the reaction was complete, the solid acid catalyst was recovered by filtration. The filtrate was concentrated by column chromatography, and the residue was slurried twice with 250 mL of ethanol to give 75 g of white solid (compound C-2), with a GC purity of 99.6% and a yield of 90.4%.

[0087] m / z: 376.22 (100.0%), 378.21 (32.0%), 377.22 (25.3%), 379.22 (8.2%), 378.22 (3.4%), 380.22 (1.1%).

[0088]

[0089] In a 1L three-necked flask, compound C-2 (75g, 0.18mol), compound D-1 (33g, 0.19mol), dichlorodi-tert-butyl-(4-dimethylaminophenyl)phosphine palladium (0.063g, 0.09mmol), potassium carbonate (50g, 0.36mol), 350mL toluene, 100mL ethanol, and 100mL water were added sequentially. The mixture was refluxed at 95°C for 6 hours under nitrogen protection. After the reaction was complete, 350mL of water was added to slurry the mixture, which was then filtered. The filter cake was washed with water until neutral and then slurried twice with 150mL of ethanol to obtain 80.3g of white solid (compound P-2), with an HPLC purity of 99.9% and a yield of 95.5%.

[0090] m / z: 472.26 (100.0%), 473.26 (31.4%), 474.27 (4.9%).

[0091] Example 3

[0092] This embodiment provides a method for synthesizing a liquid crystal compound, the method comprising:

[0093]

[0094] In a 1L three-necked flask, compound C-1 (40 g, 0.115 mol), compound D-1 (21.2 g, 0.12 mol), dichlorodi-tert-butyl-(4-dimethylaminophenyl)phosphine palladium (0.081 g, 0.115 mmol), X-Phos (0.109 g, 0.23 mmol), potassium tert-butoxide (25.8 g, 0.23 mol), 200 mL of 1,4-dioxane, and 40 mL of water were added sequentially. The mixture was refluxed at 95 °C for 7 h under nitrogen protection. After the reaction was complete, 200 mL of water was added to slurry the mixture. The mixture was filtered, and the filter cake was washed with water until neutral. Then, it was slurryed twice with 100 mL of ethanol to obtain 47.6 g of white solid (compound P-3), with an HPLC purity of 99.9% and a yield of 97.3%.

[0095] m / z: 426.24 (100.0%), 427.24 (29.6%), 428.24 (4.5%).

[0096] Example 4

[0097] This embodiment provides a method for synthesizing a liquid crystal compound, the method comprising:

[0098]

[0099] In a 1L three-necked flask, compound A-3 (20g, 0.066mol), compound B-1 (11g, 0.066mol), a solid acid catalyst (0.06g), and 100mL of dichloromethane were added sequentially. The mixture was refluxed at 50°C for 8 hours under nitrogen protection. After the reaction was complete, the reaction solution was filtered to recover the solid acid catalyst. The filtrate was concentrated by column chromatography, and the residue was slurried twice with 100mL of ethanol to obtain 27g of white solid (compound C-3), with a GC purity of 99.1% and a yield of 91%.

[0100] m / z: 452.25 (100.0%), 454.25 (37.1%), 453.25 (31.9%), 455.25 (10.2%), 456.25 (1.7%).

[0101]

[0102] In a 1L three-necked flask, compound C-3 (27 g, 0.06 mol), compound D-1 (11 g, 0.062 mol), dichlorodi-tert-butyl-(4-dimethylaminophenyl)phosphine palladium (0.042 g, 0.06 mmol), X-Phos (0.057 g, 0.12 mmol), potassium tert-butoxide (13.4 g, 0.12 mol), 150 mL of 1,4-dioxane, and 30 mL of water were added sequentially. The mixture was refluxed at 95 °C for 7 h under nitrogen protection. After the reaction was complete, 150 mL of water was added to slurry the mixture. The mixture was filtered, and the filter cake was washed with water until neutral. Then, it was slurried twice with 60 mL of ethanol to obtain 30.9 g of white solid (compound P-4), with an HPLC purity of 99.9% and a yield of 94.6%.

[0103] m / z: 548.29 (100.0%), 549.29 (37.9%), 550.30 (7.2%), 551.30 (1.0%).

[0104] Application Example 1

[0105] This application example provides a liquid crystal composition comprising liquid crystal compound P-1 synthesized in Example 1. The composition and performance test results of the liquid crystal composition are shown in Table 1.

[0106] Table 1

[0107]

[0108] Application Example 2

[0109] This application example provides a liquid crystal composition comprising the liquid crystal compound P-2 synthesized in Example 2. The composition and performance test results of the liquid crystal composition are shown in Table 2.

[0110] Table 2

[0111]

[0112] Application Example 3

[0113] This application example provides a liquid crystal composition comprising the liquid crystal compound P-3 synthesized in Example 3. The composition and performance test results of the liquid crystal composition are shown in Table 3.

[0114] Table 3

[0115]

[0116]

[0117] Application Example 4

[0118] This application example provides a liquid crystal composition comprising the liquid crystal compound P-4 synthesized in Example 4. The composition and performance test results of the liquid crystal composition are shown in Table 4.

[0119] Table 4

[0120]

[0121] Comparative Application Example 1

[0122] In this comparative application example, except that liquid crystal compound P-1 was not added, and the content percentages of 3CDPUF and 2DCPUF were 6.5%, all other conditions were the same as in application example 1. The τ of this liquid crystal composition was measured. off It is 9.6, t -30℃ For >200h.

[0123] Comparative Application Example 2

[0124] In this comparative application example, except that liquid crystal compound P-2 was not added, and the content percentages of 3CDPUF and 2DCPUF were 4.5%, all other conditions were the same as in application example 2. The τ of this liquid crystal composition was measured. off It is 10.9, t -30℃ For >200h

[0125] Comparative Application Example 3

[0126] This comparative application example is identical to application example 3 except that the liquid crystal compound P-3 is not added and the 3CDPUF content percentage is 6%. The τ of this liquid crystal composition was measured. off It is 12.8, t -30℃ For >200h

[0127] Comparative Application Example 4

[0128] In this comparative application example, except that liquid crystal compound P-4 was not added, the content percentage of 3CDPUF was 5.5%, and the content percentage of 2DCPUF was 3.5%, all other conditions were the same as in application example 4. The τ of this liquid crystal composition was measured. off It is 6.8, t -30℃ For >200h

[0129] In the application example, the specific meaning of the codes in each liquid crystal molecule is shown in Table 5.

[0130] Table 5

[0131]

[0132]

[0133] Take the following compound with the following structural formula as an example:

[0134] If the structural formula is represented by the codes listed in Table 1, it can be expressed as: nCCGF, where n in the code represents the number of C atoms in the alkyl group at the left end. For example, if n is "3", it means that the alkyl group is -C3H7. In the code, C represents cyclohexyl, G represents 2-fluoro-1,4-phenylene, and F represents fluorine.

[0135] The abbreviated codes for the test items and the test methods in the application examples are as follows:

[0136] Cp is the clearing point (the transition temperature from nematic to isotropic phase, in °C).

[0137] Δn Optical anisotropy (589 nm, 25 °C);

[0138] Δε dielectric anisotropy (1 kHz, 25 °C);

[0139] τ off The time (ms, 25°C) required for the transmittance to decrease from 90% to 10% during power removal;

[0140] t -30℃ Low-temperature storage time (hours, -30℃)

[0141] Cp: ​​Quantitatively determined using DSC;

[0142] Δn: Measured using an Abbe tester at a temperature of 25℃ and a wavelength of 589nm;

[0143] Δε: Δε=ε ∥ -ε ⊥ , where ε ∥ ε is the dielectric constant parallel to the molecular axis. ⊥The dielectric constant is perpendicular to the molecular axis, and the measurement temperature was 25±0.5℃;

[0144] τ off The testing equipment was a DMS-505, and the testing conditions were a square wave, a voltage of 5V, and a frequency of 60Hz; the test box was a 4μm VA box.

[0145] t -30℃ The liquid crystal composition medium was placed in a glass bottle and stored at -30°C, and the time when crystal precipitation was observed was recorded.

[0146] The applicant declares that the detailed process equipment and process flow of this invention are illustrated through the above embodiments, but this invention is not limited to the above detailed process equipment and process flow, that is, it does not mean that this invention must rely on the above detailed process equipment and process flow to be implemented. Those skilled in the art should understand that any improvements to this invention, equivalent substitutions of raw materials for the products of this invention, additions of auxiliary components, and selection of specific methods, all fall within the protection scope and disclosure scope of this invention.

Claims

1. A liquid crystal compound, characterized in that, The structure of the liquid crystal compound is shown in the following formula: Where M is any one of -R, -G1-R or -G1-G2-R, G1 and G2 are independently any one of substituted or unsubstituted cyclopentyl, cyclohexyl or phenyl, R is a hydrocarbon group or hydrocarbon oxygen group, Y is any substituent that satisfies its chemical environment, and n is an integer from 0 to 5.

2. The liquid crystal compound according to claim 1, characterized in that, The R is a C1-12 alkyl, C1-12 alkoxy, C2-12 alkenyl, or C2-12 alkenoxy.

3. The liquid crystal compound according to claim 1, characterized in that, The Y is -F, -OCF3, -CF3, an unsubstituted alkenyl group of C2 to 6, an unsubstituted alkenyl group of C2 to 6, an alkenyl group of C2 to 6 containing at least one -F substituent, or an alkenyl group of C2 to 6 containing at least one -F substituent.

4. The liquid crystal compound according to claim 1, characterized in that, The liquid crystal compound includes Any one of them.

5. A method for synthesizing the liquid crystal compound according to any one of claims 1-4, characterized in that, The synthesis method is shown in the following formula: Where X is any one of Cl, Br or I.

6. The synthesis method according to claim 5, characterized in that, The synthesis includes the following steps: Under a protective atmosphere, compound A, compound B and a first organic solvent are mixed, and a first catalyst is added to react and obtain compound C; Compound C, compound D, a second catalyst, a base, water, and a second organic solvent were mixed and reacted under a protective atmosphere to obtain compound P.

7. The synthesis method according to claim 6, characterized in that, The first organic solvent includes any one or a combination of at least two of toluene, dichlorohexane, petroleum ether, n-heptane, or n-hexane; And / or, the first catalyst comprises any one or a combination of at least two of toluenesulfonic acid, p-toluenesulfonic acid pyridinium salt, or a solid acid catalyst.

8. The synthesis method according to claim 6, characterized in that, The reaction temperature for synthesizing compound C is 40–110 °C, and the reaction time is 1–10 h.

9. The synthesis method according to claim 6, characterized in that, The second organic solvent includes any one or a combination of at least two of toluene, ethanol, tetrahydrofuran, 2-methyltetrahydrofuran, 1,4-dioxane or methyl tert-butyl ether; And / or, the base includes any one or a combination of at least two of sodium carbonate, potassium carbonate, cesium carbonate, sodium hydroxide, potassium hydroxide, lithium hydroxide, potassium tert-butoxide, or sodium tert-butoxide; And / or, the second catalyst comprises any one or a combination of at least two of the following: bis(dibenzylacetone)palladium, tetra(triphenylphosphine)palladium dichloride, bis(triphenylphosphine)palladium dichloride, dichloroditert-butyl-(4-dimethylaminophenyl)phosphine palladium, or 1,1'-bis(diphenylphosphine)ferrocene palladium dichloride.

10. The synthesis method according to claim 6, characterized in that, The reaction for synthesizing compound P was carried out at a temperature of 60–110 °C for 1–10 h.

Images