Liquid crystal molecular compound as well as preparation method and application thereof

Abstract

The invention discloses a liquid crystal molecular compound as well as a preparation method and application thereof. The novel naphthalimide-azobenzene compound synthesized by the preparation method disclosed by the invention is a liquid crystal molecule, has a relatively wide temperature range, and presents an obvious focal cone texture during heating and cooling, namely, the target compound is a hexagonal columnar phase (Cohex). The liquid crystal compound possibly has potential application value in the aspects of material chemistry, biotechnology, medicinal chemistry and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of new materials, and in particular to a liquid crystal molecule compound and a preparation method and application thereof. Background Art

[0002] Liquid crystals (LCs) are a type of soft matter with properties such as anisotropy, short-range order, fluidity, and continuity. They combine some of the properties of crystals and liquids to form the characteristics of liquid crystals. They often form thermotropic liquid crystals or lyotropic liquid crystals in some anisotropic molecules by changing temperature or adding solvents.

[0003] According to the liquid crystal components and their composition conditions, they can be divided into lyotropic liquid crystal and thermotropic liquid crystal. Thermotropic liquid crystal compounds are pure substances whose liquid crystal properties change with temperature; however, lyotropic liquid crystal is a mixture, and its properties are mainly related to solvents and concentrations. According to the different liquid crystal phases exhibited by thermotropic liquid crystals, they can be divided into cholesteric liquid crystal, nematic liquid crystal, smectic liquid crystal, columnar phase and other categories. Nematic liquid crystal is a liquid crystal phase that is orderly arranged in one dimension. At the same time, compared with cholesteric liquid crystal and smectic liquid crystal, nematic liquid crystal has the best fluidity. Cholesteric liquid crystal is a special form of nematic liquid crystal. Most of them are derivatives of cholesterol and are spiral-shaped, so they have high optical activity. Smectic liquid crystal is a liquid crystal that is orderly arranged in two dimensions and is most similar to a solid structure, while still having anisotropy. On the basis of the columnar phase, it can still be subdivided into three categories: tilted columnar phase, tetragonal columnar phase, and hexagonal columnar phase. According to the different geometric shapes of the molecules, it can be divided into three types: rod-shaped, banana-shaped and disc-shaped liquid crystals.

[0004] Ubiquitous liquid crystal materials have been widely used in liquid crystal displays, digital cameras, projectors and other devices. Designing novel liquid crystal molecules, discovering new liquid crystal phase types, and deepening the understanding of the self-assembly of soft matter to form liquid crystal functional materials by exploring the relationship between the structure and properties of liquid crystal molecules are currently hot topics in the field of liquid crystal research. Regulating molecular self-assembly through external response is an important part of liquid crystal chemistry. Azobenzene and naphthalene diimide are two important structures in liquid crystal chemistry. It is very necessary to rationally design new naphthalene diimide-azobenzene liquid crystal molecules by combining the photoresponsiveness of azobenzene and the redox property of naphthalene diimide. Summary of the invention

[0005] In view of the above technical problems, the first object of the present invention is to provide a liquid crystal molecule compound, the second object is to provide a method for preparing the compound, and the third object is to provide an application thereof. The compound has a hexagonal columnar phase (Col hex )Focal conic texture is a typical liquid crystal molecular compound.

[0006] In order to achieve the first objective, the present invention provides a liquid crystal molecule compound, characterized in that the structure

[0007] The formula is:

[0008]

[0009] The compound has a planar rigid central group and surrounding flexible side chains, a hexagonal columnar phase, and is a discotic liquid crystal compound.

[0010] The second object of the present invention is achieved as follows: a method for preparing the liquid crystal molecular compound, characterized in that: methyl gallate is used as a starting reactant to obtain intermediate 3 through three steps of etherification, reduction, and chlorination; p-nitrophenol is used as a starting reactant to obtain intermediate 4 through one step of azotization, and then intermediate 3 and intermediate 4 are used to obtain intermediate 6 through two different steps of etherification; then naphthalene dicarboxylic anhydride is used as a starting reactant to synthesize azide intermediate 8 through two steps; finally, intermediate 6 and intermediate 8 are subjected to a click reaction to synthesize target compound molecule 9; the reaction formula is:

[0011] In the above scheme, intermediate 1 is synthesized according to the following method: methyl gallate and potassium carbonate are added to a reaction vessel in sequence, and then a solvent DMF is added, and the mixture is refluxed; then n-decane bromide is slowly added, and the reaction is continued until the reaction is complete. After the reaction solution is cooled to room temperature, the organic layer is extracted with ethyl acetate, and the organic layer is washed with saturated brine and dried with anhydrous sodium sulfate. The solvent is evaporated to obtain a crude product, and the crude product is separated and purified by column chromatography to finally obtain a white solid intermediate.

[0012] In the above scheme, intermediate 2 is synthesized according to the following method: intermediate 1 is added to a reaction container, THF is added, aluminum tetrahydride is added under ice bath conditions, and then the reaction is carried out at room temperature until the reaction is complete. After the reaction is complete, water is slowly added dropwise to the reaction solution under ice bath conditions, and a large amount of bubbles and white solids are observed to be generated. Dilute hydrochloric acid is added until no more bubbles are generated; extraction is carried out with ethyl acetate, all organic layers are dried over anhydrous sodium sulfate, and the organic solvent is completely evaporated to obtain a crude product, which is separated and purified by column chromatography to obtain intermediate 2.

[0013] In the above scheme, intermediate 3 is synthesized according to the following method: intermediate 2, tetrahydrofuran and N,N-dimethylformamide are added to a reaction vessel, stirred, thionyl chloride is added dropwise and reacted at room temperature, and after the reaction is completed, thionyl chloride, tetrahydrofuran and N,N-dimethylformamide in the solution are distilled off under reduced pressure to obtain white solid intermediate 3.

[0014] In the above scheme, the synthesis method of intermediate 4 is: add KOH to the reaction container, then add water, stir under ice bath conditions until cooled to room temperature, then add p-nitrophenol, start the reaction at 120°C, and after the temperature reaches 120°C, gradually increase the temperature to 200°C at 5°C / time. After the reaction is completed, cool to room temperature, add water, adjust the pH value to 3-4 with dilute hydrochloric acid, extract with ethyl acetate, dry with anhydrous sodium sulfate, and evaporate to dryness under reduced pressure to obtain a dark yellow crude product, separate and purify by column chromatography, and finally evaporate to dryness to obtain an orange-yellow solid intermediate 4.

[0015] In the above scheme, the synthesis method of intermediate 5 is: add intermediate 4 and intermediate 3 and potassium carbonate into a reaction container and completely dissolve them in N,N-dimethylformamide. After the reflux reaction is complete, the reaction solution is cooled to room temperature, and then water is added to the solution, extracted with ethyl acetate and washed with saturated brine, then dried with anhydrous sodium sulfate, the desiccant is filtered out, and the crude product is evaporated under reduced pressure to obtain a crude product, which is separated and purified by column chromatography to finally obtain a yellow solid intermediate 5.

[0016] In the above scheme, the synthesis method of intermediate 6 is: add intermediate 5 and potassium carbonate into a reaction container, add solvent acetonitrile, react at 80-85°C, then add propargyl bromide, reflux reaction after completion, extract with ethyl acetate, after extraction is completed, wash the organic layer with sodium hydroxide aqueous solution and saturated brine respectively, dry with anhydrous sodium sulfate, filter out the desiccant, evaporate to dryness under reduced pressure, separate and purify the crude product by column chromatography, and finally obtain intermediate 6.

[0017] In the above scheme, the synthesis method of intermediate 7 is: naphthalene dicarboxylic anhydride, ethylamine bromide and acetic acid are added to a reaction container, and after the reflux reaction is complete, a solid compound is obtained by suction filtration, and then the solid is washed with methanol and dried to obtain intermediate 7.

[0018] In the above scheme, the synthesis method of intermediate 8 is: add intermediate 7, sodium azide and DMF into a reaction vessel, cool to room temperature after the reflux reaction is complete, add water, filter under reduced pressure to obtain a solid, then dissolve the solid in chloroform, dry with anhydrous sodium sulfate, filter out the desiccant, evaporate the chloroform under reduced pressure, and separate and purify the obtained crude product by column chromatography to obtain intermediate 8.

[0019] In the above scheme, the synthesis method of the target product 9 is: add intermediate 6, intermediate 8, and N,N-dimethylformamide into a reaction container, reflux reaction under nitrogen protection until the reaction is complete, cool the reaction solution to room temperature, add water, extract with chloroform, then wash with saturated brine and dry with anhydrous sodium sulfate, filter to remove the desiccant, evaporate chloroform under reduced pressure to obtain a crude product, separate and purify by column chromatography, evaporate the mixed solvent under reduced pressure to obtain a crude product, and finally recrystallize with a mixed solvent of methanol, acetone and dichloromethane to obtain the product.

[0020] The volume ratio of methanol:acetone:dichloromethane is 1:1:1.

[0021] The liquid crystal molecular compound is used as a liquid crystal material to make liquid crystal devices, such as liquid crystal displays, digital cameras, and projectors.

[0022] Beneficial effects: The present invention uses methyl gallate and p-nitrophenol as starting materials to design and synthesize alkynyl compounds, then synthesizes naphthalene diimide derivatives from naphthalene dicarboxylic anhydride, and finally designs and synthesizes a new type of naphthalene diimide-azobenzene liquid crystal molecule compound using click reaction as the key step. 1 HNMR and 13 C NMR was used to characterize the structure. In addition, the texture of the target molecular compound at the corresponding temperature was observed under heating conditions by polarizing microscopy (POM), and the liquid crystal phase of the target molecular compound was analyzed. The research results show that the synthesized new naphthalene diimide-azobenzene compound is a liquid crystal molecule with a wide temperature range. It exhibits obvious focal conic texture when heating and cooling, that is, the target compound is a hexagonal columnar phase (Col hex ). This type of liquid crystal compound may have potential application value in material chemistry, biotechnology and medicinal chemistry. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is the hydrogen nuclear magnetic resonance spectrum of the target product of the present invention.

[0024] Figure 2 It is the carbon nuclear magnetic resonance spectrum of the target product of the present invention.

[0025] Figure 3 The hexagonal columnar phase (Col hex ) focal conic texture, where

[0026] a: Texture observed at 170°C b: Texture observed at 170°C (with filter added) c: Texture observed at 200°C d: Texture observed at 200°C (with filter added).

[0027] Figure 4 The hexagonal columnar phase (Col hex ) schematic diagram of the self-assembly process. DETAILED DESCRIPTION

[0028] The present invention will be further described below by way of examples:

[0029] Example 1

[0030] Synthesis of intermediate 1:

[0031]

[0032] Methyl gallate (2 g, 10.9 mmol), potassium carbonate (9 g, 65.2 mmol), and DMF (30 mL) were added to a round-bottom flask in sequence, and the mixture was refluxed at 95 °C for 0.5 h. 10 H 21 Br (9.2mL, 43.4mmol) was slowly added to the solution in the round-bottom flask, and the reaction was continued for 12h. When the solution turned black, thin layer chromatography (TLC) was used to determine that the reaction was complete. The reaction solution was cooled to room temperature and placed in a separatory funnel to extract the organic layer with ethyl acetate solvent, which was washed with saturated brine 5 times and dried with anhydrous sodium sulfate for 0.5h. The solvent was evaporated to obtain a crude product, which was separated and purified by column chromatography (petroleum ether: ethyl acetate = 60:1). Finally, 5.52g of white solid was obtained, and the calculated yield was 84%.

[0033] Example 2

[0034] Synthesis of intermediate 2:

[0035]

[0036] Add intermediate 1 (2.9 g, 4.8 mmol) to the flask, then add THF (10 mL) as solvent, quickly add aluminum tetrahydride (0.28 g, 7.4 mmol) under ice bath conditions, and react at room temperature for 12 h. After the reaction is complete, slowly add water to the reaction solution under ice bath conditions, and observe that a large number of bubbles and white solids are generated, then add dilute hydrochloric acid (2 M) until no more bubbles are generated; extract with ethyl acetate three times, 30 mL each time, dry all the organic layers with anhydrous sodium sulfate, and then use a rotary evaporator to completely evaporate the organic solvent to obtain a crude product, and separate and purify the crude product by column chromatography (petroleum ether: ethyl acetate = 5:1). Finally, 2.65 g of white solid is obtained, and the calculated yield is 96%.

[0037] Example 3

[0038] Synthesis of intermediate 3:

[0039]

[0040] Add intermediate 2 (2.65 g, 4.6 mmol), tetrahydrofuran (10 mL) and N,N-dimethylformamide (2-3 drops) into a round-bottom flask and stir. Then drop thionyl chloride (0.4 mL, 5.5 mmol) and react at room temperature for 5 h. After the reaction is completed, remove thionyl chloride, tetrahydrofuran and N,N-dimethylformamide from the solution by vacuum distillation at about 70 ° C to obtain 2.6 g of white solid, with a calculated yield of 95%.

[0041] Example 4

[0042] Synthesis of intermediate 4:

[0043]

[0044] Add KOH (30g, 534mmol) to a round-bottom flask, then add water (6mL), stir under ice bath conditions until cooled to room temperature, then add p-nitrophenol (4.7g, 33.8mmol), start the reaction at 120°C, and after the temperature reaches 120°C, gradually increase the temperature to 200°C at 5°C / times for 4h. Use thin layer chromatography (TLC) to detect whether the reaction is complete. After confirming that the reaction is complete, cool to room temperature, add an appropriate amount of water to the round-bottom flask, and then pour it into a beaker. Use dilute HCl (2M) to adjust the pH value of the solution to 3-4, extract with ethyl acetate three times, 30mL each time, then put the organic matter extracted several times together, dry with anhydrous sodium sulfate, and then evaporate to dryness under reduced pressure to obtain a dark yellow crude product, separate and purify by column chromatography (petroleum ether: ethyl acetate = 2:1), and finally evaporate to dryness to obtain 1.9g of orange-yellow solid, with a calculated yield of 28%.

[0045] Example 5

[0046] Synthesis of intermediate 5:

[0047]

[0048] Add intermediate 4 (0.48 g, 2.2 mmol) and intermediate 3 (1.33 g, 2.2 mmol) and potassium carbonate (0.93 g, 6.7 mmol) to a round-bottom flask and completely dissolve them in N,N-dimethylformamide (20 mL) and reflux at 90°C for 10 h. After the reaction is complete, cool the reaction solution in the flask to room temperature, then add an appropriate amount of water to the solution, extract with ethyl acetate and wash with saturated brine 5 times, then dry with anhydrous sodium sulfate for 0.5 h, filter out the desiccant, evaporate to dryness under reduced pressure to obtain a crude product, separate and purify it by column chromatography (petroleum ether: ethyl acetate = 10:1). Finally, 0.44 g of yellow solid was obtained, and the calculated yield was 26%.

[0049] Example 6

[0050] Synthesis of intermediate 6:

[0051]

[0052] Add intermediate 5 (0.42g, 0.54mmol), potassium carbonate (0.11g, 0.79mmol) and solvent acetonitrile (10mL) to a round-bottom flask and react at 80°C for 30min. Add propargyl bromide (0.13g, 1mmol) with a syringe and reflux at 80°C for 12h. After the reaction is complete, extract with ethyl acetate three times. After the extraction is completed, wash the organic layer with sodium hydroxide aqueous solution and saturated brine, dry with anhydrous sodium sulfate, and filter out the desiccant. Evaporate the crude product under reduced pressure and separate and purify it by column chromatography (petroleum ether: ethyl acetate = 10:6). Finally, 0.23g of yellow product is obtained, and the calculated yield is 53%.

[0053] Example 7

[0054] Synthesis of intermediate 7:

[0055]

[0056] Naphthalene dicarboxylic anhydride (0.143 g, 0.50 mmol) was added to a round-bottom flask, followed by ethyl bromide (0.16 g, 1.3 mmol), and finally acetic acid (10 mL) as a solvent, and the mixture was refluxed at 90°C for 12 h. After the reaction was complete as detected by thin layer chromatography (TLC), a solid compound was directly filtered, and then the solid was washed with methanol and dried to obtain 241 mg of the product, with a calculated yield of 95%.

[0057] Example 8

[0058] Synthesis of intermediate 8:

[0059]

[0060] Add intermediate 7 (0.20 g, 0.42 mmol) to a round-bottom flask, then add sodium azide (0.27 g, 4.2 mmol), and finally add DMF (10 mL) as solvent, and reflux at 50 ° C for 12 h. After the reaction is complete by thin layer chromatography (TLC), the reaction solution in the flask is cooled to room temperature and then an appropriate amount of water is added to directly reduce pressure and filter to obtain a solid, and then the solid is dissolved in chloroform, dried with anhydrous sodium sulfate, the desiccant is filtered out, and the chloroform is evaporated under reduced pressure. The crude product is separated and purified by column chromatography (chloroform: ethyl acetate = 50: 1). Finally, 120 mg of a yellow product is obtained, and the calculated yield is 71%.

[0061] Example 9

[0062] Synthesis of target product 9:

[0063]

[0064] Add intermediate 6 (0.36 g, 0.44 mmol) to a round-bottom flask, then add intermediate 8 (0.078 g, 0.19 mmol), and finally add N, N-dimethylformamide (10 mL) as solvent, reflux for 20 h at 75 ° C under nitrogen protection reaction conditions. After the reaction is complete by thin layer chromatography (TLC), the reaction solution in the flask is cooled to room temperature, and then an appropriate amount of water is added, extracted twice with chloroform, the organic phases are combined, and then washed with saturated brine 5 times and dried with anhydrous sodium sulfate for 0.5 h, the desiccant anhydrous sodium sulfate is filtered out, and chloroform is evaporated under reduced pressure to obtain a crude product, which is separated and purified by column chromatography (chloroform: methanol = 130: 1), and the mixed solvent is evaporated under reduced pressure to obtain a crude product, and finally recrystallized with a mixed solvent of methanol (5 mL), acetone (5 mL), and dichloromethane (5 mL), directly filtered, and dried to obtain 82 mg of a red-black solid with a yield of 21%.

[0065] Example 10

[0066] Target compound structure confirmation

[0067] The H NMR spectra of the target compounds were determined. Figure 1 ) and C NMR spectra (such as Figure 2 ), and then compare the measured data with the data simulated by Chemdraw software to determine that the target compound obtained is the target compound designed and synthesized by us.

[0068] Data obtained from the hydrogen nuclear magnetic resonance spectrum: 1 H NMR (500 MHz, CDCl 3 ): δ=8.75-8.41(m,4H),7.86(d,J=8.8Hz,4H),7.84-7.73(m,6H),7.07(d,J=8 .9Hz,4H),7.03(d,J=8.8Hz,4H),6.64(s,4H),5.20(d,J=32.5Hz,4H),5.02(s, 4H),4.77(t,J=5.6Hz,4H),4.62(t,J=5.7Hz,4H),4.02-3.93(m,13H),1.86-1. 69(m,14H),1.46(dd,J=13.9,6.5Hz,13H),1.25(s,133H),0.95–0.78(m,19H).

[0069] Data obtained from carbon nuclear magnetic resonance spectroscopy: 13C NMR (CDCl 3 ,125MHz): δ=162.64,167.67,161.02,160.77,160.23,154.40,153.53,148.24,147.39,147.3 3,147.25,138.20,131.52,131.40,129.60,126.89,126.60,126.29,124.93,124.59,124.49, 124.04,115.22,115.18,106.31,74.41,71.62,70.82,69.60,69.31,62.24,61.30,47.90,40.13,32.10,29.94,29.93,29.89,29.84,29.83,29.61,29.59,29.56,29.55,26.29,22.87,14.30

[0070] The data obtained by nuclear magnetic resonance measurement prove that the structure of the target product is consistent with that represented by the structural formula.

[0071] The target molecular compound was measured by polarizing microscope (POM) and its liquid crystal phase texture at the corresponding temperature was observed. The measurement proved that the prepared naphthalene diimide-azobenzene liquid crystal (target product) is a liquid crystal, and the liquid crystal phase change has a wide temperature range, that is, the temperature rise range is 220℃ and the temperature drop range is 205℃. Under polarizing microscope, the compound exhibits a hexagonal columnar phase (Col hex ), and then heated to 50°C, the naphthalene diimide-azobenzene liquid crystal molecule compound showed a typical hexagonal columnar phase (Col hex )(like Figure 3 ), and when the target compound is further heated to 220°C, no hexagonal columnar phase can be seen (Col hex ); During the cooling process, a hexagonal columnar phase will appear in the range of 205℃-RT (Col hex ). The target product of the present invention has reversible photophysical properties and is expected to be used in photoelectric molecular switches.

[0072] The present invention is not limited to the above-mentioned embodiments. Those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and purpose of the present invention. The scope of the present invention is defined by the claims and their equivalents.

Claims

1. A liquid crystal molecule compound, characterized in that: The structural formula is:

2. A method for preparing the liquid crystal molecule compound according to claim 1, characterized in that: Using methyl gallate as the starting reactant, the intermediate 3 is obtained through etherification, reduction and chlorination in three steps; using p-nitrophenol as the starting reactant, the intermediate 4 is obtained through azotization in one step, and then the intermediate 3 and the intermediate 4 are subjected to two different etherification steps to obtain the intermediate 6; then using naphthalene dicarboxylic anhydride as the starting reactant, the azide intermediate 8 is synthesized in two steps; finally, the intermediate 6 and the intermediate 8 are subjected to a click reaction to synthesize the target compound molecule 9; the reaction formula is:

3. The method for preparing a liquid crystal molecule compound according to claim 2, characterized in that: Intermediate 1 was synthesized as follows: methyl gallate and potassium carbonate were added to a reaction vessel in sequence, and then a solvent DMF was added, and the mixture was refluxed; then n-decane bromide was slowly added, and the reaction was continued until the reaction was complete. The reaction solution was cooled to room temperature, and then extracted with ethyl acetate to obtain an organic layer, which was washed with saturated brine and dried over anhydrous sodium sulfate. The solvent was evaporated to obtain a crude product, and the crude product was separated and purified by column chromatography to finally obtain a white solid intermediate.

4. The method for preparing a liquid crystal molecule compound according to claim 2 or 3, characterized in that: Intermediate 2 was synthesized according to the following method: intermediate 1 was added to a reaction container, THF was added, aluminum tetrahydride was added under ice bath conditions, and the reaction was continued at room temperature until the reaction was complete. After the reaction was complete, water was slowly added dropwise to the reaction solution under ice bath conditions, and a large amount of bubbles and white solids were observed to be generated. Dilute hydrochloric acid was added until no more bubbles were generated. The mixture was extracted with ethyl acetate, all organic layers were dried over anhydrous sodium sulfate, and the organic solvent was completely evaporated to obtain a crude product, which was separated and purified by column chromatography to obtain intermediate 2.

5. The method for preparing a liquid crystal molecule compound according to claim 4, characterized in that: Intermediate 3 is synthesized as follows: intermediate 2, tetrahydrofuran and N,N-dimethylformamide are added to a reaction vessel, stirred, thionyl chloride is added dropwise and reacted at room temperature. After the reaction is completed, thionyl chloride, tetrahydrofuran and N,N-dimethylformamide in the solution are distilled off under reduced pressure to obtain white solid intermediate 3.

6. The method for preparing a liquid crystal molecule compound according to claim 5, characterized in that: The synthesis method of intermediate 4 is as follows: KOH is added to a reaction container, and then water is added, and the mixture is stirred under ice bath conditions until it is cooled to room temperature, and then p-nitrophenol is added, and the reaction is started at 120°C. After the temperature reaches 120°C, the temperature is gradually increased to 200°C at a rate of 5°C / time. After the reaction is completed, the mixture is cooled to room temperature, water is added, the pH value is adjusted to 3-4 with dilute hydrochloric acid, extracted with ethyl acetate, dried with anhydrous sodium sulfate, and evaporated to dryness under reduced pressure to obtain a dark yellow crude product, which is separated and purified by column chromatography, and finally evaporated to dryness to obtain an orange-yellow solid intermediate 4.

7. The method for preparing a liquid crystal molecule compound according to claim 6, characterized in that: The synthesis method of intermediate 5 is as follows: intermediate 4 and intermediate 3, potassium carbonate are added to a reaction container and are completely dissolved in N,N-dimethylformamide. After the reflux reaction is complete, the reaction solution is cooled to room temperature, and then water is added to the solution, extracted with ethyl acetate and washed with saturated brine, and then dried with anhydrous sodium sulfate, the desiccant is filtered out, and the crude product is evaporated under reduced pressure to obtain a crude product, which is separated and purified by column chromatography to finally obtain a yellow solid intermediate 5.

8. The method for preparing a liquid crystal molecule compound according to claim 7, characterized in that: The synthesis method of intermediate 6 is as follows: intermediate 5 and potassium carbonate are added to a reaction container, and acetonitrile is added as a solvent, and the mixture is reacted at 80-85° C., propargyl bromide is added, and after the reflux reaction is completed, the mixture is extracted with ethyl acetate. After the extraction is completed, the organic layer is washed with an aqueous sodium hydroxide solution and a saturated saline solution, respectively, and dried with anhydrous sodium sulfate, the desiccant is filtered out, and the crude product obtained by evaporation under reduced pressure is separated and purified by column chromatography to finally obtain intermediate 6.

9. The method for preparing a liquid crystal molecule compound according to claim 8, characterized in that: The synthesis method of intermediate 7 is as follows: naphthalene dicarboxylic anhydride, ethylamine bromide and acetic acid are added to a reaction container, and after the reflux reaction is complete, a solid compound is obtained by suction filtration, and then the solid is washed with methanol and dried to obtain intermediate 7.

10. The method for preparing a liquid crystal molecule compound according to claim 9, characterized in that: The synthesis method of intermediate 8 is as follows: intermediate 7, sodium azide and DMF are added to a reaction vessel, and after the reflux reaction is complete, the reaction is cooled to room temperature, and water is added, and a solid is obtained by filtration under reduced pressure. The solid is then dissolved in chloroform, and the solid is dried over anhydrous sodium sulfate, the desiccant is filtered out, and the chloroform is evaporated under reduced pressure. The obtained crude product is separated and purified by column chromatography to obtain intermediate 8.

11. The method for preparing a liquid crystal molecule compound according to claim 9, characterized in that: The synthesis method of the target product 9 is as follows: add intermediate 6, intermediate 8, and N,N-dimethylformamide into a reaction container, reflux under nitrogen protection until the reaction is complete, cool the reaction solution to room temperature, add water, extract with chloroform, wash with saturated brine and dry with anhydrous sodium sulfate, filter to remove the desiccant, evaporate chloroform under reduced pressure to obtain a crude product, separate and purify by column chromatography, evaporate the mixed solvent under reduced pressure to obtain a crude product, and finally recrystallize with a mixed solvent of methanol, acetone and dichloromethane to obtain the product.

12. Use of the liquid crystal molecular compound according to claim 1 as a liquid crystal material for making a liquid crystal device.

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