A liquid crystal compound, its preparation method and application

Abstract

This invention belongs to the field of liquid crystal material technology, specifically relating to a liquid crystal compound, its preparation method, and its application. The liquid crystal compound of this invention exhibits a large negative dielectric anisotropy, high-definition brightness, relatively high optical anisotropy, moderate rotational viscosity and liquid crystal miscibility, excellent low-temperature performance, and good thermal stability, chemical stability, optical stability, and mechanical properties. This effectively reduces the driving voltage, improves the response speed of the liquid crystal display device, and also features moderate optical anisotropy and high charge retention.

Description

Technical Field

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

[0002] In recent years, LCD display devices have developed rapidly, resulting in various types such as small automotive LCD displays, portable LCD displays, and ultra-thin LCD displays. Taking televisions as an example, LCD display devices are characterized by their light weight, small footprint, and portability, as seen in devices like laptops and mobile phones.

[0003] Liquid crystal materials, as environmentally friendly materials, have significant research value and promising application prospects in fields such as information display materials and organic optoelectronic materials. Currently, TFT-LCD technology is mature, successfully solving technical challenges such as viewing angle, resolution, color saturation, and brightness. Large-size and small-to-medium-size TFT-LCD displays have gradually become the mainstream flat panel displays in their respective fields. However, the demands on display technology continue to rise, such as requiring liquid crystal displays to achieve faster response times, lower power consumption, wider temperature ranges, and better low-temperature stability.

[0004] Liquid crystal materials themselves play an important role in improving the performance of liquid crystal displays. Therefore, in order to improve the performance of liquid crystal displays, the synthesis of novel liquid crystal compounds and the study of structure-property relationships have become an important task in the field of liquid crystals.

[0005] Therefore, this invention is proposed. Summary of the Invention

[0006] This invention provides liquid crystal compounds, their preparation methods, and applications, which improve the performance of liquid crystal display devices by designing liquid crystal compounds with novel structures.

[0007] Specifically, the present invention provides a liquid crystal compound having the structural formula as described in general formula (I):

[0008]

[0009] In general formula I, R1 represents an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an alkyl group having 1 to 10 carbon atoms substituted with F, an alkoxy group having 1 to 10 carbon atoms substituted with F, a cyclopropyl group, a cyclobutyl group, or a cyclopentyl group.

[0010] R2 represents an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an alkyl group having 1 to 10 carbon atoms substituted with F, an alkenyl group having 1 to 10 carbon atoms substituted with F, an alkenyl group having 2 to 10 carbon atoms substituted with F, or an alkoxy group having 1 to 10 carbon atoms substituted with cyclopropyl, cyclobutyl, or cyclopentyl.

[0011] Z represents -CH2CH2O-, -CH2CH2CH2O-, or -CH2CH2CH2CH2O-;

[0012] According to the present invention, R1 represents an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alkyl group having 1 to 6 carbon atoms substituted with F, an alkoxy group having 1 to 6 carbon atoms substituted with F, a cyclopropyl group, a cyclobutyl group, or a cyclopentyl group.

[0013] R2 represents an alkyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, an alkyl group having 1 to 5 carbon atoms substituted with F, an alkenyl group having 1 to 5 carbon atoms substituted with F, an alkenyl group having 2 to 5 carbon atoms substituted with F, or an alkoxy group having 1 to 5 carbon atoms substituted with cyclopropyl, cyclobutyl, or cyclopentyl.

[0014] Z represents -CH2CH2O-, -CH2CH2CH2O-, or -CH2CH2CH2CH2O-;

[0015] According to the present invention, a liquid crystal compound has the following structural formula:

[0016]

[0017]

[0018]

[0019]

[0020]

[0021]

[0022]

[0023]

[0024]

[0025]

[0026]

[0027]

[0028] The liquid crystal compound provided by the present invention has the following structural formula:

[0029]

[0030]

[0031] or

[0032]

[0033] The liquid crystal compound provided by the present invention has the following structural formula:

[0034]

[0035] The present invention also provides a method for preparing the liquid crystal compound as described above, the synthetic route of which is as follows:

[0036]

[0037] The preparation method provided by the present invention includes the following steps:

[0038] 1) The metallization reaction with an organolithium reagent, followed by a reaction with a borate ester, yields...

[0039] 2) and Through the suzuki reaction, we obtain

[0040] 3) It undergoes a substitution reaction with (CF3SO2)2O to give

[0041] 4) Reaction with ethyl mercaptopropionate yields

[0042] 5) The ring-closure was carried out under alkaline catalysis to obtain...

[0043] Among them, R1, Z and R2 refer to the same things as in the previous part.

[0044] Preferably, in step 1) of the above method, The molar ratio of the organic lithium reagent to the borate ester is 1:1.0 to 2.0, and the molar ratio of the borate ester to the organic lithium reagent is 1:1.0 to 3.0.

[0045] Preferably, the reaction temperature can be between -50 and -100°C;

[0046] in, It can be obtained through open commercial channels; the organolithium reagent is selected from one or more of sec-butyllithium, tert-butyllithium, and n-butyllithium; the borate ester is selected from one or more of trimethyl borate, triisopropyl borate, tributyl borate, and triisobutyl borate.

[0047] In step 2) of the above method, and The molar ratio of the feed materials is 1.0:1.0~1.5;

[0048] Preferably, the reaction temperature can be between 60 and 140°C;

[0049] Among them, raw materials It can be obtained through open commercial channels.

[0050] In step 3) of the above method, The molar ratio of (CF3SO2)2O to the feed is 1.0–2.0:2;

[0051] Preferably, the reaction temperature can be between 0 and 20°C;

[0052] In step 4), The molar ratio of the feed to ethyl mercaptopropionate is 1:1.0 to 2.0;

[0053] Preferably, the reaction temperature is 50–150°C.

[0054] In step 5), The molar ratio of feed to alkali is 1:1.0 to 4.0;

[0055] Preferably, the reaction temperature is 80–150°C, and the alkali can be potassium tert-butoxide and / or sodium tert-butoxide, etc.

[0056] The above preparation method can obtain the liquid crystal compound of the present invention more stably and efficiently.

[0057] In this invention, those skilled in the art can use conventional post-processing methods according to actual needs when using the above preparation method. Preferably, the conventional post-processing includes: extraction with dichloromethane, ethyl acetate or toluene, separation, washing with water, drying, evaporation in a vacuum rotary evaporator, and purification of the obtained product by vacuum distillation or recrystallization and / or chromatographic separation.

[0058] The present invention also provides a liquid crystal composition comprising the above-mentioned liquid crystal compound.

[0059] Preferably, the liquid crystal compound comprises 0.01 to 60% by mass in the liquid crystal composition;

[0060] More preferably, it is 0.1% to 50%; even more preferably, it is 0.1% to 40%.

[0061] The present invention further provides the application of the above-described liquid crystal compound or liquid crystal composition in the field of liquid crystal display, preferably in the application of liquid crystal display device.

[0062] More preferably, the liquid crystal display device includes a VA, TN, STN, FFS, or IPS liquid crystal display.

[0063] This invention provides a liquid crystal compound, its preparation method, and its application. By optimizing the structure, the liquid crystal compound exhibits large dielectric anisotropy, high-definition bright spots, relatively high optical anisotropy, moderate rotational viscosity and liquid crystal miscibility, excellent low-temperature performance, and good thermal stability, chemical stability, optical stability, and mechanical properties. This effectively reduces the driving voltage, improves the response speed of the liquid crystal display device, and also features moderate optical anisotropy and high charge retention. Detailed Implementation

[0064] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this invention, not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0065] Where specific techniques or conditions are not specified in the examples, they shall be performed in accordance with the techniques or conditions described in the literature in this field, or in accordance with the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased through legitimate channels.

[0066] Example 1

[0067] A method for preparing a liquid crystal compound, wherein the liquid crystal compound has the following structural formula:

[0068]

[0069] The synthetic route for this liquid crystal compound is as follows:

[0070]

[0071] The specific preparation steps of this liquid crystal compound are as follows:

[0072] (1) Synthesis of compound BYLC-01-1:

[0073] Under nitrogen protection, 73.6 g (0.261 mol) was added to the reaction flask.

[0074] 150 mL of tetrahydrofuran was added dropwise to a 0.45 mol n-butyllithium solution in hexane at a controlled temperature of -70 to -80 °C. After the addition was complete, the reaction was carried out at a controlled temperature for 1 hour. Then, 48.0 g of trimethyl borate (0.45 mol) was added dropwise at a controlled temperature of -60 to -70 °C, and the mixture was allowed to cool naturally to -30 °C. The mixture was then acidified with 400 mL of 2M hydrochloric acid aqueous solution. After routine post-treatment, recrystallization from petroleum ether yielded 76.6 g of a pale yellow solid (compound BYLC-01-1, 0.235 mol), HPLC: 99.5%, yield: 90%.

[0075] (2) Synthesis of compound BYLC-01-2:

[0076] Under nitrogen protection, 76.6 g (0.235 mol) of compound BYLC-01-1 and 61.5 g (0.235 mol) of compound were added to the reaction flask. 200 ml N,N-dimethylformamide, 100 ml deionized water, 72.8 g anhydrous potassium carbonate (0.53 mol), and 0.5 g tetraphenylphosphine palladium were reacted at 70 °C for 3 hours. Post-treatment: chromatographic purification, elution with n-hexane, and recrystallization from ethanol yielded 92.8 g of a white solid (compound BYLC-01-2, 0.2 mol), GC: 99.8%, yield: 85%.

[0077] (3) Synthesis of compound BYLC-01-3:

[0078] 92.8 g of compound BYLC-01-2 (0.2 mol), 0.3 g of succinic acid, 13.4 g of Et3N, and 180 ml of dichloromethane were added to a 500 ml three-necked flask. The mixture was stirred, protected with N2, and the temperature was controlled at 5–10 °C. 85 g of (CF3SO2)2O (0.300 mol) was added dropwise. After the addition was complete, the mixture was stirred naturally overnight. The reaction solution was washed twice with water (200 ml × 2), dried over anhydrous sodium sulfate, passed through a 40 g silica gel column, and evaporated to dryness to obtain 107.3 g of a white solid (compound BYLC-01-3, 0.18 mol), GC: 99.8%, yield: 90%.

[0079] (4) Synthesis of compound BYLC-01-4

[0080] 107.3 g of compound was added to the reaction flask under nitrogen protection.

[0081] BYLC-01-4 (0.18 mol), 28 g ethyl mercaptopropionate, 26 g N,N-diisopropylethylamine, 0.7 g 2-dicyclohexylphosphine-2,4,6-triisopropylbiphenyl, 0.7 g tris(dibenzylacetone)dipalladium, 280 ml dioxane, reacted at 100℃~105℃ for 6 hours. After routine post-treatment, the mixture was purified by chromatography and eluted with n-hexane to give 83.6 g of a pale yellow liquid (compound BYLC-01-4), GC: 95.8%, yield: 80%.

[0082] (5) Synthesis of compound BYLC-01:

[0083] Under nitrogen protection, 83.6 g of compound BYLC-01-4 (0.144 mol), 200 ml of N,N-dimethylformamide, and 32 g of potassium tert-butoxide were added to a reaction flask. The reaction was carried out at 130–140 °C for 4 hours, and the reaction was monitored by TLC until complete. After routine post-treatment, the mixture was purified by chromatography, eluted with n-hexane, and recrystallized from ethanol to give 46 g of a white solid (compound BYLC-01, 0.1 mol), GC: 99.9%, yield 70%.

[0084] The obtained white solid BYLC-01 was analyzed by GC-MS, and the m / z of the product was 460 (M+).

[0085] Example 2

[0086] A method for preparing a liquid crystal compound, wherein the liquid crystal compound has the following structural formula:

[0087]

[0088] The synthetic route of the compound shown in BYLC-02 is similar to that in Example 1, the main difference being: Replace with

[0089] The obtained white solid BYLC-02 was analyzed by GC-MS, and the m / z of the product was 486 (M+).

[0090] Example 3

[0091] A method for preparing a liquid crystal compound, wherein the liquid crystal compound has the following structural formula:

[0092]

[0093] The synthetic route of the compound shown in BYLC-03 is similar to that in Example 1, the main difference being: Replace with

[0094] The obtained white solid BYLC-03 was analyzed by GC-MS, and the m / z of the product was 458 (M+).

[0095] Example 4

[0096] A method for preparing a liquid crystal compound, wherein the liquid crystal compound has the following structural formula:

[0097]

[0098] The synthetic route of the compound shown in BYLC-04 is similar to that in Example 1, the main difference being: Replace with

[0099] The obtained white solid BYLC-04 was analyzed by GC-MS, and the m / z of the product was 486 (M+).

[0100] Example 5

[0101] A method for preparing a liquid crystal compound, wherein the liquid crystal compound has the following structural formula:

[0102]

[0103] The synthetic route of the compound shown in BYLC-05 is similar to that in Example 1, the main difference being: Replace with

[0104] The obtained white solid BYLC-05 was analyzed by GC-MS, and the m / z of the product was 474 (M+).

[0105] Example 6

[0106] A method for preparing a liquid crystal compound, wherein the liquid crystal compound has the following structural formula:

[0107]

[0108] The synthetic route of the compound shown in BYLC-06 is similar to that in Example 1, the main difference being: Replace with

[0109] Will Replace with

[0110] The obtained white solid BYLC-06 was analyzed by GC-MS, and the m / z of the product was 500 (M+).

[0111] Example 7

[0112] A method for preparing a liquid crystal compound, wherein the liquid crystal compound has the following structural formula:

[0113]

[0114] The synthetic route of the compound shown in BYLC-07 is similar to that in Example 1, the main difference being: Replace with

[0115] Will Replace with

[0116] The obtained white solid BYLC-07 was analyzed by GC-MS, and the m / z of the product was 472 (M+).

[0117] Example 8

[0118] A method for preparing a liquid crystal compound, wherein the liquid crystal compound has the following structural formula:

[0119]

[0120] The synthetic route of the compound shown in BYLC-08 is similar to that in Example 1, the main difference being: Replace with

[0121] The obtained white solid BYLC-08 was analyzed by GC-MS, and the m / z of the product was 500 (M+).

[0122] Example 9

[0123] A method for preparing a liquid crystal compound, wherein the liquid crystal compound has the following structural formula:

[0124]

[0125] The synthetic route of the compound shown in BYLC-09 is similar to that in Example 1, the main difference being: Replace with

[0126] The obtained white solid BYLC-09 was analyzed by GC-MS, and the m / z of the product was 488 (M+).

[0127] Example 10

[0128] A method for preparing a liquid crystal compound, wherein the liquid crystal compound has the following structural formula:

[0129]

[0130] The synthetic route of the compound shown in BYLC-10 is similar to that in Example 1, the main difference being: Replace with

[0131] Will Replace with

[0132] The obtained white solid BYLC-12 was analyzed by GC-MS, and the m / z of the product was 514 (M+).

[0133] Example 11

[0134] A method for preparing a liquid crystal compound, wherein the liquid crystal compound has the following structural formula:

[0135]

[0136] The synthetic route of the compound shown in BYLC-11 is similar to that in Example 1, the main difference being: Replace with

[0137] Will Replace with

[0138] The obtained white solid BYLC-13 was analyzed by GC-MS, and the m / z of the product was 486 (M+).

[0139] Example 12

[0140] A method for preparing a liquid crystal compound, wherein the liquid crystal compound has the following structural formula:

[0141]

[0142] The synthetic route of the compound shown in BYLC-12 is similar to that in Example 1, the main difference being: Replace with

[0143] The obtained white solid BYLC-14 was analyzed by GC-MS, and the m / z of the product was 514 (M+).

[0144] Comparative Example

[0145] A method for preparing a compound, the structural formula of which is as follows:

[0146]

[0147] Experimental Example

[0148] The performance parameters of the compounds prepared in the examples and comparative examples were tested according to conventional testing methods in the art. For example, γ1 was measured using a viscometer, Δn was measured using an Abbe refractometer, and Δε was measured using an INSTEC liquid crystal testing instrument. The various performance parameters of the liquid crystal compounds were obtained through linear fitting. The specific meanings of each performance parameter are as follows: Δn represents optical anisotropy (25℃); Δε represents dielectric anisotropy (25℃, 1000Hz); γ1 represents rotational viscosity (mPa·s, 25℃). The test results are shown in the table below.

[0149]

[0150]

[0151] As can be seen from the above experimental data, the liquid crystal compound provided by the present invention has a greater negative dielectric anisotropy and a lower rotational viscosity.

[0152] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A liquid crystal compound, characterized in that, It has a structural formula as described in general formula (I): ； In general formula I, R1 represents an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an alkyl group having 1 to 10 carbon atoms substituted with F, an alkoxy group having 1 to 10 carbon atoms substituted with F, a cyclopropyl group, a cyclobutyl group, or a cyclopentyl group. R2 represents an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an alkyl group having 1 to 10 carbon atoms substituted with F, an alkenyl group having 1 to 10 carbon atoms substituted with F, an alkenyl group having 2 to 10 carbon atoms substituted with F, or an alkoxy group having 1 to 10 carbon atoms substituted with cyclopropyl, cyclobutyl, or cyclopentyl. Z represents -CH2CH2O-, -CH2CH2CH2O-, or -CH2CH2CH2CH2O-.

2. The liquid crystal compound according to claim 1, characterized in that, R1 represents an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alkyl group having 1 to 6 carbon atoms substituted with F, an alkoxy group having 1 to 6 carbon atoms substituted with F, a cyclopropyl group, a cyclobutyl group, or a cyclopentyl group. R2 represents an alkyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, an alkyl group having 1 to 5 carbon atoms substituted with F, an alkoxy group having 1 to 5 carbon atoms substituted with F, an alkenyl group having 2 to 5 carbon atoms substituted with F, or an alkoxy group having 1 to 5 carbon atoms substituted with cyclopropyl, cyclobutyl, or cyclopentyl. Z represents -CH2CH2O-, -CH2CH2CH2O-, or -CH2CH2CH2CH2O-.

3. The liquid crystal compound according to claim 2, characterized in that, Its structural formula is any one of the following: ； ； ； ； ； ； ； ； ； ； ； 。 4. The liquid crystal compound according to claim 3, characterized in that, Its structural formula is: 、 、 、 、 、 、 、 、 、 、 or 。 5. The liquid crystal compound according to claim 4, characterized in that, Its structural formula is: 。 6. A method for preparing the liquid crystal compound according to any one of claims 1 to 5, characterized in that, The synthetic route of the liquid crystal compound is as follows: 。 7. The preparation method according to claim 6, characterized in that, Includes the following steps: 1) The metallization reaction with an organolithium reagent, followed by a reaction with a borate ester, yields... ; 2) and Through the suzuki reaction, we obtain ; 3) It undergoes a substitution reaction with (CF3SO2)2O to give ; 4) Reaction with ethyl mercaptopropionate yields ; 5) The ring-closure was carried out under alkaline catalysis to obtain... .

8. A liquid crystal composition, characterized in that, The liquid crystal composition contains the liquid crystal compound according to any one of claims 1 to 5.

9. The liquid crystal composition according to claim 8, characterized in that, The liquid crystal compound is present in the liquid crystal composition at a mass percentage of 0.01 to 60%.

10. The liquid crystal composition according to claim 9, characterized in that, The liquid crystal compound is present in the liquid crystal composition at a mass percentage of 0.1% to 50%.

11. The liquid crystal composition according to claim 10, characterized in that, The liquid crystal compound is present in the liquid crystal composition at a mass percentage of 0.1-40%.

12. The use of the liquid crystal compound according to any one of claims 1 to 5 or the liquid crystal composition according to any one of claims 8 to 11 in the field of liquid crystal displays.

13. The application according to claim 12, characterized in that, The application of the liquid crystal compound or the liquid crystal composition in a liquid crystal display device.

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