Liquid crystal compound, preparation method therefor and use thereof

Abstract

The present invention relates to the technical field of liquid crystal materials, and in particular, to a liquid crystal compound, a preparation method therefor and a use thereof. The structural formula of the liquid crystal compound is formula (I). The liquid crystal compound of the present invention has large negative dielectric anisotropy, and also has a high clearing point, relatively high optical anisotropy, moderate rotational viscosity and liquid crystal miscibility, excellent performance at low temperatures, and good performance in heat stability, chemical stability, optical stability, and mechanical properties, etc., thereby efficiently reducing a drive voltage and increasing the response speed of a liquid display device. Additionally, the liquid crystal compound has characteristics such as moderate optical anisotropy and high voltage holding ratio.

Description

Liquid crystal compound and its preparation method and application

[0001] Cross-references

[0002] This application claims priority to Chinese patent application No. 202310068509.9, filed on January 13, 2023, entitled “A Liquid Crystal Compound, Preparation Method and Application Thereof,” all disclosures of which are incorporated herein by reference in their entirety. Technical Field

[0003] The present invention belongs to the technical field of liquid crystal materials and relates to a liquid crystal compound and a preparation method and application thereof. Background Art

[0004] Liquid crystal display (LCD) devices have been developing rapidly in recent years, with a variety of types emerging, including small in-vehicle LCDs, portable LCDs, and ultra-thin LCDs. For example, in the case of televisions, LCDs are characterized by their light weight, compact footprint, and ease of mobility, as seen in laptop computers and mobile phones.

[0005] Liquid crystal materials, as environmental materials, hold immense research value and promising application prospects in fields such as information display materials and organic optoelectronics. Currently, TFT-LCD product technology has matured, successfully addressing technical challenges such as viewing angle, resolution, color saturation, and brightness. Large- and medium-sized TFT-LCD displays have gradually become mainstream flat-panel displays in their respective fields. However, the requirements for display technology continue to increase, with demands for faster response times, lower power consumption, a wide temperature range, and excellent low-temperature stability.

[0006] 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 new structural liquid crystal compounds and the study of structure-performance relationships have become an important task in the liquid crystal field.

[0007] In view of this, the present invention is proposed.

[0008] Summary of the Invention

[0009] The present invention provides a liquid crystal compound and a preparation method and application thereof, and improves the performance of a liquid crystal display device by designing a liquid crystal compound with a novel structure.

[0010] Specifically, the present invention provides a liquid crystal compound having the structural formula as described in general formula (I):

[0011] In the 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 by F, an alkoxy group having 1 to 10 carbon atoms substituted by F, a cyclopropyl group, a cyclobutyl group, or a cyclopentyl group;

[0012] 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 alkenyloxy group having 2 to 10 carbon atoms, an alkyl group having 1 to 10 carbon atoms substituted by F, an alkoxy group having 1 to 10 carbon atoms substituted by F, an alkenyloxy group having 2 to 10 carbon atoms substituted by F, or an alkoxy group having 1 to 10 carbon atoms substituted by cyclopropyl, cyclobutyl or cyclopentyl;

[0013] Z represents -CH2CH2O-, -CH2CH2CH2O- or -CH2CH2CH2CH2O-;

[0014] According to a liquid crystal compound provided by 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 by F, an alkoxy group having 1 to 6 carbon atoms substituted by F, a cyclopropyl group, a cyclobutyl group or a cyclopentyl group;

[0015] 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 alkenyloxy group having 2 to 5 carbon atoms, an alkyl group having 1 to 5 carbon atoms substituted by F, an alkoxy group having 1 to 5 carbon atoms substituted by F, an alkenyloxy group having 2 to 5 carbon atoms substituted by F, or an alkoxy group having 1 to 5 carbon atoms substituted by cyclopropyl, cyclobutyl or cyclopentyl

[0016] Z represents -CH2CH2O-, -CH2CH2CH2O- or -CH2CH2CH2CH2O-;

[0017] According to the present invention, a liquid crystal compound is provided, whose structural formula is any one of the following structural formulas:

[0018] The liquid crystal compound provided by the present invention has the structural formula:

[0019] or

[0020] The liquid crystal compound provided by the present invention has the structural formula:

[0021] The present invention also provides a method for preparing the liquid crystal compound as described above, and the synthesis route thereof is as follows:

[0022] The preparation method provided by the present invention comprises the following steps:

[0023] 1) Metalation reaction with organolithium reagent, followed by reaction with borate ester, yields

[0024] 2) and Through the Suzuki reaction, we can obtain

[0025] 3) Substitution reaction with (CF3SO2)2O yields

[0026] 4) Reaction with ethyl mercaptopropionate to obtain

[0027] 5) The ring closure is carried out under base catalysis to obtain

[0028] Wherein, R1, Z and R2 have the same meanings as those in the aforementioned part.

[0029] Preferably, in step 1) of the above method, The molar ratio of the organic lithium reagent to the organic lithium reagent is 1:1.0-2.0, and the molar ratio of the organic lithium reagent to the borate ester is 1:1.0-3.0;

[0030] Preferably, the reaction temperature can be between -50 and -100°C;

[0031] in, It can be obtained through public commercial channels; the organic lithium reagent is selected from one or more of sec-butyl lithium, tert-butyl lithium and n-butyl lithium; the borate ester is selected from one or more of trimethyl borate, triisopropyl borate, tributyl borate and triisobutyl borate.

[0032] In step 2) of the above method, and The feeding molar ratio is 1.0:1.0~1.5;

[0033] Preferably, the reaction temperature may be between 60 and 140°C;

[0034] Among them, raw materials Available through open commercial channels.

[0035] In step 3) of the above method, The molar ratio of (CF3SO2)2O is 1.0-2.0:2;

[0036] Preferably, the reaction temperature can be between 0 and 20°C;

[0037] In the step 4), The molar ratio of the raw material to ethyl mercaptopropionate is 1:1.0-2.0;

[0038] Preferably, the reaction temperature is 50-150°C.

[0039] In the step 5), The molar ratio of the feed to the alkali is 1:1.0 to 4.0;

[0040] Preferably, the reaction temperature is 80-150° C., and the base can be potassium tert-butoxide and / or sodium tert-butoxide.

[0041] The above preparation method can be used to obtain the liquid crystal compound of the present invention more stably and efficiently.

[0042] In the present invention, those skilled in the art can use conventional post-treatment methods according to actual needs when using the above-mentioned preparation method. Preferably, the conventional post-treatment includes: extraction with dichloromethane, ethyl acetate or toluene, separation, water washing, drying, evaporation on a vacuum rotary evaporator, and purification of the obtained product by reduced pressure distillation, recrystallization and / or chromatography.

[0043] The present invention also provides a liquid crystal composition containing the liquid crystal compound.

[0044] Preferably, the mass percentage of the liquid crystal compound in the liquid crystal composition is 0.01 to 60%;

[0045] It is more preferably 0.1 to 50%; further preferably 0.1 to 40%.

[0046] The present invention further provides the use of the above-mentioned liquid crystal compound or the above-mentioned liquid crystal composition in the field of liquid crystal display, preferably in a liquid crystal display device.

[0047] More preferably, the liquid crystal display device includes a VA, TN, STN, FFS or IPS liquid crystal display.

[0048] The present invention provides a liquid crystal compound, a preparation method, and an application thereof. By optimizing the structure, the liquid crystal compound has large dielectric anisotropy, high-definition bright spots, relatively high optical anisotropy, moderate rotational viscosity and liquid crystal miscibility, excellent low-temperature operation, and good thermal stability, chemical stability, optical stability, and mechanical properties. This effectively reduces the driving voltage and improves the response speed of the liquid crystal display device. The liquid crystal compound also has the characteristics of moderate optical anisotropy and high charge retention. DETAILED DESCRIPTION

[0049] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention are described clearly and completely below. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0050] If no specific techniques or conditions are specified in the examples, the experiments were carried out according to the techniques or conditions described in the literature in the field or according to the product instructions. If no manufacturer is specified for the reagents or instruments used, they are all conventional products that can be purchased through regular channels.

[0051] Example 1

[0052] A method for preparing a liquid crystal compound, wherein the liquid crystal compound has the structural formula:

[0053] The synthesis route of the liquid crystal compound is as follows:

[0054] The specific preparation steps of the liquid crystal compound are as follows:

[0055] (1) Synthesis of compound BYLC-01-1:

[0056] Under nitrogen protection, 73.6 g (0.261 mol) was added to the reaction bottle. To 150 ml of tetrahydrofuran, add dropwise a 0.45 mol solution of n-butyllithium in n-hexane at a temperature of -70 to -80°C. After completion of the addition, allow to react at a temperature of 1 hour. Then, add dropwise 48.0 g of trimethyl borate (0.45 mol) at a temperature of -60 to -70°C, and then naturally return the temperature to -30°C. Acidify with 400 ml of a 2 M aqueous hydrochloric acid solution. Following conventional post-treatment, recrystallize from petroleum ether to obtain 76.6 g of a light yellow solid (compound BYLC-01-1, 0.235 mol), HPLC: 99.5%, yield: 90%.

[0057] (2) Synthesis of compound BYLC-01-2:

[0058] Under nitrogen protection, 76.6g of compound BYLC-01-1 (0.235mol), 61.5g (0.235mol) of compound 200 ml of N,N-dimethylformamide, 100 ml of deionized water, 72.8 g of anhydrous potassium carbonate (0.53 mol), and 0.5 g of tetrakistriphenylphosphine palladium were heated to 70°C for 3 hours. Post-processing: chromatographic purification with n-hexane elution and recrystallization from ethanol afforded 92.8 g of a white solid (compound BYLC-01-2, 0.2 mol), GC: 99.8%, yield: 85%.

[0059] (3) Synthesis of compound BYLC-01-3:

[0060] To a 500ml three-necked flask, 92.8g of compound BYLC-01-2 (0.2mol), 0.3g of succinic acid, 13.4g of Et3N, and 180ml of dichloromethane were added. Stirring was initiated under nitrogen protection and the temperature was controlled at 5-10°C. 85g of (CF3SO2)2O (0.300mol) was added dropwise. The mixture was stirred overnight. The reaction mixture was washed twice with water (200ml x 2), dried over anhydrous sodium sulfate, and passed through a 40g silica gel column. The mixture was then dried to give 107.3g of a white solid (compound BYLC-01-3, 0.18mol). GC analysis indicated a 99.8% yield. The yield was 90%.

[0061] (4) Synthesis of compound BYLC-01-4

[0062] Under nitrogen, a reaction flask was charged with 107.3 g of compound BYLC-01-4 (0.18 mol), 28 g of ethyl mercaptopropionate, 26 g of N,N-diisopropylethylamine, 0.7 g of 2-dicyclohexylphosphino-2,4,6-triisopropylbiphenyl, 0.7 g of tris(dibenzylideneacetone)dipalladium, and 280 ml of dioxane. The reaction was maintained at 100°C to 105°C for 6 hours. Conventional post-treatment and purification by chromatography (eluting with n-hexane) afforded 83.6 g of a light yellow liquid (compound BYLC-01-4), with a GC yield of 95.8% and an 80% yield.

[0063] (5) Synthesis of compound BYLC-01:

[0064] Under nitrogen, 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 maintained at 130-140°C for 4 hours. TLC confirmed the reaction was complete. Conventional post-processing was performed, followed by chromatography, elution with n-hexane, and recrystallization from ethanol to afford 46 g of a white solid (compound BYLC-01, 0.1 mol). GC analysis indicated a 99.9% yield, yielding 70%.

[0065] The obtained white solid BYLC-01 was analyzed by GC-MS, and the m / z of the product was 460 (M+).

[0066] Example 2

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

[0068] The synthetic route of the compound shown in BYLC-02 is similar to that of Example 1, with the main difference being: Replace with

[0069] The obtained white solid BYLC-02 was analyzed by GC-MS, and the m / z of the product was 486 (M+).

[0070] Example 3

[0071] A method for preparing a liquid crystal compound, wherein the liquid crystal compound has the structural formula:

[0072] The synthetic route of the compound shown in BYLC-03 is similar to that of Example 1, with the main difference being: Replace with

[0073] The obtained white solid BYLC-03 was analyzed by GC-MS, and the m / z of the product was 458 (M+).

[0074] Example 4

[0075] A method for preparing a liquid crystal compound, wherein the liquid crystal compound has the structural formula:

[0076] The synthetic route of the compound shown in BYLC-04 is similar to that of Example 1, with the main difference being: Replace with

[0077] The obtained white solid BYLC-04 was analyzed by GC-MS, and the m / z of the product was 486 (M+).

[0078] Example 5

[0079] A method for preparing a liquid crystal compound, wherein the liquid crystal compound has the structural formula:

[0080] The synthetic route of the compound shown in BYLC-05 is similar to that of Example 1, with the main difference being: Replace with

[0081] The obtained white solid BYLC-05 was analyzed by GC-MS, and the m / z of the product was 474 (M+).

[0082] Example 6

[0083] A method for preparing a liquid crystal compound, wherein the liquid crystal compound has the structural formula:

[0084] The synthetic route of the compound shown in BYLC-06 is similar to that of Example 1, with the main difference being: Replace with

[0085] Will Replace with

[0086] The obtained white solid BYLC-06 was analyzed by GC-MS, and the m / z of the product was 500 (M+).

[0087] Example 7

[0088] A method for preparing a liquid crystal compound, wherein the liquid crystal compound has the structural formula:

[0089] The synthetic route of the compound shown in BYLC-07 is similar to that of Example 1, with the main difference being: Replace with

[0090] Will Replace with

[0091] The obtained white solid BYLC-07 was analyzed by GC-MS, and the m / z of the product was 472 (M+).

[0092] Example 8

[0093] A method for preparing a liquid crystal compound, wherein the liquid crystal compound has the structural formula:

[0094] The synthetic route of the compound shown in BYLC-08 is similar to that of Example 1, with the main difference being: Replace with

[0095] The obtained white solid BYLC-08 was analyzed by GC-MS, and the m / z of the product was 500 (M+).

[0096] Example 9

[0097] A method for preparing a liquid crystal compound, wherein the liquid crystal compound has the structural formula:

[0098] The synthetic route of the compound shown in BYLC-09 is similar to that of Example 1, with the main difference being: Replace with

[0099] The obtained white solid BYLC-09 was analyzed by GC-MS, and the m / z of the product was 488 (M+).

[0100] Example 10

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

[0102] The synthetic route of the compound shown in BYLC-10 is similar to that of Example 1, with the main difference being: Replace with

[0103] Will Replace with

[0104] The obtained white solid BYLC-12 was analyzed by GC-MS, and the m / z of the product was 514 (M+).

[0105] Example 11

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

[0107] The synthetic route of the compound shown in BYLC-11 is similar to that of Example 1, except that: Replace with

[0108] Will Replace with

[0109] The obtained white solid BYLC-13 was analyzed by GC-MS, and the m / z of the product was 486 (M+).

[0110] Example 12

[0111] A method for preparing a liquid crystal compound, wherein the liquid crystal compound has the structural formula:

[0112] The synthetic route of the compound shown in BYLC-12 is similar to that of Example 1, except that: Replace with

[0113] The obtained white solid BYLC-14 was analyzed by GC-MS, and the m / z of the product was 514 (M+).

[0114] Comparative Example

[0115] A method for preparing a compound having the following structural formula:

[0116] Experimental example

[0117] The performance parameters of the compounds prepared in the Examples and Comparative Examples were tested according to conventional testing methods in the art, such as γ1 using a viscometer, △n using an Abbe refractometer, and △ε using an INSTEC liquid crystal testing instrument. Various performance parameters of the liquid crystal compounds were obtained by linear fitting, where the specific meanings of the various performance parameters are as follows: △n represents optical anisotropy (25°C); △ε represents dielectric anisotropy (25°C, 1000 Hz); and γ1 represents rotational viscosity (mPa.s, 25°C). The test results are shown in the following table:

[0118] It can be seen from the above experimental data that the liquid crystal compound provided by the present invention has a larger negative dielectric anisotropy and a lower rotational viscosity.

[0119] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A liquid crystal compound, characterized in that, Has a structural formula as described by the 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, cyclopropyl, cyclobutyl or cyclopentyl; 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 alkenyloxy group having 2 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, an alkenyloxy group having 2 to 10 carbon atoms substituted with F, 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, wherein 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, cyclopropyl, cyclobutyl or cyclopentyl; 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 alkenyloxy 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 alkenyloxy group having 2 to 5 carbon atoms substituted with F, 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, wherein Its structural formula is any one of the following structural formulas:

4. The liquid crystal compound according to claim 3, wherein Its structural formula is as follows:

5. The liquid crystal compound according to claim 4, characterized in that, Its structural formula is as follows:

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, Comprising the following steps: 1) Place React with organolithium reagent for metallization reaction, and then react with borate ester to obtain 2) With Obtained via the Suzuki reaction 3) Obtained by substitution reaction with (CF3SO2)2O 4) React with ethyl 3-mercaptopropionate to obtain 5) Ring closure is carried out under base 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 mass percentage of the liquid crystal compound in the liquid crystal composition is 0.01 to 60%; preferably 0.1 to 50%; more preferably 0.1 to 40%.

10. Use of the liquid crystal compound according to any one of claims 1 to 5 or the liquid crystal composition according to claim 8 or 9 in the field of liquid crystal display, preferably in a liquid crystal display device.

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