Liquid crystal compound, preparation method therefor and use thereof

Abstract

The present disclosure relates to a liquid crystal compound, a preparation method therefor, and a use thereof. The liquid crystal compound provided by the present disclosure has relatively large negative dielectric anisotropy and the characteristics of high clearing point, relatively high optical anisotropy, moderate rotational viscosity, and liquid crystal miscibility, exhibits excellent low-temperature working effect, and shows good properties such as thermal stability, chemical stability, optical stability, and mechanical properties. Therefore, the driving voltage of a liquid crystal display device in which the liquid crystal compound is used can be effectively reduced, the response speed of the liquid crystal display device is increased, and the liquid crystal display device has the characteristics of moderate optical anisotropy numerical value, high charge retention rate, etc.

Description

A liquid crystal compound and a preparation method and application thereof

[0001] Cross-reference to related applications

[0002] This application claims priority to Chinese Patent Application No. 202410618626.2 entitled "A liquid crystal compound and a preparation method and application thereof" filed on May 17, 2024, the entire disclosure of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0003] The present disclosure relates to the technical field of liquid crystal materials, and in particular to a liquid crystal compound and a preparation method and application thereof. BACKGROUND

[0004] In recent years, liquid crystal display devices have developed rapidly, and different types have also been developed, such as small liquid crystal display devices for vehicles, portable liquid crystal display devices, and ultra-thin liquid crystal display devices. At present, the development direction of liquid crystal display devices is exemplified by televisions, which aim to be light in weight, small in space occupied, and easy to move. There are also notebook personal computers, mobile phones, and the like.

[0005] Liquid crystal materials as environmental materials have great research value and prospect in the fields of information display materials and organic optoelectronic materials. At present, TFT-LCD (Thin Film Transistor Liquid Crystal Display) product technology has matured, successfully solving technical problems such as viewing angle, resolution, color saturation, and brightness. Large-size and small-size TFT-LCD displays have gradually occupied the mainstream position of flat panel displays in their respective fields. However, the requirements for display technology are constantly improving, requiring liquid crystal displays to achieve faster response, lower driving voltage to reduce power consumption, and the like, i.e., requiring liquid crystal materials to have low-voltage driving, fast response, wide temperature range, and good low-temperature stability.

[0006] Liquid crystal materials themselves play an important role in improving the performance of liquid crystal displays. In order to improve the performance of materials to adapt to new requirements, the synthesis of new structural liquid crystal compounds and the study of structure-property relationships have become an important work in the field of liquid crystals. SUMMARY

[0007] To solve the above technical problems, the present disclosure provides a liquid crystal compound and a preparation method and application thereof.

[0008] In a first aspect, the present disclosure provides a liquid crystal compound, which has a structural formula as shown in general formula I:

[0009] wherein:

[0010] R1is selected from H, alkyl having 1 to 10 carbon atoms, alkoxy having 1 to 10 carbon atoms, alkyl having 1 to 10 carbon atoms substituted by F, alkoxy having 1 to 10 carbon atoms substituted by F, cyclopropyl, cyclobutyl or cyclopentyl;

[0011] R2is selected from alkyl having 1 to 10 carbon atoms, alkenyl having 2 to 10 carbon atoms, alkoxy having 1 to 10 carbon atoms, alkenyloxy having 2 to 10 carbon atoms, alkyl having 1 to 10 carbon atoms substituted by F, alkoxy having 1 to 10 carbon atoms substituted by F, alkenyloxy having 2 to 10 carbon atoms substituted by F, alkoxy having 1 to 10 carbon atoms substituted by cyclopropyl, cyclobutyl or cyclopentyl;

[0012] Z1is selected from a single bond, -CH2-, -CH2CH2-, -CH2O- or -CF2O-, in the present disclosure, a single bond can also be understood as Z1is absent.

[0013] As a preferred technical solution of the present disclosure, R1is selected from H, alkyl having 1 to 6 carbon atoms, alkoxy having 1 to 6 carbon atoms, alkyl having 1 to 6 carbon atoms substituted by F, alkoxy having 1 to 6 carbon atoms substituted by F, cyclopropyl, cyclobutyl or cyclopentyl;

[0014] R2is selected from alkyl having 1 to 5 carbon atoms, alkenyl having 2 to 5 carbon atoms, alkoxy having 1 to 5 carbon atoms, alkenyloxy having 2 to 5 carbon atoms, alkyl having 1 to 5 carbon atoms substituted by F, alkoxy having 1 to 5 carbon atoms substituted by F, alkenyloxy having 2 to 5 carbon atoms substituted by F, alkoxy having 1 to 5 carbon atoms substituted by cyclopropyl, cyclobutyl or cyclopentyl;

[0015] Z1is selected from a single bond, -CH2-, -CH2CH2- or -CH2O-.

[0016] As a preferred technical solution of the present disclosure, Z1is selected from a single bond or -CH2O-.

[0017] As a preferred technical solution of the present disclosure, R1is selected from H, alkyl having 1 to 6 carbon atoms, cyclobutyl or cyclopentyl.

[0018] As a preferred technical solution of the present disclosure, the alkyl having 1 to 6 carbon atoms is methyl, ethyl, propyl, butyl, pentyl or hexyl.

[0019] As a preferred technical solution of the present disclosure, the propyl, butyl, pentyl or hexyl is a straight-chain alkyl.

[0020] As a preferred technical solution of the present disclosure, R2 is selected from alkoxy having 1-5 carbon atoms, alkenyloxy having 2-5 carbon atoms, alkoxy having 1-5 carbon atoms substituted by F, alkenyloxy having 2-5 carbon atoms substituted by F, alkoxy having 1-5 carbon atoms substituted by cyclopropyl, cyclobutyl or cyclopentyl.

[0021] As a preferred technical solution of the present disclosure, the alkoxy having 1-5 carbon atoms is -OCH3, -OC2H5, -OC3H7, -OC4H9, -OC5H 11 .

[0022] As a preferred technical solution of the present disclosure, the -OC3H7, -OC4H9, -OC5H 11 are all linear alkoxy.

[0023] As a preferred technical solution of the present disclosure, the alkenyloxy having 2-5 carbon atoms is -O-CH=CH2, -O-CH2-CH=CH2, -O-C2H5-CH=CH2, -O-C3H6-CH=CH2.

[0024] As a preferred technical solution of the present disclosure, the -O-C2H5-CH=CH2, -O-C3H6-CH=CH2 are linear terminal alkenyl alkenyloxy.

[0025] As a preferred technical solution of the present disclosure, the substitution site of the substituent F in the alkoxy having 1-5 carbon atoms substituted by F is at the terminal group of the alkoxy, and an exemplary list is: the alkoxy structure of 3 carbon atoms substituted by 3 F is: -O-CH2-CH2-CF3.

[0026] As a preferred technical solution of the present disclosure, the substitution site of the substituent F in the alkenyloxy having 2-5 carbon atoms substituted by F is at the terminal alkenyl group of the alkenyloxy, and an exemplary list is: the alkenyloxy structure of 3 carbon atoms substituted by 3 F is: -O-CH2-CH=CF2.

[0027] As a preferred technical solution of the present disclosure, the substitution site of the substituent (cyclopropyl, cyclobutyl or cyclopentyl) in the alkoxy having 1-5 carbon atoms substituted by cyclopropyl, cyclobutyl or cyclopentyl is at the terminal group of the alkoxy, and no further detailed list is provided.

[0028] As a preferred technical solution of the present disclosure, the liquid crystal compound is selected from any one of the following compounds:

[0029] In a second aspect, the present disclosure provides a preparation method of the liquid crystal compound of the first aspect, the preparation method comprising the following steps:

[0030] (1) substituting the raw material I and borate in the presence of an organic lithium reagent to obtain compound 1;

[0031] (2) substituting compound 1 and raw material II through suzuki reaction to obtain compound 2;

[0032] (3) substituting compound 2 and trifluoromethanesulfonic anhydride ((CF3SO2)2O) to obtain compound 3;

[0033] (4) substituting compound 3 and ethyl mercaptopropionate to obtain compound 4;

[0034] (5) substituting compound 4 under the catalysis of a base to obtain the liquid crystal compound.

[0035] As a preferred technical solution of the present disclosure, the preparation method further comprises post-treatment of the preliminary product.

[0036] In the present disclosure, the post-treatment can be a conventional post-treatment step, and exemplary ones are listed as follows:

[0037] extracting, separating, washing with water, drying, evaporating with a vacuum rotary evaporator, and then purifying the obtained product through reduced pressure distillation or recrystallization and / or chromatographic separation.

[0038] The preparation method provided by the present disclosure can stably and efficiently obtain the liquid crystal compound of the present disclosure.

[0039] In a third aspect, the present disclosure provides a liquid crystal composition comprising the liquid crystal compound of the first aspect.

[0040] As a preferred technical solution of the present disclosure, the mass percentage of the liquid crystal compound in the total mass of the liquid crystal composition is 0.01-60%, for example, 0.05%, 0.1%, 0.5%, 1%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, etc.

[0041] As a preferred technical solution of the present disclosure, the mass percentage of the liquid crystal compound in the total mass of the liquid crystal composition is 0.1-50%.

[0042] In a fourth aspect, the present disclosure provides the liquid crystal compound of the first aspect or the liquid crystal composition of the third aspect for use in the field of liquid crystal display.

[0043] As a preferred technical solution of the present disclosure, the application is the application in the liquid crystal display device. The liquid crystal display device includes but is not limited to VA (Vertical Alignment), TN (Twisted Nematic), STN (Super-twisted Nematic), FFS (Fringing Field Switching) or IPS (In Plane Switching) liquid crystal display.

[0044] The technical solution provided by the embodiments of the present disclosure has the following advantages compared with the prior art:

[0045] (1) The liquid crystal compound provided by the present disclosure has a large negative dielectric anisotropy, and at the same time has high bright spots, relatively high optical anisotropy, moderate rotational viscosity and liquid crystal mutual solubility, excellent low-temperature working effect, and good thermal stability, chemical stability, optical stability and mechanical properties;

[0046] (2) The liquid crystal display device using the liquid crystal compound provided by the present disclosure can effectively reduce the driving voltage and improve the response speed, and has the characteristics of moderate optical anisotropy value, high charge retention rate, etc. DETAILED DESCRIPTION

[0047] In order to more clearly understand the above-mentioned purposes, features and advantages of the present disclosure, the solutions of the present disclosure will be further described below. It should be noted that the embodiments of the present disclosure and the features in the embodiments can be combined with each other without conflict.

[0048] In the following description, many specific details are set forth in order to provide a thorough understanding of the present disclosure, but the present disclosure can also be implemented in other ways different from those described herein; obviously, the embodiments in the specification are only some of the embodiments of the present disclosure, not all the embodiments.

[0049] In the following examples, if the raw materials are not specifically mentioned, they can be obtained from public commercial channels.

[0050] For the performance detection of the following liquid crystal material, the performance parameters of the liquid crystal compound are obtained by linear fitting according to the conventional detection method in the art, and the specific meanings of the performance parameters are as follows:

[0051] Δn represents optical anisotropy (25℃); Δε represents dielectric anisotropy (25℃, 1000 Hz); γ1 represents rotational viscosity (mPa-s, 25℃).

[0052] Example 1

[0053] The present example provides a liquid crystal compound and a preparation method thereof, and the structural formula is as follows:

[0054] The synthetic route is as follows:

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

[0056] Under nitrogen protection, 66.1 g (0.26 mol) of raw material I, 150 mL of tetrahydrofuran, and 0.28 mol of n-butyllithium in n-hexane were added into a reaction bottle, and the temperature was controlled at -70 to -80℃. After dropping, the reaction was controlled at -60 to -70℃ for 1 h, and then the temperature was naturally increased to -30℃.

[0057] 2M aqueous hydrochloric acid solution 400 mL was added for acidification, and the conventional post-treatment was carried out. Petroleum ether recrystallization obtained light yellow solid (compound BYLC-01-1, 0.234 mol) 69.7 g, HPLC: 99.7%, yield: 90%.

[0058] (2) Synthesis of compound BYLC-01-2:

[0059] Under nitrogen protection, 69.7 g of compound BYLC-01-1 (0.234 mol), 61.8 g of raw material II (0.235 mol), 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 tetrakis triphenylphosphine palladium were added into a reaction bottle, and heated to 70℃ for 3 h; the conventional post-treatment was carried out, and the chromatography purification was carried out with n-hexane elution and ethanol recrystallization to obtain white solid (compound BYLC-01-2, 0.2 mol) 87.3 g, GC: 99.8%, yield: 85.5%.

[0060] (3) Synthesis of compound BYLC-01-3:

[0061] Into a 500 mL three-necked flask was placed 87.3 g of compound BYLC-01-2 (0.2 mol), 23.4 g of pyridine and 180 mL of dichloromethane, and stirring was started. The flask was protected by nitrogen and the temperature was controlled at 5-10 °C. Then 85 g of (CF3SO2)2O (0.3 mol) was added dropwise. After the addition was completed, the reaction was allowed to proceed overnight. The reaction solution was washed twice with water (200 mL x 2), dried over anhydrous sodium sulfate, and passed through a 40 g silica gel column. The white solid (compound BYLC-01-3, 0.18 mol) was obtained by drying under vacuum, 102.3 g, GC: 99.8%, yield: 90%.

[0062] (4) Synthesis of compound BYLC-01-4

[0063] Into a reaction flask was placed 97 g of compound BYLC-01-4 (0.18 mol), 26 g of ethyl mercaptopropionate, 25.6 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 carried out at a temperature of 100 °C to 105 °C for 6 hours under nitrogen protection. The reaction was followed by conventional post-treatment and purification by chromatography using n-hexane as the eluent. The light yellow liquid (compound BYLC-01-4, 74.6 g, 0.135 mol) was obtained by recrystallization from ethanol, GC: 95.8%, yield: 75%.

[0064] (5) Synthesis of compound BYLC-01

[0065] Into a reaction flask was placed 74.6 g of compound BYLC-01-4 (0.135 mol), 200 mL of N,N-dimethylformamide, and 37 g of potassium tert-butoxide. The reaction was carried out at a temperature of 130-140 °C for 3 hours under nitrogen protection. The reaction was followed by conventional post-treatment and purification by chromatography using n-hexane as the eluent. The white solid (compound BYLC-01, 0.081 mol) was obtained by recrystallization from ethanol, GC: 99.9%, yield: 60%.

[0066] The white solid BYLC-01 was analyzed by GC-MS, and the m / z of the product was 432 (M+).

[0067] Example 2

[0068] This example provides a liquid crystal compound, which has the following structural formula:

[0069] The preparation method was as described in Example 1. The white solid BYLC-02 was analyzed by GC-MS, and the m / z of the product was 376 (M+).

[0070] Example 3

[0071] The present example provides a liquid crystal compound, the structural formula is as follows:

[0072] The preparation method refers to example 1, and the obtained white solid BYLC-03 is analyzed by GC-MS, and the m / z of the product is 404 (M+).

[0073] Example 4

[0074] The present example provides a liquid crystal compound, the structural formula is as follows:

[0075] The preparation method refers to example 1, and the obtained white solid BYLC-04 is analyzed by GC-MS, and the m / z of the product is 446 (M+).

[0076] Example 5

[0077] The present example provides a liquid crystal compound, the structural formula is as follows:

[0078] The preparation method refers to example 1, and the obtained white solid BYLC-05 is analyzed by GC-MS, and the m / z of the product is 418 (M+).

[0079] Example 6

[0080] The present example provides a liquid crystal compound, the structural formula is as follows:

[0081] The preparation method refers to example 1, and the obtained white solid BYLC-06 is analyzed by GC-MS, and the m / z of the product is 430 (M+).

[0082] Example 7

[0083] The present example provides a liquid crystal compound, the structural formula is as follows:

[0084] The preparation method refers to example 1, and the obtained white solid BYLC-07 is analyzed by GC-MS, and the m / z of the product is 430 (M+).

[0085] Example 8

[0086] The present example provides a liquid crystal compound, the structural formula is as follows:

[0087] The preparation method refers to example 1, and the obtained white solid BYLC-08 is analyzed by GC-MS, and the m / z of the product is 430 (M+).

[0088] Example 9

[0089] The present example provides a liquid crystal compound, having the following structural formula:

[0090] The preparation method refers to example 1, and the obtained white solid BYLC-09 is analyzed by GC-MS, and the m / z of the product is 416 (M+).

[0091] Example 10

[0092] The present example provides a liquid crystal compound, having the following structural formula:

[0093] The preparation method refers to example 1, and the obtained white solid BYLC-10 is analyzed by GC-MS, and the m / z of the product is 374 (M+).

[0094] Example 11

[0095] The present example provides a liquid crystal compound, having the following structural formula:

[0096] The preparation method refers to example 1, and the obtained white solid BYLC-11 is analyzed by GC-MS, and the m / z of the product is 346 (M+).

[0097] Example 12

[0098] The present example provides a liquid crystal compound, having the following structural formula:

[0099] The preparation method refers to example 1, and the obtained white solid BYLC-12 is analyzed by GC-MS, and the m / z of the product is 386 (M+).

[0100] Example 13

[0101] The present example provides a liquid crystal compound, having the following structural formula:

[0102] The preparation method refers to example 1, and the obtained white solid BYLC-13 is analyzed by GC-MS, and the m / z of the product is 372 (M+).

[0103] Example 14

[0104] The present example provides a liquid crystal compound, having the following structural formula:

[0105] The preparation method refers to example 1, and the obtained white solid BYLC-14 is analyzed by GC-MS, and the m / z of the product is 402 (M+).

[0106] Example 15

[0107] The present example provides a liquid crystal compound, the structural formula of which is as follows:

[0108] The preparation method is referred to Example 1, and the obtained white solid BYLC-15 is analyzed by GC-MS, and the m / z of the product is 416 (M+).

[0109] Comparative Example

[0110] The present comparative example provides a liquid crystal compound, the structural formula of which is as follows:

[0111] Performance test:

[0112] The liquid crystal compounds provided by the example and the comparative example are subjected to performance test, and the method is as follows:

[0113] (1) γ1: tested by a viscometer;

[0114] (2) Δn: tested by an Abbe refractometer;

[0115] (3) Δε: tested by an INSTEC liquid crystal detector;

[0116] The performance parameters of the liquid crystal compound are obtained by linear fitting, wherein the specific meanings of the performance parameters are as follows, and the results are shown in Table 1:

[0117] Δn represents optical anisotropy (25℃); Δε represents dielectric anisotropy (25℃, 1000 Hz); γ1 represents rotational viscosity (mPa·s, 25℃).

[0118] Table 1

[0119] It can be known from the performance test that the liquid crystal compound provided by the present disclosure has greater negative dielectric anisotropy and lower rotational viscosity.

[0120] It is to be noted that, in the present text, relational terms such as "first" and "second", and the like, are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual relationship or order between such entities or actions. Moreover, the terms "comprises", "comprising", or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element preceded by "comprises... " does not, without more constraints, foreclose the existence of additional identical elements in the process, method, article, or apparatus that comprises the recited element.

[0121] The above description is merely that of the specific implementations of the present disclosure, enabling a person skilled in the art to understand or implement the present disclosure. Various modifications to these implementations will be readily apparent to those skilled in the art, and the generic principles defined herein can be implemented in other implementations without departing from the spirit or scope of the present disclosure. Therefore, the present disclosure is not to be limited to the implementations described herein, but is to accord with the widest scope consistent with the principles and novel features disclosed herein. Industrial applicability

[0122] The present disclosure relates to a liquid crystal compound and a preparation method and application thereof. The liquid crystal compound provided by the present disclosure has a large negative dielectric anisotropy, and at the same time has the characteristics of high bright spot, relatively high optical anisotropy, moderate rotational viscosity and liquid crystal mutual solubility, and excellent low-temperature working effect, and has good thermal stability, chemical stability, optical stability and mechanical properties; thereby effectively reducing the driving voltage of a liquid crystal display device using the same, improving the response speed of the liquid crystal display device, and at the same time making the liquid crystal display device have the characteristics of moderate optical anisotropy value, high charge retention rate, etc.

Claims

1. A liquid crystal compound, characterized by, The liquid crystal compound has a structural formula as shown in general formula I: wherein: R1is selected from H, alkyl having 1-10 carbon atoms, alkoxy having 1-10 carbon atoms, alkyl having 1-10 carbon atoms substituted by F, alkoxy having 1-10 carbon atoms substituted by F, cyclopropyl, cyclobutyl or cyclopentyl; R2is selected from alkyl having 1-10 carbon atoms, alkenyl having 2-10 carbon atoms, alkoxy having 1-10 carbon atoms, alkenyloxy having 2-10 carbon atoms, alkyl having 1-10 carbon atoms substituted by F, alkoxy having 1-10 carbon atoms substituted by F, alkenyloxy having 2-10 carbon atoms substituted by F, alkoxy having 1-10 carbon atoms substituted by cyclopropyl, cyclobutyl or cyclopentyl; Z1is selected from a single bond, -CH2-, -CH2CH2-, -CH2O- or -CF2O-.

2. The liquid crystal compound according to claim 1, characterized by R1is selected from H, alkyl having 1-6 carbon atoms, alkoxy having 1-6 carbon atoms, alkyl having 1-6 carbon atoms substituted by F, alkoxy having 1-6 carbon atoms substituted by F, cyclopropyl, cyclobutyl or cyclopentyl; R2is selected from alkyl having 1-5 carbon atoms, alkenyl having 2-5 carbon atoms, alkoxy having 1-5 carbon atoms, alkenyloxy having 2-5 carbon atoms, alkyl having 1-5 carbon atoms substituted by F, alkoxy having 1-5 carbon atoms substituted by F, alkenyloxy having 2-5 carbon atoms substituted by F, alkoxy having 1-5 carbon atoms substituted by cyclopropyl, cyclobutyl or cyclopentyl; Z1is selected from a single bond, -CH2-, -CH2CH2- or -CH2O-.

3. The liquid crystal compound according to claim 2, characterized by Z1is selected from a single bond or -CH2O-.

4. The liquid crystal compound according to any one of claims 1 to 3, characterized by The liquid crystal compound is selected from any one of the following compounds:

5. The method of producing a liquid crystal compound according to any one of claims 1 to 4, characterized by, The preparation method comprises the following steps: (1) subjecting the starting material I and borate to a substitution reaction in the presence of an organic lithium reagent to obtain compound 1; (2) subjecting the starting material II to a Suzuki reaction with compound 1 to obtain compound 2; (3) subjecting compound 2 to a substitution reaction with trifluoromethanesulfonic anhydride to obtain compound 3; (4) subjecting compound 3 to a reaction with ethyl mercaptopropionate to obtain compound 4; (5) subjecting compound 4 to a ring-closing reaction under catalysis of a base to obtain the liquid crystal compound.

6. A liquid crystal composition, characterized by comprising The composition comprises the liquid crystal compound of any one of claims 1-4.

7. The liquid crystal composition according to claim 6, characterized by The mass percentage of the liquid crystal compound is 0.01-60% based on the total mass of the liquid crystal composition.

8. The liquid crystal composition according to claim 7, characterized by The mass percentage of the liquid crystal compound is 0.1-50% based on the total mass of the liquid crystal composition.

9. The liquid crystal compound of any one of claims 1-4, or the liquid crystal composition of any one of claims 6-8 for use in the field of liquid crystal display.

10. Use according to claim 9, characterized in that, The use is in the liquid crystal display device. The use is in the liquid crystal display device.

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