Liquid crystal compound, preparation method therefor and use thereof

Abstract

The present invention relates to the technical field of liquid crystal display, and provides a liquid crystal compound, a preparation method therefor and a use thereof. The liquid crystal compound has a structure as shown in general formula I. The liquid crystal compound provided by the present invention has a large negative dielectric anisotropy and a moderate rotational viscosity, and can effectively reduce the driving voltage of a liquid crystal display device to which the liquid crystal compound is applied, improve the response speed of the liquid crystal display device, and enable the liquid crystal display device to have a moderate optical anisotropy and a high charge retention rate.

Description

A liquid crystal compound, its preparation method and application

[0001] Cross-references

[0002] This application claims priority to Chinese Patent Application No. 202411057796.4, filed on August 2, 2024, entitled “A liquid crystal composition and its preparation method and application,” the entire disclosure of which is incorporated herein by reference. Technical Field

[0003] This invention belongs to the field of liquid crystal display technology, and particularly relates to a liquid crystal compound, its preparation method, and its application. Background Technology

[0004] 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. Currently, the development direction of LCD display devices, taking televisions as an example, aims for lightweight design, small footprint, and easy portability.

[0005] Liquid crystal materials, as environmentally friendly materials, have significant research value and promising prospects in fields such as information display materials and organic optoelectronic materials. Currently, thin-film transistor liquid crystal display (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 requirements for display technology continue to increase. For example, liquid crystal displays are required to achieve faster response times and lower driving voltages to reduce power consumption. This necessitates that liquid crystal materials possess characteristics such as 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 liquid crystal materials and adapt them to new requirements, more new liquid crystal compounds still need to be developed. Summary of the Invention

[0007] To address the shortcomings of existing technologies, the present invention aims to provide a liquid crystal compound, its preparation method, and its applications. This liquid crystal compound exhibits significant negative dielectric anisotropy and moderate rotational viscosity, which helps to reduce the driving voltage of liquid crystal display devices and improve response speed.

[0008] To achieve this objective, the present invention adopts the following technical solution:

[0009] In a first aspect, the present invention provides a liquid crystal compound having a structure as shown in general formula I:

[0010] R1 is selected from H, 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, and a cycloalkyl group having 3 to 5 carbon atoms.

[0011] R2 is selected from one of the following: alkyl group having 1 to 10 carbon atoms, alkenyl group having 2 to 10 carbon atoms, alkoxy group having 1 to 10 carbon atoms, alkenyl group having 2 to 10 carbon atoms, alkyl group having 1 to 10 carbon atoms substituted with F, alkenyl group having 2 to 10 carbon atoms substituted with F, alkoxy group having 1 to 10 carbon atoms substituted with F, alkenyl group having 2 to 10 carbon atoms substituted with F, and alkoxy group having 1 to 10 carbon atoms substituted with C3-C5 cycloalkyl group.

[0012] Z is selected from one of the following: single bond, -CH2-, -CH2CH2-, -CH2O-, and -CF2O-.

[0013] In this invention, the alkyl group having 1 to 10 carbon atoms can have 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 carbon atoms. The alkyl group can be a straight-chain alkyl group or a branched-chain alkyl group, preferably a straight-chain alkyl group.

[0014] The number of carbon atoms in the alkoxy group having 1 to 10 carbon atoms can be 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10. The alkoxy group can be a straight-chain alkoxy group or a branched-chain alkoxy group, preferably a straight-chain alkoxy group.

[0015] The F-substituted alkyl group having 1 to 10 carbon atoms can have 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 carbon atoms. The F-substituted alkyl group can be linear or branched, preferably linear.

[0016] The number of carbon atoms in the alkoxy group substituted with F, having 1 to 10 carbon atoms, can be 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10. The alkoxy group substituted with F can be linear or branched, preferably linear.

[0017] The cycloalkyl group having 3 to 5 carbon atoms refers to cyclopropyl, cyclobutyl, or cyclopentyl.

[0018] The alkenyl group having 2 to 10 carbon atoms can have 2, 3, 4, 5, 6, 7, 8, 9, or 10 carbon atoms. The alkenyl group can be a straight-chain alkenyl group or a branched alkenyl group, preferably a straight-chain alkenyl group. The carbon-carbon double bond can be located at any position in the group, preferably at the end. As a non-limiting example, the alkenyl group having 2 to 10 carbon atoms can be -CH=CH2, -CH2-CH=CH2, -(CH2)2-CH=CH2, -(CH2)3-CH=CH2, etc.

[0019] The number of carbon atoms in the olefinic group having 2 to 10 carbon atoms can be 2, 3, 4, 5, 6, 7, 8, 9, or 10. The olefinic group can be a straight-chain olefinic group or a branched-chain olefinic group, preferably a straight-chain olefinic group. The carbon-carbon double bond can be located at any position in the group, preferably at the end. As a non-limiting example, the olefinic group having 2 to 10 carbon atoms can be -O-CH=CH2, -O-CH2-CH=CH2, -O-(CH2)2-CH=CH2, -O-(CH2)3-CH=CH2, etc.

[0020] The number of carbon atoms in the alkenyl group with 2 to 10 carbon atoms substituted by F can be 2, 3, 4, 5, 6, 7, 8, 9 or 10.

[0021] The number of carbon atoms in the olefinic group that is replaced by F and has 2 to 10 carbon atoms can be 2, 3, 4, 5, 6, 7, 8, 9 or 10.

[0022] The alkoxy group having 1 to 10 carbon atoms substituted with a C3-C5 cycloalkyl group refers to a group formed by replacing at least one H atom of an alkoxy group having 1 to 10 carbon atoms with a C3-C5 cycloalkyl group. Here, C3-C5 cycloalkyl refers to a cycloalkyl group having 3 to 5 carbon atoms, namely cyclopropyl, cyclobutyl, or cyclopentyl; the meaning of alkoxy group having 1 to 10 carbon atoms is as described above. Preferably, the C3-C5 cycloalkyl group is substituted by one carbon atom, and the substitution site is preferably located at the end of the alkoxy group.

[0023] In this invention, unless otherwise specified, "replaced by F" means that at least one H atom in the group is replaced by an F atom, preferably at the end. For example, an alkoxy group with three carbon atoms substituted with three F atoms has the structure -O-CH2-CH2-CF3, and an alkoxy group with three carbon atoms substituted with two F atoms has the structure -O-CH2-CH=CF2.

[0024] In this invention, unless otherwise specified, the number of carbon atoms n in the B group with n carbon atoms substituted by A refers to the number of carbon atoms in the unsubstituted B group, and not the total number of carbon atoms in the substituted group.

[0025] In some embodiments of the present invention, R1 is selected from H, alkyl groups having 1 to 6 carbon atoms, alkoxy groups having 1 to 6 carbon atoms, alkyl groups having 1 to 6 carbon atoms substituted with F, alkoxy groups having 1 to 6 carbon atoms substituted with F, and cycloalkyl groups having 3 to 5 carbon atoms.

[0026] In some embodiments of the present invention, R1 is selected from H, alkyl groups having 1 to 6 carbon atoms, and cycloalkyl groups having 3 to 5 carbon atoms.

[0027] In some embodiments of the present invention, R2 is selected from alkyl groups having 1 to 5 carbon atoms, alkenyl groups having 2 to 5 carbon atoms, alkoxy groups having 1 to 5 carbon atoms, alkenyl groups having 2 to 5 carbon atoms, alkyl groups having 1 to 5 carbon atoms substituted with F, alkenyl groups having 2 to 5 carbon atoms substituted with F, alkoxy groups having 1 to 5 carbon atoms substituted with F, alkenyl groups having 2 to 5 carbon atoms substituted with F, and alkoxy groups having 1 to 5 carbon atoms substituted with C3-C5 cycloalkyl groups.

[0028] In some embodiments of the present invention, R2 is selected from one of an alkoxy group having 1 to 5 carbon atoms, an alkenoxy group having 2 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms substituted with F, an alkenoxy group having 2 to 5 carbon atoms substituted with F, and an alkoxy group having 1 to 5 carbon atoms substituted with C3-C5 cycloalkyl groups.

[0029] In some embodiments of the present invention, Z is selected from one of a single bond, -CH2-, -CH2CH2- and -CH2O-, preferably a single bond or -CH2O-.

[0030] In some embodiments of the present invention, the liquid crystal compound is selected from any one of the following compounds:

[0031] In a second aspect, the present invention provides a method for preparing a liquid crystal compound as described in the first aspect, the method comprising the following steps:

[0032] (1) Raw material I was subjected to a substitution reaction with borate ester in the presence of an organolithium reagent to obtain compound 1;

[0033] (2) Raw material II reacts with compound 1 via a suzuki reaction to obtain compound 2;

[0034] (3) Compound 2 undergoes a substitution reaction with trifluoromethanesulfonic anhydride ((CF3SO2)2O) to give compound 3;

[0035] (4) Compound 3 reacts with ethyl mercaptopropionate to give compound 4;

[0036] (5) Compound 4 undergoes a ring-closing reaction under alkaline catalysis to obtain the liquid crystal compound.

[0037] The preparation method provided by this invention can stably and efficiently obtain the liquid crystal compound described in this invention.

[0038] In some embodiments of the present invention, the preparation method further includes post-processing of the crude product of the liquid crystal compound.

[0039] In this invention, the post-processing can be a conventional post-processing step, exemplified as follows:

[0040] The crude product of the liquid crystal compound was extracted with dichloromethane, ethyl acetate or toluene, then separated, washed with water, dried, evaporated in a vacuum rotary evaporator, and the resulting product was purified by vacuum distillation or recrystallization and / or chromatographic separation to obtain a pure liquid crystal compound.

[0041] Thirdly, the present invention provides a liquid crystal composition comprising the liquid crystal compound as described in the first aspect.

[0042] In some embodiments of the present invention, the liquid crystal compound is present in the liquid crystal composition at a mass percentage of 0.01-60%, for example, 0.01%, 0.05%, 0.1%, 0.5%, 1%, 3%, 5%, 8%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, or 60%, etc.; preferably 0.1-50%. However, the present invention is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0043] Fourthly, the present invention provides the use of a liquid crystal compound as described in the first aspect, or a liquid crystal composition as described in the third aspect, in a liquid crystal display.

[0044] Fifthly, the present invention provides the use of a liquid crystal compound as described in the first aspect, or a liquid crystal composition as described in the third aspect, in a liquid crystal display device.

[0045] In this invention, the liquid crystal display device includes, but is not limited to, VA (Vertical Alignment) liquid crystal displays, TN (Twisted Nematic) liquid crystal displays, STN (Super-twisted Nematic) liquid crystal displays, FFS (Fringing Field Switching) liquid crystal displays, and IPS (In Plane Switching) liquid crystal displays.

[0046] Compared with the prior art, the present invention has the following beneficial effects:

[0047] (1) The liquid crystal compound provided by the present invention has a large negative dielectric anisotropy and a moderate rotational viscosity;

[0048] (2) The liquid crystal display device using the liquid crystal compound provided in this disclosure can effectively reduce the driving voltage and improve its response speed, while having the characteristics of moderate optical anisotropy and high charge retention rate. Detailed Implementation

[0049] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the specific embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention.

[0050] Unless otherwise specified, the raw materials used in the following embodiments are all available from commercial or other public sources.

[0051] Example 1

[0052] This embodiment provides a liquid crystal compound and its preparation method. The structural formula of the liquid crystal compound is as follows:

[0053] The synthesis route is as follows:

[0054] The synthesis steps are as follows:

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

[0056] Under nitrogen protection, 59.5 g (0.25 mol) of raw material I and 150 mL of tetrahydrofuran were added to the reaction flask. The temperature was controlled at -70 to -80 °C and 0.27 mol of n-butyllithium in n-hexane was added dropwise. After the addition was completed, the temperature was controlled at -60 to -70 °C and 41.6 g of trimethyl borate (0.4 mol) was added dropwise. Then the temperature was allowed to return to -30 °C naturally.

[0057] The mixture was acidified with 400 mL of 2M hydrochloric acid aqueous solution, and after routine post-treatment, it was recrystallized from petroleum ether to give 63 g of a light yellow solid (compound BYLC-01-1, 0.225 mol), HPLC: 99.7%, yield: 90%.

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

[0059] Under nitrogen protection, 63 g of compound BYLC-01-1 (0.225 mol), 59.2 g of starting material II (0.225 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 to a reaction flask. The mixture was heated to 70 °C and reacted for 3 hours. After routine post-treatment, the mixture was purified by chromatography, eluted with n-hexane, and recrystallized from ethanol to give 84 g of a white solid (compound BYLC-01-2, 0.2 mol), GC: 99.8%, yield: 89%.

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

[0061] 84 g of compound BYLC-01-2 (0.2 mol), 23.4 g of pyridine, 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 (0.3 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 99.5 g of a white solid (compound BYLC-01-3, 0.18 mol), GC: 99.8%, yield: 90%.

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

[0063] Under nitrogen protection, 99.5 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-dicyclohexylphosphine-2,4,6-triisopropylbiphenyl, 0.7 g of tris(dibenzylacetone)dipalladium, and 280 mL of dioxane were added to a reaction flask. The reaction was carried out at 100℃~105℃ for 6 hours. After routine post-treatment, the mixture was purified by chromatography and eluted with n-hexane to give a pale yellow liquid (75.1 g, 0.14 mol of compound BYLC-01-4), GC: 95.8%, yield: 77.8%.

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

[0065] Under nitrogen protection, 75.1 g of compound BYLC-01-4 (0.14 mol), 200 mL of N,N-dimethylformamide, and 38 g of potassium tert-butoxide were added to a reaction flask. The reaction was carried out at 130-140 °C for 3 hours, and the reaction was monitored by TLC until complete. After routine post-treatment, the product was purified by chromatography, eluted with n-hexane, and recrystallized from ethanol to give 34.9 g of a white solid (compound BYLC-01, 0.084 mol), GC: 99.9%, yield 60%.

[0066] The obtained white solid BYLC-01 was analyzed by GC-MS, and the m / z of the product was 416 (M+).

[0067] Example 2

[0068] This embodiment provides a liquid crystal compound and its preparation method. The structural formula of the liquid crystal compound is as follows:

[0069] The preparation method is the same as in Example 1, except that the corresponding raw material I and raw material II are replaced.

[0070] The obtained white solid BYLC-02 was analyzed by GC-MS, and the m / z of the product was 360 (M+).

[0071] Example 3

[0072] This embodiment provides a liquid crystal compound and its preparation method. The structural formula of the liquid crystal compound is as follows:

[0073] The preparation method is the same as in Example 1, except that the corresponding raw material I and raw material II are replaced.

[0074] The obtained white solid BYLC-03 was analyzed by GC-MS, and the m / z of the product was 388 (M+).

[0075] Example 4

[0076] This embodiment provides a liquid crystal compound and its preparation method. The structural formula of the liquid crystal compound is as follows:

[0077] The preparation method is the same as in Example 1, except that the corresponding raw material I and raw material II are replaced.

[0078] The obtained white solid BYLC-04 was analyzed by GC-MS, and the m / z of the product was 430 (M+).

[0079] Example 5

[0080] This embodiment provides a liquid crystal compound and its preparation method. The structural formula of the liquid crystal compound is as follows:

[0081] The preparation method is the same as in Example 1, except that the corresponding raw material I and raw material II are replaced.

[0082] The obtained white solid BYLC-05 was analyzed by GC-MS, and the m / z of the product was 402 (M+).

[0083] Example 6

[0084] This embodiment provides a liquid crystal compound and its preparation method. The structural formula of the liquid crystal compound is as follows:

[0085] The preparation method is the same as in Example 1, except that the corresponding raw material I and raw material II are replaced.

[0086] The obtained white solid BYLC-06 was analyzed by GC-MS, and the m / z of the product was 414 (M+).

[0087] Example 7

[0088] This embodiment provides a liquid crystal compound and its preparation method. The structural formula of the liquid crystal compound is as follows:

[0089] The preparation method is the same as in Example 1, except that the corresponding raw material I and raw material II are replaced.

[0090] The obtained white solid BYLC-07 was analyzed by GC-MS, and the m / z of the product was 414 (M+).

[0091] Example 8

[0092] This embodiment provides a liquid crystal compound and its preparation method. The structural formula of the liquid crystal compound is as follows:

[0093] The preparation method is the same as in Example 1, except that the corresponding raw material I and raw material II are replaced.

[0094] The obtained white solid BYLC-08 was analyzed by GC-MS, and the m / z of the product was 414 (M+).

[0095] Example 9

[0096] This embodiment provides a liquid crystal compound and its preparation method. The structural formula of the liquid crystal compound is as follows:

[0097] The preparation method is the same as in Example 1, except that the corresponding raw material I and raw material II are replaced.

[0098] The obtained white solid BYLC-09 was analyzed by GC-MS, and the m / z of the product was 400 (M+).

[0099] Example 10

[0100] This embodiment provides a liquid crystal compound and its preparation method. The structural formula of the liquid crystal compound is as follows:

[0101] The preparation method is the same as in Example 1, except that the corresponding raw material I and raw material II are replaced.

[0102] The obtained white solid BYLC-10 was analyzed by GC-MS, and the m / z of the product was 358 (M+).

[0103] Example 11

[0104] This embodiment provides a liquid crystal compound and its preparation method. The structural formula of the liquid crystal compound is as follows:

[0105] The preparation method is the same as in Example 1, except that the corresponding raw material I and raw material II are replaced.

[0106] The obtained white solid BYLC-11 was analyzed by GC-MS, and the m / z of the product was 330 (M+).

[0107] Example 12

[0108] This embodiment provides a liquid crystal compound and its preparation method. The structural formula of the liquid crystal compound is as follows:

[0109] The preparation method is the same as in Example 1, except that the corresponding raw material I and raw material II are replaced.

[0110] The obtained white solid BYLC-12 was analyzed by GC-MS, and the m / z of the product was 370 (M+).

[0111] Example 13

[0112] This embodiment provides a liquid crystal compound and its preparation method. The structural formula of the liquid crystal compound is as follows:

[0113] The preparation method is the same as in Example 1, except that the corresponding raw material I and raw material II are replaced.

[0114] The obtained white solid BYLC-13 was analyzed by GC-MS, and the m / z of the product was 356 (M+).

[0115] Example 14

[0116] This embodiment provides a liquid crystal compound and its preparation method. The structural formula of the liquid crystal compound is as follows:

[0117] The preparation method is the same as in Example 1, except that the corresponding raw material I and raw material II are replaced.

[0118] The obtained white solid BYLC-14 was analyzed by GC-MS, and the m / z of the product was 386 (M+).

[0119] Example 15

[0120] This embodiment provides a liquid crystal compound and its preparation method. The structural formula of the liquid crystal compound is as follows:

[0121] The preparation method is the same as in Example 1, except that the corresponding raw material I and raw material II are replaced.

[0122] The obtained white solid BYLC-15 was analyzed by GC-MS, and the m / z of the product was 400 (M+).

[0123] Example 16

[0124] This embodiment provides a liquid crystal compound and its preparation method. The structural formula of the liquid crystal compound is as follows:

[0125] The preparation method is the same as in Example 1, except that the corresponding raw material I and raw material II are replaced.

[0126] The obtained white solid BYLC-16 was analyzed by GC-MS, and the m / z of the product was 392 (M+).

[0127] Example 17

[0128] This embodiment provides a liquid crystal compound and its preparation method. The structural formula of the liquid crystal compound is as follows:

[0129] The preparation method is the same as in Example 1, except that the corresponding raw material I and raw material II are replaced.

[0130] The obtained white solid BYLC-17 was analyzed by GC-MS, and the m / z of the product was 422 (M+).

[0131] Comparative Example 1

[0132] This comparative example provides a liquid crystal compound with the following structural formula:

[0133] Performance testing:

[0134] The performance of the liquid crystal compounds provided in the examples and comparative examples was tested using the following methods:

[0135] (1) γ1: Measured using a viscometer;

[0136] (2) Δn: Measured using an Abbe refractometer;

[0137] (3) Δε: Tested using an INSTEC liquid crystal testing instrument;

[0138] The performance parameters of the liquid crystal compound were obtained through linear fitting, and the specific meanings of each performance parameter are as follows:

[0139] Δn represents optical anisotropy (25℃); Δε represents dielectric anisotropy (25℃, 1000Hz); γ1 represents rotational viscosity (mPa·s, 25℃).

[0140] The results of the above performance tests are shown in Table 1.

[0141] Table 1

[0142] As can be seen from the performance data in Table 1, compared with the existing compound CP-1, the liquid crystal compound provided in this embodiment of the invention has a larger negative dielectric anisotropy and a lower rotational viscosity, which can effectively reduce the driving voltage of the liquid crystal display device using it and improve the response speed of the liquid crystal display device.

[0143] The above description is merely a specific embodiment of this disclosure, enabling those skilled in the art to understand or implement it. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this disclosure. Therefore, this disclosure is not to be limited to the embodiments described herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A liquid crystal compound, characterized by, The liquid crystal compound has a structure as shown in general formula I: 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, and cycloalkyl having 3-5 carbon atoms; 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, alkenyl having 2-10 carbon atoms substituted by F, alkoxy having 1-10 carbon atoms substituted by F, alkenyloxy having 2-10 carbon atoms substituted by F, and alkoxy having 1-10 carbon atoms substituted by C3-C5 cycloalkyl; Z is selected from a single bond, -CH2-, -CH2CH2-, -CH2O-, and -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, and cycloalkyl having 3-5 carbon atoms.

3. The liquid crystal compound according to claim 1 or 2, characterized by 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, alkenyl having 2-5 carbon atoms substituted by F, alkoxy having 1-5 carbon atoms substituted by F, alkenyloxy having 2-5 carbon atoms substituted by F, and alkoxy having 1-5 carbon atoms substituted by C3-C5 cycloalkyl.

4. The liquid crystal compound according to any one of claims 1 to 3, characterized by Z is selected from a single bond, -CH2-, -CH2CH2-, and -CH2O-, preferably a single bond or -CH2O-.

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

6. A process for the preparation of a liquid crystal compound according to any one of claims 1 to 5, characterized in that, The preparation method comprises the following steps: (1) substituting raw material I with borate in the presence of organic lithium reagent to obtain compound 1; (2) subjecting raw material II to Suzuki reaction with compound 1 to obtain compound 2; (3) substituting compound 2 with trifluoromethanesulfonic anhydride to obtain compound 3; (4) subjecting compound 3 to reaction with mercaptopropionic acid ethyl ester to obtain compound 4; (5) subjecting compound 4 to ring closing reaction under catalysis of base to obtain the liquid crystal compound.

7. A liquid crystal composition, characterized by comprising The liquid crystal composition comprises the liquid crystal compound according to any one of claims 1-5.

8. The liquid crystal composition according to claim 7, characterized by The mass percentage of the liquid crystal compound in the liquid crystal composition is 0.01-60%, preferably 0.1-50%.

9. The liquid crystal compound according to any one of claims 1-5, or the liquid crystal composition according to claim 7 or 8, for use in liquid crystal display.

10. The liquid crystal compound according to any one of claims 1-5, or the liquid crystal composition according to claim 7 or 8, for use in liquid crystal display device.

Images