Liquid crystal compound and application thereof

Abstract

The invention relates to a liquid crystal compound and application thereof. The liquid crystal compound provided by the invention has a structure as shown in the formula I, has a relatively long rigid main body structure, and can obviously improve the dielectric anisotropy of a liquid crystal material and improve the performance of the liquid crystal material.

Description

Technical Field

[0001] This invention relates to the field of liquid crystal materials technology, specifically to liquid crystal compounds and their applications. Background Technology

[0002] Liquid crystal materials are a class of special organic compounds that combine the fluidity of liquids with the optical anisotropy of crystals. They are the core functional materials for liquid crystal displays (LCDs) and many optoelectronic devices. The application of liquid crystal materials as environmental materials in information display materials, organic optoelectronic materials, and other fields has great research value and broad application prospects.

[0003] Liquid crystal materials themselves play a crucial role in improving the performance of liquid crystal displays (LCDs), especially reducing the rotational viscosity and increasing the dielectric anisotropy (Δε) of liquid crystal materials, which significantly improves LCD performance. Therefore, to improve the performance of liquid crystal materials and adapt them to new requirements, the synthesis of novel liquid crystal compounds and the study of structure-property relationships have become important work in the field of liquid crystals. Summary of the Invention

[0004] To address at least one of the aforementioned technical problems, this invention develops a novel dielectric anisotropic liquid crystal compound. This liquid crystal compound possesses excellent properties such as high dielectric anisotropy, good liquid crystal miscibility, and suitable rotational viscosity, and can be used to improve the performance of liquid crystal materials. Furthermore, this invention also provides a liquid crystal material composition comprising this liquid crystal compound, and the applications of this liquid crystal compound and the liquid crystal material composition.

[0005] In a first aspect, the present invention provides a liquid crystal compound having a structure as shown in Formula I: ;

[0006] Among them, X1 and X2 are each independently selected from CH2, O or S; R1 and R2 are each independently selected from any one or more combinations of halogenated or unsubstituted C1-C12 alkyl, halogenated or unsubstituted C1-C12 alkoxy, halogenated or unsubstituted C3-C10 cycloalkyl, halogenated or unsubstituted C2-C12 alkenyl, and halogenated or unsubstituted C2-C12 alkenyloxy. Ring A and ring B are each independently selected from any one or more combinations of halogenated or unsubstituted C6-C14 arylene, halogenated or unsubstituted C5-C8 cycloalkyl, halogenated or unsubstituted C5-C8 cycloalkenyl, and halogenated or unsubstituted C3-C8 saturated or unsaturated oxy-containing heterocyclic groups. Z1 and Z2 are each independently selected from any one or more combinations of single bonds, double bonds, -O-, C1-C4 alkylene, C1-C4 alkoxy, -COO-, -OCO-, -O-C1-C4 alkylene-O-, and C2-C4 alkenyl; optionally, one or more hydrogen atoms in the C1-C4 alkylene, C1-C4 alkoxy, and C2-C4 alkenyl groups are substituted with halogen atoms; m and n are each independently selected from 0, 1, or 2.

[0007] In this invention, the halogenated or unsubstituted alkyl group is preferably linear, where "linear" specifically means that all carbon atoms constituting the alkyl group are on the same carbon chain. The halogenated or unsubstituted alkyl group can make the anisotropic arrangement of the above-mentioned liquid crystal compound more ordered, thus enabling it to possess liquid crystal properties. "Liquid crystal properties" refers to the ability of a substance to exhibit the fluidity of a liquid and the anisotropic ordered arrangement of a crystalline substance at a certain temperature.

[0008] In this invention, the halogenated or unsubstituted alkoxy group can be considered as the structure formed by connecting the aforementioned halogenated or unsubstituted alkyl group to an oxygen atom (O). The halogenated or unsubstituted alkoxy group is also preferably linear, and the aforementioned liquid crystal compound containing a linear halogenated or unsubstituted alkoxy group can also exhibit good liquid crystal properties.

[0009] In this invention, the halogenated or unsubstituted alkenyl group can be a straight-chain alkenyl group or a branched alkenyl group, preferably a straight-chain alkenyl group. The above-mentioned liquid crystal compounds containing this halogenated or unsubstituted straight-chain alkenyl group are relatively easy to prepare and can exhibit good liquid crystal properties.

[0010] In this invention, the halogenated or unsubstituted alkenyloxy group can be a straight-chain alkenyloxy group or a branched alkenyloxy group, with a straight-chain alkenyloxy group being preferred. The halogenated or unsubstituted alkenyloxy group can be considered as a structure formed by the connection of a halogenated or unsubstituted alkenyl group to an oxygen atom.

[0011] The substituents of the present invention have a suitable number of carbon atoms, which makes it easier to prepare the liquid crystal compound shown in Formula I and to control its dielectric anisotropy values ​​over a wide range.

[0012] In this invention, unless otherwise specified, alkyl, alkoxy, alkenyl, and alkenyloxy groups are all linear chains.

[0013] In this invention, "halogenated..." means that any one or more hydrogen atoms in a group are replaced by halogen atoms, that is, the substituent in the group is a halogen atom. For example, haloalkyl specifically refers to an alkyl group replaced by a halogen atom. Similarly, other halogenated groups are treated the same way and will not be elaborated further. The introduction of halogen substituents can increase the dielectric anisotropy of the above-mentioned liquid crystal compounds, making the types of compounds more diverse. "Halogenated" can be partially halogenated or fully halogenated. "Fully halogenated" means that all hydrogen atoms in the above-mentioned group are replaced by halogen atoms. "Partially halogenated" means that some hydrogen atoms in the above-mentioned group are replaced by halogen atoms. The halogen atom can be one or more of fluorine (F), chlorine (Cl), bromine (Br), and iodine (I), with fluorine being the most common.

[0014] In a preferred embodiment of the present invention, each of the above-mentioned halogenated groups is specifically a corresponding fluorinated group, namely, a halogenated or unsubstituted C1-C12 alkyl group, a halogenated or unsubstituted C1-C12 alkoxy group, a halogenated or unsubstituted C3-C10 cycloalkyl group, a halogenated or unsubstituted C2-C12 alkenyl group, or a halogenated or unsubstituted C2-C12 alkenyl group. Preferably, the halogenated or unsubstituted C1-C12 alkyl group, a halogenated or unsubstituted C1-C12 alkoxy group, a halogenated or unsubstituted C3-C10 cycloalkyl group, a halogenated or unsubstituted C2-C12 alkenyl group, or a halogenated or unsubstituted C2-C12 alkenyl group is preferred, which is beneficial for the liquid crystal compound of Formula I to have a larger dielectric anisotropy value.

[0015] It should be noted that, in this invention, each fluorinated group refers to a group in which at least one (e.g., one, two, three or more) hydrogen atom is replaced by fluorine, including perfluorinated groups and partially fluorinated groups; for example, "fluorinated alkyl" refers to an alkyl group in which all or part of the hydrogen atoms are replaced by fluorine; specifically, for example, "fluorinated n-propyl" includes n-propyl with 1-7 hydrogen atoms replaced by fluorine, and "fluorinated methoxy" includes methoxy with 1-3 hydrogen atoms replaced by fluorine.

[0016] As one embodiment of the present invention, R1 and R2 are each independently selected from any one or more combinations of halogenated or unsubstituted C1-C5 (e.g., C2, C3, C4, etc.) alkyl, halogenated or unsubstituted C1-C5 (e.g., C2, C3, C4) alkoxy, halogenated or unsubstituted C3-C8 (e.g., C4, C5, C6, C7, etc.) cycloalkyl, halogenated or unsubstituted C2-C8 (e.g., C3, C4, C5, C6, C7, etc.) alkenyl, and halogenated or unsubstituted C2-C8 (e.g., C3, C4, C5, C6, C7, etc.) alkenyloxy.

[0017] In a preferred embodiment of the present invention, R1 and R2 are each independently selected from any one or more combinations of halogenated or unsubstituted C1-C5 alkyl, halogenated or unsubstituted C1-C5 alkoxy, halogenated or unsubstituted C3-C6 cycloalkyl, halogenated or unsubstituted C2-C4 alkenyl, and halogenated or unsubstituted C2-C4 alkenyloxy.

[0018] In a preferred embodiment of the present invention, R1 and R2 are each independently selected from any one or more combinations of C1-C5 alkyl, C1-C5 fluoroalkyl, C1-C5 alkoxy, C1-C5 fluoroalkoxy, C3-C6 cycloalkyl, C3-C6 fluorocycloalkyl, C2-C4 alkenyl, and C2-C4 fluoroalkenyl.

[0019] In this invention, C1-C5 alkyl groups can be methyl, ethyl, n-propyl, n-butyl, or n-pentyl; C1-C5 fluoroalkyl groups can be monofluoro or polyfluoro groups of methyl, ethyl, n-propyl, n-butyl, or n-pentyl, such as trifluoromethyl (-CF3), difluoroethyl (-C2F2H3), perfluoroethyl (-C2F5), perfluoron-propyl (-C3F7), perfluoron-butyl (-C4F9), or perfluoron-pentyl (-C5F7). 11 C1-C5 alkoxy groups can be methoxy, ethoxy, propoxy, butoxy, or pentoxy groups; C1-C5 fluoroalkoxy groups can be monofluoro or polyfluoro groups of methoxy, ethoxy, propoxy, butoxy, or pentoxy, such as trifluoromethoxy (-OCF3); C3-C6 cycloalkyl groups can be cyclopropyl, cyclobutyl, cyclopentyl, or cyclohexyl; C2-C4 alkenyl groups can be vinyl, propenyl, or butenyl groups; C2-C4 fluoroalkenyl groups can be monofluoro or polyfluoro groups of vinyl, propenyl, or butenyl, such as difluorovinyl (CF2=CH-) or perfluorovinyl (CF2=CF-).

[0020] In some embodiments, R1 and R2 are each independently selected from any one or more combinations of methyl, ethyl, n-propyl, n-butyl, n-pentyl, fluoromethyl, fluoroethyl, fluoron-propyl, fluoron-butyl, fluoron-pentyl, methoxy, ethoxy, propoxy (-OCH2CH2CH3), butoxy (-OCH2CH2CH2CH3), pentoxy (-OCH2CH2CH2CH2CH3), fluoromethoxy, fluoroethoxy, fluoropropoxy, fluorobutoxy, fluoropentoxy, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, vinyl, propenyl, butenyl, fluorovinyl, fluoropropenyl, and fluorobutenyl.

[0021] In some embodiments, R1 and R2 are each independently selected from any one or more combinations of C1-C5 alkyl, C1-C5 fluoroalkyl, C1-C5 alkoxy, C1-C5 fluoroalkoxy, C2-C4 alkenyl, and C2-C4 fluoroalkenyl.

[0022] In some embodiments, R1 and R2 are each independently selected from any one or more combinations of C1-C5 alkyl, C1-C5 fluoroalkyl, C1-C5 alkoxy, and C2-C4 alkenyl.

[0023] In some embodiments, R1 is selected from any one of methyl, ethyl, n-propyl, n-butyl, fluoromethyl (e.g., trifluoromethyl), methoxy, ethoxy, propoxy, butoxy, and vinyl.

[0024] In some embodiments, R2 is selected from any one of methyl, ethyl, n-propyl, n-butyl, fluoromethyl (e.g., trifluoromethyl), methoxy, ethoxy, propoxy, butoxy, and vinyl.

[0025] In this invention, ring A and ring B are each independently selected from any one or more combinations of halogenated or unsubstituted C6-C14 (e.g., C6, C10, C14, etc.) arylene, halogenated or unsubstituted C5-C8 (e.g., C5, C6, C7, C8, etc.) cycloalkyl, halogenated or unsubstituted C5-C8 (e.g., C5, C6, C7, C8, etc.) cycloalkenyl, and halogenated or unsubstituted C3-C8 (e.g., C3, C4, C5, C6, C7, C8, etc.) saturated or unsaturated oxygen-containing heterocyclic groups.

[0026] As one embodiment of the present invention, ring A and ring B are each independently selected from any one or more combinations of halogenated or unsubstituted 1,4-phenylene, halogenated or unsubstituted 1,4-cyclohexylene, halogenated or unsubstituted 1,4-cyclohexenylene, halogenated or unsubstituted tetrahydropyranylene, and halogenated or unsubstituted 1,3-dioxane.

[0027] As one embodiment of the present invention, ring A and ring B are each independently selected from any one or more combinations of fluorinated or unsubstituted 1,4-phenylene, fluorinated or unsubstituted 1,4-cyclohexylene, fluorinated or unsubstituted 1,4-cyclohexenylene, fluorinated or unsubstituted tetrahydropyranylene, and fluorinated or unsubstituted 1,3-dioxane.

[0028] As one embodiment of the present invention, ring A and ring B are each independently selected from any one or more combinations of 1,4-phenylene, 1,4-cyclohexylene, 1,4-cyclohexenylene, tetrahydropyranylene, 1,3-dioxane, and 1,4-phenylene containing 1 to 4 (e.g., 1, 2, 3, 4) fluorine substituents.

[0029] In a preferred embodiment of the present invention, ring A and ring B are each independently selected from any of the following groups: , , , , , , or .

[0030] As one embodiment of the present invention, Z1 and Z2 are each independently selected from any one or more combinations of single bonds, double bonds, -O-, C1-C4 alkylene (e.g., C1, C2, C3, C4 alkylene), C1-C4 alkoxide (e.g., C1, C2, C3, C4 alkoxide), -COO-, -OCO-, -O-C1-C4 alkylene-O-, and C2-C4 alkenyl (e.g., C2, C3, C4 alkenyl); optionally, one or more hydrogen atoms in the C1-C4 alkylene, C1-C4 alkoxide, and C2-C4 alkenyl groups are replaced by fluorine atoms.

[0031] As one embodiment of the present invention, Z1 and Z2 are each independently selected from any one of single bonds, double bonds, -O-, -CH2-, -CH2CH2-, -CH2O-, -OCH2-, -OCH2CH2-, -COO-, -OCO-, -O-CH2-O-, -O-CH2CH2-O-, and -CH=CH-; optionally, one or more hydrogen atoms in -CH2-, -CH2CH2-, -CH2O-, -OCH2-, -OCH2CH2-, -O-CH2-O-, -O-CH2CH2-O-, and -CH=CH- are replaced by fluorine atoms.

[0032] As one embodiment of the present invention, Z1 and Z2 are each independently selected from any one or more combinations of single bonds, double bonds, -O-, -CF2O-, -OCF2-, -CH2O-, -OCH2-, -CH2CH2-, -COO-, -OCO-, -CHFO-, -OCHF-, -O-CH2-O-, -OCHFO-, -CF2-, -CHF-, -CH2-, -CHFCH2-, -CH2CHF-, -CHFCHF-, -CF2CH2-, -CH2CF2-, -CF2CHF-, -CHFCF2-, -CF2CF2-, -CH=CH-, -CF=CH-, -CH=CF-, and -CF=CF-.

[0033] As one embodiment of the present invention, Z1 and Z2 are each independently selected from single bonds, -O-, -CF2O-, -OCF2-, -CH2O-, -OCH2-, -CH2CH2-, -COO-, -OCO- or -CF2CF2-.

[0034] In a preferred embodiment of the present invention, Z1 and Z2 are each independently selected from single bonds, -O-, -CF2O-, -CH2O-, -CH2CH2- or -COO-.

[0035] In some embodiments, Z1 and Z2 are each independently a single bond or -O-. In some embodiments, both Z1 and Z2 are single bonds. In some embodiments, Z1 is a single bond and Z2 is -O-. In some embodiments, Z2 is a single bond and Z1 is -O-.

[0036] In some embodiments, Z1 and Z2 are each independently a single bond, -CH2O-, -OCH2-, or -CH2CH2-.

[0037] In some embodiments, Z1 is a single bond and Z2 is -CH2O- or -CH2CH2-.

[0038] In one embodiment of the present invention, m and n are each independently selected from 0 or 1. In some embodiments, both m and n are 0. In some embodiments, both m and n are 1. In some embodiments, one of m and n is 0 and the other is 1.

[0039] In one embodiment of the present invention, at least one of X1 and X2 is O. In some embodiments, both X1 and X2 are O. In some embodiments, one of X1 and X2 is O, and the other is CH2. In some embodiments, one of X1 and X2 is O, and the other is S.

[0040] In some implementations, X1 and X2 are both CH2. In some implementations, X1 and X2 are both S. In some implementations, one of X1 and X2 is S and the other is CH2.

[0041] As one embodiment of the present invention, the liquid crystal compound has any of the following structures: , , ,

[0042] The definitions of each symbol are the same as those in Equation I.

[0043] As one embodiment of the present invention, the liquid crystal compound has any of the following structures: , , ,

[0044] The definitions of each symbol are the same as those in Equation I.

[0045] As one embodiment of the present invention, the liquid crystal compound has any of the following structures: , , , , , ,

[0046] The definitions of each symbol are the same as those in Equation I.

[0047] As one embodiment of the present invention, the liquid crystal compound has a structure as shown in any of Formulas I-1 to I-43:

[0048] ; The definitions of R1, R2, X1, and X2 are the same as those in Equation I.

[0049] As a specific embodiment of the present invention, the liquid crystal compound includes any of the following compounds with the indicated structures:

[0050] In the compounds LC-1 to LC-138 above, the groups -C3H7, -C3F7, -OC3H7, -OC3F7, -C4H9, -C4F9, -OC4H9, -OC4F9, and -C5H are present. 11 -C5F 11 -OC5H 11 -OC5F 11 All of them have a linear chain structure.

[0051] In a second aspect, the present invention provides a liquid crystal material composition comprising the liquid crystal compound described in the first aspect of the present invention.

[0052] The liquid crystal compound of the present invention can be used alone or in combination with other liquid crystal materials. When used in combination with other liquid crystal materials, as one embodiment of the present invention, the liquid crystal compound provided by the present invention has a mass percentage content of 1 to 60% in the liquid crystal material composition (e.g., 2%, 5%, 8%, 10%, 12%, 15%, 18%, 20%, 22%, 25%, 28%, 30%, 32%, 35%, 38%, 40%, 42%, 45%, 48%, 50%, 52%, 55%, 58% or any value between them).

[0053] In a preferred embodiment of the present invention, the liquid crystal compound provided by the present invention has a mass percentage content of 1 to 40% in the liquid crystal material composition.

[0054] In a preferred embodiment of the present invention, the liquid crystal compound provided by the present invention has a mass percentage content of 5-20% in the liquid crystal material composition.

[0055] Thirdly, the present invention provides a liquid crystal display device comprising the liquid crystal compound described in the first aspect of the present invention, or comprising the liquid crystal material composition described in the second aspect of the present invention.

[0056] In this invention, the liquid crystal display device includes, but is not limited to, TN, ADS, VA, PSVA, FFS, or IPS liquid crystal displays.

[0057] Fourthly, the present invention provides the application of the liquid crystal compound described in the first aspect or the liquid crystal material composition described in the second aspect in the field of liquid crystal displays.

[0058] Furthermore, the application includes the use of the liquid crystal compound or the liquid crystal material composition in a liquid crystal display device, preferably as a liquid crystal material in a liquid crystal display device.

[0059] In this invention, the liquid crystal display device includes, but is not limited to, TN, ADS, VA, PSVA, FFS, and IPS liquid crystal displays.

[0060] Compared with the prior art, the liquid crystal compound provided by the present invention has a relatively long rigid host structure, which can maintain a large dielectric anisotropy of the liquid crystal. Detailed Implementation

[0061] The technical solution of the present invention will be described in detail below. The following embodiments are used to illustrate the present invention, but are not intended to limit the scope of the present invention. Unless otherwise specified, the raw materials are all available from publicly available commercial sources.

[0062] In this invention, the way the ring structure is represented by "—" indicates that the connection point is located at any position on the ring structure where bonding can occur.

[0063] In this invention, " "" indicates the linking site of a functional group.

[0064] In this invention, "each independently" means that when there are multiple subjects, they can be the same or different from each other.

[0065] In this invention, the expression “Ca-Cb” represents that the number of carbon atoms in the group is any integer between a and b. Unless otherwise specified, the number of carbon atoms does not include the number of carbon atoms in the substituents. For example, alkyl groups of C1-C12 can be alkyl groups of C1, C2, C3, C4, C5, C6, C7, C8, C9, C10, C11 or C12.

[0066] Unless otherwise specified, all reagents used in this invention are conventional biochemical reagents; all raw materials, instruments, and equipment used can be obtained through commercial purchase or by existing methods; unless otherwise specified, the reagent dosages are those used in conventional experimental operations; unless otherwise specified, all experimental methods are conventional methods.

[0067] It should be noted that the present invention obtains various performance parameters of liquid crystal compounds by linear fitting according to conventional testing methods in the field. The specific meanings of each performance parameter are as follows: Δε represents dielectric anisotropy (25℃, 1000Hz); γ1 represents rotational viscosity (mPa·s, 25℃); and Δn represents optical anisotropy (25℃).

[0068] Synthesis Example 1: Synthesis of Compound LC-1:

[0069] (1-1) Synthesis of intermediate S1-1: Add starting material M1-1 (0.12 mol), starting material M1-2 (0.1 mol), p-toluenesulfonic acid PTSA (10 mmol), and toluene (300 mL) to a dry three-necked reaction flask. Separate the water using a water separator, reflux the reaction for 4 h, add water (200 mL) to wash, separate the liquid, flush the organic phase column, concentrate, and obtain intermediate S1-1 (yield 87%).

[0070] (1-2) Synthesis of intermediate S1-2: Under nitrogen protection, intermediate S1-1 (0.1 mol), starting material M1-3 (0.1 mol), anhydrous potassium carbonate (0.12 mol), tetra(triphenylphosphine)palladium (0.5 mmol), toluene (200 mL), ethanol (50 mL), and deionized water (50 mL) were added to a dry three-necked reaction flask, and the mixture was heated under reflux for 4 h. After the reaction was completed, the mixture was cooled to room temperature, washed with water, separated, extracted with toluene (200 mL), and the organic phases were combined, concentrated under reduced pressure, and purified by column chromatography to obtain intermediate S1-2 (yield 80%).

[0071] (1-3) Synthesis of intermediate S1-3: Under nitrogen protection, intermediate S1-2 (0.1 mol) was dissolved in THF (200 mL), cooled to -78 °C, and n-butyllithium (2.7 M hexane solution, 0.22 mol) was slowly added dropwise. The reaction was carried out at the controlled temperature for 1 h. DMF (0.25 mol) was added dropwise, and the reaction was carried out at the controlled temperature for 1 h. The temperature was raised to -20 °C, and the mixture was extracted with water (150 mL) and ethyl acetate (200 mL). The organic phases were combined, washed with saturated brine, dried over anhydrous magnesium sulfate, concentrated, pulped with petroleum ether, and filtered to obtain intermediate S1-3 (yield 69%).

[0072] (1-4) Synthesis of compound LC-1: Intermediate S1-3 (0.1 mol) and glacial acetic acid (400 mL) were added to a dry three-necked reaction flask. The mixture was heated to reflux, and a solution of 80% hydrazine hydrate (0.3 mol) in glacial acetic acid (75 mL) was slowly added dropwise. After the addition was complete, the mixture was refluxed for 5 h. After the reaction was completed, the mixture was cooled to room temperature, filtered, and recrystallized from toluene and ethanol to give compound LC-1 (yield 25%). The MS (m / z) of compound LC-1 was 444.03.

[0073] Synthesis Example 2: Synthesis of Compound LC-11:

[0074] (2-1) Synthesis of intermediate S2-1: Under nitrogen protection, starting material M2-1 (0.1 mol) was dissolved in THF (300 mL), cooled to -78 °C, and n-butyllithium (2.7 M hexane solution, 0.11 mol) was slowly added dropwise. The reaction was carried out at a controlled temperature for 1 h, followed by the slow addition of starting material M2-2 (0.11 mol). After the addition was complete, the mixture was brought back to room temperature and quenched in 1 N-hydrochloric acid solution (200 mL). The mixture was then extracted with toluene (100 mL), and the organic phases were combined. The mixture was washed with saturated sodium bicarbonate solution, water, and saturated brine, dried over anhydrous magnesium sulfate, filtered, and the solvent was evaporated. The mixture was then purified by silica gel column chromatography to obtain intermediate S2-1 (yield 87%).

[0075] (2-2) Synthesis of intermediate S2-2: To a dry three-necked reaction flask, add intermediate S2-1 (0.1 mol), p-toluenesulfonic acid PTSA (0.01 mol), and toluene (300 mL), and heat under reflux for 3 hours. After the reaction is complete, cool to room temperature, wash with saturated sodium bicarbonate solution, water, and saturated brine, dry with anhydrous magnesium sulfate, filter, and evaporate the solvent to obtain intermediate S2-2 (yield 91%).

[0076] (2-3) Synthesis of intermediate S2-3: Intermediate S2-2 (0.1 mol), palladium on carbon (10%, 0.035 mol), toluene (100 mL), and ethanol (100 mL) were added to a hydrogenation reactor. The mixture was stirred and hydrogen gas was passed through for 8 hours. After monitoring until no raw material remained, the palladium on carbon was filtered off, the solvent was distilled off, and the mixture was recrystallized from a mixed solvent of toluene and ethanol (V:V = 2:1). The resulting product was filtered and dried to obtain intermediate S2-3 (yield 53%).

[0077] (2-4) Synthesis of intermediate S2-4: Under nitrogen protection, intermediate S2-3 (0.1 mol) was dissolved in THF (200 mL), cooled to -78 °C, and 0.11 mol of n-butyllithium (2.7 M hexane solution) was slowly added dropwise, and the reaction was carried out at the controlled temperature for 1 h. Then, 0.15 mol of trimethyl borate was slowly added dropwise. After the addition was complete, the mixture was brought back to room temperature and quenched in 2N-hydrochloric acid solution (200 mL). The mixture was extracted with toluene (100 mL), and the organic phases were combined, washed with saturated sodium bicarbonate solution, water, and saturated brine, dried over anhydrous magnesium sulfate, filtered, and the solvent was evaporated. The mixture was then purified by silica gel column chromatography to obtain intermediate S2-4 (70% yield).

[0078] (2-5) Synthesis of compound LC-11: Following the synthesis method described in steps (1-1) to (1-4) of Example 1 above, by simply replacing raw material M1-2 with raw material M2-3 and replacing raw material M1-3 with intermediate S2-4, compound LC-11 can be obtained. The MS (m / z) value of compound LC-11 is 496.11.

[0079] Synthesis Example 3: Synthesis of Compound LC-46:

[0080] (3-1) Synthesis of intermediate S3-1: Under nitrogen protection, starting material M2-1 (0.1 mol), starting material M3-1 (0.1 mol), anhydrous potassium carbonate (0.12 mol), tetra(triphenylphosphine)palladium (0.5 mmol), toluene (200 mL), ethanol (50 mL), and deionized water (50 mL) were added to a dry three-necked reaction flask, and the mixture was heated under reflux for 4 h. After the reaction was completed, the mixture was cooled to room temperature, washed with water, separated, extracted with toluene (200 mL), and the organic phases were combined, concentrated under reduced pressure, and purified by column chromatography to give intermediate S3-1 (78% yield).

[0081] (3-2) Synthesis of intermediate S3-2: Under nitrogen protection, intermediate S3-1 (0.1 mol) was dissolved in THF (200 mL), cooled to -78 °C, and 0.11 mol of n-butyllithium (2.7 M hexane solution) was slowly added dropwise, and the reaction was carried out at the controlled temperature for 1 h. Then, 0.15 mol of trimethyl borate was slowly added dropwise. After the addition was complete, the mixture was brought back to room temperature and quenched in 2N-hydrochloric acid solution (200 mL). The mixture was extracted with toluene (100 mL), and the organic phases were combined, washed with saturated sodium bicarbonate solution, water, and saturated brine, dried over anhydrous magnesium sulfate, filtered, and the solvent was evaporated. The mixture was then purified by silica gel column chromatography to obtain intermediate S3-2 (yield 69%).

[0082] (3-3) Synthesis of compound LC-46: Following the synthetic method described in steps (1-2) to (1-4) of Example 1 above, by simply replacing intermediate S1-1 with intermediate S2-5 and starting material M1-3 with intermediate S3-2, compound LC-46 can be obtained. The MS (m / z) value of compound LC-46 is 524.37.

[0083] Synthesis Example 4: Synthesis of Compound LC-54:

[0084] Following the synthesis method described in steps (3-1) to (3-3) of Example 3 above, simply replacing raw material M3-1 with raw material M4-1 yields compound LC-54. The MS (m / z) value of compound LC-54 is 528.26.

[0085] Synthesis Example 5: Synthesis of Compound LC-68:

[0086] (5-1) Synthesis of intermediate S5-3: Referring to the synthesis method in steps (1-2) to (1-4) of the above-mentioned synthesis example 1, only by replacing raw material M1-3 with raw material M5-1 and intermediate S1-1 with raw material M5-2, intermediate S5-3 can be obtained.

[0087] (5-2) Synthesis of intermediate S5-4: Under nitrogen protection, diisopropylamine (0.15 mol) was dissolved in THF (300 mL), cooled to 0 °C, and n-butyllithium (0.12 mol) was slowly added dropwise, with the reaction controlled at temperature for 0.5 h. Then, intermediate S5-3 (0.1 mol) in THF (200 mL) solution was slowly added dropwise, with the reaction controlled at temperature for 1.5 h. Then, DMF (0.1 mol) was slowly added dropwise, with the reaction controlled at temperature for 2 h. After the reaction was completed, the mixture was brought back to room temperature, quenched in 1N-hydrochloric acid solution (500 mL), allowed to stand, separated, extracted with ethyl acetate (100 mL), and the organic phases were combined, washed with saturated sodium bicarbonate solution, water, and saturated brine, dried over anhydrous magnesium sulfate, filtered, evaporated to dryness, and purified by silica gel column chromatography to obtain intermediate S5-4 (yield 73%).

[0088] (5-3) Synthesis of intermediate S5-5: Under nitrogen protection, 0.12 mol of chloromethyl ether phosphate was dissolved in 300 mL of THF, cooled to 0 °C, and 0.12 mol of potassium tert-butoxide was slowly added dropwise, and the reaction was carried out at a controlled temperature for 0.5 h. Then, 0.1 mol of intermediate S5-4 in 300 mL of THF was slowly added dropwise, and the reaction was carried out at a controlled temperature for 1.5 h. After the reaction was completed, the mixture was brought back to room temperature, poured into water, allowed to stand, separated, extracted with 100 mL of ethyl acetate, and the organic phases were combined, dried over anhydrous magnesium sulfate, filtered, and the solvent was evaporated. The mixture was recrystallized from 200 mL of ethanol to obtain the alkenyl ether intermediate. The intermediate was dissolved in 200 mL of toluene, added to a three-necked reaction flask, and 0.12 mol of formic acid solution was added. The mixture was heated to reflux and reacted for 3 h. After the reaction was completed, the mixture was cooled to room temperature, allowed to stand, separated, extracted with toluene (100 mL), the organic phases were combined, dried over anhydrous magnesium sulfate, the solvent was evaporated, and the mixture was frozen and crystallized at -20 °C with toluene (50 g) and petroleum ether (20 g). The crystallization was repeated twice to obtain intermediate S5-5 (yield 71%).

[0089] (5-4) Synthesis of intermediate S5-6: Add starting material M5-3 (0.5 mol), magnesium (0.5 mol), and THF (100 mL) to a dry three-necked reaction flask, and heat to reflux for 1 h. Then add dropwise a THF (300 mL) solution of intermediate S5-5 (0.03 mol), and reflux for 1.5 h. After the reaction is complete, cool to room temperature, pour into water, adjust the pH to 5-6, allow to stand, separate the layers, extract with ethyl acetate (100 mL), combine the organic phases, dry to anhydrous magnesium sulfate, evaporate to dryness, and freeze-crystallize with toluene (50 g) and petroleum ether (20 g) at -20 °C. Repeat the crystallization twice to obtain intermediate S5-6 (yield 74%).

[0090] (5-5) Synthesis of compound LC-68: Under nitrogen protection, intermediate S5-6 (0.1 mol), potassium tert-butoxide (0.1 mol), and DMSO (400 mL) were added to a dry three-necked reaction flask, and the mixture was heated to 120 °C and reacted for 1.5 h. After the reaction was completed, the mixture was cooled to room temperature, poured into water, extracted with ethyl acetate (200 mL), dried over anhydrous magnesium sulfate, and the solution was evaporated to dryness. The solution was then crystallized by freezing with toluene (50 g) and petroleum ether (20 g) at -20 °C. The crystallization was repeated twice to give compound LC-68 (77% yield). The MS (m / z) of compound LC-68 was 524.79.

[0091] Synthesis Example 6: Synthesis of Compound LC-85:

[0092] Following the synthesis method described in steps (1-1) to (1-4) of Example 1 above, simply replacing raw material M1-2 with raw material M6-1 and raw material M1-3 with raw material M6-2 yields compound LC-85. The MS (m / z) value of compound LC-85 is 530.42.

[0093] This invention provides exemplary methods for synthesizing the above-mentioned compounds. Other compounds for which no specific synthesis method is provided can also be prepared using similar methods, requiring only the replacement of raw materials. These methods will not be elaborated here. Alternatively, those skilled in the art can prepare these compounds using other methods in the prior art.

[0094] Effect Experiment Example The performance parameters of the liquid crystal compounds obtained in the above synthetic examples 1-6 were compared with those of the existing liquid crystal compound D-1, and the results are shown in Table 1. The structure of compound D-1 is as follows: .

[0095] Table 1 Performance test results of liquid crystal compounds

[0096] As can be clearly seen from Table 1, the liquid crystal compound provided by the present invention has suitable rotational viscosity, high dielectric anisotropy and optical anisotropy, which are exactly the characteristics needed to improve liquid crystal materials. When used in combination with other liquid crystal materials, it can effectively improve the dielectric anisotropy of the liquid crystal composition, reduce the driving voltage, and obtain a liquid crystal composition with faster response speed.

[0097] Although the present invention has been described in detail above with general descriptions and specific embodiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A liquid crystal compound having the structure shown in Formula I: ; in, X1 and X2 are each independently selected from CH2, O or S; R1 and R2 are each independently selected from any one or more combinations of halogenated or unsubstituted C1-C12 alkyl, halogenated or unsubstituted C1-C12 alkoxy, halogenated or unsubstituted C3-C10 cycloalkyl, halogenated or unsubstituted C2-C12 alkenyl, and halogenated or unsubstituted C2-C12 alkenyloxy. Ring A and ring B are each independently selected from any one or more combinations of halogenated or unsubstituted C6-C14 arylene, halogenated or unsubstituted C5-C8 cycloalkyl, halogenated or unsubstituted C5-C8 cycloalkenyl, and halogenated or unsubstituted C3-C8 saturated or unsaturated oxy-containing heterocyclic groups. Z1 and Z2 are each independently selected from any one or more combinations of single bonds, double bonds, -O-, C1-C4 alkylene, C1-C4 alkoxy, -COO-, -OCO-, -O-C1-C4 alkylene-O-, and C2-C4 alkenyl; optionally, one or more hydrogen atoms in the C1-C4 alkylene, C1-C4 alkoxy, and C2-C4 alkenyl groups are substituted with halogen atoms; m and n are each independently selected from 0, 1, or 2.

2. The liquid crystal compound according to claim 1, characterized in that, R1 and R2 are each independently selected from any one or more combinations of halogenated or unsubstituted C1-C5 alkyl, halogenated or unsubstituted C1-C5 alkoxy, halogenated or unsubstituted C3-C8 cycloalkyl, halogenated or unsubstituted C2-C8 alkenyl, and halogenated or unsubstituted C2-C8 alkenyloxy. Preferably, R1 and R2 are each independently selected from any one or more combinations of C1-C5 alkyl, C1-C5 fluoroalkyl, C1-C5 alkoxy, C1-C5 fluoroalkoxy, C3-C6 cycloalkyl, C3-C6 fluorocycloalkyl, C2-C4 alkenyl, and C2-C4 fluoroalkenyl. Preferably, R1 and R2 are each independently selected from any one or more combinations of methyl, ethyl, n-propyl, n-butyl, n-pentyl, fluoromethyl, fluoroethyl, fluoron-propyl, fluoron-butyl, fluoron-pentyl, methoxy, ethoxy, propoxy, butoxy, pentoxy, fluoromethoxy, fluoroethoxy, fluoropropoxy, fluorobutoxy, fluoropentoxy, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, vinyl, propenyl, butenyl, fluorovinyl, fluoropropenyl, and fluorobutenyl. Preferably, R1 and R2 are each independently selected from any one or more combinations of methyl, ethyl, n-propyl, n-butyl, fluoromethyl, methoxy, ethoxy, propoxy, butoxy, and vinyl.

3. The liquid crystal compound according to claim 1 or 2, characterized in that, Ring A and ring B are each independently selected from any one or more combinations of halogenated or unsubstituted 1,4-phenylene, halogenated or unsubstituted 1,4-cyclohexylene, halogenated or unsubstituted 1,4-cyclohexenylene, halogenated or unsubstituted tetrahydropyranylene, and halogenated or unsubstituted 1,3-dioxane. Preferably, ring A and ring B are each independently selected from any one or more combinations of 1,4-phenylene, 1,4-cyclohexylene, 1,4-cyclohexenylene, tetrahydropyranylene, 1,3-dioxane, and 1,4-phenylene containing 1-4 fluorine substituents; Preferably, ring A and ring B are each independently selected from any of the following groups: , , , , , , or .

4. The liquid crystal compound according to any one of claims 1-3, characterized in that, Z1 and Z2 are each independently selected from any one of single bonds, double bonds, -O-, -CH2-, -CH2CH2-, -CH2O-, -OCH2-, -OCH2CH2-, -COO-, -OCO-, -O-CH2-O-, -O-CH2CH2-O-, and -CH=CH-; optionally, one or more hydrogen atoms in -CH2-, -CH2CH2-, -CH2O-, -OCH2-, -OCH2CH2-, -O-CH2-O-, -O-CH2CH2-O-, and -CH=CH- are replaced by fluorine atoms; Preferably, Z1 and Z2 are each independently selected from any one or more combinations of single bonds, double bonds, -O-, -CF2O-, -OCF2-, -CH2O-, -OCH2-, -CH2CH2-, -COO-, -OCO-, -CHFO-, -OCHF-, -O-CH2-O-, -OCHFO-, -CF2-, -CHF-, -CH2-, -CHFCH2-, -CH2CHF-, -CHFCHF-, -CF2CH2-, -CH2CF2-, -CF2CHF-, -CHFCF2-, -CF2CF2-, -CH=CH-, -CF=CH-, -CH=CF-, and -CF=CF-. Preferably, Z1 and Z2 are each independently selected from single bonds, -O-, -CF2O-, -OCF2-, -CH2O-, -OCH2-, -CH2CH2-, -COO-, -OCO-, or -CF2CF2-.

5. The liquid crystal compound according to any one of claims 1-4, characterized in that, The liquid crystal compound has any of the following structures: ， ， ， The definitions of R1, R2, Z1, Z2, ring A, ring B, X1, X2, m, and n are the same as those in equation I.

6. The liquid crystal compound according to any one of claims 1-5, characterized in that, The liquid crystal compound has a structure as shown in any of Formulas I-1 to I-43: 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 ； The definitions of R1, R2, X1, and X2 are the same as those in Equation I.

7. The liquid crystal compound according to any one of claims 1-6, characterized in that, The liquid crystal compound includes any of the compounds shown in the following structures: ， ， ， ， ， ， ， ， ， ， ， ， ， ， ， ， ， ， ， 。 8. A liquid crystal material composition comprising the liquid crystal compound according to any one of claims 1-7; Preferably, the liquid crystal compound has a mass percentage content of 1-60% in the liquid crystal material composition, more preferably 1-40%, and even more preferably 5-20%.

9. A liquid crystal display device comprising a liquid crystal compound according to any one of claims 1-7, or comprising a liquid crystal material composition according to claim 8; Preferably, the liquid crystal display device includes TN, ADS, VA, PSVA, FFS, and IPS liquid crystal displays.

10. The use of the liquid crystal compound as described in any one of claims 1-7 or the liquid crystal material composition as described in claim 8 in the field of liquid crystal displays; Preferably, the application includes the use of the liquid crystal compound or the liquid crystal material composition in a liquid crystal display device; Preferably, the liquid crystal compound or the liquid crystal material composition is used as a liquid crystal material in the liquid crystal display device; Preferably, the liquid crystal display device includes TN, ADS, VA, PSVA, FFS, and IPS liquid crystal displays.

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