Liquid crystal compound and application thereof

Abstract

The invention provides a liquid crystal compound and application thereof. The liquid crystal compound has a structure as shown in a formula I. The liquid crystal compound disclosed by the invention has the excellent characteristics of high dielectric anisotropy, good liquid crystal intersolubility, relatively low rotary viscosity and the like, and can be used for improving the performance of a liquid crystal material. Formula I.

Description

Technical Field

[0001] This invention relates to the field of liquid crystal compound technology, specifically to a novel liquid crystal compound, and also to its applications. Background Technology

[0002] Liquid crystal materials, as environmental materials, have significant research value and promising application prospects in fields such as information display materials and organic optoelectronic materials. Currently, TFT-LCD technology is mature, successfully solving technical challenges related to viewing angle, resolution, color saturation, and brightness. Large-size and small-to-medium-size TFT-LCD displays have gradually become the mainstream flat panel displays in their respective fields. However, the demands on display technology continue to increase, such as requiring liquid crystal displays to achieve faster response times and lower driving voltages to reduce power consumption. This necessitates that liquid crystal materials possess low-voltage driving characteristics, fast response times, wider temperature ranges, and good low-temperature stability.

[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] The purpose of this invention is to develop a new dielectric anisotropic liquid crystal compound that possesses excellent properties such as high dielectric anisotropy, good liquid crystal miscibility, and relatively low rotational viscosity, which can be used to improve the performance of liquid crystal materials.

[0005] In a first aspect, the present invention provides a liquid crystal compound having a structure as shown in Formula I: Formula I; Where X is selected from O or S; R is selected from any one 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 alkenoxy. Ring A and ring B are each independently selected from any one 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. m is 0, 1, or 2, n is 0 or 1, and m and n are not both 0.

[0006] 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.

[0007] 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.

[0008] 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.

[0009] 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.

[0010] 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.

[0011] Unless otherwise specified in this invention, alkyl, alkoxy, alkenyl, and alkenyloxy groups are all linear chains.

[0012] 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.

[0013] 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.

[0014] As one embodiment of the present invention, R is selected from any one of halogenated or unsubstituted C1-C5 (e.g., C2, C3, C4, etc.) alkyl, halogenated or unsubstituted C1-C5 (e.g., C2, C3, C4, etc.) 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.

[0015] In a preferred embodiment of the present invention, R is selected from any one 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.

[0016] As a further preferred embodiment of the present invention, R is selected from any one of C1-C5 alkyl, C1-C5 fluoroalkyl, C1-C5 alkoxy, C1-C5 fluoroalkoxy, C3-C6 cycloalkyl, C2-C4 alkenyl, and C2-C4 fluoroalkenyl.

[0017] 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). 11C1-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-).

[0018] As one embodiment of the present invention, ring A and ring B are each independently selected from 1,4-phenylene, 1,4-cyclohexylene, 1,4-cyclohexenylene, tetrahydropyranylene, 1,3-dioxane, or at least one H-substituted fluorine-containing 1,4-phenylene.

[0019] In a preferred embodiment of the present invention, ring A and ring B are each independently selected from any of the following groups: , , , , , , or .

[0020] In this invention Indicates the location where the group is attached.

[0021] In one embodiment of the present invention, m is 0 and n is 1; or m is 1 and n is 0.

[0022] In one embodiment of the present invention, m is 1 and n is 1.

[0023] In one embodiment of the present invention, m is 2 and n is 0.

[0024] As one embodiment of the present invention, the liquid crystal compound has a structure as shown in any of Formulas I-1 to I-44:

[0025] The definitions of R and X are the same as those in Equation I.

[0026] As a specific embodiment of the present invention, the liquid crystal compound includes any of the following compounds with the indicated structures:

[0027] In the compounds LC-1 to LC-144 above, the groups -C3H7, -C3F7, -C4H9, -C4F9, and -C5H are present. 11 -C5F 11 , -OC3H7, -OC3F7, -OC4H9, -OC4F9, -OC5H 11 -OC5F 11 All of them are linear chains.

[0028] 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.

[0029] 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), preferably 1 to 40%, and more preferably 5 to 20%.

[0030] Thirdly, 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.

[0031] Furthermore, the application of the liquid crystal compound described in the first aspect or the liquid crystal material composition described in the second aspect of the present invention in a liquid crystal display device is preferably as a liquid crystal material in a liquid crystal display device.

[0032] Preferably, the liquid crystal display device includes, but is not limited to, TN, ADS, VA, PSVA, FFS, and IPS liquid crystal displays.

[0033] This invention provides a novel liquid crystal compound that exhibits extremely high dielectric anisotropy and low rotational viscosity, thereby effectively reducing the driving voltage and improving the response speed of the liquid crystal display device. It also features moderate optical anisotropy and high charge retention. Detailed Implementation

[0034] 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.

[0035] 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℃).

[0036] Synthesis Example 1: Synthesis of Compound LC-3 (1-1) Synthesis of intermediate S1-1: Under nitrogen protection, raw material M1-1 (0.1 mol) was dissolved in THF (200 mL), stirred and cooled to below -78 °C, and n-butyllithium (2.5 M hexane solution, 42 mL) was slowly added dropwise. After the addition was complete, the reaction was stirred for 1 h, and then elemental iodine (0.11 mol) in THF (40 mL) solution was slowly added dropwise. After the addition was complete, the reaction solution was restored to room temperature and quenched in 2N-hydrochloric acid aqueous solution (200 mL). The mixture was stirred at room temperature for 1 h, and then the stirring was stopped. The mixture was extracted three times with ethyl acetate (90 mL), the organic phases were combined, washed with water until neutral, dried over anhydrous magnesium sulfate, filtered, the solvent was evaporated, crystallized from toluene, and filtered to obtain intermediate S1-1 (yield 80%).

[0037] (1-2) Synthesis of compound LC-3: Under nitrogen protection, intermediate S1-1 (0.1 mol), starting material M1-2 (0.12 mol), potassium carbonate (0.2 mol), tetra(triphenylphosphine)palladium (0.001 mol), tetrabutylammonium bromide (TBAB) (0.015 mol), toluene (150 mL), isopropanol (150 mL), and water (150 mL) were added to a dry three-necked reaction flask. The mixture was heated to reflux with stirring for 5 h. After the reaction was completed, the mixture was cooled to room temperature and extracted three times with toluene (50 mL). The organic phases were combined, washed with water until neutral, dried over anhydrous magnesium sulfate, filtered, and the solvent was evaporated. The mixture was then purified by silica gel column chromatography to give compound LC-3 (77% yield). The MS (m / z) value of compound LC-3 was 456.28.

[0038] Synthesis Example 2: Synthesis of Compound LC-18 Following the synthesis method described in steps (1-2) of Example 1 above, simply replacing raw material M1-2 with raw material M2-1 yields compound LC-18. The MS (m / z) value of compound LC-18 is 452.15.

[0039] Synthesis Example 3: Synthesis of Compound LC-65 Under nitrogen protection, 0.1 mol of starting material M1-1 was dissolved in 200 mL of THF. The mixture was stirred and cooled to below -78 °C. 42 mL of 2.5 M hexane solution was slowly added dropwise. After the addition was complete, the mixture was stirred for 1 h. Then, 50 mL of 5.12 mol of starting material M3-1 in THF was slowly added dropwise. After the addition was complete, the reaction mixture was brought back to room temperature and quenched in 200 mL of 2N-hydrochloric acid aqueous solution. The mixture was extracted three times with 90 mL of toluene. The organic phases were combined and transferred to a dry three-necked flask. 0.001 mol of p-toluenesulfonic acid was added, and the mixture was heated under reflux for 3 h with stirring. After the reaction was complete, the mixture was cooled to room temperature, and the aqueous phase was separated. The mixture was washed with saturated sodium bicarbonate solution, water, and saturated brine. It was dried over anhydrous magnesium sulfate, filtered, and the solvent was evaporated. The mixture was crystallized from anhydrous ethanol and filtered to obtain compound LC-65 (80% yield). The MS (m / z) value of compound LC-65 was 536.02.

[0040] Synthesis Example 4: Synthesis of Compound LC-69 Following the synthesis method in steps (1-2) of Example 1 above, simply replacing raw material M1-2 with raw material M4-1 yields compound LC-69. The MS (m / z) value of compound LC-69 is 534.43.

[0041] Synthesis Example 5: Synthesis of Compound LC-93 Following the synthesis method in steps (1-2) of Example 1 above, simply replacing raw material M1-2 with raw material M5-1 yields compound LC-93. The MS (m / z) value of compound LC-93 is 512.21.

[0042] Synthesis Example 6: Synthesis of Compound LC-106 Following the synthesis method in steps (1-2) of Example 1 above, simply replacing raw material M1-2 with raw material M6-1 yields compound LC-106. The MS (m / z) value of compound LC-106 is 578.34.

[0043] 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.

[0044] Effect Experiment Example The performance parameters of the liquid crystal compounds obtained in Synthesis Examples 1 to 6 above were compared with those of the liquid crystal compounds in the comparative examples listed in Table 1 below, and the results are shown in Table 1.

[0045] Compounds D-1 and D-2: , .

[0046] Table 1 Performance test results of liquid crystal compounds

[0047] As can be clearly seen from Table 1, compared with compounds D-1 and D-2, the liquid crystal compounds provided by the present invention all have higher dielectric anisotropy and moderate rotational viscosity γ1, which are exactly what is needed to improve liquid crystal materials. Therefore, the dielectric anisotropy Δε of the liquid crystal composition can be effectively improved, the driving voltage can be reduced, and a liquid crystal composition with a faster response speed can be obtained.

[0048] 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 a structure as shown in Formula I: Equation I; in, X is selected from O or S; R is selected from any one 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 alkenoxy. Ring A and ring B are each independently selected from any one 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. m is 0, 1, or 2, n is 0 or 1, and m and n are not both 0.

2. The liquid crystal compound according to claim 1, characterized in that, Ring A and ring B are each independently selected from 1,4-phenylene, 1,4-cyclohexylene, 1,4-cyclohexenylene, tetrahydropyranylene, 1,3-dioxane, or at least one H-substituted fluorine-containing 1,4-phenylene.

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 of the following groups: , , , , , , or .

4. The liquid crystal compound according to any one of claims 1-3, characterized in that, The liquid crystal compound has a structure as shown in any of Formulas I-1 to I-44: The definitions of R and X are the same as those in Equation I.

5. The liquid crystal compound according to any one of claims 1-4, characterized in that, The liquid crystal compound includes any of the compounds shown in the following structures: 。 6. A liquid crystal material composition comprising the liquid crystal compound according to any one of claims 1-5.

7. The liquid crystal material composition according to claim 6, characterized in that, The liquid crystal compound has a mass percentage content of 1-60% in the liquid crystal material composition, preferably 1-40%, and more preferably 5-20%.

8. The use of the liquid crystal compound as described in any one of claims 1-5 or the liquid crystal material composition as described in claim 6 or 7 in the field of liquid crystal displays.

9. The use of the liquid crystal compound as described in any one of claims 1-5 or the liquid crystal material composition as described in claim 6 or 7 in a liquid crystal display device, preferably as a liquid crystal material in a liquid crystal display device.

10. The application according to claim 9, characterized in that, The liquid crystal display device is selected from any one of TN, ADS, VA, PSVA, FFS, and IPS liquid crystal displays.

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