Liquid crystal compound, liquid crystal composition and liquid crystal display device

Abstract

The present invention belongs to the field of liquid crystal display technology and discloses a liquid crystal compound: #imgabs0#. This liquid crystal compound has a large negative dielectric anisotropy of greater than -10, low rotational viscosity, large optical anisotropy, a high clearing point, and good low-temperature miscibility. The present invention also discloses a liquid crystal composition, a liquid crystal display element, and a liquid crystal display containing this liquid crystal compound. The liquid crystal composition is particularly suitable for IPS, VA, and FFS liquid crystal compositions used in small and medium-sized displays or TVs.

Description

Technical Field

[0001] The present invention relates to the field of liquid crystal display technology, and more specifically to a liquid crystal compound, a liquid crystal composition, and a liquid crystal display component. Background Art

[0002] After a lengthy period of fundamental research, thin-film transistor liquid crystal displays (TFT-LCDs) have achieved mass production and commercialization. Their advantages, such as lightness, environmental friendliness, and high performance, have made them a mainstream product in LCD applications. TFT-LCDs can be found in everything from small mobile phone screens to large laptop computers, monitors, and even large LCD TVs.

[0003] Early commercial TFT-LCD products basically adopted the TN display mode, whose biggest problem was its narrow viewing angle. As product sizes increased, especially in the TV field, IPS display mode and VA display mode with wide viewing angle characteristics were successively developed and applied. In particular, improvements based on the VA display mode have achieved breakthrough developments in major companies. This is mainly due to the advantages of the VA mode itself, such as wide viewing angle, high contrast, and no need for friction alignment. In addition, the contrast of the VA mode display is less dependent on the optical anisotropy of the liquid crystal (△n), the thickness of the liquid crystal cell (d), and the wavelength of the incident light (λ), which will make the VA mode a very promising display technology.

[0004] When formulating mixed liquid crystals, it is difficult for formulation engineers to coordinate parameters such as rotational viscosity, clearing point, low-temperature stability, display defect control, and optical anisotropy. There is often no mechanism to refer to for optimizing suitable combinations. Moreover, rotational viscosity and parameters such as dielectric anisotropy, clearing point, and optical anisotropy are contradictory parameters. It is difficult to ensure good dielectric anisotropy, clearing point, and optical anisotropy while also having low rotational viscosity.

[0005] Therefore, the present invention provides a liquid crystal compound, a liquid crystal composition and a liquid crystal display device to solve at least one of the above problems. Summary of the Invention

[0006] One object of the present invention is to provide a liquid crystal compound having a large negative dielectric anisotropy, which can reach above -10, low rotational viscosity, large optical anisotropy, high clearing point, and good low-temperature miscibility.

[0007] The second object of the present invention is to provide a liquid crystal composition containing the liquid crystal compound, which has low rotational viscosity, good photoelectric performance, high clearing point, good low-temperature performance, and less display defects.

[0008] A third object of the present invention is to provide a liquid crystal display element or a liquid crystal display comprising the liquid crystal composition.

[0009] In order to achieve the above object, the present invention adopts the following technical solutions:

[0010] The present invention provides a liquid crystal compound, which is shown in Formula I:

[0011]

[0012] in,

[0013] R a represents an alkyl group having 1 to 10 carbon atoms, a fluorine-substituted alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, a fluorine-substituted alkenyl group having 2 to 10 carbon atoms, an alkenyloxy group having 3 to 8 carbon atoms, or a fluorine-substituted alkenyloxy group having 3 to 8 carbon atoms;

[0014] X represents O or S;

[0015] Z represents ethylene, methyleneoxy or propyleneoxy;

[0016] express

[0017] Effects of the Invention

[0018] After fluorine is added to the liquid crystal compound of the present invention at the side position, the strong electron-withdrawing ability of the fluorine atoms increases the electron cloud density in the vertical direction of the liquid crystal molecules, thereby increasing the vertical dielectric constant and thus increasing the negative dielectric constant of the liquid crystal molecules. Moreover, the addition of fluorine atoms improves the solubility of the molecules. The cyclopropyl, cyclobutyl, and cyclopentyl groups have unique configurations, which are different from the chair configuration of the cyclohexyl group, and have better solubility and a larger dielectric constant. The liquid crystal compound of the present invention has a large negative dielectric anisotropy, which can reach above -10, and has a low rotational viscosity, a large optical anisotropy, a high clearing point, and good low-temperature miscibility. The liquid crystal composition containing the liquid crystal compound of the present invention also has a large negative dielectric anisotropy, a low rotational viscosity, a large optical anisotropy, and a high clearing point, and has good low-temperature miscibility, and can be used to develop low-drive, fast-response liquid crystal display elements or liquid crystal displays. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 The MS mass spectrum of the compound represented by formula I-4-1 is shown DETAILED DESCRIPTION

[0020] The present invention provides a liquid crystal compound, which is shown in Formula I:

[0021]

[0022] in,

[0023] R a represents an alkyl group having 1 to 10 carbon atoms, a fluorine-substituted alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, a fluorine-substituted alkenyl group having 2 to 10 carbon atoms, an alkenyloxy group having 3 to 8 carbon atoms, or a fluorine-substituted alkenyloxy group having 3 to 8 carbon atoms;

[0024] X represents O or S;

[0025] Z represents ethylene, methyleneoxy or propyleneoxy;

[0026] express

[0027] The liquid crystal compound of the present invention has a relatively large negative dielectric anisotropy, which can reach above -10, and has low rotational viscosity, a large elastic constant, a high clearing point and good low-temperature mutual solubility.

[0028] by For example, only F substitution at position 1 can achieve the technical effect of the present invention. Substitution of F at positions 2, 3, 4, and 5 is difficult and costly to synthesize, and the performance of the compound is poor.

[0029] The liquid crystal compound of the present invention is preferably selected from the group consisting of compounds represented by the following formulas I-1 to I-10:

[0030]

[0031] in,

[0032] R a1 represents an alkyl group having 1 to 10 carbon atoms, a fluorine-substituted alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a fluorine-substituted alkoxy group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, a fluorine-substituted alkenyl group having 2 to 10 carbon atoms, an alkenyloxy group having 3 to 8 carbon atoms, or a fluorine-substituted alkenyloxy group having 3 to 8 carbon atoms.

[0033] The liquid crystal compound of the present invention is preferably selected from the group consisting of the compounds represented by the aforementioned formulas I-1 to I-10:

[0034]

[0035] The present invention provides a liquid crystal composition. Preferably, the liquid crystal composition comprises one or more liquid crystal compounds described in Formula I.

[0036] The liquid crystal composition of the present invention preferably comprises one or more compounds represented by formula II:

[0037]

[0038] in:

[0039] R1 and R2 each independently represent an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, or an alkenyl group having 2 to 10 carbon atoms;

[0040] Each independently represents a 1,4-phenylene group or a 1,4-cyclohexylene group.

[0041] In the liquid crystal composition of the present invention, preferably, the compound represented by the aforementioned formula II is selected from the group consisting of the compounds represented by the following formulas II-1 to II-16:

[0042]

[0043] The liquid crystal composition of the present invention preferably comprises one or more compounds represented by formula III:

[0044]

[0045] in,

[0046] R3 and R4 each independently represent an alkyl group having 1 to 10 carbon atoms, a fluorine-substituted alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, a fluorine-substituted alkenyl group having 2 to 10 carbon atoms, an alkenyloxy group having 3 to 8 carbon atoms, or an alkenyloxy group having 3 to 8 carbon atoms substituted by fluorine, and any one or more unconnected CH2 groups in the group represented by R3 may each independently be substituted by a cyclopentylene, a cyclobutylene, or a cyclopropylene group;

[0047] Z1 and Z2 each independently represent a single bond, -CH2CH2- or -CH2O-;

[0048] Each independently represents 1,4-phenylene, 1,4-cyclohexylene, fluorinated 1,4-phenylene or 1,4-cyclohexenylene;

[0049] m and n each independently represent 0, 1 or 2.

[0050] In the liquid crystal composition of the present invention, preferably, the compound represented by the aforementioned formula III is selected from the group consisting of the compounds represented by the following formulas III-1 to III-10:

[0051]

[0052] in,

[0053] R3 and R4 each independently represent an alkyl group having 1-10 carbon atoms, a fluorine-substituted alkyl group having 1-10 carbon atoms, an alkoxy group having 1-10 carbon atoms, a fluorine-substituted alkoxy group having 1-10 carbon atoms, an alkenyl group having 2-10 carbon atoms, a fluorine-substituted alkenyl group having 2-10 carbon atoms, an alkenyloxy group having 3-8 carbon atoms or a fluorine-substituted alkenyloxy group having 3-8 carbon atoms, and any one or more unconnected CH2 groups in the group represented by R3 may each independently be substituted by a cyclopentyl group, a cyclobutyl group or a cyclopropyl group.

[0054] The liquid crystal composition of the present invention, preferably, further comprises one or more compounds represented by formula IV,

[0055]

[0056] in,

[0057] R5 and R6 each independently represent an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, or an alkenyl group having 2 to 10 carbon atoms;

[0058] Each independently represents a 1,4-phenylene group, a fluorinated 1,4-phenylene group, a 1,4-cyclohexylene group, or a 1,4-cyclohexenylene group.

[0059] In the liquid crystal composition of the present invention, preferably, the compound represented by the aforementioned formula IV is selected from the group consisting of compounds represented by the following formulas IV-1 to IV-3,

[0060]

[0061] in:

[0062] R5 and R6 each independently represent an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, or an alkenyl group having 2 to 10 carbon atoms.

[0063] The liquid crystal composition of the present invention, preferably, further comprises one or more compounds represented by formula V,

[0064]

[0065] in,

[0066] R7 and R8 each independently represent an alkyl group having 1 to 10 carbon atoms, a fluorine-substituted alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a fluorine-substituted alkoxy group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, a fluorine-substituted alkenyl group having 2 to 10 carbon atoms, an alkenyloxy group having 3 to 8 carbon atoms, or a fluorine-substituted alkenyloxy group having 3 to 8 carbon atoms;

[0067] represents 1,4-phenylene, 1,4-cyclohexylene or 1,4-cyclohexenylene;

[0068] X1, X2 and X3 each independently represent H or F.

[0069] In the liquid crystal composition of the present invention, preferably, the compound represented by the aforementioned formula V is selected from the group consisting of compounds represented by the following formulas V-1 to V-4:

[0070]

[0071]

[0072] in,

[0073] R 71 、R 81 Each independently represents an alkyl group having 1 to 6 carbon atoms.

[0074] The present invention preferably has the above structural formula specifically represented by compounds represented by formula V-1 to V-4, which have a higher clearing point, generally higher than 200° C., and can more significantly improve the clearing point of liquid crystals.

[0075] Preferably, dopants with various functions may be added to the liquid crystal compound; in the liquid crystal composition, the mass percentage of the dopant is preferably between 0.01-1%.

[0076] Preferably, the dopant is mainly an antioxidant, a light stabilizer, etc.

[0077] Preferably, the antioxidant is selected from one or more compounds represented by the following structural formulas:

[0078]

[0079] Here, S represents an integer from 1 to 10.

[0080] Preferably, the light stabilizer is

[0081]

[0082] in,

[0083] S represents an integer from 1 to 10.

[0084] [Liquid crystal display element or liquid crystal display]

[0085] The present invention also provides a liquid crystal display element or a liquid crystal display comprising the liquid crystal composition.

[0086] Preferably, the aforementioned liquid crystal display element may be an active matrix addressing liquid crystal display element or a passive matrix display element; the liquid crystal display device may be an active matrix addressing liquid crystal display or a passive matrix display.

[0087] Preferably, the active matrix addressing liquid crystal display element is a VA-TFT, FFS-TFT or IPS-TFT liquid crystal display element.

[0088] The liquid crystal display element or liquid crystal display of the present invention comprises a liquid crystal composition composed of the liquid crystal compound of the present invention, and can be used to develop low-drive, fast-response liquid crystal display elements or liquid crystal displays, and is particularly suitable for small and medium-sized displays or IPS, VA, and FFS mode liquid crystal displays for TV applications.

[0089] Example

[0090] In order to explain the present invention more clearly, the present invention will be further described below in conjunction with preferred embodiments. It should be understood by those skilled in the art that the following specific description is illustrative rather than restrictive and should not be used to limit the scope of protection of the present invention.

[0091] In the present invention, the preparation methods are conventional methods unless otherwise specified. The raw materials used are all available from public commercial sources unless otherwise specified. Percentages are by mass percentages, temperatures are in degrees Celsius (°C), and the specific meanings of other symbols and test conditions are as follows:

[0092] Cp represents the clearing point of liquid crystal (℃), measured by DSC quantitative method;

[0093] SN represents the melting point of the liquid crystal from the crystalline state to the nematic phase (°C);

[0094] Δn represents optical anisotropy, Δn=n e -n o , where n o is the refractive index of ordinary light, n eThe refractive index of extraordinary light was measured at 25±2°C, 589 nm, and an Abbe refractometer.

[0095] Δε represents dielectric anisotropy, Δε=ε ∥ -ε ⊥ , where ε ∥ is the dielectric constant parallel to the molecular axis, ε ⊥ is the dielectric constant perpendicular to the molecular axis, tested at 25±0.5°C, 20 μm vertical cell, INSTEC: ALCT-IR1.

[0096] γ1 represents the rotational viscosity (mPa·s), the test conditions are 25±0.5℃, 20 μm vertical cell, INSTEC: ALCT-IR1 test;

[0097] K 11 is the splay elastic constant, K 33 is the bending elastic constant, the test conditions are: 25°C, INSTEC:ALCT-IR1, 20 μm vertical cell;

[0098] Low-temperature observation conditions: Pour 1g of liquid crystal into a 5ml clean glass vial, seal it and place it in a -20℃ low-temperature refrigerator. After 720h, observe whether the liquid crystal crystallizes.

[0099] The liquid crystal monomer structure of the embodiment of the present invention is represented by a code, and the code representation method of the liquid crystal ring structure, end group, and connecting group is shown in Table 1 and Table 2 below.

[0100] Table 1 Corresponding codes of ring structure

[0101]

[0102] Table 2 Corresponding codes of terminal groups and linking groups

[0103]

[0104]

[0105] For example:

[0106] Its code is Sc-CpFO-O4;

[0107] Its code is Sb-CpFO-O4

[0108] Its code is Sb-CpFE-O4;

[0109] Its code is Sb-CpO-O4;

[0110] Its code is Sc-CpO-O3;

[0111] Its code is COY-3-O2;

[0112] Its code is PP-5-3;

[0113] Its code is CY-3-O2;

[0114] Its code is CC-Cp-V1;

[0115] Its code is PGP-Cpr1-2.

[0116] Compound Examples

[0117] The liquid crystal compound of the present invention having the structural formula shown in Formula I can be synthesized by the following synthetic route:

[0118] The present invention refers to the synthesis method of the embodiment of US20150299161 to synthesize intermediate A, and refers to the literature Discovery, optimization, and biological characterization of 2,3,6-trisubstituted pyridine-containing M4 positive allosteric modulators, ChemMedChem, 14(9), 943-951; 2019. Intermediates B, C, D, E, and F are synthesized.

[0119] The structures of intermediates A, B, and C are as follows:

[0120] Intermediate A: Intermediate B:

[0121] Intermediate C: Intermediate D:

[0122] Intermediate E: Intermediate F:

[0123] in,

[0124] R a1represents an alkyl group having 1 to 10 carbon atoms, a fluorine-substituted alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, a fluorine-substituted alkenyl group having 2 to 10 carbon atoms, an alkenyloxy group having 3 to 8 carbon atoms, or a fluorine-substituted alkenyloxy group having 3 to 8 carbon atoms;

[0125] G represents -OH or -CHO.

[0126] The present invention is described below using the following specific examples.

[0127] Synthesis Example 1 Preparation of Liquid Crystal Compound I-3-1

[0128] The preparation route is as follows:

[0129]

[0130] Specific operation process of preparation:

[0131] Compound 29.2g (0.1mol) and compound Dissolve 29.9 g (0.11 mol) of methyl paraformaldehyde in 300 ml of DMF, add 15.2 g (0.11 mol) of anhydrous potassium carbonate, heat to 80°C, and react with stirring for 4 hours. Cool the reaction solution to 40-50°C and pour into ice water. Solid precipitates, which is filtered with suction to obtain a yellow solid. The solid is recrystallized from ethanol to obtain 30.4 g of compound I-3-1 as white crystals, with a yield of 78%.

[0132] △n: 0.1582; ​​△ε: -10.3; γ1: 332 mPa.s; no crystals precipitated after being placed at -20℃ for 720 hours.

[0133] Synthesis Example 2 Preparation of Liquid Crystal Compound I-3-2

[0134] The preparation route is as follows:

[0135]

[0136] Specific operation process of preparation:

[0137] Compound 27.8g (0.1mol) and compound Dissolve 29.9 g (0.11 mol) of iodine in 300 ml of DMF, add 15.2 g (0.11 mol) of anhydrous potassium carbonate, heat to 80°C, and react with stirring for 4 hours. Cool the reaction solution to 40-50°C and pour into ice water. Solid precipitates, which is filtered with suction to obtain a yellow solid. The solid is recrystallized from ethanol to obtain 30.1 g of I-3-2 as white crystals, with a yield of 80%.

[0138] △n: 0.1577; △ε: -9.9; γ1: 306 mPa.s; no crystals were precipitated after being placed at -20℃ for 720 hours.

[0139] Synthesis Example 3 Preparation of Liquid Crystal Compound I-4-1

[0140] The preparation route is as follows:

[0141]

[0142] Specific operation process of preparation:

[0143] Compound 30.8 g (0.1 mol) and compound Dissolve 29.9 g (0.11 mol) of methyl paraben in 300 ml of DMF, add 15.2 g (0.11 mol) of anhydrous potassium carbonate, heat to 80°C, and react with stirring for 4 hours. Cool the reaction solution to 40-50°C and pour into ice water. Solid precipitates, which is filtered with suction to obtain a yellow solid. The solid is recrystallized from ethanol to obtain 30.4 g of compound I-4-1 as white crystals, with a yield of 75%.

[0144] △n: 0.1762; △ε: -13.3; γ1: 550 mPa.s; no crystals precipitated after being placed at -20℃ for 720 hours.

[0145] Synthesis Example 4 Preparation of Liquid Crystal Compound I-4-2

[0146] The preparation route is as follows:

[0147]

[0148] Specific operation process of preparation:

[0149] Compound 29.4g (0.1mol) and compound Dissolve 29.9 g (0.11 mol) of iodine in 300 ml of DMF, add 15.2 g (0.11 mol) of anhydrous potassium carbonate, heat to 80°C, and react with stirring for 4 hours. Cool the reaction solution to 40-50°C and pour into ice water. Solid precipitates, which is filtered with suction to obtain a yellow solid. The solid is recrystallized from ethanol to obtain 28.2 g of I-4-2 as white crystals, with a yield of 72%.

[0150] △n: 0.1758; △ε: -13.2; γ1: 543 mPa.s; no crystals precipitated after being placed at -20℃ for 720 hours.

[0151] Synthesis Example 5 Preparation of Liquid Crystal Compound I-8-1

[0152] The preparation route is as follows:

[0153]

[0154] Specific operation process of preparation:

[0155] Compound 30.8 g (0.1 mol) and compound Dissolve 28.4 g (0.11 mol) of iodine in 300 ml of DMF, add 15.2 g (0.11 mol) of anhydrous potassium carbonate, heat to 80°C, and react with stirring for 4 hours. Cool the reaction solution to 40-50°C and pour into ice water. Solid precipitates, which is filtered with suction to obtain a yellow solid. The solid is recrystallized from ethanol to obtain 27.4 g of compound I-8-1 as white crystals, with a yield of 70%.

[0156] △n: 0.1722; △ε: -12.9; γ1: 523 mPa.s; no crystals precipitated after being placed at -20℃ for 720 hours.

[0157] Synthesis Example 6 Preparation of Liquid Crystal Compound Ⅰ-2-1

[0158] The preparation route is as follows:

[0159]

[0160] Specific operation process of preparation:

[0161] Step 1:

[0162] 2.6 g (0.11 mol) of magnesium chips were added to a 1 L three-necked flask, 50 ml of tetrahydrofuran was added, and the mixture was stirred under nitrogen protection. 18g (0.1mol) was dissolved in 100ml THF, and about 30ml of the solution was added to the reaction flask. After the reaction was initiated, the remaining solution was slowly added dropwise. After the addition was complete, the mixture was heated under reflux for 1 hour. 32g (0.1mol) was dissolved in 100ml of tetrahydrofuran and added dropwise to the reaction flask. After addition, the mixture was heated under reflux for 1h. The heat was turned off, the temperature was lowered, and the reaction solution was poured into ice water. The pH was adjusted to 3-4 with 1mol / L dilute hydrochloric acid. The layers were separated and the aqueous phase was extracted with ethyl acetate (100g x 2). The organic phases were combined, washed with water (100g x 2), and dried over 50g of anhydrous sodium sulfate for 2h. The organic phase was concentrated and recrystallized from 80g of petroleum ether to obtain 28g of a white solid (70% yield).

[0163] Step 2:

[0164] Compound 42.2g (0.1mol) of the compound was dissolved in 400ml of dichloromethane under nitrogen protection and the temperature was controlled at -20°C. 23.2g (0.2mol) of triethylsilane was added dropwise. After the addition was complete, 28.4g (0.2mol) of boron trifluoride etherate was added dropwise. After completion, the mixture was stirred at room temperature for 4h. The pH was adjusted to neutral with 1mol / L sodium bicarbonate solution. The organic phase was washed with water (100g x 2) and dried over 50g of anhydrous sodium sulfate for 2h. The organic phase was concentrated and recrystallized from ethanol to obtain 24g of I-2-1 as white crystals, with a yield of 60%.

[0165] △n: 0.1658; △ε: -10.3; γ1: 562 mPa.s; no crystals were precipitated after being placed at -20℃ for 720 hours.

[0166] Composition Examples

[0167] Example 1

[0168] The formula of the liquid crystal composition and the corresponding properties are shown in Table 3 below.

[0169] Table 3 Formulation of the liquid crystal composition of Example 1 and corresponding properties

[0170]

[0171] Comparative Example 1

[0172] The formula of the liquid crystal composition and the corresponding properties are shown in Table 4 below.

[0173] The compounds of formula I Sb-CpFO-O4 and Sb-CpFO-O3 in Example 1 were replaced by existing similar compounds Sb-CpO-O4 and Sb-CpO-O3, respectively, as Comparative Example 1.

[0174] Table 4 Formula and corresponding properties of the liquid crystal composition of Comparative Example 1

[0175]

[0176] Comparative Example 2

[0177] The formulation and corresponding properties of the liquid crystal composition are shown in Table 5. Comparative Example 2 is obtained by replacing the compounds Sb-CpFO-O4 and Sb-CpFO-O3 of Formula I in Example 1 with existing similar compounds Sc-CpO-O4 and Sc-CpO-O3, respectively.

[0178] Table 5 Formula and corresponding properties of the liquid crystal composition of Comparative Example 2

[0179]

[0180]

[0181] Example 2

[0182] The formula of the liquid crystal composition and the corresponding properties are shown in Table 6 below.

[0183] Table 6 Formulation and corresponding properties of the liquid crystal composition of Example 2

[0184]

[0185] Comparative Example 3

[0186] The formulation and corresponding properties of the liquid crystal composition are shown in Table 7. Comparative Example 3 is obtained by replacing the compounds of Formula I Sc-CpFO-O4 and Sc-CpFO-O3 in Example 2 with existing similar compounds Sc-CpO-O4 and Sc-CpO-O2, respectively.

[0187] Table 7 Formulation and corresponding properties of the liquid crystal composition of Comparative Example 3

[0188]

[0189] Comparative Example 4

[0190] The formulation and corresponding properties of the liquid crystal composition are shown in Table 8. Comparative Example 4 is obtained by replacing the compounds of Formula I Sc-CpFO-O4 and Sc-CpFO-O3 in Example 2 with existing similar compounds Sc-2O-O4 and Sc-2O-O2, respectively.

[0191] Table 8 Formula and corresponding properties of the liquid crystal composition of Comparative Example 4

[0192]

[0193]

[0194] Comparative Example 5

[0195] The formula of the liquid crystal composition and the corresponding properties are shown in Table 9 below.

[0196] Table 9 Formulation and corresponding properties of the liquid crystal composition of Comparative Example 5

[0197]

[0198] Example 3

[0199] The formula of the liquid crystal composition and the corresponding properties are shown in Table 10 below.

[0200] Table 10 Formulation and corresponding properties of the liquid crystal composition of Example 3

[0201]

[0202]

[0203] Comparative Example 6

[0204] The formulation and corresponding properties of the liquid crystal composition are shown in Table 11. Comparative Example 6 is obtained by replacing the compounds of Formula I Sc-CpFO-O4 and Sc-CpFO-O3 in Example 3 with existing similar compounds Sc-CprO-O4 and Sc-CprO-O2, respectively.

[0205] Table 11 Formulation and corresponding properties of the liquid crystal composition of Comparative Example 6

[0206]

[0207] Example 4

[0208] The formula of the liquid crystal composition and the corresponding properties are shown in Table 12 below.

[0209] Table 12 Formulation and corresponding properties of the liquid crystal composition of Example 4

[0210]

[0211] Example 5

[0212] The formula of the liquid crystal composition and the corresponding properties are shown in Table 13 below.

[0213] Table 13 Formulation and corresponding properties of the liquid crystal composition of Example 5

[0214]

[0215]

[0216] Example 6

[0217] The formula of the liquid crystal composition and the corresponding properties are shown in Table 14 below.

[0218] Table 14 Formulation and corresponding properties of the liquid crystal composition of Example 6

[0219]

[0220] Example 7

[0221] The formula of the liquid crystal composition and the corresponding properties are shown in Table 15 below.

[0222] Table 15 Formulation and corresponding properties of the liquid crystal composition of Example 7

[0223]

[0224]

[0225] In summary, the liquid crystal compound of the present invention has a large negative dielectric anisotropy, which can reach above -10, and has a low rotational viscosity, a large optical anisotropy, a high clearing point, and good low-temperature miscibility. The liquid crystal composition containing the liquid crystal compound of the present invention also has a large negative dielectric anisotropy, a low rotational viscosity, a large optical anisotropy, a high clearing point, and good low-temperature miscibility, and can be used to develop low-drive, fast-response liquid crystal display elements or liquid crystal displays.

[0226] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not limitations on the implementation methods of the present invention. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made based on the above description. It is impossible to list all the implementation methods here. All obvious changes or modifications derived from the technical solution of the present invention are still within the scope of protection of the present invention.

Claims

1. A liquid crystal compound, characterized in that: The liquid crystal compound is shown in Formula I: in, R a represents an alkyl group having 1 to 10 carbon atoms, a fluorine-substituted alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, a fluorine-substituted alkenyl group having 2 to 10 carbon atoms, an alkenyloxy group having 3 to 8 carbon atoms, or a fluorine-substituted alkenyloxy group having 3 to 8 carbon atoms; X represents O or S; Z represents ethylene, methyleneoxy or propyleneoxy; express 2. The liquid crystal compound according to claim 1, wherein The compound represented by formula I is selected from the group consisting of compounds represented by formulas I-1 to I-4, I-7 to I-10: in, R a1 represents an alkyl group having 1 to 10 carbon atoms, a fluorine-substituted alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a fluorine-substituted alkoxy group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, a fluorine-substituted alkenyl group having 2 to 10 carbon atoms, an alkenyloxy group having 3 to 8 carbon atoms, or a fluorine-substituted alkenyloxy group having 3 to 8 carbon atoms.

3. The compound according to claim 2, characterized in that The compounds represented by formulas I-1 to I-10 are selected from the group consisting of compounds represented by formulas I-1-1 to I-4-2 and I-7-1 to I-10-1:

4. A liquid crystal composition, characterized in that The liquid crystal composition comprises one or more liquid crystal compounds according to any one of claims 1 to 3.

5. The liquid crystal composition according to claim 4, characterized in that The liquid crystal composition comprises one or more compounds represented by formula II: in, R1 and R2 each independently represent an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, or an alkenyl group having 2 to 10 carbon atoms; Each independently represents a 1,4-phenylene group or a 1,4-cyclohexylene group.

6. The liquid crystal composition according to claim 5, wherein The liquid crystal composition comprises one or more compounds represented by formula III: in, R3 and R4 each independently represent an alkyl group having 1 to 10 carbon atoms, a fluorine-substituted alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, a fluorine-substituted alkenyl group having 2 to 10 carbon atoms, an alkenyloxy group having 3 to 8 carbon atoms, or an alkenyloxy group having 3 to 8 carbon atoms substituted by fluorine, and any one or more unconnected CH2 groups in the group represented by R3 may each independently be substituted by a cyclopentylene, a cyclobutylene, or a cyclopropylene group; Z1 and Z2 each independently represent a single bond, -CH2CH2- or -CH2O-; Each independently represents 1,4-phenylene, 1,4-cyclohexylene, fluorinated 1,4-phenylene or 1,4-cyclohexenylene; m and n each independently represent 0, 1 or 2.

7. The liquid crystal composition according to claim 4 or 6, characterized in that The liquid crystal composition further comprises one or more compounds represented by formula IV: in, R5 and R6 each independently represent an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, or an alkenyl group having 2 to 10 carbon atoms; Each independently represents a 1,4-phenylene group, a fluorinated 1,4-phenylene group, a 1,4-cyclohexylene group, or a 1,4-cyclohexenylene group.

8. The liquid crystal composition according to claim 7, wherein The liquid crystal composition further comprises one or more compounds represented by formula V: in, R7 and R8 each independently represent an alkyl group having 1 to 10 carbon atoms, a fluorine-substituted alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a fluorine-substituted alkoxy group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, a fluorine-substituted alkenyl group having 2 to 10 carbon atoms, an alkenyloxy group having 3 to 8 carbon atoms, or a fluorine-substituted alkenyloxy group having 3 to 8 carbon atoms; represents 1,4-phenylene, 1,4-cyclohexylene or 1,4-cyclohexenylene; X1, X2 and X3 each independently represent H or F. 9 . A liquid crystal display element comprising the liquid crystal composition according to claim 4 , wherein the liquid crystal display element is an active matrix display element or a passive matrix display element. 10 . A liquid crystal display comprising the liquid crystal composition according to claim 4 , wherein the liquid crystal display is an active matrix display or a passive matrix display.

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