Liquid crystal compound, liquid crystal composition, and high-frequency component

Abstract

This application provides a liquid crystal compound, a liquid crystal composition, and a high-frequency component. The liquid crystal compound of this application has the structure shown in Formula I; wherein R is selected from unsubstituted or R-substituted components. a Replacement of C1~C 10 Alkyl, C1~C 10 Alkoxy, unsubstituted or R a Replace C2~C 10 alkenyl, C2~C 10 Alkenyl group, C3~C 10 cycloalkyl; R a Each is independently selected from halogens or C3~C. 10 Cycloalkyl; ring A is selected from unsubstituted or R b Replacement of C6~C 12 arylene, C3-C6 cycloalkylene, C3-C6 cycloalkenylene; R b Each is independently selected from halogens or C1-C4 alkyl groups; ring B and ring C are each independently selected from or; X1-X 10 Each is independently selected from hydrogen or halogen, and at least two of them simultaneously represent halogen; Z1 and Z2 are each independently selected from chemical bonds; n is 0, 1, or 2.

Description

Technical Field

[0001] This application relates to the field of liquid crystal materials technology, and in particular to a liquid crystal compound, a liquid crystal composition, and a high-frequency component. Background Technology

[0002] Liquid crystal materials have been widely used in optoelectronic display devices, such as various LCD TVs, desktop LCD monitors, and mobile display terminals. Utilizing the characteristic that the effective dielectric constant of liquid crystal materials changes under the influence of an applied electric or magnetic field, novel high-frequency components based on liquid crystal materials have been developed, such as filters, microwave phase shifters, microwave phased array antennas, and metasurfaces.

[0003] The dielectric loss of liquid crystal materials is one of the key parameters determining their insertion loss and energy efficiency in microwave and radio frequency devices. To achieve high-performance liquid crystal microwave devices, liquid crystal materials not only need high dielectric constants and dielectric tunability, but also must effectively reduce dielectric loss. For anisotropic liquid crystal systems, their dielectric loss exhibits significant orientation dependence, meaning that the loss tangent values ​​corresponding to the long axis and short axis of the liquid crystal molecules differ. In practical applications, the maximum value of the loss tangent under different orientations is typically used. In high-frequency device applications, a higher quality factor leads to better device performance. This places more stringent comprehensive performance requirements on liquid crystal materials, namely, simultaneously possessing high dielectric constants, high dielectric tunability, and low dielectric loss tangents. However, existing high-dielectric or highly tunable liquid crystal materials often exhibit significant dielectric losses in the microwave band, leading to a significant increase in device insertion loss and a decrease in operating efficiency, severely restricting the engineering application and large-scale development of liquid crystal-based tunable microwave devices. Existing liquid crystals with low dielectric loss often have very high rotational viscosity and rotational viscosity / elastic constant ratios, which cannot meet the requirements for fast response. Furthermore, increased dielectric tunability often leads to increased rotational viscosity, further slowing down the response speed. Meanwhile, to meet practical applications, liquid crystal materials used in high-frequency components also need to have a wide operating temperature range.

[0004] Therefore, there is an urgent need to develop a novel liquid crystal compound and its composition that combines high dielectric strength, high tunability, low dielectric loss, wide nematic phase temperature range, and low viscosity. Summary of the Invention

[0005] The purpose of this application is to provide a liquid crystal compound, a liquid crystal composition, and a high-frequency component that possesses high dielectric anisotropy, high tunability, and low dielectric loss, while also exhibiting a wide nematic phase temperature range and low viscosity. The specific technical solution is as follows:

[0006] The first aspect of this application provides a liquid crystal compound with the structure shown in Formula I:

[0007] Wherein, R is selected from unsubstituted or R-substituted. a Replacement of C1~C 10 Alkyl, C1~C 10 Alkoxy, unsubstituted or R a Replace C2~C 10 alkenyl, C2~C 10 Alkenyl group, C3~C 10 cycloalkyl; the R a Each is independently selected from halogens or C3~C. 10 cycloalkyl;

[0008] Ring A is selected from unsubstituted or R-substituted rings. b Replacement of C6~C 12 arylene, C3-C6 cycloalkylene, C3-C6 cycloolefin; the R b Each is independently selected from halogens or C1~C4 alkyl groups;

[0009] Rings B and C are each selected independently. or ;X1~X 10 Each is independently selected from hydrogen or halogen, and at least two of them simultaneously represent halogen;

[0010] Z1 and Z2 are each independently selected from chemical bonds;

[0011] n is 0, 1, or 2.

[0012] In one embodiment of this application, R is selected from C1-C6 alkyl groups; ring A is selected from phenylene or cyclohexane; ring B and ring C are each independently selected from... or ;X1~X 10 Each is independently selected from hydrogen or halogen, and at least two of them simultaneously represent halogen.

[0013] In one embodiment of this application, the liquid crystal compound is selected from at least one of the following compounds: .

[0014] A second aspect of this application provides a liquid crystal composition comprising the liquid crystal compound described in the first aspect of this application.

[0015] In one embodiment of this application, the mass percentage of the liquid crystal compound is 60% to 95% based on the mass of the liquid crystal composition.

[0016] In one embodiment of this application, the liquid crystal composition comprises 3 to 20 liquid crystal compounds.

[0017] In one embodiment of this application, the liquid crystal composition comprises 5 to 18 liquid crystal compounds.

[0018] In one embodiment of this application, the liquid crystal composition comprises 7 to 15 liquid crystal compounds.

[0019] In one embodiment of this application, the liquid crystal composition comprises the following liquid crystal compounds: ;

[0020] Based on the mass of the liquid crystal composition, the mass percentage of compound 1 is 7%~10%, the mass percentage of compound 2 is 9%~12%, the mass percentage of compound 3 is 15%~19%, the mass percentage of compound 4 is 7%~10%, the mass percentage of compound 5 is 5%~8%, the mass percentage of compound 6 is 5%~8%, the mass percentage of compound 7 is 4%~6%, the mass percentage of compound 8 is 3%~6%, the mass percentage of compound 9 is 11%~15%, and the mass percentage of compound 10 is 4%~6%.

[0021] A second aspect of this application provides a high-frequency component comprising the liquid crystal compound described in the first aspect of this application or the liquid crystal composition described in the second aspect of this application.

[0022] The beneficial effects of this application are:

[0023] This application provides a liquid crystal compound, a liquid crystal composition, and a high-frequency component. The liquid crystal compound of this application has the structure shown in Formula I: wherein R is selected from unsubstituted or R-substituted components. a Replacement of C1~C 10 Alkyl, C1~C 10 Alkoxy, unsubstituted or R a Replace C2~C 10 alkenyl, C2~C 10 Alkenyl group, C3~C10 cycloalkyl; R a Each is independently selected from halogens or C3~C. 10 Cycloalkyl; ring A is selected from unsubstituted or R b Replacement of C6~C 12 Aryl, C3-C6 cycloalkyl, C3-C6 cycloalkenyl; R b Each is independently selected from halogens or C1-C4 alkyl groups; the B ring and the C ring are each independently selected from... or ;X1~X 10 Each element is independently selected from hydrogen or halogen, and at least two of them simultaneously represent halogen; Z1 and Z2 are each independently selected from chemical bonds; n is 0, 1, or 2. The liquid crystal compound and liquid crystal composition containing the present application possess high dielectric anisotropy, high tunability, and low dielectric loss, while also having a wide nematic phase temperature range and low viscosity, making them suitable for applications such as filters, phase shifters, phased array radar, metasurfaces, and 5G / 6G communications.

[0024] Of course, implementing any product or method of this application does not necessarily require achieving all of the advantages described above at the same time. Detailed Implementation

[0025] The technical solutions of this application will be clearly and completely described below with reference to the embodiments of this application. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. All other embodiments obtained by those skilled in the art based on this application are within the scope of protection of this application.

[0026] The first aspect of this application provides a liquid crystal compound with the structure shown in Formula I:

[0027] Wherein, R is selected from unsubstituted or R-substituted. a Replacement of C1~C 10 Alkyl, C1~C 10 Alkoxy, unsubstituted or R a Replace C2~C 10 alkenyl, C2~C 10 Alkenyl group, C3~C 10 cycloalkyl; the R a Each is independently selected from halogens or C3~C. 10 cycloalkyl;

[0028] Ring A is selected from unsubstituted or R-substituted rings. b Replacement of C6~C 12 arylene, C3-C6 cycloalkylene, C3-C6 cycloolefin; the R b Each is independently selected from halogens or C1~C4 alkyl groups;

[0029] Rings B and C are each selected independently. or ;X1~X 10 Each is independently selected from hydrogen or halogen, and at least two of them simultaneously represent halogen;

[0030] Z1 and Z2 are each independently selected from chemical bonds;

[0031] n is 0, 1, or 2.

[0032] In this application, the choice of halogen is not particularly limited, and the halogen can be fluorine (F), chlorine (Cl), bromine (Br), or iodine (I). The choice of chemical bond is not particularly limited, and the chemical bond can be a single bond, a double bond, or a triple bond.

[0033] In one embodiment of this application, R is selected from C1-C6 alkyl groups; ring A is selected from phenylene or cyclohexane; ring B and ring C are each independently selected from... or ;X1~X 10 Each is independently selected from hydrogen or halogen, and at least two of them simultaneously represent halogen.

[0034] In one embodiment of this application, R is selected from C1-C6 alkyl groups; ring A is selected from phenylene or cyclohexane; ring B and ring C are each independently selected from... or ;X1~X 10 Each is independently selected from hydrogen or fluorine, and at least two of them simultaneously represent fluorine.

[0035] In one embodiment of this application, the liquid crystal compound is selected from at least one of the following compounds: .

[0036] This application does not impose any particular limitation on the preparation method of the liquid crystal compound, as long as it can achieve the purpose of this application. For example, when Z2 is -C≡C-, a palladium-catalyzed Sonogashira coupling reaction is used to establish a molecular skeleton by coupling arylaceyne with a brominated or iodoaniline derivative, and then the aniline derivative intermediate is converted into the target isothiocyanate product: .

[0037] When Z2 is -C≡C-, a palladium-catalyzed Sonogashira coupling reaction is used to establish the molecular skeleton by coupling arylaceyne with a brominated or iodoaniline derivative, and then the aniline derivative intermediate is converted into the target isothiocyanate product: .

[0038] A second aspect of this application provides a liquid crystal composition comprising the liquid crystal compound described in the first aspect of this application.

[0039] The liquid crystal composition of this application is composed of various liquid crystal compounds with different structures and properties, including high dielectric constant, low loss, wide temperature range, and low viscosity. Excellent microwave performance of the liquid crystal composition can be achieved by adjusting the component ratio of the liquid crystal compounds.

[0040] In one embodiment of this application, the mass percentage content of the liquid crystal compound is 60% to 95% based on the mass of the liquid crystal composition. For example, the mass percentage content of the liquid crystal compound can be 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, or a range of any two of these values, based on the mass of the liquid crystal composition.

[0041] In one embodiment of this application, the liquid crystal composition comprises 3 to 20 liquid crystal compounds; preferably, the liquid crystal composition comprises 5 to 18 liquid crystal compounds; more preferably, the liquid crystal composition comprises 7 to 15 liquid crystal compounds. For example, the liquid crystal composition may include 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 liquid crystal compounds, or a range consisting of any two of these values.

[0042] This application does not impose any particular limitation on the preparation method of the liquid crystal composition, as long as it achieves the purpose of this application. For example, various liquid crystal compounds are weighed according to a predetermined mass ratio, then heated and homogenized using magnetic stirring or ultrasonic stirring until all components are completely dissolved; the liquid crystal composition is then obtained after filtration. Liquid crystal compositions can also be prepared using other conventional methods, such as using so-called premixes or so-called "multi-bottle" systems, where the components are themselves ready-to-use mixtures.

[0043] In one embodiment of this application, the liquid crystal composition comprises the following liquid crystal compounds: ;

[0044] Based on the mass of the liquid crystal composition, the mass percentage of compound 1 is 7%~10%, the mass percentage of compound 2 is 9%~12%, the mass percentage of compound 3 is 15%~19%, the mass percentage of compound 4 is 7%~10%, the mass percentage of compound 5 is 5%~8%, the mass percentage of compound 6 is 5%~8%, the mass percentage of compound 7 is 4%~6%, the mass percentage of compound 8 is 3%~6%, the mass percentage of compound 9 is 11%~15%, and the mass percentage of compound 10 is 4%~6%.

[0045] For example, based on the mass of the liquid crystal composition, the mass percentage of compound 1 can be 7%, 8%, 9%, 10%, or a range of any two values ​​therein; the mass percentage of compound 2 can be 9%, 10%, 11%, 12%, or a range of any two values ​​therein; the mass percentage of compound 3 can be 15%, 16%, 17%, 18%, 19%, or a range of any two values ​​therein; the mass percentage of compound 4 can be 7%, 8%, 9%, 10%, or a range of any two values ​​therein; and the mass percentage of compound 5 can be 5%, 6%, 7%, 8%, or a range of any two values ​​therein. The mass percentage of compound 6 can be 5%, 6%, 7%, 8%, or any two of these values; the mass percentage of compound 7 can be 4%, 5%, 6%, or any two of these values; the mass percentage of compound 8 can be 3%, 4%, 5%, 6%, or any two of these values; the mass percentage of compound 9 can be 11%, 12%, 13%, 14%, 15%, or any two of these values; and the mass percentage of compound 10 can be 4%, 5%, 6%, or any two of these values.

[0046] In one embodiment of this application, the liquid crystal composition further includes: .

[0047] Based on the mass of the liquid crystal composition, the mass percentage of compound 11 can be 9%, 10%, 11%, or a range of any two of these values. Compound 11 is a high birefringence liquid crystal monomer with a relatively stable chemical structure, and it plays a role in reducing dielectric loss in the liquid crystal composition.

[0048] A second aspect of this application provides a high-frequency component comprising the liquid crystal compound described in the first aspect of this application or the liquid crystal composition described in the second aspect of this application.

[0049] The liquid crystal compounds and compositions thereof of this application not only possess high dielectric anisotropy, high tunability, and low dielectric loss, but also have advantages such as a wide nematic phase temperature range and low viscosity, making them suitable for applications such as filters, phase shifters, phased array radars, metasurfaces, and 5G / 6G communications. For example, the liquid crystal compositions according to the present invention are particularly suitable for fabricating microwave components and can be used in the UHF band (0.3-1 GHz), L band (1-2 GHz), S band (2-4 GHz), C band (4-8 GHz), X band (8-12 GHz), Ku band (12-18 GHz), K band (18-27 GHz), Ka band (27-40 GHz), V band (50-75 GHz), and W band (75-110 GHz). The construction of phase shifters according to this application is known to those skilled in the art. Typically, loaded line phase shifters, inverted microstrip line phase shifters, finline phase shifters, and preferably antipodal finline phase shifters, slotted phase shifters, microstrip line phase shifters, or coplanar waveguide (CPW) phase shifters are used. These components enable reconfigurable antenna arrays.

[0050] There are no particular limitations on the synthesis method of the liquid crystal compound of this application; any method known to those skilled in the art can be used for synthesis. The following example illustrates the synthesis process of the liquid crystal compound of this application. "Room temperature" as used below refers to 20-30°C, and "overnight" refers to 10-16 hours.

[0051] Preparation Example

[0052] Preparation Example 1: Synthesis of Compound 3

[0053] (1) 13.2 g of 5,8-difluoronaphthalene-2-amine, 100 mL of dichloromethane and 8.4 g of sodium bicarbonate were added to a reaction vessel and stirred at room temperature. 25.4 g of iodine was added in portions and stirred overnight. The organic layer was separated and washed with water-soluble sodium bisulfite and then washed with water until neutral. The solvent was removed by concentration and the product was recrystallized with petroleum ether to obtain 19.3 g of 5,8-difluoro-6-iodonaphthalene-2-amine.

[0054] (2) Under nitrogen protection, 13g of 5,8-difluoro-6-iodonaphthalene-2-amine, 100mL of triethylamine, 0.4g of palladium chloride ditriphenylphosphine, 0.3g of cuprous iodide, and 0.4g of triphenylphosphine were added to the reactor. The temperature was raised to 50℃, and 30mL of a triethylamine solution containing 8.6g of 4-pentylphenylacetylene was added dropwise. After the addition was complete, the reaction was kept at the temperature for 4h. The mixture was cooled to room temperature, filtered, and the filtrate was concentrated to dryness. 100mL of toluene was added, the mixture was washed with water, dried, and the toluene was removed under reduced pressure. Petroleum ether was added and the mixture was recrystallized to obtain 12.8g of brown solid.

[0055] (3) Add 12.8 g of brown solid, 100 mL of chloroform and 25 mL of water obtained in the previous step to the reaction vessel, cool down to below 5 °C, slowly add 7.5 g of sulfur phosgene, and after the addition is complete, heat up to reflux for 2 h, cool down to room temperature, separate the liquids, wash the organic layer with sodium bicarbonate aqueous solution, wash with water until neutral, remove the solvent by vacuum distillation, pass the obtained product through a silica gel column, elute with n-heptane, recrystallize the product with n-heptane to obtain 11.4 g of white solid, namely 1,4-difluoro-6-isothiocyano-2-((4-pentylphenyl)ethynyl)naphthalene (compound 3), with a gas chromatographic purity of 99.9%.

[0056] 1 H NMR (500 MHz, CDCl3) δ (ppm): 0.89 (t, 3H, J = 7.0 Hz), 1.28~1.38(m, 4H), 1.58~1.66 (m, 2H), 2.63 (t, 2H, J = 7.5 Hz), 6.95 (dd, 1H, J1 = 10.5Hz, J2 = 8.5 Hz), 7.08 (d, 1H, J = 16 Hz), 7.18~7.24 (m, 2H), 7.31 (d, 2H, J= 8.0 Hz), 7.42 (d, 2H, J = 8.0 Hz), 7.55 (dd, 1H, J1 = 6.0 Hz, J2 = 2.0 Hz),7.68 (d, 1H, J = 16 Hz).

[0057] DSC: C 55.3 N (48.9) I, where C represents the crystalline state, N represents the liquid crystal state, and I represents the isotropic liquid state. The specific values ​​represent the temperature in °C.

[0058] Preparation Example 2: Synthesis of Compound 4

[0059] The 4-pentylphenylacetylene in Preparation Example 1 was replaced with 4-(4-n-pentylcyclohexyl)phenylacetylene, and the other operations were performed using the same synthetic method as in Preparation Example 1, to obtain 1,4-difluoro-6-isothiocyano-2-((4-(4-pentylcyclohexyl)phenyl)acetylenyl)naphthalene (compound 4).

[0060] 1 H NMR (500 MHz, CDCl3) δ (ppm): 0.886 (t, 3H, J = 7.0 Hz), 1.18~1.42(m, 10H), 1.48~1.78 (m, 7H), 2.55~2.68 (m, 1H), 6.92 (dd, 1H, J1 = 10.5 Hz, J2= 8.5 Hz), 7.01 (d, 1H, J = 16.0 Hz), 7.12~7.22 (m, 2H), 7.33 (d, 2H, J = 8.0Hz), 7.56 (dd, 1H, J1 = 6.0 Hz, J2 = 2.0 Hz), 7.69 (d, 1H, J = 16.0 Hz).

[0061] DSC: C 64.6 N 243.8 I, where C represents the crystalline state, N represents the liquid crystal state, and I represents the isotropic liquid state. The specific values ​​represent temperature, in °C.

[0062] Preparation Example 3: Synthesis of Compound 6

[0063] The 4-pentylphenylacetylene in Preparation Example 1 was replaced with 4'-n-pentyl-4-ethynylbiphenyl, and the other operations were performed using the same synthetic method as in Preparation Example 1, to obtain 1,4-difluoro-6-isothiocyano-2-((4'-pentyl-[1,1'-biphenyl]-4-yl)ethynyl)naphthalene (compound 6).

[0064] 1H NMR (500 MHz, CDCl3) δ (ppm): 0.889 (t, 3H, J = 7.0 Hz), 1.27~1.39(m, 4H), 1.58~1.67 (m, 2H), 2.63 (t, 2H, J = 7.5 Hz), 6.93 (dd, 1H, J1 = 10.5Hz, J2 = 8.5 Hz), 7.02 (d, 1H, J = 16.0 Hz), 7.10~7.18 (m, 2H), 7.23~7.30 (m,4H), 7.36 (d, 2H, J = 8.0 Hz), 7.45 (d, 2H, J = 8.0 Hz), 7.57 (dd, 1H, J1 =6.0 Hz, J2 = 2.0 Hz), 7.71 (d, 1H, J = 16.0 Hz)

[0065] DSC: C 67.3 S 178.6 N 229.4 I, where C represents the crystalline state, N represents the liquid crystal state, and I represents the isotropic liquid state. The specific values ​​represent temperature, in °C.

[0066] Preparation Example 4: Synthesis of Compound 11

[0067] (1) 17.4 g of 3'-methyl-[1,1'-biphenyl]-4-amine, 150 mL of dichloromethane, and 9.7 g of sodium bicarbonate were added to a reaction vessel and stirred at room temperature. 26.3 g of iodine was added in portions and stirred overnight. The organic layer was separated, washed with water-soluble sodium bisulfite, and then washed with water until neutral. The solvent was removed by concentration, and the product was recrystallized with petroleum ether to obtain 23.5 g of 4'-iodo-3'-methyl-[1,1'-biphenyl]-4-amine.

[0068] (2) Under nitrogen protection, 23.5 g of 4'-iodo-3'-methyl-[1,1'-biphenyl]-4-amine, 200 mL of triethylamine, 2.2 g of triphenylphosphine palladium chloride, and 1.3 g of cuprous iodide were added to a three-necked flask. The mixture was stirred and heated to above 40 °C. 100 mL of a triethylamine solution containing 18.4 g of 1-ethynyl-2-methyl-4-propylbenzene was slowly added dropwise. After the addition was complete, the temperature was raised to 50-60 °C and the reaction was stirred for 2 h. The mixture was cooled to room temperature, the salt produced in the reaction was removed by filtration, and the triethylamine was removed by vacuum distillation. 200 mL of toluene was added, and the mixture was washed with water until neutral. The solvent was removed by concentration, and the product was recrystallized from petroleum ether to obtain 25.8 g of brown solid.

[0069] (3) Add 25.8 g of the brown solid obtained in the previous step to a three-necked flask, add 200 mL of chloroform and 50 mL of water, cool to below 5 °C, and slowly add 16.5 g of sulfur phosgene. After the addition is complete, heat to reflux for 2 h. Cool to room temperature, separate the layers, wash the organic layer with sodium bicarbonate aqueous solution, and then wash with water until neutral. Remove the solvent by vacuum distillation, pass the obtained product through a silica gel column, and elute with n-heptane. Recrystallize the product with n-heptane to obtain 22.4 g of white solid with a gas chromatographic purity of 99.8%.

[0070] 1 H NMR (500 MHz, CDCl3) δ (ppm): 0.93 (t, 3H, J = 7.5 Hz), 1.58~1.68(m, 2H), 2.36 (s, 3H), 2.64 (t, 2H, J = 7.5 Hz), 2.42 (s, 3H), 7.08 (d, 2H, J= 8.0 Hz), 7.21 (d, 2H, J = 8.0 Hz), 7.34~7.42 (m, 4H), 7.52 (d, 2H, J = 8.5Hz).

[0071] DSC: C 78.6 N 184.2 I, where C represents the crystalline state, N represents the liquid crystal state, and I represents the isotropic liquid state. The specific values ​​represent temperature, in °C.

[0072] Other compounds in this application can be synthesized by selecting suitable starting materials according to the above-described synthetic compound approach, or by selecting any other suitable method and starting materials.

[0073] Example

[0074] The following examples illustrate the implementation of this application in more detail. Various tests and evaluations were conducted according to the methods described below. Furthermore, unless otherwise specified, "parts" and "%" are quality standards.

[0075] Abbreviation Explanation: Parallel dielectric constant (ε) / / ), vertical dielectric constant (ε) ⊥ ), dielectric anisotropy (Δε), dielectric tunability parameter (τ), quality factor (η), parallel dielectric loss tangent (tanδ) / / ), Vertical dielectric loss tangent (tanδ) ⊥ ), Clear highlights (T) NI Low-temperature storage temperature (LTS), birefringence (Δn), rotational viscosity (γ1), and stretch elastic constant (K). 11 ), bending elastic constant (K) 33 ).

[0076] Test methods and equipment:

[0077] (1) Clear the highlights (T) NI ): Polarizing hot stage method: The liquid crystal composition is coated on a glass slide and placed in an orthogonal polarizing microscopic hot stage, with a heating rate of 2℃ / min. The clearing point (unit: ℃) is the temperature at which the liquid crystal composition begins to turn from a bright state to a black state observed in a polarizing microscope.

[0078] (2) Low Temperature Storage (LTS): 1 mL of the liquid crystal composition was placed in a transparent glass bottle and stored in a low-temperature freezer. The temperature was set to -20℃, -30℃, and -40℃, and stored for 10 days respectively. The presence of crystal precipitation or smectic phase was observed under a polarizing microscope. If crystal precipitation was observed, it was in the dark state; if no crystal precipitation was observed, it was still in the liquid crystal state, and the bright state was observed. If no crystal precipitation was observed at -20℃, the LTS ≤ -20℃; if no crystal precipitation was observed at -30℃, the LTS ≤ -30℃; if no crystal precipitation was observed at -40℃, the LTS ≤ -40℃.

[0079] (3) Birefringence (Δn): Using an Abbe refractometer, under constant temperature of 25℃ and light source of 589nm, the refractive indices of ordinary light (no) and extraordinary light (ne) were measured respectively. The birefringence Δn = ne - no.

[0080] (4) Dielectric anisotropy value (Δε, 1kHz): Measured using an LCR meter under constant temperature conditions of 25℃. Δε=ε ∥ -ε ⊥ That is, the dielectric constant along the long axis of the molecule (ε) ∥ ) and the dielectric constant along the short axis of the molecule (ε) ⊥ The difference between ).

[0081] (5) Elastic constant (K) 11 K 33 Under constant temperature conditions of 25℃, K was obtained by fitting the capacitance-voltage (CV) curve of the liquid crystal. 11 (unit: pN) and K 33 (Unit: pN).

[0082] (6) Rotational viscosity (γ1): Under constant temperature of 25℃, the transient current value I of liquid crystal molecules deflected by electric field was measured by applying voltage to the liquid crystal test cell. p The rotational viscosity γ1 was calculated, in mPa·s.

[0083] (7) Dielectric tunable parameters (τ, 19GHz): Liquid crystal is filled into a polytetrafluoroethylene (PTFE) or fused silica capillary, and the liquid crystal-filled capillary is inserted into the middle of the resonant cavity. Then, an input signal source is applied, and the output signal is recorded using a vector network analyzer. The changes in the resonant frequency and Q factor between the liquid crystal-filled capillary and the blank capillary are measured, and the dielectric constant and loss tangent at 19GHz are calculated. The dielectric constant (ε) perpendicular to and parallel to the liquid crystal director. ∥ , ε ⊥ The component is obtained by the orientation of the liquid crystal in the magnetic field, the direction of the magnetic field is set accordingly, and then rotated by 90° accordingly. The tunable parameter τ = (ε ∥ -ε ⊥ ) / ε ∥ .

[0084] Example 1

[0085] Weigh the liquid crystal compound according to the mass ratio in Table 1, then heat it at a rate of 10℃ / min until it reaches above the clearing point of the liquid crystal composition, while simultaneously using magnetic stirring to homogenize and mix until all components are completely dissolved. The mixture is then filtered to obtain the liquid crystal composition. The test data in Table 1 are obtained using the above testing method.

[0086] Table 1

[0087] Example 2

[0088] Except for weighing the liquid crystal compound according to the mass ratio in Table 2, everything else was the same as in Example 1. The test data in Table 2 were obtained using the above test methods.

[0089] Table 2

[0090] As can be seen from Tables 1 and 2, the liquid crystal composition of this application has a dielectric anisotropy value Δε≥19 at a low frequency of 1kHz, a tunable parameter τ≥0.3, and a vertical dielectric loss tanδ. ⊥The viscosity is ≤0.01; the quality factor η≥36; the nematic phase temperature range is -20 to above 100℃ (i.e., no crystallization at low temperatures down to -20℃, and clearing points exceeding 100℃ at high temperatures), while the rotational viscosity γ1 is low. It is evident that the liquid crystal composition of this application possesses both high dielectric anisotropy and high tunability, enabling a large phase modulation at lower driving voltages; the wide nematic phase temperature range (-20℃ to >100℃) ensures its stability in both cold and high temperature environments; low vertical dielectric loss and a high quality factor help reduce insertion loss in high-frequency components; and the low viscosity helps improve the device's response speed. These results demonstrate that the liquid crystal composition of this application possesses high dielectric anisotropy, high tunability, and low dielectric loss, while also exhibiting a wide nematic phase temperature range and low viscosity.

[0091] The above description is only a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A liquid crystal compound having the structure shown in Formula I: ； in, R is selected from unsubstituted or R-selected. a Replacement of C1~C 10 Alkyl, C1~C 10 Alkoxy, unsubstituted or R a Replace C2~C 10 alkenyl, C2~C 10 Alkenyl group, C3~C 10 cycloalkyl; the R a Each is independently selected from halogens or C3~C. 10 cycloalkyl; Ring A is selected from unsubstituted or R-substituted rings. b Replacement of C6~C 12 arylene, C3-C6 cycloalkylene, C3-C6 cycloolefin; the R b Each is independently selected from halogens or C1~C4 alkyl groups; Rings B and C are each selected independently. or ;X1~X 10 Each is independently selected from hydrogen or halogen, and at least two of them simultaneously represent halogen; Z1 and Z2 are each independently selected from chemical bonds; n is 0, 1, or 2.

2. The liquid crystal compound according to claim 1, wherein, R is selected from C1~C6 alkyl; ring A is selected from phenylene or cyclohexene; ring B and ring C are each independently selected from... or ;X1~X 10 Each is independently selected from hydrogen or halogen, and at least two of them simultaneously represent halogen.

3. The liquid crystal compound according to claim 1, wherein, The liquid crystal compound is selected from at least one of the following compounds: 。 4. A liquid crystal composition comprising the liquid crystal compound according to any one of claims 1 to 3.

5. The liquid crystal composition according to claim 4, wherein, Based on the mass of the liquid crystal composition, the mass percentage of the liquid crystal compound is 60% to 95%.

6. The liquid crystal composition according to claim 4, wherein, The liquid crystal composition comprises 3 to 20 liquid crystal compounds.

7. The liquid crystal composition according to claim 6, wherein, The liquid crystal composition comprises 5 to 18 liquid crystal compounds.

8. The liquid crystal composition according to claim 7, wherein, The liquid crystal composition comprises 7 to 15 liquid crystal compounds.

9. The liquid crystal composition according to claim 4, wherein, The liquid crystal composition includes the following liquid crystal compounds: ； Based on the mass of the liquid crystal composition, the mass percentage of compound 1 is 7%~10%, the mass percentage of compound 2 is 9%~12%, the mass percentage of compound 3 is 15%~19%, the mass percentage of compound 4 is 7%~10%, the mass percentage of compound 5 is 5%~8%, the mass percentage of compound 6 is 5%~8%, the mass percentage of compound 7 is 4%~6%, the mass percentage of compound 8 is 3%~6%, the mass percentage of compound 9 is 11%~15%, and the mass percentage of compound 10 is 4%~6%.

10. A high-frequency component comprising a liquid crystal compound according to any one of claims 1 to 3 or a liquid crystal composition according to any one of claims 4 to 9.

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