TWI711690B - Liquid crystal compound with negative dielectric anisotropy and its application - Google Patents

Abstract

The present invention provides a liquid crystal compound of general formula I with negative dielectric anisotropy. The liquid crystal compound has a large absolute value of dielectric anisotropy, high optical anisotropy, high-definition bright spots, low viscosity, fast The liquid crystal compound with response speed, high voltage holding rate, good mutual solubility, good light stability and low temperature stability, and the preparation process of the liquid crystal compound of general formula I of the present invention, raw materials are readily available, and the synthesis route is simple and easy , Suitable for large-scale industrial production, the present invention also provides a liquid crystal composition containing the liquid crystal compound, and the liquid crystal composition has good liquid crystal properties.

Description

Liquid crystal compound with negative dielectric anisotropy and its application

The present invention relates to a liquid crystal compound, especially a liquid crystal compound with negative dielectric anisotropy and its application.

Liquid crystal display elements can be used in various household appliances such as clocks and electronic calculators, measuring equipment, automotive panels, word processors, computers, printers, televisions, and the like. As a night scene display method, among its representative methods, PC (phase change), TN (twist nematic, twisted nematic), STN (super twisted nematic, super twisted nematic), ECB (electrically controlled birefringence, electronically controlled birefringence), OCB (optically compensated bend), IPS (in-plane switching), VA (vertical alignment), CSH (color super homeotropic, color super homeotropic) ) And other modes. According to the driving mode of the element, it is divided into PM (passive matrix, passive matrix) type and AM (active matrix, active matrix) type. PM is divided into static and multiplexed types. AM is divided into TFT (thin film transistor, thin film transistor), MIM (metal insulator metal, metal-insulating layer-metal) and other types. The types of TFTs include amorphous silicon and polycrystal silicon. The latter is divided into high temperature type and low temperature type according to the manufacturing process. According to the type of light source, liquid crystal display elements are classified into a reflective type using natural light, a transmissive type using backlight, and a semi-transmissive type using two light sources: natural light and backlight.

Among these display modes, the IPS mode, ECB mode, VA mode, or CSH mode is different from the commonly used TN mode or STN mode in that the former uses liquid crystal materials with negative dielectric anisotropy. Among these display methods, VA-type displays driven by AM are used in display elements requiring high speed and wide viewing angles. Among them, the most anticipated application is in liquid crystal elements such as televisions.

Regardless of the display mode, the liquid crystal material used requires low driving voltage, high response speed, wide operating temperature range, large absolute value of negative dielectric anisotropy, high phase transition temperature and good mutual solubility . However, the prior art has a highly conjugated molecular structure and tends to have poor compatibility with other liquid crystal materials, making it difficult to use it as a constituent element of a liquid crystal composition having good electrical properties. In addition, a liquid crystal compound used as a constituent element of a liquid crystal composition requiring light stability, such as a liquid crystal display element of a thin film transistor system, requires high stability. On the other hand, a liquid crystal display element containing a liquid crystal composition with a large absolute value of dielectric anisotropy can lower the base voltage value, lower the driving voltage, and further reduce the power consumption.

For a long time, as a component of a liquid crystal composition having negative dielectric anisotropy that can be used in liquid crystal display elements, a large number of liquid crystal compounds in which hydrogen on the benzene ring is substituted have been studied.

Osman, MA published in Molec.crystals liq.Crystals, 82,295. The negative dielectric anisotropic compound of Ref.1 structure:

Due to the two cyano groups on the side of the molecule of compound Ref.1, the molecule has a large negative dielectric anisotropy (the literature value is -20). The document also pointed out the negative mediation of such side dicyano groups Electrically anisotropic compounds have the following disadvantages: 1) high viscosity; 2) poor mutual solubility with liquid crystal monomers; 3) poor light stability. Due to the above shortcomings, the application of such negative compounds is limited.

In liquid crystals, 1989, Vol. 5, No. 1, 159-170, Reiffenrath et al. proposed the fluorine-containing negative compounds of Ref. 2 and Ref. 3 to avoid the disadvantages of dicyano negative compounds:

Although Ref.2 and Ref.3 side fluorine-containing negative compounds avoid the shortcomings of dicyano negative compounds, they lead to too small negative dielectric anisotropy (Ref.2 dielectric anisotropy literature value It is -4.1, and the literature value of Ref.3 dielectric anisotropy is -6.0). Therefore, fluorine-containing compounds with large negative dielectrics still need to be explored.

Researchers have found that the liquid crystal host composition and RM (reactive mesogen) materials disclosed in the prior art still have some defects when used in PSA displays. Therefore, by no means every arbitrary soluble RM material is suitable for PSA displays, and it is often difficult to find more suitable selection criteria than direct PSA tests using pretilt measurement. When it is desired to polymerize by means of UV light without the addition of a photoinitiator (which may be advantageous for some applications), the choice of liquid crystal host composition becomes smaller.

Prior art PSA displays often show the undesirable "image retention" effect, in which the image produced in the display by addressing the selected picture element remains visible, even when the voltage for that picture element has been disconnected Or when other primitives have been addressed.

In PSA displays, image retention effects may be observed. In this type of display In the device, ambient light or the UV component of the light emitted by the backlight causes unreacted RM material to spontaneously polymerize. In an addressed image element, this may change the tilt angle after a few addressing cycles, which will cause a change in transmittance, while in an unaddressed image element, the tilt angle and transmittance remain unaffected.

Therefore, it is hoped that when the PSA display is manufactured, it is hoped that the PSA display will have as little residual image effect as possible to achieve a better display effect.

Therefore, in order to meet the increasingly high application requirements, the memory in this field is constantly improving the liquid crystal compounds with negative dielectric anisotropy.

Object of the invention: The object of the present invention is to provide a liquid crystal compound with negative dielectric anisotropy, which has a large absolute value of dielectric anisotropy, high optical anisotropy, high-definition bright spots, low viscosity, Fast response speed, high voltage retention, good mutual solubility, good light stability and low temperature stability, so that the polymerizable liquid crystal composition containing the liquid crystal compound has a large absolute value of dielectric anisotropy, Low threshold voltage, fast response speed, high contrast, good mutual solubility, good light stability and low temperature stability, and the liquid crystal device containing the polymerizable liquid crystal composition exhibits little or no image Residual effect.

Another object of the present invention is to provide a synthesis method for synthesizing the above-mentioned liquid crystal composition.

Another object of the present invention is to provide a liquid crystal composition including the above-mentioned liquid crystal compound and a display containing the liquid crystal composition.

其中， 所述R₁獨立地表示1-10個碳原子的取代或未被取代的直鏈或支鏈烷基，2-10個碳原子的取代或未被取代的直鏈或支鏈烯基； 所述R₂獨立地表示1-10個碳原子的取代或未被取代的直鏈或支鏈烷基或烷氧基，2-10個碳原子的取代或未被取代的直鏈或支鏈烯基或烯氧基，其中，一個或多個-CH₂-可以被-O-取代，其前提是氧原子不直接相連； 所述環A表示1，4-亞苯基或1，4-亞環己基； 所述m表示1-12的正整數； 所述n表示0或1； 所述p表示0、1或2。 Technical Solution: In order to accomplish the above-mentioned purpose of the invention, the present invention provides a compound with negative dielectric anisotropy, the compound having the structure of general formula I:

Wherein, said R ₁ independently represents a substituted or unsubstituted linear or branched alkyl group of 1-10 carbon atoms, and a substituted or unsubstituted linear or branched alkenyl group of 2-10 carbon atoms ; The R ₂ independently represents a substituted or unsubstituted linear or branched alkyl or alkoxy group with 1-10 carbon atoms, and a substituted or unsubstituted linear or branched with 2-10 carbon atoms Alkenyl or alkenyloxy, wherein one or more -CH ₂ -may be substituted by -O-, provided that the oxygen atom is not directly connected; the ring A represents 1,4-phenylene or 1,4 -Cyclohexylene; said m represents a positive integer of 1-12; said n represents 0 or 1; said p represents 0, 1 or 2.

In some embodiments of the present invention, the R ₁ independently represents a substituted or unsubstituted linear or branched alkyl group of 1-6 carbon atoms, and a substituted or unsubstituted alkyl group of 2-6 carbon atoms Straight or branched alkenyl.

In some embodiments of the present invention, the m represents a positive integer of 1-6.

In some embodiments of the present invention, the m represents a positive integer of 2-6.

In some embodiments of the present invention, the m represents a positive integer of 3-6.

In some embodiments of the present invention, when n is 1, p is 0, R ₂ independently represents a substituted or unsubstituted linear or branched alkyl group of 1-6 carbon atoms, 2-6 carbon atoms Atomic substituted or unsubstituted linear or branched alkenyl, wherein one or more -CH ₂ -may be substituted by -O-, provided that the oxygen atoms are not directly connected.

；以及

其中， 所述R₁和R₂各自獨立地表示1-6個碳原子的取代或未被取代的直鏈或支鏈烷基，2-6個碳原子的取代或未被取代的直鏈或支鏈烯基。 In some embodiments of the present invention, the compound of general formula I is selected from the group consisting of the following compounds of general formula I-1 to I-4:

;as well as

Wherein, the R ₁ and R ₂ each independently represent a substituted or unsubstituted linear or branched alkyl group with 1-6 carbon atoms, and a substituted or unsubstituted linear or branched alkyl group with 2-6 carbon atoms. Branched alkenyl.

；以及

其中， 所述R₁表示1-6個碳原子的取代或未被取代的直鏈或支鏈烷基，2-6個碳原子的取代或未被取代的直鏈或支鏈烯基。 In some embodiments of the present invention, the compound of general formula I-1 is preferably selected from the group consisting of the following compounds:

;as well as

Wherein, the R ₁ represents a substituted or unsubstituted linear or branched alkyl group of 1-6 carbon atoms, and a substituted or unsubstituted linear or branched alkenyl group of 2-6 carbon atoms.

；以及

其中， 所述R₁表示1-6個碳原子的取代或未被取代的直鏈或支鏈烷基，2-6個碳原子的取代或未被取代的直鏈或支鏈烯基。 In some embodiments of the present invention, the compound of formula I-2 is preferably selected from the group consisting of the following compounds:

;as well as

Wherein, the R ₁ represents a substituted or unsubstituted linear or branched alkyl group of 1-6 carbon atoms, and a substituted or unsubstituted linear or branched alkenyl group of 2-6 carbon atoms.

；以及

其中，所述R₁表示1-6個碳原子的取代或未被取代的直鏈或支鏈烷基，2-6個碳原子的取代或未被取代的直鏈或支鏈烯基。 In some embodiments of the present invention, the compound of formula I-3 is preferably selected from the group consisting of:

;as well as

Wherein, said R ₁ represents a substituted or unsubstituted linear or branched alkyl group with 1-6 carbon atoms, and a substituted or unsubstituted linear or branched alkenyl group with 2-6 carbon atoms.

；以及

其中，所述R₁表示1-6個碳原子的取代或未被取代的直鏈或支鏈烷基，2-6個碳原子的取代或未被取代的直鏈或支鏈烯基。 In some embodiments of the present invention, the compound of formula I-4 is preferably selected from the group consisting of:

;as well as

Wherein, said R ₁ represents a substituted or unsubstituted linear or branched alkyl group with 1-6 carbon atoms, and a substituted or unsubstituted linear or branched alkenyl group with 2-6 carbon atoms.

Another aspect of the present invention provides a liquid crystal composition comprising the liquid crystal compound of the general formula I of the present invention.

其中，所述R₃、R₄、R₅和R₆各自獨立的表示-H、-F、1-10個碳原子的取代或 未被取代的直鏈或支鏈烷基或烷氧基，2-10個碳原子的取代或未被取代的直鏈或支鏈烯基或烯氧基，其中，一個或多個-CH₂-可以被-O-取代，其前提是氧原子不直接相連；所述環A、環B和環C各自獨立的表示1，4-環己基、1，4-亞苯基，其中，1，4-亞苯基中一個或多個不相鄰的H可以被F取代，1，4-環己基中一個或多個不相鄰的-CH₂-可以被-O-取代；所述Z₁表示單鍵、-CH₂O-、-OCH₂-、-COO-、-OCO-或-CH=CH-；所述a表示0、1或2，其中，當a表示0時，環A和環B不同時為1，4-環己基。 In some embodiments of the present invention, the liquid crystal composition further comprises one or more compounds of general formula II and/or one or more compounds of general formula III:

Wherein, said R ₃ , R ₄ , R ₅ and R ₆ each independently represent -H, -F, a substituted or unsubstituted linear or branched alkyl or alkoxy group with 1-10 carbon atoms, A substituted or unsubstituted linear or branched alkenyl or alkenyloxy group with 2-10 carbon atoms, wherein one or more -CH ₂ -can be substituted by -O-, provided that the oxygen atoms are not directly connected ; The ring A, ring B and ring C each independently represent 1,4-cyclohexyl, 1,4-phenylene, wherein one or more non-adjacent H in 1,4-phenylene can be Substituted by F, one or more non-adjacent -CH ₂ -in 1,4-cyclohexyl may be substituted by -O-; said Z ₁ represents a single bond, -CH ₂ O-, -OCH ₂ -,- COO-, -OCO- or -CH=CH-; said a represents 0, 1 or 2, wherein when a represents 0, ring A and ring B are not simultaneously 1,4-cyclohexyl.

其中，所述R₇和R₈各自獨立的表示-H、-F、1-10個碳原子的取代或未被取代的直鏈或支鏈烷基或烷氧基，2-10個碳原子的取代或未被取代的直鏈或支鏈烯基或烯氧基，其中，一個或多個-CH₂-可以被-O-取代，其前提是氧原子不直接相連；所述環D和環E各自獨立的表示1，4-環己基、1，4-亞苯基，其中，1，4-亞苯基中一個或多個H可以被F取代，1，4-環己基中一個或多個不相鄰的-CH₂-可以被-O-取代；所述Z₂表示單鍵、-CH₂O-、-OCH₂-、-COO-、-OCO-或-CH=CH-； 所述c表示0或1。 In some embodiments of the present invention, the liquid crystal composition further comprises: one or more compounds of general formula IV

Wherein, the R ₇ and R ₈ each independently represent -H, -F, a substituted or unsubstituted linear or branched alkyl group or alkoxy group with 1-10 carbon atoms, 2-10 carbon atoms The substituted or unsubstituted linear or branched alkenyl or alkenyloxy group, wherein one or more -CH ₂ -may be substituted by -O-, provided that the oxygen atom is not directly connected; the ring D and Ring E each independently represents 1,4-cyclohexyl and 1,4-phenylene, wherein one or more H in 1,4-phenylene may be substituted by F, and one or more of 1,4-cyclohexyl Multiple non-adjacent -CH ₂ -may be substituted by -O-; the Z ₂ represents a single bond, -CH ₂ O-, -OCH ₂ -, -COO-, -OCO- or -CH=CH-; The c represents 0 or 1.

其中，所述R、R₉和R₁₀各自獨立表示-H、碳原子數為1-7的烷基或烷氧基；所述Y₁和Y₂各自獨立表示單鍵、炔鍵、1-4個碳原子的亞烷基、-O-、-COO-、-OCO-、-OCOO-、-CH₂O-或-OCH₂-；所述X₁和X₂各自獨立表示單鍵、-O-、-COO-、-OCO-或-OCOO-、；所述m₁和m₂各自獨立表示1-6的整數；所述d表示0或1。 In some embodiments of the present invention, the liquid crystal composition further comprises: one or more compounds of general formula V

Wherein, the R, R ₉ and R ₁₀ each independently represent -H, an alkyl group or alkoxy group having 1-7 carbon atoms; the Y ₁ and Y ₂ each independently represent a single bond, an acetylene bond, 1- An alkylene group with 4 carbon atoms, -O-, -COO-, -OCO-, -OCOO-, -CH ₂ O- or -OCH ₂ -; each of X ₁ and X ₂ independently represents a single bond,- O-, -COO-, -OCO- or -OCOO-; said m ₁ and m ₂ each independently represent an integer of 1-6; said d represents 0 or 1.

In some embodiments of the present invention, the R independently represents -H, -CH ₃ , -CH ₂ CH ₃ or -CH ₂ CH ₂ CH ₃ .

In some embodiments of the present invention, the R ₉ and R ₁₀ each independently represent -H or -CH ₃ .

In some embodiments of the present invention, the Y ₁ and Y ₂ each independently represent a single bond, -O-, -COO-, -OCO-, -OCOO-, -CH ₂ O- or -OCH ₂ -, preferably It is a single bond, -O-, -COO-, -OCO- or -OCOO-.

In some embodiments of the present invention, each of X ₁ and X ₂ independently represents a single bond, -O-, -COO- or -OCO-.

Another aspect of the present invention provides a display device including the liquid crystal composition of the present invention.

Another aspect of the present invention provides an application of the liquid crystal composition of the present invention in VA, FFS, IPS, and PSVA display modes.

Beneficial effects: Compared with other negative liquid crystal compounds in the prior art, the liquid crystal compound with general formula I provided by the present invention has a large absolute value of dielectric anisotropy, higher optical anisotropy, high-definition bright spots, and low Viscosity, fast response speed, high voltage holding rate, good mutual solubility, good light stability and low temperature stability, the polymerizable liquid crystal composition containing the liquid crystal compound has a large absolute value of dielectric anisotropy , Low threshold voltage, fast response speed, high contrast, good mutual solubility, good light stability and low temperature stability, and the polymerizable liquid crystal composition shows little or no image retention effect ; And the preparation process of the liquid crystal compound of the general formula I of the present invention, raw materials are readily available, the synthetic route is simple and feasible, and is suitable for large-scale industrial production.

The present invention will be described below in conjunction with specific embodiments. It should be noted that the following embodiments are examples of the present invention, which are only used to illustrate the present invention, but not to limit the present invention. Without departing from the spirit or scope of the present invention, other combinations and various improvements within the concept of the present invention can be made.

For ease of expression, in the following examples, the group structure of the liquid crystal compound is represented by the code listed in Table 1:

The abbreviated codes of the test items in the following examples are as follows: Cp: clearing point (nematic-isotropic phase transition temperature, °C)

△n: Refractive index anisotropy (589nm, 20℃)

△ε: Dielectric anisotropy (1KHz, 25℃)

IS: The residual image of the fixed image has reached an unacceptable level. Observe the time point

Among them, the refractive index anisotropy is measured using an Abbe refractometer under a sodium light (589nm) light source at 25°C; the dielectric test box is a TN90 type with a box thickness of 7 μm.

△ε=ε∥-ε⊥, where ε∥ is the permittivity parallel to the molecular axis, ε⊥ is the permittivity perpendicular to the molecular axis, test conditions: 25℃, 1KHz, test box is TN90 type, box 7μm thick.

Afterimage level test: use 16V voltage to continuously drive the display element, at a fixed time point, observe whether the afterimage of the fixed image reaches an unacceptable level; for example, at the observation time point, the afterimage of the fixed image has reached an unacceptable level The degree is recorded as IS<"the observation time point", if at the observation time point, the residual image of the fixed image does not reach an unacceptable level, it is recorded as IS>"the observation time point".

The fixed observation time points are: 24 hours, 168 hours, 240 hours, 500 hours, and 1000 hours.

The liquid crystal compounds represented by the general formula I prepared in the following examples are all tested for optical anisotropy and clearing point and the extrapolation parameters are determined according to the following methods: The commercial liquid crystal number TS023 produced by Jiangsu Hecheng Display Technology Co., Ltd. was selected as the matrix, and the liquid crystal compound represented by the general formula I was dissolved in the matrix liquid crystal (host) at a weight ratio of 10%, and the optical anisotropy of the mixture was tested , Clearing point and dielectric anisotropy, and extrapolate the liquid crystal performance data of the liquid crystal compound shown in general formula I according to the ratio of addition in the matrix according to the linear relationship.

；以及

母體液晶其性能參數測試結果如下： Cp：112△n：0.08△ε：5.0VHR：98.1%。 The host liquid crystal (host) is obtained by mixing the following compounds in a ratio of 20%:40%:40%:

;as well as

The performance parameter test results of the mother liquid crystal are as follows: Cp: 112△n: 0.08△ε: 5.0VHR: 98.1%.

Example 1

The synthetic route of compound I-1-10 is as follows:

1) Synthesis of compound A2

In a 1L three-necked flask, add 28.4g compound A1, 15.8g 2,3-phenylboronic acid, 42.4g anhydrous sodium carbonate, 200ml toluene, 200ml water, 100ml ethanol, and under nitrogen protection, add 0.5g Pd(PPh ₃ ) ₄ and heat Reflux for 6 hours, post-treatment, and purification by column chromatography to obtain white solid A2, 22.4g, GC>97%, yield: 83%.

2) Synthesis of compound A3

In a 500ml three-necked flask, add 13.5g compound A2, 150ml anhydrous tetrahydrofuran, under nitrogen protection, reduce the temperature to -78℃, dropwise add 21ml n-butyllithium (2.4mol/L n-hexane solution), continue stirring at -78℃ 1h, add dropwise a mixture of 12.6g triisobutyl borate and 100ml anhydrous tetrahydrofuran After stirring for 1 hour, the temperature was raised to -40°C naturally, the reaction solution was poured into a mixture of hydrochloric acid and ice to hydrolyze, after extraction and concentration, 10.6g of pale yellow solid A3 was obtained, HPLC>95%, yield: 68 %.

3) Synthesis of compound A4

In a 500ml three-necked flask, add 10.6g compound A3, 100ml dichloromethane, 50ml dioxane, 11.5g 30% hydrogen peroxide, stir for 3h, post-processing, obtain 9.5g reddish solid A4, GC>97%, yield : 98%.

4) Synthesis of compound I-1-10

In a 500ml three-necked flask, add 2.9g A4, 150ml ethanol, 1.2g sodium hydroxide, 1.3g 4-chlorobutyl methyl ether, heat to reflux for 3h, post-processing, and purification by column chromatography to obtain 2.4g white solid I-1-10 , GC>99%, yield: 81%.

According to the above synthesis method, the compounds shown in Table 2 below can be used to transform compound C and compound A to obtain the target compound:

The liquid crystal properties of the above target compounds are as follows:

Characterization data of compound I-1-10: MS: 372 (6%), 258 (47%), 87 (100%).

Characterization data of compound I-1-6: MS: 358 (93%), 258 (89%), 73 (100%).

Characterization data of compound I-1-2-1: MS: 344 (93%), 258 (100%), 59 (70%).

Characterization data of compound I-1-2-2: MS: 358 (94%), 258 (100%), 73 (50%).

A representative compound among the compounds of general formula I-1 is provided in Example 1. According to the data of the liquid crystal compounds I-1-10, I-1-6, I-1-2-1 and I-1-2-2 in Example 1, it can be seen that the formula I-1 The liquid crystal compound has a large absolute value of dielectric anisotropy and high optical anisotropy.

Example 2

The synthetic route of compound I-4-6 is as follows:

1) Synthesis of compound B1

In a 500ml three-necked flask, add 8.1g compound A2, 150ml dichloromethane, under nitrogen protection, reduce the temperature to 0℃, dropwise add a mixture of 15g boron tribromide and 30ml dichloromethane, after the addition is completed, naturally warm to room temperature , Continue to stir for 8h, and post-process to obtain a white solid, compound B1, 5.4g, GC>97%, yield: 74%.

2) Synthesis of compound B2

In a 500ml three-necked flask, add 5.4g compound B2, 150ml ethanol, 2.7g sodium hydroxide, 2.9g 4-chloropropyl methyl ether, heat to reflux for 3h, post-treatment and purification by column chromatography to obtain 5.4g white solid B2. GC>99%, yield: 77%.

3) Synthesis of compound B3

In a 250ml three-necked flask, add 5.4g compound B2, 80ml anhydrous tetrahydrofuran, under nitrogen protection, reduce the temperature to -78℃, drop 7.5ml n-butyllithium (2.4mol/L n-hexane solution), continue at -78℃ Stir for 1h, add dropwise a mixture of 4.7g of triisobutyl borate and 50ml of anhydrous tetrahydrofuran, continue to stir for 1h, naturally heat up to -40°C, pour the reaction liquid into a mixture of hydrochloric acid and ice to hydrolyze, extract and concentrate to obtain 4.3g light yellow solid B3, HPLC>95%, yield: 70%.

4) Synthesis of compound B4

Add 4.3g compound B3, 100ml dichloromethane, 50ml dioxane, 4.1g 30% hydrogen peroxide to a 500ml three-necked flask, stir for 3h, post-processing, obtain 3.9g reddish solid B4, GC>97%, yield : 98%.

5) Synthesis of compound I-4-6

In a 250ml three-necked flask, add 1.1g B4, 80ml ethanol, 0.4g sodium hydroxide, 0.66g 4-chloromethylethylcyclohexane, heat to reflux for 3h, post-treatment, and purify by column chromatography to obtain 1.0g white solid I-4-6, GC>99%, yield: 66%.

According to the above synthesis method, the compounds shown in Table 3 below can be used to transform compound C and compound A to obtain the target compound:

The liquid crystal properties of the above target compounds are as follows:

Characterization data of compound I-4-6: MS: 454 (37%), 330 (42%), 258 (33%), 73 (100%).

Characterization data of compound I-4-7: MS: MS: 468 (33%), 330 (42%), 258 (33%), 73 (100%).

Characterization data of compound I-4-8: MS: 482 (43%), 330 (51%), 258 (34%), 73 (100%).

Example 2 provides information on representative compounds among the compounds of the general formula I-4. The information on the liquid crystal compounds I-4-6, I-4-7 and I-4-8 in Example 2 can be seen The liquid crystal compound of the general formula I-4 has a large absolute value of dielectric anisotropy, high optical anisotropy, and a suitably high clearing point.

Comparative example 1

The liquid crystal composition of Comparative Example 1 was prepared according to the compounds and weight percentages listed in Table 4, which was filled between the two substrates of the liquid crystal display for performance testing. The test data is shown in the following table:

Mix 99.7% of the composition in Table 4 with 0.3% of compound V-1 to form polymerizable liquid crystal composition M1, inject M1 into the test box, and irradiate UV light (UV lamp parameters, 365nm: 60mw/cm2, 313nm : 0.4mw/cm2) 3 minutes, test the afterimage level, the result: IS <168 hours.

Example 3

The liquid crystal composition of Example 3 was prepared according to the compounds and weight percentages listed in Table 5, and the liquid crystal composition was filled between the two substrates of the liquid crystal display for performance testing. The test data is shown in the following table:

Mix 99.7% of the composition of Table 5 with 0.3% of compound V-1 to form a polymerizable liquid crystal composition M2, inject M2 into the test box, irradiate UV light for 3 minutes, and test the residual image level. The result: IS >500 hours.

Example 4

The liquid crystal composition of Example 4 was prepared according to the compounds and weight percentages listed in Table 6, which was filled between the two substrates of the liquid crystal display for performance testing. The test data is shown in the following table:

Mix 99.7% of the composition in Table 6 with 0.3% of compound V-1 to form a polymerizable liquid crystal composition M3, inject M3 into the test box, irradiate UV light for 3 minutes, and test the residual image level. The result: IS >500 hours.

Example 5

Mix 90% of the liquid crystal composition of Table 4 in Comparative Example 1, 9.7% of I-1-10, and 0.3% of V-1 to form a mixture M4, inject M4 into the test box, irradiate UV light for 3 minutes, and test The afterimage level, the result: IS>240 hours.

It can be seen from the data of Example 1 and Example 2 that the compound of the present invention has a relatively large absolute value of dielectric anisotropy, a suitably high clearing point and a suitably high optical anisotropy, and can be applied to liquid crystal compositions. .

It can be seen from the data of Comparative Example 1, Example 3 and Example 4 that the polymerizable liquid crystal composition containing the compound of the general formula I of the present invention does not have the residual image of the fixed image at a fixed time point of 500 h. Acceptable degree, the polymerizable liquid crystal composition that does not contain the compound of the general formula I of the present invention has an unacceptable degree of residual image of a fixed image at a fixed time point of 168h.

It can be seen from the data of Comparative Example 1 and Example 5 that on the basis of the polymerizable liquid crystal composition described in Comparative Example 1, the compound of the general formula I of the present invention is added to form The polymerizable liquid crystal composition of Example 5 makes the residual image of the fixed image not appear to an unacceptable degree by 240 hours. Therefore, the compound of the present invention can effectively improve the residual image of the fixed image, that is, it contains the The polymerized liquid crystal composition exhibited very little image retention effect.

The above are only the preferred embodiments of the present invention, and are not intended to limit the present invention in any form. Although the present invention has been disclosed as above in preferred embodiments, it is not intended to limit the present invention. Anyone familiar with the profession Those skilled in the art, without departing from the scope of the technical solution of the present invention, can use the technical content disclosed above to make slight changes or modifications to equivalent embodiments with equivalent changes, but those who do not depart from the technical solution content of the present invention are based on the technology of the present invention. Essentially, any simple modifications, equivalent changes and modifications made to the above embodiments still fall within the scope of the technical solutions of the present invention.

Industrial applicability

The liquid crystal compound involved in the present invention can be applied to the field of liquid crystal.

Claims (8)

A liquid crystal compound with negative dielectric anisotropy, the compound having the structure of general formula I:

Wherein, the R ₁ independently represents a substituted or unsubstituted linear or branched alkyl group with 1-10 carbon atoms, and a substituted or unsubstituted linear or branched alkenyl group with 2-10 carbon atoms; The R ₂ independently represents a substituted or unsubstituted linear or branched alkyl or alkoxy group of 1-10 carbon atoms, and a substituted or unsubstituted linear or branched alkene of 2-10 carbon atoms Group or alkenyloxy group, wherein one or more -CH ₂ -can be substituted by -O-, provided that the oxygen atom is not directly connected; the ring A represents 1,4-phenylene or 1,4-cyclic ring Hexyl; the m represents a positive integer of 1-12; the n represents 0 or 1; the p represents 0, 1 or 2. The negative dielectric anisotropy liquid crystal compound as described in item 1 of the patent application, wherein the compound of general formula I is selected from the group consisting of the following compounds of general formula I-1 to I-4:

;as well as

Wherein, the R ₁ and R ₂ each independently represent a substituted or unsubstituted linear or branched alkyl group with 1-6 carbon atoms, and a substituted or unsubstituted linear or branched alkyl group with 2-6 carbon atoms. Alkenyl. A liquid crystal composition containing the liquid crystal compound described in item 1 or 2 of the scope of the patent application. The liquid crystal composition according to item 3 of the scope of patent application, wherein the liquid crystal composition further comprises one or more compounds of general formula II and/or one or more compounds of general formula III:

Wherein, the R ₃ , R ₄ , R ₅ and R ₆ each independently represent -H, -F, a substituted or unsubstituted linear or branched alkyl or alkoxy group with 1-10 carbon atoms, 2 -10 carbon atoms substituted or unsubstituted linear or branched alkenyl or alkenyloxy, wherein one or more -CH ₂ -may be substituted by -O-, provided that the oxygen atoms are not directly connected; The ring A, ring B and ring C each independently represent 1,4-cyclohexyl and 1,4-phenylene, wherein one or more non-adjacent H in 1,4-phenylene can be F Substituted, one or more non-adjacent -CH ₂ -in 1,4-cyclohexyl may be substituted by -O-; the Z ₁ represents a single bond, -CH ₂ O-, -OCH ₂ -, -COO-, -OCO- or -CH=CH-; the a represents 0, 1 or 2, wherein, when a represents 0, ring A and ring B are not simultaneously 1,4-cyclohexyl. The liquid crystal composition described in item 3 of the scope of patent application, wherein the liquid crystal composition further comprises:

Wherein, the R ₇ and R ₈ each independently represent -H, -F, a substituted or unsubstituted linear or branched alkyl or alkoxy group with 1-10 carbon atoms, and a group with 2-10 carbon atoms A substituted or unsubstituted linear or branched alkenyl or alkenyloxy group, wherein one or more -CH ₂ -may be substituted by -O-, provided that the oxygen atom is not directly connected; the ring D and the ring E Each independently represents 1,4-cyclohexyl and 1,4-phenylene, wherein one or more H in 1,4-phenylene can be substituted by F, and one or more of 1,4-cyclohexyl Non-adjacent -CH ₂ -can be replaced by -O-; the Z ₂ represents a single bond, -CH ₂ O-, -OCH ₂ -, -COO-, -OCO- or -CH=CH-; the c represents 0 or 1. The liquid crystal composition according to item 3 of the scope of patent application, wherein the liquid crystal composition further comprises: one or more compounds of general formula V

Wherein, the R, R ₉ and R ₁₀ each independently represent -H, an alkyl group or an alkoxy group having 1-7 carbon atoms; the Y ₁ and Y ₂ each independently represent a single bond, an alkyne bond, 1-4 Alkylene of carbon atom, -O-, -COO-, -OCO-, -OCOO-, -CH ₂ O- or -OCH ₂ -; each of X ₁ and X ₂ independently represents a single bond, -O-, -COO-, -OCO- or -OCOO-; the m ₁ and m ₂ each independently represent an integer of 1-6; the d represents 0 or 1. A display device comprising the liquid crystal composition described in item 3 of the scope of the patent application. A display device comprising the liquid crystal composition described in any one of items 4 to 6 in the scope of the patent application.