TWI845872B - A liquid crystal composition and its preparation method and application - Google Patents

Abstract

The present invention belongs to the technical field of liquid crystal compounds, and specifically relates to a liquid crystal composition and its preparation method and application. The liquid crystal composition has a liquid crystal compound having a structure shown in general formula (I). The liquid crystal compound of the present invention has a large optical anisotropy △n and a low rotational viscosity γ1 while maintaining an appropriate negative dielectric anisotropy △ε and an appropriate clearing point Cp, which can improve the mutual solubility of the liquid crystal composition, broaden the liquid crystal phase range of the liquid crystal composition, increase the operating temperature range of the liquid crystal display, and effectively shorten the response time of the liquid crystal display device.

Description

A liquid crystal composition and its preparation method and application

The present invention belongs to the field of liquid crystal compound technology, and specifically relates to a liquid crystal composition and its preparation method and application.

Liquid crystal materials as environmental materials have great research value and bright application prospects in the fields of information display materials, organic optoelectronic materials, etc. Liquid crystal materials as new display materials have many advantages, such as extremely low power consumption and low driving voltage. At the same time, compared with other materials, they also have the advantages of small size, light weight, long life, large amount of displayed information, and no electromagnetic radiation. They can almost meet the requirements of various information displays, especially in TFT-LCD (thin film transistor technology) products.

In the TFT active matrix system, there are mainly TN (Twisted Nematic) mode, IPS (In-Plane Switching) mode, FFS (Fringe Field Switching) mode and VA (Vertical Alignment) mode.

At present, TFT-LCD product technology has matured and successfully solved technical problems such as viewing angle, resolution, color saturation and brightness. Large-size and small- and medium-size TFT-LCD displays have gradually occupied the mainstream position of flat panel displays in their respective fields. For dynamic picture display applications, in order to achieve high-quality display and eliminate display screen afterimages and tailing, the liquid crystal material is required to have a very fast response speed, so the liquid crystal material is required to have the lowest possible rotational viscosity γ1. In addition, in order to reduce the energy consumption of liquid crystal display devices, the driving voltage of the liquid crystal needs to be as low as possible, so it is required to improve the dielectric anisotropy △ε of the liquid crystal.

Liquid crystal materials are the core functional materials of liquid crystal display devices. In order to meet the requirements of various performance parameters of liquid crystal display devices and adapt to the process requirements of liquid crystal display devices, liquid crystal materials need to have a wide range of performance parameters. On the basis of reducing the rotational viscosity γ1 of liquid crystal materials and improving the dielectric anisotropy △ε of liquid crystals, they also need to have appropriate optical anisotropy and a higher cooling point. In order to improve the performance of materials to adapt to new requirements, the synthesis of new structural liquid crystal compounds and the study of structure-performance relationships have become an important task in the field of liquid crystals.

The first object of the present invention is to provide a liquid crystal compound of a novel liquid crystal composition to improve the deficiencies of existing liquid crystal materials and enhance the application value of such liquid crystal compounds. The liquid crystal compound of the present invention has a structure shown in general formula (I):

In the general formula (I), _R1 represents H, an alkenyl group having 2-12 carbon atoms, or an alkenyloxy group having 2-12 carbon atoms; wherein one or more hydrogens in the alkenyl group having 2-12 carbon atoms or the alkenyloxy group having 2-12 carbon atoms may be optionally substituted by a halogen, and one or more _-CH2- groups may be independently substituted by -C≡C-, -CH=CH-, -CF=CF-, -CF=CH-, -COO-, -OCO-, or -O-; Z represents a single bond, -O-, or _-OCH2- ; A represents a single bond, cyclobutyl, cyclopropyl, cyclohexyl,

_R2 represents H, represents an alkyl group having 1 to 12 carbon atoms, an alkenyl group having 2 to 12 carbon atoms or an alkenyloxy group having 2 to 12 carbon atoms.

Preferably, in the general formula (I), _R1 represents an alkenyloxy group having 2-7 carbon atoms; _R2 represents H, represents an alkyl group having 1-7 carbon atoms, an alkenyl group having 2-7 carbon atoms or an alkenyloxy group having 2-7 carbon atoms; further preferably, _R1 represents an alkenyloxy group having 2-7 carbon atoms, and the oxygen in the alkenyloxy group is connected to the carbon atom on the benzene ring in the general formula (I).

為主體結構的基礎上，進一步左側輔以烯氧基端基，右側輔以其他基團，不僅具有適當的負介電各向異性△ε及適當的清亮點Cp，旋轉粘度γ1降低，使得液晶顯示裝置的回應時間有效縮短。 The present invention aims to develop a liquid crystal compound that meets the process requirements of liquid crystal display devices. Through a large number of experiments, it is found that the liquid crystal compound that meets the process requirements of liquid crystal display devices is

On the basis of the main structure, it is further assisted by olefinic oxide end groups on the left side and other groups on the right side. It not only has appropriate negative dielectric anisotropy △ε and appropriate clearing point Cp, but also reduces the rotational viscosity γ1, which effectively shortens the response time of the liquid crystal display device.

Preferably, the liquid crystal compound of the present invention is selected from one or more of the following compounds:

The second object of the present invention is to provide a method for preparing the above-mentioned liquid crystal compound, and the synthesis route thereof is as follows:

與

通過suzuki反應，得到

(2)

通過有機鋰試劑，與溴素反應，得到

(3)

與巰基丙酸乙酯反應，得到

；(4)

經催化合環，得到

；其中，R₁、R_2、Z、A的指代同前面所述。 Specifically, the steps include: (1)

and

Through the Suzuki reaction, we get

(2)

Through the reaction of organic lithium reagent with bromine, we can obtain

(3)

Reaction with ethyl propionate to obtain

; (4)

After catalytic cyclization,

; wherein, R ₁ , R _{2 ,} Z, and A have the same meanings as described above.

The above intermediates can be synthesized through public commercial channels or methods known in the literature.

The third object of the present invention is to provide a liquid crystal composition comprising the liquid crystal compound described in the present invention.

Preferably, the mass percentage of the liquid crystal compound in the liquid crystal composition is 1 to 60%, preferably 3 to 50%, and further preferably 5 to 25%.

The fourth purpose of the present invention is to protect the application of the above-mentioned liquid crystal compound and the composition containing the above-mentioned liquid crystal compound in the field of liquid crystal display, preferably in a liquid crystal display device, and the liquid crystal display device is further preferably a TN, ADS, VA, PSVA, FFS or IPS liquid crystal display.

The present invention has the following beneficial effects: the liquid crystal compound of the present invention has a large optical anisotropy △n, a lower rotational viscosity γ1, and a more excellent solubility while maintaining an appropriate negative dielectric anisotropy △ε and an appropriate clearing point Cp. It can improve the solubility of the liquid crystal composition, broaden the liquid crystal phase range of the liquid crystal composition, increase the operating temperature range of the liquid crystal display, and effectively shorten the response time of the liquid crystal display device.

The liquid crystal compound of the present invention has a structure shown by general formula (I):

In the general formula (I), _R1 represents H, an alkenyl group having 2-12 carbon atoms, or an alkenyloxy group having 2-12 carbon atoms; wherein one or more hydrogens in the alkenyl group having 2-12 carbon atoms or the alkenyloxy group having 2-12 carbon atoms may be optionally substituted by halogens, and one or more _-CH2- groups may be independently substituted by -C≡C-, -CH=CH-, -CF=CF-, -CF=CH-, -COO-, -OCO-, or -O-; Z represents a single bond, -O-, or _-OCH2- ; A represents a single bond, cyclobutyl, cyclopropyl, cyclohexyl,

_R2 represents H, represents an alkyl group having 1 to 12 carbon atoms, an alkenyl group having 2 to 12 carbon atoms or an alkenyloxy group having 2 to 12 carbon atoms.

Preferably, in the general formula (I), _R1 represents an alkenyloxy group having 2-7 carbon atoms; _R2 represents H, represents an alkyl group having 1-7 carbon atoms, an alkenyl group having 2-7 carbon atoms or an alkenyloxy group having 2-7 carbon atoms; further preferably, _R1 represents an alkenyloxy group having 2-7 carbon atoms, and the oxygen in the alkenyloxy group is connected to the carbon atom on the benzene ring in the general formula (I).

為主體結構的基礎上，進一步左側輔以烯氧基端基，右側輔以其他基團，不僅具有適當的負介電各向異性△ε及適當的清亮點Cp，旋轉粘度γ1降低，使得液晶顯示裝置的回應時間有效縮短。 The present invention aims to develop a liquid crystal compound that meets the process requirements of liquid crystal display devices. Through a large number of experiments, it is found that the liquid crystal compound that meets the process requirements of liquid crystal display devices is

On the basis of the main structure, it is further assisted by olefinic oxide end groups on the left side and other groups on the right side. It not only has appropriate negative dielectric anisotropy △ε and appropriate clearing point Cp, but also reduces the rotational viscosity γ1, which effectively shortens the response time of the liquid crystal display device.

Preferably, the liquid crystal compound of the present invention is selected from one or more of the following compounds:

The present invention provides a method for preparing the above-mentioned liquid crystal compound, and its synthesis route is as follows:

與

通過suzuki反應，得到

(2)

通過有機鋰試劑，與溴素反應，得到

(3)

與巰基丙酸乙酯反應，得到

；(4)

經催化合環，得到

；其中，R₁、R_2、Z、A的指代同前面所述。 The specific steps include: (1)

and

Through the Suzuki reaction, we get

(2)

Through the reaction of organic lithium reagent with bromine, we can obtain

(3)

Reaction with ethyl propionate to obtain

; (4)

After catalytic cyclization,

; wherein, R ₁ , R _{2 ,} Z, and A have the same meanings as described above.

The above intermediates can be synthesized through public commercial channels or methods known in the literature.

The present invention provides a liquid crystal composition comprising the liquid crystal compound described in the present invention.

Preferably, the mass percentage of the liquid crystal compound in the liquid crystal composition is 1 to 60%, preferably 3 to 50%, and further preferably 5 to 25%.

The application of the composition containing the above-mentioned liquid crystal compound in the field of liquid crystal display is preferably in a liquid crystal display device, and the liquid crystal display device is further preferably a TN, ADS, VA, PSVA, FFS or IPS liquid crystal display.

The present invention has the following beneficial effects: the liquid crystal compound of the present invention has a large optical anisotropy △n, a lower rotational viscosity γ1, and a more excellent solubility while maintaining an appropriate negative dielectric anisotropy △ε and an appropriate clearing point Cp. It can improve the solubility of the liquid crystal composition, broaden the liquid crystal phase range of the liquid crystal composition, increase the operating temperature range of the liquid crystal display, and effectively shorten the response time of the liquid crystal display device.

The following embodiments are used to illustrate the present invention but are not intended to limit the scope of the present invention.

Unless otherwise specified, the raw materials mentioned above can be obtained from public commercial channels.

Implementation Example 1

This embodiment relates to a liquid crystal compound, the structural formula of which is:

The synthetic route for preparing compound BYLC-01 is as follows:

The specific steps are as follows:

(1) Synthesis of compound BYLC-01-1:

Under nitrogen protection, add 32.0g (0.15mol) 4-propyleneoxy-2,3-difluorophenylboric acid, 36.8g (0.15mol) 4-bromo-1-cyclopentylmethoxy-2-fluorobenzene, 180ml toluene, 90ml deionized water, 75ml ethanol, 16.0g anhydrous sodium carbonate, 0.6g tetrakistriphenylphosphine palladium to the reaction bottle, heat and reflux for 3 hours. Perform conventional post-treatment, chromatographic purification, n-hexane elution, and ethanol recrystallization to obtain 40g of white solid (compound BYLC-01-1), GC: 99.7%, yield: 80%.

(2) Synthesis of compound BYLC-01-2:

Under nitrogen protection, add 40.0g (0.12mol) BYLC-01-1 and 500ml tetrahydrofuran to the reaction bottle, control the temperature at -70~-80℃, add 0.14mol tert-butyl lithium n-hexane solution, keep the temperature for 1 hour, control the temperature at -70~-80℃, add 22g bromine, and then naturally return to -30℃. Add 500ml saturated sodium sulfite aqueous solution for hydrolysis and destruction, perform conventional post-treatment, and recrystallize from ethanol to obtain 41.3g of light yellow solid (compound BYLC-01-2), GC: 99.2%, yield 83.3%.

(3) Synthesis of compound BYLC-01-3:

Under nitrogen protection, add 41.3g (0.1mol) of compound BYLC-01-2, 18g of ethyl propionate, 24g of N,N-diisopropylethylamine, 0.5g of 2-dicyclohexylphosphino-2,4,6-triisopropylbiphenyl, 0.4g of tris(dibenzylideneacetone)dipalladium, 250ml of dioxane to the reaction bottle, and react for 6 hours at 90℃~100℃. Perform routine post-treatment, chromatographic purification, and n-hexane elution to obtain 39.6g of light yellow liquid (compound BYLC-01-3), GC: 97.5%, yield: 85%.

(4) Synthesis of compound BYLC-01:

Under nitrogen protection, add 39.6g (0.85mol) of compound BYLC-01-3, 10g of potassium tert-butoxide, and 300ml of tetrahydrofuran to the reaction bottle, and react at 65℃~70℃ for 6 hours. Perform routine post-treatment, chromatographic purification, n-hexane elution, and ethanol crystallization to obtain 22g of white solid (compound BYLC-01), GC: 99.8%, yield: 75%.

The obtained white solid BYLC-01 was analyzed by GC-MS, and the m/z of the product was 346.4 (M+).

Elemental analysis: C, 65.88; H, 4.66; O, 9.24; F, 10.97, S, 9.26.

Example 2

This embodiment relates to a liquid crystal compound, the structural formula of which is:

The synthetic route for preparing compound BYLC-02 is as follows:

The specific steps are as follows:

(1) Synthesis of compound BYLC-02-1:

Under nitrogen protection, add 45.6g (0.2mol) 4-butenyloxy-2,3-difluorophenylboric acid, 51.8g 4-bromo-1-cyclobutylmethoxy-2-fluorobenzene, 220ml toluene, 130ml deionized water, 90ml ethanol, 23.3g anhydrous sodium carbonate, 0.8g tetrakistriphenylphosphine palladium to the reaction bottle, heat and reflux for 3 hours. Perform conventional post-treatment, chromatographic purification, n-hexane elution, and ethanol recrystallization to obtain 60.16g of white solid (compound BYLC-02-1), GC: 99.5%, yield: 83%.

(2) Synthesis of compound BYLC-02-2:

Under nitrogen protection, add 54.4g (0.15mol) BYLC-02-1 and 500ml tetrahydrofuran to the reaction bottle, control the temperature at -70~-80℃, add 0.16mol tert-butyl lithium n-hexane solution, keep the temperature for 1 hour, control the temperature at -70~-80℃, add 26.4g bromine, and then naturally return to -30℃. Add 600ml saturated sodium sulfite aqueous solution for hydrolysis and destruction, perform conventional post-treatment, and recrystallize from ethanol to obtain 53g of light yellow solid (compound BYLC-02-2), GC: 99.5%, yield 80%.

(3) Synthesis of compound BYLC-02-3:

Under nitrogen protection, add 53.0g (0.12mol) of compound BYLC-02-2, 26.8g of ethyl propionate, 28.5g of N,N-diisopropylethylamine, 0.7g of 2-dicyclohexylphosphino-2,4,6-triisopropylbiphenyl, 0.5g of tris(dibenzylideneacetone)dipalladium, 300ml of dioxane to the reaction bottle, and control the temperature at 90 ℃~100℃ for 6 hours. Perform routine post-treatment, chromatographic purification, and n-hexane elution to obtain 49.4g of light yellow liquid (compound BYLC-02-3), GC: 96.7%, yield: 83.3%.

(4) Synthesis of compound BYLC-02:

Under nitrogen protection, add 49.4g (0.1mol) of compound BYLC-02-3, 15.6g of potassium tert-butoxide, and 400ml of tetrahydrofuran to the reaction bottle, and react at 65℃~70℃ for 6 hours. Perform routine post-treatment, chromatographic purification, n-hexane elution, and ethanol crystallization to obtain 30g of white solid (compound BYLC-02), GC: 99.8%, yield: 80%.

The obtained white solid BYLC-02 was analyzed by GC-MS, and the m/z of the product was 374.4 (M+).

Elemental analysis: C, 67.36; H, 5.38; O, 8.55; F, 10.15, S, 8.56.

According to the technical schemes of Example 1 and Example 2, the following liquid crystal compounds can be synthesized by simply replacing the corresponding raw materials without changing any substantial operations.

Implementation Example 3

The obtained white solid BYLC-03 was analyzed by GC-MS, and the m/z of the product was 360.4 (M+).

Example 4

The obtained white solid BYLC-04 was analyzed by GC-MS, and the m/z of the product was 360.4 (M+).

Example 5

The obtained white solid BYLC-05 was analyzed by GC-MS, and the m/z of the product was 374.47 (M+).

Example 6

The obtained white solid BYLC-06 was analyzed by GC-MS, and the m/z of the product was 402.49 (M+).

Example 7

The obtained white solid BYLC-07 was analyzed by GC-MS, and the m/z of the product was 430.5 (M+).

Example 8

The obtained white solid BYLC-08 was analyzed by GC-MS, and the m/z of the product was 360.4 (M+).

Example 9

The obtained white solid BYLC-09 was analyzed by GC-MS, and the m/z of the product was 362.4 (M+).

Comparative Example 1

The structure of the compound involved in this comparative example is:

Experimental example

This experimental example involves the determination of relevant properties of the compounds described in the examples and comparative examples.

According to the conventional testing methods in this field, △ε is tested by INSTEC liquid crystal testing instrument, γ1 is tested by viscometer, △n is tested by Abbe refractometer, and Cp is tested by differential thermal scanner.

The various performance parameters of the liquid crystal compound are obtained through linear fitting, where the specific meanings of the performance parameters are as follows: △n represents optical anisotropy (25℃); △ε represents dielectric anisotropy (25℃, 1000Hz); γ1 represents rotational viscosity (mPa.s, 25℃); Cp represents clearing point.

The performance parameter data of the compound prepared in the embodiment and the liquid crystal compound in the comparative example were compared and collated, and the test results are shown in Table 1:

It can be clearly seen from the test results in Table 1 that compared with the traditional negative dielectric anisotropy compounds with similar chemical structures, the liquid crystal compounds provided by the present invention have a larger optical anisotropy △n, a lower rotational viscosity γ1, and a better mutual solubility while maintaining an appropriate negative dielectric anisotropy △ε and an appropriate clearing point Cp. It can improve the mutual solubility of the liquid crystal composition, broaden the liquid crystal phase range of the liquid crystal composition, increase the operating temperature range of the liquid crystal display, and effectively shorten the response time of the liquid crystal display device.

Although the present invention has been described in detail above by general explanation, specific implementation methods and tests, it is obvious to those skilled in the art that some modifications or improvements can be made to the present invention. Therefore, these modifications or improvements made without departing from the spirit of the present invention are within the scope of protection claimed by the present invention.

Claims (9)

A liquid crystal composition is characterized by a liquid crystal compound having a structure represented by general formula (I):

In the general formula (I), _R1 represents H, an alkenyl group having 2-12 carbon atoms, or an alkenyloxy group having 2-12 carbon atoms; wherein one or more hydrogens in the alkenyl group having 2-12 carbon atoms or the alkenyloxy group having 2-12 carbon atoms may be optionally substituted by a halogen; Z represents a single bond, -O- or _-OCH2- ; A represents a cyclobutyl group or a cyclohexyl group; and _R2 represents H, or an alkyl group having 1-12 carbon atoms. The liquid crystal composition as described in claim 1, wherein R ₁ represents an alkenyloxy group having 2 to 7 carbon atoms; and R ₂ represents H or an alkyl group having 1 to 7 carbon atoms. A liquid crystal composition as described in claim 2, wherein R ₁ represents an alkenyloxy group having 2 to 7 carbon atoms, and the oxygen in the alkenyloxy group is connected to the carbon atom on the benzene ring in the general formula (I). The liquid crystal composition according to claim 1, wherein the liquid crystal compound is selected from one or more of the following structures:

A method for preparing a liquid crystal compound of the liquid crystal composition of any one of claims 1 to 4, wherein the synthesis route is as follows:

Specifically, the steps include: (1)

and

Through the Suzuki reaction, we get

(2)

Through the reaction of organic lithium reagent with bromine, we can obtain

(3)

Reaction with ethyl propionate to obtain

; (4)

After catalytic cyclization,

; wherein R ₁ , R _{2 ,} Z, and A have the same meanings as those described in any one of claim 1 to claim 3. A liquid crystal composition, comprising a liquid crystal compound as described in any one of claims 1 to 4. The liquid crystal composition as described in claim 6, wherein the mass percentage of the liquid crystal compound in the liquid crystal composition is 1-60%. An application in the field of liquid crystal display, which contains the liquid crystal compound described in any one of claims 1 to 4 or the liquid crystal composition described in claim 6 or 7. The application as described in claim 8, wherein the liquid crystal display field is a liquid crystal display device, and the liquid crystal display device is a TN, ADS, VA, PSVA, FFS or IPS liquid crystal display.