TW202225387A - Liquid crystal compound, preparation method therefor, and application thereof - Google Patents

Abstract

The present invention relates to the technical field of liquid crystal compounds, and specifically, to a liquid crystal compound, a preparation method therefor, and an application thereof. The liquid crystal compound has the structure shown in general formula (I). The liquid crystal compound of the present invention has large optical anisotropy [Delta]n and lower rotational viscosity [gamma]1 while maintaining appropriate negative dielectric anisotropy [Delta][epsilon] and an appropriate clearing point Cp, the intersolubility of a liquid crystal composition can be improved, the liquid crystal phase range of the liquid crystal composition is widened, the working temperature range of a liquid crystal display is increased, and the response time of a liquid crystal display device is effectively shortened.

Description

A kind of liquid crystal compound and its preparation method and application

The invention belongs to the technical field of liquid crystal compounds, and particularly relates to a liquid crystal compound and a preparation method and application thereof.

The application of liquid crystal materials as environmental materials in information display materials, organic optoelectronic materials and other fields has great research value and bright application prospects. Liquid crystal materials have many advantages as new display materials, such as extremely low power consumption and low driving voltage. At the same time, compared with other materials, it also has the advantages of small size, light weight, long life, large amount of displayed information, no electromagnetic radiation, etc. It can almost meet the requirements of various information display, especially in TFT-LCD (Thin Film Transistor Technology) products aspect.

In the TFT active matrix system, there are mainly TN (Twisted Nematic, twisted nematic structure) mode, IPS (In-Plane Switching, plane switching) mode, FFS (Fringe Field Switching, fringe field switching technology) mode and VA ( Vertical Alignment, vertical orientation) mode and other main display modes.

At present, TFT-LCD product technology has matured, successfully solving technical problems such as viewing angle, resolution, color saturation and brightness. Large- and small-sized TFT-LCD displays have gradually occupied the mainstream position of flat-panel displays in their respective fields. For dynamic image display applications, in order to achieve high-quality display and eliminate image afterimage and trailing, the liquid crystal material is required to have a fast response speed. This requires the liquid crystal material to have a rotational viscosity γ1 as low as possible. In addition, in order to reduce the power consumption of the liquid crystal display device, the driving voltage of the liquid crystal needs to be as low as possible, so it is required to increase the dielectric anisotropy Δε of the liquid crystal.

As the core functional material of liquid crystal display devices, liquid crystal materials are required to have a wide range of performance parameters in order to meet the requirements of various performance parameters of liquid crystal display devices and adapt to the technological requirements of liquid crystal display devices. On the basis of the dielectric anisotropy Δε of the liquid crystal, it also needs to have suitable optical anisotropy and a higher cooling point. In order to improve the properties of materials and adapt them to new requirements, the synthesis of new liquid crystal compounds and the study of structure-property relationship have become an important work in the field of liquid crystals.

The first object of the present invention is to provide a new type of liquid crystal compound 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 the structure represented by the general formula (I):

In the general formula (I), R ₁ represents H, an alkenyl group having 2-12 carbon atoms or an alkenyloxy group having 2-12 carbon atoms; wherein, the alkene having 2-12 carbon atoms One or more hydrogens in a radical or an alkenyloxy group having 2-12 carbon atoms may be optionally substituted by halogen, and one or more -CH2- may be independently replaced by -C≡C-, -CH= CH-, -CF=CF-, -CF=CH-, -COO-, -OCO- or -O- substitution;

Z represents a single bond, -O- or -OCH ₂ -;

A stands for single bond, cyclobutyl, cyclopropyl, cyclohexyl

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

Preferably, in the general formula (I), the R ₁ represents an alkenyloxy group having 2-7 carbon atoms;

R ₂ 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, the R ₁ 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 liquid crystal compound that meets the technological requirements of the liquid crystal display device of the present invention is for the purpose of research and development.

On the basis of the main structure, the left side is further supplemented with alkenyloxy end groups, and the right side is supplemented with other groups, which not only has a suitable negative dielectric anisotropy Δε and a suitable clearing point Cp, but also reduces the rotational viscosity γ1, making the liquid crystal The response time of the display device is effectively shortened.

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 the preparation method of above-mentioned liquid crystal compound, and its synthetic route is as follows:

Specifically include the following steps:

與

通過suzuki反應，得到 (1) with

and

Through the suzuki reaction, we get

通過有機鋰試劑，與溴素反應，得到 (2)

Through organolithium reagent, react with bromine to obtain

與巰基丙酸乙酯反應，得到

； (3)

Reaction with ethyl mercaptopropionate to obtain

;

經催化合環，得到

； (4)

After catalytic ring closure, we get

;

Wherein, the designations of R ₁ , R _{2 ,} Z, and A are the same as those described in any one of claims 1 to 3 .

The above-mentioned intermediates can be synthesized through public commercial routes 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 of the present invention.

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

The fourth object 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 the application of liquid crystal display device, and the liquid crystal display device is more preferably TN, ADS, VA , PSVA, FFS or IPS LCD monitor.

The present invention has the following beneficial effects:

The liquid crystal compound of the present invention has larger optical anisotropy Δn, lower rotational viscosity γ1 and better mutual solubility while maintaining proper negative dielectric anisotropy Δε and proper clearing point Cp can improve the mutual solubility of the liquid crystal composition, widen the liquid crystal phase range of the liquid crystal composition, increase the working temperature range of the liquid crystal display, and effectively shorten the response time of the liquid crystal display device.

The following examples are intended to illustrate the present invention, but not to limit the scope of the present invention.

The raw materials can be obtained from open commercial sources unless otherwise specified.

Example 1

This embodiment relates to a liquid crystal compound whose structural formula is:

The synthetic route for the preparation of compound BYLC-01 is shown below:

Specific steps are as follows:

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

Under nitrogen protection, 32.0g (0.15mol) of 4-propenyloxy-2,3-difluorophenylboronic acid, 36.8g (0.15mol) of 4-bromo-1-cyclopentylmethoxy-2- Fluorobenzene, 180 ml of toluene, 90 ml of deionized water, 75 ml of ethanol, 16.0 g of anhydrous sodium carbonate, and 0.6 g of tetrakistriphenylphosphine palladium were heated and refluxed for 3 hours. Routine post-treatment was carried out, purified by chromatography, eluted with n-hexane, and recrystallized with ethanol to obtain 40 g of white solid (compound BYLC-01-1), GC: 99.7%, yield: 80%.

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

Under nitrogen protection, 40.0g (0.12mol) BYLC-01-1 and 500ml tetrahydrofuran were added to the reaction flask, and the n-hexane solution of 0.14mol tert-butyllithium was added dropwise under temperature control at -70~-80°C. , temperature control -70~-80℃, add 22g bromine dropwise, and then return to -30℃ naturally. 500ml of saturated aqueous sodium sulfite solution was added to carry out hydrolysis destruction, conventional post-treatment was performed, and ethanol was recrystallized to obtain 41.3 g of light yellow solid (compound BYLC-01-2), GC: 99.2%, yield 83.3%.

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

Under nitrogen protection, 41.3g (0.1mol) compound BYLC-01-2, 18g ethyl mercaptopropionate, 24g N,N-diisopropylethylamine, 0.5g 2-dicyclohexylphosphine- 2,4,6-triisopropylbiphenyl, 0.4g tris(dibenzylideneacetone)dipalladium, 250ml dioxane, and react at a temperature of 90°C to 100°C for 6 hours. Carry out routine post-treatment, chromatographic purification, n-hexane elution to obtain 39.6 g of pale yellow liquid (compound BYLC-01-3), GC: 97.5%, yield: 85%.

(4) Synthesis of compound BYLC-01:

Under nitrogen protection, 39.6 g (0.85 mol) of compound BYLC-01-3, 10 g of potassium tert-butoxide and 300 ml of tetrahydrofuran were added to the reaction flask, and the reaction was carried out at 65°C to 70°C for 6 hours. routine post-processing The solution was purified by chromatography, eluted with n-hexane, and crystallized with ethanol to obtain 22 g of a white solid (compound BYLC-01), GC: 99.8%, yield: 75%.

The resulting white solid BYLC-01 was analyzed by GC-MS and the product had m/z of 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 whose structural formula is:

The synthetic route for the preparation of compound BYLC-02 is shown below:

Specific steps are as follows:

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

Under nitrogen protection, 45.6g (0.2mol) of 4-butenyloxy-2,3-difluorobenzeneboronic acid, 51.8g of 4-bromo-1-cyclobutanmethoxy-2-fluorobenzene were added to the reaction flask, 220ml of toluene, 130ml of deionized water, 90ml of ethanol, 23.3g of anhydrous sodium carbonate, 0.8g of tetrakistriphenylphosphine palladium, heated and refluxed for 3 hours. Routine post-treatment was carried out, purified by chromatography, eluted with n-hexane, and recrystallized with ethanol to obtain 60.16 g of a white solid (compound BYLC-02-1), GC: 99.5%, yield: 83%.

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

Under nitrogen protection, 54.4g (0.15mol) BYLC-02-1, 500ml tetrahydrofuran were added to the reaction flask, and the n-hexane solution of 0.16mol tert-butyllithium was added dropwise under temperature control at -70~-80°C, and the reaction was incubated for 1 hour after dropping. , 26.4g of bromine was added dropwise under temperature control -70~-80℃, and then the temperature was naturally returned to -30℃. Add 600ml of saturated aqueous sodium sulfite solution for hydrolysis destruction, carry out routine post-treatment, and recrystallize from ethanol to obtain 53 g 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) compound BYLC-02-2, 26.8g ethyl mercaptopropionate, 28.5g N,N-diisopropylethylamine, 0.7g 2-dicyclohexyl to the reaction flask Phosphine-2,4,6-triisopropylbiphenyl, 0.5 g of tris(dibenzylideneacetone)dipalladium, 300 ml of dioxane, and react at a temperature of 90°C to 100°C for 6 hours. Carry out conventional post-treatment, chromatographic purification, n-hexane elution to obtain 49.4 g of pale yellow liquid (compound BYLC-02-3), GC: 96.7%, yield: 83.3%.

(4) Synthesis of compound BYLC-02:

Under nitrogen protection, 49.4 g (0.1 mol) of compound BYLC-02-3, 15.6 g of potassium tert-butoxide, and 400 ml of tetrahydrofuran were added to the reaction flask, and the reaction was carried out at 65°C to 70°C for 6 hours. Carry out routine post-treatment, chromatographic purification, n-hexane elution, ethanol crystallization to obtain 30 g of white solid (compound BYLC-02), GC: 99.8%, yield: 80%.

The resulting 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 solutions of Example 1 and Example 2, the following liquid crystal compounds can be synthesized by simply replacing the corresponding raw materials without changing any substantive operation.

Example 3

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

Example 4

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

Example 5

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

Example 6

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

Example 7

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

Example 8

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

Example 9

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

Comparative Example 1

The structures of the compounds involved in this comparative example are:

Experimental example

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

According to the conventional detection methods in the art, for example, Δε is detected by INSTEC liquid crystal detection instrument, γ1 is detected by viscometer, Δn is detected by Abbe refractometer, and Cp is detected by differential calorimeter.

Various performance parameters of the liquid crystal compound are obtained by linear fitting, wherein the specific meanings of each performance parameter are as follows:

Δn represents optical anisotropy (25°C); Δε represents dielectric anisotropy (25°C, 1000Hz); γ1 represents rotational viscosity (mPa·s, 25°C); Cp represents clearing point.

The compounds prepared in the examples were compared with the liquid crystal compound performance parameter data of the comparative examples, and the test results were 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 maintain a proper negative dielectric anisotropy. At the same time of Δε and appropriate clearing point Cp, it has larger optical anisotropy Δn, lower rotational viscosity γ1, and better mutual solubility, which can improve the mutual solubility of liquid crystal compositions and broaden the liquid crystal composition of liquid crystal compositions. The phase range is increased, the operating temperature range of the liquid crystal display is increased, and the response time of the liquid crystal display device is effectively shortened.

Although the present invention has been described in detail above with general description, specific embodiments and tests, some modifications or improvements can be made on the basis of the present invention, which is obvious to those skilled in the art . Therefore, these modifications or improvements made without departing from the spirit of the present invention fall within the scope of the claimed protection of the present invention.

Claims (9)

A liquid crystal compound, characterized in that it has the structure shown in the general formula (I):

In the general formula (I), R ₁ represents H, an alkenyl group having 2-12 carbon atoms or an alkenyloxy group having 2-12 carbon atoms; wherein, the alkene having 2-12 carbon atoms One or more hydrogens in a radical or an alkenyloxy group having 2-12 carbon atoms may be optionally substituted by halogen, and one or more -CH ₂ - may each independently be replaced by -C≡C-, -CH =CH-, -CF=CF-, -CF=CH-, -COO-, -OCO- or -O- substituted; Z represents a single bond, -O- or -OCH ₂ -; A represents single bond, cyclobutyl, cyclopropyl, cyclohexyl; R ₂ represents H, an alkyl group having 1-12 carbon atoms, an alkenyl group having 2-12 carbon atoms or an alkenyloxy group having 2-12 carbon atoms. The liquid crystal compound according to claim 1, wherein the R ₁ represents an alkenyloxy group having 2-7 carbon atoms; R ₂ represents H, 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. The liquid crystal compound according to claim 2, wherein the R ₁ represents an alkenyloxy group having 2 to 7 carbon atoms, and the oxygen in the alkenyloxy group is the same as the carbon atom on the benzene ring in the general formula (I). connected. The liquid crystal compound according to claim 1, wherein the liquid crystal compound is selected from one or more of the following structures:

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

Specifically include the following steps: (1) with

and

Through the suzuki reaction, we get

(2)

Through organolithium reagent, react with bromine to obtain

(3)

Reaction with ethyl mercaptopropionate to obtain

; (4)

After catalytic ring closure, we get

; Wherein, the designations of R ₁ , R _{2 ,} Z, and A are the same as those described in any one of claims 1 to 3 . A liquid crystal composition comprising the liquid crystal compound according to any one of claims 1 to 4. The liquid crystal composition according to claim 6, wherein the mass percentage of the liquid crystal compound in the liquid crystal composition is 1 to 60%, preferably 3 to 50%, and more preferably 5 to 25%. An application in the field of liquid crystal display, which contains the liquid crystal compound according to any one of claims 1 to 4 or the liquid crystal composition according to claim 6 or 7. The application according to claim 8, wherein the liquid crystal display field is a liquid crystal display device, preferably, the liquid crystal display device is a TN, ADS, VA, PSVA, FFS or IPS liquid crystal display.