WO2022116826A1 - Liquid crystal compound and method for preparation thereof and application thereof - Google Patents

Abstract

The present invention belongs to the technical field of liquid crystal compounds, and specifically relates to a liquid crystal compound and method for preparation thereof and application thereof. The liquid crystal compound has the structure shown in the general formula (I). The liquid crystal compound of the present invention maintains an appropriate negative dielectric anisotropy Δε and an appropriate clearing point Cp, and has large optical anisotropy Δn, relatively low rotational viscosity γ1, and better mutual solubility, and can improve the mutual solubility of liquid crystal compositions, broaden the liquid crystal phase range of liquid crystal compositions, increase the operating temperature range of a liquid crystal display, and effectively shorten the response time of a liquid crystal display device.

Description

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

cross reference

This application claims the priority of Chinese Patent Application No. 202011389353.7 filed on December 1, 2020 and entitled "A Liquid Crystal Compound and Its Preparation and Application", the entire disclosure of which is incorporated herein by reference in its entirety.

technical field

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.

Background technique

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, so the liquid crystal material is required to have as low a rotational viscosity γ1 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.

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 technological requirements of liquid crystal display devices, liquid crystal materials are required to have a wide range of performance parameters, especially to reduce the rotational viscosity of liquid crystal materials. γ1 and increase the optical anisotropy Δn of the liquid crystal material. 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.

SUMMARY OF THE INVENTION

The first objective of the present invention is to provide a new type of liquid crystal compound to improve the deficiencies of existing liquid crystal materials and to 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 represents H, an alkenyl group having 2-12 carbon atoms or an alkenyloxy group having 2-12 carbon atoms; wherein, the alkenyl group having 2-12 carbon atoms Or one or more hydrogens in 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- substitution, but require that the O atoms are not directly connected to each other;

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

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

Preferably, the structural formula of the liquid crystal compound is (Ia) or (Ib):

As shown in the formula, R has the same definition as above.

The liquid crystal compound that meets the technological requirements of the liquid crystal display device in 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 an alkenyloxy end group, and the right side is supplemented with a cyclopentyl end group, which not only has a suitable negative dielectric anisotropy Δε and a suitable clearing point Cp, but also has a suitable optical anisotropy. The increase in the anisotropy Δn and the decrease in the rotational viscosity γ1 can effectively shorten 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 the preparation method of above-mentioned liquid crystal compound, and its synthetic 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, R and Z in the compound involved in each step correspond to the groups represented by R and Z in the obtained liquid crystal compound product (see the definition of each substituent in the general formula I).

the above

All of them can be synthesized through open 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 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.

Detailed ways

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

Unless otherwise specified, the raw materials can be obtained from open commercial sources (for example, provided by Beijing Bayi Shikong).

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, add 32.0g 4-propenyloxy-2,3-difluorobenzeneboronic acid, 40.8g 4-bromo-1-cyclopentylmethoxy-2-fluorobenzene, 180ml toluene, 90ml deionized benzene to the reaction flask Water, 75 ml of ethanol, 16.0 g of anhydrous sodium carbonate, 0.6 g of tetrakistriphenylphosphine palladium, and heated to reflux for 3 hours. Carry out routine post-treatment, chromatographic purification, n-hexane elution, and ethanol recrystallization to obtain 42.7 g of white solid (compound BYLC-01-1), GC: 99.6%, yield: 78.8%.

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

Under nitrogen protection, 40.0g 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 at a temperature of -70 to -80°C. 22.8 g of bromine was added dropwise at 70 to -80°C, and then the temperature was naturally returned to -30°C. 500ml of saturated aqueous sodium sulfite solution was added for hydrolysis and destruction, and conventional post-treatment was carried out. The ethanol was recrystallized to obtain 38.7g of light yellow solid (compound BYLC-01-2), GC: 99.2%, yield 79.8%.

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

Under nitrogen protection, 38.0g of compound BYLC-01-2, 15.5g of ethyl mercaptopropionate, 20.6g of N,N-diisopropylethylamine, 0.5g of 2-dicyclohexylphosphine-2 were added to the reaction flask, 4,6-triisopropylbiphenyl, 0.4 g of tris(dibenzylideneacetone)dipalladium, 250 ml of dioxane, and the temperature was controlled at 90°C to 100°C to react for 6 hours. Carry out routine post-treatment, chromatographic purification, n-hexane elution to obtain 36.3 g of pale yellow liquid (compound BYLC-01-3), GC: 97.5%, yield: 85.2%.

(4) Synthesis of compound BYLC-01:

Under nitrogen protection, 36.0 g of compound BYLC-01-3, 9.8 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. Carry out routine post-treatment, chromatographic purification, n-hexane elution, ethanol crystallization to obtain 21.7 g of white solid (compound BYLC-01), GC: 99.8%, yield: 75.5%.

The resulting white solid BYLC-01 was analyzed by GC-MS and the product had m/z of 374.1 (M+).

Elemental analysis: C, 67.36; H, 5.37; O, 8.55; F, 10.16, S, 8.56.

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 of 4-butenyloxy-2,3-difluorobenzeneboronic acid, 55.0g of 4-bromo-1-cyclopentylmethoxy-2-fluorobenzene, 220ml of toluene, 130ml of Ionized water, 90 ml of ethanol, 23.3 g of anhydrous sodium carbonate, and 0.8 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 61.3 g of white solid (compound BYLC-02-1), GC: 99.4%, yield: 81.6%.

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

Under nitrogen protection, 60.0g BYLC-02-1 and 500ml tetrahydrofuran were added to the reaction flask, and the n-hexane solution of 0.20mol tert-butyllithium was added dropwise at a temperature of -70 to -80°C. 32.0 g of bromine was added dropwise at 70 to -80°C, and then the temperature was naturally returned to -30°C. 600ml of saturated aqueous sodium sulfite solution was added for hydrolysis and destruction, and routine post-treatment was carried out. The ethanol was recrystallized to obtain 58.3 g of a light yellow solid (compound BYLC-02-2), GC: 99.4%, yield 80.5%.

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

Under nitrogen protection, 58.0g of compound BYLC-02-2, 21.5g of ethyl mercaptopropionate, 28.5g of N,N-diisopropylethylamine, 0.7g of 2-dicyclohexylphosphine-2, 0.7g were added to the reaction flask, 4,6-triisopropylbiphenyl, 0.5 g of tris(dibenzylideneacetone)dipalladium, 300 ml of dioxane, and the temperature was controlled at 90°C to 100°C to react for 6 hours. Carry out conventional post-treatment, chromatographic purification, n-hexane elution to obtain 54.0 g of pale yellow liquid (compound BYLC-02-3), GC: 96.6%, yield: 83.2%.

(4) Synthesis of compound BYLC-02:

Under nitrogen protection, 54.0 g of compound BYLC-02-3, 15.5 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 31.6 g of white solid (compound BYLC-02), GC: 99.7%, yield: 76.8%.

The resulting white solid, BYLC-02, was analyzed by GC-MS, and the m/z of the product was 388.1 (M+).

Elemental analysis: C, 68.02; H, 5.71; O, 8.25; F, 9.77, S, 8.25.

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 product had m/z of 402.1 (M+).

Elemental analysis: C, 68.63; H, 6.01; O, 7.95; F, 9.45; S, 7.96.

Example 4

The resulting white solid BYLC-04 was analyzed by GC-MS and the product had m/z of 374.1 (M+).

Elemental analysis: C, 67.36; H, 5.38; O, 8.55; F, 10.14; S, 8.56.

Example 5

The resulting white solid, BYLC-05, was analyzed by GC-MS, and the m/z of the product was 402.1 (M+).

Elemental analysis: C, 68.62; H, 6.02; O, 7.95; F, 9.44; S, 7.97.

Example 6

The resulting white solid BYLC-06 was analyzed by GC-MS and the product had m/z of 416.1 (M+).

Elemental analysis: C, 69.21; H, 6.29; O, 7.68; F, 9.12; S, 7.70.

Example 7

The resulting white solid BYLC-07 was analyzed by GC-MS and the product had m/z of 430.1 (M+).

Elemental analysis: C, 69.74; H, 6.55; O, 7.43; F, 8.83; S, 7.45.

Example 8

The resulting white solid BYLC-08 was analyzed by GC-MS and the product had m/z of 416.1 (M+).

Elemental analysis: C, 69.20; H, 6.29; O, 7.69; F, 9.13; S, 7.72.

Example 9

The resulting white solid BYLC-09 was analyzed by GC-MS and the product had m/z of 388.1 (M+).

Elemental analysis: C, 68.01; H, 5.72; O, 8.27; F, 9.75, S, 8.23.

Comparative Example 1

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

Comparative Example 2

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

Comparative Example 3

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

Comparative Example 4

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

As a result, it was found that the liquid crystal compound shown in Comparative Example 4 was structurally unstable.

Experimental example

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

According to 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 performance parameter data of the liquid crystal compounds of the comparative examples, and the test results were shown in Table 1:

Table 1: Performance test results of liquid crystal compounds

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.

Industrial Applicability

The present invention provides a liquid crystal compound and its preparation method and application. The liquid crystal compound has a structure represented by the general formula (I). 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, which has good economic value and application prospect.

Claims (9)

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

   

   In the general formula (I), R represents H, an alkenyl group having 2-12 carbon atoms or an alkenyloxy group having 2-12 carbon atoms; wherein, the alkenyl group having 2-12 carbon atoms Or one or more hydrogens in 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- substitution, but require that the O atoms are not directly connected to each other;

   Z represents a single bond, -O- or -OCH ₂ -.
2. The liquid crystal compound according to claim 1, wherein the R represents an alkenyloxy group having 2 to 7 carbon atoms.
3. The liquid crystal compound according to claim 1 or 2, wherein the structural formula of the liquid crystal compound is (Ia) or (Ib):

   

   As shown in the formula, R is as defined in claim 1 or 2.
4. The liquid crystal compound according to claim 1, wherein the liquid crystal compound is selected from one or more of the following structures:

   

   
5. A method for preparing the liquid crystal compound according to 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 designation of R and Z is the same as that described in any one of claims 1-4.
6. A liquid crystal composition, characterized by comprising the liquid crystal compound according to any one of claims 1 to 4.
7. The liquid crystal composition according to claim 6, wherein the mass percentage of the liquid crystal compound in the liquid crystal composition is 1-60%, preferably 3-50%, more preferably 5-25%.
8. Application of the liquid crystal compound of any one of claims 1 to 4 or the liquid crystal composition of claim 6 or 7 in the field of liquid crystal display.
9. 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.