TW202214583A - A kind of thiophene-containing acetylene liquid crystal compound and its preparation method and application Having high optical anisotropy and low rotational viscosity - Google Patents

Abstract

The invention belongs to the technical field of liquid crystal materials, and in particular relates to a thiophene-containing acetylene liquid crystal compound and a preparation method and application thereof. The thiophene-containing acetylene liquid crystal compound has a structure represented by the general formula (I), which has high optical anisotropy and low rotational viscosity, thus the response time can be shortened.

Description

A kind of acetylene liquid crystal compound containing thiophene and its preparation method and application

The invention belongs to the technical field of liquid crystal materials, and in particular relates to a thiophene-containing acetylene liquid crystal compound and a preparation method and application thereof.

At present, liquid crystals are widely used in the field of information display, and some progress has also been made in the application of optical communication (S.T.Wu, D.K.Yang.Reflective Liquid Crystal Displays.Wiley, 2001). In recent years, the application fields of liquid crystal compounds have been significantly expanded to various display devices, electro-optical devices, electronic components, sensors, and the like. To this end, many different structures have been proposed, especially in the field of nematic liquid crystals, which have so far been the most widely used in flat panel displays.

According to the use requirements of liquid crystal display devices, liquid crystal materials have certain requirements, wide nematic temperature range, low driving voltage, suitable optical anisotropy, and excellent chemical optical stability. Liquid crystal compounds cannot meet the above requirements at the same time, and liquid crystal compounds with different properties are required to be mixed together to meet commercial requirements.

For liquid crystal media, a fast response time is required, and reducing the thickness of the liquid crystal can shorten the response time, which requires a high optical anisotropy constant Δn to ensure sufficient optical retardation value d*Δ n, however, liquid crystals with high optical permittivity Δn generally have high rotational viscosity, which in turn leads to longer response times.

Therefore, it is particularly important to find single crystal compounds with low viscosity and high optical anisotropy.

Alkyne liquid crystals are highly conjugated molecules with large Δn and high-definition bright spots. As an important component, they can improve the Δn and clearing points of mixed liquid crystals, and increase the response speed. Alkyne liquid crystals have been widely used in TN, STN and molecular Liquid crystal material for antenna.

The first object of the present invention is to provide a novel thiophene-containing acetylene liquid crystal compound, which has high optical anisotropy and low rotational viscosity, and can shorten the response time.

The acetylene-based liquid crystal compound containing thiophene has the structure represented by the general formula (I):

In the formula,

R ₁ and R ₂ each independently represent -H, -Cl, -F, -CN, -OCN, -OCF ₃ , -CF ₃ , -CHF ₂ , -CH ₂ F, -OCHF ₂ , -OCF=CF ₂ , -OCF ₂ CF ₃ , -SCN, -NCS, -SF ₅ , C ₁ -C ₁₅ alkyl, C ₁ -C ₁₅ alkoxy, C ₂ -C ₁₅ alkenyl or C ₂ -C ₁₅ alkenyloxy group, wherein one or more of the C ₁ -C ₁₅ alkyl group, C ₁ -C ₁₅ alkoxy group, C ₂ -C ₁₅ alkenyl group or C ₂ -C ₁₅ alkenyloxy group hydrogens can be optionally substituted by fluorine or chlorine, and one or more non-adjacent _-CH2- can be independently of each other by -CH=CH-, -C≡C-, -COO-, -OOC-, -O- or -S- substitution;

A ₁ and A ₂ each independently represent a single bond or one of the following groups:

Z ₁ and Z ₂ each independently represent a single bond, -CH ₂ -, -CH ₂ -CH ₂ -, -(CH ₂ ) ₃ -, -(CH ₂ ) ₄ -, -CH=CH-, -C≡ C-, -COO-, -OOC-, -OCH ₂ -, -CH ₂ O-, -CF ₂ O-, -OCF ₂ -, -CF ₂ CH ₂ -, -CH ₂ CF ₂ -, -C ₂ F ₄ -or -CF=CF-;

n=0, 1, 2, 3 or 4.

Preferably, in the above-mentioned acetylene liquid crystal compound containing thiophene, R ₁ and R ₂ each independently represent -H, -CF ₃ , -OCF ₃ , -CN, -NCS, C ₁ -C ₇ alkyl group or C ₁ -C ₇ alkoxy, and one or more hydrogens in said C ₁ -C ₇ alkyl or C ₁ -C ₇ alkoxy may be optionally substituted by fluorine or chlorine, more preferably by fluorine replace.

Preferably, in the above-mentioned acetylene liquid crystal compound containing thiophene, A1 and A2 each independently represent a single bond or one of the following groups:

Preferably, in the above-mentioned thiophene-containing acetylene liquid crystal compound, Z ₁ and Z ₂ each independently represent a single bond, -CH ₂ -, -CH ₂ -CH ₂ -, -(CH ₂ ) ₃ -, -(CH ₂ ) ₄ -, -COO-, -OOC-, -OCH ₂ -, -CH ₂ O-, -CF ₂ O- or -OCF ₂ -.

Preferably, in the above-mentioned acetylene liquid crystal compound containing thiophene, the compound represented by the general formula (I) is selected from one or more of the following structures:

The definitions of R ₁ , R ₂ and Z ₂ are the same as above.

Another object of the present invention is to provide the preparation method of the above-mentioned acetylene liquid crystal compound containing thiophene, and its synthetic route is as follows:

Specifically include the following steps:

Compound I-1-01 and compound I-1-02 are reacted under the action of triethylamine and palladium catalysts to obtain target compound I;

Wherein, the definitions of R ₁ , R ₂ , A ₁ , A ₂ , Z ₁ and Z ₂ in the compounds involved in the above steps are the same as above.

The third object of the present invention is to protect a liquid crystal composition containing the above-mentioned thiophene-containing acetylenic liquid crystal compound. Wherein, the addition amount of the above-mentioned thiophene-containing acetylenic liquid crystal compound is preferably 1-80%, more preferably 3-50%. Those skilled in the art can predict that the addition of the above-mentioned thiophene-containing acetylenic liquid crystal compound can further improve the optical anisotropy of the conventional liquid crystal composition, and has the technical effect of shortening the response time.

The fourth object of the present invention is to protect the application of the above-mentioned thiophene-containing acetylenic liquid crystal compound and the liquid crystal composition containing the above-mentioned thiophene-containing acetylenic liquid crystal compound in the field of liquid crystal display. Preferred is the application in liquid crystal display devices. The liquid crystal display device includes but is not limited to TN and STN liquid crystal displays. After the above-mentioned liquid crystal composition is applied to a liquid crystal display device, it has the advantage of shortening the response time.

The fifth object of the present invention is to protect the application of the above-mentioned thiophene-containing acetylenic liquid crystal compound and the liquid crystal composition containing the above-mentioned thiophene-containing acetylenic liquid crystal compound in the field of molecular antennas.

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

Unless otherwise specified, the percentages in the present invention are by weight; the temperature is in degrees Celsius.

Example 1

The synthetic route is as follows:

Add 25.6g (0.1mol) compound BYLC-01-1 (reactant), 20g BYLC-01-2 (reactant), 100ml toluene (solvent), 100ml triethylamine to the reaction flask, nitrogen protection, add 1g Triphenylphosphine palladium, heated under reflux for 6 hours, added 200ml of water, separated the layers, extracted the aqueous phase with 100ml of toluene (solvent), washed the organic phase with water until neutral, evaporated the solvent to obtain a pale yellow solid, weighed in 200ml of ethanol and 200ml of n-heptane 32.9 g of BYLC-01 were obtained by crystallization twice, the yield was 90%, and the gas chromatography purity was 99.8%.

Mass spectrometry fragment: 366 (molecular ion peak).

Example 2

The synthetic route is as follows:

Add 25.6g (0.1mol) compound BYLC-01-1 (reactant), 24g BYLC-02-1 (reactant), 100ml toluene (solvent), 100ml triethylamine to the reaction flask, nitrogen protection, add 1g Triphenylphosphine palladium, heated under reflux for 6 hours, added 200 ml of water, separated the layers, extracted the aqueous phase with 100 ml of toluene (solvent), washed the organic phase with water until neutral, evaporated the solvent to obtain a pale yellow solid, 200 ml of ethyl acetate 200ml of n-heptane alcohol was recrystallized twice to obtain 34.9g of BYLC-02, the yield was 86%, and the gas chromatography purity was 99.8%.

Mass spectrometry fragment: 406 (molecular ion peak).

Example 3

The synthetic route is as follows:

Add 34g (0.1mol) compound BYLC-01-1 (reactant), 20g BYLC-02-1 (reactant), 100ml toluene (solvent), 100ml triethylamine to the reaction flask, pass nitrogen protection, add 1g tetratriphenyl Phosphine palladium, heated under reflux for 6 hours, added 200ml of water, separated, extracted the aqueous phase with 100ml of toluene (solvent), washed the organic phase with water until neutral, evaporated the solvent to obtain a pale yellow solid, recrystallized from 200ml of ethanol and 200ml of n-heptane. 38.2g of BYLC-04 were obtained, the yield was 85%, and the gas chromatography purity was 99.8%.

Mass spectrometry fragment: 450 (molecular ion peak).

Example 4

The synthetic route is as follows:

Add 34.2g (0.1mol) compound BYLC-01-1 (reactant), 20g BYLC-02-1 (reactant), 100ml toluene (solvent), 100ml triethylamine to the reaction flask, nitrogen protection, add 1g Triphenylphosphine palladium, heated under reflux for 6 hours, added 200ml of water, separated the layers, extracted the aqueous phase with 100ml of toluene (solvent), washed the organic phase with water until neutral, evaporated the solvent to obtain a pale yellow solid, weighed in 200ml of ethanol and 200ml of n-heptane Crystallization twice to obtain 38g of BYLC-04, the yield is 84%, and the gas chromatography purity is 99.8%.

Mass spectrometry fragment: 452 (molecular ion peak).

Example 5

The synthetic route is as follows:

Add 25.6g (0.1mol) compound BYLC-01-1 (reactant), 24g BYLC-02-1 (reactant), 100ml toluene (solvent), 100ml triethylamine to the reaction flask, nitrogen protection, add 1g Triphenylphosphine palladium, heated under reflux for 6 hours, added 200ml of water, separated the layers, extracted the aqueous phase with 100ml of toluene (solvent), washed the organic phase with water until neutral, evaporated the solvent to obtain a pale yellow solid, weighed in 200ml of ethanol and 200ml of n-heptane Crystallization twice to obtain 34.5g BYLC-04, the yield is 85%, and the gas chromatography purity is 99.8%.

Mass spectrometry fragment: 406 (molecular ion peak).

Example 6

The synthetic route is as follows:

Add 23.8g (0.1mol) compound BYLC-06-1 (reactant), 20g BYLC-01-2 (reactant), 100ml toluene (solvent), 100ml triethylamine to the reaction flask, nitrogen protection, add 1g Triphenylphosphine palladium, heated under reflux for 6 hours, added 200ml of water, separated the layers, extracted the aqueous phase with 100ml of toluene (solvent), washed the organic phase with water until neutral, evaporated the solvent to obtain a pale yellow solid, weighed in 200ml of ethanol and 200ml of n-heptane Crystallization twice to obtain 31.2g BYLC-06, the yield is 90%, and the gas chromatography purity is 99.8%.

Mass spectrometry fragment: 348 (molecular ion peak).

Example 7

The synthetic route is as follows:

Add 21.8g (0.1mol) compound BYLC-07-1 (reactant), 20g BYLC-01-2 (reactant), 100ml toluene (solvent), 100ml triethylamine to the reaction flask, nitrogen protection, add 1g Triphenylphosphine palladium, heated under reflux for 6 hours, added 200ml of water, separated the layers, extracted the aqueous phase with 100ml of toluene (solvent), washed the organic phase with water until neutral, evaporated the solvent to obtain a pale yellow solid, weighed in 200ml of ethanol and 200ml of n-heptane Crystallization twice to obtain 29.7g BYLC-07, the yield is 90%, and the gas chromatography purity is 99.8%.

Mass spectrometry fragment: 330.1 (molecular ion peak).

Example 8

The synthetic route is as follows:

Add 25.6g (0.1mol) compound BYLC-01-1 (reactant), 20g BYLC-01-2 (reactant), 100ml toluene (solvent), 100ml triethylamine to the reaction flask, nitrogen protection, add 1g Triphenylphosphine palladium, heated under reflux for 6 hours, added 200ml of water, separated the layers, extracted the aqueous phase with 100ml of toluene (solvent), washed the organic phase with water until neutral, evaporated the solvent to obtain a pale yellow solid, weighed in 200ml of ethanol and 200ml of n-heptane Crystallization twice to obtain 31 g of BYLC-08, the yield is 85%, and the gas chromatography purity is 99.8%.

Mass spectrometry fragment: 366 (molecular ion peak).

Example 9

According to the technical solution of Example 2, it is only necessary to simply replace the corresponding raw materials without changing any substantive operation, and the liquid crystal compound of the following general structural formula can be synthesized.

The selection of R ₁ and R ₂ is shown in Table 1.

Example 10

According to the technical solution of Example 2, it is only necessary to simply replace the corresponding raw materials without changing any substantive operation, and the liquid crystal compound of the following general structural formula can be synthesized.

The selection of R ₁ and R ₂ is shown in Table 2.

Example 11

According to the technical solution of Example 3, it is only necessary to simply replace the corresponding raw materials without changing any substantive operation, and the liquid crystal compound of the following general structural formula can be synthesized.

The selection of R ₁ and R ₂ is shown in Table 3.

Example 12

According to the technical solution of Example 4, it is only necessary to simply replace the corresponding raw materials without changing any substantive operation, and the liquid crystal compound of the following general structural formula can be synthesized.

The selection of R ₁ and R ₂ is shown in Table 4.

Example 13

According to the technical solution of Example 1, it is only necessary to simply replace the corresponding raw materials without changing any substantive operation, and the liquid crystal compound of the following general structural formula can be synthesized.

The selection of R ₁ and R ₂ is shown in Table 5.

Example 14

According to the technical solution of Example 5, it is only necessary to simply replace the corresponding raw materials without changing any substantive operation, and the liquid crystal compound of the following general structural formula can be synthesized.

The selection of R ₁ , R ₂ and Z ₂ is shown in Table 6.

Example 15

According to the technical solution of Example 5, it is only necessary to simply replace the corresponding raw materials without changing any substantive operation, and the liquid crystal compound of the following general structural formula can be synthesized.

The selection of R ₁ , R ₂ , A ₁ , and Z ₂ is shown in Table 7.

Experimental example

This experimental example involves the determination of the relevant properties of the compounds described in Examples 1 to 8.

According to the conventional detection methods in the art, the detection of γ 1 adopts the viscometer test, the detection of Δn adopts the Abbe refractometer test, and the detection of Δε adopts the capacitive reactance tester of Hewlett-Packard Company model HP-4284A to measure.

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); γ 1 represents rotational viscosity (mPa·s, 25°C); Δε represents dielectric anisotropy (25°C, 1000Hz).

The performance parameter data of the liquid crystal compounds prepared in Examples 1 to 8 and the liquid crystal compounds of Comparative Examples 1 to 2 are compared and sorted, and the test results are shown in Table 8:

It can be clearly seen from the test results in Table 8 that the liquid crystal compounds provided in Examples 1 to 5 of the present invention have higher optical anisotropy Δn and lower rotational viscosity γ 1 compared with traditional compounds with similar chemical structures. , which can shorten the response time.

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 (10)

A thiophene-containing acetylene liquid crystal compound, wherein, it has the structure shown by the general formula (I):

In the formula, R ₁ and R ₂ each independently represent -H, -Cl, -F, -CN, -OCN, -OCF ₃ , -CF ₃ , -CHF ₂ , -CH ₂ F, -OCHF ₂ , -OCF=CF ₂ , -OCF ₂ CF ₃ , -SCN, -NCS, -SF ₅ , C ₁ -C ₁₅ alkyl, C ₁ -C ₁₅ alkoxy, C ₂ -C ₁₅ alkenyl or C ₂ -C ₁₅ alkenyloxy, wherein one or more of the C ₁ -C ₁₅ alkyl group, C ₁ -C ₁₅ alkoxy group, C ₂ -C ₁₅ alkenyl group or C ₂ -C ₁₅ alkenyloxy group hydrogens can be optionally substituted by fluorine or chlorine, and one or more non-adjacent _-CH2- can be independently of each other by -CH=CH-, -C≡C-, -COO-, -OOC-, -O- or -S- substitution; A ₁ and A ₂ each independently represent a single bond or one of the following groups:

Z ₁ and Z ₂ each independently represent a single bond, -CH ₂ -, -CH ₂ -CH ₂ -, -(CH ₂ ) ₃ -, -(CH ₂ ) ₄ -, -CH=CH-, -C≡ C-, -COO-, -OOC-, -OCH ₂ -, -CH ₂ O-, -CF ₂ O-, -OCF ₂ -, -CF ₂ CH ₂ -, -CH ₂ CF ₂ -, -C ₂ F ₄ -or -CF=CF-; n=0, 1, 2, 3 or 4. The thiophene-containing alkyne-based liquid crystal compound according to claim 1, wherein R ₁ and R ₂ each independently represent -H, -CF ₃ , -OCF ₃ , -CN, -NCS, and C ₁ -C ₇ alkanes or C ₁ -C ₇ alkoxy, and one or more hydrogens in said C ₁ -C ₇ alkyl or C ₁ -C ₇ alkoxy may be optionally substituted by fluorine or chlorine, Substituted by fluorine is preferred. The thiophene-containing alkyne-based liquid crystal compound according to claim 1 or 2, wherein A ₁ and A ₂ each independently represent a single bond or one of the following groups:

The thiophene-containing alkyne-based liquid crystal compound according to any one of claims 1 to 3, wherein Z ₁ and Z ₂ each independently represent a single bond, -CH ₂ -, -CH ₂ -CH ₂ -, -(CH ₂ ) _3- , -( _CH2 ) _4- , -COO-, _-OOC- , _-OCH2- , _-CH2O- , -CF2O- or _-OCF2- . The thiophene-containing alkyne-based liquid crystal compound according to any one of claims 1 to 4, wherein the compound represented by the general formula (I) is selected from one or more of the following structures:

Wherein, the designations of R ₁ , R ₂ and Z ₂ are the same as those described in any one of claims 1-4. The preparation method of the thiophene-containing acetylene liquid crystal compound according to any one of claims 1 to 5, wherein the synthesis route is as follows:

Specifically include the following steps: Compound I-1-01 and compound I-1-02 are reacted under the action of triethylamine and palladium catalysts to obtain target compound I; Wherein, the designations of R ₁ , R ₂ , A ₁ , A ₂ , Z ₁ , and Z ₂ are the same as those described in any one of claims 1-5. A liquid crystal composition comprising the thiophene-containing acetylenic liquid crystal compound according to any one of claims 1 to 5. The liquid crystal composition according to claim 7, wherein the mass percentage of the thiophene-containing acetylenic liquid crystal compound in the liquid crystal composition is 1 to 60%, preferably 3 to 50%, and more preferably 5 to 50%. 25%. An application in the field of liquid crystal display, which contains the thiophene-containing acetylene liquid crystal compound according to any one of claims 1 to 5 or the liquid crystal composition according to claim 7 or 8, wherein, preferably, the liquid crystal display field It is a liquid crystal display device, more preferably, the liquid crystal display device is a TN or STN liquid crystal display. An application in the field of molecular antennas, comprising the thiophene-containing acetylene liquid crystal compound according to any one of claims 1 to 5 or the liquid crystal composition according to claim 7 or 8.