阅读说明：本技术 一种双烯类负性液晶化合物及其制备方法和应用 (Diene negative liquid crystal compound and preparation method and application thereof ) 是由 王艳伟 孙云峰 国新涛 王谦 姜晓辉 崔行浩 尹环 史子谦 丰佩川 于 2020-06-11 设计创作，主要内容包括：本发明涉及一种双烯类负性液晶化合物及其制备方法和应用。所述负性液晶化合物如所示通式Ⅰ的结构。所述负性液晶化合物如所示通式Ⅰ的结构具有双烯结构及极大的负介电各向异性,可提高液晶组合物的陡度、降低粘度、缩短响应时间。含有该液晶化合物的液晶组合物同时具备良好的低温稳定性及互溶性,较强的抗UV能力和高的VHR及电阻率,适用于VA、MVA、PVA、FFS、PSVA、IPS、TFT等显示模式。<Image he="139" wi="700" file="DDA0002534834050000011.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>(The invention relates to a diene negative liquid crystal compound and a preparation method and application thereof. The negative liquid crystal compound has a structure shown as a general formula I. The structure of the negative liquid crystal compound shown as the general formula I has a diene structure and great negative dielectric anisotropy, and can improve the gradient of a liquid crystal composition, reduce the viscosity and shorten the response time. The liquid crystal composition containing the liquid crystal compound has good low-temperature stability and intersolubility, strong UV resistance andhigh VHR and resistivity, and is suitable for display modes such as VA, MVA, PVA, FFS, PSVA, IPS, TFT, etc.)

1. A diene negative liquid crystal compound characterized in that the general formula has the following structure:

wherein R is₁C2-C15 substituted or unsubstituted straight chain or branched chain alkene is selectedRadical, R₂Selecting a substituted or unsubstituted straight chain or branched chain alkyl or alkoxy of C1-C15, wherein the substituent is selected from F, Cl, Br, I or CN;

ring A represents cyclohexyl, phenylene, phenyl, an oxygen-containing hexacyclic group or phenylene containing a substituent, wherein the substituent is selected from F, Cl, Br, I or CN;

Z₁is selected from-CH₂CH₂-、-CF₂O-or-CH₂O-；

L₁Selected from H, CN, CH₃Or F.

2. The negative liquid crystal compound according to claim 1, wherein the negative liquid crystal compound is selected from at least one of the following structural formulae:

3. the negative liquid crystal compound according to claim 1 or 2, wherein R is₁Selected from alkenyl, in particular ethenyl, propenyl or butenyl.

4. The negative liquid crystal compound according to claim 1 or 2, wherein R is₂Is selected from methyl or alkoxy of C1-C7.

5. The negative liquid crystal compound according to claim 1 or 2, wherein the negative liquid crystal compound is selected from at least one of the following structural formulae:

6. a method for preparing a negative liquid crystal compound according to claim 2, wherein said compound i-2 is prepared by the steps of:

(1) compound (I)Reacting to produce the compound

(2) Compound (I)Reacting to produce the compound

(3) The compounds obtained in the step (1) and the step (2) react to generateFurther withReaction to form

7. A method for preparing a negative liquid crystal compound according to claim 2, wherein said compound i-7 is prepared by the steps of:

with a compoundPreparing a compound by taking the raw material through metal lithiation and nucleophilic reactionThen undergoing a wittig reaction and waterPreparation of aldehydes by decomposition reactionsFollowed by reduction and bromination to prepare intermediate compoundsAnd compoundsReacting to obtain the compound

8. A negative liquid crystal composition comprising the liquid crystal compound according to claim 1 or 2.

9. A liquid crystal display comprising the liquid crystal compound according to claim 1 or 2.

10. Use of a liquid crystal display device as claimed in claim 9 in VA, MVA, PVA, FFS, PSVA, IPS and TFT display modes.

Technical Field

The invention relates to a diene negative liquid crystal compound and a preparation method and application thereof, belonging to the technical field of liquid crystal materials.

Background

In order to make the performance of display devices closer to ideal, research into new liquid crystal compounds has been continuously conducted, which makes the performance of liquid crystal compounds and display devices continuously progress. In recent years, many negative materials containing fluorine or cyanogen at lateral positions are applied to liquid crystal mixtures, but research and development in the field of liquid crystal materials are still far from being completed. In order to improve the performance of liquid crystal display elements, attempts are constantly being made to develop new compounds which are capable of optimizing such displays.

The liquid crystal material is a rod-like organic compound which has liquid fluidity and crystal anisotropy at a certain temperature, has the inherent characteristics of optical anisotropy (delta n) and dielectric anisotropy (delta), and is a key photoelectric material for producing display devices. None of the liquid crystalline compounds has so far been able to meet all the requirements. It is generally desirable that a mixture of 2 to 25 monomer compounds, more preferably 3 to 18 compounds, can be used as the liquid crystal phase.

The optical characteristics of the liquid crystal before and after the application of a voltage as a dielectric reversibly change. Liquid crystal displays use a wide variety of electro-optic effects. Special liquid-crystalline media are required for the novel VA displays. For example, liquid crystal media with negative dielectric anisotropy need to have a high VHR after UV exposure. The LC phase used in electro-optic displays needs to meet a number of requirements. Of particular importance are chemical and physical stability to moisture, air, such as thermal stability, resistance to infrared radiation, the visible and ultraviolet regions, and direct or alternating electric fields.

As the display technology advances, the demand for display devices is increasing, and increasing the response speed of liquid crystal display devices is an important way to achieve this demand, and the response speed of liquid crystal displays is mainly limited by the liquid crystal dielectric anisotropy, the thickness of the liquid crystal cell, and the rotational viscosity of the liquid crystal, and therefore, there is a significant demand for liquid crystal media having suitable properties for practical use, such as a wide operating range, suitable optical anisotropy, high dielectric anisotropy and particularly low rotational viscosity according to the display mode.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides a diene negative liquid crystal compound and a preparation method thereof. The compound has a diene structure and great negative dielectric anisotropy, can remarkably improve the gradient of a liquid crystal composition and reduce the viscosity when applied to a negative liquid crystal composition, shortens the response time, and the liquid crystal composition containing the liquid crystal compound has good low-temperature stability and intersolubility, strong UV resistance, high VHR (very high-frequency response) and high resistivity.

The invention provides a diene negative liquid crystal compound, which has the following general formula:

wherein R is₁A substituted or unsubstituted linear or branched alkenyl radical selected from C2 to C15， R₂Selecting a substituted or unsubstituted straight chain or branched chain alkyl or alkoxy of C1-C15, wherein the substituent is selected from F, Cl, Br, I or CN;

ring A represents cyclohexyl, phenylene, phenyl, an oxygen-containing hexacyclic group or phenylene containing a substituent, wherein the substituent is selected from F, Cl, Br, I or CN;

Z₁is selected from-CH₂CH₂-、-CF₂O-or-CH₂O-；

L₁Selected from H, CN, CH₃Or F.

Further, the negative liquid crystal compound is selected from at least one of the following structural formulas:

further, said R₁Selected from alkenyl, in particular ethenyl, propenyl or butenyl.

Further, said R₂Is selected from methyl or alkoxy of C1-C7.

Further, the negative liquid crystal compound is selected from at least one of the following structural formulas:

the invention also provides a preparation method of the negative liquid crystal compound, and the preparation method of the compound I-2 comprises the following steps:

(1) compound (I)Reacting to produce the compound

(2) Compound (I)Reacting to produce the compound

(3) The compounds obtained in the step (1) and the step (2) react to generateFurther withReaction to form

Further, the preparation of the compound I-7 comprises the following steps:

with a compoundPreparing a compound by taking the raw material through metal lithiation and nucleophilic reactionPreparing aldehyde through wittig reaction and hydrolysis reaction Followed by reduction and bromination to prepare intermediate compoundsAnd compoundsReacting to obtain the compound

The invention also provides a negative liquid crystal composition which comprises the liquid crystal compound.

The invention also provides a liquid crystal display comprising the liquid crystal compound.

The invention also provides the application of the liquid crystal display device in VA, MVA, PVA, FFS, PSVA, IPS and TFT display modes.

The liquid crystal compound has the advantages of larger refractive index, equivalent clearing point, larger △, lower rotational viscosity and higher K₃₃/K₁₁It is more suitable for low-voltage and high-gradient VA type liquid crystal display.

Detailed Description

The invention will be illustrated below with reference to specific embodiments. It should be noted that the following examples are illustrative of the present invention, and are not intended to limit the present invention. Other combinations and various modifications within the spirit or scope of the present invention may be made without departing from the spirit or scope of the present invention.