Azo dye compound and application thereof

Abstract

The invention relates to the technical field of azo dye materials, and particularly discloses an azo dye compound and application thereof. The azo dye compound provided by the invention has the maximum absorption wavelength range of 470nm-560nm, and has the characteristics of high dichroic ratio, good solubility, small chromatic aberration under extreme environmental conditions (UV, high temperature, high temperature and high humidity), excellent stability and durability and the like. The solubility of the azo dye compound provided by the invention in a liquid crystal material can reach more than 3wt%, the azo dye compound can be stored in a liquid crystal medium for a long time, when the azo dye compound is applied to a liquid crystal composition, small color difference change can be maintained after the UV is 168 hours, the high temperature is 85 DEG C for 1000 hours and the high temperature is 85 DEG C to the high humidity is 85% for 1000 hours, and the azo dye compound has excellent stability and durability. The azo dye compound disclosed by the invention is simple in synthesis method, can meet industrial production requirements, and is remarkable in optical performance when being applied to a dimming element.

Description

Technical Field

[0001] This invention relates to the field of azo dye materials technology, and in particular to an azo dye compound and its applications. Background Technology

[0002] A liquid crystal dimming element is a device that utilizes the optical properties of liquid crystal materials to achieve dimming functionality. It typically consists of liquid crystal material, electrodes, and an alignment layer. Liquid crystal materials containing dichroic dyes eliminate the need for polarizing plates, enabling the production of dimming elements with high transmittance at low cost, and thus finding wide application in dimming devices. The working principle of a liquid crystal dimming element is to change the orientation of liquid crystal molecules by applying an electric field, thereby altering the light transmittance. When an electric field is applied, the liquid crystal molecules rearrange, allowing light to pass through the element; when the electric field is removed, the liquid crystal molecules return to their original orientation, blocking the light. Liquid crystal dimming elements offer advantages such as fast response speed, wide dimming range, and low power consumption, and are widely used in various display devices, optical components, and smart windows.

[0003] In recent years, dimming elements used in smart windows or smart glass to adjust the degree of external light transmission have attracted much attention in order to improve spatial comfort and convenience. In the automotive industry, car windows can utilize liquid crystal switchable viewing technology to adjust transparency. They can become opaque when privacy is needed and return to clear visibility while driving, ensuring a safe view. In the construction industry, smart windows can switch between transparency and insulation performance based on indoor and outdoor light and temperature conditions, achieving energy efficiency and a comfortable indoor environment. In the aerospace industry, aircraft windows can use this technology to help passengers adjust visibility during flight and also help control cabin light and temperature. In the exhibition industry, in museums and exhibition halls, display cases can use liquid crystal switchable viewing windows to maintain clarity during normal displays while preventing overexposure or protecting exhibits under specific conditions. In the industrial control industry, control panels or observation windows of certain industrial equipment can use this technology to switch viewing states according to operating procedures and safety requirements. In the smart home industry, partitions and wardrobe doors can change the openness and privacy of spaces by switching viewing states. Compared with traditional technologies, smart windows or smart glass have many advantages. First, it offers high flexibility and customizability to meet diverse needs in different scenarios. Second, it excels in privacy protection, for example, it can quickly switch to an opaque state in situations requiring confidentiality. Third, its switching speed is relatively fast, enabling timely response to control signals.

[0004] However, liquid crystal dimming elements still face some challenges. For example, when used in extreme environmental conditions (UV, high temperature, or high temperature and high humidity), smart windows or smart glass may experience color changes or other functional interferences in the liquid crystal layer within the window. Furthermore, their stability and durability after long-term use require further optimization. One feasible solution to these problems is to use dyes with good stability, while also ensuring a high dichroism ratio and good solubility. Therefore, to improve the performance of dyes in liquid crystal dimming elements (especially smart windows or smart glass), it is urgent to develop a dye compound with high solubility, a high dichroism ratio, and good stability and durability under extreme environmental conditions (UV, high temperature, and high temperature and high humidity). Summary of the Invention

[0005] To address the aforementioned problems, this invention provides an azo dye compound and its applications, solving the issues of poor solubility, low dichroism, and poor stability and durability of azo dyes in liquid crystal compositions under extreme environmental conditions (UV, high temperature, and high temperature and high humidity). Liquid crystal compositions containing this azo dye compound can be used to prepare liquid crystal dimming elements.

[0006] To solve the above-mentioned technical problems, the technical solution provided by the present invention is as follows: An azo dye compound, the structural formula of which is shown in Formula I:

[0007] Formula I; In the formula, , , , , , and Represented independently or ; L1 to L7 represent hydrogen atoms, halogen atoms, C1 to C15 alkyl groups, or C1 to C15 alkoxy groups, respectively. R1 to R4 represent, independently, a hydrogen atom, a C1 to C15 alkyl group, a C1 to C15 substituted alkyl group, a C2 to C15 alkyl group containing an ester group, a C3 to C15 alkenyl group, a C3 to C15 alkynyl group, a C2 to C15 alkyl group containing an ether group, or a C2 to C15 alkyl group containing a thioether group. Z1 represents a nitrogen atom, an oxygen atom, or a sulfur atom; when Z1 represents a nitrogen atom, m=1; when Z1 represents an oxygen atom or a sulfur atom, m=0. Z2 represents a nitrogen atom, an oxygen atom, or a sulfur atom; when Z2 represents a nitrogen atom, n=1; when Z2 represents an oxygen atom or a sulfur atom, n=0. x represents 0 or 1, and y represents 0 or 1.

[0008] Compared to existing technologies, the azo dye compound provided by this invention has a maximum absorption wavelength range of 470nm~560nm, high dichroism ratio and good solubility in liquid crystal materials (its solubility can reach more than 3wt%), can be stored in liquid crystal media for a long time, and exhibits small color difference, excellent stability and durability under extreme environmental conditions (UV, high temperature, high temperature and high humidity). When applied to liquid crystal compositions, it can maintain small color difference changes after UV exposure for 168h, high temperature of 85℃ for 1000h, and high temperature of 85℃ and high humidity of 85% for 1000h, demonstrating excellent stability and durability.

[0009] For example, the structural formulas of the azo dye compounds are shown in Formulas I-1 to I-4:

[0010] Formula I-1

[0011] Formula I-2

[0012] Formula I-3

[0013] Formula I-4.

[0014] Preferred, express .

[0015] Preferred, express .

[0016] Preferred, express .

[0017] Preferred, express .

[0018] More preferably, the structural formula of the azo dye compound is shown in Formula I-11, Formula I-21, Formula I-31, Formula I-32 or Formula I-33:

[0019] Formula I-11

[0020] Formula I-21

[0021] Formula I-31

[0022] Formula I-32

[0023] Formula I-33.

[0024] Preferably, L1 to L7 independently represent a hydrogen atom, a halogen atom, a C1 to C5 straight-chain alkyl group, or a C1 to C5 straight-chain alkoxy group.

[0025] Preferably, R1 represents a hydrogen atom, a C1-C10 straight-chain alkyl group, a C4-C15 cycloalkyl group, or a C1-C10 halo-chain straight-chain alkyl group.

[0026] Preferably, R2 represents a hydrogen atom, a C1-C10 straight-chain alkyl group, a C4-C15 cycloalkyl group, a C1-C10 haloalkyl group, or a C3-C10 straight-chain alkyl group containing an ester group.

[0027] Preferably, R3 represents a hydrogen atom, a C1-C10 straight-chain alkyl group, a C4-C15 cycloalkyl group, or a C1-C10 halo-chain straight-chain alkyl group.

[0028] Preferably, R4 represents a hydrogen atom, a C1-C10 straight-chain alkyl group, a C4-C15 cycloalkyl group, a C1-C10 halo-chain alkyl group, or a C3-C10 straight-chain alkyl group containing an ester group.

[0029] More preferably, the C4-C15 cycloalkyl group is containing... , , or Straight-chain alkyl groups.

[0030] More preferably, L1 to L7 independently represent -H, -F, or -CH3, respectively.

[0031] More preferably, R1 represents a hydrogen atom or a C1~C6 straight-chain alkyl group.

[0032] More preferably, R2 represents a C3~C10 straight-chain alkyl group or a C4~C10 straight-chain alkyl group containing -CO-O-.

[0033] More preferably, R3 represents a hydrogen atom or a C1~C6 straight-chain alkyl group.

[0034] More preferably, R4 represents a C3~C10 straight-chain alkyl group or a C4~C10 straight-chain alkyl group containing -CO-O-.

[0035] More preferably, the structural formula of the azo dye compound is shown in Formula I-111, Formula I-211, Formula I-311, Formula I-321 or Formula I-331:

[0036] Formula I-111

[0037] Formula I-211

[0038] Formula I-311

[0039] Formula I-321

[0040] Formula I-331; In the formula, L3 represents -H, -F, or -CH3; L4 represents -H or -F; L 51 Indicates -H or -F, L 52 Indicates -H or -F, and L 51 and L 52 Not simultaneously represent -F; L6 represents -H, -F, or -CH3.

[0041] More preferably, the azo dye compound includes at least one of the compounds with the structure shown in Formula I-111-1 to Formula I-111-7, Formula I-211-1 to Formula I-211-4, Formula I-311-1, Formula I-321-1, Formula I-321-2, Formula I-331-1, or Formula I-331-2:

[0042] Formula I-111-1

[0043] Formula I-111-2

[0044] Formula I-111-3

[0045] Formula I-111-4

[0046] Formula I-111-5

[0047] Formula I-111-6

[0048] Formula I-111-7

[0049] Formula I-211-1

[0050] Formula I-211-2

[0051] Formula I-211-3

[0052] Formula I-211-4

[0053] Formula I-311-1

[0054] Formula I-321-1

[0055] Formula I-321-2

[0056] Formula I-331-1

[0057] Formula I-331-2.

[0058] Secondly, the present invention provides a method for synthesizing the azo dye compound having the structural formula of Formula I.

[0059] 1. When the azo dye compound is as shown in Formula I-1, the reaction equation is shown in Formula 1:

[0060] Formula 1; In the formula, , , , and Represented independently or ; L2 to L6 represent hydrogen atoms, halogen atoms, C1 to C15 alkyl groups, or C1 to C15 alkoxy groups, respectively. R1 to R4 represent, independently, a hydrogen atom, a C1 to C15 alkyl group, a C1 to C15 substituted alkyl group, a C2 to C15 alkyl group containing an ester group, a C3 to C15 alkenyl group, a C3 to C15 alkynyl group, a C2 to C15 alkyl group containing an ether group, or a C2 to C15 alkyl group containing a thioether group. Z1 represents a nitrogen atom, an oxygen atom, or a sulfur atom; when Z1 represents a nitrogen atom, m=1; when Z1 represents an oxygen atom or a sulfur atom, m=0. Z2 represents a nitrogen atom, an oxygen atom, or a sulfur atom; when Z2 represents a nitrogen atom, n=1; when Z2 represents an oxygen atom or a sulfur atom, n=0. x represents 0 or 1, and y represents 0 or 1.

[0061] 2. When the azo dye compound is as shown in Formula I-2, the reaction equation is shown in Formula 2:

[0062] Formula 2; In the formula, , , , , and Represented independently or ; L2 to L7 represent hydrogen atoms, halogen atoms, C1 to C15 alkyl groups, or C1 to C15 alkoxy groups, respectively. R1 to R4 represent, independently, a hydrogen atom, a C1 to C15 alkyl group, a C1 to C15 substituted alkyl group, a C2 to C15 alkyl group containing an ester group, a C3 to C15 alkenyl group, a C3 to C15 alkynyl group, a C2 to C15 alkyl group containing an ether group, or a C2 to C15 alkyl group containing a thioether group. Z1 represents a nitrogen atom, an oxygen atom, or a sulfur atom; when Z1 represents a nitrogen atom, m=1; when Z1 represents an oxygen atom or a sulfur atom, m=0. Z2 represents a nitrogen atom, an oxygen atom, or a sulfur atom; when Z2 represents a nitrogen atom, n=1; when Z2 represents an oxygen atom or a sulfur atom, n=0. x represents 0 or 1, and y represents 0 or 1.

[0063] 3. When the azo dye compound is as shown in Formula I-3, the reaction equation is shown in Formula 3:

[0064] Formula 3; In the formula, , , , , and Represented independently or ; L1 to L6 represent hydrogen atoms, halogen atoms, C1 to C15 alkyl groups, or C1 to C15 alkoxy groups, respectively. R1 to R4 represent, independently, a hydrogen atom, a C1 to C15 alkyl group, a C1 to C15 substituted alkyl group, a C2 to C15 alkyl group containing an ester group, a C3 to C15 alkenyl group, a C3 to C15 alkynyl group, a C2 to C15 alkyl group containing an ether group, or a C2 to C15 alkyl group containing a thioether group. Z1 represents a nitrogen atom, an oxygen atom, or a sulfur atom; when Z1 represents a nitrogen atom, m=1; when Z1 represents an oxygen atom or a sulfur atom, m=0. Z2 represents a nitrogen atom, an oxygen atom, or a sulfur atom; when Z2 represents a nitrogen atom, n=1; when Z2 represents an oxygen atom or a sulfur atom, n=0. x represents 0 or 1, and y represents 0 or 1.

[0065] 4. When the azo dye compound is as shown in Formula I-4, the reaction equation is shown in Formula 4:

[0066] Equation 4; In the formula, , , , , , and Represented independently or ; L1 to L7 represent hydrogen atoms, halogen atoms, C1 to C15 alkyl groups, or C1 to C15 alkoxy groups, respectively. R1 to R4 represent, independently, a hydrogen atom, a C1 to C15 alkyl group, a C1 to C15 substituted alkyl group, a C2 to C15 alkyl group containing an ester group, a C3 to C15 alkenyl group, a C3 to C15 alkynyl group, a C2 to C15 alkyl group containing an ether group, or a C2 to C15 alkyl group containing a thioether group. Z1 represents a nitrogen atom, an oxygen atom, or a sulfur atom; when Z1 represents a nitrogen atom, m=1; when Z1 represents an oxygen atom or a sulfur atom, m=0. Z2 represents a nitrogen atom, an oxygen atom, or a sulfur atom; when Z2 represents a nitrogen atom, n=1; when Z2 represents an oxygen atom or a sulfur atom, n=0. x represents 0 or 1, and y represents 0 or 1.

[0067] It should be noted that, for similar The preparation method of the phenyl derivatives or naphthyl derivatives shown is not limited in this invention, and conventional preparation methods in the art can be used.

[0068] The method for synthesizing azo dye compounds provided by this invention is simple, the raw materials are readily available, the reaction conditions are mild, the post-processing is convenient, and the yield is high, which can meet the needs of industrial production.

[0069] Thirdly, the present invention provides a liquid crystal composition comprising the aforementioned azo dye compound.

[0070] Preferably, the liquid crystal composition further comprises parent liquid crystal.

[0071] More preferably, the liquid crystal composition further comprises an ultraviolet absorber and a sterically hindered phenolic antioxidant.

[0072] More preferably, the mass ratio of the azo dye compound to the parent liquid crystal is 0.05:100 to 5:100.

[0073] More preferably, the mass ratio of the ultraviolet absorber to the parent liquid crystal is 0.1:100 to 0.7:100.

[0074] More preferably, the mass ratio of the sterically hindered phenolic antioxidant to the parent liquid crystal is 0.01:100 to 0.07:100.

[0075] Fourthly, the present invention provides an application of the aforementioned azo dye compound in the preparation of dimming elements.

[0076] Fifthly, the present invention provides an application of the liquid crystal composition described above in the preparation of a dimming element.

[0077] The liquid crystal composition containing azo dye compounds provided by this invention exhibits excellent solubility and contrast performance in different parent liquid crystals, good durability and stability under extreme environmental conditions, and can obtain favorable and stable optical performance. When applied to products such as dimming elements, the optical performance is significantly improved. Attached Figure Description

[0078] Figure 1 This is a transmittance curve of azo dye compounds D1 and I-111-4 at different wavelengths (0V and 10V) in the parent liquid crystal 1. Figure 2 This refers to the dichroism ratio of azo dye compounds D1 and I-111-4 at different wavelengths in the parent liquid crystal 1 in this invention. Detailed Implementation

[0079] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0080] Unless otherwise specified, all percentages in this instruction manual refer to mass percentages. The specific meanings and test conditions for other symbols are as follows: Cp represents the liquid crystal clearing point (°C), measured by DSC quantitative method; Δn represents optical anisotropy, no is the refractive index of ordinary light, ne is the refractive index of extraordinary light, and the test conditions are 25±2℃, 589nm, and Abbe refractometer test. Δε represents dielectric anisotropy, Δε=ε∥-ε⊥, where ε∥ is the dielectric constant parallel to the molecular axis and ε⊥ is the dielectric constant perpendicular to the molecular axis. The test conditions are 25±0.5℃, 20-micron parallel cell, INSTEC:ALCT-IR1 test. LTS stands for Low Temperature Stability (Nematic Phase), which is determined in the test unit.

[0081] In this embodiment of the invention, the structure of the ultraviolet absorber used is shown in Formula II, and the structure of the sterically hindered phenolic antioxidant used is shown in Formula III:

[0082] Formula II

[0083] Formula III.

[0084] To better illustrate the present invention, further examples are provided below.

[0085] Example 1 This embodiment provides an azo dye compound I-111-4, the synthetic route of which is shown in Formula 5, and the synthetic method includes the following steps: S1, 25 g (0.233 mol) N-toluidine, 58 g (0.354 mol) bromohexane, 97 g (0.7 mol) potassium carbonate and 200 mL DMF were added to a 500 mL three-necked flask. After purging with nitrogen three times, the temperature was raised to 110 °C and the reaction was carried out for 24 h. Then, the temperature was lowered to room temperature, the reaction solution was poured into 500 mL of ice water, extracted with ethyl acetate, dried and concentrated to obtain 25 g (0.131 mol) of yellow oily intermediate 1 (the specific structure is shown in Formula 5), ​​with a yield of 56.0%.

[0086] S2, add 200mL of water, 25mL of 3N hydrochloric acid and 25g (0.132mol) of o-fluoro-p-bromoaniline to a 500mL three-necked flask, cool the system to 0℃, add 9.3g (0.135mol) of sodium nitrite, keep warm and stir for 1h to obtain solution A.

[0087] Add 100 mL of ethanol, 50 mL of water and 25 g (0.131 mol) of intermediate 1 to a 1 L three-necked flask. Cool the system to 0 °C and stir for 0.5 h to obtain solution B.

[0088] The temperature was controlled at 0℃. Solution A was added to solution B within 20 min, and the mixture was kept at this temperature and stirred for 1 h. Then, 500 mL of water and 300 mL of ethyl acetate were added to the system. After stirring, the mixture was separated. The aqueous phase was extracted with ethyl acetate, and the organic phase was dried, concentrated, and purified by silica gel column chromatography (the mass ratio of petroleum ether to ethyl acetate was 15:1) to obtain 13 g (0.033 mol) of intermediate 2 (the specific structure is shown in Formula 5), ​​with a yield of 25.4%.

[0089] S3. Add 200 mL of water, 25 mL of 3N hydrochloric acid and 25 g (0.132 mol) of o-fluoro-p-bromoaniline to a 500 mL three-necked flask. Cool the system to 0 °C, add 9.3 g (0.135 mol) of sodium nitrite, and stir for 1 h to obtain solution C.

[0090] Add 100 mL of ethanol, 50 mL of water and 14.1 g (0.132 mol) of m-toluidine to a 1 L three-necked flask. Cool the system to 0 °C and stir for 0.5 h to obtain solution D.

[0091] The temperature was controlled at 0℃. Solution C was added to solution D over 20 min and kept at this temperature with stirring for 1 h. Then, 500 mL of water and 300 mL of ethyl acetate were added to the system. After stirring, the mixture was separated. The aqueous phase was extracted with ethyl acetate, and the organic phase was dried, concentrated, and purified by silica gel column chromatography (the mass ratio of petroleum ether to ethyl acetate was 15:1) to obtain 16 g (0.052 mol) of intermediate 3 (the specific structure is shown in Formula 5), ​​with a yield of 39.5%.

[0092] S4. Add 100 mL of water, 15 mL of 3N hydrochloric acid and 16 g (0.052 mol) of intermediate 3 to a 500 mL three-necked flask. Cool the system to 0 °C, add 4.02 g (0.058 mol) of sodium nitrite, and stir for 1 h to obtain solution E.

[0093] Add 80 mL of ethanol, 50 mL of water and 10.6 g (0.052 mol) of N,N-dibutylaniline to a 1 L three-necked flask. Cool the system to 0 °C and stir for 0.5 h to obtain solution F.

[0094] The temperature was controlled at 0℃. Solution E was added to solution F within 20 min, and the mixture was kept at this temperature and stirred for 1 h. Then, 500 mL of water and 300 mL of ethyl acetate were added to the system. After stirring, the mixture was separated. The aqueous phase was extracted with ethyl acetate, and the organic phase was dried, concentrated, and purified by silica gel column chromatography (the mass ratio of petroleum ether to ethyl acetate was 15:1) to obtain 5 g (0.010 mol) of intermediate 4 (the specific structure is shown in Formula 5), ​​with a yield of 18.4%.

[0095] S5, 5 g (0.010 mol) of intermediate 4, 2.8 g (0.011 mol) of pinacol diboryl ester, 1.8 g (0.013 mol) of potassium carbonate, 0.03 g (0.026 mmol) of tetraphenylphosphine palladium and 30 mL of toluene were added to a 250 mL three-necked flask and heated under nitrogen protection and refluxed for 3 h. After the reaction was confirmed to be complete by TLC, the resulting reaction solution was cooled to 30 °C, 3.4 g (0.009 mol) of intermediate 2 was added, and the mixture was heated under reflux for 3 h and cooled to room temperature. 100 mL of water was added to the resulting reaction solution, the mixture was separated, and the organic phase was passed through a silica gel column and concentrated to obtain 5 g of red solid. After coating the sample with silica gel and mixing it, the sample was passed through a silica gel column (the mass ratio of petroleum ether to ethyl acetate was 20:1) to obtain 2.1 g (0.003 mol) of azo dye compound I-111-4, MS (m / z) (M+): 756.44, yield 32.0%.

[0096]

[0097] Formula 5.

[0098] Example 2 This embodiment provides an azo dye compound I-111-6, synthesized using a method similar to that of Example 1, except that in S1, bromohexane is replaced with ethyl bromopentanoate, and in S4, N,N-dibutylaniline is replaced with ethyl 5-(methylphenylamino)-pentanoate. The remaining steps are the same as in Example 1 and will not be repeated. A total of 2.6 g of azo dye compound I-111-6 was obtained, with MS (m / z) (M+): 830.41, and a yield of 25.1%.

[0099]

[0100] Formula I-111-6.

[0101] Example 3 This embodiment provides an azo dye compound I-111-7, synthesized using a method similar to that of Example 1, except that: in S2, intermediate 1 is replaced with phenylpentyl ether (step S1 is omitted); in S3, o-fluoro-p-bromoaniline is replaced with p-bromoaniline; and in S4, N,N-dibutylaniline is replaced with phenylhexyl ether. The remaining steps are the same as in Example 1 and will not be repeated. A total of 3.2 g of azo dye compound I-111-7 was obtained, with MS (m / z) (M+): 684.36, and a yield of 35.5%.

[0102]

[0103] Formula I-111-7.

[0104] Example 4 This embodiment provides an azo dye compound I-211-4, the synthetic route of which is shown in Formula 6, and the synthetic method includes the following steps: S1~S2 are the same as S3~S4 in Example 1, and will not be described again.

[0105] S3, 5 g (0.010 mol) of intermediate 4, 1.4 g (0.006 mol) of pinacol diboryl ester, 1.8 g (0.013 mol) of potassium carbonate, 0.03 g (0.026 mmol) of tetraphenylphosphine palladium and 30 mL of toluene were added to a 250 mL three-necked flask and heated under nitrogen protection and refluxed for 3 h. After cooling to room temperature, 100 mL of water was added to the resulting reaction solution, the mixture was separated, and the organic phase was passed through a silica gel column and concentrated to give 4 g of red solid. After coating the sample with silica gel and mixing it, the sample was passed through a silica gel column (the mass ratio of petroleum ether to ethyl acetate was 20:1) to give 1.8 g (0.002 mol) of azo dye compound I-211-4, MS (m / z) (M+): 888.51, yield 21.2%.

[0106]

[0107] Formula 6.

[0108] Example 5 This embodiment provides an azo dye compound I-331-1, the synthetic route of which is shown in Formula 7, and the synthetic method includes the following steps: S1. Add 200 mL of water, 25 mL of 3N hydrochloric acid and 50 g (0.291 mol) of p-bromoaniline to a 500 mL three-necked flask. Cool the system to 0 °C, add 19.6 g (0.284 mol) of sodium nitrite, and stir for 1 h to obtain solution A.

[0109] Add 100 mL of ethanol, 50 mL of water and 41.7 g (0.291 mol) of 1-naphthylamine to a 1 L three-necked flask. Cool the system to 0 °C and stir for 0.5 h to obtain solution B.

[0110] The temperature was controlled at 0℃. Solution A was added to solution B within 20 min, and the mixture was kept at this temperature and stirred for 1 h. Then, 500 mL of water and 300 mL of ethyl acetate were added to the system. After stirring, the mixture was separated. The aqueous phase was extracted with ethyl acetate, and the organic phase was dried, concentrated, and purified by silica gel column chromatography (the mass ratio of petroleum ether to ethyl acetate was 15:1) to obtain 62 g (0.190 mol) of intermediate 1 (the specific structure is shown in Formula 7), with a yield of 65.4%.

[0111] S2, add 200mL of water, 25mL of 3N hydrochloric acid and 62g (0.190mol) of intermediate 1 to a 500mL three-necked flask, cool the system to 0℃, add 12.3g (0.178mol) of sodium nitrite, keep warm and stir for 1h to obtain solution C.

[0112] Add 100 mL of ethanol, 50 mL of water and 22 g (0.154 mol) of 1-naphthylamine to a 1 L three-necked flask. Cool the system to 0 °C and stir for 0.5 h to obtain solution D.

[0113] The temperature was controlled at 0℃. Solution C was added to solution D over 20 min and stirred for 1 h. Then, 500 mL of water and 300 mL of ethyl acetate were added to the system. After stirring, the mixture was separated. The aqueous phase was extracted with ethyl acetate, and the organic phase was dried, concentrated, and purified by silica gel column chromatography (the mass ratio of petroleum ether to ethyl acetate was 15:1) to obtain 31 g (0.065 mol) of intermediate 2 (the specific structure is shown in Formula 7), with a yield of 34.0%.

[0114] S3. Add 100 mL of water, 25 mL of 3N hydrochloric acid and 31 g (0.065 mol) of intermediate 2 to a 500 mL three-necked flask. Cool the system to 0 °C, add 4.3 g (0.062 mol) of sodium nitrite, and stir for 1 h to obtain solution E.

[0115] Add 100 mL of ethanol, 50 mL of water and 13 g (0.063 mol) of N-(1-ethylpentyl)phenylpropanol to a 1 L three-necked flask. Cool the system to 0 °C and stir for 0.5 h to obtain solution F.

[0116] The temperature was controlled at 0℃. Solution E was added to solution F within 20 min, and the mixture was kept at this temperature and stirred for 1 h. Then, 500 mL of water and 300 mL of ethyl acetate were added to the system. After stirring, the mixture was separated. The aqueous phase was extracted with ethyl acetate, and the organic phase was dried, concentrated, and purified by silica gel column chromatography (the mass ratio of petroleum ether to ethyl acetate was 15:1) to obtain 10 g (0.014 mol) of intermediate 3 (the specific structure is shown in Formula 7), with a yield of 22.2%.

[0117] S4, 25 g (0.233 mol) N-toluidine, 58 g (0.351 mol) bromohexane, 97 g (0.702 mol) potassium carbonate and 200 mL DMF were added to a 500 mL three-necked flask. After purging with nitrogen three times, the temperature was raised to 110 °C and the reaction was carried out for 24 h. Then the temperature was lowered to room temperature, the reaction solution was poured into 500 mL of ice water, extracted with ethyl acetate, dried and concentrated to obtain yellow oily intermediate 4 (the specific structure is shown in Formula 7).

[0118] S5. Add 200 mL of water, 25 mL of 3N hydrochloric acid and 25 g (0.132 mol) of o-fluoro-p-bromoaniline to a 500 mL three-necked flask. Cool the system to 0 °C, add 9.3 g (0.135 mol) of sodium nitrite, and stir for 1 h to obtain solution A.

[0119] Add 100 mL of ethanol, 50 mL of water and 25 g (0.131 mol) of intermediate 4 to a 1 L three-necked flask. Cool the system to 0 °C and stir for 0.5 h to obtain solution B.

[0120] At 0℃, solution A was added to solution B within 20 min and kept warm and stirred for 1 h. Then, 500 mL of water and 300 mL of ethyl acetate were added to the system, stirred and separated. The aqueous phase was extracted with ethyl acetate, and the organic phase was dried, concentrated and purified by silica gel column chromatography (the mass ratio of petroleum ether to ethyl acetate was 15:1) to obtain intermediate 5 (the specific structure is shown in Formula 7).

[0121] S6, 10 g (0.014 mol) of intermediate 3, 2.8 g (0.011 mol) of pinacol diboryl ester, 4 g (0.029 mol) of potassium carbonate, 0.03 g (0.026 mmol) of tetraphenylphosphine palladium and 30 mL of toluene were added to a 250 mL three-necked flask and heated under nitrogen protection and refluxed for 3 h. After the reaction was confirmed to be complete by TLC, the resulting reaction solution was cooled to 30 °C, 5.5 g (0.014 mol) of intermediate 5 was added, and the mixture was heated under reflux for 3 h and cooled to room temperature. 100 mL of water was added to the resulting reaction solution, the mixture was separated, and the organic phase was passed through a silica gel column and concentrated to obtain 4 g of red solid. After coating the sample with silica gel and mixing it, the sample was passed through a silica gel column (the mass ratio of petroleum ether to ethyl acetate was 20:1) to obtain 1.7 g (0.002 mol) of azo dye compound I-331-1, MS (m / z) (M+): 928.51, yield 15.7%.

[0122]

[0123] Formula 7.

[0124] Example 6 This embodiment provides an azo dye compound I-331-2, synthesized using a method similar to that of Example 5, except that intermediate 4 is replaced with phenylbutyl ether in step S5 (step S4 is omitted). The remaining steps are the same as in Example 5 and will not be repeated. A final yield of 1.2 g of azo dye compound I-331-2 was obtained, with MS (m / z) (M+): 887.44, and a yield of 12.3%.

[0125]

[0126] Formula I-331-2.

[0127] Comparative Example 1 This comparative example provides a known azo dye compound D1, whose structural formula is shown below:

[0128] D1.

[0129] Comparative Example 2 This comparative example provides a known azo dye compound D2, whose structural formula is shown below:

[0130] D2.

[0131] Comparative Example 3 This comparative example provides a known azo dye compound D3, whose structural formula is shown below:

[0132] D3.

[0133] Application examples To test the performance of the azo dye compounds provided by this invention in different parent liquid crystals, the present invention provides the following applications.

[0134] The corresponding codes for ring structures, terminal groups, and linking groups are shown in Tables 1 and 2.

[0135] Table 1. Corresponding codes for ring structures

[0136] Table 2. Correspondence codes between terminal groups and linking groups

[0137] For example: Its code is CC-Cp-V1; Its code is PGP-Cpr1-2; Its code is CPY-2-O2; Its code is CCY-3-O2; Its code is COY-3-O2; Its code is CCOY-3-O2; Its code is Sb-CpO-O4; Its code is Sc-CpO-O4; Its code is CCU-3-F; Its code is PGU-3-F; Its code is CCPU-3-F; Its code is CPGU-3-OT; Its code is DGUQU-4-F; Its code is PGUQU-3-F; Its code is PPGU-Cp-F.

[0138] The composition and physical properties of the parent liquid crystals 1 to 4 are shown in Tables 3 to 6.

[0139] Table 3. Parent Liquid Crystal 1 Serial Number Components mass content % 1 PZG-2-CN 1 2 PZG-3-CN 10 3 CCPU-3-F 3 4 PZU-2-CN 5 5 PZU-3-CN 4 6 CU-3-CN 7 7 CC-3-V 5 8 CCZPC-3-2 14 9 CCZPC-3-3 10 10 CDU-2-F 2 11 CDU-3-F 6 12 CDU-5-F 6 13 CCPU-2-F 9 14 CCGU-3-F 2 15 PGUQU-3-F 5 16 PGUQU-4-F 5 17 PGUQU-5-F 6 18 UV absorber UV-P 0.3 19 hindered phenolic antioxidants 0.03 In the table, the mass content of components 1-17 is 100%. The mass content of UV absorber UV-P represents its proportion to the sum of the masses of components 1-17, and the mass content of sterically hindered phenolic antioxidants represents its proportion to the sum of the masses of components 1-17. The amount of azo dye compound added subsequently is also calculated based on the sum of the masses of components 1-17.

[0140] Table 4. Parent Liquid Crystal 2 Serial Number Components mass content % 1 CC[+N]-3-5 10 2 CPY-3-O2 5 3 CCOY-3-O2 20 4 CCOY-3-O2 11 5 CCY-2-O2 8 6 CCY-4-O2 3 7 CPY-2-O2 10 8 CY-V-O2 11 9 YZY-2O-O2 10 10 PYQY-2-3 3 11 PTY-3-O2 9 12 UV absorber UV-P 0.3 13 hindered phenolic antioxidants 0.03 In the table, the mass content of components 1-11 is 100%. The mass content of UV absorber UV-P represents its proportion to the sum of the masses of components 1-11, and the mass content of sterically hindered phenolic antioxidants represents its proportion to the sum of the masses of components 1-11. The amount of azo dye compound added subsequently is also calculated based on the sum of the masses of components 1-11.

[0141] Table 5. Mother Liquid Crystal 3 Serial Number Components mass content % 1 CCOY-3-O2 30 2 CCP-V-1 8 3 CC-3-V 16.5 4 CY-3-O2 7.5 5 CCY-3-O2 5 6 CCY-2-O2 4 7 CPY-2-O2 10 8 CY-V-O2 5 9 YZY-2O-O2 10 10 PYQY-2-3 2 11 PTY-3-O2 2 12 UV absorber UV-P 0.3 13 hindered phenolic antioxidants 0.03 In the table, the mass content of components 1-11 is 100%. The mass content of UV absorber UV-P represents its proportion to the sum of the masses of components 1-11, and the mass content of sterically hindered phenolic antioxidants represents its proportion to the sum of the masses of components 1-11. The amount of azo dye compound added subsequently is also calculated based on the sum of the masses of components 1-11.

[0142] Table 6. Mother Liquid Crystal 4 Serial Number Components mass content % 1 CCOY-3-O2 8 2 CCOY-5-O2 12 3 CCP-V-1 24.5 4 CC-3-V 6.5 5 CCY-3-O2 10 6 COY-3-O2 5 7 CCOY-2-O2 6 8 CLY-3-O2 10 9 CCOY-2-O4 5 10 CCOY-3-O4 7 11 CCOY-4-O4 6 12 UV absorber UV-P 0.3 13 hindered phenolic antioxidants 0.03 In the table, the mass content of components 1-11 is 100%. The mass content of UV absorber UV-P represents its proportion to the sum of the masses of components 1-11, and the mass content of sterically hindered phenolic antioxidants represents its proportion to the sum of the masses of components 1-11. The amount of azo dye compound added subsequently is also calculated based on the sum of the masses of components 1-11.

[0143] Dichroic contrast ratio test To more closely approximate the actual working conditions of the dye, 0.5% (the mass ratio of I-111-4 to the parent liquid crystal 1) of azo dye compound I-111-4 was added to the parent liquid crystal 1 as a test sample, and 0.5% of azo dye compound D1 was added to the parent liquid crystal 1 as a control sample. The mixture was heated and stirred at 120℃ for 1 hour, then spotted using a TN-7.0 test box and sent for DMS testing. Transmittance spectra from 400nm to 800nm ​​were measured at 0V and 10V, obtaining the transmittance at 0V and 10V for each wavelength. The results are as follows: Figure 1 As shown. By Figure 1 It can be seen that the maximum absorption wavelengths of azo dye compounds I-111-4 and D1 are 500nm~510nm, and the absorption of I-111-4 at 0V is significantly lower than that of D1. Based on the formula: dichroic contrast at each wavelength = transmittance at 10V / transmittance at 0V, ... Figure 2 It can be seen that, around a wavelength of 500 nm, the dichroic ratio of azo dye compound I-111-4 is 10.5, while that of azo dye compound D1 is 3.1. The dichroic ratio of I-111-4 is significantly higher than that of D1, thus making it more suitable for use in dimming elements and other applications.

[0144] Similarly, the dichroism ratios of the azo dye compound provided by this invention and the comparative azo dye compound were tested in the parent liquid crystals 1-4, and the specific data are shown in Table 7. As can be seen from Table 7, the dichroism ratios of the azo dye compound containing the structure shown in Formula I in the parent liquid crystal are significantly better than those of the control samples D1, D2, and D3. This indicates that, compared to the prior art, the liquid crystal composition containing the azo dye compound provided by this invention has a significant improvement in contrast in the parent liquid crystal.

[0145] Table 7. Dichroism ratio data of the azo dye compounds in different parent liquid crystals for the examples and comparative examples. azo dye compounds Mother liquid crystal 1 Mother LCD 2 Mother LCD 3 Mother LCD 4 D1 3.1 3.1 3.2 3.2 D2 3.7 3.7 3.4 3.6 D3 3.2 3.5 3.4 3.5 I-111-1 8.5 9.5 9.4 8.7 I-111-2 9.8 8.4 9.5 8.3 I-111-4 10.5 9.7 9.6 9.7 I-111-5 9.2 8.7 9.3 9.7 I-111-6 10.5 10.5 9.7 9.7 I-211-1 9.5 10.1 10.5 9.7 I-211-2 9.1 9.7 9.5 8.7 I-211-4 8.7 8.6 8.6 8.7 I-311-1 8.6 8.2 8.7 9.7 I-321-2 9.6 9.7 9.3 9.4 I-331-2 9.8 9.5 9.4 9.1 Solubility test The azo dye compound provided by this invention and the comparative azo dye compound were added to different parent liquid crystals at different concentrations (0.5wt%~5wt%), mixed and stirred evenly in glass bottles, and stored at -20℃. The presence of crystal precipitation was observed daily, and the results are shown in Tables 8-11. As can be seen from Tables 8-11, the low-temperature solubility of the azo dye compound provided by this invention in liquid crystal materials is significantly better than that of the comparative azo dye compound.

[0146] Table 8 Solubility data in parent liquid crystal 1 Concentration wt% 0.5 0.8 1 1.5 2 2.5 3 3.5 4 4.5 5 D1 ≥10d ≥10d ≥10d ≥10d ＜9d ＜8d ＜7d ＜6d ＜3d ＜2d ＜1d D2 ≥10d ≥10d ≥10d ＜9d ＜9d ＜8d ＜7d ＜6d ＜2d ＜1d ＜1d D3 ≥10d ≥10d ≥10d ＜10d ＜9d ＜8d ＜7d ＜6d ＜2d ＜1d ＜1d I-111-1 ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ＜8d ＜6d I-111-2 ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ＜9d ＜8d ＜6d I-111-4 ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ＜8d ＜6d I-111-5 ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ＜9d ＜8d ＜6d I-111-6 ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ＜10d ＜9d ＜8d I-211-1 ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ＜8d ＜6d I-211-2 ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ＜9d ＜8d ＜6d I-211-4 ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d I-311-1 ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ＜8d ＜6d I-321-2 ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ＜9d ＜8d ＜6d I-331-2 ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ＜9d ＜8d ＜6d Table 9 Solubility data in parent liquid crystal 2 Concentration wt% 0.5 0.8 1 1.5 2 2.5 3 3.5 4 4.5 5 D1 ≥10d ≥10d ≥10d ＜10d ＜9d ＜8d ＜7d ＜6d ＜3d ＜2d ＜1d D2 ≥10d ≥10d ≥10d ＜9d ＜9d ＜8d ＜7d ＜6d ＜2d ＜1d ＜1d D3 ≥10d ≥10d ＜10d ＜10d ＜9d ＜8d ＜7d ＜6d ＜2d ＜1d ＜1d I-111-1 ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ＜10d ＜8d ＜6d I-111-2 ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥9d ＜8d ＜6d I-111-4 ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ＜8d ＜6d I-111-5 ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ＜9d ＜8d ＜6d I-111-6 ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ＜9d ＜8d I-211-1 ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ＜8d ＜6d I-211-2 ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ＜9d ＜8d ＜6d I-211-4 ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ＜10d ＜10d I-311-1 ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ＜8d ＜6d I-321-2 ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥9d ＜8d ＜6d I-331-2 ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ＜9d ＜8d ＜6d Table 10 Solubility data in parent liquid crystal 3 Concentration wt% 0.5 0.8 1 1.5 2 2.5 3 3.5 4 4.5 5 D1 ≥10d ≥10d ≥10d ≥10d ＜9d ＜8d ＜7d ＜6d ＜3d ＜2d ＜1d D2 ≥10d ≥10d ≥10d ＜9d ＜9d ＜8d ＜7d ＜6d ＜2d ＜1d ＜1d D3 ≥10d ≥10d ≥10d ≥10d ＜9d ＜8d ＜7d ＜6d ＜2d ＜1d ＜1d I-111-1 ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ＜8d ＜6d I-111-2 ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥9d ≥8d ＜6d I-111-4 ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ＜8d ＜6d I-111-5 ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ＜9d ＜8d ＜6d I-111-6 ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ＜10d ＜10d ＜9d ＜8d I-211-1 ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ＜8d ＜6d I-211-2 ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥9d ＜8d ＜6d I-211-4 ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ＜10d ＜10d ＜10d ＜10d I-311-1 ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ＜8d ＜6d I-321-2 ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ＜9d ＜8d ＜6d I-331-2 ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ＜10d ＜9d ＜8d ＜6d Table 11 Solubility data in parent liquid crystal 4 Concentration wt% 0.5 0.8 1 1.5 2 2.5 3 3.5 4 4.5 5 D1 ≥10d ≥10d ＜10d ＜10d ＜9d ＜8d ＜7d ＜6d ＜3d ＜2d ＜1d D2 ≥10d ≥10d ≥10d ＜9d ＜9d ＜8d ＜7d ＜6d ＜2d ＜1d ＜1d D3 ≥10d ≥10d ≥10d ≥10d ＜9d ＜8d ＜7d ＜6d ＜2d ＜1d ＜1d I-111-1 ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ＜10d ＜10d ＜8d ＜6d I-111-2 ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ＜9d ＜8d ＜6d I-111-4 ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ＜8d ＜6d I-111-5 ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ＜10d ＜9d ＜8d ＜6d I-111-6 ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ＜10d ＜10d ＜9d ＜8d I-211-1 ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ＜10d ＜8d ＜6d I-211-2 ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ＜9d ＜8d ＜6d I-211-4 ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ＜10d ＜10d ＜10d ＜10d I-311-1 ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ＜10d ＜8d ＜6d I-321-2 ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ＜10d ＜9d ＜8d ＜6d I-331-2 ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ≥10d ＜10d ＜9d ＜8d ＜6d Color difference test under extreme conditions The extreme conditions in this experiment were UV light treatment for 168 hours, high temperature treatment at 85℃ for 1000 hours, and high temperature and high humidity treatment at 85℃ and 85% (high temperature and high humidity) for 1000 hours. The UV conditions included a wavelength of 365nm and an LED light intensity of 50mw / cm². 2 The tests were conducted at high temperature (85℃) and high temperature (85℃ - 85% humidity) in constant temperature and constant temperature and humidity chambers, respectively. The spectra were measured using a DMS-501 (AUTRONIC MELCHERS, Germany) instrument to determine the L*, a*, and b* values ​​of the sample colors. The color difference ΔE* was calculated in the Lab color space using the formula: ΔE*=[(ΔL*)] 2 +(Δa*) 2 +(Δb*) 2 ] 0.5 .

[0147] In the above formula, ΔL* represents the difference in brightness, ΔL* = L* 最终 -L* 初始 Δa* represents the difference between redness and greenness, Δa* = a* 最终 -a* 初始 Δb* represents the difference between yellowness and blueness, Δb* = b* 最终 -b* 初始 The L*, a*, and b* values ​​of the sample color are determined by the transmission curves of each spectrum (based on the CIE standard colorimetric system). L* represents lightness, a* represents redness-greenness, and b* represents yellowness-blueness. The corresponding differences ΔL*, Δa*, and Δb* are determined based on the initial and final L*, a*, and b* values ​​of the sample.

[0148] To more closely approximate the actual working conditions of the dye, 0.5% of the azo dye compound provided by this invention and the azo dye compound of the comparative example were added to the parent liquid crystal 1 as test samples. The samples were heated and stirred at 120°C for 1 hour, then spotted using a TN-7.0 test box, sealed, and the initial value of the sample was measured by spectroscopy. The final value was measured after different extreme conditions. The color difference was determined based on the initial and final values, and the results are shown in Table 12.

[0149] As shown in Table 12, after 168 hours of UV irradiation, the color difference values ​​of the azo dye compounds provided by this invention are all within 4, while the color difference values ​​of azo dye compounds D1 to D3 are all above 10, with D1 and D3 even exceeding 15. The smaller the color difference value, the better the stability of the dye. Therefore, the azo dye compounds provided by this invention obtained relatively good color difference ΔE* values ​​after UV irradiation. After 1000 hours of high temperature, the color difference values ​​of D1 to D3 all exceed 5. After 1000 hours of high temperature and high humidity, the color difference values ​​of D1 to D3 are all above 7. In contrast, the color difference values ​​of the azo dye compounds provided by this invention are all below 3, obtaining very good color difference ΔE* values. Therefore, the azo dye compounds provided by this invention can maintain small color difference changes after 168 hours of UV irradiation, 1000 hours of high temperature at 85℃, and 1000 hours of high temperature at 85℃ and high humidity at 85%, exhibiting excellent stability and durability.

[0150] Table 12 Color difference test results under extreme conditions (UV, high temperature, high temperature and high humidity) Time compounds After 168 hours of UV light exposure After 1000 hours of high temperature After 1000 hours of high temperature and high humidity D1 18.6 5.2 8.8 D2 12.3 5.1 7.1 D3 15.3 5.6 7.8 I-111-1 3.2 1.8 2.5 I-111-2 2.7 1.5 2.3 I-111-4 2.2 1.0 1.5 I-111-5 3.3 2.0 2.6 I-111-6 3.5 2.3 2.7 I-211-1 3.2 1.9 2.4 I-211-2 3.4 2.3 2.6 I-211-4 3.6 2.6 2.9 I-311-1 3.5 2.5 2.6 I-321-2 3.2 2.0 2.5 I-331-2 3.0 1.6 2.3 The azo dye compounds provided by this invention exhibit high dichroism ratios and good solubility in liquid crystal materials. They also demonstrate low color difference, excellent stability, and durability under extreme environmental conditions (UV, high temperature, high temperature and high humidity). Therefore, the azo dye compounds of Formula I of this invention possess superior optical properties and stability, meeting the requirements for dye performance and long-term use in extreme environments for products such as dimming elements.

[0151] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions or improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An azo dye compound, characterized in that, Its structural formula is shown in Formula I: Formula I; In the formula, , , , , , and Represented independently or ; L1 to L7 represent hydrogen atoms, halogen atoms, C1 to C15 alkyl groups, or C1 to C15 alkoxy groups, respectively. R1 to R4 represent, independently, a hydrogen atom, a C1 to C15 alkyl group, a C1 to C15 substituted alkyl group, a C2 to C15 alkyl group containing an ester group, a C3 to C15 alkenyl group, a C3 to C15 alkynyl group, a C2 to C15 alkyl group containing an ether group, or a C2 to C15 alkyl group containing a thioether group. Z1 represents a nitrogen atom, an oxygen atom, or a sulfur atom; when Z1 represents a nitrogen atom, m=1; when Z1 represents an oxygen atom or a sulfur atom, m=0. Z2 represents a nitrogen atom, an oxygen atom, or a sulfur atom; when Z2 represents a nitrogen atom, n=1; when Z2 represents an oxygen atom or a sulfur atom, n=0. x represents 0 or 1, and y represents 0 or 1.

2. The azo dye compound according to claim 1, characterized in that, express ; and / or express ; and / or express ; and / or express ; and / or L1 to L7 independently represent a hydrogen atom, a halogen atom, a C1-C5 straight-chain alkyl group, or a C1-C5 straight-chain alkoxy group; and / or R1 represents a hydrogen atom, a C1-C10 straight-chain alkyl group, a C4-C15 cycloalkyl group, or a C1-C10 halo-straight-chain alkyl group; and / or R2 represents a hydrogen atom, a C1-C10 straight-chain alkyl group, a C4-C15 cycloalkyl group, a C1-C10 haloalkyl group, or a C3-C10 straight-chain alkyl group containing an ester group; and / or R3 represents a hydrogen atom, a C1-C10 straight-chain alkyl group, a C4-C15 cycloalkyl group, or a C1-C10 halo-straight-chain alkyl group; and / or R4 represents a hydrogen atom, a C1-C10 straight-chain alkyl group, a C4-C15 cycloalkyl group, a C1-C10 haloalkyl group, or a C3-C10 straight-chain alkyl group containing an ester group.

3. The azo dye compound according to claim 1 or 2, characterized in that, The structural formulas of the azo dye compounds are shown in Formula I-11, Formula I-21, Formula I-31, Formula I-32 or Formula I-33: Formula I-11 Formula I-21 Formula I-31 Formula I-32 Formula I-33.

4. The azo dye compound according to claim 1 or 2, characterized in that, The structural formulas of the azo dye compounds are shown in Formula I-111, Formula I-211, Formula I-311, Formula I-321, or Formula I-331: Formula I-111 Formula I-211 Formula I-311 Formula I-321 Formula I-331; In the formula, L3 represents -H, -F, or -CH3; L4 represents -H or -F; L 51 Indicates -H or -F, L 52 Indicates -H or -F, and L 51 and L 52 Do not both represent -F; L6 represents -H, -F, or -CH3.

5. The azo dye compound according to claim 1 or 2, characterized in that, The azo dye compounds include at least one of the following: compounds with the structure shown in Formula I-111-1 to Formula I-111-7, Formula I-211-1 to Formula I-211-4, Formula I-311-1, Formula I-321-1, Formula I-321-2, Formula I-331-1, or Formula I-331-2. Formula I-111-1 Formula I-111-2 Formula I-111-3 Formula I-111-4 Formula I-111-5 Formula I-111-6 Formula I-111-7 Formula I-211-1 Formula I-211-2 Formula I-211-3 Formula I-211-4 Formula I-311-1 Formula I-321-1 Formula I-321-2 Formula I-331-1 Formula I-331-2.

6. A liquid crystal composition, characterized in that, It includes the azo dye compound according to any one of claims 1 to 5.

7. The liquid crystal composition according to claim 6, characterized in that, The liquid crystal composition further comprises a parent liquid crystal, an ultraviolet absorber, and a sterically hindered phenolic antioxidant.

8. The liquid crystal composition according to claim 7, characterized in that, The mass ratio of the azo dye compound to the parent liquid crystal is 0.05:100 to 5:100; and / or The mass ratio of the ultraviolet absorber to the parent liquid crystal is 0.1:100 to 0.7:100; and / or The mass ratio of the sterically hindered phenolic antioxidant to the parent liquid crystal is 0.01:100 to 0.07:

100.

9. The use of the azo dye compound according to any one of claims 1 to 5 in the preparation of dimming elements.

10. The use of the liquid crystal composition according to any one of claims 6 to 8 in the preparation of a dimming element.

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