Dichroic dye compound and application thereof
By designing dichroic dye compounds with specific structures, the problem of instability of dyes for liquid crystals under ultraviolet light was solved, thereby improving the contrast and stability of liquid crystal display devices.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-02-13
- Publication Date
- 2026-04-07
AI Technical Summary
Existing dichroic dyes used in liquid crystals are unstable under ultraviolet light, affecting the stability and contrast of liquid crystal display devices.
A dichroic dye compound is provided, which is designed as an azo compound with a specific structure, has a large order parameter and excellent stability, and can be miscible with liquid crystal compounds, and can be used in mixed liquid crystal materials.
It improves the contrast ratio of the LCD display device, and enhances the stability and display effect of the LCD display device.
Smart Images
Figure CN121801347A_ABST
Abstract
Description
Technical Field
[0001] This application belongs to the field of liquid crystal display technology, specifically relating to a dichroic dye compound and its application. Background Technology
[0002] Digital display has become the mainstream display technology in the 21st century. Compared with other display technologies, liquid crystal displays have the characteristics of low voltage, low power consumption, and portability, and are easy to achieve in thin, light and large flat panel displays.
[0003] In liquid crystal display materials, dye-based liquid crystals operate in a host-guest configuration. Nematic liquid crystals serve as the host display material, while dyes act as additives, miscible with the liquid crystal material. When an electric current is applied, the movement of liquid crystal molecules carries the dye molecules along with them, achieving the display effect. Therefore, the dyes used in liquid crystal displays must have excellent compatibility with the liquid crystal material, a molecular structure similar to that of the liquid crystal molecules, and excellent chemical, optical, and thermal stability. Multicolor dye-based liquid crystals, with their high contrast, clear display, and aesthetically pleasing content, have long been favored by high-end products such as automotive dashboards and smart windows.
[0004] There are many types of dyes used in liquid crystals, including azo, anthraquinone, azazine, and oxanthracene dyes. These dyes must have excellent compatibility with the liquid crystal components and, when added to the mixed liquid crystal, not reduce the stability of the mixed liquid crystal material. Under the influence of an electric field, they can twist synchronously with the liquid crystal molecules, possessing the same orientation vector as the liquid crystal molecules. When displayed, they produce very bright colors, and when turned off, they are colorless.
[0005] Among dichroic dyes for liquid crystals, azo compounds, with their rod-shaped molecular structure, exhibit good compatibility and stability with liquid crystal materials. When doped with liquid crystals, they display excellent photoelectric properties, such as wide viewing angles and increased brightness, and are therefore widely used in dye-based liquid crystals. However, these dyes are unstable under ultraviolet light. Summary of the Invention
[0006] To solve at least one of the above-mentioned technical problems, this application provides a dichroic dye compound and its application. The dichroic dye compound provided by this application has a large order parameter, is miscible with liquid crystal compounds, and has excellent stability and miscibility. It can be widely used in mixed liquid crystal materials, so that the liquid crystal display device using it has better contrast.
[0007] In a first aspect, this application provides a dichroic dye compound having a structure as shown in Formula I or Formula II: Formula I; Formula II; R1 is selected from H, straight-chain alkyl or branched alkyl with 1 to 10 carbon atoms, and R2 is selected from any one of H, F, N(R3)2, straight-chain alkyl or branched alkyl with 1 to 10 carbon atoms that are substituted or unsubstituted by F, alkoxy with 1 to 10 carbon atoms that are substituted or unsubstituted by F, alkenyl with 2 to 10 carbon atoms that are straight-chain alkyl or branched alkyl with 3 to 5 carbon atoms. R3 is selected from any one of the following: a straight-chain alkyl or branched alkyl group with 1 to 10 carbon atoms that is F-substituted or unsubstituted; an alkenyl group with 2 to 10 carbon atoms that is F-substituted or unsubstituted; or a cycloalkyl group with 3 to 5 carbon atoms. X1 and X2 each independently contain H, CH3, C2H5, C3H7, C4H9, CH2CH(CH3)2, F, and Cl; A1 and A2 are each independent single bonds or any of the following structures: , , , , , ; A3 and A4 are each independently selected from a single bond or any of the following structures: , , , , , , , , , , , ; Z1 and Z2 are independently selected from any one of the following: single bond, -CH2-, -CH2CH2-, -CH2O-, -N=N-, and -CF2O-; a and b are independently selected from 1 or 2; *—、—* represents the connecting bond of a group.
[0008] In some preferred embodiments, R1 in Formula I and Formula II is selected from H, a straight-chain alkyl or branched alkyl with 1 to 8 carbon atoms; R2 is selected from any one of H, a straight-chain alkyl or branched alkyl with 1 to 8 carbon atoms, an alkoxy with 1 to 8 carbon atoms, an F-substituted straight-chain alkyl or branched alkyl with 1 to 6 carbon atoms, an F-substituted alkoxy with 1 to 6 carbon atoms, and a cycloalkyl with 3 to 5 carbon atoms.
[0009] In some preferred embodiments, the above-mentioned dichroic dye compound has the structure shown in Formula I, specifically any one of the following compounds:
[0010]
[0011]
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[0014]
[0015]
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[0018]
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[0020]
[0021]
[0022]
[0023]
[0024]
[0025]
[0026] In some preferred embodiments, the above-mentioned dichroic dye compound has the structure shown in Formula II, specifically any one of the following compounds:
[0027]
[0028]
[0029]
[0030]
[0031]
[0032]
[0033]
[0034]
[0035]
[0036]
[0037]
[0038] Unless otherwise specified in this article, "-C" n H 2n+1 " indicates an alkyl group (e.g., -C3H7, -C4H9, -C5H) 11 (etc.) all refer to straight-chain alkyl groups.
[0039] A second aspect of this application provides a liquid crystal composition comprising any one or more of the dichroic dye compounds described in the first aspect.
[0040] In some preferred embodiments, the liquid crystal composition further includes a host material comprising any one or more of the following compounds:
[0041] Among them, R6, R7, R8, R9, R 10 R11 R 12 Each is independently selected from any one of H, F, F-substituted or unsubstituted straight-chain or branched alkyl groups with 1 to 10 carbon atoms, F-substituted or unsubstituted alkoxy groups with 1 to 10 carbon atoms, F-substituted or unsubstituted alkenyl groups with 2 to 10 carbon atoms, or F-substituted or unsubstituted cycloalkyl groups with 3 to 5 carbon atoms.
[0042] The content of the dichroic dye compound, calculated as 100% of the total mass of the liquid crystal composition, is 0.1%-15%, for example, 0.1%, 0.5%, 1%, 3%, 5%, 8%, 10%, 12%, 15%, etc. However, this application is not limited to the listed values, and other unlisted values within this range are also applicable. More preferably, the content of the dichroic dye compound, calculated as 100% of the total mass of the liquid crystal composition, is 0.1%-10%.
[0043] Thirdly, this application provides the application of the dichroic dye compound described in the first aspect or the liquid crystal composition described in the second aspect in a liquid crystal display device. The liquid crystal display device includes, but is not limited to, VA (Vertical Alignment) liquid crystal displays, TN (Twisted Nematic) liquid crystal displays, STN (Super-twisted Nematic) liquid crystal displays, FFS (Fringing Field Switching) liquid crystal displays, IPS (In Plane Switching) liquid crystal displays, automotive instrument panels, and smart windows.
[0044] The beneficial effects of this application are as follows: the dichroic dye compound provided in this application has a large order parameter, which can be widely used in mixed liquid crystal materials, so that the liquid crystal display device using it has better contrast. Detailed Implementation
[0045] The following will provide a clear and complete description of the concept and technical effects of this application in conjunction with embodiments, so as to fully understand the purpose, solution and effects of this application. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other.
[0046] Example 1 A dichroic dye compound, BYLC-01, has the following structural formula: .
[0047] The synthetic route is shown below: .
[0048] The specific synthesis steps are as follows: 1. Synthesis of BYLC-01-3 Add 134 g BYLC-01-2 (2-thiopheneboronic acid), 240 g BYLC-01-1, 400 mL tetrahydrofuran, and 600 mL water to a clean, dry 2 L three-necked flask. Start stirring, add 77.4 g sodium bicarbonate and 12.3 g tetrabutylammonium bromide, and continuously purge with nitrogen for 5 minutes. Add 0.3 g palladium 0132, and heat to reflux (about 70 °C). Reflux for 3 hours.
[0049] Post-treatment: The reaction solution was cooled to room temperature, and 200 mL of water and 200 mL of toluene were added. The mixture was stirred for 5 minutes and separated. The aqueous phase was extracted with 200 mL of toluene. The combined organic phases were washed once with 300 mL of water, and the organic phase was concentrated to 243 g of brownish-black liquid. The solution was diluted with twice the volume of n-heptane, passed through an 80 g silica gel column, flushed with twice the column height of n-heptane, and concentrated to dryness to 218.7 g of green liquid. GC 99%.
[0050] Theoretical yield: 243 g, actual yield: 218.7 g, yield: 90%, m / z: 230 (M+).
[0051] 2. Synthesis of BYLC-01-4 Add 1 L of tetrahydrofuran and 85 g of BYLC-01-3 to a clean, dry 2 L three-necked flask, start stirring, and maintain a nitrogen atmosphere throughout. Cool to -75 ℃ to -85 ℃ with liquid nitrogen, and add 180 mL of butyllithium dropwise. After the addition is complete, maintain the temperature at -70 ℃ to -80 ℃ and react for 2 h. Then, maintain the temperature at -70 ℃ to -80 ℃ and add 114 g of tributyltin chloride dropwise. After the addition is complete, allow the temperature to return to normal and react for 2 h.
[0052] Post-treatment: Maintaining the temperature below 20 °C, add 100 mL of dilute hydrochloric acid (hydrochloric acid:water = 1:1) dropwise to the reaction solution, stir for 10 minutes, then add 200 mL of water, and stir at -15 °C for 2 hours. Filter, and wash the filter cake once with water. Then add 0.5 times THF and 3 times n-heptane, boil at 50 °C for 0.5 hours, stir at -15 °C for 2 hours, filter, and obtain 90.4 g, with 99% purity as determined by liquid chromatography.
[0053] Theoretical yield: 186.3 g, actual yield: 167.7 g, yield: 90%, m / z: 532.4 (M+).
[0054] 3. Synthesis of BYLC-01-6 In a clean, dry 500 mL three-necked flask, add 74 g of BYLC-01-4, 56 g of BYLC-01-5, and 100 mL of tetrahydrofuran in sequence. Purge with nitrogen for 5 minutes, then add 0.1 g of bis(triphenylphosphine)palladium chloride. Heat to reflux (about 70°C) and reflux for 5 hours.
[0055] Post-processing: The reaction solution was cooled to room temperature, and 300 mL of water, 50 mL of n-heptane, and 50 mL of THF were added. The mixture was stirred for 10 minutes and separated. The aqueous phase was extracted once with 50 mL of n-heptane and 50 mL of THF. The organic phases were combined and passed through a 10 g silica gel column. The column was flushed with 2 times the column height of n-heptane. The column buffer was concentrated to 40 g at 70 ℃. 10 times the volume of n-heptane was added and stirred at room temperature (19 ℃) for 20 min. The mixture was then frozen (-17 ℃) for 3 h and immediately filtered to obtain 20 g of purplish-black powder, which is BYLC-01-6.
[0056] Theoretical yield was 79 g, actual yield was 47.4 g, yield was 60%, liquid chromatography purity was 99%, m / z was 563,565 (M+).
[0057] 4. Synthesis of BYLC-01 In a clean, dry 500 mL three-necked flask, add 45.1 g BYLC-01-6, 39.3 g BYLC-01-7, and 100 mL tetrahydrofuran in sequence. Purge with nitrogen for 5 minutes, then add 0.1 g bis(triphenylphosphine)palladium chloride. Heat to reflux (approximately 70 °C) and reflux for 5 hours.
[0058] Post-processing: The reaction solution was cooled to room temperature, and 300 mL of water, 50 mL of toluene, and 50 mL of THF were added. The mixture was stirred for 10 minutes and separated. The aqueous phase was extracted once with 50 mL of toluene and 50 mL of THF. The organic phases were combined and passed through a 10 g silica gel column. The column was flushed with toluene at twice the column height. The column buffer was concentrated to 40 g at 70 ℃. Five times the volume of toluene was added and the mixture was stirred at room temperature (19 ℃) for 20 min. The mixture was then frozen (-15 ℃) for 3 h and immediately filtered to obtain 27.7 g of purplish-black powder, which is BYLC-01.
[0059] Theoretical yield was 54.9 g, actual yield was 33 g, yield was 60%, liquid chromatography purity was 99%, and the m / z of the product was 685 (M+).
[0060] Example 2 A dichroic dye compound, BYLC-02, has the following structural formula: .
[0061] The preparation method is the same as in Example 1, except that BYLC-01-7 is replaced with .
[0062] The obtained solid BYLC-02 was analyzed by HPLC-MS, and the m / z of the product was 788 (M+).
[0063] Example 3 A dichroic dye compound, BYLC-03, has the following structural formula: .
[0064] The preparation method is the same as in Example 1, except that BYLC-01-7 is replaced with .
[0065] The obtained solid BYLC-03 was analyzed by HPLC-MS, and the m / z of the product was 787 (M+).
[0066] Example 4 A dichroic dye compound, BYLC-04, has the following structural formula: .
[0067] The preparation method is the same as in Example 1, except that BYLC-01-1 is replaced with .
[0068] Replace BYLC-01-7 with .
[0069] The obtained solid BYLC-04 was analyzed by HPLC-MS, and the m / z of the product was 844 (M+).
[0070] Example 5 A dichroic dye compound, BYLC-05, has the following structural formula: .
[0071] The preparation method is the same as in Example 1, except that BYLC-01-7 is replaced with .
[0072] The obtained solid BYLC-05 was analyzed by HPLC-MS, and the m / z of the product was 826 (M+).
[0073] Example 6 A dichroic dye compound, BYLC-06, has the following structural formula: .
[0074] The preparation method is the same as in Example 1, except that BYLC-01-5 is replaced with .
[0075] The obtained solid BYLC-06 was analyzed by HPLC-MS, and the m / z of the product was 713 (M+).
[0076] Example 7 A dichroic dye compound, BYLC-07, has the following structural formula: .
[0077] The preparation method is the same as in Example 1, except that BYLC-01-5 is replaced with Replace BYLC-01-7 with .
[0078] The obtained solid BYLC-07 was analyzed by HPLC-MS, and the m / z of the product was 798 (M+).
[0079] Example 8 A dichroic dye compound, BYLC-08, has the following structural formula: .
[0080] The preparation method is the same as in Example 1, except that BYLC-01-5 is replaced with Replace BYLC-01-7 with .
[0081] The obtained solid BYLC-08 was analyzed by HPLC-MS, and the m / z of the product was 818.5 (M+).
[0082] Example 9 A dichroic dye compound, BYLC-9, has the following structural formula: .
[0083] The preparation method is the same as in Example 1, except that BYLC-01-1 is replaced with .
[0084] The obtained solid BYLC-9 was analyzed by HPLC-MS, and the m / z of the product was 671 (M+).
[0085] Example 10 A dichroic dye compound, BYLC-10, has the following structural formula: .
[0086] The preparation method is the same as in Example 1, except that BYLC-01-1 is replaced with BYLC-01-7 replaced with .
[0087] The obtained solid BYLC-10 was analyzed by HPLC-MS, and the m / z of the product was 689 (M+).
[0088] Example 11 A dichroic dye compound, BYLC-11, has the following structural formula: .
[0089] The preparation method is the same as in Example 1, except that BYLC-01-1 is replaced with BYLC-01-7 replaced with .
[0090] The obtained solid BYLC-11 was analyzed by HPLC-MS, and the m / z of the product was 719 (M+).
[0091] Example 12 A dichroic dye compound, BYLC-12, has the following structural formula: .
[0092] The preparation method is the same as in Example 1, except that BYLC-01-1 and BYLC-01-7 are replaced with... , .
[0093] The obtained solid BYLC-12 was analyzed by HPLC-MS, and the m / z of the product was 812 (M+).
[0094] Example 13 A dichroic dye compound, BYLC-13, has the following structural formula: .
[0095] The preparation method is the same as in Example 1, except that BYLC-01-1 and BYLC-01-7 are replaced with... , .
[0096] The obtained solid BYLC-13 was analyzed by HPLC-MS, and the m / z of the product was 774 (M+).
[0097] Example 14 A dichroic dye compound, BYLC-14, has the following structural formula: .
[0098] The preparation method is the same as in Example 1, except that BYLC-01-1 and BYLC-01-7 are replaced with... , .
[0099] The obtained solid BYLC-14 was analyzed by HPLC-MS, and the m / z of the product was 773 (M+).
[0100] Performance testing The dichroic dye compound CP-1 (a Merck patent) was used as a comparative example, and its structure is shown below: .
[0101] This test case provides the performance of the dyes in each example and comparative example, as detailed below: The dye compounds provided in each embodiment and comparative example were mixed with the host material BLC-2510 at a mass ratio of 1:100 to obtain liquid crystal compositions. The specific composition of the host material BLC-2510 is shown in Table 1.
[0102] Table 1
[0103] Test method for the order parameter S: The order parameter S of the liquid crystal composition is tested using a UV730 spectrophotometer. The wavelength at which the light transmittance is lowest is its characteristic wavelength λ. The parallel light transmittance at this wavelength is T. ∥ Vertical light transmittance is T ⊥ Substituting the transmittance in each direction into the Lambert-Beer law A=-lg T, the absorbance A in both directions is easily obtained. ∥ A ⊥ The ordered parameter is S=(A ∥ -A ⊥ ) / (A ∥ +2A ⊥ ).
[0104] The test results are shown in Table 2: Table 2
[0105] As can be seen from Table 2, compared with the existing compound CP-1, the compound provided in the embodiments of this application has a larger order parameter, which enables the liquid crystal display device to have better contrast.
[0106] The above description is merely a preferred embodiment of this application. This application is not limited to the above-described embodiments. Any embodiment that achieves the technical effect of this application using the same means should fall within the protection scope of this application. Within the protection scope of this application, the technical solutions and / or implementation methods can have various modifications and variations.
Claims
1. A dichroic dye compound, characterized in that, The dichroic dye compound has a structure as shown in Formula I or Formula II: Formula I; Formula II; R1 is selected from H, straight-chain alkyl or branched alkyl with 1 to 10 carbon atoms, and R2 is selected from any one of H, F, N(R3)2, straight-chain alkyl or branched alkyl with 1 to 10 carbon atoms that are substituted or unsubstituted by F, alkoxy with 1 to 10 carbon atoms that are substituted or unsubstituted by F, alkenyl with 2 to 10 carbon atoms that are straight-chain alkyl or branched alkyl with 3 to 5 carbon atoms. R3 is selected from any one of the following: a straight-chain alkyl or branched alkyl group with 1 to 10 carbon atoms that is F-substituted or unsubstituted; an alkenyl group with 2 to 10 carbon atoms that is F-substituted or unsubstituted; or a cycloalkyl group with 3 to 5 carbon atoms. X1 and X2 are each independently selected from H, CH3, C2H5, C3H7, C4H9, CH2CH(CH3)2, F, and Cl; A1 and A2 are each independently selected from a single bond or any of the following structures: 、 、 、 、 、 ； A3 and A4 are each independently selected from a single bond or any of the following structures: 、 、 、 、 、 、 、 、 、 、 、 ； Z1 and Z2 are independently selected from any one of the following: single bond, -CH2-, -CH2CH2-, -CH2O-, -N=N-, and -CF2O-; a and b are independently selected from 1 or 2; *—、—* represent the connecting bonds of functional groups.
2. The dichroic dye compound according to claim 1, characterized in that, R1 is selected from H, a straight-chain alkyl or branched alkyl group with 1 to 8 carbon atoms; R2 is selected from any one of H, a straight-chain alkyl or branched alkyl group with 1 to 8 carbon atoms, an alkoxy group with 1 to 8 carbon atoms, an F-substituted straight-chain alkyl or branched alkyl group with 1 to 6 carbon atoms, an F-substituted alkoxy group with 1 to 6 carbon atoms, and a cycloalkyl group with 3 to 5 carbon atoms.
3. The dichroic dye compound according to claim 1 or 2, characterized in that, The dichroic dye compound has the structure shown in Formula I, and the dichroic dye compound is any one of the following compounds:
4. The dichroic dye compound according to claim 1 or 2, characterized in that, The dichroic dye compound has the structure shown in Formula II, and the dichroic dye compound is any one of the following compounds:
5. A liquid crystal composition, characterized in that, The liquid crystal composition comprises any one or more of the dichroic dye compounds according to any one of claims 1-4.
6. The liquid crystal composition according to claim 5, characterized in that, The liquid crystal composition further includes a host material, which comprises any one or more of the following compounds: Among them, R6, R7, R8, R9, R 10 R 11 R 12 Each is independently selected from any one of H, F, F-substituted or unsubstituted alkyl groups of 1 to 10 carbon atoms, F-substituted or unsubstituted alkoxy groups of 1 to 10 carbon atoms, F-substituted or unsubstituted alkenyl groups of 2 to 10 carbon atoms, and cycloalkyl groups of 3 to 5 carbon atoms.
7. The liquid crystal composition according to claim 5 or 6, characterized in that, The content of the dichroic dye compound is 0.1%-15% based on the total mass of the liquid crystal composition as 100%.
8. The liquid crystal composition according to claim 7, characterized in that, The content of the dichroic dye compound is 0.1%-10% based on the total mass of the liquid crystal composition as 100%.
9. The use of the dichroic dye compound according to any one of claims 1-4 or the liquid crystal composition according to any one of claims 5-8 in a liquid crystal display device.
10. The application according to claim 9, characterized in that, The liquid crystal display device includes VA liquid crystal display, TN liquid crystal display, STN liquid crystal display, FFS liquid crystal display, IPS liquid crystal display, automotive instrument panel, and smart window.