Yellow dichroic dye and application thereof

Abstract

The invention relates to the technical field of display materials, in particular to a yellow dichroic dye and application thereof. The structural general formula of the yellow dichroic dye is as follows: # imgabs0 # R1, R2 and R3 are respectively and independently selected from H, C1-C20 alkyl groups, C6-C12 cycloalkyl groups, C1-C20 alkoxy groups, C6-C12 cycloalkyloxy groups, C1-C20 alkylamino groups, substituted or unsubstituted C6-C50 aryl groups, substituted or unsubstituted C2-C50 heteroaryl groups, allyl groups, acyl groups, amino groups, C2-C10 acylamino groups, C2-C10 acyloxy groups and the like; x1 is hydrogen, nitrogen, sulfur or halogen, and L is selected from phenylene or naphthylene. The yellow dichroic dye has excellent application performance in a liquid crystal matrix, and is better in environmental protection performance and simpler in preparation process.

Description

Technical Field

[0001] The invention relates to a yellow dichroic dye and application thereof, belonging to the technical field of display materials. Background Art

[0002] Liquid crystal display technology is widely used in display devices such as televisions, computers, and mobile phones due to its advantages of low power consumption, lightness, and wide viewing angle. Liquid crystal dyes, as a key component of liquid crystal displays, directly affect the color expression and performance of the display. Yellow liquid crystal dyes, as one of the three primary colors, are of great significance for achieving full-color display.

[0003] Existing yellow liquid crystal dyes have certain limitations in terms of color performance, stability and environmental performance. The main problems are as follows:

[0004] (1) The color expression is insufficient, and it is difficult to achieve a bright and pure yellow display;

[0005] (2) Poor thermal stability, easy to change color in high temperature environment, affecting the display effect;

[0006] (3) Poor environmental performance. Some dyes contain harmful substances, which pose potential hazards to the environment and human health.

[0007] (4) The preparation process is complicated and the production cost is high.

[0008] Therefore, it is of great practical significance to develop a yellow dichroic liquid crystal dye with excellent color expression, high thermal stability and good environmental performance.

[0009] In the research and development of yellow dichroic dyes, new yellow anthraquinone dichroic dyes with naphthylthio groups were synthesized in U.S. patent application US20230340268A1. These dyes show excellent performance in guest-host liquid crystal displays, such as the specific compound 37Y, whose structure is as follows. However, this type of anthraquinone yellow dye has poor absorbance, and a larger amount of material needs to be added to absorb more blue light to achieve a brighter yellow. Because the increase in the amount of addition will affect the corresponding performance of the main liquid crystal to the electric field, it is also easy to cause crystallization of the dye in the liquid crystal. Therefore, it is necessary to develop a yellow dye with high absorption rate, so that a small amount of addition can achieve yellow color development without affecting the performance of the main liquid crystal.

[0010]

[0011] At present, the development of the dye industry has more and more requirements for environmental protection. This has led to environmental pressure on the dye industry, but it has also promoted the development of more environmentally friendly and efficient technologies. Therefore, the development trend of the entire dye industry is moving towards a more environmentally friendly, high-quality and functional direction. Therefore, it is of great value to develop and apply yellow dichroic dyes with excellent application performance and environmental protection. Summary of the invention

[0012] The present invention aims at the deficiencies of the prior art and provides a yellow dichroic dye and its application. The yellow dichroic dye has excellent performance when used in a liquid crystal matrix, especially has stronger absorption in the blue light region, and has good dichroism.

[0013] The technical solution of the present invention to solve the above technical problems is as follows: a yellow dichroic dye, the general structural formula of the yellow dichroic dye is as follows (I):

[0014]

[0015] In formula (I), R1 and R2 are independently selected from H, C1-C20 alkyl, C6-C12 cycloalkyl, C1-C20 alkoxy, C6-C12 cycloalkyloxy, C1-C20 alkylamino, substituted or unsubstituted C6-C50 aryl, substituted or unsubstituted C2-C50 heteroaryl, allyl, acyl, amino, C2-C10 acylamino, C2-C10 acyloxy; the substituents in R1 and R2 are selected from hydroxyl, C1-C12 alkyl, C1-C20 alkoxy or carboxyl;

[0016] R3 is selected from H, substituted or unsubstituted C1-C12 alkyl, C2-C6 alkenyl, substituted or unsubstituted C1-C18 alkoxy, C1-C18 alkylamino, C5-C12 cycloalkyloxy, C2-C18 alkenyloxy, -C≡N, C1-C4 haloalkyl, sulfo, acyl, C2-C18 acylamino, C2-C18 acyloxy, substituted or unsubstituted C6-C50 aryl, substituted or unsubstituted C2-C50 heteroaryl; the substituent in R3 is selected from C1-C18 alkyl, C1-C18 alkoxy or halogen;

[0017] The heteroatom of the heteroaryl group is oxygen, nitrogen or sulfur;

[0018] X1 is hydrogen, nitrogen, sulfur or halogen;

[0019] L is selected from phenylene or naphthylene.

[0020] Preferably, R1 and R2 are independently selected from C1-C20 alkyl, cyclohexyl, C1-C20 alkoxy, C1-C20 alkylamino, cyclohexyloxy, allyl, amino, acyl, C2-C10 acylamino, C2-C10 acyloxy; substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted C2-C30 heteroaryl.

[0021] More preferably, R1 and R2 are independently selected from C1-C20 alkyl, substituted or unsubstituted C6-C18 aryl, substituted or unsubstituted C2-C18 heteroaryl.

[0022] More preferably, R1 and R2 are independently selected from the following structures:

[0023]

[0024] Preferably, R3 is selected from C1-C8 alkyl, allyl, C1-C4 alkoxy, C1-C4 alkylamino, C1-C18 alkyl substituted by C1-C4 alkoxy or halogen, C1-C4 alkoxy substituted by C1-C4 alkoxy or halogen, acyl, C2-C10 acylamino, C2-C10 acyloxy, substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted C2-C30 heteroaryl.

[0025] More preferably, R3 is selected from C1-C8 alkyl; substituted or unsubstituted C6-C18 aryl, substituted or unsubstituted C2-C18 heteroaryl.

[0026] More preferably, R3 is selected from any one of the following structures:

[0027]

[0028] Preferably, X1 is hydrogen or nitrogen; and L is selected from any one of the following structures:

[0029]

[0030] More preferably, the yellow dichroic dye is selected from any one of the following structural formulas:

[0031]

[0032]

[0033]

[0034]

[0035]

[0036]

[0037]

[0038]

[0039] The invention also discloses an application of a yellow dichroic dye. The yellow dichroic dye is combined with a liquid crystal matrix to form a guest-host liquid crystal composition which is applied to a liquid crystal display device.

[0040] The beneficial effects of the present invention are:

[0041] The yellow dichroic dye of the present invention has excellent solubility, excellent light transmittance in the visible light range, excellent solubility and thermal stability, and the dichroic ratio in the main yellow absorption wavelength range (especially 430-470nm) is further improved, thereby achieving higher color contrast and clearer display effects, meeting the needs of high-contrast display.

[0042] The yellow dichroic dye of the present invention has a specific chemical structure formula, which contains a variety of substitutable groups. By adjusting the types and quantities of these groups, the precise control of the dye performance can be achieved. By optimizing the molecular structure of the dye, its solubility in the liquid crystal matrix is ​​significantly improved, ensuring that the dye can be uniformly and stably present in the liquid crystal system. The thermal stability is significantly improved, and it is not easy to change color under high temperature environment, maintaining a good display effect. While maintaining excellent solubility, the yellow dichroic dye of the present invention has excellent light transmittance in the visible light range.

[0043] In addition, the yellow dichroic dye of the present invention has stable performance and a simpler preparation process. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 This is the spectrum diagram of HSYD01;

[0045] Figure 2 This is the high temperature aging spectrum of HSYD01;

[0046] Figure 3 UV-Vis absorption spectra of HSYD01 and 37Y in toluene. DETAILED DESCRIPTION

[0047] The specific implementation of the present invention is described in detail below. The present invention can be implemented in many other ways than those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention, so the present invention is not limited by the specific embodiments disclosed.

[0048] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which the present invention belongs. The terms used are only for describing specific embodiments and are not intended to limit the present invention.

[0049] 1. Preparation and Synthesis Example

[0050] Synthesis example 1

[0051]

[0052] (Preparation of A)

[0053] A 100 mL round-bottom flask was taken, and 2-chloropyrimidine-5-carboxylic acid (6.30 mmol), dichloromethane (20 mL) and DMF (0.2 mL) were added respectively, and then oxalyl chloride (9.45 mmol) was slowly added dropwise at 0°C. After the addition was completed, the reaction was continued at room temperature for 2 h. The reaction system was concentrated to remove the solvent to obtain 2-chloropyrimidine-5-carbonyl chloride. Another 100 mL round-bottom flask was taken, and 2-methyl-1-butanol (6.3 mmol), dichloromethane (20 mL), DMAP (1.26 mmol) and triethylamine (9.45 mmol) were added respectively. Then a dichloromethane solution (10 mL) of 2-chloropyrimidine-5-carbonyl chloride was slowly added dropwise at 0°C. After the addition was completed, the reaction was continued at room temperature for 2 h. The reaction system was quenched with water, extracted three times with dichloromethane, the organic phases were combined, dried, and the solution was concentrated and separated by silica gel column chromatography to obtain product A (yield 81%).

[0054] (Preparation of B)

[0055] Compound A (5mmol), 4-bromo-2-methoxyphenylboronic acid (6mmol), K2CO3 (10mmol), Pd(PPh3)4 (0.25mmol) were added to a 250mL thick-walled reaction tube, Dioxane (40mL) and H2O (10mL) were added, and the reaction system was reacted at 80°C for 12h. After the reaction was completed, the system was concentrated and separated by silica gel column chromatography to obtain product B (yield 49%).

[0056] (Preparation of C)

[0057] Compound B (2mmol), p-dimethylaminophenylboronic acid (2.4mmol), K2CO3 (4mmol), and Pd(PPh3)4 (0.1mmol) were added to a 100mL thick-walled reaction tube, and Dioxane (20mL) and H2O (5mL) were added. After the reaction was completed, the system was concentrated and separated by silica gel column chromatography to obtain product C (yield 82%).

[0058] (Preparation of D)

[0059] Compound C (1 mmol) was dissolved in DCM (10 mL), and then 2 M BBr3 (4 mmol) solution was slowly added dropwise in an ice bath. The reaction was allowed to react for about 5 h. After the reaction was complete, methanol was added to the system in an ice bath to quench the reaction. The mixture was stirred for 1 h, and then the system was spin-dried and separated by silica gel column chromatography to obtain product D (yield 52%).

[0060] Synthesis example 2

[0061]

[0062] (Preparation of A)

[0063] Take a 100mL round-bottom flask, add 2-chloropyrimidine-5-carboxylic acid (6.30mmol), dichloromethane (20mL) and DMF (0.2mL), then slowly add oxalyl chloride (9.45mmol) dropwise at 0°C, restore to room temperature after the addition is complete and continue to react for 2h, concentrate the reaction system to remove the solvent to obtain 2-chloropyrimidine-5-carbonyl chloride, take another 100mL round-bottom flask, add 2-methyl-1-butanol (6.3mmol), dichloromethane (20mL), DMAP (1.26mmol) and triethylamine (9.45mmol), then slowly add a dichloromethane solution (10mL) of 2-chloropyrimidine-5-carbonyl chloride dropwise at 0°C, restore to room temperature after the addition is complete and continue to react for 2h, quench the reaction system with water, extract three times with dichloromethane, combine the organic phases, dry, concentrate the solution and separate by silica gel column chromatography to obtain product A (yield 81%).

[0064] (Preparation of B)

[0065] Compound A (5mmol), 4-bromo-2-methoxyphenylboronic acid (6mmol), K2CO3 (10mmol), Pd(PPh3)4 (0.25mmol) were added to a 250mL thick-walled reaction tube, Dioxane (40mL) and H2O (10mL) were added, and the reaction system was reacted at 80°C for 12h. After the reaction was completed, the system was concentrated and separated by silica gel column chromatography to obtain product B (yield 49%).

[0066] (Preparation of C)

[0067] Take a 250mL round-bottom flask and add 6-bromo-2-naphthylamine (12mmol), paraformaldehyde (65mmol), solvent THF (50mL) and sodium cyanoborohydride (65mol) respectively. Add glacial acetic acid (65mmol) dropwise to the resulting mixture and heat it to 50°C and stir at this temperature for 18 hours. The reaction mixture is cooled to room temperature and then distributed between saturated sodium bicarbonate aqueous solution (100mL) and ether (40mL). Separate the layers and extract the aqueous layer with ether (2×40mL). Wash the combined organic layers with water (2×60mL) and saturated sodium chloride aqueous solution (3×40mL) in turn. Dry the combined organic layers with anhydrous sodium sulfate and concentrate the dry solution. The resulting residue is purified by flash column chromatography to obtain product C (yield 73%).

[0068] (Preparation of D)

[0069] In a 100 mL reaction bottle, under nitrogen atmosphere, intermediate C (5 mmol), (Bpin)2 (7.5 mmol), Pd(dppf)Cl2 (0.25 mmol), KOAc (15 mmol) were dissolved in a stirred suspension of dioxane (25 mL). The suspension was heated to 90 ° C in an oil bath and stirred overnight. After the reaction was complete, water (25 mL) was added and the mixture was extracted with DCM (20 mL x 4). The solvent was removed under reduced pressure. The residue was separated by silica gel column chromatography to obtain product D (yield 81%).

[0070] (Preparation of E)

[0071] Compound B (2mmol), compound D (2.4mmol), K2CO3 (4mmol), and Pd(PPh3)4 (0.1mmol) were added to a 100mL thick-walled reaction tube, and Dioxane (20mL) and H2O (5mL) were added. After the reaction was completed, the system was concentrated and separated by silica gel column chromatography to obtain product E (yield 65%).

[0072] (Preparation of F)

[0073] Compound E (1 mmol) was dissolved in DCM (10 mL), and then 2 M BBr3 (4 mmol) solution was slowly added dropwise under ice bath, and the reaction was allowed to proceed for about 5 h. After the reaction was complete, methanol was added to the system under ice bath to quench the reaction, and the mixture was stirred for 1 h. The system was then spin dried and separated by silica gel column chromatography to obtain product D (yield 45%).

[0074] Synthesis example 3

[0075]

[0076] (Preparation of A)

[0077] A 100 mL round-bottom flask was taken, and 2-chloropyrimidine-5-carboxylic acid (6.30 mmol), dichloromethane (20 mL) and DMF (0.2 mL) were added respectively, and then oxalyl chloride (9.45 mmol) was slowly added dropwise at 0°C. After the addition was completed, the reaction was continued at room temperature for 2 h. The reaction system was concentrated to remove the solvent to obtain 2-chloropyrimidine-5-carbonyl chloride. Another 100 mL round-bottom flask was taken, and 2-methyl-4-n-butylphenol (6.3 mmol), dichloromethane (20 mL), DMAP (1.26 mmol) and triethylamine (9.45 mmol) were added respectively. Then a dichloromethane solution (10 mL) of 2-chloropyrimidine-5-carbonyl chloride was slowly added dropwise at 0°C. After the addition was completed, the reaction was continued at room temperature for 2 h. The reaction system was quenched with water, extracted three times with dichloromethane, the organic phases were combined, dried, and the solution was concentrated and separated by silica gel column chromatography to obtain product A (yield 63%).

[0078] (Preparation of B)

[0079] Compound A (5mmol), 4-bromo-2-methoxyphenylboronic acid (6mmol), K2CO3 (10mmol), Pd(PPh3)4 (0.25mmol) were added to a 250mL thick-walled reaction tube, Dioxane (40mL) and H2O (10mL) were added, and the reaction system was reacted at 80°C for 12h. After the reaction was completed, the system was concentrated and separated by silica gel column chromatography to obtain product B (yield 37%).

[0080] (Preparation of C)

[0081] Compound B (2mmol), p-dimethylaminophenylboronic acid (2.4mmol), K2CO3 (4mmol), and Pd(PPh3)4 (0.1mmol) were added to a 100mL thick-walled reaction tube, and Dioxane (20mL) and H2O (5mL) were added. After the reaction was completed, the system was concentrated and separated by silica gel column chromatography to obtain product C (yield 65%).

[0082] (Preparation of D)

[0083] Compound C (1 mmol) was dissolved in DCM (10 mL), and then 2 M BBr3 (4 mmol) solution was slowly added dropwise under ice bath, and the reaction was allowed to proceed for about 5 h. After the reaction was complete, methanol was added to the system under ice bath to quench the reaction, and the mixture was stirred for 1 h. The system was then spin dried and separated by silica gel column chromatography to obtain product D (yield 55%).

[0084] Synthesis example 4

[0085]

[0086] (Preparation of A)

[0087] A 100 mL round-bottom flask was taken, and 2-chloropyrimidine-5-carboxylic acid (6.30 mmol), dichloromethane (20 mL) and DMF (0.2 mL) were added respectively, and then oxalyl chloride (9.45 mmol) was slowly added dropwise at 0°C. After the addition was completed, the reaction was continued at room temperature for 2 h. The reaction system was concentrated to remove the solvent to obtain 2-chloropyrimidine-5-carbonyl chloride. Another 100 mL round-bottom flask was taken, and 1-butanol (6.3 mmol), dichloromethane (20 mL), DMAP (1.26 mmol) and triethylamine (9.45 mmol) were added respectively. Then a dichloromethane solution (10 mL) of 2-chloropyrimidine-5-carbonyl chloride was slowly added dropwise at 0°C. After the addition was completed, the reaction was continued at room temperature for 2 h. The reaction system was quenched with water, extracted three times with dichloromethane, the organic phases were combined, dried, and the solution was concentrated and separated by silica gel column chromatography to obtain product A (yield 83%).

[0088] (Preparation of B)

[0089] Compound A (5mmol), 4-bromo-2-methoxyphenylboronic acid (6mmol), K2CO3 (10mmol), Pd(PPh3)4 (0.25mmol) were added to a 250mL thick-walled reaction tube, Dioxane (40mL) and H2O (10mL) were added, and the reaction system was reacted at 80°C for 12h. After the reaction was completed, the system was concentrated and separated by silica gel column chromatography to obtain product B (yield 52%).

[0090] (Preparation of C)

[0091] Under nitrogen atmosphere, N-methyl-p-bromoaniline (5mmol) and 4-n-hexyl iodobenzene (7.5mmol) were added to a stirred suspension of Pd(dba)2 (0.25mmol), rac-BINAP (0.5mmol) and Cs2CO3 (10.0mmol) in toluene (20mL) at room temperature. The suspension was heated to 80°C in an oil bath and stirred overnight. Water (20mL) was added and the mixture was extracted with DCM (4 times 20mL). The combined organic layers were washed with brine, dried, concentrated to remove the solvent, and the residue was separated by silica gel column chromatography to obtain product C (yield 51%).

[0092] (Preparation of D)

[0093] In a 100 mL reaction bottle, under nitrogen atmosphere, intermediate C (5 mmol), (Bpin)2 (7.5 mmol), Pd(dppf)Cl2 (0.25 mmol), KOAc (15 mmol) were dissolved in a stirred suspension of dioxane (25 mL). The suspension was heated to 90°C in an oil bath and stirred overnight. After the reaction was complete, water (25 mL) was added and the mixture was extracted with DCM (20 mL×4). The solvent was removed under reduced pressure. The residue was separated by silica gel column chromatography to obtain product D (yield 73%).

[0094] (Preparation of E)

[0095] Compound B (2mmol), compound D (2.4mmol), K2CO3 (4mmol), and Pd(PPh3)4 (0.1mmol) were added to a 100mL thick-walled reaction tube, and Dioxane (20mL) and H2O (5mL) were added. After the reaction was completed, the system was concentrated and separated by silica gel column chromatography to obtain product E (yield 58%).

[0096] (Preparation of F)

[0097] Compound E (1 mmol) was dissolved in DCM (10 mL), and then 2 M BBr3 (4 mmol) solution was slowly added dropwise in an ice bath. The reaction was allowed to react for about 5 h. After the reaction was complete, methanol was added to the system in an ice bath to quench the reaction. The mixture was stirred for 1 h, and then the system was spin-dried and separated by silica gel column chromatography to obtain product F (yield 49%).

[0098] Synthesis example 5

[0099]

[0100] (Preparation of A)

[0101] A 100 mL round-bottom flask was taken, and 2-chloropyrimidine-5-carboxylic acid (6.30 mmol), dichloromethane (20 mL) and DMF (0.2 mL) were added respectively, and then oxalyl chloride (9.45 mmol) was slowly added dropwise at 0°C. After the addition was completed, the reaction was continued at room temperature for 2 h. The reaction system was concentrated to remove the solvent to obtain 2-chloropyrimidine-5-carbonyl chloride. Another 100 mL round-bottom flask was taken, and 2-methyl-4-n-hexylphenol (6.3 mmol), dichloromethane (20 mL), DMAP (1.26 mmol) and triethylamine (9.45 mmol) were added respectively. Then a dichloromethane solution (10 mL) of 2-chloropyrimidine-5-carbonyl chloride was slowly added dropwise at 0°C. After the addition was completed, the reaction was continued at room temperature for 2 h. The reaction system was quenched with water, extracted three times with dichloromethane, the organic phases were combined, dried, and the solution was concentrated and separated by silica gel column chromatography to obtain product A (yield 66%).

[0102] (Preparation of B)

[0103] Compound A (5mmol), 4-bromo-2-methoxyphenylboronic acid (6mmol), K2CO3 (10mmol), Pd(PPh3)4 (0.25mmol) were added to a 250mL thick-walled reaction tube, Dioxane (40mL) and H2O (10mL) were added, and the reaction system was reacted at 80°C for 12h. After the reaction was completed, the system was concentrated and separated by silica gel column chromatography to obtain product B (yield 42%).

[0104] (Preparation of C)

[0105] In a 100 mL reaction bottle, N,N-diethyl-p-bromoaniline (5 mmol), (Bpin)2 (7.5 mmol), Pd(dppf)Cl2 (0.25 mmol), and KOAc (15 mmol) were dissolved in a stirred suspension of dioxane (25 mL) under a nitrogen atmosphere. The suspension was heated to 90°C in an oil bath and stirred overnight. After the reaction was complete, water (25 mL) was added and the mixture was extracted with DCM (20 mL×4). The solvent was removed under reduced pressure. The residue was separated by silica gel column chromatography to obtain product C (yield 82%).

[0106] (Preparation of D)

[0107] Compound C (2mmol), p-dimethylaminophenylboronic acid (2.4mmol), K2CO3 (4mmol), and Pd(PPh3)4 (0.1mmol) were added to a 100mL thick-walled reaction tube, and Dioxane (20mL) and H2O (5mL) were added. After the reaction was completed, the system was concentrated and separated by silica gel column chromatography to obtain product D (yield 68%).

[0108] (Preparation of E)

[0109] Compound D (1 mmol) was dissolved in DCM (10 mL), and then 2 M BBr3 (4 mmol) solution was slowly added dropwise in an ice bath. The reaction was allowed to react for about 5 h. After the reaction was complete, methanol was added to the system in an ice bath to quench the reaction. The mixture was stirred for 1 h, and then the system was spin-dried and separated by silica gel column chromatography to obtain product E (yield 37%).

[0110] Synthesis example 6

[0111]

[0112] (Preparation of A)

[0113] A 100 mL round-bottom flask was taken, and 2-chloropyrimidine-5-carboxylic acid (6.30 mmol), dichloromethane (20 mL) and DMF (0.2 mL) were added respectively, and then oxalyl chloride (9.45 mmol) was slowly added dropwise at 0°C. After the addition was completed, the reaction was continued at room temperature for 2 h. The reaction system was concentrated to remove the solvent to obtain 2-chloropyrimidine-5-carbonyl chloride. Another 100 mL round-bottom flask was taken, and 2-methyl-4-n-hexylphenol (6.3 mmol), dichloromethane (20 mL), DMAP (1.26 mmol) and triethylamine (9.45 mmol) were added respectively. Then a dichloromethane solution (10 mL) of 2-chloropyrimidine-5-carbonyl chloride was slowly added dropwise at 0°C. After the addition was completed, the reaction was continued at room temperature for 2 h. The reaction system was quenched with water, extracted three times with dichloromethane, the organic phases were combined, dried, and the solution was concentrated and separated by silica gel column chromatography to obtain product A (yield 66%).

[0114] (Preparation of B)

[0115] Compound A (5mmol), 4-bromo-2-methoxyphenylboronic acid (6mmol), K2CO3 (10mmol), Pd(PPh3)4 (0.25mmol) were added to a 250mL thick-walled reaction tube, Dioxane (40mL) and H2O (10mL) were added, and the reaction system was reacted at 80°C for 12h. After the reaction was completed, the system was concentrated and separated by silica gel column chromatography to obtain product B (yield 42%).

[0116] (Preparation of C)

[0117] In a 250 mL round-bottom flask, N-methyl-p-bromoaniline (20.0 mmol), DMF (30 mL), potassium carbonate (50.0 mmol) and 1-bromohexane (24.0 mmol) were added and stirred at 60° C. for 4 hours. The reaction mixture was quenched with ice water, extracted with ethyl acetate, and the solvent was removed under reduced pressure. The residue was separated by silica gel column chromatography to obtain product A (yield 73%).

[0118] (Preparation of D)

[0119] In a 100 mL reaction bottle, compound C (5 mmol), (Bpin)2 (7.5 mmol), Pd(dppf)Cl2 (0.25 mmol), and KOAc (15 mmol) were dissolved in a stirred suspension of dioxane (25 mL) under a nitrogen atmosphere. The suspension was heated to 90°C in an oil bath and stirred overnight. After the reaction was complete, water (25 mL) was added and the mixture was extracted with DCM (20 mL×4). The solvent was removed under reduced pressure. The residue was separated by silica gel column chromatography to obtain product D (yield 80%).

[0120] (Preparation of E)

[0121] Compound B (2mmol), compound D (2.4mmol), K2CO3 (4mmol), and Pd(PPh3)4 (0.1mmol) were added to a 100mL thick-walled reaction tube, and Dioxane (20mL) and H2O (5mL) were added. After the reaction was completed, the system was concentrated and separated by silica gel column chromatography to obtain product E (yield 59%).

[0122] (Preparation of F)

[0123] Compound E (1 mmol) was dissolved in DCM (10 mL), and then 2 M BBr3 (4 mmol) solution was slowly added dropwise in an ice bath. The reaction was allowed to react for about 5 h. After the reaction was complete, methanol was added to the system in an ice bath to quench the reaction. The mixture was stirred for 1 h, and then the system was spin-dried and separated by silica gel column chromatography to obtain product F (yield 44%).

[0124] Synthesis Example 7

[0125]

[0126] (Preparation of A)

[0127] In a 250mL round-bottom flask, 2-propanol (20mL) and 5% Pd / C (0.28mmol) were added respectively. Ammonium formate (13.8mmol) dissolved in water (2mL) was transferred to the flask. The reaction mixture was stirred for 1 minute to activate Pd / C. Next, p-aminophenol (2.8mmol) and 1-valeraldehyde (3.2mmol) were added, and the reaction mixture was stirred at room temperature for 2h. After the reaction was completed, the Pd / C catalyst was filtered out on diatomaceous earth and the solvent was removed. The residue was separated by silica gel column chromatography to obtain product A (yield 67%).

[0128] (Preparation of B)

[0129] Take a 100mL round-bottom flask, add 2-chloropyrimidine-5-carboxylic acid (6.30mmol), dichloromethane (20mL) and DMF (0.2mL), then slowly add oxalyl chloride (9.45mmol) dropwise at 0°C, restore to room temperature after the addition is complete and continue to react for 2h, concentrate the reaction system to remove the solvent to obtain 2-chloropyrimidine-5-carbonyl chloride, take another 100mL round-bottom flask, add compound A (6.3mmol), DMF (20mL), potassium carbonate (1.26mmol), respectively, then slowly add a dichloromethane solution (10mL) of 2-chloropyrimidine-5-carbonyl chloride dropwise at 0°C, restore to room temperature after the addition is complete and continue to react for 2h, quench the reaction system with water, extract three times with dichloromethane, combine the organic phases, dry, concentrate the solution and separate by silica gel column chromatography to obtain product B (yield 41%).

[0130] (Preparation of C)

[0131] Compound B (5mmol), 4-bromo-2-methoxyphenylboronic acid (6mmol), K2CO3 (10mmol), Pd(PPh3)4 (0.25mmol) were added to a 250mL thick-walled reaction tube, Dioxane (40mL) and H2O (10mL) were added, and the reaction system was reacted at 80°C for 12h. After the reaction was completed, the system was concentrated and separated by silica gel column chromatography to obtain product C (yield 57%).

[0132] (Preparation of D)

[0133] Compound C (2mmol), p-dimethylaminophenylboronic acid (2.4mmol), K2CO3 (4mmol), and Pd(PPh3)4 (0.1mmol) were added to a 100mL thick-walled reaction tube, and Dioxane (20mL) and H2O (5mL) were added. After the reaction was completed, the system was concentrated and separated by silica gel column chromatography to obtain product D (yield 61%).

[0134] (Preparation of E)

[0135] Compound D (1 mmol) was dissolved in DCM (10 mL), and then 2 M BBr3 (4 mmol) solution was slowly added dropwise under ice bath, and the reaction was allowed to proceed for about 5 h. After the reaction was complete, methanol was added to the system under ice bath to quench the reaction, and the mixture was stirred for 1 h. The system was then spin-dried and separated by silica gel column chromatography to obtain product E (yield 51%).

[0136] 2. Performance Test Implementation

[0137] The yellow dichroic dye prepared according to the above preparation method is shown in Table 1 below.

[0138] Table 1 Structure of yellow dichroic dyes

[0139]

[0140] The performance data of the yellow dichroic dye was tested. The specific test method was as follows: the test box used for the dye performance test was a 9μm transparent space powder as a spacing layer, supported by a glass plate of an anti-parallel friction orientation layer (polyimide) and a transparent conductive layer (ITO); the dye liquid crystal used for the test was the dye dissolved in a certain proportion in a mother liquid crystal of XHLC-0321 (Yantai Xianhua Technology Group).

[0141] The specific structural composition of the mother liquid crystal XHLC-0321 is shown in Table 2 below.

[0142] Table 2 Composition and physical properties of parent liquid crystal XHLC-0321

[0143]

[0144] According to the test ratio (the mass ratio of the monochrome dye added to the liquid crystal matrix is ​​1% when testing the dye dichroism; the mass ratio of the monochrome dye added to the liquid crystal matrix is ​​5% when testing the dye contrast), the monochrome dye is added to the liquid crystal matrix and placed on an electromagnetic heating stirrer (08-2, Jiangsu Jiamei Instrument Manufacturing Co., Ltd.) at 120°C to completely dissolve it. After cooling to room temperature, a vacuum crystal filling machine is used to pour the prepared dye liquid crystal into the above test box.

[0145] Dye dichroism D test: Use DMS505 (Instruments Systems GmbH, Germany) and add a polarizer to its light source. Perform two tests, one with the polarizer adjusted to be parallel to the rubbing direction of the test box, and one with the polarizer perpendicular to the rubbing direction of the test box. Record the maximum absorbance A∥ and A⊥ of the two test results respectively, and the dichroic ratio D = A∥ / A⊥.

[0146] Dye contrast CR test: Use DMS505 (Instruments Systems GmbH, Germany) and no polarizer at the light source. Perform two tests, one to test the transmittance without power, and one to test with 10V square wave AC on the test box. Record the transmittance T of the two test results respectively. 0V and T 10V , contrast ratio CR = T 0V / T 10V Then the transmittance T' was tested at 150℃ without power for 10 hours. 0V , the transmittance T' is tested at 150℃ with 10V AC for 10 hours 10V , contrast CR′=T′ 0V / T′ 10V The specific test results are shown in Table 3. Figure 1 This is the spectrum diagram of HSYD01. Figure 1 It can be seen that the transmittance of the dye liquid crystal in the dark and bright states is within the wavelength range of 380-800nm. The dark state is when a voltage of 10V is applied, and the transmittance is 87.0%. The bright state is when no voltage is applied, and the transmittance is 89.6%. The contrast ratio T is the ratio of the transmittance of the bright state to the dark state. The contrast ratio CR of HSYD01 is 1.03. Figure 2 This is the high temperature aging spectrum of HSYD01. Figure 2It can be seen that the transmittance of the dye liquid crystal in the dark state and the light state at 150°C for 10 hours in the wavelength range of 380-800nm ​​is 87.1% in the dark state when 10V voltage is applied, 150°C, and 10 hours, and 89.5% in the light state when no voltage is applied, 150°C, and 10 hours. The contrast ratio T is the ratio of the transmittance of the light state to the dark state, and the contrast ratio CR′ of HSYD01 is 1.03. In terms of the transmittance at 450nm, the transmittance of the light state and the dark state of HSYD01 in Example 1 is 0.33 and 0.16 respectively, while the transmittance of the light state and the dark state of 37Y in Comparative Example 1 is 0.55 and 0.31 respectively, indicating that HSYD01 has a stronger absorption intensity, resulting in a decrease in transmittance. These results are consistent with the UV-Vis absorption spectra of the two dyes in toluene ( Figure 3 ). Figure 3 In the wavelength range of 380-450nm, HSYD01 has stronger absorption than 37Y. The stronger absorption intensity is mainly derived from the linear connection of multiple aromatic rings in the general structure and the color enhancement effect of the amine group connected to the L group.

[0147] Table 3 Yellow dichroic dye performance test results

[0148]

[0149]

[0150] It can be seen from the above data that the yellow dichroic dye of the present invention has excellent solubility and thermal stability, and the absorption intensity and dichroic comparison 37Y within the main absorption wavelength range of yellow are further improved, thereby achieving higher color contrast and clearer display effect.

[0151] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are exhaustively listed. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0152] For those skilled in the art, several modifications and improvements may be made without departing from the concept of the present invention, all of which belong to the protection scope of the present invention. The protection scope of the present invention shall be based on the attached claims.

Claims

1. A yellow dichroic dye, characterized in that The general structural formula of the yellow dichroic dye is selected from the following formula (I): In formula (I), R1 and R2 are independently selected from H, C1-C20 alkyl, C6-C12 cycloalkyl, C1-C20 alkoxy, C6-C12 cycloalkyloxy, C1-C20 alkylamino, substituted or unsubstituted C6-C50 aryl, substituted or unsubstituted C2-C50 heteroaryl, allyl, acyl, amino, C2-C10 acylamino, C2-C10 acyloxy; the substituents in R1 and R2 are selected from hydroxyl, C1-C12 alkyl, C1-C20 alkoxy or carboxyl; R3 is selected from H, substituted or unsubstituted C1-C12 alkyl, C2-C6 alkenyl, substituted or unsubstituted C1-C18 alkoxy, C1-C18 alkylamino, C5-C12 cycloalkyloxy, C2-C18 alkenyloxy, -C≡N, C1-C4 haloalkyl, sulfo, acyl, C2-C18 acylamino, C2-C18 acyloxy, substituted or unsubstituted C6-C50 aryl, substituted or unsubstituted C2-C50 heteroaryl; the substituent in R3 is selected from C1-C18 alkyl, C1-C18 alkoxy or halogen; The heteroatom of the heteroaryl group is oxygen, nitrogen or sulfur; X1 is hydrogen, nitrogen, sulfur or halogen; L is selected from phenylene or naphthylene.

2. A yellow dichroic dye according to claim 1, characterized in that: R1 and R2 are independently selected from C1~C20 alkyl, cyclohexyl, C1~C20 alkoxy, C1~C20 alkylamino, cyclohexyloxy, allyl, amino, acyl, C2~C10 acylamino, C2~C10 acyloxy; substituted or unsubstituted C6~C30 aryl, substituted or unsubstituted C2~C30 heteroaryl.

3. A yellow dichroic dye according to claim 1, characterized in that: R1 and R2 are independently selected from C1-C20 alkyl, substituted or unsubstituted C6-C18 aryl, substituted or unsubstituted C2-C18 heteroaryl.

4. A yellow dichroic dye according to claim 1, characterized in that: R1 and R2 are independently selected from the following structures:

5. A yellow dichroic dye according to claim 1, characterized in that: R3 is selected from C1~C8 alkyl, allyl, C1~C4 alkoxy, C1~C4 alkylamino, C1~C18 alkyl substituted by C1~C4 alkoxy or halogen, C1~C4 alkoxy substituted by C1~C4 alkoxy or halogen, acyl, C2~C10 acylamino, C2~C10 acyloxy, substituted or unsubstituted C6~C30 aryl, substituted or unsubstituted C2~C30 heteroaryl.

6. A yellow dichroic dye according to claim 1, characterized in that: R3 is selected from C1-C8 alkyl; substituted or unsubstituted C6-C18 aryl, substituted or unsubstituted C2-C18 heteroaryl.

7. A yellow dichroic dye according to claim 1, characterized in that: R3 is selected from any one of the following structures:

8. A yellow dichroic dye according to claim 1, characterized in that: X1 is hydrogen or nitrogen; The L is selected from any one of the following structures:

9. A yellow dichroic dye according to claim 1, wherein the yellow dichroic dye is selected from any one of the following structural formulas:

10. Use of a yellow dichroic dye according to any one of claims 1 to 9, characterized in that: The yellow dichroic dye is combined with a liquid crystal matrix to form a guest-host liquid crystal composition which is applied in a liquid crystal display device.

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