A benzodithiazole organic dye, a preparation method and application thereof, and an electrowetting display ink

Abstract

The application discloses a benzobisthiazole organic dye, a preparation method and application thereof, and an electrowetting display ink. The benzobisthiazole (BBT)-based organic dye provided by the application can realize the absorption of a wave band above 700 nm through the mutual cooperation between a benzobisthiazole main ring structure and a branched chain structure, obtain an organic dye with a cyan color phase, and meanwhile, the light stability and solubility of the dye are improved. Moreover, raw materials for a synthesis process are easy to obtain, reaction conditions are mild, functional group tolerance is good, and a substrate is not sensitive to water and air. The ink prepared by using the organic dye has extremely high solubility and a molar extinction coefficient, and has bright color and high saturation. An electrowetting device made of the above ink has good electrowetting performance, low switching voltage, fast response time, and no backflow phenomenon under a constant voltage, which proves that the organic dye has great application prospect in the field of electrowetting display.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electrowetting display, in particular to a benzodithiazole organic dye, a preparation method and application thereof, and an electrowetting display ink. BACKGROUND

[0002] Electrofluide display (EFD) is a display prototype based on the principle of electrowetting display, including dye, polar liquid and hydrophobic layer. The principle is to control the surface properties of the hydrophobic layer by voltage, and then change the contact angle of the ink layer on the hydrophobic layer, so as to obtain the effect of display image. Specifically, when no voltage is applied, the ink wets the hydrophobic layer uniformly, forming a colored pixel point; when voltage is applied, the interfacial tension between the dye-polar-liquid hydrophobic layer changes, and the ink is compressed, forming a transparent or substrate color pixel point.

[0003] The electrowetting display ink is a special material for displaying color of the electrowetting display. The solubility in non-polar solvent, color saturation and color strength of the dye in the electrowetting display ink are closely related to the color effect of the electrowetting display. In the electrowetting display, the commonly used organic dyes include anthraquinone organic dyes and azo organic dyes. Most of the anthraquinone organic dyes have attracted great attention due to their low polarity and excellent light resistance, but the color strength of the anthraquinone organic dyes is low. The azo organic dyes make up for the shortcomings of the anthraquinone organic dyes, and have the advantage of high color strength. However, most of the azo organic dyes have poor light stability, which is difficult to meet the application requirements of the electrowetting display device in outdoor environment. Moreover, the absorption of these two types of dyes is below 700 nm.

[0004] Therefore, it is of great significance to solve the problems of the existing electrowetting display dye, provide a dye structure with absorption above 700 nm, and obtain a pure cyan color in the electrowetting display technology, as well as an organic dye with high light stability, high non-polar solubility and high color strength. SUMMARY

[0005] The present application aims to solve at least one of the technical problems existing in the prior art. To this end, the present application provides a benzodithiazole organic dye, a preparation method and application thereof, and an electrowetting display ink, which aims to solve the problem that there is no organic dye with absorption above 700 nm and high light stability, high non-polar solubility and high color strength in the current electrowetting display.

[0006] In a first aspect of the present application, a benzodithiazole organic dye is provided, and the structure general formula of the benzodithiazole organic dye is shown as formula (I):

[0007]

[0008] wherein R1is, at each occurrence, independently selected from substituted or unsubstituted alkyl, substituted or unsubstituted oxaalkyl, substituted or unsubstituted alkylphenyl;

[0009] R2is, at each occurrence, independently selected from H atom, halogen, substituted or unsubstituted alkyl, substituted or unsubstituted alicyclyl, phenyl, substituted or unsubstituted alkylphenyl, substituted or unsubstituted oxaalkyl, substituted or unsubstituted alkylthiophenyl, substituted or unsubstituted alkylsilyl, substituted or unsubstituted alkylalkynyl.

[0010] The benzo bis-thiadiazole organic dye according to the embodiments of the present application has at least the following beneficial effects: the benzo bis-thiadiazole (BBT) based organic dye provided by the present application has a benzo bis-thiadiazole main ring structure and branched chain structures such as alkyl, phenyl, alkylphenyl, alkylthiophenyl, etc. The benzo bis-thiadiazole organic conjugated molecule has strong coplanarity, electron-withdrawing ability, high oxidation potential and good air stability. The present application takes 4,8-bis(2-thienyl)-2lambda 4 δ 2 A series of benzo bis-thiadiazole compounds are synthesized based on the parent 4,8-bis(2-thienyl)-2lambda -benzo[1,2-c:4,5-c']bis[1,2,5]thiadiazo (BBT). Through the mutual cooperation between the benzo bis-thiadiazole main ring structure and the branched chain structure, the absorption of the wave band above 700 nm can be realized, the organic dye with cyan color phase can be obtained, and the light stability and solubility of the organic dye are also improved. Furthermore, the organic dye has good solubility in non-polar organic solvents. The ink prepared by using the benzo bis-thiadiazole organic dye has pure color and high molar absorption coefficient, and has great application prospect in the field of electrowetting display.

[0011] In some embodiments of the present application, R1is selected from substituted or unsubstituted C4-C20 alkyl.

[0012] In some preferred embodiments of the present application, R1is selected from substituted or unsubstituted C13-C20 alkyl.

[0013] In some more preferred embodiments of the present application, R1is selected from substituted or unsubstituted C15-C20 alkyl.

[0014] In some embodiments of the present application, R1is selected from substituted or unsubstituted C4-C20 oxaalkyl.

[0015] In some preferred embodiments of the present application, R1is selected from substituted or unsubstituted C8-C15 oxaalkyl.

[0016] In some more preferred embodiments of the application, said R1 is selected from 3-(2- ethylhexyloxy)propyl.

[0017] In some embodiments of the application, said R1 is selected from substituted or unsubstituted C7-C20 alkylphenyl.

[0018] In some preferred embodiments of the application, said R1 is selected from substituted or unsubstituted C7-C13 alkylphenyl.

[0019] In some more preferred embodiments of the application, said R1 is selected from substituted or unsubstituted C7-C10 alkylphenyl.

[0020] In some embodiments of the application, said R2 is selected from halogen. Preferably, said R2 is selected from Br, CI, I.

[0021] In some embodiments of the application, said R2 is selected from substituted or unsubstituted C4-C20 alkyl.

[0022] In some preferred embodiments of the application, said R2 is selected from substituted or unsubstituted C13-C20 alkyl.

[0023] In some more preferred embodiments of the application, said R2 is selected from substituted or unsubstituted C15-C20 alkyl.

[0024] In some embodiments of the application, said R2 is selected from substituted or unsubstituted C4-C20 alicyclyl.

[0025] In some preferred embodiments of the application, said R2 is selected from substituted or unsubstituted C4-C10 alicyclyl.

[0026] In some more preferred embodiments of the application, said R2 is selected from substituted or unsubstituted C5 alicyclyl.

[0027] In some embodiments of the application, said R2 is selected from substituted or unsubstituted C7-C20 alkylphenyl.

[0028] In some preferred embodiments of the application, said R2 is selected from substituted or unsubstituted C7-C10 alkylphenyl In some embodiments of the application, said R2 is selected from substituted or unsubstituted C4-C20 oxaalkyl.

[0029] In some preferred embodiments of the application, said R2 is selected from substituted or unsubstituted C5-C15 oxaalkyl

[0030] In some more preferred embodiments of the application, said R2 is selected from 3-(2- ethylhexyloxy)propyl.

[0031] In some embodiments of the application, R2is selected from substituted or unsubstituted C4-C20alkylthiophenyl.

[0032] In some preferred embodiments of the application, R2is selected from 3-(2- octyldodecyl)thiophene.

[0033] In some embodiments of the application, R2is selected from substituted or unsubstituted C4-C20alkylsilyl.

[0034] In some preferred embodiments of the application, R2is selected from triisopropylsilyl.

[0035] In some embodiments of the application, R2is selected from substituted or unsubstituted C4-C20alkylalkynyl.

[0036] In some preferred embodiments of the application, R2is selected from 5- ethynylundecane.

[0037] In some embodiments of the application, R1is selected from butyl, cyclobutyl, pentyl, cyclopentylidene, n-hexyl, n-heptyl, n-octyl, iso-octyl, 2- ethylhexyl, nonyl, n-decyl, n-undecyl, n-dodecyl, n-tridecyl, n-tetradecyl, n- pentadecyl, n-hexadecyl, n-heptadecyl, n-octadecyl, n-nonadecyl, n- eicosyl, 2-nonyldecyl, 2-pentylhexyl, 2-heptyloctyl, 2-octyldodecyl.

[0038] In some embodiments of the application, R2is selected from butyl, cyclobutyl, pentyl, cyclopentylidene, n-hexyl, n-heptyl, n-octyl, iso-octyl, 2- ethylhexyl, nonyl, n-decyl, n-undecyl, n-dodecyl, n-tridecyl, n-tetradecyl, n- pentadecyl, n-hexadecyl, n-heptadecyl, n-octadecyl, n-nonadecyl, n- eicosyl, 2-nonyldecyl, 2-pentylhexyl, 2-heptyloctyl, 2-octyldodecyl, 3-(2- ethylhexyloxy)propyl, phenyl, methylphenyl, ethylphenyl, propylphenyl, butylphenyl, pentylphenyl, hexylphenyl, heptylphenyl, octylphenyl, nonylphenyl, decylphenyl, undecylphenyl, dodecylphenyl, tridecylphenyl, tetradecylphenyl.

[0039] In the present application, "substituted or unsubstituted" means that the group can or can not be further substituted with one or more groups selected from alkyl, alkenyl, alkynyl, aryl, halogen, haloalkyl, haloalkenyl, haloalkynyl, haloaryl, hydroxy, alkoxy, alkenoxy, aryloxy, benzyloxy, haloalkoxy, haloalkenoxy, haloaryloxy, nitro, nitroalkyl, nitroalkenyl, nitroalkynyl, nitroaryl, nitroheterocyclyl, amino, alkylamino, dialkylamino, alkenylamino, alkynylamino, arylamino, diarylamino, phenylamino, diphenylamino, benzylamino, dibenzylamino, hydrazino, acyl, acylamino, diacylamino, acyloxy, heterocyclyl, heterocyclyloxy, heterocyclylamino, haloheterocyclyl, carboxyl ester, carboxyl.

[0040] In some embodiments of the present application, R1 is selected from substituted or unsubstituted alkyl, substituted or unsubstituted oxaalkyl, substituted or unsubstituted alkylphenyl, wherein the substituents of the above-mentioned alkyl, oxaalkyl, alkylphenyl are independently selected from alkyl, alkenyl, alkynyl, aryl, halogen, haloalkyl, haloalkenyl, haloalkynyl, haloaryl, hydroxy, alkoxy, alkenoxy, aryloxy, benzyloxy, haloalkoxy, haloalkenoxy, haloaryloxy, nitro, nitroalkyl, nitroalkenyl, nitroalkynyl, nitroaryl, nitroheterocyclyl, amino, alkylamino, dialkylamino, alkenylamino, alkynylamino, arylamino, diarylamino, phenylamino, diphenylamino, benzylamino, dibenzylamino, hydrazino, acyl, acylamino, diacylamino, acyloxy, heterocyclyl, heterocyclyloxy, heterocyclylamino, haloheterocyclyl, carboxyl ester, carboxyl.

[0041] In some embodiments of the present application, R2 is selected from substituted or unsubstituted alkyl, substituted or unsubstituted alicyclyl, substituted or unsubstituted alkylphenyl, substituted or unsubstituted oxaalkyl, substituted or unsubstituted alkylthiophenyl, substituted or unsubstituted alkylalkynyl, wherein the substituents of the above-mentioned alkyl, alicyclyl, alkylphenyl, oxaalkyl, alkylthiophenyl, alkylalkynyl are independently selected from alkyl, alkenyl, alkynyl, aryl, halogen, haloalkyl, haloalkenyl, haloalkynyl, haloaryl, hydroxy, alkoxy, alkenoxy, aryloxy, benzyloxy, haloalkoxy, haloalkenoxy, haloaryloxy, nitro, nitroalkyl, nitroalkenyl, nitroalkynyl, nitroaryl, nitroheterocyclyl, amino, alkylamino, dialkylamino, alkenylamino, alkynylamino, arylamino, diarylamino, phenylamino, diphenylamino, benzylamino, dibenzylamino, hydrazino, acyl, acylamino, diacylamino, acyloxy, heterocyclyl, heterocyclyloxy, heterocyclylamino, haloheterocyclyl, carboxyl ester, carboxyl.

[0042] In the related art, the molar absorption coefficient of the anthraquinone type electrowetting display dye is generally low (~1.5 x 104 L·mol -1 ·cm -1 ), it is difficult to meet the requirements of high color saturation, and lack of light color. The present application first develops a series of organic dyes applied to the ink of the electrowetting device based on the benzobisthiazole (BBT) skeleton. The structure of the organic dyes has pure color and high color saturation, and the molar absorption coefficient is high (>1.5×10 4 L·mol -1 ·cm -1 ), and the electrowetting device prepared has the characteristics of easy driving, large aperture ratio and low leakage current, and has extremely high application value.

[0043] In some embodiments of the present application, the structure of the benzobisthiazole organic dye is as follows:

[0044]

[0045]

[0046] The second aspect of the present application proposes a preparation method of a benzobisthiazole organic dye, comprising the following steps (general step S1):

[0047] In a protective atmosphere, the reactant A, the reactant B, the reactant C and the palladium catalyst are mixed and heated to generate a C-C coupling reaction, thereby generating the benzobisthiazole organic dye (P1);

[0048] The structure of the reactant A is The structure of the reactant B is The reactant A and the reactant B can be the same or different; R1 is independently selected from substituted or unsubstituted alkyl, substituted or unsubstituted oxaalkyl, substituted or unsubstituted alkylphenyl each time; R2 is independently selected from H atom, halogen, substituted or unsubstituted alkyl, substituted or unsubstituted alicyclic group, phenyl, substituted or unsubstituted alkylphenyl, substituted or unsubstituted oxaalkyl, substituted or unsubstituted alkylthiophenyl, substituted or unsubstituted alkylsilane group, substituted or unsubstituted alkylalkyne group each time.

[0049] The structure of the reactant C is

[0050] The chemical formula of the above reaction is

[0051]

[0052] In some embodiments of the present application, the palladium catalyst is selected from one or more of dichlorobistriphenylphosphine palladium (PdCl2(PPh3)2), dichloro[1,1'-bis(diphenylphosphino)ferrocene]palladium (PdCl2(dppf)), palladium acetate (Pd(OAc)2), and tetrakis(triphenylphosphine)palladium (Pd(PPh3)4).

[0053] In some embodiments of the present application, the molar ratio of the reactants is: reactant A: reactant B: reactant C: palladium catalyst = 1:1:(0.8-1.3):(0.01-0.15).

[0054] In a specific embodiment of the present application, the specific steps of the above reaction are as follows:

[0055] (1) Under the protection of nitrogen, reactants A, B (which can be the same or different) and C (i.e. 4,7-dibromobenzo[1,2-c:4,5-c']bis([1,2,5]thiadiazole)) and a palladium catalyst are added to a pre-dried 100 ml round-bottom flask in a molar ratio of reactant A: reactant B: reactant C: palladium catalyst = 1:1:(0.8-1.3):(0.01-0.15), followed by the addition of 20-50 ml of super-dry solvent (with a water content of less than 50 ppm, such as 1,4-dioxane, toluene, tetrahydrofuran, etc.), to obtain a mixed solution;

[0056] (2) The mixed solution is heated to reflux temperature and reacted for 10-48 h to obtain a mixture;

[0057] (3) After the mixture is cooled to room temperature, the solvent is removed, then n-hexane: dichloromethane = 1:1-10:1 is used as an eluent, and the mixture is purified by silica gel column chromatography, followed by recrystallization, suction filtration and drying, and further purification by temperature gradient sublimation in a vacuum to obtain the above-mentioned benzo-bis-thiadiazole organic dye P1.

[0058] The present application also provides a preparation method of a benzo-bis-thiadiazole organic dye, which comprises the following steps (general step S2):

[0059] In a protective atmosphere, reactants D, E, F and a palladium catalyst are mixed and heated to undergo a C-C coupling reaction to generate the benzo-bis-thiadiazole organic dye (P1);

[0060] wherein the structure of the reactant D is (Bu)3Sn-R1, and R1 is selected from substituted or unsubstituted alkyl, substituted or unsubstituted oxaalkyl, and substituted or unsubstituted alkylphenyl.

[0061] The structural formula of the reactant E is (Bu)3Sn-R2, and R2 is selected from H atom, halogen, substituted or unsubstituted alkyl, substituted or unsubstituted alicyclic group, phenyl, substituted or unsubstituted alkylphenyl, substituted or unsubstituted oxaalkyl, substituted or unsubstituted alkylthiophenyl, substituted or unsubstituted alkylsilyl, and substituted or unsubstituted alkylalkynyl;

[0062] The structural formula of the reactant F is X is selected from H, I, Br, and Cl.

[0063] The chemical formula of the above reaction is

[0064]

[0065] In some embodiments of the present application, the palladium catalyst is selected from one or more of dichlorobistriphenylphosphine palladium (PdCl2(PPh3)2), dichloro[1,1'-bis(diphenylphosphino)ferrocene]palladium (PdCl2(dppf)), palladium acetate (Pd(OAc)2), and tetrakis(triphenylphosphine)palladium (Pd(PPh3)4).

[0066] In some embodiments of the present application, the molar ratio of each reactant is: reactant F: reactant D: reactant E: palladium catalyst = 1: (1.2-4.8): (1.2-4.8): (0.05-0.15).

[0067] In a specific embodiment of the present application, the specific steps of the above reaction are as follows:

[0068] (1) Under the protection of nitrogen, the reactant D, the reactant E, the reactant F, and the palladium catalyst are added into a pre-dried 100 ml round-bottom flask in a molar ratio of reactant F: reactant D: reactant E: palladium catalyst = 1: (1.2-4.8): (1.2-4.8): (0.05-0.15), and then 20-50 ml of super-dry solvent (with water content less than 50 ppm, such as 1,4-dioxane, toluene, tetrahydrofuran, etc.) is added to obtain a mixed solution;

[0069] (2) The mixed solution is warmed to reflux temperature, and reacted for 10-48 h to obtain a mixture;

[0070] (3) After the mixture is cooled to room temperature, a potassium fluoride solution is added for stirring to remove excess tin compounds, diatomite filtration is performed, the solvent is removed by reduced pressure distillation, then n-hexane:dichloromethane = 1:1-10:1 is used as an eluent for purification by silica gel column chromatography, and finally, after recrystallization, suction filtration, and drying, further purification is performed by temperature gradient sublimation in a vacuum to obtain the benzobisthiazolyl organic dye P1.

[0071] The method for preparing the benzo-bisthiazole organic dye has at least the following beneficial effects: the method for preparing the benzo-bisthiazole derivative provided by the application adopts the palladium catalyzed coupling reaction (such as Suzuki-Miyaura coupling reaction, Stille coupling reaction, and Sonogashira coupling reaction), which has the advantages of mild reaction condition, good functional group tolerance, and non-sensitivity of the substrate to water and air, and has a high yield and the possibility of large-scale production. In addition, the raw materials in the synthesis process are easy to obtain, the synthesis process is simple and easy to operate, and the obtained derivative is relatively stable, can be separated and purified by column chromatography, and will not decompose or react with the chromatographic column to be difficult to elute during the separation process.

[0072] In a third aspect, the application provides a use of the above-mentioned benzo-bisthiazole organic dye in an electrowetting display technology.

[0073] The application has at least the following beneficial effects: the application provides a use of a novel benzo-bisthiazole compound in an electrowetting display technology. The above-mentioned compound has a pure color, a high color saturation, and a very high solubility, and a high molar absorption coefficient (more than 1.5*10 4 L·mol -1 ·cm -1 ); as an ink for synthesizing an organic dye, the molar absorption coefficient ε can reach 1.2*10 4 , the color is bright, the saturation is high, and the compound is very suitable for the electrowetting display. The electrowetting device prepared by using the above-mentioned ink has good electrowetting performance, a low switching voltage, a fast response time, and no backflow phenomenon under a constant voltage.

[0074] The obtained benzo-bisthiazole organic dye is used as an ink material in the electrowetting display technology (for example, an electrowetting display), and there is no special requirement for the electrowetting device. The electrowetting device can be prepared by using a conventional preparation method in the art, and other raw materials involved are conventional materials in the art, and a person skilled in the art can reasonably select them according to the needs, which will not be described here.

[0075] In a fourth aspect, the application provides an electrowetting display ink, which comprises the above-mentioned benzo-bisthiazole organic dye or the benzo-bisthiazole organic dye prepared by the above-mentioned method.

[0076] The electro-wetting display ink according to the embodiment of the present application has at least the following beneficial effects: the present application develops a series of organic dyes applicable to the electro-wetting device ink based on the benzodithiazole (BBT) skeleton, the structure of the organic dyes has pure color and high color saturation, the molar absorption coefficient is high (more than 1.5*10 4 L·mol -1 ·cm -1 ), and the solubility in the non-polar organic solvent is relatively high. The ink synthesized based on the above-mentioned organic dyes has extremely high solubility and molar extinction coefficient, and the molar absorption coefficient ε of the ink can reach 1.2*10 4 L·mol -1 ·cm -1 , and the color is bright and the saturation is high. The electro-wetting device made of the ink has the characteristics of easy driving, large aperture ratio and low leakage current, and has no backflow phenomenon under constant voltage, and has high practical application value.

[0077] In some embodiments of the present application, the electro-wetting display ink comprises 1-30 parts by mass of the benzodithiazole organic dye and 5-100 parts of the non-polar solvent.

[0078] In some preferred embodiments of the present application, the non-polar solvent comprises at least one of n-decane, n-dodecane, n-tetradecane, n-hexadecane, fluorine-containing alkane and silane.

[0079] In a fifth aspect of the present application, a display is provided, which comprises the electro-wetting display ink described above.

[0080] The display according to the embodiment of the present application has at least the following beneficial effects: the ink prepared by the novel benzodithiazole compound synthesized by the present application has a molar absorption coefficient ε of 1.2*10 4 , and the color is bright and the saturation is high, which is very suitable for electro-wetting display. The electro-wetting display made of the above-mentioned ink has good electro-wetting performance, low switching voltage, fast response time, and no backflow phenomenon under constant voltage. BRIEF DESCRIPTION OF DRAWINGS

[0081] The present application will be further described below in conjunction with the drawings and examples, in which:

[0082] Figure 1 The nuclear magnetic resonance hydrogen spectrum of compound 2 synthesized in the embodiment 1 of the present application is shown in the following figure:

[0083] Figure 2 The nuclear magnetic resonance hydrogen spectrum of compound 3 synthesized in the embodiment 2 of the present application is shown in the following figure:

[0084] Figure 3The 1H NMR spectrum of compound 4 synthesized in Example 3 of this invention;

[0085] Figure 4 The 1H NMR spectrum of compound 5 synthesized in Example 4 of this invention;

[0086] Figure 5 The 1H NMR spectrum of compound 6 synthesized in Example 5 of this invention;

[0087] Figure 6 The UV-Vis absorption spectrum of organic dye compound 2 synthesized in Example 1 is shown below.

[0088] Figure 7 The UV-Vis absorption spectrum of organic dye compound 4 synthesized in Example 3 is shown below.

[0089] Figure 8 The UV-Vis absorption spectrum of organic dye compound 5 synthesized in Example 4 is shown below.

[0090] Figure 9 The UV-Vis absorption spectrum of organic dye compound 6 synthesized in Example 5 is shown below.

[0091] Figure 10 A full view of the electrowetting device made from organic dye compound 6 synthesized in Example 5;

[0092] Figure 11 The diagram shows the state of the electrowetting device made from organic dye compound 6 synthesized in Example 5 under 16V driving opening. Detailed Implementation

[0093] The following will describe the concept and technical effects of the present invention clearly and completely with reference to embodiments, so as to fully understand the purpose, features and effects of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are all within the scope of protection of the present invention.

[0094] In the description of this invention, the terms "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0095] In the description of the present application, unless otherwise specified, the numerical range "a~b" represents a shorthand notation for any real combination of a to b, where a and b are real numbers. Unless otherwise specified, each reaction or operation step can be carried out in sequence or not in sequence. Preferably, the reaction method in the present application is carried out in sequence.

[0096] In the following examples, unless otherwise specified, the techniques or conditions described in the literature in the art or according to the product manual are used. All reagents or instruments, unless otherwise specified, are conventional products that can be commercially available. All reaction conditions, unless otherwise specified, are carried out under suitable conditions. The percentages, unless otherwise specified, are mass percentages.

[0097] Example 1

[0098] 4,8-Bis[4-(2-octyldodecyl)-2-thienyl]-2λ 4 δ 2 Synthesis of 4,8-bis[4-(2-octyldodecyl)-2-thienyl]-2λ

[0099]

[0100] Reaction a: In a 100 ml two-necked round bottom flask, 4,7-dibromo-benzo[1,2-c:4,5-c']bis([1,2,5]thiadiazole) (200 mg, 0.57 mmol), tributyl(4-(2-octyldodecyl)thiophen-2-yl)tin (800 mg, 1.22 mmol), tetrakis(triphenylphosphine)palladium (66 mg, 10 mol%) were added to 40 ml of water-free toluene, the resulting mixture was bubbled with argon for 10 min, and then the reaction was carried out at 110°C for 20 hours. After the reaction was completed, the solvent was removed by distillation under reduced pressure after cooling to room temperature, and the crude product was purified by column chromatography with dichloromethane:n-hexane = 1:1 as an eluent, and the product, compound 2 (330 mg, yield 63%), was obtained after drying.

[0101] NMR data of compound 2: 1 H NMR (600 MHz, CDCl3): δ (PPM) = 8.73 (s, 2H), 7.24 (s, 2H), 2.70 (d, J = 6.9 Hz, 4H), 1.76 (p, J = 6.1 Hz, 2H), 1.38 - 1.22 (m, 64H), 0.86 (t, J = 6.9 Hz, 12H).

[0102] The hydrogen spectrum of compound 2 is shown in Figure 1 .

[0103] Example 2

[0104] Synthesis of 4,8-Bis[5-bromo-4-(2-octyldodecyl)-2-thienyl]-2λ4δ2-benzo[1,2-c:4,5-c′]bis[1,2,5]thiadiazole (compound 3)

[0105]

[0106] Reaction b:

[0107] Compound 2 obtained in Example 1, namely 4,8-bis[4-(2-octyldodecyl)-2-thienyl]-2λ 4 δ 2 4,7-bis[5-bromo-4-(2-octyldodecyl)-thiophene-2-yl]-benzobisthiodiazole (0.8 g, 0.87 mmol) and NBS (313 mg, 17.6 mmol) were dissolved in THF (40 mL), and the reaction system was stirred at room temperature and pressure for 12 hours. After removing the solvent, the solid was dissolved in a small amount of DCM, and the solution was then added dropwise to a large amount of methanol. The precipitate of 4,7-bis[5-bromo-4-(2-octyldodecyl)-thiophene-2-yl]-benzobisthiodiazole was then collected, eluent by column chromatography with petroleum ether, and the collected and concentrated product compound 3 (0.89 g, 95% yield) was dried under vacuum.

[0108] The 1H NMR characterization data of compound 3: 1 H NMR (600MHz, CDCl3): δ (PPM) = 8.64 (s, 2H), 2.64 (d, J = 7.8Hz, 4H), 1.82 (m, 2H), 1.29 (m, 64H), 0.87 (m, 12H).

[0109] The proton NMR spectrum of compound 3 is as follows: Figure 2 As shown.

[0110] Example 3

[0111]

[0112] Reaction c:

[0113] A mixture of 4,7-dibromobenzo[l,2-c:4,5-c']bis[l,2,5]thiadiazole (32 mg, 0.09 mmol), tributyl(4-(2-octyldodecyl)thiophen-2-yl)tin and tributyl(5-(2- ethylhexyl)-4-(2-octyldodecyl)thiophen-2-yl)tin (140 mg, ca. 0.198 mmol), tetrakis(triphenylphosphine)palladium (10.4 mg, 10 mol%) were added to 20 ml of freshly distilled toluene and the resulting mixture was bubbled with argon for 10 min before the reaction was refluxed at 110 °C for 20 h. After the reaction was completed, the solvent was removed by distillation under reduced pressure after cooling to room temperature, and the crude product was purified by column chromatography using dichloromethane: n-hexane = 1:1 as eluent to give compound 4 (13.6 mg, 0.0132 mmol) as a blue solid after drying, with a yield of 14.6%.

[0114] NMR characterization data of compound 4: 1 H NMR (600 MHz, CDC13): δ (PPM) = 8.81 (d, J = 1.4 Hz, 1H), 8.77 (s, 1H), 7.25 (d, J = 1.3 Hz, 1H), 2.80 (dd, J = 7.1, 3.0 Hz, 2H), 2.71 (d, J = 6.8 Hz, 2H), 2.58 (d, J = 7.2 Hz, 3H), 1.77 (d, J = 15.6 Hz, 3H), 1.39 - 1.17 (m, 72H), 0.95 - 0.79 (m, 18H).

[0115] The hydrogen spectrum of compound 4 is shown in Figure 3

[0116] Example 4

[0117]

[0118] ​Reaction d: 100 mg (0.09 mmol) of compound 3, i.e. 4,8-di(5-bromo-4-(2- octyldodecyl)thienyl)-benzo[l,2-c;4,5-c']bis[l,2,5]thiadiazole, obtained from example 2, 58.53 mg (0.225 mmol) of 4-tert-butylphenylboronic acid pinacol ester, 10 ml of 2M potassium carbonate solution, 10 mg (0.009 mmol) of tetrakis(triphenylphosphine)palladium [Pd(PPh3)4], were placed in a 100 ml two-necked flask, 20 ml of toluene and 10 ml of ethanol were added, and the mixture was heated to 90°C for 20 hours. After the reaction was completed, the temperature was slowly cooled to room temperature, and then the mixture was poured into water and extracted twice with dichloromethane (DCM), and then the organic layer was collected and dried over magnesium sulfate, the reagent was removed by rotary evaporation under reduced pressure, and then the product was separated and purified by column chromatography using n-hexane: dichloromethane = 1:1 as the eluent, and 88 mg of yellow-green solid, i.e. compound 5, was obtained in a yield of 81.1%.

[0119] NMR data of compound 5: 1 H NMR (600 MHz, CDC13): δ (PPM) = 7.46 (s, 2H), 7.57-7.52 (m, 4H), 7.50-7.44 (m, 4H), 2.88 (dd, J = 14.1, 0.8 Hz, 2H), 2.60 (dd, J = 14.1, 0.8 Hz, 2H), 1.77 (p, J = 7.3 Hz, 2H), 1.44-1.06 (m, 80H), 0.87-0.90 (m, 12H).

[0120] The hydrogen spectrum of compound 5 is shown in Figure 4 .

[0121] Example 5

[0122]

[0123] Reaction e: In a two-necked 100 mL round-bottom flask, 200 mg (0.18 mmol) of compound 3, i.e. 4,8-di(5-bromo-4-(2-octyldodecyl)thiophenyl)-benzo[l,2-c;4,5-c']bisl[ 1,2,5]thiadiazole, obtained from Example 2, 13 mg (10 mol%) of dichlorobis(triphenylphosphine) palladium (PdCl2(PPh3)2), 304 mg (0.465 mmol) of tributyl(4-(2-octyldodecyl)thiophen-2-yl)tin were added to 10 mL of freshly distilled 1,4-dioxane, the resulting mixture was bubbled with argon for 10 min, then refluxed for 20 hours. After the reaction was completed, the solvent was removed under reduced pressure, the crude product was purified by column chromatography, using petroleum ether as eluent to remove the unreacted tin compound, and 241.4 mg of yellow-green solid, i.e. compound 6, was isolated with a yield of 85.2%.

[0124] NMR characterization data of compound 6: 1 H NMR (600 MHz, CDC13): δ (PPM) = 8.78 (s, 2H), 7.15 (d, J = 1.4 Hz, 2H), 6.94 (s, 2H), 2.85 (d, J = 7.3 Hz, 4H), 2.59 (d, J = 6.9 Hz, 4H), 1.86 (h, J = 6.4 Hz, 2H), 1.69 (p, J = 6.0 Hz, 2H), 1.40 - 1.15 (m, 128H), 0.87 (dq, J = 13.3, 6.7 Hz, 24H).

[0125] The hydrogen spectrum of compound 6 is shown in Figure 5 .

[0126] Example 6

[0127] This example tests the relevant properties of the compounds obtained in Examples 1, 3, 4, and 5.

[0128] The specific test method is as follows: 0.1 g of the compound obtained in each specific example was taken, and an organic dye aqueous solution of 10 ml was prepared using n-eicosane as the solvent; then the color was observed by visual observation, and the spectral wavelength λ max and the molar absorption coefficient ε at the maximum absorbance were tested by ultraviolet-visible spectrophotometry; and the solubility of the obtained organic dye in n-eicosane at 20°C was tested by the equilibrium method, i.e. by testing the concentration of the substance in the supernatant of the supersaturated solution. The test results are shown in Table 1. The organic dye obtained from the compounds in Examples 1, 3, 4, and 5 and the ultraviolet-visible absorption spectrum thereof are shown in Figures 6-9 .

[0129] Table 1

[0130]

[0131] From Table 1 and Figures 6-9 It can be seen that the maximum absorption peaks of the organic dyes of the present application are all above 700 nm, and the color is pure cyan color; the prepared electrowetting ink material has very high solubility and molar extinction coefficient, and the ink molar extinction coefficient can reach 1.2 x 10 4 L·mol -1 ·cm -1 The above has bright color and high saturation.

[0132] Example 7

[0133] An electrowetting device was prepared using the organic dye (compound 6) of Example 5, as shown in Figure 10 The prepared electrowetting device was tested for open state performance under 16V voltage driving, as shown in Figure 11 Three batches of electrowetting devices 1, 2 and 3 were prepared using the organic dye (compound 6) of Example 5, and their performances were tested, as shown in Table 2.

[0134] Table 2

[0135]

[0136]

[0137] It has been tested that the electrowetting display device filled with the ink prepared by the present application has low switching voltage, fast response time, high open rate, and no backflow phenomenon under constant voltage, further proving that the ink prepared from the organic dye described in the present application is very suitable for electrowetting display.

[0138] The above examples only express several embodiments of the present application, and the description is more specific and detailed, but it should not be understood as limiting the scope of the present patent. It should be noted that for ordinary skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are all within the scope of protection of the present application.

Claims

1. An electrowetting display ink, characterized in that, The electrowetting display ink includes benzobisthiadiazole organic dyes, the general structural formula of which is shown in formula (I): Each time R1 appears, it is independently selected from substituted or unsubstituted alkyl, substituted or unsubstituted oxalyl, or substituted or unsubstituted alkylphenyl. Each time R2 appears, it is independently selected from H atom, halogen, substituted or unsubstituted alkyl, substituted or unsubstituted alicyclic, phenyl, substituted or unsubstituted alkylphenyl, substituted or unsubstituted oxalyl, substituted or unsubstituted alkylthiophene, substituted or unsubstituted alkylsilyl, substituted or unsubstituted alkylynyl. Wherein, "substituted or unsubstituted" means that the group may or may not be further substituted by one or more groups selected from the following: alkyl, alkenyl, alkynyl, aryl, halogen, haloalkyl, haloalkenyl, haloalkynyl, haloaryl, hydroxyl, alkoxy, alkenyloxy, aryloxy, benzyloxy, haloalkoxy, haloalkenyloxy, haloaryloxy, nitro, nitroalkyl, nitroalkenyl, nitroalkynyl, nitroheterocyclic, amino, alkylamino, dialkylamino, alkenylamino, alkynylamino, arylamino, diarylamino, phenylamino, diphenylamino, benzylamino, dibenzylamino, hydrazyl, acyl, acylamino, diacylamino, acyloxy, heterocyclic, heterocyclic, heterocyclic amino, haloheterocyclic, carboxyl ester, carboxyl.

2. The electrowetting display ink according to claim 1, characterized in that, R1 is selected from substituted or unsubstituted C4-C20 alkyl, substituted or unsubstituted C4-C20 oxalyl, and substituted or unsubstituted C7-C20 alkylphenyl.

3. The electrowetting display ink according to claim 2, characterized in that, R1 is selected from substituted or unsubstituted C13-C20 alkyl, substituted or unsubstituted C8-C15 oxalyl, and substituted or unsubstituted C7-C13 alkylphenyl.

4. The electrowetting display ink according to claim 1, characterized in that, The R2 is selected from substituted or unsubstituted C4-C20 alkyl, substituted or unsubstituted C4-C20 alicyclic, substituted or unsubstituted C7-C20 alkylphenyl, substituted or unsubstituted C4-C20 oxalyl, substituted or unsubstituted C4-C20 alkylthiophene, substituted or unsubstituted C4-C20 alkylsilyl, and substituted or unsubstituted C4-C20 alkylynyl.

5. The electrowetting display ink according to claim 4, characterized in that, The R2 is selected from substituted or unsubstituted C13-C20 alkyl, substituted or unsubstituted C4-C10 alicyclic, substituted or unsubstituted C7-C10 alkylphenyl, substituted or unsubstituted C5-C15 oxaalkyl, 3-(2-octyldodecyl)thiophene, triisopropylsilyl, and 5-ethynylundecane.

6. The electrowetting display ink according to claim 1, characterized in that, R1 is selected from butyl, cyclobutyl, pentyl, cyclopentylene, n-hexyl, n-heptyl, n-octyl, isooctyl, 2-ethylhexyl, nonyl, n-decyl, n-undecyl, n-dodecyl, n-tridecyl, n-tetradecyl, n-pentadecanyl, n-hexadecyl, n-heptadecyl, n-octadecyl, n-nonadecanyl, n-eicosyl, 2-nonyldecyl, 2-pentylhexyl, 2-heptyloctyl, and 2-octyldodecyl. And / or, R2 is selected from butyl, cyclobutyl, pentyl, cyclopentylene, n-hexyl, n-heptyl, n-octyl, isooctyl, 2-ethylhexyl, nonyl, n-decyl, n-undecyl, n-dodecyl, n-tridecyl, n-tetradecyl, n-pentadecanyl, n-hexadecyl, n-heptadecyl, n-octadecyl, n-nonadecanyl, n-eicosyl, 2-nonyldecyl, 2-pentylhexyl, 2-heptyloctyl, 2-octyldodecyl, 3-(2-ethylhexoxy)propyl, phenyl, methylphenyl, ethylphenyl, propylphenyl, butylphenyl, pentylphenyl, hexylphenyl, heptaphenyl, octylphenyl, nonylphenyl, decylphenyl, undecylphenyl, dodecylphenyl, tridecylphenyl, tetradecylphenyl.

7. The electrowetting display ink according to claim 1, characterized in that, The structural formula of the benzobisthiadiazole organic dye is shown below:

8. The electrowetting display ink according to claim 1, characterized in that, The preparation method of the benzobisthiadiazole organic dye includes the following steps: Under a protective atmosphere, reactants A, B, C and palladium catalyst are mixed and heated to undergo a C-C coupling reaction, generating the benzobisthiadiazole organic dye. The structural formula of reactant A is as follows: The structural formula of reactant B is as follows: The reactant A and reactant B may be the same or different; each time R1 appears, it is independently selected from substituted or unsubstituted alkyl, substituted or unsubstituted oxalyl, substituted or unsubstituted alkylphenyl; each time R2 appears, it is independently selected from H atom, halogen, substituted or unsubstituted alkyl, substituted or unsubstituted alicyclic, phenyl, substituted or unsubstituted alkylphenyl, substituted or unsubstituted oxalyl, substituted or unsubstituted alkylthiophene, substituted or unsubstituted alkylsilyl, substituted or unsubstituted alkylynyl. The structural formula of reactant C is:

9. The electrowetting display ink according to claim 1, characterized in that, The preparation method of the benzobisthiadiazole organic dye includes the following steps: Under a protective atmosphere, reactants D, E, F and palladium catalyst are mixed and heated to undergo a C-C coupling reaction, generating the benzobisthiadiazole organic dye. The reactant D has the structural formula (Bu)3Sn-R1, where R1 is selected from substituted or unsubstituted alkyl, substituted or unsubstituted oxalyl, or substituted or unsubstituted alkylphenyl. The reactant E has the structural formula (Bu)3Sn-R2, where R2 is selected from H atoms, halogens, substituted or unsubstituted alkyl groups, substituted or unsubstituted alicyclic groups, phenyl groups, substituted or unsubstituted alkylphenyl groups, substituted or unsubstituted oxalyl groups, substituted or unsubstituted alkylthiophene groups, substituted or unsubstituted alkylsilyl groups, and substituted or unsubstituted alkylynyl groups. The structural formula of reactant F is: X is selected from H, I, Br, and Cl.

10. The electrowetting display ink according to claim 1, characterized in that, The electrowetting display ink comprises 1 to 30 parts by mass of the benzobisthiadiazole organic dye and 5 to 100 parts by mass of a nonpolar solvent.

11. The application of an electrowetting display ink as described in any one of claims 1-10 in electrowetting display technology.

12. A display, characterized in that, The display includes the electrowetting display ink as described in any one of claims 1-10.

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