A bisnaphthalimide blue dye, a preparation method thereof and an electrowetting display ink

Abstract

This invention relates to a bis(naphthalimide)-based blue dye, its preparation method, and an electrowetting display ink. The dye has the following structural formula: it comprises two naphthalimide units, each containing one aromatic amine group and two straight-chain or branched alkyl groups, bridged by a diamine. The preparation method uses dibromonaphthalimide as an intermediate, which undergoes nucleophilic substitution reactions with the diamine and aromatic amine, respectively, to obtain the dye. The preparation method of the bis(naphthalimide)-based blue dye provided by this invention is simple in procedure, has mild reaction conditions, and is suitable for large-scale preparation.

Description

Technical Field

[0001] This invention relates to the field of electrowetting ink technology, specifically to a bis(naphthyl)diimide blue dye, its preparation method, and an electrowetting display ink. Background Technology

[0002] Electrowetting displays (EVDs) are a reflective display solution based on the dielectric wetting effect. This technology is considered one of the most promising display technologies due to its excellent readability in strong light environments, low power consumption, video-level response speed, and potential for full-color and flexible displays. Its working principle involves controlling the surface wettability of a hydrophobic layer with voltage, thereby changing the contact angle of the ink on the hydrophobic layer and achieving image display. Specifically: without voltage, the ink spreads evenly on the hydrophobic layer, forming a colored pixel; when voltage is applied, the interfacial tension between the ink, polar liquid, and hydrophobic layer changes, compressing the ink and forming a transparent or substrate-colored pixel.

[0003] In electrowetting display technology, RGBK (red, green, blue, and black) and CMY (cyan, magenta, and yellow) are two core solutions for achieving full-color display. Compared to the vertically stacked CMY solution, RGBK-based display devices have a simpler structure, more mature manufacturing process, and greater advantages in flexible displays. As a core material, electrowetting dyes are crucial for achieving high-performance displays, especially those with high molar absorptivity (ε): to achieve the same contrast ratio, if the dye's molar absorptivity is low, the dye concentration in the ink needs to be increased. This not only places higher demands on the dye's solubility but also increases the ink's viscosity, thus reducing the device's response speed. Blue electrowetting display dyes are one of the primary color dyes in the RGBK full-color display solution; however, currently reported blue dyes still have certain shortcomings. For example, patent CN 120504975 A yielded anthraquinone blue dye, but its molar absorptivity is relatively low (16971 L·mol⁻¹). -1 ·cm -1 Patent CN 115260197 B yielded an organic perylene blue dye, but it had the problem of impure color (blue-purple).

[0004] Therefore, developing high-performance blue electrowetting display dyes and corresponding inks is of great significance for promoting the development of this field. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of current technologies by providing a bis(naphthalenediimide)-based blue dye, its preparation method, and an electrowetting display ink. This dye comprises two naphthalenediimide units, each containing one aromatic amine group and two straight-chain or branched alkyl groups, bridged by a diamine. The preparation method uses dibromonaphthalenediimide as an intermediate, represented by formula (IV-a) or (IV-b), as an intermediate, and obtains the dye through nucleophilic substitution reactions with the diamine and aromatic amine, respectively. The preparation method of the bis(naphthalenediimide)-based blue dye provided by this invention has simple steps, mild reaction conditions, and is suitable for large-scale preparation.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A bis(naphthyl)imide blue dye, the general chemical structure of which is shown in formula (I): Formula (I) In equation (I), G1 can be any of the following structural formulas: ; G2 and G3 are each independently selected from any of the following structural formulas: ; Among them, R1, R2, R5, R6, R7, R 11 R 12 Each is independently selected from straight-chain or branched alkyl groups of C1 to C30, R3, R4, R8, R9, R 10 Each is independently selected from H, C1 to C30 straight-chain or branched alkyl groups, and R9 and R 10 Not both H; The linking sites of the aforementioned groups are represented.

[0007] Preferably, R1, R2, R5, R6, R7, R 11 R 12 It is a straight-chain or branched alkyl group from C1 to C24, with R3, R4, R8, R9, and R6 as the base groups. 10 It is a straight-chain or branched alkyl group of H, C1-C24, R9 and R 10 They are not both H.

[0008] More preferably, the structural formula of the bis(naphthyl)imide blue dye is shown in formulas (BNDI-1) to (BNDI-7): Formula (BNDI-1) Formula (BNDI-2) Formula (BNDI-3) Formula (BNDI-4) Formula (BNDI-5) Formula (BNDI-6) Formula (BNDI-7) The method for preparing the bis(naphthyl)imide blue dye includes any one of the following three methods: Method 1 includes the following steps: S1: Under the protection of an inert gas and in the presence of a first base, substance A, substance B, and substance C are added to a first solvent and undergo a nucleophilic substitution reaction at 45–180°C for 2–36 h to obtain the compound shown in formula (II); substance B and substance C may be the same or different. Formula (II); Among them, substance A is the compound shown in formula (III), substance B is the compound shown in formula (IV-a), and substance C is the compound shown in formula (IV-b); H2N—G1—NH2 Formula (III); In equation (III), G1 is defined in the same way as G1 in equation (I) above; Formula (IV-a); Formula (IV-b); In equation (IV-a), R1 is defined the same as R1 in equation (I) above; in equation (IV-b), R2 is defined the same as R2 in equation (I) above. The molar ratio of substance A, substance B, substance C, and the first base is 1:(1-5):(1-5):(1-10); The preparation method of the compounds shown in formulas (IV-a) and (IV-b) above specifically includes the following steps: 2,6-Dibromonaphthalene-1,4,5,8-tetracarboxylic dianhydride (CAS No.: 83204-68-6) reacts with Y1—NH2 in the presence of glacial acetic acid to give the compound shown in formula (IV-a) or (IV-b). In Y1—NH2, the definition of Y1 is the same as the definitions of R1 and R2 in the aforementioned formula (I); S2: Under inert gas protection, the compound shown in formula (II) and substance D are added to the second solvent and undergo a nucleophilic substitution reaction at 80-180°C for 8-60 h to obtain the bis(naphthalene)imide dye shown in formula (I); Wherein, substance D is the compound shown in formula (V); Y2—NH—X formula (V); In equation (V), the definition of Y2 is the same as the definition of G2 and G3 in the aforementioned equation (I), and the definition of X is the same as the definition of R3 and R4 in the aforementioned equation (I); The molar ratio of the compound shown in formula (II) to substance D is 1:(2-25).

[0009] Alternatively, method two includes the following steps: S1: Under the protection of an inert gas and in the presence of a second base, substance B (or substance C) and substance D are added to a third solvent and undergo a nucleophilic substitution reaction at 45–180 °C for 2–36 h to obtain the compound shown in formula (VI-a) or (VI-b). Formula (VI-a); Formula (VI-b); In equation (VI-a), R1, R3, and G2 are defined the same as R1, R3, and G2 in equation (I) above; in equation (VI-b), R2, R4, and G3 are defined the same as R2, R4, and G3 in equation (I) above. The molar ratio of substance B (or substance C), substance D, and the second base is 1:(0.5-1.5):(0.5-5); S2: Under the protection of an inert gas and in the presence of a third base, substance A, along with the compound shown in formula (VI-a) and the compound shown in formula (VI-b) (which may be the same as or different from the compound shown in formula (VI-a)), are added to a fourth solvent and undergo a nucleophilic substitution reaction at 80–180 °C for 8–60 h to obtain the bis(naphthalene)imide dye shown in formula (I). The molar ratio of substance A, the compound shown in formula (VI-a), the compound shown in formula (VI-b), and the third base is 1:(1-5):(1-5):(1-10).

[0010] Alternatively, method three includes the following steps: S1: Under the protection of an inert gas, the compound shown in formula (VI-a) and substance A are added to the fifth solvent and undergo a nucleophilic substitution reaction at 80-180°C for 8-60 h to obtain the compound shown in formula (VII). Equation (VII); In equation (VII), R1, R3, G1, and G2 are defined in the same way as R1, R3, G1, and G2 in equation (I) above. The molar ratio of the compound and substance A shown in formula (VI-a) is 1:(1~25); S2: Under the protection of an inert gas and in the presence of a fourth base, the compound shown in formula (VII) and substance C are added to the sixth solvent and undergo a nucleophilic substitution reaction at 45–180 °C for 2–36 h to obtain the compound shown in formula (VIII). Formula (VIII); In equation (VIII), R1, R2, R3, G1, and G2 are defined in the same way as R1, R2, R3, G1, and G2 in equation (I) above. The molar ratio of the compound shown in formula (VII), substance C, and the fourth base is 1:(1-5):(0.5-5); S3: Under inert gas protection, the compound shown in formula (VIII) and substance D are added to the seventh solvent and undergo a nucleophilic substitution reaction at 80-180°C for 8-60 h to obtain the bis(naphthalene)imide dye shown in formula (I); The molar ratio of the compound shown in formula (VIII) to substance D is 1:(1-25).

[0011] The first, second, third, and fourth bases may be the same or different, and are at least one of sodium carbonate, potassium carbonate, cesium carbonate, and sodium tert-butoxide.

[0012] The first, second, third, fourth, fifth, sixth, and seventh solvents may be the same or different, and are tetrahydrofuran, 1,4-dihydrofuran, etc. Dioxane, chloroform, toluene N , N Dimethylformamide (DMF) N At least one of methylpyrrolidone (NMP) and dimethyl sulfoxide.

[0013] The inert gas is argon or nitrogen.

[0014] An ink comprising the aforementioned bis(naphthyl)imide blue dye; Preferably, the ink comprises 0.0010 to 30 parts by weight of the bis(naphthalimide) blue dye and 70 to 100 parts by weight of a nonpolar solvent; The nonpolar solvent is at least one of n-decane, n-dodecane, n-tridecane, n-tetradecane, n-hexadecane, squalane, fluorinated alkanes, and silanes.

[0015] The beneficial effects of this invention are as follows: The bis(naphthalimide) blue dye provided by this invention achieves a high molar absorptivity (up to 34650 L·mol⁻¹) by bridging two naphthalimide units containing aromatic amine groups with a diamine. -1 ·cm-1 (This is twice the corresponding value of patent CN120504975 A); at the same time, the long-chain alkyl groups on its imide and the alkyl groups introduced on the aromatic amine side chains help increase its solubility in non-polar solvents, and the quality factor FoM value can reach 3×10. 3 (For comparison, the dye FoM < 800 reported in Materials Science and Engineering B, 2012, 177, 1672-1677). The method for preparing bis(naphthalimide) blue dyes provided by this invention has simple steps and mild reaction conditions, making it suitable for large-scale preparation. Furthermore, by simply changing the structure of the diamine, aromatic amine, and contained alkyl groups, the solubility of the dye in non-polar solvents can be effectively controlled, resulting in a high FoM value. In addition, the ink prepared by dissolving the bis(naphthalimide) dye in a non-polar solvent exhibits a purer blue color than that of mono(naphthalimide) dyes, showing excellent application prospects in the field of electrowetting displays. Attached Figure Description

[0016] Figure 1 The dye prepared in Example 1 1 H NMR spectrum; Figure 2 The dye prepared in Example 2 1 H NMR spectrum; Figure 3 The dye prepared in Example 3 1 H NMR spectrum; Figure 4 The dye prepared in Example 4 1 H NMR spectrum; Figure 5 The dye prepared in Example 6 1 H NMR spectrum; Figure 6 The dye prepared in Example 7 1 H NMR spectrum; Figure 7 The dye prepared in Example 8 1 H NMR spectrum; Figure 8 The UV-Vis absorption spectrum of the dye prepared in n-decane in Example 4; Figure 9 This is a standard absorbance-concentration curve of the dye prepared in Example 4 in n-decane; Figure 10 The image shows the UV-Vis absorption spectrum of the dye prepared in n-decane in Example 6. Detailed Implementation

[0017] The present invention will be further described below through specific embodiments to enable those skilled in the art to better understand the present invention, but the present invention is not limited to the following embodiments.

[0018] Unless otherwise specified, the experimental methods described in the following examples are conventional methods; unless otherwise specified, the reagents and materials are commercially available.

[0019] Example 1: Preparation of dye BNDI-1.

[0020] The synthetic route for dye BNDI-1 is as follows: (Method 1);

[0021] Where G1 is 1, 4 The substituted phenyl group is: G2 and G3 are the same, both being phenyl; R1 and R2 are the same, both being 2-n-octyl-1-dodecyl; R3 and R4 are the same, both being H; R8 is H.

[0022] (1) Synthesis of intermediate 1: Under an argon atmosphere, 2,6-dibromonaphthalene-1,4,5,8-tetracarboxylic dianhydride (4.9660 g, 11.66 mmol), 2-n-octyl-1-dodecylamine (12.2512 g, 41.17 mmol), and glacial acetic acid (120 mL) were added to a 250 mL round-bottom flask and the mixture was heated under reflux for 3 h. After cooling to room temperature, the mixture was extracted with hexane and water. The organic phase was dried over anhydrous magnesium sulfate, filtered, and the solvent was removed by rotary evaporation. The crude product was purified by column chromatography (petroleum ether: dichloromethane = 1.5:1, v / v), and further purified by recrystallization (dichloromethane / methanol) to give intermediate 1 (6.4361 g) as a yellow solid, with a yield of 56.0%. 1 H NMR (600 MHz, CDCl3) δ: 8.97 (s, 2H), 4.13 (d, J = 7.8 Hz, 4H), 2.00 – 1.95 (m, 2H), 1.39 – 1.22 (m, 64H), 0.87 – 0.84 (m, 12H). This indicates that the target product, substance B, and compound IV-a were obtained. At this point, substance B is the same as substance C (compound IV-b).

[0023] (2) Synthesis of intermediate 2: Under an argon atmosphere, a mixture of intermediate 1 (0.3975 g, 0.40 mmol) (at which point substances B and C were identical, each 0.20 mmol), substance A p-phenylenediamine (0.0164 g, 0.15 mmol), potassium carbonate (0.0842 g, 0.61 mmol), and DMF (5 mL) was reacted at 80 °C for 24 h. After cooling to room temperature, the mixture was extracted with hexane and water. The organic phase was dried with anhydrous magnesium sulfate, filtered, and the solvent was removed by rotary evaporation. The mixture was then purified by recrystallization (dichloromethane / methanol) to give intermediate 2 (0.2791 g), a purple solid, in 96.0% yield. 1 H NMR (400 MHz, CDCl3) δ: 11.81 (s, 2H), 8.92 (s,2H), 8.63 (s, 2H), 7.53 (s, 4H), 4.15 (d, J = 7.2 Hz, 4H), 4.11 (d, J = 6.8Hz, 4H), 1.99 (br, 4H), 1.42 – 1.21 (m, 128H), 0.86 – 0.83 (m, 24H). This indicates that the target product was obtained.

[0024] (3) Synthesis of dye BNDI-1: Under an argon atmosphere, a mixture of intermediate 2 (0.2210 g, 0.12 mmol), D-aniline (0.1097 g, 1.18 mmol), and NMP (5 mL) was heated at 150 °C for 48 h. After cooling to room temperature, the mixture was extracted with hexane and water. The organic phase was dried with anhydrous magnesium sulfate, filtered, and the solvent was removed by rotary evaporation. The crude product was purified by column chromatography (petroleum ether: dichloromethane = 1.5:1, v / v), and further purified by recrystallization (dichloromethane / methanol) to obtain the blue dye BNDI-1 (0.1400 g), with a yield of 62.6%. 1 H NMR (600 MHz, CDCl3) δ: 11.17 (s, 2H), 11.15 (s, 2H), 8.67 (s, 2H), 8.49 (s, 2H), 7.54 (s, 4H), 7.47 (s, 4H), 7.42 (s, 4H), 7.30 –7.26 (m, 2H), 4.15 (s, 4H), 4.02 (s, 4H), 2.04 (s, 2H), 1.92 (s, 2H), 1.41 –1.21 (m, 128H), 0.87 – 0.82 (m, 24H) ( Figure 1This indicates that the target product was obtained.

[0025] Example 2: Preparation of dye BNDI-2.

[0026] The synthetic route for dye BNDI-2 is as follows: (Method 1);

[0027] Under an argon atmosphere, a mixture of intermediate 2 (0.1829 g, 0.10 mmol), p-methoxyaniline (0.1199 g, 0.97 mmol), and NMP (5 mL) obtained in Example 1 was heated at 150 °C for 48 h. After cooling to room temperature, the mixture was extracted with hexane and water. The organic phase was dried with anhydrous magnesium sulfate, filtered, and the solvent was removed by rotary evaporation. The crude product was purified by column chromatography (petroleum ether: dichloromethane = 1.7:1, volume ratio), and further purified by recrystallization (dichloromethane / methanol) to obtain the blue dye BNDI-2 (0.1180 g), with a yield of 61.8%. 1 H NMR (600 MHz, CDCl3) δ: 11.13 (s, 2H), 10.95 (s, 2H), 8.68 (s, 2H), 8.26 (s, 2H), 7.56 (s, 4H), 7.34 (d, J = 4.2 Hz, 4H), 7.00 (d, J = 7.8 Hz, 4H), 4.15 (s, 4H), 3.97 (s, 4H), 3.90 (s, 6H), 2.06– 2.02 (m, 2H), 1.88 (s, 2H), 1.43 – 1.20 (m, 128H), 0.89 – 0.82 (m, 24H)( Figure 2 This indicates that the target product was obtained.

[0028] Example 3: Preparation of dye BNDI-3.

[0029] The synthetic route for dye BNDI-3 is as follows: (Method 1);

[0030] Under an argon atmosphere, a mixture of intermediate 2 (0.9592 g, 0.50 mmol) obtained in Example 1, p-dodecylaniline (1.3109 g, 5.01 mmol), and NMP (5 mL) was heated at 150 °C for 48 h. After cooling to room temperature, the mixture was extracted with hexane and water. The organic phase was dried with anhydrous magnesium sulfate, filtered, and the solvent was removed by rotary evaporation. The crude product was purified by column chromatography (petroleum ether: dichloromethane = 4:1, volume ratio), and further purified by recrystallization (dichloromethane / methanol) to obtain the blue dye BNDI-3 (0.7200 g), with a yield of 63.2%. 1 H NMR (600 MHz, CDCl3) δ: 11.13 (s, 2H), 11.08 (s, 2H), 8.69 (s, 2H), 8.40 (s, 2H), 7.57 (s, 4H), 7.34 (s, 4H), 7.27 (s, 4H), 4.16 (s, 4H), 3.95 (s, 4H), 2.69 (s, 4H), 2.05 (s, 2H), 1.86 (s,2H), 1.71 (s, 4H), 1.42 – 1.20 (m, 164H), 0.90 (t, J = 7.2 Hz, 6H), 0.86 –0.82 (m, 24H) ( Figure 3 This indicates that the target product was obtained.

[0031] Example 4: Preparation of dye BNDI-4.

[0032] The synthetic route for dye BNDI-4 is as follows: (Method 1);

[0033] (1) Synthesis of intermediate 3: Under an argon atmosphere, a mixture of intermediate 1 (0.4926 g, 0.50 mmol), 1,4-naphthyldiamine (0.0319 g, 0.20 mmol), potassium carbonate (0.1120 g, 0.81 mmol), and DMF (5 mL) obtained in Example 1 was reacted at 80 °C for 24 h. After cooling to room temperature, the mixture was extracted with hexane and water. The organic phase was dried with anhydrous magnesium sulfate, filtered, and the solvent was removed by rotary evaporation. The crude product was purified by column chromatography (petroleum ether: dichloromethane = 1:1, volume ratio), and further purified by recrystallization (dichloromethane / methanol) to obtain purple solid intermediate 3 (0.2500 g), with a yield of 53.3%. 1H NMR (600 MHz, CDCl3) δ: 12.13 (s, 2H), 8.96 (s, 2H), 8.40 (s, 2H), 8.18 (dd, J = 6.6, 3.0Hz, 2H), 7.73 (s, 2H), 7.66 (dd, J = 6.6, 3.0 Hz, 2H), 4.23 (d, J = 7.2 Hz, 4H), 4.06 (d, J = 7.2 Hz, 4H), 2.10 – 2.06 (m, 2H), 1.94 – 1.90 (m, 2H), 1.46– 1.19 (m, 128H), 0.87 – 0.81 (m, 24H). This indicates that the target product was obtained.

[0034] (2) Synthesis of dye BNDI-4: Under an argon atmosphere, a mixture of intermediate 3 (0.2500 g, 0.13 mmol), p-dodecylaniline (0.3343 g, 1.28 mmol), and NMP (5 mL) was heated at 150 °C for 48 h. After cooling to room temperature, the mixture was extracted with hexane and water. The organic phase was dried over anhydrous magnesium sulfate, filtered, and the solvent was removed by rotary evaporation. The crude product was purified by column chromatography (petroleum ether: dichloromethane = 2:1, v / v), and further purified by recrystallization (dichloromethane / methanol) to give the blue dye BNDI-4 (0.1927 g), with a yield of 65.1%. 1 H NMR (600 MHz, CDCl3) δ: 11.51 (s, 2H), 11.03 (s, 2H), 8.56 – 8.53 (m, 2H), 8.44 (s, 2H), 8.17 (s, 2H), 7.82 (br, 2H), 7.57 (s, 2H),7.28 – 7.26 (m, 4H), 7.19 – 7.22 (m, 4H), 4.15 (s, 4H), 4.00 (s, 4H), 2.65(t, J = 7.2 Hz, 4H), 2.05 (s, 2H), 1.90 (s, 2H), 1.70 – 1.65 (m, 4H), 1.39 –1.18 (m, 164H), 0.91 – 0.89 (m, 6H), 0.87 – 0.80 (m, 24H) ( Figure 4 This indicates that the target product was obtained.

[0035] Example 5: Preparation of dye BNDI-4.

[0036] The synthetic route (II) for dye BNDI-4 is as follows: (Method II);

[0037] (1) Synthesis of intermediate 4: Under an argon atmosphere, a mixture of intermediate 1 (0.2961 g, 0.30 mmol) obtained in Example 1, p-dodecylaniline (0.0792 g, 0.30 mmol), potassium carbonate (0.0415 g, 0.30 mmol), and DMF (5 mL) was reacted at 150 °C for 8 h. After cooling to room temperature, the mixture was extracted with ethyl acetate and water. The organic phase was dried with anhydrous magnesium sulfate, filtered, and the solvent was removed by rotary evaporation. The crude product was purified by column chromatography (petroleum ether: dichloromethane = 1:1, volume ratio), and further purified by recrystallization (dichloromethane / methanol) to obtain purple solid intermediate 4 (0.0675 g), with a yield of 19.3%. 1 H NMR (600 MHz, CDCl3) δ: 11.67 (s, 1H), 8.88 (s, 1H), 8.53 (s, 1H), 7.30 (d, J = 8.4 Hz, 2H), 7.26 (d, J = 8.0 Hz, 2H), 4.14 (d, J = 7.2 Hz, 2H), 4.08 (d, J = 7.2 Hz, 2H), 2.67 (t, J = 7.8 Hz, 2H), 2.02 – 1.98 (m, 1H), 1.97 – 1.93 (m, 1H), 1.69– 1.65 (m, 2H), 1.43 – 1.22 (m, 82H), 0.90 – 0.84 (m, 15H). This indicates that the target product was obtained.

[0038] (2) Synthesis of dye BNDI-4: Under an argon atmosphere, a mixture of intermediate 4 (0.0675 g, 0.06 mmol), 1,4-naphthyldiamine (0.0032 g, 0.02 mmol), potassium carbonate (0.0028 g, 0.02 mmol), and NMP (5 mL) was reacted at 150 °C for 48 h. After cooling to room temperature, the mixture was extracted with hexane and water. The organic phase was dried with anhydrous magnesium sulfate, filtered, and the solvent was removed by rotary evaporation. The crude product was purified by column chromatography (petroleum ether: dichloromethane = 1:1, volume ratio), and further purified by recrystallization (dichloromethane / methanol) to obtain the blue dye BNDI-4. 1 The H NMR data are the same as in Example 4, indicating that the target product was obtained.

[0039] Example 6: Preparation of dye BNDI-5.

[0040] The synthetic route for dye BNDI-5 is as follows: (Method 1);

[0041] (1) Synthesis of intermediate 5: Under an argon atmosphere, a mixture of intermediate 1 (0.4925 g, 0.50 mmol), 1,5-naphthyldiamine (0.0320 g, 0.20 mmol), potassium carbonate (0.1104 g, 0.80 mmol), and DMF (5 mL) obtained in Example 1 was reacted at 80 °C for 24 h. After cooling to room temperature, the mixture was extracted with hexane and water. The organic phase was dried with anhydrous magnesium sulfate, filtered, and the solvent was removed by rotary evaporation. The crude product was purified by column chromatography (petroleum ether: dichloromethane = 1:1, volume ratio), and further purified by recrystallization (dichloromethane / methanol) to obtain purple solid intermediate 5 (0.2320 g), with a yield of 58.3%. 1 H NMR (600 MHz, CDCl3) δ: 12.13 (s, 2H), 8.94 (s, 2H), 8.40 (s, 2H), 8.14 (d, J = 8.4 Hz, 2H), 7.72 (d, J = 7.2 Hz, 2H), 7.67 (t, J = 7.8 Hz, 2H), 4.21 (d, J = 6.6 Hz, 4H), 4.06 (d, J= 7.2 Hz, 4H), 2.08 – 2.04 (m, 2H), 1.95 – 1.91 (m, 2H), 1.45– 1.20 (m, 128H), 0.87 – 0.82 (m, 24H). This indicates that the target product was obtained.

[0042] (2) Synthesis of dye BNDI-5: Under an argon atmosphere, a mixture of intermediate 5 (0.2320 g, 0.12 mmol), p-dodecylaniline (0.3084 g, 1.18 mmol), and NMP (5 mL) was heated at 150 °C for 48 h. After cooling to room temperature, the mixture was extracted with hexane and water. The organic phase was dried with anhydrous magnesium sulfate, filtered, and the solvent was removed by rotary evaporation. The crude product was purified by column chromatography (petroleum ether: dichloromethane = 1.5:1, v / v), and further purified by recrystallization (dichloromethane / methanol) to obtain the blue dye BNDI-5 (0.2065 g), with a yield of 75.2%. 1 H NMR (600 MHz, CDCl3) δ: 11.46 (s, 2H), 11.11 (s,2H), 8.48 (s, 2H), 8.11 (d, J = 7.2 Hz, 2H), 7.63 (s, 4H), 7.34 (s, 4H), 7.27– 7.25 (m, 6H), 4.08 (s, 4H), 4.04 (s, 4H), 2.68 (t, J = 6.0 Hz, 4H), 1.98(s, 2H), 1.96 (s, 2H), 1.73 – 1.68 (m, 4H), 1.43 – 1.20 (m, 164H), 0.90 (t, J = 6.6 Hz, 6H), 0.86 – 0.80 (m, 24H) ( Figure 5 This indicates that the target product was obtained.

[0043] Example 7: Preparation of dye BNDI-6.

[0044] The synthetic route for dye BNDI-6 is as follows: (Method 1);

[0045] (1) Synthesis of intermediate 6: Under an argon atmosphere, a mixture of intermediate 1 (0.4954 g, 0.50 mmol) obtained in Example 1, 1,4-cyclohexanediamine (0.0228 g, 0.20 mmol), potassium carbonate (0.1104 g, 0.80 mmol), and DMF (5 mL) was reacted at 80 °C for 24 h. After cooling to room temperature, the mixture was extracted with hexane and water. The organic phase was dried with anhydrous magnesium sulfate, filtered, and the solvent was removed by rotary evaporation. The crude product was purified by column chromatography (petroleum ether: dichloromethane = 1:2, volume ratio), and further purified by recrystallization (dichloromethane / methanol) to give red solid intermediate 6 (0.3233 g), with a yield of 84.2%. 1 H NMR (600 MHz, CDCl3) δ: 10.28 (d, J = 7.2 Hz, 2H), 8.88 – 8.84 (m, 2H), 8.28 (d, J = 7.8Hz, 2H), 4.13 (d, J = 6.0 Hz, 8H), 3.98 (s, 2H), 2.41 (d, J = 4.8 Hz, 4H), 1.99 (s, 4H), 1.86 – 1.80 (m, 4H), 1.42 – 1.22 (m, 128H), 0.87 – 0.84 (m, 24H). This indicates that the target product was obtained.

[0046] (2) Synthesis of dye BNDI-6: Under an argon atmosphere, a mixture of intermediate 6 (0.4500 g, 0.23 mmol), p-dodecylaniline (0.6120 g, 2.34 mmol), and NMP (5 mL) was heated at 150 °C for 48 h. After cooling to room temperature, the mixture was extracted with hexane and water. The organic phase was dried with anhydrous magnesium sulfate, filtered, and the solvent was removed by rotary evaporation. The crude product was purified by column chromatography (petroleum ether: dichloromethane = 1:1, volume ratio), and further purified by recrystallization (dichloromethane / methanol) to obtain the blue dye BNDI-6 (0.3688 g), with a yield of 69.0%. 1 H NMR (600 MHz, CDCl3) δ: 11.03 (s, 2H), 9.59 (d, J =7.2 Hz, 2H), 8.53 – 8.51 (m, 2H), 8.20 – 8.17 (m, 2H), 7.27 – 7.24 (m, 8H), 4.14 (d, J= 7.8 Hz, 4H), 4.09 (d, J = 7.8 Hz, 4H), 3.88 (s, 2H), 2.64 (t, J = 7.8 Hz, 4H), 2.39 (d, J = 7.2 Hz, 4H), 2.03 – 1.97 (m, 4H), 1.77 – 1.73 (m,4H), 1.68 – 1.63 (m, 4H), 1.41 – 1.22 (m, 164H), 0.90 – 0.83 (m, 30H) ( Figure 6 This indicates that the target product was obtained.

[0047] Example 8: Preparation of dye BNDI-7.

[0048] The synthetic route for dye BNDI-7 is as follows: (Method 3);

[0049] (1) Synthesis of intermediate 7: Under an argon atmosphere, intermediate 1 (0.2965 g, 0.30 mmol) obtained in Example 1 was subjected to... N A mixture of propylaniline (0.0415 g, 0.31 mmol), potassium carbonate (0.0615 g, 0.44 mmol), and DMF (5 mL) was reacted at 150 °C for 8 h. After cooling to room temperature, the mixture was extracted with ethyl acetate and water. The organic phase was dried over anhydrous magnesium sulfate, filtered, and the solvent was removed by rotary evaporation. The crude product was purified by column chromatography (petroleum ether: dichloromethane = 1:1, volume ratio), and further purified by recrystallization (dichloromethane / methanol) to give intermediate 7 (0.1964 g), a purple solid, in 62.8% yield. 1 H NMR (600 MHz, CDCl3) δ: 8.86 (s, 1H), 8.61 (s, 1H), 7.27 – 7.25 (m, 2H), 7.06 – 7.03 (m,3H), 4.12 (d, J = 7.2 Hz, 2H), 3.98 (t, J = 7.8 Hz, 2H), 3.94 (d, J= 7.2 Hz,2H), 2.01 – 1.97 (m, 1H), 1.78 – 1.72 (m, 2H), 1.50 (s, 1H), 1.42 – 1.08 (m,64H), 0.96 (t, J = 6.6 Hz, 3H), 0.87 – 0.84 (m, 12H). This indicates that the target product was obtained.

[0050] (2) Synthesis of intermediate 8: Under an argon atmosphere, a mixture of intermediate 7 (0.6800 g, 0.65 mmol), p-phenylenediamine (0.7070 g, 6.54 mmol), and NMP (30 mL) was heated at 150 °C for 48 h. After cooling to room temperature, the mixture was extracted with hexane and water. The organic phase was dried with anhydrous magnesium sulfate, filtered, and the solvent was removed by rotary evaporation. The crude product was purified by column chromatography (petroleum ether: dichloromethane = 1:4, volume ratio), and further purified by recrystallization (dichloromethane / methanol) to give a blue solid intermediate 8 (0.3500 g), with a yield of 50.2%. 1 H NMR (600 MHz, CDCl3) δ: 11.33 (s, 1H), 8.59 (s, 1H), 8.37 (s, 1H), 7.16 – 7.13 (m, 4H), 6.84 (d, J = 8.4 Hz, 2H), 6.79 (t, J = 7.2Hz, 1H), 6.74 (d, J = 8.4 Hz, 2H), 4.40 (br, 2H), 4.14 (d, J = 7.2 Hz, 2H), 3.93 (d, J = 7.2 Hz, 2H), 3.80 (t, J = 7.8 Hz, 2H), 2.04 – 2.00 (m, 1H), 1.79– 1.73 (m, 2H), 1.62 (s, 1H), 1.42 – 1.07 (m, 64H), 0.94 (t, J = 7.2 Hz, 3H), 0.87 – 0.84 (m, 12H). This indicates that the target product was obtained.

[0051] (3) Synthesis of intermediate 9: Under an argon atmosphere, a mixture of intermediate 1 (0.3238 g, 0.33 mmol), intermediate 8 (0.3500 g, 0.33 mmol), potassium carbonate (0.0454 g, 0.33 mmol), and DMF (10 mL) obtained in Example 1 was reacted at 150 °C for 8 h. After cooling to room temperature, the mixture was extracted with ethyl acetate and water. The organic phase was dried with anhydrous magnesium sulfate, filtered, and the solvent was removed by rotary evaporation. The crude product was purified by column chromatography (petroleum ether: dichloromethane = 1:1, volume ratio), and further purified by recrystallization (dichloromethane / methanol) to obtain a purple solid intermediate 9 (0.5374 g), with a yield of 83.1%. 1 H NMR (600 MHz, CDCl3) δ: 11.79 (s, 1H), 11.62 (s, 1H), 8.91 (s, 1H), 8.62 (s, 1H), 8.62 (s,1H), 8.60 (s, 1H), 7.54 – 7.50 (m, 4H), 7.17 (t, J = 7.8 Hz, 2H), 6.84 (t, J = 7.8 Hz, 1H), 6.81 (d, J = 7.8 Hz, 2H), 4.16 (d, J = 4.2 Hz, 4H), 4.11 (d, J = 7.2 Hz, 2H), 3.95 (d, J = 7.8 Hz, 2H), 3.85 (t, J = 6.6 Hz, 2H), 2.05 –2.01 (m, 2H), 1.99 – 1.97 (m, 1H), 1.81 – 1.75 (m, 2H), 1.62 (s, 1H), 1.43 –1.09 (m, 128H), 0.96 (t, J = 7.8 Hz, 3H), 0.87 – 0.82 (m, 24H). This indicates that the target product was obtained.

[0052] (4) Synthesis of dye BNDI-7: Under an argon atmosphere, a mixture of intermediate 9 (0.4700 g, 0.24 mmol), p-dodecylaniline (0.6235 g, 2.38 mmol), and NMP (5 mL) was heated at 150 °C for 48 h. After cooling to room temperature, the mixture was extracted with hexane and water. The organic phase was dried over anhydrous magnesium sulfate, filtered, and the solvent was removed by rotary evaporation. The crude product was purified by column chromatography (petroleum ether: dichloromethane = 2:1, v / v), and further purified by recrystallization (dichloromethane / methanol) to give the blue dye BNDI-7 (0.2811 g), with a yield of 51.3%. 1 H NMR (600 MHz, CDCl3) δ: 11.57 (s, 1H), 11.21 (s, 1H), 11.13 (s, 1H), 8.64 (s, 1H), 8.60 (s, 1H), 8.58 (s, 1H), 8.53 (s, 1H), 7.51(d, J = 8.4 Hz, 2H), 7.48 (d, J = 8.4 Hz, 2H), 7.28 (d, J = 3.0 Hz, 4H), 7.17(t, J = 7.8 Hz, 2H), 6.83 (t, J = 7.2 Hz, 1H), 6.80 (d, J = 8.4 Hz, 2H), 4.13(d, J = 7.2 Hz, 4H), 4.10 (d, J = 7.2 Hz, 2H), 3.95 (d, J = 7.2 Hz, 2H), 3.83(t, J = 7.2 Hz, 2H), 2.66 (t, J = 7.8 Hz, 2H), 2.04 – 1.96 (m, 3H), 1.81 –1.75 (m, 2H), 1.70 – 1.65 (m, 2H), 1.63 (s, 1H), 1.43 – 1.09 (m, 146H), 0.96(t, J = 7.2 Hz, 3H), 0.89 (t, J = 6.6 Hz, 3H), 0.88 – 0.82 (m, 24H) ( Figure 7 This indicates that the target product was obtained.

[0053] Comparative Example 1: The structure of the dye NDI-1 in this comparative example is as follows: Formula (NDI-1) The synthetic route for dye NDI-1 is as follows:

[0054] Under an argon atmosphere, a mixture of intermediate 1 (0.4932 g, 0.50 mmol), aniline (0.4782 g, 5.00 mmol), and NMP (22 mL) obtained in Example 1 was heated at 150 °C for 48 h. After cooling to room temperature, the mixture was extracted with hexane and water. The organic phase was dried with anhydrous magnesium sulfate, filtered, and the solvent was removed by rotary evaporation. The crude product was purified by column chromatography (petroleum ether: dichloromethane = 2:1, volume ratio), and further purified by recrystallization (dichloromethane / methanol) to obtain the blue dye NDI-1 (0.4900 g), with a yield of 97.1%. 1 H NMR (600 MHz, CDCl3) δ: 11.14 (s, 2H), 8.56 (s,2H), 7.46 (t, J = 7.8 Hz, 4H), 7.37 (d, J = 7.8 Hz, 4H), 7.28 (d, J = 7.2 Hz, 2H), 4.10 (d, J = 7.2 Hz, 4H), 2.00 – 1.96 (m, 2H), 1.39 – 1.21 (m, 64H), 0.87 – 0.83 (m, 12H). This indicates that the target product was obtained.

[0055] Example 9: Ink formulation and performance testing.

[0056] 0.0019 g, 0.0020 g, 0.0023 g, 0.0023 g, 0.0023 g, 0.0023 g, 0.0023 g, 0.0022 g, and 0.0010 g of the bis(naphthyl)imide and mono(naphthyl)imide dyes (i.e., BNDI-1 to BNDI-7 and NDI-1) prepared in Examples 1 to 4, Examples 6 to 8, and Comparative Example 1, respectively, were weighed and dissolved in 73.0 g of n-decane to prepare electrowetting inks Ink-1 to Ink-8; 0.0023 g of the dye (i.e., BNDI-4) prepared in Example 4 was weighed and dissolved in 75.6 g of n-tetane, 76.3 g of n-tetradecane, and 81.0 g of squalane, respectively, to prepare electrowetting inks Ink-9 to Ink-11. Its color was observed visually, and its maximum absorption wavelength (λ) was measured using ultraviolet-visible spectrophotometry (testing instrument: Shimadzu UV-2700 ultraviolet-visible spectrophotometer). max The molar absorptivity (ε) was calculated, and the solubility C (20℃, saturated solution method) and FoM = ε × C value were calculated. The test results are shown in Table 1. In addition, the UV-Vis absorption spectra of dyes BNDI-4 and BNDI-5 are shown in Table 1. Figure 8 , Figure 10 The molar absorptivity of dye BNDI-4 is calculated as follows: Figure 9 As shown.

[0057] Table 1 Ink Performance Test Results

[0058] As shown in Table 1, compared with the mononaphthalene diimide dye (NDI-1) in Comparative Example 1, the bisnaphthalene diimide blue dyes provided by this invention have a higher molar absorptivity, and the electrowetting display inks prepared with them exhibit a purer blue color. Meanwhile, the bisnaphthalene diimide dyes (BNDI-3 to BNDI-7) containing long alkyl aromatic amine side chains have excellent solubility in non-polar solvents, with FoM values ​​as high as 3 × 10⁻⁶. 3 The above is a further explanation. When the prepared ink was applied to an electrowetting display device, test results showed no backflow under constant voltage. Therefore, the dye described in this invention and the ink prepared therefrom have excellent application prospects in the field of electrowetting displays.

[0059] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. It should be noted that for those skilled in the art, several changes, substitutions and modifications can be made without departing from the concept of the present invention, and these changes, substitutions and modifications should all be included within the scope of protection of the present invention.

[0060] Matters not covered in this invention are common knowledge.

Claims

1. A bis(naphthyl)imide blue dye, characterized in that, The general chemical structural formula of this dye is shown in formula (I): Equation (I); In equation (I), G1 can be any of the following structural formulas: ； G2 and G3 are each independently selected from any of the following structural formulas: ； Among them, R1, R2, R5, R6, R7, R 11 R 12 Each is independently selected from straight-chain or branched alkyl groups of C1 to C30, R3, R4, R8, R9, R 10 Each is independently selected from H, C1 to C30 straight-chain or branched alkyl groups, and R9 and R 10 They are not both H.

2. The bis(naphthyl)imide blue dye as described in claim 1, characterized in that, The R1, R2, R5, R6, R7, R 11 R 12 It is a straight-chain or branched alkyl group from C1 to C24, with R3, R4, R8, R9, and R6 as the base groups. 10 It is a straight-chain or branched alkyl group of H, C1-C24, R9 and R 10 They are not both H.

3. The bis(naphthyl)imide blue dye as described in claim 1, characterized in that, The bis(naphthyl)imide blue dye is one of the formulas (BNDI-1) to (BNDI-7): Formula (BNDI-1), formula (BNDI-2), Formula (BNDI-3), Formula (BNDI-4), Formula (BNDI-5), formula (BNDI-6), Formula (BNDI-7).

4. The method for preparing bis(naphthyl)imide blue dye as described in claim 1, characterized in that, This method includes any one of the following three methods: Method 1 includes the following steps: S1: Under the protection of an inert gas and in the presence of a first base, substance A, substance B, and substance C are added to a first solvent and undergo a nucleophilic substitution reaction at 45–180°C for 2–36 h to obtain the compound shown in formula (II); substance B and substance C may be the same or different. Formula (II); Among them, substance A is the compound shown in formula (III), substance B is the compound shown in formula (IV-a), and substance C is the compound shown in formula (IV-b); H2N—G1—NH2 Formula (III); In equation (III), G1 is defined in the same way as G1 in equation (I) above; Formula (IV-a); Formula (IV-b); In equation (IV-a), R1 is defined the same as R1 in equation (I) above; in equation (IV-b), R2 is defined the same as R2 in equation (I) above. The molar ratio of substance A, substance B, substance C, and the first base is 1:(1-5):(1-5):(1-10); S2: Under inert gas protection, the compound shown in formula (II) and substance D are added to the second solvent and undergo a nucleophilic substitution reaction at 80-180°C for 8-60 h to obtain the bis(naphthalene)imide dye shown in formula (I); Wherein, substance D is the compound shown in formula (V); Y2—NH—X formula (V); In equation (V), the definition of Y2 is the same as the definition of G2 and G3 in the aforementioned equation (I), and the definition of X is the same as the definition of R3 and R4 in the aforementioned equation (I); The molar ratio of the compound shown in formula (II) to substance D is 1:(2-25); Alternatively, method two includes the following steps: S1: Under the protection of an inert gas and in the presence of a second base, substance B (or substance C) and substance D are added to a third solvent and undergo a nucleophilic substitution reaction at 45–180 °C for 2–36 h to obtain the compound shown in formula (VI-a) or (VI-b). Formula (VI-a); Formula (VI-b); In equation (VI-a), R1, R3, and G2 are defined the same as R1, R3, and G2 in equation (I) above; in equation (VI-b), R2, R4, and G3 are defined the same as R2, R4, and G3 in equation (I) above. The molar ratio of substance B (or substance C), substance D, and the second base is 1:(0.5-1.5):(0.5-5); S2: Under the protection of an inert gas and in the presence of a third base, substance A, along with the compound shown in formula (VI-a) and the compound shown in formula (VI-b) (which may be the same as or different from the compound shown in formula (VI-a)), are added to a fourth solvent and undergo a nucleophilic substitution reaction at 80–180 °C for 8–60 h to obtain the bis(naphthalene)imide dye shown in formula (I). The molar ratio of substance A, the compound shown in formula (VI-a), the compound shown in formula (VI-b), and the third base is 1:(1-5):(1-5):(1-10); Alternatively, method three includes the following steps: S1: Under the protection of an inert gas, the compound shown in formula (VI-a) and substance A are added to the fifth solvent and undergo a nucleophilic substitution reaction at 80-180°C for 8-60 h to obtain the compound shown in formula (VII). Equation (VII); In equation (VII), R1, R3, G1, and G2 are defined in the same way as R1, R3, G1, and G2 in equation (I) above. The molar ratio of the compound and substance A shown in formula (VI-a) is 1:(1~25); S2: Under the protection of an inert gas and in the presence of a fourth base, the compound shown in formula (VII) and substance C are added to the sixth solvent and undergo a nucleophilic substitution reaction at 45–180 °C for 2–36 h to obtain the compound shown in formula (VIII). Formula (VIII); In equation (VIII), R1, R2, R3, G1, and G2 are defined in the same way as R1, R2, R3, G1, and G2 in equation (I) above. The molar ratio of the compound shown in formula (VII), substance C, and the fourth base is 1:(1-5):(0.5-5); S3: Under inert gas protection, the compound shown in formula (VIII) and substance D are added to the seventh solvent and undergo a nucleophilic substitution reaction at 80-180°C for 8-60 h to obtain the bis(naphthalene)imide dye shown in formula (I); The molar ratio of the compound and substance D shown in formula (VIII) is 1:(1-25); The first, second, third, and fourth bases may be the same or different, and are at least one of sodium carbonate, potassium carbonate, cesium carbonate, and sodium tert-butoxide; The first, second, third, fourth, fifth, sixth, and seventh solvents may be the same or different, and are tetrahydrofuran, 1,4-dihydrofuran, etc. Dioxane, chloroform, toluene N , N Dimethylformamide (DMF) N At least one of methylpyrrolidone (NMP) and dimethyl sulfoxide.

5. The method for preparing bis(naphthyl)imide blue dye as described in claim 4, characterized in that, The preparation method of the compounds shown in formulas (IV-a) and (IV-b) above specifically includes the following steps: 2,6-Dibromonaphthalene-1,4,5,8-tetracarboxylic dianhydride (CAS No.: 83204-68-6) reacts with Y1—NH2 in the presence of glacial acetic acid to give the compound shown in formula (IV-a) or (IV-b). In Y1—NH2, the definition of Y1 is the same as the definitions of R1 and R2 in the aforementioned formula (I).

6. The method for preparing the bis(naphthyl)imide blue dye as described in claim 4, characterized in that, The inert gas is argon or nitrogen.

7. An ink, characterized in that, It contains the bis(naphthyl)imide blue dye as described in claim 1.

8. The ink as described in claim 7, characterized in that, The ink comprises 0.0010 to 30 parts by weight of the bis(naphthalimide) blue dye and 70 to 100 parts by weight of a nonpolar solvent; The nonpolar solvent is at least one of n-decane, n-dodecane, n-tridecane, n-tetradecane, n-hexadecane, squalane, fluorinated alkanes, and silanes.

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