Luminescent chiral agent, preparation method thereof and chiral nematic liquid crystal material
By designing a luminescent chiral agent with a reasonable structure and building a binary chiral luminescence system, the problems of many species and degradation of circular polarization luminescence performance in the existing ternary chiral luminescence system are solved, and efficient circular polarization luminescence performance and stability are achieved.
Patent Information
- Application Number
- CN202510321289.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-18
- Publication Date
- 2025-06-20
AI Technical Summary
There are many types of substances in the existing ternary chiral luminescence system, which leads to difficulty in system adjustment and excessive doping often leads to a degradation of circularly polarized luminescence performance.
A luminescent chiral agent is used, and its structural design avoids interference from chiral groups on the electronic structure of chromophores, and enhances interaction with liquid crystal molecules through specific functional groups and rod-like structures to construct a binary chiral luminescence system.
The types of substances in the chiral luminescence system are reduced, the orderly arrangement and stability of liquid crystal molecules are improved, and the circular polarization luminescence performance is improved. The circular polarization luminescence intensity can reach 2000 millides, the asymmetry factor can reach 0.30, and the luminescence wavelength range is expanded to achieve circular polarization luminescence in the entire color gamut.
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Figure CN120172947A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of circularly polarized luminescent materials, and particularly to a luminescent chiral agent, a preparation method thereof, and a chiral nematic liquid crystal material. Background Art
[0002] At present, circularly polarized luminescence in liquid crystal systems is mainly achieved by adding chiral agents to commercial achiral nematic liquid crystals to form cholesteric liquid crystals. However, most of these chiral agents do not emit light. Therefore, it is necessary to add or dope achiral dyes to the constructed cholesteric liquid crystals for luminescence, thereby constructing a ternary chiral luminescence system. However, most ternary chiral luminescence systems, namely: host (liquid crystal), guest (achiral dye), and chiral agent, often need to add a variety of substances, and will face various problems such as: mismatched molecular energy levels in the system, phase separation, inability to form liquid crystals, etc. The system is difficult to adjust, and this ternary chiral luminescence system often faces the problem of overall decline in circularly polarized luminescence performance caused by over-doping.
[0003] Therefore, the prior art still needs to be improved and developed. Summary of the Invention
[0004] Based on the above deficiencies of the prior art, the object of the present invention is to provide a luminescent chiral agent, a preparation method thereof, and a chiral nematic liquid crystal material, aiming to solve the problems that the existing ternary chiral luminescence system contains a large variety of substances and often has a decline in circularly polarized luminescence performance due to over-doping.
[0005] The technical solution of the present invention is as follows:
[0006] In the first aspect of the present invention, a luminescent chiral agent is provided, wherein the structural formula of the luminescent chiral agent is shown in Formula (I) or Formula (II):
[0007]
[0008] Wherein, R1 is -C n H 2n+1 , and n = 5 - 12.
[0009] Optionally, the luminescent chiral agent is selected from one of the following structures:
[0010]
[0011]
[0012] In the second aspect of the present invention, a preparation method of the luminescent chiral agent as described above in the present invention is provided, which includes the following steps:
[0013] Add biphenyldicarboxylic acid, R1-OH, N,N'-dicyclohexylcarbodiimide, and 4-dimethylaminopyridine to a first organic solvent to obtain a first mixed solution;
[0014] After reacting the first mixed solution at room temperature, a first product is obtained;
[0015] Add the first product, binaphthol, N,N'-dicyclohexylcarbodiimide, and 4-dimethylaminopyridine to a second organic solvent to obtain a second mixed solution;
[0016] After reacting the second mixed solution at room temperature, a second product is obtained;
[0017] Add the second product, rhodamine B, N,N'-dicyclohexylcarbodiimide, and 4-dimethylaminopyridine to a third organic solvent to obtain a third mixed solution;
[0018] After reacting the third mixed solution at room temperature, the luminescent chiral agent is obtained;
[0019] Among them, R1 is -C n H 2n+1 , n = 5 - 12, and the binaphthol is R-binaphthol or S-binaphthol.
[0020] Optionally, when the binaphthol is R-binaphthol, R1-OH is R-configuration R1-OH; when the binaphthol is S-binaphthol, R1-OH is S-configuration R1-OH.
[0021] Optionally, the molar ratio of the biphenyldicarboxylic acid, R1-OH, N,N'-dicyclohexylcarbodiimide, and 4-dimethylaminopyridine is 1:(1 - 2):(1.2 - 3):(0.1 - 0.5);
[0022] After reacting the first mixed solution at room temperature for 6 - 48 h, a first product is obtained.
[0023] Optionally, the molar ratio of the first product, binaphthol, N,N'-dicyclohexylcarbodiimide, and 4-dimethylaminopyridine is (0.5 - 1):1:(1.2 - 3):(0.1 - 0.5);
[0024] After reacting the second mixed solution at room temperature for 6 - 48 h, a second product is obtained.
[0025] Optionally, the molar ratio of the second product, rhodamine B, N,N'-dicyclohexylcarbodiimide, and 4-dimethylaminopyridine is 1:(0.5 - 2):(1.2 - 3):(0.1 - 0.5);
[0026] After reacting the third mixed solution at room temperature for 6 - 48 h, the luminescent chiral agent is obtained.
[0027] In a third aspect of the present invention, a chiral nematic liquid crystal material is provided, wherein the chiral nematic liquid crystal material comprises a nematic liquid crystal and a luminescent chiral agent, and the luminescent chiral agent is the luminescent chiral agent as described above in the present invention or the luminescent chiral agent prepared by using the preparation method as described above in the present invention.
[0028] Optionally, the molar ratio of the luminescent chiral agent to the nematic liquid crystal is (0.001 - 0.018):1.
[0029] Optionally, the chiral nematic liquid crystal material further comprises a non-chiral dye, and the molar ratio of the non-chiral dye to the nematic liquid crystal is (0.012 - 0.038):1.
[0030] Beneficial effects: The luminescent chiral agent provided by the present invention and the nematic liquid crystal can form a binary chiral luminescence system, reducing the types of substances in the chiral luminescence system and avoiding the problem of a large number of substances contained in the ternary chiral luminescence body. At the same time, the luminescent chiral agent and the nematic liquid crystal have good compatibility, which can keep the liquid crystal molecules in good ordered arrangement, so that the chiral nematic liquid crystal material formed by the two has good stability and circularly polarized luminescence performance. The circularly polarized luminescence intensity can reach 500 millidegrees (mdeg), and the dissymmetry factor can reach 0.07. At the same time, based on the liquid crystal system of the luminescent chiral agent and the nematic liquid crystal provided by the present invention, after introducing a non-chiral dye into it, not only does the problem of the decrease in circularly polarized luminescence performance caused by over-doping not occur, but on the contrary, the circularly polarized luminescence performance of the whole liquid crystal system is improved. The circularly polarized luminescence intensity can reach 2000 millidegrees, and the dissymmetry factor can reach 0.30. At the same time, the luminescence wavelength range of the liquid crystal system is effectively expanded, realizing circularly polarized luminescence in the full color gamut. Description of the Drawings
[0031] Figure 1 1H NMR spectrum of the luminescent chiral agent R1 in Example 1.
[0032] Figure 2 1H NMR spectrum of the luminescent chiral agent S1 in Example 2.
[0033] Figure 3 Polarizing microscope image of the chiral nematic liquid crystal material containing the luminescent chiral agent S1 and the nematic liquid crystal 5CB in Example 3.
[0034] Figure 4 Test result graph of circularly polarized luminescence of the chiral nematic liquid crystal material in Example 3.
[0035] Figure 5 Dissymmetry factor result graph of the chiral nematic liquid crystal material in Example 3.
[0036] Figure 6 Polarizing microscope image of the chiral nematic liquid crystal material containing the luminescent chiral agent S1 and the achiral dye NIA with a molar ratio of 3.0% to the molar number of the nematic liquid crystal 5CB in Example 4.
[0037] Figure 7 Circularly polarized luminescence spectrum of the chiral nematic liquid crystal material in Example 4.
[0038] Figure 8 Result diagram of the dissymmetry factor of the chiral nematic liquid crystal material in Example 4. Detailed implementation manners
[0039] The present invention provides a luminescent chiral agent, a preparation method thereof and a chiral nematic liquid crystal material. To make the purpose, technical solution and effect of the present invention clearer and more definite, the present invention is further described in detail below. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.
[0040] Unless otherwise defined, all technical terms and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present invention belongs. The terms used in the description of the present invention are only for the purpose of describing specific implementation manners and are not intended to limit the present invention.
[0041] If there are descriptions involving "first", "second", etc. in the embodiments of the present invention, such descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the quantity of the indicated technical features.
[0042] Based on various problems of the current ternary chiral luminescence system, the present invention proposes to construct cholesteric liquid crystal circularly polarized luminescence materials through luminescent chiral agents. However, at present, there are few reports on binary cholesteric liquid crystal systems composed of a host (liquid crystal) and a guest (luminescent chiral agent). There are mainly two reasons: First, there are few luminescent chiral agents and they have not been commercialized yet. The development of luminescent chiral agents is difficult. Connecting chiral groups and luminescent dyes together by covalent bonds is a challenging task, usually facing complex synthesis routes and difficult separation and purification. Moreover, traditional chromophores will cause the chiral induction ability to decline or even disappear after combining with chiral groups, and the luminescence performance will also be affected. Therefore, it is crucial to propose a new method to simultaneously accommodate luminescence and chirality. Second, luminescent chiral agents and liquid crystal molecules usually have different molecular structural properties. Liquid crystal molecules usually have high symmetry and the arrangement of molecular long axes, while luminescent chiral agents often have complex chiral structures. These structural differences may lead to mismatched intermolecular interactions, thus affecting their miscibility and distribution uniformity, and may form aggregates or phase separation, thereby affecting the optical properties of liquid crystal materials and even leading to a decrease in the stability of the luminescence system.
[0043] Based on this, an embodiment of the present invention also provides a luminescent chiral agent (which can also be called a luminescent chiral dopant, and it is a luminescent chiral agent based on a rhodamine skeleton). Among them, the structural formula of the luminescent chiral agent is shown in Formula (Ⅰ) or Formula (Ⅱ):
[0044]
[0045] Among them, R1 is -C n H 2n+1 , n = 5 - 12 (for example, R1 can be -C5H 11 , -C6H 13 , C7H 15 , C8H 17 , C9H 19 , C 10 H 21 , C 11 H 23 or C 12 H 25 ).
[0046] The luminescent chiral agent provided by the present invention and the nematic liquid crystal can form a binary chiral luminescent system, reducing the types of substances in the chiral luminescent system and avoiding the problem of a large number of substances contained in the ternary chiral luminescent body. At the same time, the luminescent chiral agent and the nematic liquid crystal have good compatibility, which can keep the liquid crystal molecules in good ordered arrangement. As a result, the chiral nematic liquid crystal material formed by the two has good stability and circularly polarized luminescence performance. The circularly polarized luminescence intensity can reach 500 millidegrees, and the dissymmetry factor can reach 0.07. At the same time, based on the liquid crystal system of the luminescent chiral agent and the nematic liquid crystal provided by the present invention, after introducing achiral dyes into it, not only does the problem of the decrease in circularly polarized luminescence performance caused by over-doping not occur, but on the contrary, the circularly polarized luminescence performance of the whole liquid crystal system is improved. The circularly polarized luminescence intensity can reach 2000 millidegrees (mdeg), and the dissymmetry factor (g lum ) can reach 0.30. At the same time, the luminescence wavelength range of the liquid crystal system is effectively expanded, realizing circularly polarized luminescence in the full color gamut.
[0047] In the embodiments of the present invention, the structural design of the luminescent chiral agent avoids the interference of chiral groups on the electronic structure of the chromophore, thereby ensuring its chiral induction ability. Further, the introduction of chiral groups does not destroy the conjugated system of the chromophore, but even forms a larger conjugated system with it, which helps to enhance the transmission of chiral signals. Furthermore, the luminescent chiral agent provided by the present invention has a rigid structure, which can fix the orientation of chiral groups, provide a stable chiral environment, and enhance the chiral induction ability. In the chiral nematic liquid crystal, the luminescent chiral agent promotes the effective transmission of chiral information through the dipole-dipole interaction with liquid crystal molecules, improving the dissymmetry factor.
[0048] In the present invention, by introducing specific functional groups, such as long-chain alkyl groups, into the molecular structure of the luminescent chiral agent, the van der Waals forces or hydrogen bonds and other non-covalent interactions between it and liquid crystal molecules can be enhanced. These interactions help to improve the compatibility between the two and ensure the uniformity of the mixture. By introducing a rod-like structure similar to liquid crystal molecules in the molecular design of the luminescent chiral agent, the compatibility in shape and size between the two is enhanced. This design helps the luminescent chiral agent to be evenly distributed in the liquid crystal matrix and avoid phase separation. Through the above strategies, the luminescent chiral agent provided by the present invention can achieve good interaction matching with liquid crystal molecules, ensure uniform distribution in the liquid crystal, avoid the formation of aggregates or phase separation. Thus, the luminescent chiral agent can better affect the arrangement of liquid crystal molecules through chiral induction, promote the formation of chiral liquid crystal phases, and achieve the expected optical properties and material stability.
[0049] The dissymmetry factor is abbreviated as g lum， g lum The apparent definition of g lum is g L = 2(IR ) / (I L +I R ), where I L and I R are the left-handed and right-handed luminescence intensities, respectively.
[0050] In some embodiments, the luminescent chiral agent is selected from one of the following structures:
[0051]
[0052] The embodiment of the present invention also provides a preparation method of the luminescent chiral agent as described above in the present invention, which includes the following steps:
[0053] S1. Add biphenyl dicarboxylic acid, R1-OH (R1 is -C n H 2n+1 , n = 5 - 12), N,N'-dicyclohexylcarbodiimide, and 4-dimethylaminopyridine to a first organic solvent to obtain a first mixture;
[0054] S2. After reacting the first mixture at room temperature (specifically, an esterification reaction), obtain a first product;
[0055] S3. Add the first product, binaphthol (the binaphthol is R-binaphthol or S-binaphthol), N,N'-dicyclohexylcarbodiimide, and 4-dimethylaminopyridine to a second organic solvent to obtain a second mixture;
[0056] S4. After reacting the second mixture at room temperature (specifically, an esterification reaction), obtain a second product;
[0057] S5. Add the second product, rhodamine B, N,N'-dicyclohexylcarbodiimide, and 4-dimethylaminopyridine to a third organic solvent to obtain a third mixture;
[0058] S6. After reacting the third mixture at room temperature (specifically, an esterification reaction), obtain the luminescent chiral agent.
[0059] The preparation method provided by the present invention is simple. By using the method provided by the present invention to prepare the luminescent chiral agent, the chiral induction ability will not decrease after the chromophore and the chiral group are combined.
[0060] In some embodiments, when the binaphthol is R-binaphthol, R1-OH is R-configuration R1-OH; when the binaphthol is S-binaphthol, R1-OH is S-configuration R1-OH.
[0061] In step S1, in some embodiments, in the first mixed solution, the molar ratio of diphthalic acid, R1-OH, N,N'-dicyclohexylcarbodiimide, and 4-dimethylaminopyridine is 1:(1-2):(1.2-3):(0.1-0.5), for example, it can be 1:1:1.2:0.1, 1:1:1.2:0.2, 1:1:1.2:0.5, 1:1.5:1.2:0.1, 1:1.5:1.2:0.2, 1:1.5:1.2:0.5, 1:2:1.2:0.1, 1:2:1.2:0.2, 1:2:1.2:0.5, 1:1:2:0.1, 1:1:2:0.2, 1:1:2:0.3, 1:1:2:0.5, 1:1:3:0.1, 1:1:3:0.2, or 1:1:3:0.5, etc.
[0062] In some embodiments, in the first mixed solution, the concentration of diphthalic acid is 0.05-0.5 mol / L, for example, it can be 0.05 mol / L, 0.1 mol / L, 0.2 mol / L, 0.3 mol / L, 0.4 mol / L, or 0.5 mol / L, etc.
[0063] In some embodiments, the first organic solvent includes at least one of dichloromethane and tetrahydrofuran, but is not limited thereto.
[0064] In step S2, in some embodiments, after reacting the first mixed solution at room temperature for 6-48 h, a first product is obtained. By way of example, the reaction time can specifically be 6 h, 7 h, 8 h, 9 h, 10 h, 12 h, 15 h, 18 h, 20 h, 22 h, 25 h, 28 h, 30 h, 32 h, 35 h, 38 h, 40 h, 42 h, 45 h, or 48 h, etc.
[0065] In step S3, in some embodiments, the molar ratio of the first product, binaphthol, N,N'-dicyclohexylcarbodiimide, and 4-dimethylaminopyridine is (0.5-1):1:(1.2-3):(0.1-0.5), for example, it can be 0.5:1:1.2:0.1, 0.5:1:1.2:0.5, 1:1:1.2:0.1, 1:1:1.2:0.5, 1:1:2:0.1, 1:1:2:0.3, or 1:1:3:0.5, etc.
[0066] In some embodiments, in the second solution, the concentration of binaphthol is 0.01-0.5 mol / L, for example, it can be 0.01 mol / L, 0.02 mol / L, 0.05 mol / L, 0.1 mol / L, 0.2 mol / L, 0.3 mol / L, 0.4 mol / L, or 0.5 mol / L, etc.
[0067] In some embodiments, the second organic solvent includes at least one of dichloromethane and tetrahydrofuran, but is not limited thereto.
[0068] In step S4, in some embodiments, after reacting the second mixture at room temperature for 6 to 48 h, a second product is obtained. By way of example, the reaction time can specifically be 6 h, 7 h, 8 h, 9 h, 10 h, 12 h, 15 h, 18 h, 20 h, 22 h, 25 h, 28 h, 30 h, 32 h, 35 h, 38 h, 40 h, 42 h, 45 h or 48 h, etc.
[0069] In step S5, in some embodiments, the molar ratio of the second product, rhodamine B, N,N'-dicyclohexylcarbodiimide and 4-dimethylaminopyridine is 1:(0.5 to 2):(1.2 to 3):(0.1 to 0.5), for example, it can be 1:0.5:1.2:0.1, 1:0.5:1.2:0.5, 1:2:1.2:0.1, 1:2:1.2:0.5, 1:1:2:0.2, 1:1:2:0.3 or 1:1:3:0.2, etc.
[0070] In some embodiments, in the third solution, the concentration of the second product is 0.05 to 0.5 mol / L, for example, it can be 0.05 mol / L, 0.1 mol / L, 0.2 mol / L, 0.3 mol / L, 0.4 mol / L or 0.5 mol / L, etc.
[0071] In some embodiments, the third organic solvent includes at least one of dichloromethane and tetrahydrofuran, but is not limited thereto.
[0072] In step S6, in some embodiments, after reacting the third mixture at room temperature for 6 to 48 h, the luminescent chiral agent is obtained. By way of example, the reaction time can specifically be 6 h, 7 h, 8 h, 9 h, 10 h, 12 h, 15 h, 18 h, 20 h, 22 h, 25 h, 28 h, 30 h, 32 h, 35 h, 38 h, 40 h, 42 h, 45 h or 48 h, etc.
[0073] The embodiment of the present invention further provides a chiral nematic liquid crystal material (i.e., a liquid crystal circularly polarized luminescence material), wherein the chiral nematic liquid crystal material includes a nematic liquid crystal and a luminescent chiral agent, and the luminescent chiral agent is the luminescent chiral agent as described above in the present invention or the luminescent chiral agent prepared by using the preparation method as described above in the present invention.
[0074] In this embodiment, the nematic liquid crystal and the luminescent chiral agent have good compatibility. The system composed of the nematic liquid crystal and the luminescent chiral agent can emit circularly polarized light and has a relatively high dissymmetry factor, which can reach 0.07. That is, the chiral nematic liquid crystal material composed of the nematic liquid crystal and the luminescent chiral agent has the property of circularly polarized luminescence. The circularly polarized luminescence intensity can reach 500 millidegrees, and the dissymmetry factor can reach 0.07.
[0075] In some embodiments, the chiral nematic liquid crystal material is composed of a nematic liquid crystal and a luminescent chiral agent. The molar ratio of the luminescent chiral agent to the nematic liquid crystal is (0.001 - 0.018):1, that is, the number of moles of the luminescent chiral agent accounts for 0.1% - 1.8% of the number of moles of the nematic liquid crystal. As an example, the molar ratio of the luminescent chiral agent to the nematic liquid crystal can be 0.001:1, 0.002:1, 0.003:1, 0.004:1, 0.005:1, 0.006:1, 0.007:1, 0.008:1, 0.009:1, 0.01:1, 0.011:1, 0.012:1, 0.013:1, 0.014:1, 0.015:1, 0.016:1, 0.017:1 or 0.018:1, etc. When the molar ratio of the luminescent chiral agent to the nematic liquid crystal is greater than 0.018:1, the circularly polarized luminescence intensity of the chiral nematic liquid crystal material will become weak or even disappear. When the molar ratio of the luminescent chiral agent to the nematic liquid crystal is less than 0.001:1, the circularly polarized luminescence intensity of the chiral nematic liquid crystal material will become weak.
[0076] In some embodiments, the chiral nematic liquid crystal material includes a nematic liquid crystal, a luminescent chiral agent and a non-chiral dye.
[0077] In this embodiment, although a non-chiral dye is introduced into the chiral nematic liquid crystal material, there is no phenomenon of decline in circularly polarized luminescence performance caused by over-doping. Instead, the overall circularly polarized luminescence performance is improved. The circularly polarized luminescence intensity can reach about 2000 millidegrees. At the same time, the luminescence wavelength range of the chiral nematic liquid crystal material is effectively expanded, realizing circularly polarized luminescence in the full color gamut. Especially in the green luminescence band, through the combination and synergistic effect of the luminescent chiral agent and the non-chiral dye, the dissymmetry factor can be significantly increased to 0.30. That is, the interaction between the luminescent chiral agent and the non-chiral dye significantly improves the circularly polarized luminescence performance of the material. And compared with the liquid crystal system with a lower dissymmetry factor of the traditional chiral agent, the present invention demonstrates higher circularly polarized luminescence performance. This chiral nematic liquid crystal material provides new ideas for liquid crystal materials in the fields of optoelectronics, display technology, etc.
[0078] In some embodiments, the molar ratio of the luminescent chiral agent to the nematic liquid crystal is (0.001 - 0.018):1, and the molar ratio of the achiral dye to the nematic liquid crystal is (0.012 - 0.038):1. By way of example, the molar ratio of the achiral dye to the nematic liquid crystal can be 0.012:1, 0.015:1, 0.018:1, 0.020:1, 0.022:1, 0.025:1, 0.028:1, 0.03:1, 0.032:1, 0.035:1, or 0.038:1, etc. When the molar ratio of the achiral dye to the nematic liquid crystal is greater than 0.038:1 or less than 0.012:1, the circularly polarized luminescence intensity of the chiral nematic liquid crystal material will become weaker.
[0079] In some embodiments, the nematic liquid crystal includes at least one of 4'-n-pentyl-4-cyanobiphenyl (5CB), 4'-n-hexyl-4-cyanobiphenyl (6CB), 4'-n-heptyl-4-cyanobiphenyl (7CB), 4'-n-octyl-4-cyanobiphenyl (8CB), and E7 (which is a mixed liquid crystal, the main component of which is cyanobiphenyl compounds and is a commercial material), but is not limited thereto.
[0080] In some embodiments, the achiral dye includes but is not limited thereto.
[0081] The present invention will be further described below through specific examples.
[0082] In the following examples, the meanings of some symbols in the synthesis route are as follows:
[0083] DCC: N,N'-dicyclohexylcarbodiimide;
[0084] DMAP: 4-dimethylaminopyridine;
[0085] DCM: dichloromethane.
[0086] Example 1
[0087] This example provides a preparation method for a luminescent chiral agent R1, and its synthesis route is as follows:
[0088]
[0089] The preparation method for the luminescent chiral agent R1 includes the following steps:
[0090] (a) 720 mg of biphenyl dicarboxylic acid, 930 mg of N,N'-dicyclohexylcarbodiimide, and 36 mg of 4-dimethylaminopyridine were dissolved in 10 mL of dichloromethane. Finally, 390 mg of R-2-octanol was added dropwise, and the mixture was stirred at room temperature for 48 hours. The solvent was evaporated, and the residue was purified by silica gel column chromatography to obtain 371 mg of Compound 1 with a yield of 35%.
[0091] (b) 371 mg of Compound 1, 324 mg of N,N'-dicyclohexylcarbodiimide, and 12.8 mg of 4-dimethylaminopyridine were dissolved in 8 mL of dichloromethane. Finally, 300 mg of R-binaphthol was added, and the mixture was stirred at room temperature for 48 hours. The solvent was evaporated, and the residue was purified by silica gel column chromatography to obtain 281 mg of Compound 2 with a yield of 43%.
[0092] (c) 281 mg of Compound 2, 139 mg of N,N'-dicyclohexylcarbodiimide, and 5.5 mg of 4-dimethylaminopyridine were dissolved in 8 mL of dichloromethane. Finally, 215 mg of rhodamine B was added, and the mixture was stirred at room temperature for 48 hours. The solvent was evaporated, and the residue was purified by silica gel column chromatography to obtain 121.8 mg of the luminescent chiral agent R1 with a yield of 25%.
[0093] The 1H NMR spectrum (500 MHz, CDCl3) of the luminescent chiral agent R1 is shown as Figure 1 follows. The 1H NMR data of the luminescent chiral agent R1 are as follows:
[0094] 1 H NMR (500 MHz, CDCl3): δ = 8.09 (d, J = 8.5 Hz, 2H), 8.04 (d, J = 9.0 Hz, 1H), 7.96 (d, J = 8.0 Hz, 1H), 7.83 (t, J = 9.0 Hz, 2H), 7.71 (t, J = 7.5 Hz, 1H), 7.55 - 7.53 (m, 3H), 7.52 - 7.46 (m, 3H), 7.43 - 7.39 (m, 3H), 7.35 (d, J = 8.5 Hz, 2H), 7.29 (d, J = 4.0 Hz, 2H), 7.23 - 7.18 (m, 2H), 7.17 - 7.13 (m, 2H), 6.95 (d, J = 9.5 Hz, 1H), 6.77 - 6.68 (m, 5H), 5.17 (td, J = 12.5, 6.0 Hz, 1H), 3.69 - 3.61 (m, 4H), 3.51 (q, J = 7.0 Hz, 4H), 1.77 - 1.71 (m, 1H), 1.65 - 1.58 (m, 1H), 1.43 - 1.37 (m, 2H), 1.35 - 1.32 (m, 9H), 1.30 - 1.27 (m, 6H), 1.21 (t, J = 7.0 Hz, 6H), 0.87 (t, J = 6.5 Hz, 3H).
[0095] Example 2
[0096] This example provides a preparation method of a luminescent chiral agent S1, and its synthetic route is as follows:
[0097]
[0098] The preparation method of the luminescent chiral agent S1 includes the following steps:
[0099] (a) Take 720 mg of biphenyl dicarboxylic acid, 930 mg of N,N'-dicyclohexylcarbodiimide, and 36 mg of 4-dimethylaminopyridine, dissolve them in 10 mL of dichloromethane, and finally add dropwise 390 mg of S-2-octanol. Stir at room temperature for 48 hours, evaporate the solvent, and purify by silica gel column to obtain 371 mg of compound 3, with a yield of 35%.
[0100] (b) Take 371 mg of compound 3, 324 mg of N,N'-dicyclohexylcarbodiimide, and 12.8 mg of 4-dimethylaminopyridine, dissolve them in 8 mL of dichloromethane, and finally add 300 mg of S-binaphthol. Stir at room temperature for 48 hours, evaporate the solvent, and purify by silica gel column to obtain 281 mg of compound 4, with a yield of 43%.
[0101] (c) Take 281 mg of compound 4, 139 mg of N,N'-dicyclohexylcarbodiimide, and 5.5 mg of 4-dimethylaminopyridine, dissolve them in 8 mL of dichloromethane, and finally add 215 mg of rhodamine B. Stir at room temperature for 48 hours, evaporate the solvent, and purify by silica gel column to obtain 121.8 mg of the luminescent chiral agent S1, with a yield of 25%. The nuclear magnetic resonance hydrogen spectrum (500 MHz, deuterated chloroform) of the luminescent chiral agent S1 is shown as Figure 2 shown, and the nuclear magnetic resonance hydrogen spectrum data of the luminescent chiral agent S1 are as follows:
[0102] 11H NMR(500MHz, CDCl3): δ = 8.09 (d, J = 8.5 Hz, 2H), 8.03 (d, J = 9.0 Hz, 1H), 7.96 (d, J = 8.0 Hz, 1H), 7.83 (t, J = 9.0 Hz, 2H), 7.71 (t, J = 7.5 Hz, 1H), 7.55 - 7.53 (m, 3H), 7.52 - 7.46 (m, 3H), 7.43 - 7.39 (m, 3H), 7.35 (d, J = 8.5 Hz, 2H), 7.29 (d, J = 4.0 Hz, 2H), 7.23 - 7.18 (m, 2H), 7.17 - 7.13 (m, 2H), 6.95 (d, J = 9.5 Hz, 1H), 6.77 - 6.68 (m, 5H), 5.17 (td, J = 12.5, 6.0 Hz, 1H), 3.69 - 3.61 (m, 4H), 3.51 (q, J = 7.0 Hz, 4H), 1.77 - 1.71 (m, 1H), 1.65 - 1.58 (m, 1H), 1.43 - 1.37 (m, 2H), 1.35 - 1.32 (m, 9H), 1.30 - 1.27 (m, 6H), 1.21 (t, J = 7.0 Hz, 6H), 0.87 (t, J = 6.5 Hz, 3H).
[0103] Example 3
[0104] This example provides a chiral nematic liquid crystal material with circularly polarized luminescence, which is composed of a luminescent chiral agent R1 (prepared in Example 1) and a nematic liquid crystal 5CB. The molar ratio of the luminescent chiral agent to the nematic liquid crystal 5CB is 1.2%.
[0105] This example also provides another chiral nematic liquid crystal material with circularly polarized luminescence, which is composed of a luminescent chiral agent S1 (prepared in Example 1) and a nematic liquid crystal 5CB. The molar ratio of the luminescent chiral agent S1 to the nematic liquid crystal 5CB is 1.2%. The microstructure of the chiral nematic liquid crystal material containing the luminescent chiral agent S1 at room temperature is as follows Figure 3 shown. It can be seen that the luminescent chiral agent S1 can form a cholesteric liquid crystal with the nematic liquid crystal 5CB, and the formed liquid crystal texture is a typical chiral fingerprint texture, which further provides support for the formation of an ordered helical arrangement.
[0106] The structural formula of the nematic liquid crystal 5CB is as follows
[0107]
[0108] Using light with a wavelength of 490 nm as the excitation wavelength, the above chiral nematic liquid crystal material was excited for circularly polarized luminescence (CPL) testing. The results are as shown in Figure 4 and Figure 5As shown, it can be seen that the luminescent chiral agent can form a cholesteric liquid crystal in the nematic liquid crystal 5CB and emit circularly polarized light. The circularly polarized luminescence intensity can reach about 500 millidegrees, indicating that the constructed binary chiral system forms an ordered helical arrangement and has a relatively high asymmetry factor, which can reach 0.07.
[0109] Example 4
[0110] This example provides three chiral nematic liquid crystal materials with circularly polarized luminescence, which are composed of the luminescent chiral agent R1 (prepared in Example 1), the nematic liquid crystal 5CB, and the achiral dye NIA. The molar fraction of the luminescent chiral agent R1 in the nematic liquid crystal 5CB is 1.2%, and the molar fractions of the achiral dye NIA in the nematic liquid crystal 5CB are 1.2%, 1.6%, and 3.0% respectively.
[0111] This example also provides three other chiral nematic liquid crystal materials with circularly polarized luminescence, which are composed of the luminescent chiral agent S1 (prepared in Example 1), the nematic liquid crystal 5CB, and the achiral dye NIA. The molar fraction of the luminescent chiral agent S1 in the nematic liquid crystal 5CB is 1.2%, and the molar fractions of the achiral dye NIA in the nematic liquid crystal 5CB are 1.2%, 1.6%, and 3.0% respectively. Among them, the microstructure of the chiral nematic liquid crystal material containing the luminescent chiral agent S1 and the achiral dye NIA with a molar fraction of 3.0% in the nematic liquid crystal 5CB at room temperature is as Figure 6 shown. It can be seen that by introducing the achiral dye NIA, a cholesteric liquid crystal can still be formed with the liquid crystal 5CB. By observing the texture, no phase separation occurs, and the formed liquid crystal texture is a typical chiral fingerprint texture, further providing support for the formation of an ordered helical arrangement.
[0112] The structural formula of the nematic liquid crystal 5CB is the same as that in Example 2, and the structural formula of the achiral dye NIA is:
[0113]
[0114] Using light with a wavelength of 360 nm as the excitation wavelength to excite the above chiral nematic liquid crystal materials for CPL testing, the results are as Figure 7 and Figure 8 shown. It can be seen that by introducing the achiral dye NIA, not only does the problem of overall decline in circularly polarized luminescence performance due to over-doping not occur, but on the contrary, the overall circularly polarized luminescence performance is improved, and at the same time, the luminescence wavelength range of the liquid crystal system is effectively expanded. The circularly polarized luminescence intensity can reach about 2000 millidegrees and has a relatively high asymmetry factor, which can reach 0.30, providing a new strategy for regulating the multi-component doping system. At the same time, it can be seen that by adjusting the content of the achiral dye, the luminescence intensity and asymmetry factor of the chiral nematic liquid crystal material can be regulated.
[0115] It should be understood that the application of the present invention is not limited to the above examples. For those of ordinary skill in the art, improvements or modifications can be made according to the above description, and all such improvements and modifications shall fall within the protection scope of the appended claims of the present invention.
Claims
1. A luminescent chiral agent, characterized in that: The structural formula of the luminescent chiral agent is shown in formula (I) or formula (II): Where R1 is -C n H 2n+1 , n=5~12.
2. The luminescent chiral agent according to claim 1, characterized in that: The luminescent chiral agent is selected from one of the following structures:
3. A method for preparing the luminescent chiral agent according to claim 1, characterized in that: The steps include: Adding biphenyl dicarboxylic acid, R1-OH, N,N'-dicyclohexylcarbodiimide and 4-dimethylaminopyridine into a first organic solvent to obtain a first mixed solution; After reacting the first mixed solution at room temperature, a first product is obtained; adding the first product, binaphthol, N,N'-dicyclohexylcarbodiimide and 4-dimethylaminopyridine into a second organic solvent to obtain a second mixed solution; After reacting the second mixed solution at room temperature, a second product is obtained; adding the second product, rhodamine B, N,N'-dicyclohexylcarbodiimide and 4-dimethylaminopyridine into a third organic solvent to obtain a third mixed solution; After reacting the third mixed solution at room temperature, the luminescent chiral agent is obtained; Where R1 is -C n H 2n+1 , n=5-12, and the binaphthol is R-binaphthol or S-binaphthol.
4. The preparation method according to claim 3, characterized in that: When the binaphthol is R-binaphthol, R1-OH is R-configuration R1-OH; when the binaphthol is S-binaphthol, R1-OH is S-configuration R1-OH.
5. The preparation method according to claim 3 or 4, characterized in that: The molar ratio of the biphenyl dicarboxylic acid, R1-OH, N,N'-dicyclohexylcarbodiimide and 4-dimethylaminopyridine is 1:(1-2):(1.2-3):(0.1-0.5); The first mixed solution is reacted at room temperature for 6 to 48 hours to obtain a first product.
6. The preparation method according to claim 3 or 4, characterized in that: The molar ratio of the first product, binaphthol, N,N'-dicyclohexylcarbodiimide and 4-dimethylaminopyridine is (0.5-1):1:(1.2-3):(0.1-0.5); The second mixed solution is reacted at room temperature for 6 to 48 hours to obtain a second product.
7. The preparation method according to claim 3 or 4, characterized in that: The molar ratio of the second product, rhodamine B, N,N'-dicyclohexylcarbodiimide and 4-dimethylaminopyridine is 1:(0.5-2):(1.2-3):(0.1-0.5); The third mixed solution is reacted at room temperature for 6 to 48 hours to obtain the luminescent chiral agent.
8. A chiral nematic liquid crystal material, characterized in that: The chiral nematic liquid crystal material comprises a nematic liquid crystal and a luminescent chiral agent, wherein the luminescent chiral agent is the luminescent chiral agent described in any one of claims 1 to 2 or a luminescent chiral agent prepared by the preparation method described in any one of claims 3 to 7.
9. The chiral nematic liquid crystal material according to claim 8, characterized in that: The molar ratio of the luminescent chiral agent to the nematic phase liquid crystal is (0.001-0.018):
1.
10. The chiral nematic liquid crystal material according to any one of claims 8 to 9, characterized in that: The chiral nematic liquid crystal material further includes a non-chiral dye, and the molar ratio of the non-chiral dye to the nematic liquid crystal is (0.012-0.038):1.