Luminescent liquid crystal raceme, chiral luminescent molecule and preparation method thereof

Abstract

The invention relates to a luminescent liquid crystal raceme, a chiral luminescent molecule and a preparation method thereof. The structural formula of the raceme of the light-emitting liquid crystal is shown as a formula (rac)-IV: # imgabs0 #, wherein R1 and R2 are independently selected from substituted or non-substituted alkyl. The luminescent liquid crystal raceme with the structural formula shown as the formula (rac)-IV has the nematic phase liquid crystal property at the room temperature. A small amount of single chiral isomer is added into a raceme of the luminescent liquid crystal with the nematic liquid crystal property at the room temperature, and the ee value of the raceme is slightly increased, so that the chiral luminescent liquid crystal with the chiral nematic liquid crystal property at the room temperature can be obtained. The use amount of the single chiral isomer is greatly reduced, so that the cost of forming the chiral liquid crystal is greatly reduced. The blue fluorescence emitted by the chiral light-emitting liquid crystal and the red fluorescence emitted by the doping system provided by the invention are circularly polarized light, and the circularly polarized light-emitting asymmetric factor of the doped red light can be up to 0.13.

Description

Technical Field

[0001] The present invention relates to the field of liquid crystal technology, and in particular to a luminescent liquid crystal racemate, a chiral luminescent molecule and a preparation method thereof. Background Art

[0002] There are two main ways to achieve circularly polarized luminescence through liquid crystal systems: first, doping chiral agents and non-chiral luminescent dyes into commercial non-chiral nematic liquid crystals (such as 5CB, E7, etc.); second, directly synthesizing chiral luminescent liquid crystals.

[0003] Among them, although chiral doping systems have been studied more, they often face problems such as a wide variety of additives, poor molecular matching, and easy phase separation of luminescent dyes, which makes the system complex and difficult to adjust. Chiral luminescent liquid crystals need to take into account the introduction of molecular chirality, liquid crystal properties, and luminescent properties, which makes molecular design difficult and thus less reported. In addition, existing chiral luminescent liquid crystals have the following problems: high phase transition temperature, resulting in a non-liquid crystal state at room temperature; composed of a single enantiomer of the compound, the cost is high; the circularly polarized luminescence asymmetry factor is low, usually 10 -2 Magnitude.

[0004] At present, patent CN118064161A discloses a chiral luminescent molecule with cyanodiarylethene as the luminescent parent core and alkylene cyclohexane as the chiral unit. However, the liquid crystal phase temperature of the chiral luminescent molecule is as high as 100 degrees Celsius, and it crystallizes at room temperature. The circular polarization luminescence asymmetry factor (g lum ) is only 2.1×10 -2 In addition, a pure chiral sample with a high ee value (ee>99%) is required to achieve the corresponding chiral optical properties, resulting in a large amount of a single enantiomer. The single enantiomer is obtained by chiral column separation, which is costly (>10,000 yuan / g).

[0005] Therefore, the existing technology still needs to be improved and developed. Summary of the invention

[0006] In view of the above-mentioned deficiencies in the prior art, the purpose of the present invention is to provide a luminescent liquid crystal racemate, a chiral luminescent molecule and a preparation method thereof, aiming to solve the problems of the existing chiral luminescent molecules using cyanodiarylethene as the luminescent mother core and alkylene cyclohexane as the chiral unit, such as high temperature in the liquid crystal phase interval, large amount of single enantiomer, and low circularly polarized luminescence asymmetry factor.

[0007] The technical solution of the present invention is as follows:

[0008] In a first aspect of the present invention, a light-emitting liquid crystal racemate is provided, wherein the light-emitting liquid crystal racemate is a racemic 1-(2-cyanophenylvinylphenyl)-4-alkylene cyclohexane compound, and the structural formula of the racemic 1-(2-cyanophenylvinylphenyl)-4-alkylene cyclohexane compound is shown in formula (rac)-IV:

[0009] Where R 1 , R 2 are independently selected from substituted or unsubstituted alkyl groups.

[0010] Optionally, the substituted or unsubstituted alkyl group is selected from at least one of alkyl groups having 1 to 12 carbon atoms.

[0011] In a second aspect of the present invention, a chiral luminescent molecule is provided, wherein the chiral luminescent molecule is a chiral 1-(2-cyanostyrylphenyl)-4-alkylenecyclohexane compound, which is a single enantiomer of the luminescent liquid crystal racemate described in the first aspect, and the chiral 1-(2-cyanostyrylphenyl)-4-alkylenecyclohexane compound has a structural formula as shown in formula (S)-IV or formula (R)-IV:

[0012]

[0013] Where R 1 , R 2 are independently selected from substituted or unsubstituted alkyl groups.

[0014] Optionally, the substituted or unsubstituted alkyl group is selected from at least one of alkyl groups having 1 to 12 carbon atoms.

[0015] The third aspect of the present invention provides a method for preparing the luminescent liquid crystal racemate of the present invention, which comprises the steps of:

[0016] The compound represented by formula 1 is reacted with phosphorus ylide in an organic solvent to obtain a racemate represented by formula (rac)-2;

[0017] The racemate represented by formula (rac)-2 is reacted with diisobutylaluminum hydride in an organic solvent to obtain the racemate represented by formula (rac)-3;

[0018] The racemate represented by formula (rac)-3 is reacted with a benzyl cyanide derivative and a base in an organic solvent to obtain a racemate 1-(2-cyanostyrylphenyl)-4-alkylenecyclohexane compound having a structural formula as represented by formula (rac)-IV, i.e., the luminescent liquid crystal racemate;

[0019] Where R 1 , R2 independently selected from substituted or unsubstituted alkyl;

[0020] The above reaction formula is as follows:

[0021]

[0022] A fourth aspect of the present invention provides a method for preparing the chiral luminescent molecule of the present invention, comprising the steps of:

[0023] The compound represented by formula 1 is reacted with phosphorus ylide in an organic solvent to obtain a racemate represented by formula (rac)-2;

[0024] The racemate represented by formula (rac)-2 is reacted with diisobutylaluminum hydride in an organic solvent to obtain the racemate represented by formula (rac)-3;

[0025] The racemate represented by formula (rac)-3 is separated by chiral column chromatography to obtain a pair of single chiral enantiomers (S)-3 and (R)-3;

[0026] Relative reaction of (S)-3 or (R)-3 with a benzyl cyanide derivative and a base in an organic solvent to obtain a chiral 1-(2-cyanostyrylphenyl)-4-alkylenecyclohexane compound having a structural formula as shown in formula (S)-IV or formula (R)-IV, i.e., the chiral luminescent molecule;

[0027] Where R 1 , R 2 independently selected from substituted or unsubstituted alkyl;

[0028] The above reaction formula is as follows:

[0029]

[0030] Optionally, the molar ratio of the compound represented by Formula 1 to the phosphorus ylide is 2:1-1:2;

[0031] The temperature for reacting the compound represented by formula 1 with phosphorus ylide in an organic solvent is -80-40°C, and the reaction time is 1-24 hours.

[0032] Optionally, the organic solvent used for the reaction of the compound represented by Formula 1 with phosphorus ylide is at least one of tetrahydrofuran, methyltetrahydrofuran, diethyl ether and dioxane.

[0033] Optionally, the molar ratio of the racemate represented by formula (rac)-2 to diisobutylaluminum hydride is 1:0.9-1:1.1;

[0034] The organic solvent used in the reaction of the racemate represented by formula (rac)-2 with diisobutylaluminum hydride is at least one of chloroform, dichloromethane and dibromoethane;

[0035] The temperature for reacting the racemate represented by formula (rac)-2 with diisobutylaluminum hydride in an organic solvent is -80-30°C, and the reaction time is 1-6 hours.

[0036] Optionally, the solvent system used for separation of the racemate represented by formula (rac)-3 by chiral column chromatography is n-hexane and ethanol, and the volume ratio of the two is 95:5 to 99.5:0.5;

[0037] The chiral column used for separation of the racemate represented by formula (rac)-3 by chiral column chromatography is at least one of AY and OY.

[0038] Optionally, the base reacting with (S)-3 or (R)-3 is at least one of sodium methoxide, sodium ethoxide, sodium hydroxide and piperidine.

[0039] Optionally, the organic solvent used for the reaction with (S)-3 or (R)-3 is at least one of methanol, ethanol and pyridine.

[0040] Optionally, the temperature for reacting (S)-3 or (R)-3 with a benzyl cyanide derivative and a base in an organic solvent is 40-120° C., and the reaction time is 6-48 hours.

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] Based on the above molecular design, the present invention removes a benzene ring from the cyanodiarylethene luminescent mother nucleus to obtain a luminescent liquid crystal racemate having nematic liquid crystal properties at room temperature as shown in formula (rac)-IV.

[0043] The present invention adds a small amount of a single chiral isomer (R)-IV or (S)-IV to a luminescent liquid crystal racemate having a nematic phase liquid crystal property at room temperature, such as a structural formula (rac)-IV, and slightly increases its ee value (the lowest can be 1% ee), thereby obtaining a chiral luminescent liquid crystal having a cholesteric phase (chiral nematic phase) liquid crystal property at room temperature. Since the amount of the single chiral isomer is greatly reduced (the lowest is only 1%), the cost of forming the chiral liquid crystal is reduced by nearly 100 times compared with the above-mentioned system.

[0044] The chiral luminescent liquid crystal provided by the present invention emits blue fluorescence under ultraviolet excitation. By doping a red light dye into the chiral luminescent liquid crystal, the system can be converted to emit red fluorescence under ultraviolet excitation through fluorescence resonance energy transfer. The blue fluorescence emitted by the chiral luminescent liquid crystal itself and the red fluorescence emitted by the doped system are both circularly polarized luminescence, and the circularly polarized luminescence asymmetry factor of the red light after doping can be as high as 0.13. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 It is a differential scanning calorimetry (DSC) chart of the luminescent liquid crystal racemate having the structural formula (rac)-IV.

[0046] Figure 2 It is a polarizing microscope (POM) image of the luminescent liquid crystal racemate having the structural formula (rac)-IV at 25°C.

[0047] Figure 3 POM diagram of chiral luminescent liquid crystal with 1% ee at 25℃.

[0048] Figure 4 POM diagram of chiral luminescent liquid crystal with 20% ee at 25℃.

[0049] Figure 5 This is the emission diagram of chiral luminescent liquid crystal under ultraviolet excitation.

[0050] Figure 6 : It is the emission diagram of the chiral luminescent liquid crystal after doping Nile red under ultraviolet excitation, wherein the dotted line refers to the emission diagram when the doping amount of Nile red is 0.1 mol%, and the solid line refers to the emission diagram when the doping amount of Nile red is 2.0 mol%.

[0051] Figure 7 This is the circularly polarized luminescence (CPL) diagram of chiral luminescent liquid crystal.

[0052] Figure 8 It is the CPL diagram after Nile Red is doped in the chiral luminescent liquid crystal, where the black dotted line refers to the CPL diagram when the ee of the system mainly composed of (S)-IV is 20%, the black solid line refers to the CPL diagram when the ee of the system mainly composed of (R)-IV is 20%, the green dotted line refers to the CPL diagram when the ee of the system mainly composed of (S)-IV is 1%, and the green solid line refers to the CPL diagram when the ee of the system mainly composed of (R)-IV is 1%.

[0053] Fig. 9 is the g of the chiral luminescent liquid crystal doped with Nile red lum The black dashed line refers to the g when the ee of the system dominated by (S)-IV is 20%. lum The black solid line refers to the g when the ee of the system dominated by (R)-IV is 20%. lumThe green dashed line refers to the g when the ee of the system dominated by (S)-IV is 1%. lum The green solid line refers to the g when the ee of the system dominated by (R)-IV is 1%. lum picture. DETAILED DESCRIPTION

[0054] The present invention provides a luminescent liquid crystal racemate, a chiral luminescent molecule and a preparation method thereof. To make the purpose, technical solution and effect of the present invention clearer and more specific, 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 intended to limit the present invention.

[0055] The embodiment of the present invention provides a light-emitting liquid crystal racemate, wherein the light-emitting liquid crystal racemate is a racemic 1-(2-cyanophenylvinylphenyl)-4-alkylene cyclohexane compound, and the structural formula of the racemic 1-(2-cyanophenylvinylphenyl)-4-alkylene cyclohexane compound is shown in Formula (rac)-IV:

[0056] Where R 1 , R 2 are independently selected from substituted or unsubstituted alkyl groups.

[0057] In one embodiment, the substituted or unsubstituted alkyl group is selected from at least one of alkyl groups having 1 to 12 carbon atoms.

[0058] The embodiment of the present invention provides a chiral luminescent molecule, wherein the chiral luminescent molecule is a chiral 1-(2-cyanostyrylphenyl)-4-alkylenecyclohexane compound, which is a single enantiomer of the luminescent liquid crystal racemate described in the embodiment of the present invention. The chiral 1-(2-cyanostyrylphenyl)-4-alkylenecyclohexane compound has a structural formula as shown in Formula (S)-IV or Formula (R)-IV:

[0059]

[0060] Where R 1 , R 2 are independently selected from substituted or unsubstituted alkyl groups.

[0061] Chiral luminescent liquid crystals are obtained by doping a small amount of chiral luminescent molecules into a luminescent liquid crystal racemate.

[0062] Compared with the chiral luminescent liquid crystal disclosed in the existing patent CN118064161A, the main improvements of the embodiment of the present invention include:

[0063] In order to solve the problem that the temperature of the liquid crystal phase interval of the existing chiral luminescent liquid crystal is higher than room temperature, the embodiment of the present invention removes a benzene ring in the cyanodiarylethene luminescent mother nucleus on the basis of the aforementioned molecular design to obtain a luminescent liquid crystal racemate with a structural formula as shown in formula (rac)-IV at room temperature having nematic phase liquid crystal properties.

[0064] In order to solve the problem of large amount of single enantiomer, in the embodiment of the present invention, a small amount of single chiral isomer (R)-IV or (S)-IV is added to the luminescent liquid crystal racemate having nematic phase liquid crystal properties at room temperature, such as the structural formula (rac)-IV, and its ee value is slightly increased (the lowest can be 1% ee), so that a chiral luminescent liquid crystal having cholesteric phase (chiral nematic phase) liquid crystal properties at room temperature can be obtained. Since the amount of single chiral isomer is greatly reduced (the lowest is only 1%), the cost of forming chiral liquid crystal is reduced by nearly 100 times compared with the above system.

[0065] In view of the problem that the circular polarization emission asymmetry factor of the existing chiral luminescent liquid crystal is low, the chiral luminescent liquid crystal provided in the embodiment of the present invention emits blue fluorescence under ultraviolet excitation. By doping a red light dye therein, the system can be converted to emit red fluorescence under ultraviolet excitation through fluorescence resonance energy transfer. The blue fluorescence emitted by the liquid crystal itself and the red fluorescence emitted by the doped system are both circularly polarized, and the circular polarization emission asymmetry factor of the red light after doping can be as high as 0.13.

[0066] In one embodiment, the substituted or unsubstituted alkyl group is selected from at least one of alkyl groups having 1 to 12 carbon atoms.

[0067] As an example, the chiral luminescent molecule is selected from one of the following structures or its enantiomers:

[0068]

[0069] The embodiment of the present invention provides a method for preparing the luminescent liquid crystal racemate as described above, which comprises the steps of:

[0070] The compound represented by formula 1 is reacted with phosphorus ylide in an organic solvent to obtain a racemate represented by formula (rac)-2;

[0071] The racemate represented by formula (rac)-2 is reacted with diisobutylaluminum hydride in an organic solvent to obtain the racemate represented by formula (rac)-3;

[0072] The racemate represented by formula (rac)-3 is reacted with a benzyl cyanide derivative and a base in an organic solvent to obtain a racemate 1-(2-cyanostyrylphenyl)-4-alkylenecyclohexane compound having a structural formula as represented by formula (rac)-IV, i.e., the luminescent liquid crystal racemate;

[0073] Where R 1 , R 2 independently selected from substituted or unsubstituted alkyl;

[0074] The above reaction formula is as follows:

[0075]

[0076] In one embodiment, the base reacting with the racemate represented by formula (rac)-3 is at least one of sodium methoxide, sodium ethoxide, sodium hydroxide and piperidine.

[0077] In one embodiment, the organic solvent used in the reaction with the racemate represented by formula (rac)-3 is at least one of methanol, ethanol and pyridine.

[0078] In one embodiment, the temperature for reacting the racemate represented by formula (rac)-3 with a benzyl cyanide derivative and a base in an organic solvent is 40-120°C (such as 40°C, 60°C, 80°C, 100°C, 120°C, etc.), and the reaction time is 6-48 hours (such as 6 hours, 12 hours, 24 hours, 30 hours, 40 hours, 48 ​​hours, etc.).

[0079] Details of other steps are given below and will not be introduced here.

[0080] The embodiment of the present invention provides a method for preparing a chiral luminescent molecule, which comprises the steps of:

[0081] The compound represented by formula 1 is reacted with phosphorus ylide in an organic solvent to obtain a racemate represented by formula (rac)-2;

[0082] The racemate represented by formula (rac)-2 is reacted with diisobutylaluminum hydride in an organic solvent to obtain the racemate represented by formula (rac)-3;

[0083] The racemate represented by formula (rac)-3 is separated by chiral column chromatography to obtain a pair of single chiral enantiomers (S)-3 and (R)-3;

[0084] Relative reaction of (S)-3 or (R)-3 with a benzyl cyanide derivative and a base in an organic solvent to obtain a chiral 1-(2-cyanostyrylphenyl)-4-alkylenecyclohexane compound having a structural formula as shown in formula (S)-IV or formula (R)-IV, i.e., the chiral luminescent molecule;

[0085] Where R 1 , R 2 independently selected from substituted or unsubstituted alkyl;

[0086] The above reaction formula is as follows:

[0087]

[0088] Chiral luminescent liquid crystals are obtained by doping a small amount of chiral luminescent molecules into a luminescent liquid crystal racemate.

[0089] In one embodiment, the molar ratio of the compound represented by Formula 1 to the phosphorus ylide is 2:1-1:2.

[0090] In one embodiment, the organic solvent used for the reaction of the compound represented by Formula 1 with phosphorus ylide is at least one of tetrahydrofuran, methyltetrahydrofuran, diethyl ether and dioxane.

[0091] In one embodiment, the temperature for reacting the compound of Formula 1 with phosphorus ylide in an organic solvent is -80-40°C (such as -80°C, -60°C, -40°C, -20°C, 0°C, 10°C, 20°C, 40°C, etc.), and the reaction time is 1-24 hours (such as 1 hour, 2 hours, 4 hours, 10 hours, 15 hours, 20 hours, 22 hours, 24 hours, etc.).

[0092] In one embodiment, the molar ratio of the racemate represented by formula (rac)-2 to diisobutylaluminum hydride is 1:0.9-1:1.1, such as 1:1.1.

[0093] In one embodiment, the organic solvent used for the reaction of the racemate represented by formula (rac)-2 with diisobutylaluminum hydride is at least one of chloroform, dichloromethane and dibromoethane.

[0094] In one embodiment, the temperature for reacting the racemate represented by formula (rac)-2 with diisobutylaluminum hydride in an organic solvent is -80-30°C (such as -80°C, -60°C, -40°C, -20°C, 0°C, 10°C, 20°C, 30°C, etc.), and the reaction time is 1-6 hours (such as 1 hour, 2 hours, 4 hours, 5 hours, 6 hours, etc.).

[0095] In one embodiment, the solvent system used for separation of the racemate represented by formula (rac)-3 by chiral column chromatography is n-hexane and ethanol, and the volume ratio of the two is 95:5 to 99.5:0.5.

[0096] In one embodiment, the chiral column used for separation of the racemate represented by formula (rac)-3 by chiral column chromatography is at least one of AY and OY.

[0097] In one embodiment, the base reacting with (S)-3 or (R)-3 is at least one of sodium methoxide, sodium ethoxide, sodium hydroxide, and piperidine.

[0098] In one embodiment, the organic solvent used for the reaction with (S)-3 or (R)-3 is at least one of methanol, ethanol, and pyridine.

[0099] In one embodiment, the reaction temperature of (S)-3 or (R)-3 with a benzyl cyanide derivative and a base in an organic solvent is 40-120°C (such as 40°C, 60°C, 80°C, 100°C, 120°C, etc.), and the reaction time is 6-48 hours (such as 6 hours, 12 hours, 24 hours, 30 hours, 40 hours, 48 ​​hours, etc.).

[0100] The present invention is further described in detail below through specific examples.

[0101] Example 1

[0102] The compound represented by formula 1 and phosphorus ylide were mixed in tetrahydrofuran at a molar ratio of 1.13:1, and reacted at -78°C for 12 hours to obtain a racemate represented by formula (rac)-2;

[0103] The racemate represented by formula (rac)-2 and diisobutylaluminum hydride are mixed in dichloromethane at a molar ratio of 1:1.1, and reacted at -40°C for 2 hours to obtain the racemate represented by formula (rac)-3;

[0104] The racemate represented by formula (rac)-3 was separated by chiral column chromatography using an AY chiral column, wherein the solvent system used was n-hexane and ethanol, and the volume ratio of the two was 98:2, to obtain a pair of monochiral enantiomers (S)-3 and (R)-3;

[0105] Respectively react (S)-3 or (R)-3 with a benzyl cyanide derivative and sodium hydroxide in ethanol at 80° C. for 24 hours to obtain a chiral luminescent molecule having a structural formula as shown in formula (S)-IV or formula (R)-IV;

[0106] The racemate represented by formula (rac)-3 is reacted with a benzyl cyanide derivative and sodium hydroxide in ethanol at 80° C. for 24 hours to obtain a luminescent liquid crystal racemate represented by formula (rac)-IV;

[0107] The above reaction formula is as follows:

[0108]

[0109] The luminescent liquid crystal racemate with the structural formula (rac)-IV is a nematic phase liquid crystal at room temperature and a liquid crystal phase interval below 26°C, see the attached Figure 1 (racemic DSC) and attached Figure 2 (racemate POM) shown.

[0110] A small amount of a single chiral isomer is added to the luminescent liquid crystal racemate shown in formula (rac)-IV The chiral luminescent liquid crystal is obtained. The chiral luminescent liquid crystal is a cholesteric phase liquid crystal at room temperature when the ee value is 1%-20%. Figure 3 (1%eePOM) with Figure 4 (20% eePOM).

[0111] Chiral luminescent liquid crystal has blue fluorescence emission under ultraviolet excitation, see attached Figure 5 shown.

[0112] After the chiral luminescent liquid crystal is doped with 0.1mol% or 2.0mol% Nile Red, it has red fluorescence emission under ultraviolet excitation, see attached Figure 6 shown.

[0113] The chiral luminescent liquid crystal has ultraviolet-excited blue circularly polarized luminescence when the ee value is 1% or 20%, see attached Figure 7 shown.

[0114] When the ee value of the chiral luminescent liquid crystal is 1%-20%, after doping with 0.1mol% or 2.0mol% Nile Red, it has red CPL under ultraviolet excitation, see attached Figure 8 (CPL) and attached Fig. 9 (g lum ) as shown.

[0115] It should be understood that the application of the present invention is not limited to the above examples. For ordinary technicians in this field, improvements or changes can be made based on the above description. All these improvements and changes should fall within the scope of protection of the claims attached to the present invention.

Claims

1. A luminescent liquid crystal racemate, characterized in that: The luminescent liquid crystal racemate is a racemic 1-(2-cyanophenylvinylphenyl)-4-alkylene cyclohexane compound, and the structural formula of the racemic 1-(2-cyanophenylvinylphenyl)-4-alkylene cyclohexane compound is shown in Formula (rac)-IV: Where R 1 , R 2 are independently selected from substituted or unsubstituted alkyl groups.

2. The luminescent liquid crystal racemate according to claim 1, characterized in that: The substituted or unsubstituted alkyl group is at least one selected from alkyl groups having 1 to 12 carbon atoms.

3. A chiral luminescent molecule, characterized in that: The chiral luminescent molecule is a chiral 1-(2-cyanostyrylphenyl)-4-alkylenecyclohexane compound, and the structural formula of the chiral 1-(2-cyanostyrylphenyl)-4-alkylenecyclohexane compound is as shown in Formula (S)-IV or Formula (R)-IV: Where R 1 , R 2 are independently selected from substituted or unsubstituted alkyl groups.

4. The chiral luminescent molecule according to claim 3, characterized in that: The substituted or unsubstituted alkyl group is at least one selected from alkyl groups having 1 to 12 carbon atoms.

5. A method for preparing the luminescent liquid crystal racemate according to any one of claims 1 to 2, characterized in that: Includes steps: The compound represented by formula 1 is reacted with phosphorus ylide in an organic solvent to obtain a racemate represented by formula (rac)-2; The racemate represented by formula (rac)-2 is reacted with diisobutylaluminum hydride in an organic solvent to obtain the racemate represented by formula (rac)-3; The racemate represented by formula (rac)-3 is reacted with a benzyl cyanide derivative and a base in an organic solvent to obtain a racemate 1-(2-cyanostyrylphenyl)-4-alkylenecyclohexane compound having a structural formula as represented by formula (rac)-IV, i.e., the luminescent liquid crystal racemate; Where R 1 , R 2 independently selected from substituted or unsubstituted alkyl; The above reaction formula is as follows:

6. A method for preparing a chiral luminescent molecule according to any one of claims 3 to 4, characterized in that: Includes steps: The compound represented by formula 1 is reacted with phosphorus ylide in an organic solvent to obtain a racemate represented by formula (rac)-2; The racemate represented by formula (rac)-2 is reacted with diisobutylaluminum hydride in an organic solvent to obtain the racemate represented by formula (rac)-3; The racemate represented by formula (rac)-3 is separated by chiral column chromatography to obtain a pair of single chiral enantiomers (S)-3 and (R)-3; Relative reaction of (S)-3 or (R)-3 with a benzyl cyanide derivative and a base in an organic solvent to obtain a chiral 1-(2-cyanostyrylphenyl)-4-alkylenecyclohexane compound having a structural formula as shown in formula (S)-IV or formula (R)-IV, i.e., the chiral luminescent molecule; Where R 1 , R 2 independently selected from substituted or unsubstituted alkyl; The above reaction formula is as follows:

7. The method according to claim 6, characterized in that The molar ratio of the compound represented by formula 1 to the phosphorus ylide is 2:1-1:2; The temperature for reacting the compound represented by formula 1 with phosphorus ylide in an organic solvent is -80-40°C, and the reaction time is 1-24 hours.

8. The method according to claim 6, characterized in that The organic solvent used for the reaction between the compound represented by formula 1 and phosphorus ylide is at least one of tetrahydrofuran, methyltetrahydrofuran, diethyl ether and dioxane.

9. The method according to claim 6, characterized in that The molar ratio of the racemate represented by formula (rac)-2 to diisobutylaluminum hydride is 1:0.9-1:1.1; The organic solvent used in the reaction of the racemate represented by formula (rac)-2 with diisobutylaluminum hydride is at least one of chloroform, dichloromethane and dibromoethane; The temperature for reacting the racemate represented by formula (rac)-2 with diisobutylaluminum hydride in an organic solvent is -80-30°C, and the reaction time is 1-6 hours.

10. The method according to claim 6, characterized in that The solvent system used for separation of the racemate represented by formula (rac)-3 by chiral column chromatography is n-hexane and ethanol, and the volume ratio of the two is 95:5 to 99.5:0.5; The racemate represented by the formula (rac)-3 is separated by chiral column chromatography using at least one of AY and OY; The base that reacts with (S)-3 or (R)-3 is at least one of sodium methoxide, sodium ethoxide, sodium hydroxide, and piperidine; The organic solvent used for the reaction with (S)-3 or (R)-3 is at least one of methanol, ethanol and pyridine; The temperature for reacting the (S)-3 or (R)-3 with the benzyl cyanide derivative and the base in an organic solvent is 40-120° C. and the reaction time is 6-48 hours.

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