Planar chiral [2.2]cyclophane compounds, methods of preparation and uses thereof

Abstract

The application belongs to the technical field of fluorescent materials, and particularly relates to a planar chiral [2.2] cyclophane compound, a preparation method and application thereof, including a planar chiral [2.2] cyclophane-4-(dicyanomethylene)-4H-pyrane compound having the structure of formula (I). The planar chiral [2.2] cyclophane compound is prepared, and white light organic circularly polarized luminescent solid materials are obtained by modulating the planar chiral [2.2] cyclophane compound under the assistance of an acid. The white light materials have the circularly polarized luminescent performance, the white light configuration method is simple, the planar chiral [2.2] cyclophane compound is convenient to purify, has a high yield, and has good optical stability, and the white circularly polarized luminescent material can be prepared. The technical problems of the prior art, such as a complex preparation process, high cost and difficulty in wide application of the planar chiral white circularly polarized luminescent material of the [2.2] cyclophane structure, are solved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of fluorescent materials, and particularly relates to a planar chiral [2.2] cyclophane compound, a preparation method and application thereof. BACKGROUND

[0002] Circularly polarized light (CPL) refers to a special polarization phenomenon, and refers to a phenomenon that chiral luminescent materials or achiral luminescent materials emit different left-handed or right-handed circularly polarized light in a chiral environment. CPL materials can directly emit CPL without using a circularly polarized filter, and are gradually becoming an important way to generate circularly polarized light, and show important application prospects in the fields of 3D display, information encryption, biological coding, asymmetric synthesis and photoelectric detection, and attract wide attention of scientists. The performance of the CPL material is mainly characterized by two important parameters of a luminescence asymmetry factor and a luminescence quantum efficiency, and it is a difficulty in the field to prepare a white light CPL material with high asymmetry factor and high luminescence efficiency.

[0003] [2.2] cyclophane (PCP) is a polycyclic aromatic hydrocarbon, which has strong electron-donating ability and a twisted benzene ring structure that can inhibit intermolecular π-π stacking, thereby improving the luminescent properties of the [2.2] cyclophane compound. Introducing the [2.2] cyclophane into a pyrylium and 4-(dicyanomethylene)-4H-pyrane structure can obtain two chiral fluorescent materials. The binary system doped PMMA solid film obtained by modulating the two chiral fluorescent materials under the assistance of an acid can emit nearly perfect white light. The white light material can be applied to a white-emitting CPL material, and has great application potential in the field of CPL materials. Therefore, the application provides a planar chiral [2.2] cyclophane compound, a preparation method and application thereof, so as to solve the problems of preparation of a planar chiral light functional organic compound and development of a high-efficiency CPL material in the prior art. The synthesis method is simple, and the purification is convenient, the yield is high, the stability is good, in addition, no metal catalysis or other expensive catalyst catalysis is needed, the cost is low, and the method is suitable for wide application. SUMMARY

[0004] The present application is directed to the technical problems existing in the preparation of the above-mentioned planar chiral photo-functional organic compounds and the development of high-efficiency CPL materials, and provides a planar chiral [2.2] cyclophane pyrylium and a planar chiral [2.2] cyclophane 4-(dicyanomethylene)-4H-pyrane and a preparation method thereof. The solid white emitting material is obtained by controlling the different proportions of the two compounds, and the white light emitting material has circularly polarized light emitting performance, so as to solve the problems of the preparation of the planar chiral photo-functional organic compounds and the development of high-efficiency CPL materials in the prior art. The synthesis method is simple, convenient to purify, high in yield and good in stability. In addition, the planar chiral [2.2] cyclophane compound and the preparation method thereof do not need metal catalysis or other expensive catalyst catalysis, are low in cost, and are suitable for wide application. In addition, the application of the planar chiral [2.2] cyclophane compound in white circularly polarized light emitting materials is also provided.

[0005] In order to achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows: a planar chiral [2.2] cyclophane compound, including a planar chiral [2.2] cyclophane-4-(dicyanomethylene)-4H-pyrane, has the structure of formula (I):

[0006]

[0007] In order to achieve the convenient preparation of the planar chiral [2.2] cyclophane 4-(dicyanomethylene)-4H-pyrane, a method for preparing the planar chiral [2.2] cyclophane compound is provided.

[0008] The planar chiral [2.2] cyclophane 4-(dicyanomethylene)-4H-pyrane is prepared from a planar chiral cyclophane pyrylium compound, and the (Rp) isomer of the planar chiral cyclophane pyrylium compound has the structure of formula (II):

[0009]

[0010] The (Sp) isomer has the structure of formula (III):

[0011]

[0012] Based on the above, when the preparation method of the present embodiment is used for preparation, the (Rp) isomer of the planar chiral [2.2] cyclophane-4-(dicyanomethylene)-4H-pyrane also has the structure of formula (I) as described above, and the (Sp) isomer has the structure of formula (IV):

[0013]

[0014] That is, a planar chiral cyclophanyl pyrylium compound, i.e., planar chiral 5-acetyl-4-hydroxy[2.2]cyclophane, is subjected to four-step reactions to obtain planar chiral [2.2]cyclophane-4-(dicyanomethylidene)-4H-pyrane, wherein the planar chiral 5-acetyl-4-hydroxy[2.2]cyclophane is one of (Rp)-5-acetyl-4-hydroxy[2.2]cyclophane and (Sp)-5-acetyl-4-hydroxy[2.2]cyclophane, and in the present embodiment, the planar chiral [2.2]cyclophane-4-(dicyanomethylidene)-4H-pyrane is prepared using the planar chiral cyclophanyl pyrylium compound of formula (II), and the synthesis route is as follows:

[0015]

[0016] The present application provides a method for preparing a planar chiral [2.2]cyclophane compound, which obtains planar chiral [2.2]cyclophane-4-(dicyanomethylidene)-4H-pyrane through four-step reactions, and as a preferred embodiment, comprises the following preparation steps:

[0017] S1: planar chiral 5-acetyl-4-hydroxy[2.2]cyclophane and ethyl acetate are taken in a molar ratio of 1:(1.2-1.5), a catalyst ① is added thereto, and condensation reaction is carried out at 100-120°C to obtain a first-step product;

[0018] S1.1: after the condensation reaction, ice water is added thereto, and the pH value of the reaction solution is adjusted to 6-7 using a hydrochloric acid solution with a concentration of 1.2 mol / L;

[0019] S1.2: the reaction solution treated in the step S1.1 is precipitated, and suction filtration, drying and purification are carried out to obtain the first-step product in the form of a yellow solid;

[0020] S2: the first-step product in the step S1 is taken, a catalyst ② is added thereto, and condensation reaction is carried out at 100-120°C to obtain a second-step product;

[0021] S2.1: after the condensation reaction, ice water is added thereto, and the pH value of the reaction solution is adjusted to 6-7 using a saturated sodium carbonate solution;

[0022] S2.2: the reaction solution treated in the step S2.1 is precipitated, and suction filtration, drying and purification are carried out to obtain the second-step product in the form of a yellow solid;

[0023] S3: the second-step product in the step S2 is taken, malononitrile is added thereto, the molar ratio of the second-step product and malononitrile is 1:(1.2-1.5), and a catalyst ③ is added, and condensation reaction is carried out at 120-140°C to obtain a third-step product;

[0024] S3.1: After the condensation reaction, distilled water is added thereto and stirring is carried out for 0.5 h;

[0025] S3.2: The reaction solution treated in S3.1 is precipitated, and suction filtration, drying and purification are carried out to obtain the third step product as a red solid;

[0026] S4: The third step product in S3 is taken, p-dimethylaminobenzaldehyde is added thereto, and a catalyst IV is added, and a condensation reaction is carried out at 120-140°C to obtain a fac-chiral [2.2] cyclophane-4-(dicyanomethylene)-4H-pyrane;

[0027] S4.1: After the condensation reaction, extraction is carried out with dichloromethane, and the solvent is removed by rotary evaporation;

[0028] S4.2: The reaction solution treated in S4.1 is precipitated, and suction filtration, drying and purification are carried out to obtain a fac-chiral [2.2] cyclophane-4-(dicyanomethylene)-4H-pyrane as a red solid.

[0029] As preferred, in S1, the condensation reaction is carried out in a solvent of tetrahydrofuran, the catalyst I is a sodium hydride tetrahydrofuran suspension, and the molar ratio of the catalyst I to the fac-chiral 5-acetyl-4-hydroxy[2.2]cyclophane is (4-5):1.

[0030] As preferred, in S2, the condensation reaction is carried out in a solvent of acetic acid, the catalyst II is acetic acid and concentrated sulfuric acid, and the molar ratio of the first step product to the concentrated sulfuric acid is 1:(0.02-0.06).

[0031] As preferred, in S3, the condensation reaction is carried out in a solvent of acetic anhydride, and the catalyst III is acetic anhydride.

[0032] As preferred, in S4, the condensation reaction is carried out in a solvent of toluene, and the catalyst IV is piperidine and acetic acid.

[0033] The present application also provides the use of the fac-chiral [2.2] cyclophane compound in the field of white circularly polarized luminescent materials, and as preferred, the use of the fac-chiral [2.2] cyclophane compound is characterized in that 5×10 -4 mol / L fac-chiral [2.2] cyclophane-4-(dicyanomethylene)-4H-pyrane 36 μL, 5×10 -3 mol / L fac-chiral cyclophane pyrone compound 30 μL and 5×10 -4 mol / L trifluoroacetic acid 540 μL are added to 2384 μL of dichloromethane solution to obtain a solution with white emission.

[0034] Compared with the prior art, the application has the advantages and positive effects that

[0035] 1、The face-chiral [2.2] cyclophane compound provided by the application has an emission wavelength of 616 nm and a fluorescence quantum yield of 4%, the preparation method of the face-chiral [2.2] cyclophane compound is simple in synthesis method, convenient in purification, high in yield and good in stability, does not need metal catalysis or other expensive catalysts for catalysis, is low in cost and suitable for wide application; for the application of the face-chiral [2.2] cyclophane compound prepared by the above method, a solid white emitting material is obtained by controlling the different proportions of two compounds, and the white light emitting material has circularly polarized light emitting performance, so as to solve the problems of preparation of the face-chiral light functional organic compound and development of high-efficiency CPL material in the prior art, specifically, the face-chiral cyclophane pyranone compound is excited by a UV light source to radiate light with a peak wavelength in the range of 470-500 nm, the face-chiral [2.2] cyclophane-4-(dicyanomethylene)-4H-pyrane emits light in the range of 550-760 nm through intramolecular fluorescence resonance energy transfer (FRET), and stable white emission is generated. The white light material has circularly polarized light emitting performance, the white light configuration method is simple, the face-chiral [2.2] cyclophane compound is convenient to purify, high in yield and good in optical stability, and the white circularly polarized light emitting material can be prepared. BRIEF DESCRIPTION OF DRAWINGS

[0036] In order to more clearly illustrate the technical solutions of the embodiments of the application, the following will briefly introduce the drawings needed to be used in the embodiment description. Obviously, the drawings in the following description are some embodiments of the application, and other drawings can also be obtained by those skilled in the art without any creative labor.

[0037] Figure 1 The nuclear magnetic resonance hydrogen spectrum of the face-chiral [2.2] cyclophane 4-(dicyanomethylene)-4H-pyrane provided by the application;

[0038] Figure 2 The nuclear magnetic resonance carbon spectrum of the face-chiral [2.2] cyclophane 4-(dicyanomethylene)-4H-pyrane provided by the application;

[0039] Figure 3 The fluorescence emission spectrum of the white light solution provided by the application;

[0040] Figure 4 The actual picture of the white light solution provided by the application;

[0041] Figure 5 The CIE coordinate diagram of the white light solution provided by the application;

[0042] Figure 6 The fluorescence emission spectrum of the white light PMMA film provided by the present application;

[0043] Figure 7 The white light PMMA film provided by the present application is shown in the figure;

[0044] Figure 8 The CIE coordinate diagram of the white light PMMA film provided by the present application;

[0045] Figure 9 Circularly polarized luminescence spectra of the enantiomeric [2.2] cyclophane derivative (Rp)-enantiomeric cyclophane pyrone compound and (Sp)-enantiomeric [2.2] cyclophane 4-(dicyanomethylene)-4H-pyrane and the enantiomeric [2.2] cyclophane derivative (Sp)-enantiomeric cyclophane pyrone compound and (Rp)-enantiomeric [2.2] cyclophane 4-(dicyanomethylene)-4H-pyrane through different proportion combinations.

[0046] Figure 10 Circularly polarized luminescence spectra of the enantiomeric [2.2] cyclophane derivative (Rp)-enantiomeric cyclophane pyrone compound and (Sp)-enantiomeric [2.2] cyclophane 4-(dicyanomethylene)-4H-pyrane and the enantiomeric [2.2] cyclophane derivative (Sp)-enantiomeric cyclophane pyrone compound and (Rp)-enantiomeric [2.2] cyclophane 4-(dicyanomethylene)-4H-pyrane through different proportion combinations. DETAILED DESCRIPTION

[0047] In order to enable a more complete understanding of the above-mentioned purposes, features and advantages of the present application, the present application will be further described below in conjunction with the accompanying drawings and examples. It should be noted that the examples of the present application and the features in the examples can be combined with each other without conflict.

[0048] In the following description, many specific details are set forth in order to provide a thorough understanding of the present application, however, the present application can also be practiced in other ways different from those described herein, therefore, the present application is not limited to the specific examples disclosed in the following description.

[0049] Example 1, an enantiomeric [2.2] cyclophane compound, including the Rp isomer of enantiomeric [2.2] cyclophane-4-(dicyanomethylene)-4H-pyrane has a structure as shown in formula (I), which has the structure of formula (I):

[0050]

[0051] The Sp isomer has a structure as shown in formula (II):

[0052]

[0053] In order to achieve the convenient preparation of the facially chiral [2.2] cyclophane 4-(dicyanomethylidene)-4H-pyrane, a method for preparing a facially chiral [2.2] cyclophane compound is provided:

[0054] That is, the facially chiral cyclophane pyrone compound, i.e., the facially chiral 5-acetyl-4-hydroxy[2.2]cyclophane, is subjected to four-step reactions to obtain the facially chiral [2.2] cyclophane-4-(dicyanomethylidene)-4H-pyrane, wherein the facially chiral 5-acetyl-4-hydroxy[2.2]cyclophane is one of (Rp)-5-acetyl-4-hydroxy[2.2]cyclophane and (Sp)-5-acetyl-4-hydroxy[2.2]cyclophane. In this embodiment, taking the preparation of the facially chiral [2.2] cyclophane 4-(dicyanomethylidene)-4H-pyrane of formula (I) as an example, the synthesis route is as follows:

[0055]

[0056] Of course, the above facially chiral cyclophane pyrone compound and the preparation method are prior art and have been described in the following document

Dyes and Pigments, 2022, 205, 110491.

[0057] In this embodiment, the four-step reactions described above to obtain the facially chiral [2.2] cyclophane-4-(dicyanomethylidene)-4H-pyrane include the following preparation steps:

[0058] S1: Take the facially chiral 5-acetyl-4-hydroxy[2.2]cyclophane and ethyl acetate in a molar ratio of 1:(1.2-1.5), and add catalyst ① to it, and carry out condensation reaction at 100-120℃ to obtain the first-step product;

[0059] In order to ensure the effective preparation of the first-step product, in the S1 step, the condensation reaction is carried out in a solvent of tetrahydrofuran, and the condensation reaction time is 10-20 min, and the catalyst ① is a sodium hydride tetrahydrofuran suspension, wherein the sodium hydride is pretreated with n-hexane; further, the molar ratio of the catalyst ① to the facially chiral 5-acetyl-4-hydroxy[2.2]cyclophane is (4-5):1; during the adjustment of the pH value of the reaction solution after the condensation reaction, hydrochloric acid solution can be used, and the concentration of the hydrochloric acid solution is 1.0-1.4 mol / L, to ensure that the condensation product is precipitated in the S1 step, and the precipitated product is in the form of yellow solid, and then the precipitated yellow solid is subjected to the steps of suction filtration, drying and purification, wherein the drying is carried out in a vacuum drying box, and the purification is carried out by silica gel column chromatography separation using petroleum ether / dichloromethane (1:1) as the developing agent;

[0060] S2: Take the first step product in S1 step, and add catalyst ② to it, and carry out condensation reaction at 100-120℃ to obtain the second step product;

[0061] In order to ensure the convenient preparation of the second step product, in S2 step: the condensation reaction is carried out in acetic acid as solvent, and the reaction time of the condensation reaction is 0.5-1h; further, catalyst ② is acetic acid and concentrated sulfuric acid, and the molar ratio of the first step product to concentrated sulfuric acid is 1:(0.02-0.06); the pH value of the reaction solution after the condensation reaction is adjusted to ensure the precipitation of the condensation product in S2 step, and the precipitated product is yellow solid, and then the precipitated yellow solid is subjected to the steps of suction filtration, drying and purification, wherein the drying is carried out in a vacuum drying box, and the purification is carried out by silica gel column chromatography separation using petroleum ether / dichloromethane (1:1) as the developing agent;

[0062] S3: Take the second step product in S2 step, add malononitrile to it, and the molar ratio of the second step product to malononitrile is 1:(1.2-1.5), and add catalyst ③, and carry out condensation reaction at 120-140℃ to obtain the third step product;

[0063] In order to ensure the convenient preparation of the third step product, in S3 step: catalyst ③ is acetic anhydride, the condensation reaction is carried out in acetic anhydride as solvent, and the reaction time of the condensation reaction is 10-14h; after the condensation reaction, distilled water is added and stirred for 0.5h to ensure the precipitation of the condensation product in S3 step, and the precipitated product is red solid; then the precipitated red solid is subjected to the steps of suction filtration, drying and purification, wherein the drying is carried out in a vacuum drying box, and the purification is carried out by silica gel column chromatography separation using petroleum ether / dichloromethane (1:1) as the developing agent.

[0064] S4: Take the third step product in S3 step, add p-dimethylaminobenzaldehyde to it, and add catalyst ④, and carry out condensation reaction at 120-140℃ to obtain chiral [2.2] cyclophane-4-(dicyanomethylene)-4H-pyrane;

[0065] In order to ensure the effective preparation of the facially chiral [2.2] cyclophane-4-(dicyanomethylene)-4H-pyrane, in the S4 step: the third step product and p-dimethylaminobenzaldehyde are reacted in a molar ratio of 1:(1.1-1.5), the catalyst (IV) selected is piperidine and acetic acid; the condensation reaction is carried out in toluene as the solvent, the condensation reaction time is 12-16 h, after the condensation reaction, dichloromethane is added for extraction, and the solvent is removed by rotary evaporation, wherein the obtained facially chiral [2.2] cyclophane compound is in the form of a red solid, and then the red solid is subjected to the steps of suction filtration, drying, and purification, wherein the drying is performed in a vacuum drying box, and the purification is performed by silica gel column chromatography separation using a developing agent of petroleum ether / dichloromethane in a volume ratio of 1:3.

[0066] The facially chiral [2.2] cyclophane 4-(dicyanomethylene)-4H-pyrane prepared by the above preparation method has an emission wavelength of 616 nm and a fluorescence quantum yield of 4%. The CIE coordinates of the prepared white light solution are (0.32, 0.33), and the CIE coordinates of the PMMA film doped white light material are (0.33, 0.32). In addition, the synthesis method of the preparation method is simple, the purification is convenient, the yield is high, the stability is good, and in addition, no metal catalyst or other expensive catalyst is required, the cost is low, and it is suitable for wide application.

[0067] The above specific reaction process is described as follows:

[0068] (1) The facially chiral 5-acetyl-4-hydroxy[2.2]cyclophane is protected by nitrogen, anhydrous tetrahydrofuran is added to dissolve it, ethyl acetate is then added, and then a catalyst is added, and the condensation reaction is carried out at 110°C for 15 minutes to obtain a reaction solution.

[0069] The catalyst is a sodium hydride tetrahydrofuran suspension, and the sodium hydride is pre-cleaned with n-hexane three times. Further, the molar ratio of the catalyst to the facially chiral 5-acetyl-4-hydroxy[2.2]cyclophane is 4.5:1, and the molar ratio of the facially chiral 5-acetyl-4-hydroxy[2.2]cyclophane to ethyl acetate is 1:1.4.

[0070] (2) Ice water is added to the reaction solution obtained in step (1) to adjust the pH value to 7.5 to precipitate the product, and the precipitated product is in the form of a yellow solid. The pH value of the reaction solution is adjusted using a 1.2 mol / L hydrochloric acid solution.

[0071] (3) The product precipitated in step (2) is subjected to suction filtration, drying, and purification, wherein the drying is performed in a vacuum drying box, and the purification is performed by column chromatography purification, and the silica gel column chromatography separation is performed using a developing agent of petroleum ether / dichloromethane in a volume ratio of 1:1.

[0072] (4) Take the separation product in step (3) and protect it with nitrogen, add acetic acid to dissolve it, then add a catalyst to it and stir for 1 hour to obtain a reaction solution; wherein the catalyst is concentrated sulfuric acid, and the molar ratio of the catalyst to the product of step (3) is 0.04:1.

[0073] (5) Add ice water to the reaction solution obtained in step (4) and adjust the pH value to 7.5 to precipitate the product, and the precipitated product is in the form of yellow solid, wherein the pH value of the reaction solution is adjusted by using saturated sodium carbonate solution.

[0074] (6) The product precipitated in step (5) is subjected to suction filtration, drying and purification, wherein the drying is performed in a vacuum drying box, and the purification is performed by column chromatography purification, and the silica gel column chromatography separation is performed by using a developing agent of petroleum ether / dichloromethane with a volume ratio of 1:1.

[0075] (7) Take the separation product in step (6) and protect it with nitrogen, add acetic anhydride to dissolve it, then add malononitrile to it, and perform a condensation reaction at 130°C for 12 hours to obtain a reaction solution; wherein the molar ratio of the product of step (6) to malononitrile is 1:1.4.

[0076] (8) Add water to the reaction solution obtained in step (7) and distill for 0.5 hours to precipitate the product, and the product is subjected to suction filtration, drying and purification, wherein the drying is performed in a vacuum drying box, and the purification is performed by column chromatography purification, and the silica gel column chromatography separation is performed by using a developing agent of petroleum ether / dichloromethane with a volume ratio of 1:1.

[0077] (9) Take the separation product in step (8) and protect it with nitrogen, add anhydrous toluene to dissolve it, then add 4-dimethylaminobenzaldehyde to it, and then add a catalyst to it, and perform a condensation reaction at 130°C for 14 hours to obtain a reaction solution; wherein the catalyst is a solution of piperidine and acetic acid with equal volume, the molar ratio of the catalyst to the separation product in step (8) is 0.03:1, and the molar ratio of the separation product in step (8) to 4-dimethylaminobenzaldehyde is 1:1.3.

[0078] It should be noted that in step (1), when the facially chiral 5-acetyl-4-hydroxy[2.2]cyclophane is (Rp)-5-acetyl-4-hydroxy[2.2]cyclophane, the facially chiral [2.2]cyclophane 4-(dicyanomethylidene)-4H-pyran obtained is the Rp isomer; when the facially chiral 5-acetyl-4-hydroxy[2.2]cyclophane is (Sp)-5-acetyl-4-hydroxy[2.2]cyclophane, the facially chiral [2.2]cyclophane 4-(dicyanomethylidene)-4H-pyran obtained is the Sp isomer.

[0079] Example 2: The preparation of the present example of the facially chiral [2.2] cyclophane 4-(dicyanomethylidene)-4H-pyran is identical to Example 1, except that in step (1) the molar ratio of catalyst to the facially chiral 5-acetyl-4-hydroxy[2.2]cyclophane is 4:1, the molar ratio of the facially chiral 5-acetyl-4-hydroxy[2.2]cyclophane to the ethyl acetate is 1:1.2, in step (4) the molar ratio of catalyst to the product of step (3) is 0.02:1, in step (7) the molar ratio of the product of step (6) to the malononitrile is 1:1.2, and in step (9) the molar ratio of catalyst to the isolated product of step (8) is 0.01:1, and the molar ratio of the isolated product of step (8) to the 4-dimethylaminobenzaldehyde is 1:1.1.

[0080] The preparation of the present example of the facially chiral [2.2] cyclophane 4-(dicyanomethylidene)-4H-pyran is identical to Example 1, except that in step (1) the molar ratio of catalyst to the facially chiral 5-acetyl-4-hydroxy[2.2]cyclophane is 4:1, the molar ratio of the facially chiral 5-acetyl-4-hydroxy[2.2]cyclophane to the ethyl acetate is 1:1.2, in step (4) the molar ratio of catalyst to the product of step (3) is 0.02:1, in step (7) the molar ratio of the product of step (6) to the malononitrile is 1:1.2, and in step (9) the molar ratio of catalyst to the isolated product of step (8) is 0.01:1, and the molar ratio of the isolated product of step (8) to the 4-dimethylaminobenzaldehyde is 1:1.1.

[0081] The molar ratio of catalyst to the facially chiral 5-acetyl-4-hydroxy[2.2]cyclophane in step (1) is 4:1, the molar ratio of the facially chiral 5-acetyl-4-hydroxy[2.2]cyclophane to the ethyl acetate is 1:1.2, the molar ratio of catalyst to the product of step (3) in step (4) is 0.02:1, the molar ratio of the product of step (6) to the malononitrile in step (7) is 1:1.2, and the molar ratio of catalyst to the isolated product of step (8) in step (9) is 0.01:1, and the molar ratio of the isolated product of step (8) to the 4-dimethylaminobenzaldehyde is 1:1.1.

[0082] Example 3: The preparation of the present example of the facially chiral [2.2] cyclophane 4-(dicyanomethylidene)-4H-pyran is identical to Example 1, except that the Rp isomer of the facially chiral [2.2] cyclophane 4-(dicyanomethylidene)-4H-pyran has the structure shown in Formula (I) and the Sp isomer has the structure shown in Formula (II).

[0083] The preparation of the present example of the facially chiral [2.2] cyclophane 4-(dicyanomethylidene)-4H-pyran is identical to Example 1, except that in step (1) the molar ratio of catalyst to the facially chiral 5-acetyl-4-hydroxy[2.2]cyclophane is 4:1, the molar ratio of the facially chiral 5-acetyl-4-hydroxy[2.2]cyclophane to the ethyl acetate is 1:1.2, in step (4) the molar ratio of catalyst to the product of step (3) is 0.02:1, in step (7) the molar ratio of the product of step (6) to the malononitrile is 1:1.2, and in step (9) the molar ratio of catalyst to the isolated product of step (8) is 0.01:1, and the molar ratio of the isolated product of step (8) to the 4-dimethylaminobenzaldehyde is 1:1.1.

[0084] Example 4: The preparation of the present example of the facially chiral [2.2] cyclophane 4-(dicyanomethylidene)-4H-pyran is identical to Example 1, except that the Rp isomer of the facially chiral [2.2] cyclophane 4-(dicyanomethylidene)-4H-pyran has the structure shown in Formula (I) and the Sp isomer has the structure shown in Formula (II).

[0085] The preparation method of the facially chiral [2.2]cyclophane 4-(dicyanomethylene)-4H-pyrane of the present example is the same as that of Example 1, with the exception that in steps (1), (4), (7) and (9), no nitrogen protection is used.

[0086] Example 5: The facially chiral [2.2]cyclophane 4-(dicyanomethylene)-4H-pyrane of the present example is the same as that of Example 1, with the Rp isomer of the facially chiral [2.2]cyclophane 4-(dicyanomethylene)-4H-pyrane having the structure shown in Formula (I) and the Sp isomer having the structure shown in Formula (II).

[0087] The preparation method of the facially chiral [2.2]cyclophane 4-(dicyanomethylene)-4H-pyrane of the present example is the same as that of Example 1, with the exception that in step (9), the catalyst is one of piperidine and acetic acid, and the molar ratio of the catalyst to the product separated and precipitated is 0.1:1.

[0088] To verify the technical effects of the facially chiral [2.2]cyclophane compounds obtained by the preparation method provided in the present example, the following tests were performed:

[0089] I. Proton nuclear magnetic resonance spectrum

[0090] The facially chiral [2.2]cyclophane 4-(dicyanomethylene)-4H-pyrane obtained in Examples 1-5 was determined by nuclear magnetic resonance to have the hydrogen spectrum shown in Figure 1 which is the hydrogen spectrum of the facially chiral [2.2]cyclophane compound, and in the hydrogen spectrum of the facially chiral [2.2]cyclophane compound: 1 H NMR (500 MHz, CDC13) δ 7.63 (d, J = 15.7 Hz, 1H), 7.56 (d, J = 8.5 Hz, 2H), 6.88 (s, 1H), 6.82 (d, J = 7.7 Hz, 1H), 6.76 (d, J = 7.9 Hz, 3H), 6.72 (d, J = 15.7 Hz, 1H), 6.67 (dd, J = 7.9, 1.9 Hz, 1H), 6.62 (dd, J = 7.9, 1.9 Hz, 1H), 6.25 (dd, J = 7.9, 1.9 Hz, 1H), 6.13 (dd, J = 7.9, 1.9 Hz, 1H), 3.71 - 3.65 (m, 1H), 3.60 (ddd, J = 15.3, 9.6, 6.1 Hz, 1H), 3.42 (ddd, J = 14.1, 9.6, 3.3 Hz, 1H), 3.29 - 3.22 (m, 1H), 3.09 (s, 6H), 3.08 - 3.03 (m, 2H), 2.85 (dddd, J = 37.2, 13.5, 10.1, 6.4 Hz, 2H).

[0091] II. Carbon nuclear magnetic resonance spectrum

[0092] The resolvent facially chiral [2.2] cyclophane 4-(dicyanomethylidene)-4H-pyrane obtained in Example 1-5 was determined by nuclear magnetic resonance to be carbon spectrum as shown in Figure 2 , which is the carbon spectrum of the facially chiral [2.2] cyclophane compound, in the carbon spectrum of the facially chiral [2.2] cyclophane compound: 13 C NMR (126 MHz, CDCI3) δ 157.0, 155.0, 152.7, 151.9, 141.4, 139.4, 139.3, 139.0, 139.0, 133.6, 132.2, 131.7, 129.9, 129.9, 127.6, 127.3, 122.6, 118.9, 117.0, 116.1, 113.5, 112.1, 105.3, 64.1, 40.2, 36.3, 35.7, 34.1, 31.3.

[0093] III. Preparation experiment of white light emitting material

[0094] The facially chiral [2.2] cyclophane 4-(dicyanomethylidene)-4H-pyrane prepared in Experimental Example 1 was dissolved in dichloromethane solution to prepare a 5 x 10 -4 mol / L solution, and according to the description in the existing literature, the facially chiral cyclophane pyrone compound was prepared and dissolved in dichloromethane solution to prepare a 5 x 10 -3 mol / L solution, and trifluoroacetic acid was dissolved in dichloromethane solution to prepare a 5 x 10 -4 mol / L solution.

[0095] 5 x 10 -4 mol / L facially chiral [2.2] cyclophane 4-(dicyanomethylidene)-4H-pyrane 36 μL, 5 x 10 -3 mol / L facially chiral cyclophane pyrone compound 30 μL, and 5 x 10 -4 mol / L trifluoroacetic acid 540 μL were added to 2384 μL of dichloromethane solution to obtain a white emitting solution.

[0096] The fluorescence spectrum signal and the white light real object diagram of the solution were determined according to the above method, as shown in Figure 3 , Figure 4 , and the CIE light coordinate diagram is shown in Figure 5 , wherein 1a is the facially chiral cyclophane pyrone compound, and 1b is the facially chiral [2.2] cyclophane 4-(dicyanomethylidene)-4H-pyrane.

[0097] 5 x 10 -4mol / L of the chiral [2.2] cyclophane 4-(dicyanomethylidene)-4H-pyran 36 μL, 5 x 10 -3 mol / L of the chiral cyclophane pyranone compound 30 μL, 5 x 10 -4 mol / L of trifluoroacetic acid 1000 μL was added into the dichloromethane solution of PMMA with a concentration of 10 mg / mL, and the solvent was evaporated to obtain a white-emitting PMMA film.

[0098] The fluorescence spectrum signal and the white light real object diagram of the PMMA film were measured according to the above method, as shown in Figure 6 Figure 7 The CIE light coordinate diagram is shown in Figure 8

[0099] Specifically, the chiral [2.2] cyclophane 4-(dicyanomethylidene)-4H-pyran has strong and stable fluorescence emission in dichloromethane solution, and a solution with white light emission can be obtained by adding the chiral cyclophane pyranone compound and trifluoroacetic acid in a certain proportion, that is, a solid PMMA material with white circularly polarized light emission can be obtained by different proportions.

[0100] Four, circularly polarized luminescence spectrum experiment of white light material

[0101] The circularly polarized luminescence spectrum of the above PMMA film was measured by a circularly polarized fluorescence spectrometer, wherein the measurement conditions of the spectrum data are as follows: the excitation wavelength is 375 nm.

[0102] Figure 9 Figure 10 The circularly polarized luminescence data of the PMMA white light film of the chiral [2.2] cyclophane 4-(dicyanomethylidene)-4H-pyran and the chiral cyclophane pyranone compound according to different chiral isomer configurations, wherein 1a is the chiral cyclophane pyranone compound, and 1b is the chiral [2.2] cyclophane 4-(dicyanomethylidene)-4H-pyran;

[0103] Specifically, the chiral cyclophane pyranone compound is excited by a UV light source to emit light with a peak wavelength in the range of 470-500 nm, and the chiral [2.2] cyclophane-4-(dicyanomethylidene)-4H-pyran emits light in the range of 550-760 nm through intramolecular fluorescence resonance energy transfer (FRET), resulting in stable white emission. The white light material has circularly polarized luminescence performance, and the white light configuration method is simple. The chiral [2.2] cyclophane compound is easy to purify, has high yield, and has good optical stability, and can be prepared into a white circularly polarized luminescent material. ​​​​

[0104] V. Enantiomeric [2.2]Cyclophane 4-(Dicyanomethylidene)-4H-pyran Yield

[0105] The preparation of enantiomeric [2.2]Cyclophane 4-(Dicyanomethylidene)-4H-pyran was carried out according to the preparation method in Examples 1-5, respectively, and after it was separated, it was weighed and the separation yield was calculated, and the calculation results are shown in Table 1 below:

[0106] Table 1 Yield calculation results:

[0107] Group Yield (%) Example 1 43 Example 2 40 Example 3 37 Example 4 21 Example 5 27

[0108] The above description is merely preferred embodiments of the present application, but not a limitation of the present application. Any modification, equivalent variation or improvement made by any person skilled in the art based on the above disclosed technical contents, which does not depart from the technical solution of the present application, shall fall within the scope of protection of the present application.

Claims

1. A chiral [2.2]cyclic aromatic compound, characterized in that, Compounds including chiral [2.2] cycloaryl-4-(dicyanomethylene)-4H-pyran having the structure of formula (I):

2. The method for preparing planar chiral [2.2] cyclic aromatic compounds according to claim 1, characterized in that, A four-step reaction yielded a chiral [2.2]cycloaryl-4-(dicyanomethylene)-4H-pyran, comprising the following preparation steps: S1: Take a chiral 5-acetyl-4-hydroxy[2.2]cycloaryl compound and ethyl acetate in a molar ratio of 1:(1.2-1.5), add catalyst ①, and carry out a condensation reaction at 100-120℃ to obtain the first step product; S1.1: After the condensation reaction, add ice water and adjust the pH of the reaction solution to 6-7 using a 1.2 mol / L hydrochloric acid solution; S1.2: The reaction solution after step S1.1 is precipitated, filtered, dried and purified to obtain the first product as a yellow solid; S2: Take the product from step S1, add catalyst ② to it, and carry out a condensation reaction at 100-120℃ to obtain the product from step S2. S2.1: After the condensation reaction, add ice water and adjust the pH of the reaction solution to 6-7 using a saturated sodium carbonate solution. S2.2: The reaction solution after step S2.1 is precipitated, filtered, dried and purified to obtain the second product as a yellow solid; S3: Take the product from step S2, add malononitrile to it, and the molar ratio of the product from step S2 to malononitrile is 1:(1.2-1.5). Add catalyst ③ and carry out a condensation reaction at 120-140℃ to obtain the product from step S3. S3.1: After the condensation reaction, add distilled water and stir for 0.5 h; S3.2: The reaction solution after step S3.1 is precipitated, filtered, dried and purified to obtain the third product as a red solid; S4: Take the product from the third step of S3, add p-dimethylaminobenzaldehyde and catalyst ④, and carry out a condensation reaction at 120-140℃ to obtain a faceted chiral [2.2]cycloaryl-4-(dicyanomethylene)-4H-pyran; S4.1: After the condensation reaction, extract with dichloromethane and remove the solvent by rotary evaporation; S4.2: The reaction solution after step S4.1 is precipitated, filtered, dried and purified to obtain a red solid chiral [2.2]cycloaryl-4-(dicyanomethylene)-4H-pyran.

3. The method for preparing chiral [2.2] cyclic aromatic compounds according to claim 2, characterized in that, In step S1, the condensation reaction is carried out in tetrahydrofuran solvent, the catalyst ① is a tetrahydrofuran suspension of sodium hydride, and the molar ratio of the catalyst ① to the chiral 5-acetyl-4-hydroxy[2.2]cycloaromatic compound is (4-5):

1.

4. The method for preparing chiral [2.2] cyclic aromatic compounds according to claim 3, characterized in that, In step S2, the condensation reaction is carried out in acetic acid as the solvent, the catalyst ② is acetic acid and concentrated sulfuric acid, and the molar ratio of the first step product to concentrated sulfuric acid is 1:(0.02-0.06).

5. The method for preparing chiral [2.2] cyclic aromatic compounds according to claim 4, characterized in that, In step S3, the condensation reaction is carried out in acetic anhydride as the solvent, and the catalyst ③ is acetic anhydride.

6. The method for preparing chiral [2.2]cyclic aromatic compounds according to claim 5, characterized in that, In step S4, the condensation reaction is carried out in toluene as a solvent, and the catalyst ④ is piperidine and acetic acid.

7. The application of the chiral [2.2] cyclic aromatic compound according to claim 1, characterized in that, Take 5×10 - 4 mol / L chiral [2.2] cycloaryl-4-(dicyanomethylene)-4H-pyran 36 μL, 5 × 10 -3 30 μL and 5 × 10 mol / L chiral cyclic aromatic pyranone compounds -4 540 μL of mol / L trifluoroacetic acid was added to 2384 μL of dichloromethane solution to obtain a white emission solution.

Images