A chiral compound based on cyclophane derivatives and its synthesis method and application

Abstract

The present invention proposes a chiral compound based on cyclophane derivatives, a synthesis method and application thereof. The chiral compound achieves intermolecular aggregation of organic light-emitting elements by fixing a luminescent group on a rigid molecular skeleton and regulating the molecular size of the rigid skeleton, thereby avoiding aggregation fluorescence quenching effect to a certain extent. At the same time, the chiral compound can also obtain a supramolecular assembly or a chiral aggregate through self-assembly of chiral molecules, thereby obtaining a chiral organic light-emitting material, which not only has a circularly polarized luminescence property, but also has a high fluorescence quantum yield. At the same time, the synthesis method of the present invention is simple and has a high product yield.

Description

Technical Field

[0001] The present invention relates to the technical field of chiral compounds, and in particular to a chiral compound based on cyclophane derivatives, a synthesis method and application thereof. Background Art

[0002] Organic light-emitting materials have very broad application prospects in the fields of light-emitting diodes, solar cells, field-effect transistors and stimulus-responsive materials. The performance of organic light-emitting materials depends not only on the structure of organic molecules, but also on the non-covalent bond forces and stacking patterns between molecules. Different from the luminescence properties of monomer molecules, the luminescence in the aggregated state has the characteristics of large stock shift, no fine structure and wide emission spectrum, which has potential application value in optoelectronic devices, chemical and biological sensors and cell imaging.

[0003] Chirality is a common phenomenon in nature. Chiral materials have some intrinsic special properties due to their broken structural symmetry: circular dichroism, linear polarization deflection, frequency doubling, piezoelectricity, pyroelectricity, ferroelectricity and topological quantum properties. Among them, circular dichroism means that chiral materials can selectively absorb or emit left-handed circularly polarized light and right-handed circularly polarized light, which is also a unique property of chiral materials. Chiral luminophores will produce left-handed polarized light and right-handed polarized light in the excited state. When the left-handed and right-handed polarized light are not equal, circularly polarized light will be generated. This kind of chiral material has broad application prospects in chemical sensing, biological probes, three-dimensional display, photocatalytic asymmetric synthesis and other fields, and has become a research hotspot in the field of chemical materials in recent years.

[0004] At present, chiral materials with luminescent properties (i.e., chiral organic luminescent materials) are of great significance to the further development of display technologies such as light-emitting diodes. Therefore, the synthesis and functional research of chiral organic luminescent materials have received much attention in recent years. One of the main problems faced by the research of chiral organic luminescent materials is that the synthesis methods of chiral organic luminescent materials are very limited. On the one hand, chiral organic luminescent materials with high optical purity are usually prepared by multi-step reactions using chiral source compounds as raw materials, which leads to low reaction efficiency and poor economy; on the other hand, although the effect of chiral proliferation can be maximized through asymmetric catalytic synthesis technology, the optical purity and fluorescence properties of the obtained target compounds are often not ideal. Therefore, it is extremely urgent to carry out catalytic synthesis and application research of chiral organic luminescent materials. Summary of the invention

[0005] Based on the technical problems existing in the background technology, the present invention proposes a chiral compound based on cyclophane derivatives, a synthesis method and application thereof, wherein the chiral compound fixes the luminescent group on a rigid molecular skeleton and achieves intermolecular aggregation of the organic luminescent unit by regulating the molecular size of the rigid skeleton, thereby avoiding the aggregation fluorescence quenching effect to a certain extent. At the same time, the chiral compound can also obtain a supramolecular assembly or a chiral aggregate through self-assembly of chiral molecules, thereby obtaining a chiral organic light-emitting material, which not only has a circularly polarized luminescence property, but also has a high fluorescence quantum yield; at the same time, the synthesis method described in the present invention is simple and the product yield is high.

[0006] The present invention provides a chiral compound based on a cyclophane derivative, which has the following structural formula:

[0007]

[0008] Wherein, n is 0 or a positive integer.

[0009] Preferably, n is 0 or 3.

[0010] Preferably, the chiral compound is any one of the compounds represented by the following structural formulas:

[0011]

[0012] The present invention also proposes a method for synthesizing the chiral compound based on the cyclophane derivative, and the synthesis route thereof is as follows:

[0013]

[0014]

[0015] Preferably, the compound represented by structural formula 2 is obtained by subjecting the compound represented by structural formula 1 to an acylation reaction with 1,1-dichloromethyl ether under the catalytic condition of titanium tetrachloride;

[0016] The racemic compound represented by the structural formula (rac)-3 is obtained by subjecting the compound represented by the structural formula 2 to aldimination reaction with (R)-phenylethylamine.

[0017] Preferably, the compound represented by structural formula (S)-4 or (R)-4 is obtained by recrystallizing the racemic compound represented by structural formula (rac)-3 at least twice to obtain the compound represented by structural formula (Sp, R)-3 or (Rp, R)-3; the compound represented by structural formula (Sp, R)-3 or (Rp, R)-3 is hydrolyzed and separated to obtain the compound represented by structural formula (S)-2 or (R)-2, and then reduced to phenol under hydrogen peroxide / sulfuric acid conditions to obtain the compound represented by structural formula (S)-4 or (R)-4.

[0018] Preferably, the compound represented by structural formula (S)-5 or (R)-5 is obtained by esterifying the compound represented by structural formula (S)-4 or (R)-4 with 1-pyrenecarboxylic acid.

[0019] Preferably, the compound represented by structural formula (S)-6 or (R)-6 is obtained by esterifying the compound represented by structural formula (S)-4 or (R)-4 with 1-pyrenebutyric acid.

[0020] The present invention also provides a chiral organic light-emitting material, which is the chiral compound based on the cyclophane derivative.

[0021] Compared with the prior art, the present invention has the following technical effects:

[0022] The method achieves intermolecular aggregation of organic light-emitting elements by fixing the light-emitting group on a rigid molecular skeleton and regulating the molecular size of the rigid skeleton, thereby avoiding the aggregation fluorescence quenching effect to a certain extent. At the same time, the chiral compound can also obtain a supramolecular assembly or a chiral aggregate through self-assembly of chiral molecules, thereby obtaining a chiral organic light-emitting material, which not only has a circularly polarized luminescence property, but also has a high fluorescence quantum yield. At the same time, the synthesis method of the present invention is simple and has a high product yield. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The H NMR spectrum of the compound represented by the structural formula (R) / (S)-5 1 HNMR spectra;

[0024] Figure 2 The NMR carbon spectrum of the compound represented by the structural formula (R) / (S)-5 13 CNMR images;

[0025] Figure 3 The H NMR spectrum of the compound represented by the structural formula (R) / (S)-6 1 HNMR spectra;

[0026] Figure 4 The NMR carbon spectrum of the compound represented by the structural formula (R) / (S)-6 13 CNMR images;

[0027] Figure 5 is the fluorescence emission spectrum of the compound represented by structural formula (S)-5 / 6;

[0028] Figure 6 Circular dichroism spectra of the compounds represented by structural formulas (R) / (S)-5 and (R) / (S)-6. DETAILED DESCRIPTION

[0029] The technical solutions of the present invention are described in detail below through specific embodiments. However, it should be clearly stated that these embodiments are for illustration only and are not to be construed as limiting the scope of the present invention.

[0030] Example 1

[0031] A chiral compound based on a cyclophane derivative, the structural formula of which is shown below:

[0032]

[0033] The chiral compound is prepared by the following synthesis method:

[0034] (1) Preparation of the racemic compound represented by structural formula (rac)-3

[0035] At 0°C, titanium tetrachloride (6.6 mL, 60.0 mmol) and 1,1-dichloromethyl ether (3.0 mL, 33.0 mmol) were added to a stirred solution of [2,2](1,4)cyclophane (the compound shown in formula 1, 6.24 g, 30.0 mmol) in dichloromethane (150 mL). The mixture was stirred at room temperature for 6 h and then poured into water (150 mL). The mixture was stirred for another 3 h. After the two phases of the reaction solution were separated, the aqueous phase was extracted with dichloromethane (100 mL) and the organic phases were combined. The mixture was dried with anhydrous sodium sulfate, filtered, and the solvent was removed under reduced pressure to obtain a white solid, i.e., the compound shown in formula 2 (6.78 g, yield 95.6%).

[0036] The compound represented by structural formula 2 (5.4 g, 22.85 mmol) and (R)-phenylethylamine (2.9 g, 24.0 mmol) were added to toluene (80 mL), and the mixture was heated under reflux at 110° C. for 16 h. After the reaction, the solvent was removed under reduced pressure to obtain a racemic compound represented by structural formula (rac)-3 (7.6 g, yield 98.0%);

[0037] (2) Preparation of the compound represented by structural formula (S)-4

[0038] The racemic compound (7.6 g, 22.4 mmol) of structural formula (rac)-3 was added to n-hexane (75 mL) for the first recrystallization to obtain flaky crystals, i.e., the compound of structural formula (Sp, R)-3. The filtrate obtained after the first recrystallization was dried and added to n-hexane (20 mL) for the second recrystallization to obtain needle-shaped crystals, i.e., the compound of structural formula (Rp, R)-3. The filtrate obtained after the second recrystallization was dried and added to n-hexane (45 mL) for the third recrystallization to obtain flaky crystals, i.e., The compound is represented by the structural formula (Sp, R)-3. The filtrate obtained by the third recrystallization is then dried and added to n-hexane (15 mL) for the fourth recrystallization, and needle-shaped crystals are also obtained, which is the compound represented by the structural formula (Rp, R)-3; the flake crystals obtained twice are combined to obtain the compound represented by the structural formula (Sp, R)-3 (1.53 g, 4.50 mmol, yield 20.0%), and the needle-shaped crystals obtained twice are combined to obtain the compound represented by the structural formula (Rp, R)-3 (1.48 g, 4.35 mmol, yield 19.1%);

[0039] The compound represented by the structural formula (Sp, R)-3 (1.35 g, 3.98 mmol) was hydrolyzed and separated on a silica gel column using dichloromethane as the eluent to obtain a white solid, namely the compound represented by the structural formula (S)-2 (925 mg, 3.91 mmol, 98.2%);

[0040] To a mixed solution (100 mL) of dichloromethane / methanol (volume ratio 1:1) containing the compound of structural formula (S)-2 (847 mg, 3.58 mmol) was added 98% concentrated sulfuric acid (15 drops) and 50% hydrogen peroxide (hydrogen peroxide, 0.2 mL), and the mixture was stirred at room temperature for 24 h, and the solvent was removed under reduced pressure. The residue was added with dichloromethane (50 mL) and dissolved completely, and then washed with water (50 mL). The aqueous phase was extracted with dichloromethane (50 mL) and the organic phases were combined, and then dried with anhydrous sodium sulfate, filtered, and the solvent was removed under reduced pressure. The crude product was purified by silica gel column chromatography using petroleum ether: ethyl acetate = 9:1 as the eluent to obtain a light yellow solid, which is the compound of structural formula (S)-4 (642 g, 2.86 mmol, yield 80.0%);

[0041] (3) Preparation of the compound represented by structural formula (S)-5

[0042] The compound represented by the structural formula (S)-4 (110 mg, 0.49 mmol), 1-pyrenecarboxylic acid (150 mg, 0.59 mmol), 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide (EDC, 500 mg, 3.2 mmol) and 4-dimethylaminopyridine (DMAP, 100 mg, 0.82 mmol) were added to dichloromethane (25 mL), and the reaction was stirred at room temperature for 24 hours. The reaction progress was monitored by TLC. When the reaction was complete, the aqueous phase was extracted with dichloromethane (3×25 mL), and the organic phase was washed with saturated brine, dried with anhydrous magnesium sulfate, filtered, and evaporated to remove the solvent. The compound represented by the structural formula (S)-5 (120 mg, TLR 400) was obtained after purification by silica gel column chromatography using petroleum ether: dichloromethane = 2:1 as the eluent. f =0.3, yield 53.9%), the H NMR spectrum and C NMR spectrum of the compound represented by the structural formula (S)-5 are as follows Figure 1 , 2 shown.

[0043] Example 2

[0044] A chiral compound based on a cyclophane derivative, the structural formula of which is shown below:

[0045]

[0046] The chiral compound is prepared by the following synthesis method:

[0047] (1) Preparation of the compound represented by structural formula (R)-4

[0048] The compound represented by the structural formula (Rp, R)-3 (1.35 g, 3.98 mmol) was hydrolyzed and separated on a silica gel column using dichloromethane as the eluent to obtain a white solid, namely the compound represented by the structural formula (R)-2 (920 mg, 3.89 mmol, 97.5%);

[0049] To a mixed solution (100 mL) of dichloromethane / methanol (volume ratio 1:1) containing the compound represented by the structural formula (R)-2 (847 mg, 3.58 mmol) was added 98% concentrated sulfuric acid (15 drops) and 50% hydrogen peroxide (hydrogen peroxide, 0.2 mL), and the mixture was stirred at room temperature for 24 h, and the solvent was removed under reduced pressure. The residue was added with dichloromethane (50 mL) and dissolved completely, and then washed with water (50 mL). The aqueous phase was extracted with dichloromethane (50 mL) and the organic phases were combined, and then dried with anhydrous sodium sulfate, filtered, and the solvent was removed under reduced pressure. The crude product was purified by silica gel column chromatography using petroleum ether: ethyl acetate = 9:1 as the eluent to obtain a light yellow solid, which was the compound represented by the structural formula (R)-4 (638 mg, 2.84 mmol, yield 79.5%);

[0050] (2) Preparation of the compound represented by structural formula (R)-5

[0051] The compound represented by the structural formula (R)-4 (110 mg, 0.49 mmol), 1-pyrenecarboxylic acid (150 mg, 0.59 mmol), 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide (EDC, 500 mg, 3.2 mmol) and 4-dimethylaminopyridine (DMAP, 100 mg, 0.82 mmol) were added to dichloromethane (25 mL), and the reaction was stirred at room temperature for 24 hours. The reaction progress was monitored by TLC. When the reaction was complete, the aqueous phase was extracted with dichloromethane (3×25 mL), and the organic phase was washed with saturated brine, dried with anhydrous magnesium sulfate, filtered, and evaporated to remove the solvent. The compound represented by the structural formula (R)-5 (125 mg, TLR 400) was obtained after purification by silica gel column chromatography using petroleum ether: dichloromethane = 2:1 as the eluent. f =0.3, yield 56.0%), since the compound represented by structural formula (R)-5 and the compound represented by structural formula (S)-5 are chiral counterparts, the nuclear magnetic resonance hydrogen spectrum and carbon spectrum of the two are the same, that is, the nuclear magnetic resonance hydrogen spectrum and carbon spectrum of the compound represented by structural formula (R)-5 are also as follows Figure 1 , 2 shown.

[0052] Example 3

[0053] A chiral compound based on a cyclophane derivative, the structural formula of which is shown below:

[0054]

[0055] The chiral compound is prepared by the following synthesis method:

[0056] (1) Preparation of the compound represented by structural formula (S)-6

[0057] The compound represented by the structural formula (S)-4 (110 mg, 0.49 mmol), 1-pyrenebutyric acid (170 mg, 0.59 mmol), 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide (EDC, 500 mg, 3.2 mmol) and 4-dimethylaminopyridine (DMAP, 100 mg, 0.82 mmol) were added to dichloromethane (25 mL), and the reaction was stirred at room temperature for 24 hours. The reaction progress was monitored by TLC. When the reaction was complete, the aqueous phase was extracted with dichloromethane (3×25 mL), and the organic phase was washed with saturated brine, dried with anhydrous magnesium sulfate, filtered, and evaporated to remove the solvent. The compound represented by the structural formula (S)-6 (133 mg, TLR 400) was obtained after purification by silica gel column chromatography using petroleum ether: dichloromethane = 2:1 as the eluent. f=0.3, yield 55.0%), the H NMR spectrum and C NMR spectrum of the compound represented by the structural formula (S)-6 are as follows Figure 3 , 4 shown.

[0058] Example 4

[0059] A chiral compound based on a cyclophane derivative, the structural formula of which is shown below:

[0060]

[0061] The chiral compound is prepared by the following synthesis method:

[0062] (1) Preparation of the compound represented by structural formula (R)-6

[0063] The compound represented by the structural formula (R)-4 (110 mg, 0.49 mmol), 1-pyrenebutyric acid (170 mg, 0.59 mmol), 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide (EDC, 500 mg, 3.2 mmol) and 4-dimethylaminopyridine (DMAP, 100 mg, 0.82 mmol) were added to dichloromethane (25 mL), and the reaction was stirred at room temperature for 24 hours. The reaction progress was monitored by TLC. When the reaction was complete, the aqueous phase was extracted with dichloromethane (3×25 mL), and the organic phase was washed with saturated brine, dried with anhydrous magnesium sulfate, filtered, and evaporated to remove the solvent. The compound represented by the structural formula (R)-6 (126 mg, TLR 400) was obtained after purification by silica gel column chromatography using petroleum ether: dichloromethane = 2:1 as the eluent. f =0.3, yield 52%), since the compound represented by structural formula (R)-6 and the compound represented by structural formula (S)-6 are chiral counterparts, the nuclear magnetic resonance hydrogen spectrum and carbon spectrum of the two are the same, and the nuclear magnetic resonance hydrogen spectrum and carbon spectrum of the compound represented by structural formula (R)-6 are also as follows Figure 3 , 4 shown.

[0064] The compound represented by (S)-5 / 6 (i.e., the structural formula (S)-5 or (S)-6) was dissolved in chloroform. -5 M) was tested for steady-state fluorescence spectroscopy (PL), and the results are shown in Figure 5 As shown; Figure 5 is the fluorescence emission spectrum of the compound represented by structural formula (S)-5 / 6; Figure 5It can be seen that the compound represented by structural formula (S)-5 has a monomer emission band in the 390-450nm region, and under 365nm light excitation, the spectrum of the compound represented by structural formula (S)-5 shows that the monomer fluorescence emission peak appears at 400nm and 420nm; the compound represented by structural formula (S)-6 has a monomer emission band in the 380-430nm region and a weak shoulder peak at 425nm. Under 365nm light excitation, the spectrum of the compound represented by structural formula (S)-6 shows that the monomer fluorescence emission peak appears at 380nm and 399nm; that is, at a concentration of 0.05mM, the PL quantum yield (Φ PL ) is 0.05, the PL quantum yield (Φ PL ) is 0.06.

[0065] The circular dichroism (CD) spectra of the compounds represented by the structural formula (R) / (S)-5 and (R) / (S)-6 were tested, and the CD spectra of the compounds in chloroform solution (c = 5×10 -5 M) in the ground state chirality, the result is Figure 6 As shown; Figure 6 is the circular dichroism spectrum of the compounds represented by the structural formula (R) / (S)-5 and (R) / (S)-6; Figure 6 It can be seen that the compounds represented by the structural formulas (R) / (S)-5 and (R) / (S)-6 show an obvious mirror-image cotton effect at 250nm-300nm, from which it can be judged that these signals located at 270nm can be regarded as the molecular chirality of the chiral cyclophane skeleton, confirming that the present invention successfully achieves the chiral separation of cyclophane molecules by chemical methods.

[0066] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A chiral compound based on a cyclophane derivative, characterized in that: It has the following structural formula: Where n is 0 or 3.

2. The chiral compound based on cyclophane derivatives according to claim 1, characterized in that: It is any one of the compounds shown in the following structural formulas:

3. A method for synthesizing a chiral compound based on a cyclophane derivative according to claim 2, characterized in that: Its synthetic route is as follows:

4. The method for synthesizing a chiral compound based on a cyclophane derivative according to claim 3, characterized in that: The compound represented by structural formula 2 is obtained by subjecting the compound represented by structural formula 1 to an acylation reaction with 1,1-dichloromethyl ether under the catalytic condition of titanium tetrachloride; The racemic compound represented by the structural formula (rac)-3 is obtained by subjecting the compound represented by the structural formula 2 to aldimination reaction with (R)-phenylethylamine.

5. The method for synthesizing a chiral compound based on a cyclophane derivative according to claim 3 or 4, characterized in that: The compound represented by structural formula (S)-4 or (R)-4 is obtained by subjecting the racemic compound represented by structural formula (rac)-3 to recrystallization at least twice to obtain the compound represented by structural formula (Sp, R)-3 or (Rp, R)-3; the compound represented by structural formula (Sp, R)-3 or (Rp, R)-3 is subjected to hydrolysis and separation reaction to obtain the compound represented by structural formula (S)-2 or (R)-2, and then reduced to phenol under hydrogen peroxide / sulfuric acid conditions to obtain the compound represented by structural formula (S)-4 or (R)-4.

6. The method for synthesizing a chiral compound based on a cyclophane derivative according to claim 3 or 4, characterized in that: The compound represented by the structural formula (S)-5 or (R)-5 is obtained by subjecting the compound represented by the structural formula (S)-4 or (R)-4 to esterification reaction with 1-pyrenecarboxylic acid.

7. The method for synthesizing a chiral compound based on a cyclophane derivative according to claim 3 or 4, characterized in that: The compound represented by the structural formula (S)-6 or (R)-6 is obtained by esterifying the compound represented by the structural formula (S)-4 or (R)-4 with 1-pyrenebutyric acid.

8. A chiral organic light-emitting material, characterized in that: It is a chiral compound based on a cyclophane derivative as claimed in claim 1 or 2.

Images