Chiral rare earth supramolecular spirochete complex as well as preparation method and application thereof

Abstract

The invention relates to a chiral rare earth supramolecular spirochete complex as well as a preparation method and application thereof, in particular to a chiral rare earth supramolecular spirochete complex as well as a preparation method and application thereof. The invention aims to solve the problems that the existing luminescent rare earth-based supramolecular material for chiral amine sensing is complicated in treatment process, relatively weak in material stability and difficult to be converted into a device. According to the chiral rare earth supramolecular spiral luminescent probe disclosed by the invention, due to a secondary spiral structure generated by ligand chirality, the chiral rare earth supramolecular spiral luminescent probe has specific recognition capability of chiral amine in space, and two enantiomers of the chiral amine can be accurately distinguished by detecting the change of a glm value; moreover, the chiral rare earth supramolecular spiral body can be dissolved in various organic solvents and can be converted into devices more easily, so that the preparation process is simplified, the synthesis cost is low, and the possibility of large-scale industrial application is achieved.

Description

Technical Field

[0001] The present invention belongs to the field of chiral supramolecular sensing, and particularly relates to a chiral rare earth supramolecular helical complex, a preparation method thereof, and an application thereof. Background Art

[0002] Chiral amines are present in many bioactive substances and are important chiral auxiliaries as well as key synthetic intermediates for pharmaceuticals and natural products. However, the metabolic processes, pharmacological activities, and toxicities of the two enantiomers of chiral chemical drugs in the human body often show significant differences. Usually, only one of a pair of enantiomers of chiral chemical drugs has clinical application value. Therefore, the ability to accurately distinguish a pair of chiral amine enantiomers will be of great significance in the synthesis and production of chiral drugs and chiral intermediates.

[0003] Most of the reported luminescent rare earth supramolecules for sensing chiral amines are rare earth metal-organic frameworks (Ln-MOFs) materials. Although Ln-MOFs with appropriate internal pore sizes and structures can achieve the sensing of chiral amines, during the synthesis process of the MOF framework, solvent molecules are extremely likely to bind to unsaturated rare earth Ln centers or be encapsulated in the Ln-MOFs pores. The presence of these solvent molecules not only hinders the entry of chiral amine molecules, but also the methods for removing these coordinated and encapsulated solvent molecules are mostly limited to traditional pyrolysis strategies. Such high-temperature reactions are not only complex in process, poor in controllability, but also extremely sensitive to the gas environment, easily causing phenomena such as framework collapse, metal center aggregation, and pore structure blockage, and the stability of the material is weak. At the same time, the pyrolysis process will inevitably lead to the decomposition of expensive organic ligands in the MOFs and the emission of toxic and harmful gases, increasing the economic and environmental costs of the synthesis process. In addition, due to the extremely low solubility of metal-organic framework (MOFs) materials in most organic solvents, it is necessary to go through cumbersome preparation processes to device them and apply them. Therefore, it limits the possibility of large-scale industrial application of metal-organic frameworks. Summary of the Invention

[0004] In order to solve the problems of the complex processing process, weak material stability, and difficulty in deviceization of the existing luminescent rare earth-based supramolecular materials for chiral amine sensing, the present invention proposes a preparation method and an application of a chiral rare earth supramolecular helical complex.

[0005] The structural formula of the chiral rare earth supramolecular helical complex of the present invention is:

[0006]

[0007] The general structural formula of the chiral rare earth supramolecular helical complex is Ln2L4, which is a chiral rare earth complex composed of the chiral ligand L and rare earth elements; the structural formula of the chiral ligand L is:

[0008]

[0009] The preparation method of the above chiral rare earth supramolecular helical complex is carried out according to the following steps:

[0010] Step 1: Synthesis of S-(+)-2,2'-dimethoxy-1,1'-binaphthalene:

[0011] Weigh 2 - 3 g of the mixture of sodium hydride and kerosene and dissolve it in a mixed solvent of 100 - 150 mL of tetrahydrofuran and 60 - 100 mL of N,N-dimethylformamide to obtain a sodium hydride solution;

[0012] Weigh 5 - 8 g of S-binaphthol and dissolve it in 20 - 50 mL of tetrahydrofuran solvent, then drop it into the sodium hydride solution under an ice-water bath. When no gas escapes after stirring, add 7 - 10 g of methyl iodide dropwise to the reaction solution and continuously stir at room temperature for 24 hours; after the reaction is complete, pour the reaction solution into 200 - 250 mL of water to quench it, and filter to obtain the crude product S-(+)-2,2'-dimethoxy-1,1'-binaphthalene; the crude product is recrystallized and purified in acetonitrile solvent to obtain S-(+)-2,2'-dimethoxy-1,1'-binaphthalene;

[0013] Step 2: Synthesis of S-(+)-2,2'-dimethoxy-1,1'-binaphthalene-3,3'-diboronic acid:

[0014] Under nitrogen protection, dissolve 7 - 10 mL of tetramethylethylenediamine and 18 - 20 mL of n-butyllithium in 100 - 150 mL of anhydrous ether, and continuously stir at room temperature for 30 minutes. Then add 5 - 8 g of S-(+)-2,2'-dimethoxy-1,1'-binaphthalene and continue to stir at room temperature for 3 h to obtain a light brown suspension; cool the suspension to -78 °C, and then drop 18 - 20 mL of triethyl borate into the suspension. After the dropping is complete, restore the reaction solution to room temperature and continue to stir for 12 hours; after the reaction ends, pour the reaction solution into a 5% NaOH aqueous solution and stir until it is completely clear; then perform reverse extraction with dichloromethane, collect the aqueous layer, adjust the pH of the aqueous layer to 2 - 3 with dilute hydrochloric acid, filter the precipitated white precipitate and wash it with 30 - 50 mL of water, and dry to obtain S-(+)-2,2'-dimethoxy-1,1'-binaphthalene-3,3'-diboronic acid;

[0015] Step 3: Synthesis of S-(+)-2,2'-dimethoxy-3,3'-bis(4,4',4''-trifluoro-1,3-dioxobutyl)phenyl-1,1'-binaphthalene:

[0016] Under nitrogen protection, weigh 8 - 10 g of S-(+)-2,2'-dimethoxy-1,1'-binaphthalene-3,3'-diboronic acid, 8 - 10 g of 3-bromoacetophenone, and 2 - 5 g of Pd(PPh3)4, dissolve them in 100 - 150 mL of tetrahydrofuran, and heat to reflux. After refluxing, add 50 - 60 mL of aqueous Na2CO3 solution and continue the reaction for 24 hours. After the reaction is completed, cool the reaction mixture to room temperature and extract with ethyl acetate. Collect the organic layer, dry, filter, and then distill off ethyl acetate under reduced pressure to obtain the crude product. The crude product is recrystallized from a mixed solution of absolute ethanol and dichloromethane to obtain S-(+)-2,2'-dimethoxy-3,3'-bis(4,4',4”-trifluoro-1,3-dioxobutyl)phenyl-1,1'-binaphthalene;

[0017] Step 4: Synthesis of ligand L:

[0018] Weigh 0.7 - 0.9 g of sodium methoxide and 3 - 5 g of ethyl heptafluorobutyrate, dissolve them in 30 - 50 mL of dimethyl ether, then add 1 - 2 g of S-(+)-2,2'-dimethoxy-3,3'-bis(4,4',4”-trifluoro-1,3-dioxobutyl)phenyl-1,1'-binaphthalene, and react at room temperature for 24 hours. After the reaction is complete, pour the reaction solution into water and adjust the pH of the solution to 2 - 3 with hydrochloric acid to precipitate a solid. Filter to obtain the crude product, and wash and dry the obtained crude product to obtain ligand L;

[0019] Step 5: Preparation of chiral rare earth supramolecular helical complex Ln2L4:

[0020] Weigh 0.2 - 0.5 g of ligand L and 0.1 - 0.3 g of aqueous tetramethylammonium hydroxide, dissolve them in 10 - 20 mL of acetonitrile, and stir until the solution is clear. Dropwise add an acetonitrile solution of 0.06 - 0.07 g of Eu(OTf)3 to the reaction solution and stir at room temperature for 24 hours. After the reaction is complete, pour the reaction solution into water to precipitate a solid, and filter to obtain the chiral rare earth supramolecular helical complex Ln2L4.

[0021] The above chiral rare earth supramolecular helical complex is used for the detection of chiral amines, and the detection method is carried out according to the following steps:

[0022] I. Mix the chiral rare earth supramolecular helical complex with a test solvent to obtain a chiral rare earth supramolecular helical complex solution; under the excitation of light at 375 nm, measure the luminescence dissymmetry factor spectral signal value (g lum ) of the chiral rare earth supramolecular helical complex solution;

[0023] II. Mix the analyte solution with the chiral rare-earth supramolecular helical complex solution obtained in Step I to obtain a mixed solution, and measure the luminescence dissymmetry factor spectral signal value (g lum ) of the mixed solution under the excitation of light at 375 nm;

[0024] The analyte in the analyte solution is (R,R)-cyclohexanediamine or (S,S)-cyclohexanediamine;

[0025] The molar ratio of the analyte to the chiral rare-earth supramolecular helix is (0.01 - 10):1;

[0026] III. Compare the luminescence dissymmetry factor spectral signal value of the mixed solution obtained in Step II with the luminescence dissymmetry factor spectrum of the chiral rare-earth supramolecular helical complex solution obtained in Step I, and qualitatively analyze the enantiomers of the chiral amine and detect the enantiomeric composition through the change in the luminescence dissymmetry factor spectral signal value (g lum ).

[0027] The principle and beneficial effects of the present invention are as follows:

[0028] 1. The chiral rare-earth supramolecular helical complex of the present invention can accurately distinguish the enantiomers of chiral amines; the secondary helical structure of the chiral rare-earth supramolecular luminescence probe due to the chirality of the ligand endows it with specific recognition ability for chiral amines in space; at the same time, the coordination unit of the chiral ligand can have a weak reaction with the chiral amine, combined with the cooperative specific recognition of the chiral amine by the chiral ligand and the helical structure of the chiral rare-earth supramolecule, which changes the dissymmetry factor spectral signal (g lum value) of the chiral rare-earth supramolecule; therefore, the distinction of chiral amine enantiomers can be achieved by detecting the change in the g lum value.

[0029] 2. The chiral rare-earth supramolecule of the present invention has a helical structure with four ligands, and the eight oxygen atoms on the four β-diketone coordination units form a relatively compact and stable eight-coordination environment with the rare-earth ions, which effectively improves its stability as a sensor in practical applications; at the same time, the chiral rare-earth supramolecular helix of the present invention shows good solubility in a variety of organic solvents (such as tetrahydrofuran, acetonitrile, methanol, ethanol, etc.), making it easier to be deviceized in practical applications, thereby simplifying the traditional complex preparation process.

[0030] 3. The chiral rare-earth supramolecular helix of the present invention benefits from the unique axial chirality of the basic raw material binaphthol. As a chiral unit with both rigidity and flexibility, chiral binaphthol endows the chiral rare-earth supramolecular helix with strong structural rigidity, which is conducive to improving its stability in solution. However, when the chiral rare-earth supramolecular helix interacts with chiral amines, the chiral amine molecules are very likely to perturb the dihedral angle of the chiral binaphthol unit. Moreover, the spectral signal of the dissymmetry factor (g lum value) on the chiral rare-earth supramolecular helix of the present invention is extremely sensitive to the change of the dihedral angle of the chiral binaphthol unit. Therefore, the sensitivity and accuracy of the chiral rare-earth supramolecular helix of the present invention in spectral detection are greatly improved.

[0031] 4. The chiral rare-earth supramolecular helix of the present invention senses chiral amines through the open space on the periphery of the helix, enhancing the contact probability between the chiral amine molecules to be detected and the chiral rare-earth supramolecular helix, and further effectively improving the sensitivity and accuracy of the chiral rare-earth supramolecular helix in sensing chiral amines. Moreover, the synthesis method of the chiral rare-earth supramolecular helix of the present invention is relatively simple and the synthesis cost is low, making large-scale industrial application possible. Detailed Embodiments

[0032] The technical solution of the present invention is not limited to the following specific embodiments listed, but also includes any reasonable combination between specific embodiments.

[0033] Detailed Embodiment 1: The structural formula of the chiral rare-earth supramolecular helix complex in this embodiment is:

[0034]

[0035] The general structural formula of the chiral rare-earth supramolecular helix complex is Ln2L4, which is a chiral rare-earth complex composed of a chiral ligand L and a rare-earth element. The structural formula of the chiral ligand L is:

[0036]

[0037] This embodiment has the following beneficial effects:

[0038] 1. The chiral rare-earth supramolecular helix complex in this embodiment can accurately distinguish the enantiomers of chiral amines. The secondary helical structure generated by the chiral rare-earth supramolecular helix luminescent probe due to the chirality of the ligand endows it with specific recognition ability for chiral amines in space. At the same time, the coordination unit of the chiral ligand can have a weak reaction with chiral amines. Combining the cooperative specific recognition of chiral amines by the chiral ligand and the helical structure of the chiral rare-earth supramolecule, the spectral signal of the dissymmetry factor (g lum value) of the chiral rare-earth supramolecular helix changes. Therefore, by detecting glum The discrimination of chiral amine enantiomers can be achieved by the change of the value.

[0039] 2. The chiral rare-earth supramolecule of this embodiment has a helical structure with four-strand ligands. Among them, the eight oxygen atoms on the four β-diketone coordination units form a relatively compact and stable eight-coordination environment with the rare-earth ions, which effectively improves its stability as a sensor in practical applications. At the same time, the chiral rare-earth supramolecular helix of this embodiment shows good solubility in a variety of organic solvents (such as tetrahydrofuran, acetonitrile, methanol, ethanol, etc.), making it easier to be device-ized in practical applications, thereby simplifying the traditional complex preparation process.

[0040] 3. The chiral rare-earth supramolecular helix of this embodiment benefits from the unique axial chirality of the basic raw material binaphthol. As a chiral unit with both rigidity and flexibility, chiral binaphthol endows the chiral rare-earth supramolecular helix with strong structural rigidity, which is conducive to improving its stability in solution. However, when the chiral rare-earth supramolecular helix interacts with chiral amine, the chiral amine molecule is very likely to disturb the dihedral angle of the chiral binaphthol unit, and the spectroscopic signal of the asymmetry factor (g lum value) on the chiral rare-earth supramolecular helix of this embodiment is extremely sensitive to the change of the dihedral angle of the chiral binaphthol unit. Therefore, the sensitivity and accuracy of the chiral rare-earth supramolecular helix of this embodiment in spectroscopic detection are greatly improved.

[0041] 4. The chiral rare-earth supramolecular helix of this embodiment senses chiral amine through the open space on the periphery of the helix, enhancing the contact probability between the chiral amine molecules to be detected and the chiral rare-earth supramolecular helix, and further effectively improving the sensitivity and accuracy of the chiral rare-earth supramolecular helix in sensing chiral amine. Moreover, the synthesis method of the chiral rare-earth supramolecular helix of this embodiment is relatively simple and the synthesis cost is low, making it possible for large-scale industrial application.

[0042] Specific Embodiment 2: The preparation method of the chiral rare-earth supramolecular helix complex of this embodiment is carried out according to the following steps:

[0043] Step 1: Synthesis of S-(+)-2,2'-dimethyl ether-1,1'-binaphthyl:

[0044] Weigh 2 - 3 g of the mixture of sodium hydride and kerosene and dissolve it in a mixed solvent of 100 - 150 mL of tetrahydrofuran and 60 - 100 mL of N,N-dimethylformamide to obtain a sodium hydride solution;

[0045] Weigh 5 - 8 g of S - binaphthol and dissolve it in 20 - 50 mL of tetrahydrofuran solvent. Then, drop it into the sodium hydride solution under an ice - water bath. When no gas escapes after stirring, add 7 - 10 g of methyl iodide dropwise to the reaction solution and continuously stir at room temperature for 24 hours. After the reaction is complete, pour the reaction solution into 200 - 250 mL of water to quench it, and filter to obtain the crude product S-(+)-2,2'-dimethyl ether - 1,1'-binaphthyl. The crude product is recrystallized and purified in acetonitrile solvent to obtain S-(+)-2,2'-dimethyl ether - 1,1'-binaphthyl.

[0046] Step 2: Synthesis of S-(+)-2,2'-dimethoxy - 1,1'-binaphthyl - 3,3'-diboronic acid:

[0047] Under nitrogen protection, dissolve 7 - 10 mL of tetramethylethylenediamine and 18 - 20 mL of n - butyllithium in 100 - 150 mL of anhydrous ether, and continuously stir at room temperature for 30 minutes. Then add 5 - 8 g of S-(+)-2,2'-dimethyl ether - 1,1'-binaphthyl and continue to stir at room temperature for 3 h to obtain a light - brown suspension. Cool the suspension to - 78 °C, and then drop 18 - 20 mL of triethyl borate into the suspension. After the dropping is complete, restore the reaction solution to room temperature and continue to stir for 12 hours. After the reaction ends, pour the reaction solution into a 5% NaOH aqueous solution and stir until it is completely clear. Then perform reverse extraction with dichloromethane, collect the aqueous layer, adjust the pH of the aqueous layer to 2 - 3 with dilute hydrochloric acid, filter the precipitated white solid, wash it with 30 - 50 mL of water, and dry to obtain S-(+)-2,2'-dimethoxy - 1,1'-binaphthyl - 3,3'-diboronic acid.

[0048] Step 3: Synthesis of S-(+)-2,2'-dimethoxy - 3,3'-bis(4,4',4”-trifluoro - 1,3 - dioxobutyl)phenyl - 1,1'-binaphthyl:

[0049] Under nitrogen protection, weigh 8 - 10 g of S-(+)-2,2'-dimethoxy - 1,1'-binaphthyl - 3,3'-diboronic acid, 8 - 10 g of 3 - bromoacetophenone, and 2 - 5 g of Pd(PPh3)4, dissolve them in 100 - 150 mL of tetrahydrofuran, and heat to reflux. After refluxing, add 50 - 60 mL of Na2CO3 aqueous solution and continue the reaction for 24 hours. After the reaction is completed, cool the reaction mixture to room temperature and extract with ethyl acetate. Collect the organic layer, dry and filter it, and then distill off ethyl acetate under reduced pressure to obtain the crude product. The crude product is recrystallized in a mixed solution of anhydrous ethanol and dichloromethane to obtain S-(+)-2,2'-dimethoxy - 3,3'-bis(4,4',4”-trifluoro - 1,3 - dioxobutyl)phenyl - 1,1'-binaphthyl.

[0050] Step 4: Synthesis of ligand L:

[0051] Weigh 0.7 - 0.9 g of sodium methoxide and 3 - 5 g of ethyl heptafluorobutyrate and dissolve them in 30 - 50 mL of dimethyl ether. Then add 1 - 2 g of S-(+)-2,2'-dimethoxy-3,3'-bis(4,4',4''-trifluoro-1,3-dioxobutyl)phenyl-1,1'-binaphthalene and react at room temperature for 24 hours. After the reaction is complete, pour the reaction solution into water and adjust the pH of the solution to 2 - 3 with hydrochloric acid to precipitate a solid. Filter to obtain the crude product. After washing the obtained crude product with water and drying, the ligand L is obtained.

[0052] Step Five: Prepare the chiral rare earth supramolecular helical complex Ln2L4:

[0053] Weigh 0.2 - 0.5 g of ligand L and 0.1 - 0.3 g of aqueous tetramethylammonium hydroxide and dissolve them in 10 - 20 mL of acetonitrile. Stir until the solution is clear. Dropwise add the acetonitrile solution of 0.06 - 0.07 g of Eu(OTf)3 to the reaction solution and stir at room temperature for 24 hours. After the reaction is complete, pour the reaction solution into water to precipitate a solid. Filter to obtain the chiral rare earth supramolecular helical complex Ln2L4.

[0054] 1. The chiral rare earth supramolecular helical complex of this embodiment can accurately distinguish the enantiomers of chiral amines. The secondary helical structure generated by the chiral rare earth supramolecular luminescent probe due to the chirality of the ligand endows it with the specific recognition ability for chiral amines in space. At the same time, the coordination unit of the chiral ligand can undergo a weak reaction with chiral amines. Combining the cooperative specific recognition of chiral amines by the chiral ligand and the helical structure of the chiral rare earth supramolecule causes the change of the spectral signal of the dissymmetry factor (g lum value) of the chiral rare earth supramolecule. Therefore, by detecting the change of the g lum value, the discrimination of the enantiomers of chiral amines can be achieved.

[0055] 2. The chiral rare earth supramolecule of this embodiment has a helical structure with four ligands. The eight oxygen atoms on the four β-diketone coordination units form a relatively compact and stable eight-coordination environment with rare earth ions, which effectively improves its stability as a sensor in practical applications. At the same time, the chiral rare earth supramolecular helix of this embodiment shows good solubility in a variety of organic solvents (such as tetrahydrofuran, acetonitrile, methanol, ethanol, etc.), making it easier to be deviceized in practical applications, thereby simplifying the traditional complex preparation process.

[0056] 3. The chiral rare-earth supramolecular helix of this embodiment benefits from the unique axial chirality of the basic raw material binaphthol. As a chiral unit with both rigidity and flexibility, chiral binaphthol endows the chiral rare-earth supramolecular helix with strong structural rigidity, which is conducive to improving its stability in solution. However, when the chiral rare-earth supramolecular helix interacts with chiral amine, the chiral amine molecule is very likely to perturb the dihedral angle of the chiral binaphthol unit. Moreover, the spectral signal (g lum value) of the dissymmetry factor on the chiral rare-earth supramolecular helix of this embodiment is extremely sensitive to the change of the dihedral angle of the chiral binaphthol unit. Therefore, the sensitivity and accuracy of the chiral rare-earth supramolecular helix of this embodiment in spectral detection are greatly improved.

[0057] 4. The chiral rare-earth supramolecular helix of this embodiment senses chiral amine through the open space on the periphery of the helix, enhancing the contact probability between the chiral amine molecule to be detected and the chiral rare-earth supramolecular helix, and further effectively improving the sensitivity and accuracy of the chiral rare-earth supramolecular helix in sensing chiral amine. Moreover, the synthesis method of the chiral rare-earth supramolecular helix of this embodiment is relatively simple and the synthesis cost is low, making large-scale industrial application possible.

[0058] Specific Embodiment 3: The difference between this embodiment and Specific Embodiment 2 is that the mass fraction of sodium hydride in the mixture of sodium hydride and kerosene described in Step 1 is 60%.

[0059] Specific Embodiment 4: The difference between this embodiment and Specific Embodiment 2 is that the concentration of the Na2CO3 aqueous solution described in Step 2 is 2 mol / L.

[0060] Specific Embodiment 5: The difference between this embodiment and Specific Embodiment 2 is that the volume ratio of absolute ethanol to dichloromethane described in Step 2 is 5:1.

[0061] Specific Embodiment 6: The difference between this embodiment and Specific Embodiment 2 is that in the acetonitrile solution of Eu(OTf)3 described in Step 4, the mass fraction of Eu(OTf)3 in Eu(OTf)3 is 60 - 80%.

[0062] Specific Embodiment 7: The difference between this embodiment and Specific Embodiment 2 is that the mass fraction of tetramethylammonium hydroxide in the aqueous solution of tetramethylammonium hydroxide described in Step 4 is 25%.

[0063] Specific Embodiment 8: The chiral rare-earth supramolecular helix complex of this embodiment is used for the detection of chiral amine, and the detection method is carried out according to the following steps:

[0064] 1. Mix a chiral rare-earth supramolecular helical complex with a test solvent to obtain a solution of the chiral rare-earth supramolecular helical complex. Under the excitation of light at 375 nm, measure the spectroscopic signal value of the luminescence dissymmetry factor (g lum ) of the solution of the chiral rare-earth supramolecular helical complex;

[0065] 2. Mix the solution of the analyte to be measured with the solution of the chiral rare-earth supramolecular helical complex obtained in step 1 to obtain a mixed solution. Under the excitation of light at 375 nm, measure the spectroscopic signal value of the luminescence dissymmetry factor (g lum ) of the mixed solution;

[0066] The analyte in the solution of the analyte to be measured is (R,R)-cyclohexanediamine or (S,S)-cyclohexanediamine;

[0067] The molar ratio of the analyte to be measured to the chiral rare-earth supramolecular helix is (0.01 - 10):1;

[0068] 3. Compare the spectroscopic signal value of the luminescence dissymmetry factor of the mixed solution obtained in step 2 with the spectroscopic signal of the luminescence dissymmetry factor of the solution of the chiral rare-earth supramolecular helical complex obtained in step 1, and realize the qualitative determination and enantiomeric composition detection of a pair of enantiomers of chiral amines through the change of the spectroscopic signal value of the luminescence dissymmetry factor (g lum ).

[0069] 1. The chiral rare-earth supramolecular helical complex in this embodiment can accurately distinguish the enantiomers of chiral amines. The secondary helical structure generated by the chiral rare-earth supramolecular luminescent probe due to the chirality of the ligand endows it with specific recognition ability for chiral amines in space. At the same time, the coordination unit of the chiral ligand can undergo a weak reaction with the chiral amine. Combining the cooperative specific recognition of the chiral amine by the chiral ligand and the helical structure of the chiral rare-earth supramolecule, the dissymmetry factor spectroscopic signal (g lum value) of the chiral rare-earth supramolecule helix changes. Therefore, the enantiomers of chiral amines can be distinguished by detecting the change of the g lum value.

[0070] 2. The chiral rare-earth supramolecule in this embodiment has a helical structure with four ligands. The eight oxygen atoms on the four β-diketone coordination units form a relatively compact and stable eight-coordination environment with the rare-earth ions, which effectively improves its stability as a sensor in practical applications. At the same time, the chiral rare-earth supramolecular helix in this embodiment shows good solubility in various organic solvents (such as tetrahydrofuran, acetonitrile, methanol, ethanol, etc.), making it easier to be device-ized in practical applications, thereby simplifying the traditional complex preparation process.

[0071] 3. The chiral rare-earth supramolecular helix of this embodiment benefits from the unique axial chirality of the basic raw material binaphthol. As a chiral unit with both rigidity and flexibility, chiral binaphthol endows the chiral rare-earth supramolecular helix with strong structural rigidity, which is conducive to improving its stability in solution. However, when the chiral rare-earth supramolecular helix interacts with chiral amines, the chiral amine molecules are very likely to perturb the dihedral angle of the chiral binaphthol unit, and the spectral signal of the dissymmetry factor (g lum value) of the chiral rare-earth supramolecular helix of this embodiment is extremely sensitive to the change of the dihedral angle of the chiral binaphthol unit. Therefore, the sensitivity and accuracy of the chiral rare-earth supramolecular helix of this embodiment in spectral detection are greatly improved.

[0072] 4. The chiral rare-earth supramolecular helix of this embodiment senses chiral amines through the open space on the periphery of the helix, enhancing the contact probability between the chiral amine molecules to be detected and the chiral rare-earth supramolecular helix, and further effectively improving the sensitivity and accuracy of the chiral rare-earth supramolecular helix in sensing chiral amines. Moreover, the synthesis method of the chiral rare-earth supramolecular helix of this embodiment is relatively simple and the synthesis cost is low, making large-scale industrial application possible.

[0073] Specific Embodiment Nine: The difference between this embodiment and Specific Embodiment Eight is that: the concentration of the chiral rare-earth supramolecular helix complex solution in Step 1 is 1×10 -6 ~1×10 -2 mol / L.

[0074] Specific Embodiment Ten: The difference between this embodiment and Specific Embodiment Eight is that: the test solvent in Step 1 is acetonitrile, methanol or tetrahydrofuran. BRIEF DESCRIPTION OF THE DRAWINGS

[0075] Figure 1 It is a graph showing the change of the spectral signal of the dissymmetry factor (g lum value) of the chiral rare-earth supramolecular helix after the tetrahydrofuran solution of the prepared chiral rare-earth supramolecular helix complex interacts with chiral (R,R)-cyclohexanediamine and (S,S)-cyclohexanediamine respectively.

[0076] Example 1:

[0077] The structural formula of the chiral rare-earth supramolecular helix complex of the present invention is:

[0078]

[0079] The general structural formula of the chiral rare-earth supramolecular helix complex is Ln2L4, which is a chiral rare-earth complex composed of a chiral ligand L and a rare-earth element; the structural formula of the chiral ligand L is:

[0080]

[0081] The preparation method of the above chiral rare earth supramolecular helical complex is carried out according to the following steps:

[0082] Step 1: Synthesis of S-(+)-2,2'-dimethoxy-1,1'-binaphthalene:

[0083] Weigh 2 g of the mixture of sodium hydride and kerosene and dissolve it in a mixed solvent of 120 mL of tetrahydrofuran and 80 mL of N,N-dimethylformamide to obtain a sodium hydride solution;

[0084] Weigh 6 g of S-binaphthol and dissolve it in 30 mL of tetrahydrofuran solvent, and then drop it into the sodium hydride solution under an ice-water bath. When no gas escapes after stirring, add 8 g of methyl iodide dropwise to the reaction solution and continuously stir at room temperature for 24 hours; after the reaction is complete, pour the reaction solution into 220 mL of water to quench it, and filter to obtain the crude product S-(+)-2,2'-dimethoxy-1,1'-binaphthalene; the crude product is recrystallized and purified in acetonitrile solvent to obtain S-(+)-2,2'-dimethoxy-1,1'-binaphthalene; S-(+)-2,2'-dimethoxy-1,1'-binaphthalene is a light gray granular crystal with a yield of 75%;

[0085] The mass fraction of sodium hydride in the mixture of sodium hydride and kerosene is 60%;

[0086] Step 2: Synthesis of S-(+)-2,2'-dimethoxy-1,1'-binaphthalene-3,3'-diboronic acid:

[0087] Under nitrogen protection, dissolve 8 mL of tetramethylethylenediamine and 18 mL of n-butyllithium in 120 mL of anhydrous ether, and continuously stir at room temperature for 30 minutes, then add 6 g of S-(+)-2,2'-dimethoxy-1,1'-binaphthalene, and continue to stir at room temperature for 3 h to obtain a light brown suspension; cool the suspension to -78 °C, and then drop 20 mL of triethyl borate into the suspension. After the addition, restore the reaction solution to room temperature and continue to stir for 12 hours; after the reaction is completed, pour the reaction solution into a 5% NaOH aqueous solution and stir until it is completely clear; then use dichloromethane for reverse extraction, collect the aqueous layer, adjust the pH of the aqueous layer to 2 - 3 with dilute hydrochloric acid, filter the precipitated white precipitate and wash it with 40 mL of water, and dry to obtain S-(+)-2,2'-dimethoxy-1,1'-binaphthalene-3,3'-diboronic acid; S-(+)-2,2'-dimethoxy-1,1'-binaphthalene-3,3'-diboronic acid is a white solid with a yield of 71%;

[0088] Step 3. Synthesis of S-(+)-2,2'-dimethoxy-3,3'-bis(4,4',4''-trifluoro-1,3-dioxobutyl)phenyl-1,1'-binaphthalene:

[0089] Under nitrogen protection, weigh 8 g of S-(+)-2,2'-dimethoxy-1,1'-binaphthalene-3,3'-diboronic acid, 8 g of 3-bromoacetophenone, and 3 g of Pd(PPh3)4, dissolve them in 120 mL of tetrahydrofuran, and heat to reflux. After refluxing, add 60 mL of Na2CO3 aqueous solution, and continue the reaction for 24 hours. After the reaction is completed, cool the reaction mixture to room temperature, extract with ethyl acetate, collect the organic layer, dry and filter, then distill off the ethyl acetate under reduced pressure to obtain the crude product. The crude product is recrystallized from a mixed solution of absolute ethanol and dichloromethane to obtain S-(+)-2,2'-dimethoxy-3,3'-bis(4,4',4''-trifluoro-1,3-dioxobutyl)phenyl-1,1'-binaphthalene; it is a white blocky crystal with a yield of 50%;

[0090] The concentration of the Na2CO3 aqueous solution is 2 mol / L;

[0091] The volume ratio of the absolute ethanol to dichloromethane is 5:1;

[0092] Step 4. Synthesis of ligand L:

[0093] Weigh 0.8 g of sodium methoxide and 4 g of ethyl heptafluorobutyrate, dissolve them in 40 mL of dimethyl ether, then add 1.5 g of S-(+)-2,2'-dimethoxy-3,3'-bis(4,4',4''-trifluoro-1,3-dioxobutyl)phenyl-1,1'-binaphthalene, and react at room temperature for 24 hours. After the reaction is complete, pour the reaction solution into water and adjust the pH of the solution to 2–3 with hydrochloric acid to precipitate a solid. Filter to obtain the crude product. Wash and dry the obtained crude product to obtain ligand L; the yield is 73.10%;

[0094] Step 5. Preparation of chiral rare-earth supramolecular helical complex Ln2L4:

[0095] Weigh 0.2 g of ligand L and 0.1 g of aqueous tetramethylammonium hydroxide, dissolve them in 15 mL of acetonitrile, and stir until the solution is clear. Dropwise add an acetonitrile solution of 0.06 g of Eu(OTf)3 to the reaction solution, and stir at room temperature for 24 hours. After the reaction is complete, pour the reaction solution into water to precipitate a solid, and filter to obtain the chiral rare-earth supramolecular helical complex Ln2L4; Ln2L4 is a white solid with a yield of 82%;

[0096] The mass fraction of Eu(OTf)3 in the Eu(OTf)3 acetonitrile solution is 80%;

[0097] The mass fraction of tetramethylammonium hydroxide in the aqueous solution of tetramethylammonium hydroxide is 25%;

[0098] The Eu2L4 prepared in Example 1 was characterized by X-ray single crystal diffraction: To further characterize the accurate structure of the chiral rare earth supramolecular helix, 7 mg of the complex Ln2L4 was dissolved in 6 mL of chloroform, and the single crystal of Ln2L4 was obtained by evaporating the chloroform solution at room temperature. The specific results are shown in Table 1; the data in Table 1 indicate that the target product Eu2L4 was obtained in this example.

[0099] Table 1. Crystallographic parameters of Eu2L4

[0100]

[0101] The above chiral rare earth supramolecular helix complex is used for the detection of chiral amines, and the detection method is carried out according to the following steps:

[0102] I. Mix the chiral rare earth supramolecular helix complex with the test solvent to obtain a chiral rare earth supramolecular helix complex solution; under the excitation of light at 375 nm, the luminescence dissymmetry factor spectral signal value (g lum ) of the chiral rare earth supramolecular helix complex solution was measured;

[0103] The concentration of the chiral rare earth supramolecular helix complex solution is 1×10 -5 mol / L;

[0104] The test solvent is tetrahydrofuran;

[0105] II. Mix the solution to be measured with the chiral rare earth supramolecular helix complex solution obtained in step I to obtain a mixed solution, and measure the luminescence dissymmetry factor spectral signal value (g lum ) of the mixed solution under the excitation of light at 375 nm;

[0106] The solution to be measured is a (R,R)-cyclohexanediamine solution with a concentration of 1×10 -5 mol / L and a (S,S)-cyclohexanediamine solution with a concentration of 1×10 - 5 mol / L;

[0107] The molar ratio of the analyte to the chiral rare earth supramolecular helix is 5:1;

[0108] III. Compare the luminescence dissymmetry factor spectral signal value of the mixed solution obtained in step II with the luminescence dissymmetry factor spectral signal of the chiral rare earth supramolecular helix complex solution obtained in step I, and distinguish a pair of enantiomers of chiral amines through the change of the luminescence dissymmetry factor spectral signal value (g lum ); The results are as followsFigure 1 as shown; by Figure 1 it can be seen that the maximum value of the asymmetry factor of the chiral rare-earth supramolecular helix is located at 592.5 nm; Figure 1 it can be seen from [reference] that in the tetrahydrofuran solution of the chiral rare-earth supramolecular helix, chiral amines with different chiral configurations were gradually added. The two chiral analytes caused different changes in the asymmetry factor signal of the chiral rare-earth supramolecular helix complex. The chiral cyclohexanediamine with the R configuration enhanced the asymmetry factor signal of the chiral rare-earth supramolecular helix complex. However, due to the mismatch between the chiral structure of the S - configuration cyclohexanediamine and the helical chirality of the chiral rare-earth supramolecular helix complex, the chiral rare-earth supramolecular helix complex could not specifically recognize the S - configuration cyclohexanediamine. Therefore, the S - configuration cyclohexanediamine had almost no effect on the asymmetry factor signal value of the chiral rare-earth supramolecular helix complex. According to the changes in the asymmetry factor signal value of the chiral rare-earth supramolecular helix complex caused by the differential recognition of the chiral amine configuration, the two chiral configurations of the chiral amine can be accurately distinguished.

Claims

1. A chiral rare earth supramolecular helical complex, characterized in that: The structural formula of the chiral rare earth supramolecular helical complex is as follows: The general structural formula of the chiral rare earth supramolecular helical complex is Ln2L4, which is a chiral rare earth complex composed of the chiral ligand L and rare earth elements; the structural formula of the chiral ligand L is as follows:

2. The preparation method of the chiral rare earth supramolecular helical complex according to claim 1, characterized in that: The preparation method of the chiral rare earth supramolecular helical complex is carried out according to the following steps: Step 1: Synthesis of S-(+)-2,2'-dimethoxy-1,1'-binaphthalene: Weigh 2 - 3 g of a mixture of sodium hydride and kerosene and dissolve it in a mixed solvent of 100 - 150 mL of tetrahydrofuran and 60 - 100 mL of N,N-dimethylformamide to obtain a sodium hydride solution; Weigh 5 - 8 g of S-binaphthol and dissolve it in 20 - 50 mL of tetrahydrofuran solvent, then drop it into the sodium hydride solution under an ice-water bath. When no gas escapes after stirring, add 7 - 10 g of methyl iodide dropwise to the reaction solution and continuously stir at room temperature for 24 hours; after the reaction is complete, pour the reaction solution into 200 - 250 mL of water to quench it, and filter to obtain the crude product S-(+)-2,2'-dimethoxy-1,1'-binaphthalene; the crude product is recrystallized and purified in acetonitrile solvent to obtain S-(+)-2,2'-dimethoxy-1,1'-binaphthalene; Step 2: Synthesis of S-(+)-2,2'-dimethoxy-1,1'-binaphthalene-3,3'-diboronic acid: Under nitrogen protection, dissolve 7 - 10 mL of tetramethylethylenediamine and 18 - 20 mL of n-butyllithium in 100 - 150 mL of anhydrous ether, and continuously stir at room temperature for 30 minutes. Then add 5 - 8 g of S-(+)-2,2'-dimethoxy-1,1'-binaphthalene and continue to stir at room temperature for 3 h to obtain a light brown suspension; cool the suspension to -78 °C, and then drop 18 - 20 mL of triethyl borate into the suspension. After the addition is complete, restore the reaction solution to room temperature and continue to stir for 12 hours; after the reaction ends, pour the reaction solution into a 5% NaOH aqueous solution and stir until it is completely clear; then perform reverse extraction with dichloromethane, collect the aqueous layer, adjust the pH of the aqueous layer to 2 - 3 with dilute hydrochloric acid, filter the precipitated white precipitate and wash it with 30 - 50 mL of water, and dry to obtain S-(+)-2,2'-dimethoxy-1,1'-binaphthalene-3,3'-diboronic acid; Step 3: Synthesis of S-(+)-2,2'-dimethoxy-3,3'-bis(4,4',4”-trifluoro-1,3-dioxobutyl)phenyl-1,1'-binaphthalene: Under nitrogen protection, 8 - 10 g of S-(+)-2,2'-dimethoxy-1,1'-binaphthalene-3,3'-diboronic acid, 8 - 10 g of 3-bromoacetophenone and 2 - 5 g of Pd(PPh3)4 were weighed and dissolved in 100 - 150 mL of tetrahydrofuran, and the mixture was heated to reflux. After refluxing, 50 - 60 mL of aqueous Na2CO3 solution was added, and the reaction was continued for 24 hours. After the reaction was completed, the reaction mixture was cooled to room temperature and extracted with ethyl acetate. The organic layer was collected, dried, filtered, and then the ethyl acetate was removed by distillation under reduced pressure to obtain a crude product. The crude product was recrystallized from a mixed solution of anhydrous ethanol and dichloromethane to obtain S-(+)-2,2'-dimethoxy-3,3'-bis(4,4',4”-trifluoro-1,3-dioxobutyl)phenyl-1,1'-binaphthalene; Step 4: Synthesis of ligand L: 0.7 - 0.9 g of sodium methoxide and 3 - 5 g of ethyl heptafluorobutyrate were weighed and dissolved in 30 - 50 mL of dimethyl ether. Then 1 - 2 g of S-(+)-2,2'-dimethoxy-3,3'-bis(4,4',4”-trifluoro-1,3-dioxobutyl)phenyl-1,1'-binaphthalene was added, and the reaction was carried out at room temperature for 24 hours. After the reaction was complete, the reaction solution was poured into water and the pH of the solution was adjusted to 2 - 3 with hydrochloric acid to precipitate a solid. The solid was filtered to obtain a crude product, and the obtained crude product was washed with water and dried to obtain ligand L; Step 5: Preparation of chiral rare-earth supramolecular helical complex Ln2L4: 0.2 - 0.5 g of ligand L and 0.1 - 0.3 g of aqueous tetramethylammonium hydroxide solution were weighed and dissolved in 10 - 20 mL of acetonitrile, and the solution was stirred until clear. The acetonitrile solution of 0.06 - 0.07 g of Eu(OTf)3 was added dropwise to the reaction solution, and the mixture was stirred at room temperature for 24 hours. After the reaction was complete, the reaction solution was poured into water to precipitate a solid, and the chiral rare-earth supramolecular helical complex Ln2L4 was obtained by filtration.

3. The preparation method of the chiral rare earth supramolecular helical complex according to claim 2, wherein: The mass fraction of sodium hydride in the mixture of sodium hydride and kerosene described in Step 1 is 60%.

4. The preparation method of the chiral rare earth supramolecular helical complex according to claim 2, characterized in that: The concentration of the aqueous Na2CO3 solution described in Step 2 is 2 mol / L.

5. The preparation method of the chiral rare earth supramolecular helical complex according to claim 2, characterized in that: The volume ratio of anhydrous ethanol to dichloromethane described in Step 2 is 5:

1.

6. The preparation method of the chiral rare earth supramolecular helical complex according to claim 2, characterized in that: In the Eu(OTf)3 acetonitrile solution described in Step 4, the mass fraction of Eu(OTf)3 in Eu(OTf)3 is 60 - 80%.

7. The preparation method of the chiral rare earth supramolecular helical complex according to claim 2, characterized in that: The mass fraction of tetramethylammonium hydroxide in the aqueous tetramethylammonium hydroxide solution described in Step 4 is 25%.

8. Use of the chiral rare earth supramolecular helical complex according to claim 1, characterized in that: The chiral rare-earth supramolecular helical complex is used for the detection of chiral amines, and the detection method is carried out according to the following steps:

1. Mix a chiral rare-earth supramolecular helical complex with a test solvent to obtain a solution of the chiral rare-earth supramolecular helical complex; under the excitation of light at 375 nm, measure the spectral signal value of the luminescence asymmetry factor (g lum ) of the solution of the chiral rare-earth supramolecular helical complex; II. Mix the analyte solution with the chiral rare-earth supramolecular helical complex solution obtained in Step I to obtain a mixed solution, and measure the luminescence dissymmetry factor spectral signal value (g lum ) of the mixed solution under the excitation of light at 375 nm; The analyte in the analyte solution is (R,R)-cyclohexanediamine or (S,S)-cyclohexanediamine; The molar ratio of the analyte to the chiral rare-earth supramolecule is (0.01 - 10):1; III. Compare the luminescence dissymmetry factor spectral signal value of the mixed solution obtained in Step II with the luminescence dissymmetry factor spectrum of the chiral rare-earth supramolecular helical complex solution obtained in Step I, and qualitatively analyze a pair of enantiomers of the chiral amine and detect the enantiomeric composition by the change in the luminescence dissymmetry factor spectral signal value (g lum ).

9. Use of the chiral rare earth supramolecular helical complex according to claim 8, characterized in that: The concentration of the chiral rare earth supramolecular helical complex solution described in Step 1 is 1×10 -6 ~1×10 -2 mol / L.

10. Use of the chiral rare earth supramolecular helical complex according to claim 8, characterized in that: The test solvent described in Step 1 is acetonitrile, methanol or tetrahydrofuran.

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