Chiral MOFs material and preparation method thereof

Abstract

The application provides a kind of chiral MOFs material and preparation method thereof, it is related to chiral metal-organic framework material technical field.The preparation method of the chiral MOFs material includes the following steps: 1,2-cyclohexane diamine, triethylamine, oxalyl chloride monoethyl ester and organic solvent are mixed, and intermediate product is obtained by reaction;Under alkaline condition, intermediate product is first hydrolyzed and then acidified to obtain chiral carboxylic acid ligand;Chiral carboxylic acid ligand, 4,4'-dipyridyl, N,N-dimethylformamide, transition metal salt and water are mixed, and chiral MOFs material is obtained by reaction.The application provides a new chiral MOFs material and preparation method thereof for the problems of poor structure controllability, not easy to process, high cost and poor durability of existing induced framework chirality method, and the obtained material has permanent pore and uniform chiral space, and good stability in acidic phosphate buffer solution.

Description

Technical Field

[0001] This invention relates to the field of metal-organic framework materials technology, and more particularly to a chiral MOF material and its preparation method. Background Technology

[0002] Metal-organic frameworks (MOFs) are formed by ligands connecting to metals or metal clusters, resulting in periodically arranged framework structures. By introducing asymmetric properties into the framework, chiral MOFs can be further obtained. In recent years, chiral MOFs have attracted considerable attention from researchers due to their inherent chirality, permanent porosity, and unique physical properties. Their good stability and inherent chiral structure make chiral MOFs ideal for various applications requiring asymmetric properties, such as asymmetric catalysis, enantiomeric separation, enantiomeric detection, and advanced optical devices.

[0003] Currently, methods for constructing chiral MOFs mainly fall into two categories: using chiral ligands and inducing framework chirality. The chiral ligand method is primarily limited by the availability and high cost of chiral sources, resulting in a lack of material diversity. Inducing framework chirality, on the other hand, lacks structural controllability. Furthermore, shortcomings such as difficulty in processing, high cost, and poor durability further limit the practical application of chiral MOF materials.

[0004] Therefore, it is of great significance to provide a novel chiral MOF material that is simple to prepare, low in cost, and has a stable structure. Summary of the Invention

[0005] The purpose of this invention is to provide a chiral MOF material and its preparation method, so as to solve the problems of poor structural controllability, difficulty in processing, high cost and poor durability of existing methods for inducing chirality of frameworks.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0007] This invention provides a method for preparing chiral MOF materials, comprising the following steps:

[0008] 1) Mix 1,2-cyclohexanediamine, triethylamine, and oxaloyl chloride monoethyl ester with an organic solvent and react to obtain an intermediate product;

[0009] 2) The intermediate product obtained in step 1) is subjected to hydrolysis under alkaline conditions. After the hydrolysis is completed, it is acidified to obtain the chiral carboxylic acid ligand.

[0010] 3) The chiral carboxylic acid ligand, 4,4'-bipyridine, N,N-dimethylformamide, transition metal salt, and water prepared in step 2) are mixed and reacted to obtain chiral MOF materials.

[0011] Preferably, the mass ratio of 1,2-cyclohexanediamine, triethylamine, monoethyl oxalyl chloride to the organic solvent in step 1) is 1:1 to 5:1 to 6:25 to 45.

[0012] Preferably, the 1,2-cyclohexanediamine in step 1) is (1R,2R)-cyclohexane-1,2-diamine or (1S,2S)-cyclohexane-1,2-diamine;

[0013] Organic solvents include one or more of dichloromethane, acetonitrile, and tetrahydrofuran.

[0014] Preferably, the reaction temperature in step 1) is -5 to 20°C, the reaction time is 6 to 12 hours, and the reaction atmosphere is an inert atmosphere.

[0015] Preferably, the hydrolysis reaction in step 2) is to mix the intermediate product obtained in step 1) with an alkali and a solvent and then react them.

[0016] The ratio of intermediate product to alkali and solvent is 1 mol: 1-5 mol: 2-7 L;

[0017] Alkalis include one or more of sodium hydroxide, potassium hydroxide, and lithium hydroxide;

[0018] The solvent for the hydrolysis reaction is a mixture of alcohol and water.

[0019] Preferably, the hydrolysis reaction in step 2) is carried out at a temperature of 85–95°C and for a time of 8–16 hours.

[0020] The pH value of the acidified system is ≤1.

[0021] Preferably, the molar ratio of the chiral carboxylic acid ligand, 4,4'-bipyridine, and transition metal salt in step 3) is 1:0.5-2:0.5-4;

[0022] The ratio of N,N-dimethylformamide, water, and chiral carboxylic acid ligand is 7-13 L: 30-45 L: 1 mol.

[0023] Preferably, the transition metal salt in step 3) is nickel sulfate or copper chloride.

[0024] Preferably, the reaction temperature in step 3) is 80–120°C, and the reaction time is 1–5 days.

[0025] The present invention also provides a chiral MOF material prepared by the above preparation method.

[0026] The present invention has at least the following beneficial effects:

[0027] The chiral MOFs material of this invention possesses permanent pores and a uniform chiral space, exhibiting excellent stability in acidic phosphate buffer solutions. Its aqueous stability lays a solid foundation for its future application research. Attached Figure Description

[0028] Figure 1 The coordination mode diagram of 4,4'-bipyridine in the chiral S-Ni-MOFs material prepared in Example 1 is shown.

[0029] Figure 2 This is a coordination pattern diagram of the chiral carboxylic acid ligands in the chiral S-Ni-MOFs material prepared in Example 1;

[0030] Figure 3 The image shows the three-dimensional structure of the chiral S-Ni-MOFs material prepared in Example 1.

[0031] Figure 4 Thermogravimetric analysis curves of the chiral S-Ni-MOFs material prepared in Example 1;

[0032] Figure 5 Thermogravimetric analysis curves of the chiral S-Cu-MOFs material prepared in Example 7;

[0033] Figure 6 The XRD patterns of the chiral S-Ni-MOFs material prepared in Example 1 after immersion in a phosphate buffer solution with a pH of 3.5 for different durations are shown.

[0034] Figure 7 The XRD patterns of the chiral S-Cu-MOFs material prepared in Example 7 after immersion in a phosphate buffer solution with a pH of 3.5 for different durations are shown.

[0035] Figure 8 The results show the detection of L / D histidine enantiomers using the chiral S-Cu-MOFs material prepared in Example 7. Detailed Implementation

[0036] This invention provides a method for preparing chiral MOF materials, comprising the following steps:

[0037] 1) Mix 1,2-cyclohexanediamine, triethylamine, and oxaloyl chloride monoethyl ester with an organic solvent and react to obtain an intermediate product;

[0038] 2) The intermediate product obtained in step 1) is subjected to hydrolysis under alkaline conditions. After the hydrolysis is completed, it is acidified to obtain the chiral carboxylic acid ligand.

[0039] 3) The chiral carboxylic acid ligand, 4,4'-bipyridine, N,N-dimethylformamide, transition metal salt, and water prepared in step 2) are mixed and reacted to obtain chiral MOF materials.

[0040] In this invention, the preferred method for mixing 1,2-cyclohexanediamine, triethylamine, oxaloyl chloride monoethyl ester and organic solvent in step 1) is to first dissolve 1,2-cyclohexanediamine and triethylamine in a portion of the organic solvent to prepare a mixed solution, and then dissolve oxaloyl chloride monoethyl ester in the remaining organic solvent to prepare an oxaloyl chloride monoethyl ester solution, and then add the mixed solution dropwise to the oxaloyl chloride monoethyl ester solution.

[0041] In this invention, step 1) also includes a step of separating and purifying the intermediate product. The specific operation steps are as follows: after the reaction is completed, the reaction is quenched with saturated NaHCO3 solution, the mixture after the reaction is extracted and separated with dichloromethane, the organic phase is dried with anhydrous sodium sulfate, and then rotary evaporation and silica gel column purification are performed in sequence.

[0042] In this invention, the eluent for silica gel column purification is petroleum ether and ethyl acetate in a volume ratio of 1:1.

[0043] In this invention, the mass ratio of 1,2-cyclohexanediamine, triethylamine, monoethyl oxalyl chloride and organic solvent in step 1) is 1:1 to 5:1 to 6:25 to 45, preferably 1:2 to 4:2 to 5:30 to 40, and more preferably 1:3 to 4:3 to 4:34 to 36.

[0044] In this invention, the 1,2-cyclohexanediamine mentioned in step 1) is (1R,2R)-cyclohexane-1,2-diamine or (1S,2S)-cyclohexane-1,2-diamine.

[0045] In this invention, the organic solvent includes one or more of dichloromethane, acetonitrile, and tetrahydrofuran.

[0046] In this invention, the reaction temperature in step 1) is -5 to 20°C, preferably -3 to 15°C, more preferably -1 to 10°C, and even more preferably 0 to 5°C; the reaction time is 6 to 12 hours, preferably 7 to 10 hours, and even more preferably 8 to 9 hours; the reaction atmosphere is an inert atmosphere, specifically one or more of nitrogen atmosphere, helium atmosphere, and argon atmosphere.

[0047] In this invention, after acidification in step 2), the following steps are also included: filtering and washing with water 2 to 4 times, and drying.

[0048] In this invention, the hydrolysis reaction in step 2) is to mix the intermediate product obtained in step 1) with an alkali and a solvent and then react them.

[0049] In this invention, the ratio of the intermediate product to the alkali and solvent is 1 mol: 1-5 mol: 2-7 L, preferably 1 mol: 2-4 mol: 3-6 L, and more preferably 1 mol: 2-3 mol: 4-5 L.

[0050] In this invention, the alkali includes one or more of sodium hydroxide, potassium hydroxide, and lithium hydroxide.

[0051] In this invention, the solvent for the hydrolysis reaction is a mixture of alcohol and water, wherein the alcohol includes one or more of methanol, ethanol and propanol, and the volume ratio of alcohol to water is 1:1. Water as a solvent helps the hydrolysis reaction to proceed, while the addition of alcohol helps to improve the solubility of the reactants.

[0052] In this invention, the temperature of the hydrolysis reaction in step 2) is 85-95°C, preferably 88-92°C, and more preferably 90°C; the time of the hydrolysis reaction is 8-16 hours, preferably 10-14 hours, and more preferably 12-13 hours.

[0053] In this invention, the acidification is preferably carried out by adding acid to the system after the hydrolysis reaction is completed to adjust the pH value and complete the acidification process.

[0054] In this invention, the pH value of the system after adding acid is ≤1, preferably 0.1 to 1, and more preferably 0.3 to 0.5.

[0055] In this invention, the structural formula of the chiral carboxylic acid ligand is as follows:

[0056] In this invention, after the reaction in step 3) is completed, the process further includes sequential steps of filtration, alcohol washing 4 to 6 times, and drying.

[0057] In this invention, the molar ratio of the chiral carboxylic acid ligand, 4,4'-bipyridine and transition metal salt in step 3) is 1:0.5-2:0.5-4, preferably 1:0.8-1.8:1-3.5, more preferably 1:1-1.5:1.5-3.5, and even more preferably 1:1.2:2-3.

[0058] In this invention, the addition ratio of N,N-dimethylformamide, water and chiral carboxylic acid ligand is 7-13L:30-45L:1mol, preferably 9-11L:35-42L:1mol, and more preferably 10L:38-40L:1mol.

[0059] In this invention, the transition metal salt mentioned in step 3) is nickel sulfate or copper chloride.

[0060] In this invention, the reaction temperature in step 3) is 80-120°C, preferably 85-110°C, more preferably 90-105°C, and even more preferably 95-100°C; the reaction time is 1-5 days, preferably 2-4 days, and even more preferably 3 days.

[0061] The present invention also provides a chiral MOF material prepared by the above preparation method.

[0062] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0063] Example 1

[0064] (1) Under argon protection, 4.57 g of (1S,2S)-cyclohexane-1,2-diamine and 18.0 mL of triethylamine were dissolved in 100 mL of anhydrous dichloromethane to obtain a colorless and transparent mixed solution; then 20 mL of anhydrous dichloromethane solution containing 11.3 g of oxaloyl chloride monoethyl ester was added dropwise to the solution; after the addition was completed, the mixture was stirred at 0 °C for 12 h to obtain a pale yellow solid-liquid mixture; after quenching the reaction with saturated NaHCO3 solution, the yellow organic phase was extracted and separated with dichloromethane, dried with anhydrous Na2SO4, evaporated to dryness, and purified by silica gel column chromatography (eluent was petroleum ether and ethyl acetate in a volume ratio of 1:1) to obtain intermediate product S-1 (11.6 g, yield 92.3%).

[0065] (2) Dissolve 6.28 g of intermediate product S-1 in a mixed solvent of 50 mL methanol and 50 mL water, then add 2 g sodium hydroxide, heat to 85 °C for hydrolysis reaction, and the reaction ends after 12 h. The pH of the system is adjusted to 1 by hydrochloric acid for acidification treatment. After the treatment, filter and wash with water 3 times and dry (70 °C, 12 h) to obtain chiral carboxylic acid ligand S-H2L (4.23 g, yield 81.9%).

[0066] (3) 25.8 mg of chiral carboxylic acid ligand S-H2L and 15.6 mg of 4,4'-bipyridine were dissolved in 1 mL of N,N-dimethylformamide, and then 26.3 mg of nickel sulfate hexahydrate and 4 mL of water were added. The mixture was heated to 90 °C and reacted for 72 h. After the reaction was completed, the product was filtered, washed 5 times with methanol, and air-dried to obtain chiral S-Ni-MOFs material (23.8 mg, yield 46%).

[0067] The reaction equations for the above reactions are as follows:

[0068]

[0069] The crystal structure data of the chiral S-Ni-MOFs material prepared in this embodiment are shown in Table 1.

[0070] Table 1. Crystal structure data of the chiral S-Ni-MOFs material prepared in Example 1.

[0071]

[0072]

[0073]

[0074] The asymmetric unit cell diagram and three-dimensional structure diagram of the chiral S-Ni-MOFs material prepared in this embodiment are as follows: Figures 1-3 As shown. By Figures 1-3 It is known that nickel ions in chiral S-Ni-MOFs materials are six-coordinated, containing four oxygen atoms from chiral carboxylic acid ligands and two nitrogen atoms from 4,4'-bipyridine ligands. The material obtained in this invention connects transition metal ions into one-dimensional chiral helical chains via chiral carboxylic acid ligands, and then connects the chiral helical chains into a three-dimensional interpenetrating network metal-organic framework material via 4,4'-bipyridine.

[0075] Example 2

[0076] The only difference between this embodiment and Example 1 is that in step (3), the amount of chiral carboxylic acid ligand S-H2L is 0.05 mmol, the amount of 4,4'-bipyridine is 0.10 mmol, and the amount of nickel sulfate hexahydrate is 0.12 mmol.

[0077] Example 3

[0078] The only difference between this embodiment and Embodiment 1 is that the heating reaction temperature in step (3) is 95°C and the time is 3 days.

[0079] Example 4

[0080] (1) Under argon protection, 4.57 g of (1R,2R)-cyclohexane-1,2-diamine and 18.0 mL of triethylamine were dissolved in 100 mL of anhydrous dichloromethane to obtain a colorless and transparent mixed solution; then 20 mL of anhydrous dichloromethane solution containing 11.3 g of oxaloyl chloride monoethyl ester was added dropwise to the solution; after the addition was completed, the mixture was stirred at 0 °C for 12 h to obtain a pale yellow solid-liquid mixture; after quenching the reaction with saturated NaHCO3 solution, the yellow organic phase was extracted and separated with dichloromethane, dried with anhydrous Na2SO4, evaporated to dryness, and purified by silica gel column chromatography (eluent was petroleum ether and ethyl acetate in a volume ratio of 1:1) to obtain intermediate product R-1.

[0081] (2) Dissolve 6.28g of intermediate product R-1 in a mixed solvent of 50mL methanol and 50mL water, add 2g of sodium hydroxide, heat to 85℃ for hydrolysis reaction, and the reaction ends after 12h. Adjust the pH of the system to 1 with hydrochloric acid, filter and wash with water 3 times, and dry (70℃, 12h) to obtain chiral carboxylic acid ligand R-H2L.

[0082] (3) 25.8 mg of chiral carboxylic acid ligand R-H2L and 15.6 mg of 4,4'-bipyridine were dissolved in 1 mL of N,N-dimethylformamide, and then 26.3 mg of nickel sulfate hexahydrate and 4 mL of water were added. The mixture was heated to 90 °C and reacted for 72 h. After the reaction was completed, the product was filtered, washed 5 times with methanol, and air-dried to obtain chiral R-Ni-MOFs material.

[0083] The difference between this embodiment and Example 1 is only that in step (1), (1S,2S)-cyclohexane-1,2-diamine is replaced with (1R,2R)-cyclohexane-1,2-diamine. The crystal structure data of the prepared chiral R-Ni-MOFs material are: tetragonal system, space group P4122, and cell parameters are...

[0084] Example 5

[0085] The only difference between this embodiment and Example 4 is that in step (3), the amount of chiral carboxylic acid ligand R-H2L is 0.02 mmol, the amount of 4,4'-bipyridine is 0.05 mmol, and the amount of nickel sulfate hexahydrate is 0.05 mmol.

[0086] Example 6

[0087] The only difference between this embodiment and embodiment 4 is that the heating reaction temperature in step (3) is 85°C and the time is 2.5 days.

[0088] Example 7

[0089] (1) Under argon protection, 4.57 g of (1S,2S)-cyclohexane-1,2-diamine and 18.0 mL of triethylamine were dissolved in 100 mL of anhydrous dichloromethane to obtain a colorless and transparent mixed solution; then 20 mL of anhydrous dichloromethane solution containing 11.3 g of oxaloyl chloride monoethyl ester was added dropwise to the solution; after the addition was completed, the mixture was stirred at 0 °C for 12 h to obtain a pale yellow solid-liquid mixture; after quenching the reaction with saturated NaHCO3 solution, the yellow organic phase was extracted and separated with dichloromethane, dried with anhydrous Na2SO4, evaporated to dryness, and purified by silica gel column chromatography (eluent was petroleum ether and ethyl acetate in a volume ratio of 1:1) to obtain intermediate product S-1.

[0090] (2) Dissolve 6.28g of intermediate product S-1 in a mixed solvent of 50mL methanol and 50mL water, then add 2g of sodium hydroxide, heat to 85℃ for hydrolysis reaction, and the reaction ends after 12h. Adjust the pH of the system to 1 with hydrochloric acid, filter and wash with water 3 times, and dry (70℃, 12h) to obtain chiral carboxylic acid ligand S-H2L.

[0091] (3) Dissolve 25.8 mg of chiral carboxylic acid ligand S-H2L and 15.6 mg of 4,4'-bipyridine in 1 mL of N,N-dimethylformamide, then add 0.1 mmol of copper chloride dihydrate and 4 mL of water, heat to 90 °C and react for 72 h. After the reaction is complete, filter the product, wash it 5 times with methanol and air dry it to obtain chiral S-Cu-MOFs material.

[0092] The only difference between this embodiment and Example 1 is that in step (3), nickel sulfate hexahydrate is replaced with copper chloride dihydrate. The crystal structure data of the prepared chiral S-Cu-MOFs material are: tetragonal system, space group P43, and cell parameters are as follows:

[0093] Example 8

[0094] The only difference between this embodiment and Example 7 is that in step (3), the amount of chiral carboxylic acid ligand S-H2L is 0.07 mmol, the amount of 4,4'-bipyridine is 0.07 mmol, and the amount of copper chloride dihydrate is 0.07 mmol.

[0095] Example 9

[0096] The only difference between this embodiment and embodiment 7 is that the heating reaction time in step (3) is 2 days.

[0097] Example 10

[0098] (1) Under argon protection, 4.57 g of (1R,2R)-cyclohexane-1,2-diamine and 18.0 mL of triethylamine were dissolved in 100 mL of anhydrous dichloromethane to obtain a colorless and transparent mixed solution; then 20 mL of anhydrous dichloromethane solution containing 11.3 g of oxaloyl chloride monoethyl ester was added dropwise to the solution; after the addition was completed, the mixture was stirred at 0 °C for 12 h to obtain a pale yellow solid-liquid mixture; after quenching the reaction with saturated NaHCO3 solution, the yellow organic phase was extracted and separated with dichloromethane, dried with anhydrous Na2SO4, evaporated to dryness, and purified by silica gel column chromatography (eluent was petroleum ether and ethyl acetate in a volume ratio of 1:1) to obtain intermediate product R-1.

[0099] (2) Dissolve 6.28g of intermediate product R-1 in a mixed solvent of 50mL methanol and 50mL water, add 2g of sodium hydroxide, heat to 85℃ for hydrolysis reaction, and the reaction ends after 12h. Adjust the pH of the system to 1 with hydrochloric acid, filter and wash with water 3 times, and dry (70℃, 12h) to obtain chiral carboxylic acid ligand R-H2L.

[0100] (3) Dissolve 25.8 mg of chiral carboxylic acid ligand R-H2L and 15.6 mg of 4,4'-bipyridine in 1 mL of N,N-dimethylformamide, then add 26.3 mg of copper chloride dihydrate and 4 mL of water, heat to 90 °C and react for 72 h. After the reaction is complete, filter the product, wash it 5 times with methanol and air dry it to obtain chiral R-Cu-MOFs material.

[0101] The only difference between this embodiment and Embodiment 4 is that in step (3), nickel sulfate hexahydrate is replaced with copper chloride dihydrate. The crystal structure data of the prepared chiral R-Cu-MOFs material are: tetragonal system, space group P4122, and cell parameters are as follows. Z = 8.

[0102] Example 11

[0103] The only difference between this embodiment and Example 10 is that in step (3), the amount of chiral carboxylic acid ligand R-H2L is 0.015 mmol, the amount of 4,4'-bipyridine is 0.015 mmol, and the amount of copper chloride dihydrate is 0.015 mmol.

[0104] Example 12

[0105] The only difference between this embodiment and Example 10 is that the heating reaction time in step (2) is 5 days.

[0106] Thermogravimetric analysis and stability tests were performed on the chiral S-Ni-MOFs material prepared in Example 1 and the chiral S-Cu-MOFs material prepared in Example 7, respectively (stability test method: XRD test after immersion in acidic phosphate buffer solution at pH 3.5 for 1-5 days). The results are as follows. Figures 4-7 As shown, where Figure 4 Thermogravimetric analysis curves of the chiral S-Ni-MOFs material prepared in Example 1 are shown. Figure 5 The thermogravimetric analysis curves of the chiral S-Cu-MOFs material prepared in Example 7 are shown in the figure. It can be seen from the figure that the chiral S-Ni-MOFs material has good stability below 300℃ and good stability below 240℃. Figure 6The XRD patterns of the chiral S-Ni-MOFs material prepared in Example 1 after immersion in an acidic phosphate buffer solution at pH 3.5 for different times are shown. Figure 7 The XRD patterns of the chiral S-Cu-MOFs material prepared in Example 7 after immersion in an acidic phosphate buffer solution at pH 3.5 for different times show that both exhibit good stability in acidic PBS aqueous solution.

[0107] The chiral S-Cu-MOFs material prepared in Example 7 was used to recognize histidine enantiomers, and the specific application method is as follows:

[0108] Chiral MOF materials, Nafion D-520 dispersion (5% w / w in water / 1-propanol, ≥1 meq / g, purchased from Alfaesa (China) Chemical Co., Ltd.), and N,N-dimethylformamide were mixed at a ratio of 3 mg: 20 μL: 280 μL, sonicated for 1 h, and settled for 15 min to obtain a stable suspension. The stable suspension was then added dropwise to a carbon paper electrode and air-dried for 24 h to obtain a loaded working electrode.

[0109] The D / L histidine enantiomer was prepared into a 1 mmol / L solution using a 0.01 mol / L phosphate buffer solution at pH 3.5. A three-electrode system was constructed using a loaded working electrode, an Ag / AgCl reference electrode, and a graphite rod counter electrode. Electrochemical tests were performed on the D-type and L-type histidine solutions using linear sweep voltammetry (LSV) at the following conditions: potential range of -1.5 V to 1.5 V, scan rate of 0.05 V / s, and sensitivity of 1 mA.

[0110] Electrochemical recognition results as follows Figure 8 As shown in the figure, the detection electrode loaded with chiral S-Cu-MOFs material exhibits chiral recognition of L-histidine. At a potential of -1.5V, the L-histidine current decreases by 32.5% compared to the background current, and the D-histidine current decreases by 2.4% compared to the background current, indicating that the chiral MOFs material prepared in this invention has a significant chiral recognition effect on histidine enantiomers.

[0111] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. Use of a chiral MOFs material for the recognition of histidine enantiomers, characterized in that, The preparation method of the chiral MOFs material comprises the following steps: 1) mixing 1,2-cyclohexane diamine, triethylamine, oxalyl monomethyl ester and an organic solvent to obtain an intermediate product; 2) hydrolyzing the intermediate product obtained in step 1) under alkaline conditions, and then acidifying to obtain a chiral carboxylic acid ligand; 3) mixing the chiral carboxylic acid ligand obtained in step 2), 4,4'-bipyridine, N,N-dimethylformamide, a transition metal salt and water to obtain the chiral MOFs material; The transition metal salt in step 3) is nickel sulfate or copper chloride; The molar ratio of the chiral carboxylic acid ligand, 4,4'-bipyridine and the transition metal salt in step 3) is 1:0.5-2:0.5-4; The temperature of the reaction in step 3) is 80-120 DEG C, and the reaction time is 1-5 days.

2. Use according to claim 1, characterized in that, The mass ratio of 1,2-cyclohexane diamine, triethylamine, oxalyl monomethyl ester and the organic solvent in step 1) is 1:1-5:1-6:25-45.

3. Use according to claim 2, characterized in that, The 1,2-cyclohexane diamine in step 1) is (1R,2R)-cyclohexane-1,2-diamine or (1S,2S)-cyclohexane-1,2-diamine; The organic solvent comprises one or more of dichloromethane, acetonitrile and tetrahydrofuran.

4. Use according to claim 3, characterized in that, The temperature of the reaction in step 1) is -5-20 DEG C, the reaction time is 6-12 hours, and the reaction atmosphere is inert atmosphere.

5. The use according to any one of claims 1 to 4, characterized in that, The hydrolysis reaction in step 2) is mixing the intermediate product obtained in step 1) with a base and a solvent to obtain the chiral carboxylic acid ligand; The addition ratio of the intermediate product, the base and the solvent is 1 mol:1-5 mol:2-7 L; The base comprises one or more of sodium hydroxide, potassium hydroxide and lithium hydroxide; The solvent of the hydrolysis reaction is a mixture of alcohol and water.

6. Use according to claim 5, characterized in that, The temperature of the hydrolysis reaction in step 2) is 85-95 DEG C, and the hydrolysis reaction time is 8-16 hours.

7. Use according to claim 6, characterized in that, The addition ratio of N,N-dimethylformamide, water and the chiral carboxylic acid ligand in step 3) is 7-13 L:30-45 L:1 mol.

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