Heteroligand zirconium-based metal organic cages, their preparation methods and applications

Abstract

This application relates to anisoligand zirconium-based metal-organic cage, its preparation method, and its application. The preparation method of the anisoligand zirconium-based metal-organic cage includes the following steps: mixing a zirconium source precursor, an L1 ligand precursor, and a solvent; reacting at a reaction temperature for a first time; then adding an L2 ligand precursor; continuing the reaction for a second time to prepare the anisoligand zirconium-based metal-organic cage; the chemical structures of the L1 and L2 ligand precursors are different; the reaction temperature is 30℃~60℃; the first reaction time is 2h~8h; and the solvent includes water. The preparation method has high reproducibility and enables the prepared metal-organic cage to have a stable structure.

Description

Technical Field

[0001] This application relates to metal-organic cage materials, and in particular to an isoligand zirconium-based metal-organic cage, its preparation method, and its application. Background Technology

[0002] Metal-organic cages (MOCs) are a class of discrete, three-dimensional hollow materials formed by the self-assembly of metal nodes and multidentate organic ligands through coordination. Compared with metal-organic frameworks (MOFs), MOCs possess well-defined molecular-level structures, solubility, and highly designable internal cavity environments, giving them unique advantages in catalysis, host-guest chemistry, molecular recognition and separation, and biomedicine. Since the first zirconium-based metal-organic cage (Zr-MOCs) based on the trinuclear zirconium oxide cluster (Zr3O) was reported in 2013, researchers have discovered that Zr(IV) ions have high coordination numbers and extremely strong Zr-O bond energies (766.1 ± 10.6 kJ / mol), thus endowing Zr-MOCs with excellent thermal and chemical stability. This allows them to maintain structural integrity under strong acid, strong base, and aqueous conditions, making them a highly promising material in the current MOC system.

[0003] However, current research and applications of Zr-MOCs mainly focus on single-ligand self-assembly systems. Although these systems are relatively predictable in terms of structure, their internal cavity environment, size, and external surface functional group types are often relatively simple, making it difficult to meet the needs of high-level applications such as multifunctional synergistic catalysis, cascade reactions, or complex molecular recognition.

[0004] To overcome the above shortcomings, introducing two or more ligands with different structures and functions to construct heteroligand Zr-MOCs is considered an effective way to achieve fine control of cage structure and functional integration. Through the heteroligand strategy, it is expected to achieve functions such as coexistence of hydrophobic / hydrophilic sites, synergistic acid-base functions, and spatial isolation between photoelectric active units and catalytic centers within the same cage. However, the construction of heteroligand Zr-MOCs in traditional techniques still faces many key technical challenges: 1) Due to the reversible kinetics of the coordination self-assembly process, the distribution of different ligands in the reaction system is relatively random, making it difficult to achieve precise control of ligand type, ratio, and spatial position, resulting in poor reproducibility of the preparation method; 2) Post-synthetic modification methods can functionalize Zr-MOCs through ligand exchange, chemical reactions of ligand functional groups, etc., but the premise is that the post-modification process cannot destroy the main MOC structure, and it is difficult to achieve precise control of the number and position of the modified ligands. Therefore, there are problems of incomplete and uncontrollable modification and the risk of destroying the main MOC structure. Summary of the Invention

[0005] Based on this, this application provides a highly reproducible method for preparing heteroligand zirconium-based metal-organic cages (Zr-MOCs) with stable structures, as well as the heteroligand zirconium-based metal-organic cages prepared by this method and their applications.

[0006] A first aspect of this application provides a method for preparing anisoligand zirconium-based metal-organic cage, comprising the following steps:

[0007] The zirconium source precursor, L1 ligand precursor and solvent are mixed and reacted at the reaction temperature for a first time. Then, L2 ligand precursor is added and the reaction is continued for a second time to prepare the heteroligand zirconium-based metal-organic cage.

[0008] The L1 ligand precursor has a different chemical structure from the L2 ligand precursor; the reaction temperature is 30℃~60℃; the first reaction time is 2h~8h; and the solvent includes water.

[0009] In one embodiment, the first time is 2h to 6h.

[0010] In one embodiment, the L1 ligand precursor comprises isophthalic acid with at least one R substituent, wherein each R is independently a C3-C6 alkoxy, arylamino, or nitrogen-containing fused ring.

[0011] Optionally, the aromatic amino group is a diphenylamino group;

[0012] Optionally, the nitrogen-containing fused ring is 9,10-dihydroacridinyl, phenoxazinyl, phenthiazinyl, phenthiazine 5,5-dioxideyl, phenselenozinyl, phentellurylyl or carbazoleyl;

[0013] Optionally, the molar ratio of zirconium in the L1 ligand precursor to that in the zirconium source precursor is 1:(2~4).

[0014] In one embodiment, the L2 ligand precursor comprises a linear dicarboxylic acid compound and / or a flexible dicarboxylic acid compound;

[0015] Optionally, the linear dicarboxylic acid compound includes 4,4'-(1,2-ethynediyl)dibenzoic acid;

[0016] Optionally, the flexible dicarboxylic acid compound includes one or both of 3,3'-dithiodibenzoic acid and 4,4'-dithiodibenzoic acid;

[0017] Optionally, the molar ratio of zirconium in the L2 ligand precursor to that in the zirconium source precursor is 1:(1.5~10).

[0018] In one embodiment, the second time is 12h to 72h.

[0019] In one embodiment, the solvent includes water and an organic solvent;

[0020] Optionally, the organic solvent includes one or more of acetonitrile, N,N-dimethylformamide, and N,N-dimethylacetamide;

[0021] Optionally, the volume ratio of the water to the organic solvent is 1:(2~15).

[0022] In one embodiment, the zirconium source precursor includes one or more of zirconium dichloride, zirconium oxychloride, and zirconium alkoxide.

[0023] A second aspect of this application provides an isoligand zirconium-based metal organic cage, the general structural formula of which is shown in formula (I) or formula (II):

[0024] V2(L1)2(L2)1 (I),

[0025] V4(L1)4(L2)2 (II),

[0026] Wherein, V represents a polynuclear zirconium oxide cluster;

[0027] L1 represents L1 ligand, which is derived from isophthalic acid with at least one R substituent, where each R is independently a C3-C6 alkoxy, arylamino, or nitrogen-containing fused ring.

[0028] L2 represents L2 ligands derived from linear dicarboxylic acid compounds and / or flexible dicarboxylic acid compounds.

[0029] In one embodiment, the heteroligand zirconium-based metal-organic cage is prepared by the preparation method described in the first aspect.

[0030] A third aspect of this application provides the preparation of heteroligand zirconium-based metal-organic cages by the preparation method described in the first aspect, and the application of the heteroligand zirconium-based metal-organic cages described in the second aspect in chemical catalysis, photoelectric functional materials, or molecular separation.

[0031] Studies have shown that the timing of the addition of the second ligand (provided by the L2 ligand precursor) significantly affects the stability of the final metal-organic cage structure during the preparation of heteroligand zirconium-based metal-organic cages. This application involves a reaction conducted under specific temperature conditions. First, a stable polynuclear zirconium-oxygen cluster formed from the hydrolysis-condensation reaction of the zirconium source precursor undergoes a coordination reaction with the L1 ligand precursor. Then, the L2 ligand precursor is added after 2-8 hours of reaction to continue the reaction, allowing the L2 ligand to coordinate with the remaining sites in the intermediate. This enables the ordered assembly of the heteroligand within the zirconium-based metal-organic cage structure. This preparation method exhibits good reproducibility, resulting in heteroligand zirconium-based metal-organic cages with well-defined structures, controllable composition, and designable functions. This has significant scientific and industrial value for promoting the application of heteroligand zirconium-based metal-organic cages in chemical catalysis, molecular separation, and optoelectronic functional materials.

[0032] Furthermore, employing L1 and L2 ligand precursors with appropriate structures and performing coordination reactions in sequence is more conducive to achieving the orderly assembly of heteroligands in the cage structure, thereby overcoming the problems of uncontrollable structure and poor reproducibility in the synthesis of zirconium-based metal-organic cages with heteroligands in traditional techniques. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the structure of V2(L1)2(L2)1 and V4(L1)4(L2)2 in one embodiment.

[0034] Figure 2 The single-crystal structures of MOC-diPhN-BPDE (a) and MOC-diPhN-DS (b) synthesized in Examples 1 and 2 are shown.

[0035] Figure 3 The image shows the nuclear magnetic resonance (NMR) spectrum of the MOC-diPhN-BPDE synthesized in Example 1.

[0036] Figure 4 This is a high-resolution mass spectrum of the MOC-diPhN-BPDE synthesized in Example 1.

[0037] Figure 5 The carbon dioxide adsorption-desorption curves of MOC-diPhN, MOC-diPhN-BPDE and MOC-diPhN-DS at different temperatures are compared, where a is -10℃ and b is 20℃. Detailed Implementation

[0038] The following detailed description, in conjunction with specific embodiments, further illustrates the heteroligand zirconium-based metal-organic cage, its preparation method, and its applications. This application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of this application.

[0039] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0040] As used herein, the terms “and / or,” “or / and,” and “and / or” may include any one of two or more of the related listed items, as well as any and all combinations of the related listed items, including any two related listed items, any more related listed items, or a combination of all the related listed items.

[0041] In this article, "one or more" refers to any one, two or more of the listed items.

[0042] In this application, terms such as "first aspect," "second aspect," "third aspect," and "fourth aspect" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or quantity, nor should they be construed as implicitly indicating the importance or quantity of the indicated technical features. Moreover, terms such as "first," "second," "third," and "fourth" serve only as a non-exhaustive enumeration and should be understood not to constitute a closed limitation on quantity.

[0043] In this application, the technical features described in an open-ended manner include both closed technical solutions consisting of the listed features and open technical solutions that include the listed features.

[0044] In this application, numerical ranges are referred to as continuous unless otherwise specified, and include the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Furthermore, when the range refers to integers, it includes every integer between the minimum and maximum values ​​of the range. Additionally, when multiple ranges are provided to describe a feature or characteristic, the ranges may be merged. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges to which they are incorporated.

[0045] Unless otherwise specified, the percentage content mentioned in this application refers to mass percentage for solid-liquid mixtures and solid-phase-solid mixtures, and volume percentage for liquid-phase-liquid mixtures.

[0046] Unless otherwise specified, all percentage concentrations mentioned in this application refer to the final concentration. The final concentration refers to the proportion of the added component in the system after the addition of that component.

[0047] Unless otherwise specified, the temperature parameters in this application may be either constant temperature processing or processing within a certain temperature range. The constant temperature processing allows for temperature fluctuations within the precision range controlled by the instrument.

[0048] In this application, room temperature generally refers to 4℃~30℃, and preferably 20±5℃.

[0049] Some embodiments of this application provide a method for preparing an isoligand zirconium-based metal organic cage, comprising the following steps:

[0050] The zirconium source precursor, L1 ligand precursor and solvent are mixed and reacted at the reaction temperature for a first time. Then, L2 ligand precursor is added and the reaction is continued for a second time to prepare the heteroligand zirconium-based metal-organic cage.

[0051] The L1 ligand precursor has a different chemical structure than the L2 ligand precursor;

[0052] The reaction temperature is 30℃~60℃;

[0053] The first time period is 2 hours to 8 hours.

[0054] The solvent includes water.

[0055] Without limitation, the reaction process of the above preparation method is as follows:

[0056] Under controlled conditions, the zirconium source precursor undergoes hydrolysis and condensation reactions to form a stable polynuclear zirconium oxide cluster. The L1 ligand precursor in the system preferentially coordinates and self-assembles with the polynuclear zirconium oxide cluster to form a structurally stable intermediate that still retains some coordinateable sites. At an appropriate time, the L2 ligand precursor is added to the reaction system. The L2 ligand precursor selectively occupies the remaining or exchangeable coordination sites in the intermediate to obtain a heteroligand zirconium-based metal-organic cage material.

[0057] Understandably, "different chemical structures" means that there are differences in at least one of the two ligand precursor structures, spatial configurations, and functional group types.

[0058] Specifically, the reaction temperature includes, but is not limited to: 30°C, 35°C, 40°C, 45°C, 50°C, 55°C, 60°C, or any range between the two mentioned above.

[0059] Specifically, the first time period includes, but is not limited to, 2h, 3h, 4h, 5h, 6h, 7h, 8h, or any two of the foregoing. Further, the first time period is 2h to 6h.

[0060] In some embodiments, the L1 ligand precursor (whose general formula can be represented as H2L1) can be a polycarboxylic acid ligand with strong structural rigidity and high coordination ability. Further, the L1 ligand precursor includes isophthalic acid with at least one R substituent, where each R is independently a C3-C6 alkoxy, aromatic amino, or nitrogen-containing fused ring. By adjusting the type and size of the R groups, its coordination effect with the polynuclear zirconium oxide cluster can be improved, while also facilitating the acceptance of the L2 ligand precursor by the coordination-formed intermediate.

[0061] Furthermore, the aromatic amino group is a diphenylamino group.

[0062] Further, the nitrogen-containing fused ring is 9,10-dihydroacridinyl, phenoxazinyl, phenthiazinyl, phenthiazin 5,5-dioxideyl, phenselenyl, phentelluryl, or carbazoleyl.

[0063] Furthermore, the L1 ligand precursor can be, for example, 5-(diphenylamino)isophthalic acid.

[0064] Furthermore, the molar ratio of zirconium in the L1 ligand precursor to that in the zirconium source precursor is 1:(2~4). Specifically, this molar ratio includes, but is not limited to: 1:2, 1:2.5, 1:3, 1:3.5, 1:3.75, 1:4, or any range between the two aforementioned.

[0065] In some embodiments, the L2 ligand precursor (whose general formula can be represented as H2L2) comprises linear dicarboxylic acid compounds and / or flexible dicarboxylic acid compounds. By using specific L2 ligand precursors, the structure and molecular flexibility of the aforementioned intermediates can be matched, improving the reproducibility of the preparation method and making the structure of the prepared heteroligand zirconium-based metal-organic cage controllable.

[0066] Understandably, "linear dicarboxylic acid compounds" refer to dicarboxylic acid ligands that contain two carboxyl groups in their molecules, with the coordination directions of the two carboxyl groups arranged in a straight or nearly straight line, and whose molecular skeleton has a rigid, conjugated, and coplanar structure.

[0067] Understandably, "flexible dicarboxylic acid compounds" are a class of dicarboxylic acids with two carboxyl coordination sites, and the carboxyl groups are bridged by flexible groups such as freely rotating single bonds, alkyl chains, thioether bonds, and disulfide bonds.

[0068] Furthermore, the linear dicarboxylic acid compound includes 4,4'-(1,2-ethynediyl)dibenzoic acid.

[0069] Furthermore, the flexible dicarboxylic acid compound includes one or both of 3,3'-dithiodibenzoic acid and 4,4'-dithiodibenzoic acid.

[0070] Further, the molar ratio of zirconium in the L2 ligand precursor to that in the zirconium source precursor is 1:(1.5~10). Specifically, this molar ratio includes, but is not limited to: 1:1.5, 1:1.75, 1:2, 1:2.5, 1:3, 1:3.5, 1:4, 1:4.5, 1:5, 1:5.5, 1:6, 1:6.5, 1:7, 1:7.5, 1:8, 1:8.5, 1:9, 1:9.5, 1:10, or any range between the two aforementioned.

[0071] In some embodiments, the second time is 12h to 72h. Specifically, the second time includes, but is not limited to, 12h, 24h, 36h, 48h, 60h, 72h, or any range between the two mentioned above.

[0072] In some embodiments, the solvent includes water and an organic solvent. Without limitation, the organic solvent includes one or more of acetonitrile, N,N-dimethylformamide, and N,N-dimethylacetamide.

[0073] In some embodiments, the volume ratio of water to organic solvent is 1:(2~15). Specifically, this molar ratio includes, but is not limited to: 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, 1:11, 1:12, 1:13, 1:14, 1:15, or any range between the foregoing.

[0074] In some embodiments, the zirconium source precursor includes one or more of zirconium dichloride, zirconium oxychloride, and zirconium alkoxide.

[0075] Without limitation, the reaction continues for a second time, followed by a post-treatment step of the reaction system to obtain the isoligand zirconium-based metal-organic cage product. As an example, the post-treatment includes cooling the reaction system to room temperature, followed by filtration and washing to obtain the final product.

[0076] In other embodiments of this application, a zirconium-based heteroligand metal organic cage is provided, the general structural formula of which is shown in formula (I) or formula (II):

[0077] V2(L1)2(L2)1 (I),

[0078] V4(L1)4(L2)2 (II),

[0079] Wherein, V represents a polynuclear zirconium oxide cluster;

[0080] L1 represents L1 ligand, which is derived from isophthalic acid with at least one R substituent, where each R is independently a C3-C6 alkoxy, arylamino, or nitrogen-containing fused ring.

[0081] L2 represents L2 ligands derived from linear dicarboxylic acid compounds and / or flexible dicarboxylic acid compounds.

[0082] Understandably, R-substituents, linear dicarboxylic acid compounds, flexible dicarboxylic acid compounds, etc., have the same or similar technical solutions and advantages as the preparation methods described above, and will not be elaborated here.

[0083] Furthermore, the heteroligand zirconium-based metal organic cage is prepared by the preparation method described above.

[0084] As an example, structural diagrams of V2(L1)2(L2)1 and V4(L1)4(L2)2 can be found in [reference]. Figure 1 In this context, the metal vertex V is a stable polynuclear zirconium-oxygen cluster formed after the hydrolysis-condensation reaction of the zirconium source. When L2 is L2-1 (for example, 4,4'-(1,2-ethynyldimethyl)benzoic acid), the two ligands can coordinate to form the V4(L1)4(L2-1)2 structure. When L2 is L2-2 (for example, 3,3'-dithiodibenzoic acid), the two ligands can coordinate to form the V2(L1)2(L2-2)1 structure.

[0085] Other embodiments of this application provide preparation methods as described above to obtain heteroligand zirconium-based metal organic cages, and applications of the heteroligand zirconium-based metal organic cages as described above in chemical catalysis, photoelectric functional materials, or molecular separation.

[0086] Understandably, the heteroligand zirconium-based metal-organic cage is formed through coordination of two ligands, and has good structural stability and good reproducibility in its preparation method. The specific functionalization in its structure gives it a good carbon dioxide adsorption effect, and the cavity features of different sizes and shapes make it promising for applications in the fields of chemical catalysis, molecular separation and optoelectronic functional materials, which has important scientific significance and industrial value.

[0087] For experimental parameters not specified in the following specific embodiments, please refer to the guidelines given in this application document first, or refer to experimental manuals or other experimental methods known in the art, or refer to the experimental conditions recommended by the manufacturer.

[0088] The raw materials and reagents involved in the following specific embodiments can be obtained commercially or prepared by those skilled in the art using known methods.

[0089] Example 1

[0090] This embodiment describes the preparation of a V4(L1)4(L2)2 type heteroligand MOC-diPhN-BPDE, and the steps are as follows:

[0091] S1: Weigh 4.5 mg of zirconium dichlorodecane and 1.5 mg of L1 ligand precursor 5-(diphenylamino)isophthalic acid into a mixed solution of acetonitrile / water (volume ratio 10:1).

[0092] S2: Heat to 45℃, react for 3 hours, add L2 ligand precursor 4,4'-(1,2-ethynediyl)dibenzoic acid (0.6 mg, dissolved in dimethyl sulfoxide solution) and continue the reaction for two more days (48 h).

[0093] S3: Filter the reaction solution, collect the solid, wash and dry it to obtain the target product MOC-diPhN-BPDE, with a yield of 13%.

[0094] The prepared product is a pure crystalline target product, and its single crystal structure is as follows: Figure 2 As shown in Figure a, the nuclear magnetic resonance characterization is as follows: Figure 3 As shown, high-resolution mass spectrometry is as follows Figure 4 As shown. 1 H NMR (400 MHz, MeOD) δ 7.89 (s, 4H), 7.76(d, J = 7.6 Hz, 8H), 7.68 – 7.54 (m, 16H), 7.51 – 7.43 (m, 16H), 7.22 – 7.11(m, 24H), 6.61 (s, 20H), 6.37 (s, 40H). HRMS (ESI) m / z calcd. by IsoPro forC 172 H 137 N4O 40 Zr 12 [M-3H] 2+ : 1997.3824, found: 1997.3818. [M-3H] 3+ : 1331.9242,found: 1331.9244.

[0095] The preparation was repeated three times according to the above steps, with a yield of 13% ± 5%. The product morphology was stable, indicating that the method has high reproducibility.

[0096] Example 2

[0097] This embodiment describes the preparation of a V2(L1)2(L2)1 type heteroligand MOC-diPhN-DS, and the steps are as follows:

[0098] S1: Weigh 4.5 mg of zirconium dichlorodecane and 1.5 mg of L1 ligand precursor 5-(diphenylamino)isophthalic acid into a mixed solution of acetonitrile / water (volume ratio 5:1).

[0099] S2: Heat to 45℃, react for 3 hours, then add L2 ligand precursor 3,3'-dithiodibenzoic acid (2.7 mg, dissolved in dimethyl sulfoxide solution) and continue the reaction for two more days (48 h).

[0100] S3: Filter the reaction solution, collect the solid, wash and dry it to obtain the target product MOC-diPhN-DS, with a yield of 74%.

[0101] The prepared product is a pure crystalline target product, and its single crystal structure is as follows: Figure 2 As shown in b. 1 H NMR (400MHz, DMSO) δ 7.68 (s, 2H), 7.62 – 7.44 (m, 16H), 7.41 – 7.36 (m, 2H), 7.30 (t, J = 7.5 Hz, 4H), 7.19 (d, J = 7.9 Hz, 8H), 7.10 (s, 2H), 6.58 (s, 10H),6.38 (s, 20H). HRMS (ESI) m / z calcd. by IsoPro for C 84 H 69 N2O 20 S2Zr6 [MH] + :2036.8220, found: 2036.8215.

[0102] The preparation was repeated three times according to the above steps, with a yield of 74% ± 5%. The product morphology was stable, indicating that the method has high reproducibility.

[0103] Comparative Example 1

[0104] This comparative example describes the preparation of a V2(L1)2(L2)1 type MOC-diPhN-DS, with the same steps as in Example 2, the main difference being that two ligands are added simultaneously.

[0105] Comparative Example 2

[0106] This comparative example describes the preparation of a MOC-diPhN-DS of the V2(L1)2(L2)1 formula. The steps are the same as in Example 2, except that the timing of the addition of the second ligand is different. Specifically, in step S2, the second ligand is added after heating to 45°C and reacting for 24 hours.

[0107] The products prepared in Comparative Examples 1 and 2 were both mixtures in an amorphous state, and no pure crystalline target product was obtained.

[0108] Comparative Example 3

[0109] This comparative example describes the preparation of a V2(L1)2 type MOC-diPhN, and the steps are as follows:

[0110] S1: Weigh 4.5 mg of zirconium dichlorodecane and 1.5 mg of L1 ligand precursor 5-(diphenylamino)isophthalic acid into a mixed solution of acetonitrile / water (volume ratio 5:1).

[0111] S2: Heat to 45℃ and react for one day (24h).

[0112] S3: Filter the reaction solution, collect the solid, wash and dry it to obtain the target product MOC-diPhN.

[0113] Test case

[0114] This test case examines the CO2 adsorption effect of the materials prepared in Example 1, Example 2, and Comparative Example 3.

[0115] The testing method is as follows:

[0116] (1) Weigh an appropriate amount of the analyte and degas it under vacuum at 80°C for 8 hours to remove the adsorbed gas and solvent molecules.

[0117] (2) Adsorption and desorption tests were conducted at -10℃ and 20℃ using carbon dioxide as the adsorbate to obtain carbon dioxide adsorption effect diagrams of the samples.

[0118] Test results are as follows Figure 5 As shown.

[0119] As can be seen, the V4(L1)4(L2)2 type heteroligand provided in Example 1 has a larger cavity volume and a stronger carbon dioxide adsorption effect compared with the V2(L1)2(L2)1 type heteroligand provided in Example 2 and the monoligand provided in Comparative Example 3. In particular, it can still efficiently capture CO2 under low temperature conditions, making it of great application value in scenarios such as low temperature industrial flue gas purification, natural gas / biogas upgrading, air control in confined spaces, and CO2 capture in extreme low temperature environments.

[0120] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0121] The embodiments described above are merely illustrative of several implementation methods of this application, intended to facilitate a detailed understanding of the technical solutions of this application, but should not be construed as limiting the scope of protection of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the scope of protection of this application. It should be understood that technical solutions obtained by those skilled in the art based on the technical solutions provided in this application through logical analysis, reasoning, or limited experimentation are all within the scope of protection of the appended claims. Therefore, the scope of protection of this patent application should be determined by the content of the appended claims, and the specification can be used to interpret the content of the claims.

Claims

1. A method for preparing an isoligand zirconium-based metal-organic cage, characterized in that, Includes the following steps: The zirconium source precursor, L1 ligand precursor and solvent are mixed and reacted at the reaction temperature for a first time. Then, L2 ligand precursor is added and the reaction is continued for a second time to prepare the heteroligand zirconium-based metal-organic cage. The L1 ligand precursor has a different chemical structure from the L2 ligand precursor; the reaction temperature is 30℃~60℃; the first reaction time is 2h~8h; and the solvent includes water.

2. The method for preparing the heteroligand zirconium-based metal-organic cage according to claim 1, characterized in that, The first time period is 2h~6h.

3. The method for preparing the heteroligand zirconium-based metal-organic cage according to claim 1, characterized in that, The L1 ligand precursor comprises isophthalic acid with at least one R substituent, wherein each R is independently a C3-C6 alkoxy, aromatic amino, or nitrogen-containing fused ring. Optionally, the aromatic amino group is a diphenylamino group; Optionally, the nitrogen-containing fused ring is 9,10-dihydroacridinyl, phenoxazinyl, phenthiazinyl, phenthiazine 5,5-dioxideyl, phenselenozinyl, phentellurylyl or carbazoleyl; Optionally, the molar ratio of zirconium in the L1 ligand precursor to that in the zirconium source precursor is 1:(2~4).

4. The method for preparing the heteroligand zirconium-based metal-organic cage according to claim 1, characterized in that, The L2 ligand precursor includes linear dicarboxylic acid compounds and / or flexible dicarboxylic acid compounds; Optionally, the linear dicarboxylic acid compound includes 4,4'-(1,2-ethynediyl)dibenzoic acid; Optionally, the flexible dicarboxylic acid compound includes one or both of 3,3'-dithiodibenzoic acid and 4,4'-dithiodibenzoic acid; Optionally, the molar ratio of zirconium in the L2 ligand precursor to that in the zirconium source precursor is 1:(1.5~10).

5. The method for preparing the heteroligand zirconium-based metal-organic cage according to any one of claims 1 to 4, characterized in that, The second time period is 12h~72h.

6. The method for preparing the heteroligand zirconium-based metal-organic cage according to any one of claims 1 to 4, characterized in that, The solvents include water and organic solvents; Optionally, the organic solvent includes one or more of acetonitrile, N,N-dimethylformamide, and N,N-dimethylacetamide; Optionally, the volume ratio of the water to the organic solvent is 1:(2~15).

7. The method for preparing the heteroligand zirconium-based metal-organic cage according to any one of claims 1 to 4, characterized in that, The zirconium source precursor includes one or more of zirconium dichloride, zirconium oxychloride, and zirconium alkoxide.

8. A zirconium-based metal-organic cage with heteroligands, characterized in that, Its general structural formula is shown in formula (I) or formula (II): V2(L1)2(L2)1 (I), V4(L1)4(L2)2 (II), Wherein, V represents a polynuclear zirconium oxide cluster; L1 represents L1 ligand, which is derived from isophthalic acid with at least one R substituent, where each R is independently a C3-C6 alkoxy, arylamino, or nitrogen-containing fused ring. L2 represents L2 ligands derived from linear dicarboxylic acid compounds and / or flexible dicarboxylic acid compounds.

9. The heteroligand zirconium-based metal-organic cage according to claim 8, characterized in that, It is prepared by the preparation method described in any one of claims 1 to 7.

10. The preparation method according to any one of claims 1 to 7 yields anisoligand zirconium-based metal organic cage, and the application of the anisoligand zirconium-based metal organic cage according to claim 8 or 9 in chemical catalysis, photoelectric functional materials, or molecular separation.

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