A square amine functionalized zirconium-based metal-organic cage and its preparation method and application

Abstract

The present invention discloses a square amine functionalized zirconium-based metal-organic cage and its preparation method and application, which belongs to the technical field of catalytic materials. 4+ As a node, 4,4'-((3,4-dioxo-1-ene-1,2-diyl)bis(azanediyl))dibenzoic acid is used as an organic ligand and prepared by a solvent thermal method. The chemical formula is: {[M m Cp n (μ3‑O) p (μ2‑OH) q ] b (L) d}·Cl f (DEF) g ,M is the metal ion Zr 4+ , Cp is cyclopentadiene, L is 4,4'-((3,4-dioxo-1-ene-1,2-diyl)bis(azanediyl))dibenzoic acid, DEF is N,N-diethylformamide, m=3, n=3, p=1, q=3, b=2, d=3, f=2, g=4. It can catalyze the cycloaddition reaction of CO2 and epoxides under mild catalytic conditions, with high efficiency and good cyclic stability.

Description

Technical Field

[0001] The present invention belongs to the technical field of catalytic materials, and in particular relates to a square amine functionalized zirconium-based metal-organic cage and a preparation method and application thereof. Background Art

[0002] CO2 is a major greenhouse gas, and CO2 emission reduction, especially negative emission, is one of the fundamental paths to achieving carbon neutrality. From the perspective of green chemistry and atom economy, the cycloaddition of CO2 to epoxides to produce cyclic carbonates is very promising because this reaction has a 100% atomic utilization rate and does not produce any by-products. However, the high diffusivity and kinetic inertness of CO2 gas have always restricted its application in catalytic conversion, so it is crucial to achieve the conversion of CO2 under mild conditions.

[0003] Zirconium-based metal-organic cages (Zr-MOCs) are assembled from Zr3O clusters and organic linkers. They are structurally similar to metal-organic frameworks (MOFs), except that they have capping groups that prevent unlimited extension into the network. The excellent dispersibility and unique discrete structure of Zr-MOCs make it easier to introduce Lewis acidic active centers, and their strong Zr-O bonds impart excellent stability. However, reports on Zr-MOCs as heterogeneous catalysts for promoting reactions are limited. Therefore, the development of Zr-MOCs with high catalytic activity through the design of rational building blocks remains challenging.

[0004] Recently, hydrogen bonding (HB) catalysis based on squarylamines has played a vital role in improving catalytic activity; however, the widespread application of squarylamines in homogeneous catalysis is limited by their self-aggregation through strong hydrogen bonding interactions. Summary of the Invention

[0005] The purpose of the present invention is to provide a square amine functionalized zirconium-based metal-organic cage and its preparation method and application. The square amine functionalized zirconium-based metal-organic cage is used for chemical fixation of CO2 under mild conditions.

[0006] The present invention provides a square amine functionalized zirconium-based metal-organic cage (Zr-DBDA), the chemical formula of which is: {[M m Cp n (μ3-O) p (μ2-OH) q ] b (L) d}·Cl f (DEF) g , where M is the metal ion Zr 4+, Cp is cyclopentadiene, L is 4,4'-((3,4-dioxo-1-ene-1,2-diyl)bis(azanediyl))dibenzoic acid, DEF is N,N-diethylformamide, m=3, n=3, p=1, q=3, b=2, d=3, f=2, g=4.

[0007] Furthermore, Zr-DBDA is lantern-shaped, and its chemical formula is: {[M m Cp n (μ3-O) p (μ2-OH) q ] b (L) d}·Cl f (DEF) g ,in,

[0008] L is an organic linking ligand H2dbda, whose structural formula is shown in Formula I;

[0009]

[0010] Cp is cyclopentadiene, and its structural formula is shown in Formula II;

[0011]

[0012] M is the metal ion Zr 4+ ;

[0013] DEF is N,N-diethylformamide;

[0014] m, n, p, q, b, d, f and g are metal ions, cyclopentadiene (Cp), oxygen anions (O 2- ), hydroxide ions (OH - ), the number of organic linking ligands (H2dbda), chloride ions and DEF, wherein m=3, n=3, p=1, q=3, b=2, d=3, f=2, g=4.

[0015] A method for preparing a square amine functionalized zirconium-based metal-organic cage, using metal ion Zr 4+ As the node, 4,4'-((3,4-dioxo-1-ene-1,2-diyl)bis(azanediyl))dibenzoic acid was used as the organic ligand to prepare square amine-functionalized zirconium-based metal-organic cages by a solvothermal method.

[0016] Furthermore, the preparation method of the square amine functionalized zirconium-based metal-organic cage comprises the following steps:

[0017] 4,4'-((3,4-dioxo-1-ene-1,2-diyl)bis(azanediyl))dibenzoic acid and a soluble salt of zirconium are mixed, a mixed solvent of N,N-diethylformamide and water is added, and the mixture is stirred evenly. The mixture is reacted at a constant temperature of 55°C to 65°C for 10h to 15h. After the reaction is completed, the mixture is cooled to obtain light yellow block crystals, which are then filtered, washed and dried in sequence to obtain a square amine-functionalized zirconium-based metal-organic cage.

[0018] Furthermore, the molar ratio of 4,4′-((3,4-dioxo-1-ene-1,2-diyl)bis(azanediyl))dibenzoic acid to the soluble salt of zirconium is 1:(2.0-2.3).

[0019] Furthermore, the soluble zirconium salt is zirconocene dichloride.

[0020] Furthermore, the volume ratio of N,N-diethylformamide to water is 1:0.3-0.5.

[0021] Furthermore, the drying temperature is 85° C. to 100° C., and the drying time is 8 hours to 10 hours.

[0022] The application of the square amine functionalized zirconium-based metal-organic cage in chemical fixation of CO2.

[0023] The square amine functionalized zirconium-based metal-organic cage can be used as a catalytic material for catalyzing the cycloaddition reaction of CO2 and epoxide.

[0024] This invention addresses the technical challenges of prior art by incorporating squarylamine groups into Zr-MOCs through a two-in-one strategy, potentially enabling the construction of robust and efficient catalysts. This strategy combines the advantages of squarylamine-based HB catalysis and ZrO cluster-based Lewis acid (LA) catalysis within a single crystal to drive dual activation while simultaneously preventing squarylamine deactivation due to self-aggregation, thereby improving catalytic efficiency and recyclability.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] The starting raw materials used in the present invention are low-cost and environmentally friendly; the target material is synthesized through a one-step solvent thermal reaction, with high yield, simple preparation process, and easy large-scale preparation.

[0027] The square amine functionalized zirconium-based metal-organic cage of the present invention is a novel metal-organic cage with a lantern-shaped structure and excellent stability.

[0028] The square amine functionalized zirconium-based metal-organic cage of the present invention has dual catalytic functions of hydrogen bonding and Lewis acid, and as a heterogeneous catalytic material, has high catalytic activity and is easy to separate products. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The accompanying drawings, which constitute part of the present invention, are provided to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are provided to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0030] Figure 1 Schematic diagram of the structure of the metal-organic cage Zr-DBDA prepared in Examples 1-4 of the present invention;

[0031] Figure 2 This is a curve showing the change in yield of CO2 and epibromopropane over time catalyzed by the metal-organic cage Zr-DBDA and its components prepared in Example 1 of the present invention;

[0032] Figure 3 Figures 1 and 2 are graphs showing the recycling of CO2 and epibromohydrin catalyzed by the metal-organic cage Zr-DBDA prepared in Example 1 of the present invention. (a) is a graph showing the yield of five cycles of catalysis by the metal-organic cage Zr-DBDA. (b) is an X-ray powder diffraction pattern of the synthesized Zr-DBDA and the Zr-DBDA after five cycles of catalysis, simulated from single crystal data of the metal-organic cage Zr-DBDA.

[0033] Figure 4 This is an infrared spectrum of the metal-organic cage Zr-DBDA prepared in Example 1 of the present invention and its adsorption of epibromohydrin;

[0034] Figure 5 3d (right) and N1s (left) XPS spectra of the metal-organic cage Zr-DBDA prepared in Example 1 of the present invention and its adsorption of epibromohydrin. DETAILED DESCRIPTION

[0035] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0036] It should be understood that the terms described herein are intended only to describe particular embodiments and are not intended to limit the present invention. In addition, for numerical ranges herein, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. The intermediate value within any stated value or stated range, and each smaller range between any other stated value or intermediate value within the stated range, is also encompassed within the present invention. The upper and lower limits of these smaller ranges may be independently included or excluded within the scope.

[0037] Unless otherwise indicated, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein may also be used in the practice or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of any conflict with any incorporated document, the contents of this specification shall prevail.

[0038] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments described herein without departing from the scope or spirit of the invention. Other embodiments will be apparent to those skilled in the art from the description of the invention. The description and examples are intended to be exemplary only.

[0039] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0040] Unless otherwise specified, the raw materials and reagents used in the following examples are conventional commercially available drugs.

[0041] In the embodiments of the present invention, unless otherwise specified, room temperature refers to 25±2°C.

[0042] Example 1

[0043] 0.06 mmol of 4,4'-((3,4-dioxo-1-ene-1,2-diyl)bis(azanediyl))dibenzoic acid and 0.12 mmol of zirconocene dichloride were weighed and placed in a 10 mL glass sample bottle. 6 mL of a mixed solvent of DEF and water (volume ratio of 1:0.4) was added. The glass sample bottle was then placed in an electric blast drying oven at a constant temperature of 60°C for 12 h. After the reaction was completed, the reaction was cooled to obtain light yellow block crystals, which were filtered, washed, and dried at 90°C for 9 h to obtain a square amine-functionalized zirconium-based metal-organic cage Zr-DBDA with the chemical formula {[M m Cp n (μ3-O) p (μ2-OH) q ] b (L) d}·Cl f (DEF) g , where M is the metal ion Zr 4+, Cp is cyclopentadiene, L is 4,4'-((3,4-dioxo-1-ene-1,2-diyl)bis(azanediyl))dibenzoic acid, DEF is N,N-diethylformamide, m=3, n=3, p=1, q=3, b=2, d=3, f=2, g=4, yield: 73%, its crystal structure is as follows Figure 1 As shown, from Figure 1 It can be seen that Zr-DBDA has a lantern-shaped cage structure with two vertices. The entire M6L3 framework carries a positive charge, and the cationic charge is replaced by Cl - balance.

[0044] Catalytic Performance Test of Zr-DBDA for Cycloaddition Reaction of CO2 and Epoxides

[0045] The catalyst (0.94 μmol), cocatalyst TBABr (0.07 mmol), reaction substrate (3.3 mmol) and magnetic stirrer were placed in a 10 mL Shrek tube. A balloon filled with 1 atm CO2 was placed on the upper end of the tube. The reactor was placed on a magnetic stirrer and stirred at room temperature for 10 h. After the reaction, the catalyst was separated by centrifugation and the mixture was dried over a 50-well plate. 1 The upper reaction mixture was analyzed by H-NMR to calculate the reaction yield. The catalyst here refers to the zirconium-based metal-organic cage Zr-DBDA, the organic ligand L, zirconocene dichloride, or a mixture of zirconocene dichloride and the organic ligand L (the mass ratio of zirconocene dichloride to the organic ligand L is 1.65:1). Figure 2 The yield curve of the catalytic reaction of CO2 and epibromohydrin over time shows that the reaction is complete after 10 hours, with a yield of 99%. However, the yield of the reaction catalyzed by its components is much lower than that of the metal-organic cage Zr-DBDA.

[0046] Under room temperature, CO2 atmospheric pressure, and a reaction time of 10 h, substrate expansion was carried out on epoxides. The results are shown in Table 1. It can be seen that for smaller catalytic substrates, Zr-DBDA exhibited good catalytic activity with a yield of up to 99%. As the molecular size of the epoxide substrate increased, the yield of cyclic carbonates decreased significantly, showing a certain degree of size-selective catalysis.

[0047] Table 1 Cycloaddition reaction of CO2 with epoxides catalyzed by Zr-DBDA

[0048]

[0049]

[0050] aReaction conditions: Catalyst Zr-DBDA (0.94 μmol), epoxide (3.3 mmol), CO2 (1 atm), and butylammonium bromide (0.07 mmol) were stirred at room temperature for 10.0 h.

[0051] Recycling test of the catalytic performance of Zr-DBDA for the cycloaddition reaction of CO2 and epoxides

[0052] After the catalytic reaction of CO2 and epibromohydrin was completed, Zr-DBDA was filtered, washed three times with dichloromethane, and dried under vacuum at room temperature. Then, the Zr-DBDA was used as a catalyst for the second catalytic experiment. The third, fourth, and fifth experiments were carried out in the same manner. The relevant catalytic results are shown in Figure 2. Figure 3 As shown in (a), it can be seen that Zr-DBDA also showed high catalytic activity after five cycles of use, with almost no decrease in yield, indicating that the material has good catalyst stability and can be recycled at least five times. Figure 3 As can be seen in (b), the solid catalyst recovered from the catalytic reaction exhibits the same powder X-ray diffraction (PXRD) pattern as the original solid Zr-DBDA, clearly supporting the stability of Zr-DBDA during the catalytic reaction and indicating that the catalytic reaction is indeed heterogeneous.

[0053] Infrared Adsorption Test of Epibromohydrin by Zr-DBDA

[0054] 5 mg of the activated Zr-DBDA material prepared in Example 1 was weighed and dispersed in a 20 mM methanol solution of epibromohydrin for one day. The solid was then centrifuged and washed several times with methanol and dried at room temperature. FT-IR analysis of Zr-DBDA and its epibromohydrin-adsorbed sample was performed. The results are shown in Table 1. Figure 4 , Zr-DBDA after adsorption of epibromohydrin is at 1221.1cm -1 and 943.2cm -1 The characteristic stretching vibration peak of three-membered cyclic ether appeared at 1226 cm. Importantly, the stretching vibration peak of free epibromohydrin three-membered cyclic ether was observed to increase from 1226 cm to 1226 cm in the infrared comparison before and after adsorption. -1 to 1221.1cm -1 and from 948.1cm -1 to 943.2cm -1 A significant red shift occurred. The results showed that epibromohydrin and the skeleton of Zr-DBDA were adsorbed and interacted.

[0055] XPS spectra of Zr 3d and N1s of Zr-DBDA and its adsorption of epibromohydrin

[0056] from Figure 5It can be seen from the graph that after adsorption of epibromopropane, the Zr 3d peak shifted from 182.3eV to 182.5eV and from 184.6eV to 184.8eV. At the same time, the N 1s peak also shifted from 400.2eV to 400.4eV. This difference in shifts indicates that the Zr in Zr-DBDA 4+ There is a weak bond interaction between the central / square amine-NH and epibromohydrin, which reduces the electron density around the N and Zr atoms. These results indicate that the pores of Zr-DBDA can adsorb epibromohydrin and 4+ The -NH of the center and square amine activates it.

[0057] Example 2

[0058] 0.06 mmol of 4,4'-((3,4-dioxo-1-ene-1,2-diyl)bis(azanediyl))dibenzoic acid and 0.135 mmol of zirconium dichloride were weighed and placed in a 10 mL glass sample bottle. 6 mL of a mixed solvent of DEF and water (volume ratio of 1:0.4) was added. The glass sample bottle was then placed in an electric blast drying oven at a constant temperature of 65°C for 10 h. After the reaction was completed, the reaction was cooled to obtain light yellow block crystals, which were filtered, washed, and dried at 90°C for 10 h to obtain the metal-organic cage material Zr-DBDA, whose chemical formula is also {[M m Cp n (μ3-O) p (μ2-OH) q ] b (L) d}·Cl f (DEF) g , where M is the metal ion Zr 4+ , Cp is cyclopentadiene, L is 4,4'-((3,4-dioxo-1-ene-1,2-diyl)bis(azanediyl))dibenzoic acid, DEF is N,N-diethylformamide, m=3, n=3, p=1, q=3, b=2, d=3, f=2, g=4, yield: 74%, its crystal structure is as follows Figure 1 shown.

[0059] Example 3

[0060] 0.06 mmol of 4,4'-((3,4-dioxo-1-ene-1,2-diyl)bis(azanediyl))dibenzoic acid and 0.125 mmol of zirconium dichloride were weighed and placed in a 10 mL glass sample bottle. 6 mL of a mixed solvent of DEF and water (volume ratio of 1:0.5) was added. The glass sample bottle was then placed in an electric blast drying oven at a constant temperature of 55°C for 15 h. After the reaction was completed, the reaction was cooled to obtain light yellow block crystals, which were filtered, washed, and dried at 85°C for 10 h to obtain the metal-organic cage material Zr-DBDA, whose chemical formula is also {[M m Cp n (μ3-O) p (μ2-OH) q ] b (L) d}·Cl f (DEF) g , where M is the metal ion Zr 4+ , Cp is cyclopentadiene, L is 4,4'-((3,4-dioxo-1-ene-1,2-diyl)bis(azanediyl))dibenzoic acid, DEF is N,N-diethylformamide, m=3, n=3, p=1, q=3, b=2, d=3, f=2, g=4, yield: 72%, its crystal structure is as follows Figure 1 shown.

[0061] Example 4

[0062] 0.06 mmol of 4,4'-((3,4-dioxo-1-ene-1,2-diyl)bis(azanediyl))dibenzoic acid and 0.13 mmol of zirconium dichloride were weighed and placed in a 10 mL glass sample bottle. 6 mL of a mixed solvent of DEF and water (volume ratio of 1:0.3) was added. The glass sample bottle was then placed in an electric blast drying oven at a constant temperature of 60°C for 13 h. After the reaction was completed, the reaction was cooled to obtain light yellow block crystals, which were filtered, washed, and dried at 100°C for 8 h to obtain the metal-organic cage material Zr-DBDA, whose chemical formula is also {[M m Cp n (μ3-O) p (μ2-OH) q ] b (L) d}·Cl f (DEF) g , where M is the metal ion Zr 4+, Cp is cyclopentadiene, L is 4,4'-((3,4-dioxo-1-ene-1,2-diyl)bis(azanediyl))dibenzoic acid, DEF is N,N-diethylformamide, m=3, n=3, p=1, q=3, b=2, d=3, f=2, g=4, yield: 74%, its crystal structure is as follows Figure 1 shown.

[0063] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A square amine functionalized zirconium-based metal-organic cage, characterized in that: The chemical formula is: {[M m Cp n ( μ 3-O) p ( μ 2-OH) q ] b (L) d }·Cl f (DEF) g , where M is the metal ion Zr 4+ , Cp is cyclopentadiene, L is 4,4'-((3,4-dioxo-1-cyclobutene-1,2-diyl)bis(imino))dibenzoic acid, DEF is N,N-diethylformamide, m=3, n=3, p=1, q=3, b=2, d=3, f=2, g=4; The preparation method of the square amine functionalized zirconium-based metal-organic cage comprises the following steps: 4,4'-((3,4-dioxo-1-cyclobutene-1,2-diyl)bis(imino))dibenzoic acid and a soluble salt of zirconium are mixed, a mixed solvent of N,N-diethylformamide and water is added, and the mixture is stirred evenly. The mixture is reacted at a constant temperature of 55°C to 65°C for 10 to 15 hours. After the reaction is completed, the mixture is cooled to obtain light yellow block crystals, which are then filtered, washed, and dried in sequence to obtain a square amine-functionalized zirconium-based metal-organic cage. The soluble salt of zirconium is zirconocene dichloride.

2. A method for preparing the square amine functionalized zirconium-based metal-organic cage according to claim 1, characterized in that: The following steps are involved: 4,4'-((3,4-dioxo-1-cyclobutene-1,2-diyl)bis(imino))dibenzoic acid and a soluble salt of zirconium are mixed, a mixed solvent of N,N-diethylformamide and water is added, and the mixture is stirred evenly. The mixture is reacted at a constant temperature of 55°C to 65°C for 10 to 15 hours. After the reaction is completed, the mixture is cooled to obtain light yellow block crystals, which are then filtered, washed, and dried in sequence to obtain a square amine-functionalized zirconium-based metal-organic cage. The soluble salt of zirconium is zirconocene dichloride.

3. The method for preparing a square amine functionalized zirconium-based metal-organic cage according to claim 2, characterized in that: The molar ratio of 4,4'-((3,4-dioxo-1-cyclobutene-1,2-diyl)bis(imino))dibenzoic acid to the soluble salt of zirconium is 1:(2.0-2.3).

4. The method for preparing a square amine functionalized zirconium-based metal-organic cage according to claim 2, characterized in that: The volume ratio of N,N-diethylformamide and water is 1: (0.3~0.5).

5. The method for preparing a square amine functionalized zirconium-based metal-organic cage according to claim 2, characterized in that: The drying temperature is 85° C. to 100° C., and the drying time is 8 h to 10 h.

6. Use of the square amine functionalized zirconium-based metal-organic cage according to claim 1 in catalyzing the cycloaddition reaction of CO2 and epoxide.

Images