Metal-organic frameworks with node defects and methods of making the same

Abstract

A metal-organic framework is provided by a method comprising reacting a first metal source that can produce a tetravalent metal cation in solution, a linear dicarboxylic acid, a second metal source that can produce a divalent cation in solution, and one or more monobasic carboxylic acid modulators in a solvent to provide a reaction solution. The reaction solution is heated to provide a metal-organic framework having about 0 wt% to 10 wt% divalent cations, a specific surface area of about 1100 m 2 / g to 2700 m 2 / g, a porosity of about 0.45 cc / g to 1.1 cc / g, and a relative intensity equal to or greater than 0.35 and a peak width ratio less than 3.0.

Description

[0001] Cross-references to related applications

[0002] This application claims priority and interest in U.S. Provisional Application No. 63 / 202856, filed June 28, 2021, which is incorporated herein in its entirety. Technical Field

[0003] This invention relates to introducing defects into metal-organic frameworks to increase specific surface area and micropore volume, and more specifically to the synthesis and preparation method of novel metal-organic frameworks having tetravalent cations and terephthalic acid-type linkers. Background Technology

[0004] Metal-organic frameworks (MOFs) are organic connectives that bridge metal nodes through coordination bonds to form coordination networks. The topology of MOFs can be tuned through iso-network expansion or functionalization of organic connectives and metal nodes. These tunable topologies allow MOFs to be tailored for a wide range of applications, from catalytic conversion to adsorption and separation to biomedical applications. However, MOFs are relatively unstable compared to conventional porous silica and alumina.

[0005] The instability of MOFs can be mitigated by introducing trivalent metals such as aluminum, chromium, and iron, or tetravalent metals such as zirconium, hafnium, and titanium. Furthermore, the high connectivity between the resulting metal clusters and the linkers allows for the formation of defects at high concentrations without disrupting the overall structure. Undercoordinated metal ions can act as catalytic active sites or anchoring sites for other active elements.

[0006] Controlling defect formation is crucial for achieving desired performance while maintaining a well-defined and tunable metal-organic framework. To date, the mechanisms controlling the formation of deletion cluster defects (node ​​defects) have not reached the complexity of those controlling deletion linker defects. Although some modulators have proven effective in regulating deletion linker defects, the modulators promoting node defects are limited unless excessively high concentrations are used. Furthermore, some effective modulators, such as fluorinated carboxylic acids, are environmentally undesirable. Summary of the Invention

[0007] This invention provides a metal-organic framework comprising a plurality of tetravalent cations and terephthalic acid-type linkers crystallized in a simple cubic lattice and having a thickness of approximately 1100 μm. 2 / g~2700m 2 Specific surface area per g, porosity of approximately 0.45 cc / g to 1.1 cc / g, and relative strength equal to or greater than 0.35.

[0008] This invention provides a metal-organic framework, which is prepared by a method comprising the following steps: reacting a first metal source capable of generating tetravalent metal cations in solution, a linear dicarboxylic acid, a second metal source capable of generating divalent cations in solution, and one or more monocarboxylic acid modifiers in a solvent to provide a reaction solution; and heating the reaction solution to provide a reaction mixture, wherein the metal-organic framework contains about 0% to 10% by weight of divalent cations and has a specific surface area of ​​about 1100 m². 2 / g~2700m 2 / g, with a porosity of approximately 0.45cc / g to 1.1cc / g, and a relative strength equal to or greater than 0.35 and / or a peak width ratio less than 3.0.

[0009] The present invention also provides a metal-organic framework comprising a plurality of zirconium cations and a plurality of BDC (benzene dicarboxylate) linkers in a simple cubic lattice, and about 0.0 wt% to 10.0 wt% of divalent cations. The metal-organic framework has a specific surface area of ​​about 1100 m². 2 / g~2700m 2 / g, with a porosity of about 0.45cc / g to 1.1cc / g and a relative strength equal to or greater than 0.35, the specific surface area being measured by nitrogen BET.

[0010] The present invention also provides a metal-organic framework comprising a plurality of zirconium cations and BDC linkers in a simple cubic lattice, and less than about 7.0 wt% of divalent cations. In one aspect, under conditions of washing and without impregnation with one or more other cations, as measured by X-ray fluorescence, there are less than or equal to 5.3 wt% or less than or equal to 5.0 wt% of divalent cations. The zirconium-based metal-organic framework has a relative intensity equal to or greater than 0.35 and / or a peak width ratio less than 3.0.

[0011] This invention provides a method for preparing a metal-organic framework, the method comprising the steps of: reacting a precursor metal, metal complex, or metal oxide (i.e., a first metal source), a polyorganocarboxylic acid, a second metal precursor metal, a second metal complex, or a second metal oxide (i.e., a second metal source), and one or more monocarboxylic acids in a solvent to provide a reaction solution; heating the reaction solution to a reaction temperature of at least 75°C to provide a reaction mixture containing a metal-organic framework material; and separating the metal-organic framework material from the reaction mixture. The reaction mixture contains a metal-organic framework material, and the metal-organic framework material comprises a plurality of metal-organic frameworks. Each of the plurality of metal-organic frameworks has a plurality of tetravalent cations and terephthalic acid-type linkers crystallized in a simple cubic lattice, and about 3.0 wt% to about 5.0 wt% of divalent cations, and has a relative strength equal to or greater than 0.35.

[0012] Furthermore, the present invention provides a method for regulating the defective structure or morphology of a metal-organic framework, the method comprising the step of synthesizing the metal-organic framework using a second metal or a second metal cation.

[0013] In one specific embodiment of the invention, the metal-organic framework can primarily have a REO topology, particularly a REO topology with FCU defects. For example, the metal-organic framework can correspond to UiO-66 with high or even complete defects (measured by relative strength reflecting the degree of defect), which can be referred to as a REO-UiO-66 family material. The metal-organic framework of the present invention or prepared by the method of the present invention can also be referred to as EMM-71.

[0014] These and other features and properties of the disclosed methods and systems, as well as their advantageous applications and / or uses, will become clear from the detailed description below. Attached Figure Description

[0015] To assist those skilled in the art in preparing and using the subject matter of this invention, reference is made to the following figures, in which:

[0016] Figure 1A1 , Figure 1A2 , Figure 1A3 , Figure 1A4 , Figure 1B and Figure 1C The powder X-ray diffraction patterns are of UiO-66 samples prepared using conventional synthesis and four different monocarboxylate modifiers with different modifier:BDC ratios.

[0017] Figure 2A1 , Figure 2A2 and Figure 2A3Powder X-ray diffraction patterns of UiO-66 samples synthesized from terephthalic acid, methyl terephthalic acid and amino terephthalic acid are shown. Figure 2B A graph showing the relative intensity of the samples is displayed.

[0018] Figure 3 The powder X-ray diffraction pattern of the sample described in Example 1 is shown.

[0019] Figure 4 The thermogravimetric analysis results of the sample described in Example 1 are shown.

[0020] Figure 5A and Figure 5B These are the nitrogen adsorption isotherms of samples 1 and 2 described in Example 1.

[0021] Figure 6 The X-ray diffraction pattern of Zr-BDC synthesized in the presence of several metal cations is shown.

[0022] Figure 7A and Figure 7B The powder X-ray diffraction patterns of the synthesized Zr-MOF samples are shown as the concentration of acetic acid solution decreases and the concentration of reactants increases, respectively.

[0023] Figure 8 The powder X-ray diffraction pattern of the sample synthesized from nitrates is shown, highlighting that no large defect domains were formed with cobalt or zinc cations in the absence of chloride ions.

[0024] Figure 9 Showing the use of Zn 2+ Powder X-ray diffraction pattern of EMM-71 sample made with cations.

[0025] Figure 10 Nitrogen adsorption is shown in a Zn-BDC sample prepared in the presence of ZnO and treated with sodium formate.

[0026] Figure 11A , Figure 11B and Figure 11C It is a simulated powder X-ray diffraction pattern of missing node domains with varying degrees of residual BDC ligands.

[0027] Figure 12A and Figure 12B This is the nitrogen adsorption isotherm of the Zn-regulated EMM-71 metal-organic framework. Figure 12A In this study, the metal-organic framework was washed with sodium borate (0.25 M) at pH 9 under different temperature conditions. Figure 12B In this study, the metal-organic framework was washed with sodium formate (0.5M) under different time and temperature conditions.

[0028] Figure 13A and Figure 13B This is a scanning electron micrograph of the EMM-71 metal-organic framework synthesized in the presence of zinc (Zn).

[0029] Figure 13C and Figure 13D This is a scanning electron micrograph of the Zr-BDC metal-organic framework synthesized in the presence of cobalt (Co).

[0030] Figure 14 This is the powder X-ray diffraction pattern of the metal-organic framework EMM-71 in Example 2.

[0031] Figure 15 This is the powder X-ray diffraction pattern of the metal-organic framework EMM-71 in Example 3.

[0032] Figure 16 The powder X-ray diffraction pattern of the metal-organic framework Hf-Zr EMM-71 prepared in Example 3 using different molar percentages of Hf in the total Hf-Zr contents.

[0033] Figure 17 The powder X-ray diffraction patterns of the metal-organic framework EMM-71 fractions were captured at 45 minutes, 80 minutes, 120 minutes, 195 minutes and 255 minutes as described in Example 4.

[0034] Figure 18 This is the powder X-ray diffraction pattern of the metal-organic framework EMM-71 in Example 7. Detailed Implementation

[0035] Before disclosing and describing the compounds, components, compositions, and / or methods of the present invention, it should be understood that, unless otherwise stated, the present invention is not limited to specific compounds, components, compositions, reactants, reaction conditions, ligands, catalyst structures, MOF structures, etc., as these can vary, unless otherwise specified. It should also be understood that the terminology used in this invention is for descriptive purposes only and is not intended to be limiting.

[0036] Metal-organic frameworks (MOFs) are constructed from the three-dimensional assembly of metal ions / clusters and organic ligands. Due to their high pore volume, ordered structure, and tunability, MOFs are suitable for a variety of applications such as photocatalysis, catalysis, separation and purification, gas / energy storage, and sensing. High specific surface area and high concentrations of isolated metal ions enhance gas storage capacity and mass transfer.

[0037] Metal-organic frameworks (MOFs) comprise organic linkers (also known as "ligands") that bridge metal nodes (called "secondary building blocks" or "SBUs") via coordination bonds and can self-assemble to form coordination networks. Through iso-network extensions or functionalization of organic linkers / metal nodes, tunable topologies allow MOFs to be tailored for a wide range of applications, from catalytic conversion to adsorption and separation to biomedical applications. MOFs possess properties suitable for industrial applications such as gas adsorption, gas separation, catalysis, heating / cooling, batteries, gas storage, sensing, and environmental remediation.

[0038] The stability of metal-organic frameworks (“MOFs”) can be attributed to the strong interactions between low-polarity ions such as carboxylate ions and trivalent metals. Initially, stable MOFs were attributed to cations derived from trivalent cations, namely Al. 3+ Fe 3+ and Cr 3+ phthalic acid dicarboxylate-based MOFs. Subsequently, other multivalent cations such as Zr 4+ Hf 4+ or Ti 4+ Used to provide an additional robust framework. The metal-organic framework UiO-66 was first discovered through the reaction of zirconium salts with linear dicarboxylic acids. Cavka, JH et al., A New Zirconium Inorganic Building Brick Forming Metal Organic Frameworks with Exceptional Stability, J. Am. Chem. Soc., 130 Vol. 42, No. 13850-13851, 2008.

[0039] At the time of its discovery, UiO-66 possessed the highest connectivity of any known metal-organic framework.

[0040] To enhance the adsorption and catalytic performance of metal-organic frameworks (MOFs), the introduction of defects into MOFs has recently attracted attention. The high connectivity of high-valence metals in MOFs such as UiO-66 provides the potential for generating high levels of defects. Besides offering functional flexibility through the selection of linkers, the high connectivity between the metal cluster and the linkers allows for the formation of defects at high concentrations without disrupting the overall structure. These defects can take the form of organic linker defects or missing node defects, i.e., omissions of the entire metal cluster. As described in this paper, undercoordinated metal ions act as catalytically active sites or anchoring sites for other active elements.

[0041] Missing connector defects are caused by the removal of connectors and the generation of point defects. Missing node defects or node defects are generated by coupling the removal of metal clusters and the connectors connected to the metal clusters. Removing metal clusters and connectors in a concentrated manner forms nanodomains with REO topology. Although both types of defects affect the mechanical and physical properties of the metal-organic framework, cluster removal leaves mesoscopic holes, thus providing a more open hierarchical porous structure that is beneficial for mass and proton transport.

[0042] Controlling defect formation is crucial for achieving the desired properties of metal-organic frameworks while maintaining well-defined and tunable structures. To date, control mechanisms for missing node defects have not reached the complexity of those for missing linker defects. While modifiers have proven useful in controlling missing linker defects, those that promote the formation of missing cluster defects are limited unless excessive concentrations are used. Furthermore, known modifiers such as fluorinated carboxylic acids are environmentally undesirable. Additionally, defect domains are relatively small, as evidenced by the width of the peaks generated by defect domains. Comparatively, missing cluster defects have been more prominent in systems without monocarboxylate regulation and in the presence of water (often with additional hydrochloric acid). (Chammingkwan, P. et al., Modulator-free Approach Towards Missing-cluster Defect Formation in Zr-based UiO-66, RSCAdv., Vol. 10, pp. 28180-28185, 2020.)

[0043] This invention provides a method for synthesizing zirconium terephthalate metal-organic frameworks in an FCU topology (cubic octahedral edge transfer network of cluster-based MOFs), which incorporates controllable domain sizes for missing cluster defects (referred to herein as "node defects") by introducing divalent metal cations, and primarily metal-organic frameworks with an REO topology having FCU defects. The method of this invention produces novel metal-organic frameworks with node defects. Node defects are highly useful in adsorption and catalysis applications. For example, defects can be capped with catalytic moieties that provide additional functionality for grafting catalytic sites. In separation applications, polycyclic cycloalkanes can undergo selective binding, particularly at larger defects, to provide enhanced selectivity (in addition to enhanced diffusion properties) for the separation of polycyclic cycloalkanes.

[0044] As used herein, the term “REO topology” refers to a cubic transit network or topological network of Zr-MOFs, as described in the following references: Chen et al., Reticular Chemistry in the Rational Synthesis of Functional Zirconium Cluster-base MOFs, Coordination Chemistry Reviews, 400, 2019; see also, for example, Chen et al., above, Figure 1 and Figure 4 .

[0045] As used herein, the term “divalent” refers to the oxidation state of a divalent cation, not whether it is part of a charged molecule as a whole (e.g., dissolved and undissociated ZnCl2).

[0046] As described herein, the metal-organic framework of the present invention has a density of approximately 1100 m 2 / g~2700m 2 The specific surface area is approximately 0.45 cc / g to 1.1 cc / g, the porosity is approximately 0.45 cc / g to 1.1 cc / g, and the relative strength is equal to or greater than 0.35. In one aspect, the relative ratio of the peak widths at the half-maximum of these metal-organic frameworks is less than 3. The relative ratio of the peak widths at the half-maximum is equal to the width of peak (110) at half its height divided by the width of peak (111) at half its height. Furthermore, as described herein, the method of manufacturing defective metal-organic frameworks of the present invention produces metal-organic frameworks having divalent cations in an amount less than or equal to 5.0% by weight, for example, from approximately 3.0% by weight to approximately 5.0% by weight in the manufactured material.

[0047] In the conventional synthesis of zirconium MOFs with FCU topology, linear bidentate ligands are dissolved in a polar aprotic solvent, typically dimethylformamide, containing a zirconium source (i.e., zirconyl chloride or zirconium tetrachloride) and a modifier. The modifier can be a monocarboxylic acid such as formic acid, acetic acid, benzoic acid, or trifluoroacetic acid, but can also be water or hydrochloric acid. For example, as... Figure 1A1 , Figure 1A2 , Figure 1A3 , Figure 1A4 , Figure 1B and Figure 1CAs shown in Figure 1, powder X-ray diffraction patterns of the UiO-66 sample were obtained through conventional synthesis using different modifier:BDC (benzene dicarboxylate) ratios for four different monocarboxylate modifiers. See Shearer, GC et al., Defect Engineering: Tuning the Porosity and Composition of the Metal-Organic Framework UiO-66 via modulated Synthesis, Chem. Mater., 28, 11, 3749-3761, 2016. Features centered at 5°2θ represent nanoscale domains of missing node defects (also referred to herein as “REO defects”). Figure 1B As shown, the relative intensity of the feature (which is the integral intensity of the feature (centered at 5°2θ) divided by the average of the intensities of the (111), (200), and (600) peaks) is plotted against the molar equivalent of the modifier used. Figure 1C As shown, a plot of the modifier concentration versus the measured specific surface area of ​​the resulting material is provided. In the work shown, missing clusters / node defects appear as a broad, poorly defined feature ranging from ~3 to 7°2θ. This is a result of the defect domains leading to the appearance of symmetric bandgap peaks. Here, node defects form a simple cubic lattice without systematic defects, while an ideal single crystal has face-centered cubic domains that only show reflections of all additive or even-numbered domains. In a subsequent report, Lillerud demonstrated that HCl modifiers (instead of carboxylic acid modifiers) exhibit more pronounced diffraction peaks associated with node defects. See Shearer et al., Functionalizing the Defects: Postsynthetic Ligand Exchange in the Metal-Organic Framework UiO-66, Chem. Mater., 28, 20, 7190-7193, 2016.

[0048] Building on these earlier reports, Chammingkwan et al. demonstrated that water can effectively generate nodal defects in UiO-66 and its methyl and amino-functionalized analogs when very low water content is used in the synthesis. In all cases where less than 0.5 mL of water was added, equivalent to an H2O:Zr ratio of 14, a small number of domains lacking nodal defects were observed. In all cases, the degree of defect was characterized by comparing the integrated intensity of the wide defect region (in this case, the (110) peak) and dividing that integrated value by the average of the intensities of the (111), (200), and (600) reflections. Figure 2A1 , Figure 2A2 and Figure 2A3The XRD patterns of the unfunctionalized and functionalized UiO-66 are shown, and Figure 2B The relative intensity of the (110) REO peak was plotted using the method of Chammingkwan et al. (refer to Shearer et al., above). Even in the most extreme case, with unfunctionalized UiO-66, the intensity of the (110) peak relative to the average of the (111), (200), and (600) peaks was only about 0.18.

[0049] Unlike earlier methods for creating missing node defects described above, we disclose a more efficient method for generating missing clusters / node defects than previously known. As described in this paper, we show that the introduction of selected divalent metals not only induces node defects, but also induces the generation of missing clusters to a much higher degree compared to existing methods.

[0050] In our study, Sn had a peak width ratio of 3:1, as used herein, which means that the peak width ratio at the (110) peak (originating from REO defects) is three times the width of the (111) peak at its half-maximum. Zirconium and cobalt can produce even smaller ratios, i.e., 1.7 to 1.2. Therefore, the metal-organic framework of the present invention can have peak width ratios at half-maximum of the (110) and (111) peaks that are less than 3, less than 2.5, less than 2, less than 1.75, less than 1.50, or even less than 1.25.

[0051] As described in the examples, we first investigated whether divalent ions could be introduced into the metal-organic framework structure after in-situ oxidation. Although no significant introduction of divalent ions was observed, we observed the presence of amplified diffraction reflections corresponding to the (100) and (110) planes of the REO topology. Similarly, other divalent ions such as magnesium, calcium, and nickel did not produce these same reflections, indicating a lack of missing node defects. Monocationic metals such as lithium also failed to produce the expected reflections. Moreover, the resulting micropore volume was likely smaller than that given by the intensity of the peaks.

[0052] Under the same synthetic conditions described herein, copper(II) chloride exhibited a number of REO domains comparable to those of the metal-organic framework prepared by stannous chloride. On the other hand, strong reflections of the (100) and (110) peaks and (210) and (211) reflections of REO domains were observed in cobalt and zinc chlorides, which are rarely observed in this type of metal-organic framework. Magnesium, lithium, and nickel(2+) showed limited diffraction intensities absent between 4 and 6°2θ.

[0053] In addition to the unexpected role of selecting divalent cations in the formation of missing node defects, we observed that the efficacy of cations can depend on the presence of halide cations in solution. For example, using only nitrates (zirconium nitrate and cobalt / zinc nitrate) does not form defects, and the process becomes reversible by adding HCl or NH4Cl. Although NH4Br can be effective, the oxidation of bromide ions to elemental bromine interferes with the process. Fluorides, on the contrary, lead to the formation of alternating phases, and the addition of ammonium fluoride does not form a metal-organic framework.

[0054] Furthermore, only a small amount of chloride is needed to initiate the REO generation mechanism or the transition from the FCU topology to the REO topology. Non-halide metal modifiers such as zinc oxide (and zinc metal as a divalent zinc source) effectively generate the transition from the FCU topology to the REO topology and the REO domain. In the case of zinc oxide, the oxide reacts with acetic acid in the reaction to produce zinc acetate and water. However, metallic zinc produces flammable gases, and zinc oxide can affect the acidity / alkalinity of the solution.

[0055] The defect-generating cations, measured as M:Zr (or more generally as divalent cation: tetravalent cation), appear to be optimal at approximately 37 wt%. Lower ratios of approximately 25 wt% divalent cations are effective at generating REO defects (referred to as missing clusters or node defects in REO topology), especially when measured by powder X-ray diffraction (“PXRD”). Furthermore, porosity is more easily maximized at slightly higher values. A decay peak is observed when the divalent cation content decreases relative to zirconium (or more generally relative to tetravalent cations) to approximately 10 wt%. No higher effective cobalt concentrations were observed when CoCl2 was used as a modifier. However, ZnO does exhibit an upper limit, likely due to the interference of water or acetate equivalents in domain formation within the REO topology. Excess acetate and high pH can affect the solution processes that provide missing node defects.

[0056] Combined, complex solution-state processes occur prior to nucleation and growth, and the presence of these selected divalent cations disrupts the kinetics of these processes, leading to nodal defects. This is evidenced by the loss of defects if the inorganic components are pre-aged. Defects also appear if ligands are added shortly after the addition of the inorganic reagents to the reaction mixture. With increasing residence time, the reflection of REO topology and associated REO domains decreases. For example, after four (4) hours, no defects may form, suggesting that the additives can delay the formation of specific chemical species in solution, thereby generating FCU domains in the metal-organic framework. In addition to halide concentration, other variables can also affect the degree of defects in the resulting metal-organic framework material, including: (1) acetic acid concentration; (2) water content; (3) reaction temperature; (4) metal / ligand ratio; and (5) divalent dopant content.

[0057] Furthermore, the amount of acetic acid in the reaction medium can affect the reflection intensity of REO domains in the REO topology of PXRD. For example, when the overall concentration of HOAc:BDC is reduced while the overall concentration of acetic acid is maintained, missing node defects can be maintained until the reactant concentration reaches a critical level. This is likely due to the increased concentration of water in the reaction, indicating that not only the molecular proportions of these molecular species are important, but also the solution concentrations of these reactant species are important. When water forms zirconium secondary building blocks, stress is generated because excessively high concentrations lead to a decrease in defect density, requiring an upper limit on the reaction concentration. Moreover, when using hydrated salts, high yields and high defect concentrations are not achieved beyond a certain reaction concentration, regardless of the water concentration. This can be improved by using anhydrous salts such as ZrCl4 or by slowly adding zirconium to the reaction medium. To characterize nanoscale materials, powder X-ray diffraction is described in the editorial of the American Chemical Society, Holder, CF et al., Tutorial on Powder X-ray Diffraction for Characterizing Nanoscale Materials, ACS Nano, 13, 7, 7359-7365, 2019.

[0058] Besides acetic acid and water, we also observed that temperature is an effective variable for synthesizing nodal defect metal-organic frameworks. As observed by Lillerud in his 2014 publication, high-temperature reaction conditions tend to produce materials with lower defect levels. See Shearer et al., Tuned to Perfection: Ironing Out the Defects in Metal–Organic Framework UiO-66, Chem. Mater., 26, 14, 4068-4071, 2014. In this particular work, reaction conditions were screened between 100 °C and 220 °C, with materials synthesized at 220 °C showing almost no defects. The temperature dependence is enhanced in the case of metal-organic frameworks with REO topology. Reactions were carried out between 80 °C and 130 °C, and it was observed that only high levels of defects dominated the PXRD when the reaction was carried out between 90 °C and 100 °C. Below this temperature, a large number of unreacted BDCs are present, and above this temperature, attenuated reflections of REO domains appear.

[0059] Due to the strong reflection from REO domains, we sought to measure the overall contribution of defective domains relative to non-defective FCU domains. To this end, we constructed a material studio model where missing nodes with varying amounts of organic ligands were located on either side of the defect site. We then compared the relative intensities of the (100), (110), (111), and (200) reflections with these models. Figure 11A and Figure 11B As shown, fully defective materials, where each defect is capped with a hydroxyl or water moiety, result in a pattern where the (100) reflection peak is the dominant feature in the diffraction pattern. This contrasts sharply with the 1:1.56:2.7 ratio observed in the experimental material between the (100), (110), and (111) reflection peaks. When the experimental diffraction pattern is compared with the pattern derived from the model, the relative intensity is similar to that of materials containing side-chain BDCs. This is consistent with the thermal analysis of the sample, which contains more organic matter than expected from the experimental formulation of the metal-organic framework EMM-71 of Zr6O4(OH)4BDC4.

[0060] The presence of the second organic ligand was supported by thermal analysis of the prepared materials. Assuming the residual weight at 600 °C was pure ZrO2, the predicted weight of the fully hydrolyzed structure with the chemical formula Zr6O4(OH)8(H2O)4(BDC)4 (where all Zr sites are capped with water and hydroxyl groups without coordination to the BDC linker) could be estimated. These materials exhibited excessive organic weight loss, consistent with the presence of the side-chain organic ligand. Nitrogen adsorption revealed a relatively lower micropore volume than expected for materials with such a high degree of nodal defect.

[0061] To remove side-chain ligands and achieve pore volumes indicating defective structures, defective MOFs can be washed in a weakly alkaline solution. For example, sodium borate, weakly interacting anions (as opposed to phosphate or carbonate), and a moderately pH 9 buffer can be used to wash MOFs, and a significant decrease in peak intensity can be observed. To mitigate the destructive effects of borate solutions, we attempted washing procedures at lower temperatures and lower borate concentrations. In all cases, an increase in (100) reflectance relative to (111) reflectance was observed, indicating the loss of side-chain ligands. Less organic matter loss was observed in the thermal analysis of the samples. Gas adsorption measurements showed that when 0.25 M NaBO was used at temperatures of 100 °C, 60 °C, and 80 °C, respectively... x In solution, the adsorption capacity increases moderately. See Figure 12A Higher concentrations of the solution can reduce the specific surface area, which may be due to the degradation of the skeleton.

[0062] In addition to weakly interacting anions such as borate anions, we also tested the effectiveness of formate solutions in removing these side-chain ligands. Although borate solutions were expected to potentially lead to hydroxylated zirconium sites, formate could exchange with side-chain-suspended ligands and leave formate-terminated defect sites. For this purpose, samples washed with sodium formate under conditions somewhat similar to those for borate-washed samples were subjected to thermal analysis, consistent with samples primarily composed of formate-terminated groups. See [link to relevant documentation] Figure 10 Powder X-ray diffraction should show a characteristic increase in the reflectance intensity of (100) and (110) relative to (111), which we believe is due to the formation of a more open framework. Figure 11A REO domains without excess BDC ligands were observed. Figure 11B The results showed that one-third of the available REO domains were capped by an excess of BDC ligands. Figure 11C All available sites are shown when capped with an excess of BDC ligand.

[0063] Adsorption studies on materials washed with formate showed increases in measured micropore volume and specific surface area. However, these results represent an unoptimized washing procedure. Removal of side-chain ligands is accompanied by structural degradation under high temperature and high pH conditions. This washing procedure was performed using 0.5 M sodium formate at 60°C, 80°C, and 100°C for 30 minutes or 180 minutes to investigate the effects of washing temperature and time on the washing effect. Optimal washing conditions require a short contact time with sodium formate at 100°C. Figure 12BAs shown, the micropore volume increased by 10% to 20% from the minimum to the optimal washing conditions. In all cases, the relatively flat plateau region of 0.2–0.95 P / P0 indicates low textured porosity and large grain size. Indeed, SEM micrographs of the material obtained from this synthesis show large polycrystalline aggregates reminiscent of early unregulated MOF materials. See also Figure 13A , Figure 13B , Figure 13C and Figure 13D This is not necessarily due to the presence of the divalent modifier, as the control reaction exhibited the same particle morphology in the absence of the divalent modifier. It is more likely due to the relatively high synthesis concentration.

[0064] This invention provides a metal-organic framework comprising a plurality of tetravalent cations and terephthalic acid-type linkers crystallized in a simple cubic lattice and having a diameter of approximately 1100 μm. 2 / g~2700m 2 The specific surface area is approximately 0.45 cc / g to 1.1 cc / g, and the relative strength is equal to or greater than 0.35. In one aspect, the tetravalent cation is a tetravalent metal cation selected from Zr, Ti, Hf and / or Ce, for example Zr or a mixture of Zr and Hf. In one aspect, the terephthalic acid-type linker is selected from: 1,4-benzenedicarboxylate (BDC) or its derivatives such as 2-amino-1,4-benzenedicarboxylic acid (2-amino-1,4-benzenedicarboxylate), 1,2,4-benzenedicarboxylic acid (1,2,4-benzenedicarboxylate), 1,3,5-benzenedicarboxylic acid (pyromellitic acid) (1,3,5-benzenedicarboxylate), 1,2,4,5-benzenedicarboxylic acid (1,2,4,5-benzenedicarboxylate), 2-nitro-1,4-benzenedicarboxylic acid (2-nitro-1,4-benzenedicarboxylate), 2-chloro-1,4-benzenedicarboxylic acid (2-chloro-1,4-benzenedicarboxylate), 2-bromo-1,4-benzenedicarboxylic acid (2-bromo-1,4-benzenedicarboxylate), and mixtures thereof. In one aspect, the metal-organic framework further comprises about 0.0% to 10.0% by weight of divalent cations, such as divalent metal cations like Zn, Co, Sn and / or Cu.

[0065] More specifically, the metal-organic framework may comprise multiple zirconium cations and multiple BDC linkers in a simple cubic lattice, as well as approximately 0.0 wt% to 10.0 wt% of divalent cations. The metal-organic framework has a molecular weight of approximately 1100 μm as measured by nitrogen BET. 2 / g~2700m 2 The specific surface area per g, the porosity of approximately 0.45 cc / g to 1.1 cc / g, the relative strength equal to or greater than 0.35, and / or the peak width ratio less than 3.0.

[0066] In one aspect, the metal-organic framework may be composed of 20.4130, 14.4691, 11.8446 and The first five diffraction peaks with d spacing are used to characterize the structure, which contains simple cubic unit cells. In one aspect, the metal-organic framework has a peak width ratio of less than 3 (the half maximum peak width between the (110) and (111) reflections).

[0067] According to one embodiment of the present invention, the metal-organic framework is prepared by a method comprising the steps of: reacting a first metal source capable of generating a tetravalent metal cation in solution, a polyorganic carboxylic acid (i.e., a molecule capable of binding two sites, such as a linear dicarboxylic acid like 1,4-benzenedialic acid or a derivative thereof), a second metal source capable of generating a divalent cation in solution, and one or more monocarboxylic acid modifiers in a solvent to provide a reaction solution; and heating the reaction solution to provide a reaction mixture containing a metal-organic framework, the metal-organic framework being, for example, containing trace amounts (0 wt%) to about 10 wt% of a divalent cation and having a molecular weight of about 1100 m. 2 / g~2700m 2 Metal-organic framework with a specific surface area of ​​approximately 0.45 cc / g to 1.1 cc / g, a relative strength of 0.35 or greater, and / or a (110) / (111) peak width ratio of less than 3.

[0068] In another embodiment, the present invention relates to a method for preparing a metal-organic framework, the method comprising the steps of: reacting a first metal source capable of generating tetravalent metal cations (e.g., in the form of metal precursors, metal complexes, or metal oxides) in solution, a polybasic organic carboxylic acid capable of generating terephthalic acid-type linkers, a second metal source capable of generating divalent cations (e.g., in the form of metal precursors, metal complexes, or metal oxides) in solution, and one or more monocarboxylic acids in a solvent to provide a reaction solution; heating the reaction solution to a reaction temperature of at least 75°C to provide a reaction mixture; and separating the metal-organic framework material from the reaction mixture.

[0069] In one aspect, the first metal is selected from Zr, Ti, Hf, and / or Ce, for example, Zr or a combination of Zr and Hf. The first metal source can be in any suitable form, such as a metal precursor, a metal complex, or a metal oxide, for example, a metal chloride, oxychloride, nitrate, oxynitrate, or oxide.

[0070] In one aspect, the second metal is selected from Zn, Co, Sn, Cu, and mixtures thereof. The second metal source can be in any suitable form, such as a metal precursor, a metal complex, or a metal oxide, for example, a metal chloride, oxychloride, nitrate, oxynitrate, or oxide.

[0071] In one aspect, the polycarboxylic acid is selected from aromatic di, tri, or tetracarboxylic acids capable of producing terephthalic acid-type linkers. In another aspect, the polycarboxylic acid is functionalized, for example, by an alkyl, halogen, nitro, cyano, amino, sulfonyl, thio, isocyano, alkoxy, ether, ester, or carboxylic acid group. Suitable examples of polycarboxylic acids include 1,4-benzenediacarboxylic acid (terephthalic acid) or derivatives thereof, 2-amino-1,4-benzenediacarboxylic acid, 1,2,4-benzenetricarboxylic acid (triphenylcarboxylic acid), 1,3,5-benzenetricarboxylic acid (pyromellitic acid), 1,2,4,5-benzenetetracarboxylic acid, 2-nitro-1,4-benzenediacarboxylic acid, 2-chloro-1,4-benzenediacarboxylic acid, 2-bromo-1,4-benzenediacarboxylic acid, and mixtures thereof, with particularly suitable examples being terephthalic acid or pyromellitic acid.

[0072] In one respect, the monocarboxylic acid is selected from any monocarboxylic acid commonly used as a modifier in the synthesis of MOFs, especially FCU topological zirconium MOFs, such as formic acid, acetic acid, benzoic acid, difluoroacetic acid, or trifluoroacetic acid. In other respects, the concentration of the monocarboxylic acid is about 30% to 70% of the total solvent volume (the total solvent volume is calculated as the total amount of the monocarboxylic acid, organic solvent, and optionally water present in the reaction solution).

[0073] In one aspect, the solvent is selected from any organic solvent commonly used in the synthesis of MOFs, especially FCU topological zirconium MOFs, typically polar aprotic solvents such as dimethylformamide (DMF). Without wishing to be bound by theory, it is believed that the solvent, particularly DMF, can provide a unique coordination environment for the second metal (or divalent cation), which may play a role in its effectiveness in providing the metal-organic framework according to the invention.

[0074] In one respect, the molar ratio of tetravalent cation to linker (especially terephthalic acid type linker) is about 1.75:1 to about 1:1.75.

[0075] In one aspect, the molar ratio of divalent cation to tetravalent cation is about 0 to about 5, for example, up to 2 or up to 1, for example, up to 0.5 and / or at least 0.05 or at least 0.1, for example, at least 0.15.

[0076] In one aspect, the reaction solution also contains water at a concentration of approximately 0 to 5 mol per liter of total reaction volume.

[0077] In one aspect, the reaction solution also contains one or more of F, Cl, Br, or I ions, particularly Cl. These halide ions can be introduced via a first and / or second metal source. Suitable sources of such halide ions also include corresponding ammonium halides, HCl, HF, HBr, and HI. In one aspect, when using 35 mol% M:Zr with M source being MCl2 and Zr source being ZrCl4, halide ions can be present in any suitable amount, for example, up to a Cl:Zr molar ratio of 4.7:1 and a Cl:M ratio of 13:1. 2+ Mole ratio.

[0078] In one aspect, the reaction solution is heated to a reaction temperature of less than 200°C, especially less than 160°C or less than 150°C, more particularly less than 140°C, for example 80°C to 130°C, for example 90°C to 100°C. The metal-organic framework material can be separated from the reaction mixture by standard methods, such as centrifugation or filtration.

[0079] This method may also include washing the metal-organic framework material separated from the reaction mixture using any standard method. For example, the metal-organic framework material may be washed with solvents such as DMF, methanol, ethanol, acetone, and / or water to remove excess organic ligands. The metal-organic framework material may also be washed in a weakly alkaline solution, such as in a borate or formate solution like boron borate or boron formate, to remove side-chain ligands.

[0080] The reaction mixture comprises a metal-organic framework material, and the metal-organic framework material comprises a plurality of metal-organic frameworks. In one particular aspect, each of the plurality of metal-organic frameworks has a plurality of tetravalent cations and terephthalic acid-type linkers crystallized in a simple cubic lattice, having less than about 5.0 wt%, for example about 3.0 wt%, to about 5.0 wt% of divalent cations in the prepared material, and having a relative strength equal to or greater than 0.35.

[0081] In one particular aspect, the metal-organic framework prepared by the methods described herein can therefore contain multiple zirconium cations and BDC linkers in a simple cubic lattice, as well as less than about 5.0 wt%, for example, about 3.0 wt%, to about 5.0 wt%, of divalent cations in the prepared material. The relative strength of the zirconium-based metal-organic framework is equal to or greater than 0.35.

[0082] Furthermore, the present invention provides a method for regulating the defect structure or morphology of metal-organic frameworks, particularly MOFs crystallized in a simple cubic lattice, such as FCU-topological MOFs (e.g., FCU-topological zirconium MOFs, e.g., UiO-66), the method comprising the step of synthesizing the metal-organic framework in the presence of a second metal or a second metal cation. In one aspect, the metal-organic framework comprises: a first metal having a different valence state than the second metal or the second metal cation, particularly, the metal or the first metal being a tetravalent metal or a tetravalent metal cation (e.g., Zr, Ti, Hf, and / or Ce); and a second metal or a second metal cation, which is a divalent metal or a divalent metal cation (e.g., Zn, Co, Sn, and / or Cu). This method can be applied, for example, to metal-organic frameworks comprising multiple tetravalent cations, particularly multiple zirconium cations, and terephthalic acid-type linkers crystallized in a simple cubic lattice.

[0083] In one embodiment of various aspects of the invention, the metal-organic framework primarily has a REO topology, particularly a REO topology with FCU defects. For example, the metal-organic framework may correspond to UiO-66 with high or even complete defects (measured by relative strength reflecting the degree of defect), which may be referred to as a REO-UiO-66 family material. The highly defective / completely defective framework as disclosed in this application or manufactured by the methods of this application may be referred to as EMM-71.

[0084] In another specific embodiment of various aspects of the invention, the metal-organic framework has at least one of the following properties: at least about 1400 or at least about 1600 m. 2 / g and / or up to about 2400 or up to about 2200m 2 Specific surface area per g; porosity of at least about 0.55 cc / g and / or at most about 0.75 cc / g; relative intensity of at least 0.45 or at least 0.55 or at least 0.65, for example at least 0.75 or even at least 1.0; and / or peak width ratio of less than 2.9 or less than 2.8 or less than 2.7, for example less than 2.5, less than 2.0, less than 1.75 or even less than 1.5 or less than 1.25, for example as low as 1.2 or even lower.

[0085] In various aspects of this invention, cubic structure or cubic lattice type refers to cubic Bravais structure or cubic Bravais lattice type.

[0086] The various aspects of the invention will be described in more detail through specific embodiments. The following embodiments are provided for illustrative purposes and are not intended to limit the invention in any way. Those skilled in the art will readily recognize that various parameters can be changed or modified to produce substantially the same results. The following non-limiting embodiments are provided to illustrate the invention.

[0087] Example

[0088] In these embodiments, X-ray diffraction (XRD) patterns of the material were recorded in continuous mode using Cu Kα radiation, a Bragg Bentano geometry, and a Lynxeye detector in the 2θ range of 2 to 60° on an X-ray powder diffractometer (Bruker D8 Envdevor instrument). Interplanar spacing and d-spacing were calculated in angstroms. Intensities were uncorrected for Lorentz and polarization effects. The positions of the 2θ diffraction peaks and the relative peak area intensities I / I(o) of the spectral lines were determined using a third-order polynomial background fitting algorithm with the MDI Jade peak fitting algorithm, where Io is the intensity of the strongest spectral line against the background. It should be understood that diffraction data listed as single lines may consist of multiple overlapping lines, which may appear as resolved or partially resolved lines under specific conditions such as differences in crystallographic variations. Typically, crystallographic variations may include small changes in cell parameters and / or crystal symmetry, but not changes in framework connectivity. These subtle effects, including variations in relative intensity, can also arise from differences in cation content, framework composition, the nature and extent of pore filling, crystal size and shape, preferred orientation, and thermal and / or hydrothermal history.

[0089] Relative intensities were measured using the method described by GC et al., *Defect Engineering: Tuning the Porosity and Composition of the Metal-Organic Framework UiO-66 via modulated Synthesis*, Chem. Mater., 28, 11, 3749-3761, 2016. Relative intensities characterize the extent of defects in the framework, particularly nodal defects. As described by Shearer et al., the relative intensities of broad peaks (i.e., 3°2θ–7°2θ) are a quantitative description of the concentration of missing cluster defects in the framework, such as the UiO-66 framework. Relative intensities were calculated by dividing the integrated intensity of the broad peak (approximately 5°2θ, e.g., 2–7°2θ, corresponding to the total integrated intensity of the (100) and (110) peaks in this invention) by the average of the intensities of the (111), (200), and (600) peaks at approximately 7.4, 8.5, and 25.8°2θ, respectively.

[0090]

[0091] The peak width ratio is the ratio between the calculated half-maximum peak widths (calculated by the MDI Jade peak fitting algorithm) of the (110) peak and the (111) peak produced at ~6°2θ and 7.4°2θ.

[0092] Scanning electron microscope (SEM) images of the directly synthesized material were obtained on a Hitachi 4800 scanning electron microscope.

[0093] Specific surface area of ​​the material (S) BET The nitrogen adsorption-desorption at liquid nitrogen temperature was determined by the BET method as described by S. Brunauer, PHEmmett and E. Teller, J. Am. Chem. Soc., 1938, 60, 309, which are incorporated herein by reference.

[0094] The porosity (or micropore volume) of a material can be determined using methods known in the relevant field. For example, the porosity of a material can be measured by the physical adsorption of nitrogen, and the data can be analyzed using the t-plotting method described in Lippens, BC et al., “Studies on pore system in catalysts: V. The t method”, J. Catal., 4, 319 (1965), which describes the micropore volume method and is incorporated herein by reference.

[0095] Thermogravimetric analysis (TGA) was performed on the material by heating it in air from room temperature to 850°C.

[0096] Example 1: Inducing REO defects in the structure of EMM-71 using SnCl2.

[0097] Terephthalic acid, zirconyl chloride octahydrate, tin dichloride dehydrate, dimethylformamide, and acetic acid (as shown in Table 1) were placed in 20 cubic centimeter (“cc”) vials and heated for 16–20 hours with magnetic stirring. The reactants used for eight (8) samples are as follows.

[0098] Table 1

[0099] Reaction materials

[0100]

[0101] *Molar ratio, where M 总 =Zr+Sn and L=BDC.

[0102] After the reaction, the sample was separated by centrifugation or filtration, and excess organic ligands were washed from the bulk using excess dimethylformamide and a high-boiling-point solvent exchanged with acetone. The sample was then dried in air at 130°C to 150°C. X-ray diffraction patterns of the sample were obtained. Results showed that peaks associated with missing node defects were observed when SnCl2 and a high acetic acid ratio (HOAc:BDC > 25) were combined.

[0103] Figure 3 The powder X-ray diffraction results for the samples (prepared in the presence of tin chloride) are shown in Table 1. Although the effect of tin is slightly milder compared to the degree of defects produced by other methods such as using HCl or water as a modifier, a larger pore volume can be achieved by this technique.

[0104] Figure 4 Thermogravimetric analysis (“TGA”) of the samples (synthesized in the presence of SnCl2) is provided in Table 1. The TGA indicates that samples 2, 3, and 6, i.e., those with the largest missing segment defects, have greater initial solvent losses than the other samples in the series. Figure 4 As shown, the temperature range of 0℃ to 120℃ represents the solvent adsorbed in the porous structure, and a larger loss corresponds to a larger pore volume. The second weight loss at 150℃ to 200℃ is related to the dehydration of the structural nodes.

[0105] More specifically, Figure 4 The table below shows the weight percentage of each sample at two different signal values ​​at a temperature of °C, as detailed in Table 2. For example, sample 1 has the following characteristics: Figure 4 The signal values ​​1a and 1b are shown.

[0106] Table 2 shows the weight percentage and temperature at the two signal values.

[0107]

[0108] High pore volumes leading to increased solvent weight loss were also observed in the nitrogen adsorption isotherms of samples 1 and 2. Figure 5A and Figure 5B The figures show the nitrogen adsorption isotherms for samples 1 and 2 in Table 1, respectively. As shown in the figure, the initial nitrogen adsorption amounts of the two samples are similar (10... -5 ~10 -3 P / P0). This superficially corresponds to the filling of defect-free regions. However, above these pressures, we observed that sample 2 exhibits a second rising characteristic associated with the filling of defective regions, resulting in a relatively high nitrogen adsorption capacity of approximately 400 cm⁻¹ in the Sn sample, even with only a small number of REO defects. 3 / g. This corresponds to 1415 m. 2The specific surface area was 0.494 cc / g and the micropore volume was 0.494 cc / g (measured by t-plotting).

[0109] Example 2: Using Co 2+ or Zn 2+ Inducing REO defects in the EMM-71 structure

[0110] To attempt to evaluate whether this effect extends to other divalent metals, reactions similar to reactions 2 and 3 were conducted using Mg, Ca, Li, Ni, Cu, Zn, and Co. Figure 6 X-ray diffraction patterns of Zr-BDC synthesized in the presence of several metal cations are shown. In the cases of various metals, equimolar substitutions of tin chloride were performed, as shown in Experiment 2 or Experiment 3. See also Figure 6 No effect was observed for magnesium, lithium, and nickel. Under these conditions, copper chloride produced a moderate number of nodal defects, but surprisingly, zinc and cobalt were very effective at producing REO defects at high concentrations, with large domain sizes (determined by Shearer broadening) similar to the primary grain size.

[0111] Defects created using this method are somewhat sensitive to the concentration of acetic acid in the solution. Some experiments using cobalt ions show that, under otherwise identical conditions, the defect rate begins to decrease as the DMF:acetic acid ratio increases.

[0112] Table 3

[0113] DMF: Increased acetic acid ratio

[0114]

[0115] Table 4 DMF: Acetic Acid Ratio Constant

[0116]

[0117] Figure 7A Powder X-ray diffraction patterns of Zr-MOF synthesized in reactions 1, 2, and 3 as shown in Table 3 are displayed. Furthermore, Figure 7B The powder X-ray diffraction patterns of the Zr-MOFs synthesized in reactions 1, 2, and 3 shown in Table 4 are displayed. As shown, decreasing the acetic acid solution concentration leads to a loss of highly ordered defects, regardless of the HOAc:reagent ratio, because maintaining a constant solvent composition (in this example, the HOAc / DMF composition) will preserve the defects. This highlights the importance of solvent composition.

[0118] In addition to sensitivity to solvent composition, the effect of chloride ion presence was determined through experiments using nitrate-based starting materials. Table 5 lists the following reactants.

[0119] Table 5 Nitrate Starting Materials

[0120]

[0121] *Molar ratio, where M 2+ =Co and / or Zn, and L = BDC.

[0122] like Figure 8 As shown, the powder X-ray diffraction patterns of the samples in Table 5 synthesized from nitrates highlight the presence of Cl in the absence of Cl. - In the case of ions, large defect domains do not form with cobalt or zinc cations. Reactions 5 and 6 show that when HCl is introduced as a source for these ions, the defect structure returns (see...). Figure 8 (The two bottom curves). This corresponds to relative intensities of 2.3 and 1.7, and peak ratios of 1.27 and 1.73, respectively.

[0123] EMM-71 was prepared on a large scale using cobalt chloride according to the method of Example 2. Table 7 shows the conditions and the resulting relative intensities and peak ratios. Specific surface area and pore volume were measured after washing the samples with sodium formate. Untreated MOF was suspended in a 0.25–0.5 M aqueous sodium formate solution to form a 10 wt% slurry (10 parts MOF and 90 parts sodium formate solution). The solution was then heated to 80–100 °C for 30–120 minutes. The MOF was then separated and washed with water or formic acid solution. The samples were exchanged with acetone and then activated under dynamic vacuum at 80–150 °C for 10–12 hours.

[0124]

[0125] Example 3: Synthesis of EMM-71 using CuCl2

[0126] Add 0.449 g terephthalic acid, 512 mg ZrCl4, and 130 mg copper chloride dihydrate to a 20 mL vial, along with 5 mL dimethylformamide, 5 mL glacial acetic acid, and 315 μL water. Heat the reaction to 90 °C and continue for 12–24 hours. Filter the solution and wash with dimethylformamide and acetone. Figure 14 The powder X-ray diffraction pattern of EMM-71 manufactured in this embodiment is shown. Figure 14 The powder XRD pattern shown has a relative intensity of 3.47 and a peak ratio of 1.17.

[0127] Example 4: Synthesis of EMM-71 using ZnO

[0128] 78.98 g of BDC and 90 g of ZrCl4 were added to a 1 L round-bottom flask. 16 g of zinc oxide was added. 439 mL of acetic acid was added, followed by 439 mL of DMF. Finally, 22.5 mL of water was added. The reaction was then stirred at 80 °C for 12–24 hours. The MOF product was filtered, washed with DMF, then with acetone, and dried at 90–130 °C. The material was then optionally washed with sodium formate in a manner similar to that used for the material derived from Example 2. The sample yielded a material with a relative strength of 2.0 and a peak ratio of 1.3. The formate-washed sample showed a value of 2003 m in the t-plot. 2 The BET specific surface area is 0.723 cc / g and the pore volume is 0.723 cc / g.

[0129] Example 5: Synthesis of mixed Zr / Hf EMM-71

[0130] Add 441 mg terephthalic acid, 393.6 mg zirconium oxychloride hydrate, and 125 mg hafnium oxychloride hydrate. Add 5 mL dimethylformamide and 5 mL acetic acid, and stir the reaction at 90 °C for 12–24 hours. Separate the solid and wash with additional dimethylformamide, then wash with acetone. Figure 15 The powder X-ray diffraction pattern of EMM-71 manufactured in this embodiment is shown. Figure 16 The powder X-ray diffraction patterns of Hf-Zr EMM-71 prepared under conditions with different molar percentages of Hf in the total Hf+Zr content are shown in Table 8. Figure 16 The conditions of the material and the calculated relative strength and peak ratio.

[0131] Table 8

[0132] Mixed Zr / Hf EMM-71

[0133]

[0134] Example 6: Time Test for EMM-71 Formation

[0135] 3.59 g of terephthalic acid, 5.59 g of zirconium oxychloride hydrate, and 852 mg of anhydrous cobalt chloride were added to 50 mL of dimethylformamide and 50 mL of acetic acid, and the mixture was heated to 90 °C. Samples were taken at 45, 80, 120, 195, and 255 minutes. The samples were filtered and washed with acetone. Figure 17 The powder X-ray diffraction patterns of EMM-71 aliquots were taken at 45, 80, 120, 195, and 255 minutes (from bottom to top). In these samples, the initial relative intensity ranged from 1.55, decreasing to 1.23 at the end of 255 minutes, while the peak ratio varied between 1.08 and 1.26 during the 4-hour run.

[0136] Example 7: Synthesis of EMM-71 using CoCl2 and chlorine-BDC

[0137] In a 10 mL vial, 0.25 g of 2-chlorophthalic acid, 0.203 g of ZrCl4, 0.035 g of CoCl2, 2 mL of dimethylformamide (DMF), 3 mL of acetic acid, and 125 μl of deionized (DI) water were mixed together. The resulting mixture was heated at 90 °C with stirring for 16 hours. After cooling to room temperature, the resulting solid was filtered, washed with DMF, and then washed with acetone. Figure 18 The powder X-ray diffraction pattern of EMM-71 (relative intensity 0.81) manufactured in this embodiment is shown.

[0138] Example 8: Synthesis of EMM-71 using CoCl2 and chlorine-BDC

[0139] In a 10 mL vial, 0.25 g of 2-chlorophthalic acid, 0.203 g of ZrCl4, 0.035 g of CoCl2, 2 mL of dimethylformamide (DMF), 3 mL of acetic acid, 20 μl of concentrated HCl, and 63 μl of deionized water were mixed together. The resulting mixture was heated at 90 °C with stirring for 16 hours. After cooling to room temperature, the resulting solid was filtered, washed with DMF, and then washed with acetone. The powder X-ray diffraction pattern conformed to the characteristics of EMM-71, with a relative intensity of 0.87.

[0140] Example 9: Synthesis of EMM-71 using ZnO and chlorine-BDC

[0141] In a 20 mL vial, 0.75 g of 2-chlorophthalic acid, 0.609 g of ZrCl4, 0.075 g of ZnO, 6 mL of dimethylformamide (DMF), 9 mL of acetic acid, and 93 μl of deionized water were mixed together. The resulting mixture was heated at 90 °C with stirring for 16 hours. After cooling to room temperature, the resulting solid was filtered, washed with DMF, and then washed with acetone. The powder X-ray diffraction pattern conformed to the characteristics of EMM-71, with a relative intensity of 0.95.

[0142] Example 10: Synthesis of EMM-71 using CoCl2 and bromo-BDC

[0143] In a 10 mL vial, 0.3 g of 2-bromophthalic acid, 0.208 g of ZrOCl₂·H₂O, 0.035 g of CoCl₂, 2 mL of dimethylformamide (DMF), and 3 mL of acetic acid were mixed together. The resulting mixture was heated at 90 °C with stirring for 16 hours. After cooling to room temperature, the resulting solid was filtered, washed with DMF, and then washed with acetone. The powder X-ray diffraction pattern conformed to the characteristics of EMM-71, with a relative intensity of 1.01.

[0144] Alternatively or concurrently, the present invention relates to:

[0145] Implementation Scheme 1. A metal-organic framework comprising a plurality of tetravalent cations and terephthalic acid-type linkers crystallized in a simple cubic lattice, wherein the metal-organic framework has a density of approximately 1100 μm. 2 / g~2700m 2 Specific surface area per g, porosity of approximately 0.45 cc / g to 1.1 cc / g, and relative strength equal to or greater than 0.35.

[0146] Implementation Scheme 2. A metal-organic framework material, optionally according to Implementation Scheme 1, characterized in that at 20.4130, 14.4691, 11.8446 and The first five diffraction peaks have a spacing of d and contain simple cubic unit cells.

[0147] Implementation Scheme 3. The metal-organic framework according to Implementation Scheme 1 or 2, wherein the tetravalent cation is selected from Zr, Ti, Hf and / or Ce, particularly from Zr and / or Hf.

[0148] Implementation Scheme 4. The metal-organic framework according to any one of Implementation Schemes 1 to 3, wherein the terephthalic acid type linker is selected from 1,4-benzenedicarboxyl (BDC), 2-amino-1,4-benzenedicarboxyl, 1,2,4-benzenetricarboxyl, 1,2,4,5-benzenetetracarboxyl, 2-nitro-1,4-benzenedicarboxyl, 2-chloro-1,4-benzenedicarboxyl, 2-bromo-1,4-benzenedicarboxyl, and mixtures thereof.

[0149] Implementation Scheme 5. The metal-organic framework according to any one of the foregoing embodiments further comprises about 0.0% to 10.0% by weight of divalent cations.

[0150] Implementation Scheme 6. The metal-organic framework according to Implementation Scheme 4, wherein the divalent cation is selected from Zn, Co, Sn and / or Cu.

[0151] Implementation Scheme 7. The metal-organic framework according to any one of the foregoing implementation schemes, having at least one of the following properties: approximately 1400m 2 / g~2400m 2 / g, preferably about 1600m 2 / g~2200m 2 Specific surface area per g; porosity of about 0.55 cc / g to 0.75 cc / g; and / or relative strength of about 0.45 to 2.9, preferably about 0.55 to 0.65 to about 2.5 or 2.0.

[0152] Implementation Scheme 8. The metal-organic framework according to any one of the preceding implementation schemes, wherein the metal-organic framework has a peak width ratio of less than 3.0, preferably less than 2.5, more preferably less than 2, for example less than 1.50.

[0153] Implementation Scheme 9. The metal-organic framework according to any one of the foregoing embodiments, comprising a plurality of zirconium cations and a plurality of BDC linkers.

[0154] Implementation Scheme 10. A metal-organic framework comprising a plurality of zirconium cations and BDC linkers in a simple cubic lattice and less than about 5.0% by weight of divalent cations, wherein the zirconium-based metal-organic framework has a relative intensity equal to or greater than 0.35 and a peak width ratio less than 3.0.

[0155] Implementation Scheme 11. The metal-organic framework according to any one of the preceding embodiments, which is prepared by a method comprising the steps of: reacting a first metal source capable of generating tetravalent metal cations in solution, a linear dicarboxylic acid, a second metal source capable of generating divalent cations in solution and one or more monocarboxylic acid modifiers in a solvent to provide a reaction solution, and heating the reaction solution to provide a reaction mixture comprising the metal-organic framework.

[0156] Implementation Scheme 12. The metal-organic framework material according to any one of the preceding implementation schemes, wherein the metal-organic framework material has a half-maximum peak width ratio of less than 3 for the (110) to (111) reflections.

[0157] Implementation Scheme 13. A method for preparing a metal-organic framework, particularly the metal-organic framework of any of the preceding embodiments, comprising the steps of: (a) reacting a first metal source in the form of a metal precursor, a metal complex, or a metal oxide, a polyorganocarboxylic acid, a second metal source in the form of a metal precursor, a metal complex, or a metal oxide, and one or more monocarboxylic acids in a solvent to provide a reaction solution; (b) heating the reaction solution to a reaction temperature of at least 75°C to provide a reaction mixture, wherein the reaction mixture comprises a metal-organic framework material; and (c) separating the metal-organic framework material from the reaction mixture.

[0158] Implementation Scheme 14. The method according to Implementation Scheme 13, wherein the first metal source can generate a tetravalent metal cation in solution, and in particular, wherein the first metal is selected from zirconium, hafnium, titanium, cerium or mixtures thereof, such as Zr or a mixture of Zr and Hf.

[0159] Implementation Scheme 15. The method according to Implementation Scheme 13 or 14, wherein the second metal source can generate a divalent metal cation in solution, and in particular, wherein the second metal is selected from Zn, Co, Sn, Cu or mixtures thereof.

[0160] Implementation Scheme 16. The method according to any one of Implementation Schemes 13 to 15, wherein the polycarboxylic acid can produce a terephthalic acid type linker.

[0161] Implementation Scheme 17. The method according to any one of Implementation Schemes 13 to 16, wherein the polycarboxylic acid is selected from aromatic di, tri, or tetracarboxylic acids.

[0162] Implementation Scheme 18. The method according to any one of Implementation Schemes 13 to 17, wherein the polycarboxylic acid is functionalized by an alkyl, halogen, nitro, cyano, amino, sulfonyl, thio, isocyano, alkoxy, ether, ester or carboxylic acid group.

[0163] Implementation Scheme 19. The method according to any one of Implementation Schemes 13 to 18, wherein the polycarboxylic acid is selected from: 1,4-benzenediacarboxylic acid (terephthalic acid), 2-amino-1,4-benzenediacarboxylic acid, 1,2,4-benzenetricarboxylic acid (triphenylcarboxylic acid), 1,3,5-benzenetricarboxylic acid (pyromellitic acid), 1,2,4,5-benzenetetracarboxylic acid, 2-nitro-1,4-benzenediacarboxylic acid, 2-chloro-1,4-benzenediacarboxylic acid, 2-bromo-1,4-benzenediacarboxylic acid, and mixtures thereof; particularly selected from terephthalic acid and pyromellitic acid.

[0164] Implementation Scheme 20. The method according to any one of Implementation Schemes 13 to 19, wherein the monocarboxylic acid is selected from formic acid, acetic acid, benzoic acid, difluoroacetic acid, or trifluoroacetic acid.

[0165] Implementation Scheme 21. The method according to any one of Implementation Schemes 13 to 20, wherein the solvent is a polar aprotic solvent, such as dimethylformamide (DMF).

[0166] Implementation Scheme 22. The method according to any one of Implementation Schemes 13 to 21, wherein the concentration of the monocarboxylic acid is about 30% to 70% of the total volume of the solvent (calculated as the total volume of the monocarboxylic acid, organic solvent and optional water present in the reaction solution).

[0167] Implementation Scheme 23. The method according to any one of Implementation Schemes 13 to 22, wherein the molar ratio of the tetravalent cation to the linker, particularly the terephthalic acid type linker, is about 1.75:1 to about 1:1.75.

[0168] Implementation Scheme 24. The method according to any one of Implementation Schemes 13 to 23, wherein the molar ratio of the divalent cation and the tetravalent cation is about 0 to about 5, particularly 0 or at least 0.1 or at least 0.15 to 2 or at most 1 or at most 0.5.

[0169] Implementation Scheme 25. The method according to any one of Implementation Schemes 13 to 24, wherein the reaction solution further comprises water at a concentration of about 0 to 5 mol per liter of total reaction volume.

[0170] Implementation Scheme 26. The method according to any one of Implementation Schemes 13 to 25, wherein the reaction solution further comprises one or more of F, Cl, Br or I ions, particularly Cl.

[0171] Implementation Scheme 27. The method according to any one of Implementation Schemes 13 to 26, wherein the metal-organic framework material comprises a plurality of metal-organic frameworks, each of the plurality of metal-organic frameworks having a plurality of tetravalent cations and terephthalic acid type linkers crystallized in a simple cubic lattice, wherein the metal-organic framework has less than about 5.0% by weight of divalent cations and a relative strength equal to or greater than 0.35.

[0172] Implementation Scheme 28. A method for regulating the defect structure or morphology of a metal-organic framework, the method comprising the step of synthesizing the metal-organic framework in the presence of a second metal or a second metal cation.

[0173] Implementation Scheme 29. The method according to Implementation Scheme 28, wherein the metal-organic framework comprises a first metal having a different valence state than the second metal or a second metal cation.

[0174] Implementation Scheme 30. The method according to Implementation Scheme 28 or 29, wherein the metal or first metal is a tetravalent metal or a tetravalent metal cation, particularly selected from Zr, Ti, Hf, Ce or mixtures thereof, more particularly selected from Zr or mixtures of Zr and Hf.

[0175] Implementation Scheme 31. The method according to any one of Implementation Schemes 28 to 30, wherein the second metal or second metal cation is a divalent metal or divalent metal cation, particularly selected from Zn, Co, Sn, Cu or mixtures thereof.

[0176] Implementation Scheme 32. The metal-organic framework or method according to any one of the preceding embodiments, wherein the metal-organic framework comprises a plurality of tetravalent cations, particularly a plurality of zirconium cations, and terephthalic acid type linkers crystallized in a simple cubic lattice.

[0177] Implementation Scheme 33. The metal-organic framework or method according to any one of the foregoing embodiments, wherein the metal-organic framework primarily has a REO topology, particularly a REO topology with FCU defects.

[0178] Implementation Scheme 34. The metal-organic framework or method according to any one of the foregoing embodiments, wherein the metal-organic framework is REO-UiO-66 or EMM-71.

[0179] Taking into account experimental errors and biases, all numerical values ​​in the specific embodiments and claims may be modified with “about” or “approximately” relative to the indicated values.

[0180] For those skilled in the art, many changes, variations and modifications will be apparent from the above description without departing from the spirit or scope of the invention, and when lower and upper limits of values ​​are listed herein, a range from any lower limit to any upper limit is considered.

[0181] When lower and upper limits for numerical values ​​are listed herein, a range from any lower limit to any upper limit is considered. Although the invention has been described with reference to specific aspects, it is not limited thereto. Suitable variations / variations of operation under specific conditions will be apparent to those skilled in the art. Therefore, the claims should be construed as covering all such variations / variations that fall within the true spirit / scope of the invention.

Claims

1. A metal-organic framework comprising a plurality of tetravalent cations and terephthalic acid-type linkers crystallized in a simple cubic lattice, wherein the metal-organic framework has a 1400 μm 2 / g~2700 m 2 The specific surface area / g, the porosity of 0.45 cc / g to 1.1 cc / g, and the relative intensity equal to or greater than 0.45, wherein the relative intensity is calculated by dividing the integrated intensity of the 2 to 7°2θ broad peaks corresponding to the total integrated intensity of the (100) and (110) peaks by the average of the intensities of the (111), (200), and (600) peaks corresponding to approximately 7.4, 8.5, and 25.8°2θ, respectively, and wherein the tetravalent cation is selected from Zr or a mixture of Zr and Hf.

2. The metal-organic framework according to claim 1, wherein the terephthalic acid-type linker is selected from 1,4-benzenedicarboxyl (BDC) or derivatives of 1,4-benzenedicarboxyl, 2-amino-1,4-benzenedicarboxyl, 1,2,4-benzenetricarboxyl, 1,2,4,5-benzenetetracarboxyl, 2-nitro-1,4-benzenedicarboxyl, 2-chloro-1,4-benzenedicarboxyl, 2-bromo-1,4-benzenedicarboxyl, and mixtures thereof.

3. The metal-organic framework according to claim 1, wherein the metal-organic framework further comprises 3.0% to 10.0% by weight of a divalent cation, wherein the divalent cation is selected from Zn, Co, Sn and / or Cu.

4. The metal-organic framework according to claim 1, wherein the metal-organic framework comprises a plurality of zirconium cations and a plurality of BDC linkers.

5. The metal-organic framework according to claim 1, wherein the metal-organic framework comprises a plurality of zirconium cations and BDC linkers in a simple cubic lattice and less than 5.0% by weight of divalent cations, wherein the zirconium-based metal-organic framework has a peak width ratio of less than 3.0, the peak width ratio being the ratio between the half maximum peak widths of the (110) peak and the (111) peak generated at approximately 6°2θ and 7.4°2θ, respectively.

6. The metal-organic framework material according to claim 1, characterized in that... It has the first four X-ray diffraction peaks with d-spacing at 20.4130, 14.4691, 11.8446 and 10.2594 Å ± 5% and contains simple cubic unit cells.

7. The metal-organic framework material according to claim 1, wherein the metal-organic framework material has a peak width ratio of less than 3, the peak width ratio being the ratio between the half maximum peak widths of the (110) peak and the (111) peak generated at approximately 6°2θ and 7.4°2θ, respectively.

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