Metal organic structure

Abstract

The purpose of the present invention is to provide an MOF that easily adsorbs a target substance even when the relative pressure is low. The present invention is a metal-organic structure comprising a specific organic ligand and a specific metal ion, in which the ratio (maximum pore diameter L / minimum pore diameter S) of the maximum pore diameter L to the minimum pore diameter S as determined by steps (a1) to (a3) is 1.0-2.0, and the decomposition initiation temperature exceeds 200 DEG C. (a1) The crystal structure determined by X-ray crystal structure analysis is represented by a space filling model, and the presence or absence of the through-hole is observed under predetermined conditions to specify a through-hole (Pmax) in which the diameter of the inscribed circle is the largest. (a2) The maximum length of the inner diameter of the through-hole (Pmax) is found in a prescribed cross-section of the through-hole (Pmax), and the maximum diameter (L) of the through-hole (Pmax) is specified. And (a3) specifying the minimum aperture (S) within the cross section in which the maximum aperture (L) has been specified.

Description

Technical Field

[0001] The present invention relates to a metal-organic structure. Background Art

[0002] Metal-organic frameworks (MOFs), also known as porous coordination polymers, are materials that form porous structures through coordination bonds between metal ions and organic ligands, and have long been expected to be used for gas adsorption / desorption or as catalysts.

[0003] For example, Patent Document 1 discloses a metal-organic structure comprising metal ions, a first ligand, a second ligand, and an optional third ligand, wherein the metal ions are aluminum ions, the first and second ligands are organic compound ions composed of a heterocycle having two carboxyl groups, the angle formed by the heteroatom and the carboxyl group satisfies a specified condition, the third ligand is an organic compound ion having two carboxyl groups, and the proportions of the first to third ligands are within a specified range.

[0004] Prior Art Documents

[0005] Patent Documents

[0006] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2020-176101 Summary of the Invention

[0007] Problems to be Solved by the Invention

[0008] Metal-organic frameworks (hereinafter sometimes referred to as MOFs) are required to easily absorb moisture even in an environment with a low relative pressure: P / P0 (where P is the water vapor pressure and P0 is the saturated water vapor pressure), depending on the application.

[0009] Accordingly, an object of the present invention is to provide an MOF that easily adsorbs water even in an environment with a low relative pressure.

[0010] Means for Solving the Problems

[0011] The present invention for achieving the above problems is as follows.

[0012] [1] A metal-organic structure composed of an organic ligand and metal ions,

[0013] The above organic ligand contains R(COO - ) nThe represented organic ligand, where R is at least one of an unsaturated straight-chain hydrocarbon group, an aromatic hydrocarbon group, and a hydrocarbon group having an aromatic ring containing an oxygen atom, and it is a group that can have a functional group X of -OH or -S-S-, n is 2 or more and 3 or less,

[0014] The above metal ion is an ion of at least one metal selected from the group consisting of Al, Ga, In, Ti, V, Cr, Mn, Fe, Co, Cu, Zr, and Hf,

[0015] For the above metal-organic structure, the ratio of the maximum pore diameter L to the minimum pore diameter S (maximum pore diameter L / minimum pore diameter S) determined by the following steps (a1) to (a3) is 1.0 to 2.0,

[0016] The decomposition start temperature of the above metal-organic structure exceeds 200 °C.

[0017] (a1) Represent the crystal structure determined by X-ray crystal structure analysis in a space-filling model, representing it without missing the outer periphery of the through-hole, observing the presence or absence of the through-hole from all directions, and specifying the through-hole P with the largest inscribed circle diameter max .

[0018] (a2) In each of the cross-sections ab, cross-section bc, and cross-section ca of the above through-hole P max , find the maximum length of the inner diameter of the through-hole P cut by a line orthogonal to the central axis of the through-hole P max , and take the largest of the maximum lengths of the cross-sections ab, cross-section bc, and cross-section ca as the maximum pore diameter L of the through-hole P max . max Here, the so-called cross-section ab is the cut surface of the through-hole P in the plane parallel to the a-b plane of the unit cell, and it is a plane cut in a state where the through-hole P

[0019] passes through. In the case where there are multiple cross-sections that can cut the through-hole P in a state where it passes through, the cross-section with the largest overlap with the through-hole P max is called the cross-section ab. Moreover, in the specification of the above cross-section ab, the cross-section obtained by replacing the cross-section ab with the cross-section bc and replacing the a-b plane with the b-c plane is the cross-section bc, and the cross-section obtained by replacing the cross-section ab with the cross-section ca and replacing the a-b plane with the c-a plane is the cross-section ca. max max max

[0020] (a3) In the cross-section where the above maximum pore diameter L is determined, the through-hole P cut by a line orthogonal to the central axis of the through-hole P max , max ​​​The minimum length within the inner diameter is defined as the minimum pore diameter S.

[0021] [2] The metal-organic structure according to [1], wherein, when the crystal structure of the metal-organic structure determined by X-ray crystal structure analysis is represented by a space-filling model, the observed through-holes do not cross other through-holes.

[0022] Advantages of the Invention

[0023] According to the present invention, it is possible to provide a MOF that can adsorb a sufficient amount of water even in an environment with a relatively low relative pressure. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is an example of observing the crystal structure of a MOF represented by a space-filling model from one direction.

[0025] Figure 2 is an example of observing the crystal structure of a MOF represented by a space-filling model from another direction.

[0026] Figure 3 is an example of observing the crystal structure of a MOF represented by a space-filling model from yet another direction.

[0027] Figure 4 is a diagram showing the maximum pore diameter L and the minimum pore diameter S of the through-hole P max DETAILED DESCRIPTION OF THE INVENTION

[0028] The MOF of the present invention is composed of an organic ligand and metal ions, and the ratio of the maximum pore diameter L to the minimum pore diameter S (maximum pore diameter L / minimum pore diameter S) determined by a specified procedure is 1.0 to 2.0, and the decomposition start temperature exceeds 200 °C.

[0029] 1. Ratio of the maximum pore diameter L to the minimum pore diameter S (maximum pore diameter L / minimum pore diameter S)

[0030] In the MOF of the present invention, the maximum pore diameter L / minimum pore diameter S is 1.0 to 2.0. If the maximum pore diameter L / minimum pore diameter S is within the above range, the pores have a shape with few bends, so water can be adsorbed well even under a relatively low relative pressure. The maximum pore diameter L / minimum pore diameter S is preferably 1.03 or more, more preferably 1.05 or more, further preferably 1.10 or more. In addition, it is preferably 1.6 or less, more preferably 1.5 or less, and further preferably 1.4 or less. In addition, the maximum pore diameter L / minimum pore diameter S can also be 1.20 or more and 1.50 or less.

[0031] The maximum pore diameter L / minimum pore diameter S is determined by the following steps (a1) to (a3).

[0032] (a1) Represent the crystal structure determined by X-ray crystal structure analysis using a space-filling model, representing the outer periphery of the through-hole without omission, observing the presence or absence of the through-hole from all directions, and specifying the through-hole P with the largest inscribed circle diameter. max .

[0033] Similar to the measurement of the above void fraction, if X-ray crystal structure analysis is performed by XRD measurement, a cif file is obtained, and the cif file is read into Mercury as described above, a single space-filling model (crystal structure) can be obtained.

[0034] After obtaining the space-filling model of the crystal structure, represent the outer periphery of the through-hole without omission, rotate the crystal structure, and observe the presence or absence of the through-hole from all directions. Figures 1 to 3 Represent the case when the obtained crystal structure is rotated and the through-hole is observed from a specified direction. Figure 3 In, the inscribed circle 11 of the through-hole observed from the Figure 3 direction shown in is shown. Such inscribed circles are specified from all the through-holes observed from each direction, and the through-hole P with the largest inscribed circle diameter among all the observed through-holes is specified. max .

[0035] In step (a1), in order to observe all the observed through-holes without omission of the outer periphery, first observe with one unit cell. In the case of a through-hole with an omitted outer periphery, it is only necessary to observe a region 2×2×2 times the unit cell as long as it is displayed.

[0036] (a2) Next, observe the through-hole P max with the following specific cross-sections ab, cross-section bc, and cross-section ca.

[0037] The above cross-section ab is a cut surface of the through-hole P in a plane parallel to the a-b plane of the unit cell, and is a surface cut in a state where the through-hole P max penetrates. There may be multiple planes parallel to the a-b plane of the unit cell, and there may be a cross-section that can be cut in a state where the through-hole P max penetrates. In the case of multiple cross-sections, the cross-section with the largest overlap with the through-hole P max is called cross-section ab. max

[0038] Cross-section bc is a cross-section obtained by replacing cross-section ab with cross-section bc and replacing the a-b plane with the b-c plane in the above specification of cross-section ab.

[0039] In addition, cross-section ca is a cross-section obtained by replacing cross-section ab with cross-section ca and replacing the a-b plane with the c-a plane.

[0040] It should be noted that the observation regions in these cross-sections ab, bc, and ca follow the observation regions in step (a1).

[0041] For the through-hole P max After observing the cross-section ab, the cross-section bc, and the cross-section ca, find the through-hole P cut by a line orthogonal to the central axis of the through-hole P max The maximum length in the inner diameter of the through-hole P max Take the maximum value among the maximum lengths of the cross-section ab, the cross-section bc, and the cross-section ca as the maximum aperture L of the through-hole P max of the through-hole P

[0042] (a3) Furthermore, in the cross-section where the above maximum aperture L is determined, take the minimum length in the inner diameter of the through-hole P cut by a line orthogonal to the central axis of the through-hole P max as the minimum aperture S max of the through-hole P

[0043] Figure 4 is the cross-section 21 (any one of the cross-sections ab, bc, and ca) that determines the maximum aperture L25 of the through-hole P max 22. 23a and 23b are the outer periphery of the through-hole P max 22, and 24 is the central axis of the through-hole P max 22. In the cross-section 21 where the maximum aperture L25 is determined, the minimum length in the inner diameter of the through-hole P cut by a line orthogonal to the central axis 24 of the through-hole P max 22, which is 26, is the minimum aperture S max of the through-hole P

[0044] The values of the maximum aperture L and the minimum aperture S are not limited as long as the maximum aperture L / minimum aperture S is 1.0 to 2.0. However, for example, the maximum aperture L is and the minimum aperture S is for example

[0045] From the perspective of water absorption, it is preferable that the through-holes observed with the above space filling model do not cross other through-holes

[0046] 2. Decomposition start temperature

[0047] As shown in the following examples, after pretreatment by holding the MOF in an air atmosphere at a humidity of 25°C and a relative humidity of 50% for 12 hours, the temperature was raised at a rate of 5°C / minute under a nitrogen stream. When the temperature was raised to 500°C, in this temperature range (25 - 500°C), in the DTA measurement specified in the general rules for thermal analysis of JIS K0129, the point at which the decomposition behavior was observed was taken as the decomposition start temperature. A high decomposition start temperature means a strong bond between the metal ion and the organic ligand and a short distance between the metal ion and the organic ligand. It is speculated that if this distance is short, in the bond between the metal ion and the oxygen derived from the organic ligand, electrons on the organic ligand side are pulled to the metal side, so that the organic ligand side becomes an electron-deficient state, and it becomes easier to bond to the non-bonding electron pair on the oxygen atom of the water molecule, and thus it becomes easier to adsorb water.

[0048] The decomposition start temperature is preferably 210°C or higher, more preferably 220°C or higher, further preferably 230°C or higher, and in addition, it can also be 300°C or lower, and can also be 280°C or lower. The decomposition start temperature can also be 245°C or higher and 265°C or lower.

[0049] The metal ion constituting the MOF is an ion of at least one metal selected from the group consisting of Al, Ga, In, Ti, V, Cr, Mn, Fe, Co, Cu, Zr, and Hf, more preferably at least one selected from the group consisting of Al, Ga, In, Ti, V, Co, Zr, and Hf, further preferably an ion of at least one metal selected from the group consisting of Al, Co, and Zr, still further preferably Al and / or Zr ions, and particularly preferably Zr ions.

[0050] The organic ligand constituting the MOF contains at least one selected from the group consisting of carboxylato represented by R(COO - ) n (R is an n-valent group, and n is an integer of 2 or more and 3 or less). R is at least one of an unsaturated straight-chain hydrocarbon group, an aromatic hydrocarbon group, and a hydrocarbon group having an aromatic ring containing an oxygen atom, and it is a group that can have a functional group X of -OH or -S-S-.

[0051] The unsaturated straight-chain hydrocarbon group is preferably an unsaturated straight-chain hydrocarbon group having 2 to 24 carbon atoms, more preferably an unsaturated straight-chain hydrocarbon group having 2 to 12 carbon atoms, further preferably an unsaturated straight-chain hydrocarbon group having 2 to 4 carbon atoms, and particularly preferably -CH=CH-.

[0052] As the aromatic hydrocarbon group, it is preferably an aromatic hydrocarbon group having 6 to 30 carbon atoms and which is a group having a functional group X that may contain -OH or -S-S-, more preferably an aromatic hydrocarbon group having 6 to 14 carbon atoms and which is a group having a functional group X that may contain -OH or -S-S-, and still more preferably an aromatic hydrocarbon group having 6 to 12 carbon atoms and which is a group having a functional group X that may contain -OH or -S-S-. Specifically, examples include groups obtained by removing 2 or 3 hydrogen atoms from benzene or biphenyl and which are groups having a functional group X that may contain -OH or -S-S-.

[0053] In addition, as a hydrocarbon group having an aromatic ring containing an oxygen atom and which is a group having a functional group X (especially -OH) that may have -OH or -S-S-, examples include furan, oxazole, tetrahydropyran, etc. (i.e., groups obtained by removing 2 or 3 hydrogen atoms from them) and which are groups having a functional group X that may have -OH. Particularly preferred is furan (i.e., a group obtained by removing 2 or 3 hydrogen atoms from furan).

[0054] The above R is preferably at least one of an unsaturated straight-chain hydrocarbon group; an aromatic hydrocarbon group and which is a group having a functional group X that may have -OH or -S-S-; and a hydrocarbon group having an aromatic ring containing an oxygen atom, more preferably an unsaturated straight-chain hydrocarbon group having 2 to 4 carbon atoms; an aromatic hydrocarbon group having 6 to 12 carbon atoms and which is a group having a functional group X that may have -OH or -S-S-; and at least one of furan, oxazole, or tetrahydropyran, i.e., a hydrocarbon group having an aromatic ring containing an oxygen atom.

[0055] The number of carbon atoms of the above R is preferably 2 or more, and in addition, preferably 30 or less, more preferably 24 or less, still more preferably 18 or less, and still more preferably 12 or less.

[0056] The organic ligand constituting the MOF contains at least one selected from the group consisting of carboxylate groups represented by R(COO - )2 and R(COO - )3 (R has the same meaning as above). Specifically, examples include organic ligands obtained by removing 2 protons from the 2 carboxyl groups (-COOH) of a dicarboxylic acid or organic ligands obtained by removing 3 protons from the 3 carboxyl groups of a tricarboxylic acid.

[0057] Examples of the dicarboxylic acid include fumaric acid, 1,4-butenedicarboxylic acid, acetylenedicarboxylic acid, 1,2-benzenedicarboxylic acid (phthalic acid), 1,3-benzenedicarboxylic acid (isophthalic acid), 1,3-butadiene-1,4-dicarboxylic acid, 1,4-benzenedicarboxylic acid (terephthalic acid), 2,5-dihydroxyterephthalic acid, 2,2'-dithiobisbenzoic acid, perylene-3,9-dicarboxylic acid, 4,4'-dihydroxybiphenyl-3,3'-dicarboxylic acid, 1,1'-binaphthalene dicarboxylic acid, phenylindane dicarboxylic acid, naphthalene-1,8-dicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 2,3-naphthalenedicarboxylic acid, anthracene-2,3-dicarboxylic acid, 2',3'-diphenyl-p-terphenyl-4,4''-dicarboxylic acid, 5-tert-butyl-1,3-benzenedicarboxylic acid, 5-hydroxy-1,3-benzenedicarboxylic acid, 2,5-dihydroxy-1,4-benzenedicarboxylic acid, furan-2,5-dicarboxylic acid, 1-nonene-6,9-dicarboxylic acid, or eicosenedicarboxylic acid, etc. The dicarboxylic acid is preferably at least one selected from the group consisting of fumaric acid, 2,2'-dithiobisbenzoic acid, terephthalic acid, 4,4'-dihydroxybiphenyl-3,3'-dicarboxylic acid, and 2,5-furandicarboxylic acid.

[0058] Examples of the tricarboxylic acid include aconitic acid, trimellitic acid, benzene-1,3,5-tricarboxylic acid (trimesic acid), biphenyl-3,4',5-tricarboxylic acid, 1,3,5-tris(4-carboxyphenyl)benzene, etc., and trimesic acid is particularly preferred.

[0059] The above R is preferably any one of the following (A-1) to (A-11).

[0060] [Chemical formula 1]

[0061]

[0062] In the above (A-1) to (A-11), at least one of the hydrogen atoms bonded to the carbon atom may be substituted with -OH, and it means bonding to (COO - ) at the *, and -X- in formulas (A-4) to (A-6) is -S-S- or a single bond.

[0063] As the organic ligand constituting the MOF of the present invention, an organic ligand different from the carboxylate group represented by the above R(COO - ) n may be further included. Examples of such an organic ligand include at least one selected from the group consisting of urea, pyrazine, oxazole, isoxazole, thiazole, imidazole, pyrazole, 1,2,3-thiadiazole, pyridazine, pyrimidine, purine, pteridine, 2,2'-bipyridine, and 4,4'-bipyridine, and 4,4'-bipyridine is particularly preferred.

[0064] The molar ratio of the metal ion to the organic ligand (in many cases, the total amount) (metal ion / organic ligand) is preferably 0.1 or more, more preferably 0.5 or more, further preferably 0.9 or more, and further preferably 10 or less, more preferably 5 or less, and further preferably 4 or less. This molar ratio is particularly preferably 0.9 or more and 4 or less.

[0065] Next, the method for producing the MOF of the present invention will be described. The MOF of the present invention can be obtained by reacting a metal compound containing a metal ion constituting the MOF with one or more organic compounds that are organic ligands constituting the MOF in a solvent. In addition, it is also preferable to mix an inorganic compound that is an inorganic ligand with the above metal compound or organic compound in the solvent as needed.

[0066] Specifically, it is preferable to prepare a solution A obtained by first completely dissolving either a metal compound containing a metal ion or an organic compound that is an organic ligand in a solvent, and then dropwise adding the other (in this case, it is also preferable to dropwise add a solution B obtained by dissolving the other in a solvent). In addition, it is also preferable to prepare a solution X obtained by completely dissolving both a metal compound containing a metal ion and an organic compound that is an organic ligand in a solvent, and then dropwise adding a metal compound or organic compound of a different type from the metal compound and organic compound in solution X, or dropwise adding a solution Y obtained by completely dissolving a metal compound or organic compound of a different type from the metal compound and organic compound in solution X in a solvent. The temperature of the dropwise addition is preferably room temperature (specifically, around 20 to 30 °C). In addition, it is preferably added dropwise such that the amount of the metal compound or organic compound added dropwise is 1.0 mmol / min or less. The dropping rate is preferably 0.8 mmol / min or less, more preferably 0.3 mmol / min or less, and can also be 0.01 mmol / min or more and can also be 0.03 mmol / min or more. It is particularly preferable to dropwise add a metal compound in a liquid obtained by dissolving an organic compound in a solvent or a liquid obtained by dissolving a metal compound in a solvent, and at this time, it is further preferable to add dropwise at the above dropping rate.

[0067] The metal compound containing a metal ion constituting the MOF is preferably a sulfate, nitrate, acetate, chloride, bromide, or alkoxide of a metal, and particularly preferably a nitrate, chloride, or bromide of a metal.

[0068] The organic compound that is an organic ligand constituting the MOF contains one or more selected from the group consisting of polycarboxylic acids represented by R(COOH) n R and n are the same as those in the above R(COO - ) nR and n in the represented carboxylate group have the same meanings, and all cases including the preferred ones can refer to the above explanations of R and n.

[0069] The organic compound serving as the organic ligand preferably contains a dicarboxylic acid or a tricarboxylic acid, and specific examples thereof can refer to the dicarboxylic acid or tricarboxylic acid described in the carboxylate group represented by R(COO - ) n including the preferred range.

[0070] As the organic compound serving as the organic ligand, preferably in addition to one or more selected from the group consisting of polycarboxylic acids represented by R(COOH) n at least one selected from the group consisting of urea, pyrazine, oxazole, isoxazole, thiazole, imidazole, pyrazole, 1,2,3-thiadiazole, pyridazine, pyrimidine, purine, pteridine, 2,2'-bipyridine, and 4,4'-bipyridine is further used. In addition, as the inorganic compound serving as the inorganic ligand, an alkali metal hydroxide or an alkali metal azide is preferably used. In addition, OH - , O 2- , or an inorganic ligand of OH2 may be included in the MOF due to a solvent such as a dissolved metal compound or an organic compound, moisture in the air, etc.

[0071] The solvent for dissolving the metal compound containing metal ions or the organic compound serving as the organic ligand is preferably water; alcohol solvents such as methanol and ethanol; fatty acid solvents such as formic acid and acetic acid; amide solvents such as dimethylformamide, etc. One kind can be used alone, or two or more kinds can be mixed and used.

[0072] When preparing solution A, solution B, or solution X obtained by completely dissolving the metal compound containing metal ions, the ratio of the metal compound to the solvent (metal compound / solvent) in these solutions is preferably 0.01 mol / L or more, more preferably 0.1 mol / L or more, further preferably 1 mol / L or less, more preferably 0.7 mol / L or less, and still more preferably 0.6 mol / L or less.

[0073] When preparing solution A, solution B, or solution X obtained by completely dissolving the organic compound serving as the organic ligand, the ratio of the organic compound to the solvent (organic compound / solvent) in these solutions is preferably 0.01 mol / L or more, more preferably 0.02 mol / L or more, further preferably 0.04 mol / L or more, further preferably 1 mol / L or less, more preferably 0.7 mol / L or less, and still more preferably 0.5 mol / L or less.

[0074] In addition, when an inorganic compound that becomes an inorganic ligand is included in Solution A, Solution B, or Solution X, the ratio of the inorganic compound to the solvent (inorganic compound / solvent) in these solutions is preferably 0.05 mol / L or more, and more preferably 1 mol / L or less.

[0075] Regarding the molar ratio of the metal compound containing a metal ion to the organic compound that becomes an organic ligand, the ratio of the molar amount of the metal atoms in the metal compound to the molar amount of the organic compound may be adjusted so as to be equal to the molar ratio of the above-described metal ion to the organic ligand.

[0076] After the above-described dropping is completed, it is important to perform at least any one of refluxing, stirring, and standing at a temperature of room temperature (e.g., 25°C) to 200°C for about 5 minutes to 100 hours. More specifically, when the temperature is from room temperature to less than 100°C, it is important to react the metal compound with the organic compound for 72 hours or more, when the temperature is 100°C or more and less than 130°C, for 20 hours or more, and when the temperature is 130°C or more, for 15 hours or more. By separating the obtained reaction product from the solvent by centrifugation or filtration, etc., and performing washing and drying, the target MOF can be obtained.

[0077] This application claims priority based on Japanese Patent Application No. 2022-174075 filed on October 31, 2022 and Japanese Patent Application No. 2022-174076 filed on October 31, 2022. The entire contents of the specifications of Japanese Patent Application No. 2022-174075 filed on October 31, 2022 and Japanese Patent Application No. 2022-174076 filed on October 31, 2022 are incorporated herein by reference.

[0078] Examples

[0079] Hereinafter, the present invention will be described more specifically by way of examples. The present invention is not limited to the following examples, and of course, it can also be appropriately modified and implemented within the scope suitable for the above-described and hereinafter-described gists, and they are all included in the technical scope of the present invention.

[0080] Example 1

[0081] In a 100 mL eggplant-shaped flask, 5.00 mmol of fumaric acid, 10 mL of DMF, and 3.5 mL of formic acid were mixed at 25 °C until completely dissolved to obtain Solution A. Additionally, Solution B was prepared by mixing 4.97 mmol of zirconium oxychloride octahydrate, 10 mL of DMF, and 3.5 mL of formic acid at 25 °C until completely dissolved. Solution B was added dropwise to Solution A at 25 °C over 1 hour. In Solution A, the ratio of fumaric acid to the solvent was 0.370 mol / L, and in Solution B, the ratio of zirconium oxychloride octahydrate to the solvent was 0.368 mol / L. The dropping rate of zirconium oxychloride octahydrate was 0.0828 mmol / min. Subsequently, it was left standing at 130 °C for 1 day to obtain a suspension. The resulting precipitate solid was washed and filtered 3 times with 20 mL of DMF, then washed and filtered 3 times with 20 mL of isopropyl alcohol. The obtained filter cake was dried under reduced pressure in a vacuum drying oven at 120 °C for 24 hours to obtain 1.00 g of the product (yield 84.2%).

[0082] Example 2

[0083] In a 1 L eggplant-shaped flask, 3.05 mmol of cobalt(II) hexahydrate, 10.42 mmol of 2,2'-dithiobisbenzoic acid, 10.40 mmol of sodium azide, and 150 mL of DMF were mixed at 25 °C until completely dissolved to obtain Solution A. Additionally, Solution B was prepared by mixing 3.08 mmol of benzene tricarboxylic acid, 3.10 mmol of 4,4'-bipyridine, and 150 mL of ethanol until completely dissolved. Solution B was added dropwise to Solution A at 25 °C over 3 hours. In Solution A, the ratio of cobalt(II) hexahydrate to the solvent was 0.0203 mol / L, and the ratio of 2,2'-dithiobisbenzoic acid to the solvent was 0.0695 mol / L. In Solution B, the combined ratio of benzene tricarboxylic acid and 4,4'-bipyridine to the solvent was 0.0412 mol / L. Moreover, the dropping rate of the combined amount of benzene tricarboxylic acid and 4,4'-bipyridine was 0.0343 mmol / min. Subsequently, it was stirred at 25 °C for 4 days to obtain a suspension. The resulting precipitate solid was washed and filtered 3 times with 30 mL of DMF. The obtained filter cake was dried under reduced pressure in a vacuum drying oven at 120 °C for 24 hours to obtain 1.16 g of the product (yield 90.0%).

[0084] Example 3

[0085] In a 100 mL pressure-resistant container made of SUS-304 (including a Teflon (registered trademark) inner cylinder tube), 0.50 mmol of terephthalic acid was mixed with 20 mL of methanol and completely dissolved to obtain Solution A. Solution B, which was obtained by mixing 3.69 mmol of Al(NO3)3·9H2O with 20 mL of methanol and completely dissolving it, was added dropwise to Solution A at 25 °C over 30 minutes. 1.57 g of 2M NaOH in MeOH (0.2 g / 2.5 ml) was added, and a stir bar was placed and stirred for 5 minutes. In Solution A, the ratio of terephthalic acid to the solvent was 0.0250 mol / L, and in Solution B, the ratio of Al(NO3)3·9H2O to the solvent was 0.185 mol / L. The dropping rate of Al(NO3)3·9H2O was 0.123 mmol / minute. Thereafter, it was allowed to stand at 125 °C for 20 hours. The resulting precipitate solid was washed and filtered three times with 30 mL of methanol, and the obtained filter cake was dried under reduced pressure in a vacuum drying oven at 120 °C for 24 hours and 150 °C for 24 hours to obtain 0.12 g of the product (yield 70.0%).

[0086] Example 4

[0087] In a 50 mL eggplant-shaped flask, 5.04 mmol of 2,5-furandicarboxylic acid, 10.59 mmol of NaOH, and 15 mL of ion-exchanged water were mixed and completely dissolved to obtain Solution A. Solution B, which was obtained by mixing 5.04 mmol of AlCl3·6H2O with 10 mL of ion-exchanged water and completely dissolving it, was added dropwise to Solution A at 25 °C over 30 minutes. In Solution A, the ratio of 2,5-furandicarboxylic acid to the solvent was 0.336 mol / L, and in Solution B, the ratio of AlCl3·6H2O to the solvent was 0.504 mol / L. The dropping rate of AlCl3·6H2O was 0.168 mmol / minute. Thereafter, it was refluxed at 100 °C for 24 hours to obtain a suspension. The resulting precipitate solid was centrifugally washed three times with 50 mL of water, and the obtained filter cake was dried in a vacuum drying oven at 80 °C for 24 hours to obtain 0.67 g of the product (yield 67%).

[0088] Comparative Example 1

[0089] In a 50 mL pressure-resistant container made of SUS-304 (including a Teflon (registered trademark) inner cylinder tube), 3.0 mmol of 2-aminoterephthalic acid was completely dissolved in 25 mL of a mixture of dimethylformamide (DMF) and MeOH at a volume ratio of 1 / 1 to obtain Solution A. At 25 °C, 1.518 mmol of Ti[OCH(CH3)2]4 was added thereto all at once, and a magnetic stir bar was placed and stirred for 5 minutes. Thereafter, it was allowed to stand at 150 °C for 16 hours. The resulting precipitate solid was washed and filtered 3 times with 10 mL of DMF, and the obtained filter cake was dried under reduced pressure in a vacuum drying oven at 120 °C for 24 hours and 150 °C for 24 hours to obtain 0.62 g of the product substance (yield 89.4%).

[0090] Comparative Example 2

[0091] In a 100 mL pressure-resistant container made of SUS-304 (including a Teflon (registered trademark) inner cylinder tube), 7.483 mmol of terephthalic acid was completely dissolved in 25 mL of a mixture of dimethylformamide (DMF) and MeOH at a volume ratio of 9 / 1 to obtain Solution A. At 25 °C, Solution A was added dropwise all at once to 4.523 mmol of Ti[OCH(CH3)2]4 and mixed, and a magnetic stir bar was placed and stirred for 5 minutes. Thereafter, it was allowed to stand at 150 °C for 16 hours. The resulting precipitate solid was washed and filtered 3 times with 10 mL of DMF, and the obtained filter cake was dried under reduced pressure in a vacuum drying oven at 120 °C for 24 hours and 150 °C for 24 hours to obtain 0.35 g of the product substance (yield 24.6%).

[0092] Comparative Example 3

[0093] In a 100 mL pressure-resistant container made of SUS-304 (including a Teflon (registered trademark) inner cylinder tube), 3.178 mmol of 1H-1,2,3-triazole and 1.521 mmol of 2,5-thiophenedicarboxylic acid were dissolved in 56.64 g of dimethylformamide (DMF) to obtain Solution A. At 25 °C, 5.268 mmol of Zn(NO3)2·6H2O was added thereto all at once and mixed, and a magnetic stir bar was placed and stirred for 20 minutes. Thereafter, 1.522 mmol of terephthalic acid was further mixed at 25 °C, and a magnetic stir bar was placed and stirred for 20 minutes, and then stirred at 100 °C for 48 hours to obtain a suspension. The resulting precipitate solid was washed and filtered 3 times with 30 mL of DMF, and the obtained filter cake was dried under reduced pressure in a vacuum drying oven at 120 °C for 24 hours to obtain 0.65 g of the product substance (yield 66.2%).

[0094] Comparative Example 4

[0095] After dropping and adding Solution B to Solution A, the mixture was refluxed at 25 °C for 18 hours. Otherwise, the same operations as in Example 4 were carried out to obtain the generated substance.

[0096] (1) Measurement of porosity

[0097] The substances generated in the examples and comparative examples were subjected to XRD measurement under the following conditions to obtain a cif file. The cif file was read into software such as Mercury, and the probe radius input as Void contact surface was entered in the obtained data. Approx.Grid Spacing: The porosity was calculated.

[0098] Apparatus: SmartLab manufactured by Rigaku

[0099] X-ray source: Cu

[0100] Measurement range: 2θ = 3 - 40°

[0101] Step size: 0.01°

[0102] Scanning speed: 3° / min

[0103] Measurement temperature: Room temperature (25 °C)

[0104] (2) Measurement of the maximum pore diameter L and the minimum pore diameter S

[0105] From the drawing of Mercury obtained during the above porosity measurement, the crystal structure including the pore size and pore shape was obtained, and the maximum pore diameter L and the minimum pore diameter S were determined according to the above steps (a1) to (a3).

[0106] (3) Measurement of the decomposition start temperature

[0107] After the obtained MOF was pretreated by holding it in an air atmosphere with a humidity control of 25 °C and a relative humidity of 50% for 12 hours, it was heated at a heating rate of 5 °C / min under a nitrogen flow. When the temperature was raised to 500 °C, in this temperature range (25 - 500 °C), in the DTA measurement specified in the general rules of thermal analysis of JIS K0129, the point where the decomposition behavior was observed was taken as the decomposition start temperature.

[0108] (4) Measurement of the water absorption amount at a relative pressure (P / P0) (P is the water vapor pressure, P0 is the saturated water vapor pressure) = 0.1

[0109] Pretreatment conditions:

[0110] (i) Heat the sample from 100 °C to a temperature 50 °C lower than the decomposition start temperature of the respective MOF, and perform vacuum drying for 12 hours.

[0111] (ii) Connect to the pretreatment device (BELPREP VACII), evacuate the air in the sample tube, and then introduce N2 gas (purity 99.999% or higher) to atmospheric pressure.

[0112] (iii) After that, remove the sample tube from the pretreatment device, measure the weight 3 times using a precision balance (displaying 4 or more digits after the decimal point), and obtain the average (W1). When using the precision balance, an ion generator is used to eliminate the influence of static electricity.

[0113] (iv) Weigh approximately 50 mg of the sample to be measured, and directly place the sample into the spherical part at the lower part of the standard sample tube using a long-stem funnel.

[0114] (v) Return the glass rod to the sample tube, stopper it quickly with a quick-sealing plug, then measure the total weight once to temporarily confirm the added sample amount. Connect the sample tube containing the sample to the pretreatment device and evacuate the sample tube.

[0115] (vi) After achieving a sufficiently low pressure in the sample tube, start heating (while continuing to evacuate).

[0116] Measurement device: BELSORP-max manufactured by MicrotracBEL Co., Ltd.

[0117] Measurement conditions:

[0118] (i) The water adsorption amount in weight percentage (wt%) is calculated as (water adsorption amount / (amount of measured sample) × 100) by inputting the sample weight, information on water at the measurement temperature (such as saturated vapor pressure, etc.), and setting the measurement relative pressure, etc. to be measured in the measurement software, and then starting the measurement.

[0119] (ii) Ultrapure water as the adsorption substance is placed in the solvent reservoir and connected to the device, and then at least 3 degassing treatments are performed (immerse the solvent reservoir in liquid nitrogen filled in a Dewar flask to freeze the ultrapure water).

[0120] (iii) After confirming sufficient freezing, open the valve at the upper part of the solvent reservoir to set the solvent reservoir to a vacuum. Close the valve at the upper part of the solvent reservoir, melt the frozen water, and take out the air contained in the ultrapure water as gas to complete the preparation of the adsorption substance.

[0121] (iv) Input the sample weight, information on water at the measurement temperature (such as saturated vapor pressure, etc.), set the measurement relative pressure, etc. to be measured in the measurement software, and press the measurement start button.

[0122] (v) Thereafter, set up a Dewar flask filled with liquid nitrogen or set up a sample test tube according to the instructions of the software, and conduct the measurement.

[0123] (vi) Derive the water absorption amount at a relative pressure (P / P0) (where P is the water vapor pressure and P0 is the saturated water vapor pressure) of 0.1 from the obtained results.

[0124] The results are shown in Table 1.

[0125]

[0126] In Examples 1 to 4, crystalline MOFs with a maximum pore diameter L / minimum pore diameter S of 1.0 to 2.0 and a decomposition start temperature exceeding 200 °C were obtained. In contrast, the MOFs of Comparative Examples 1 to 3 did not satisfy at least one of the requirements of the maximum pore diameter L / minimum pore diameter and the decomposition start temperature. In addition, in Comparative Example 4, due to inappropriate reflux conditions after dropping solution B into solution A, no crystalline substance could be confirmed by the measurement using XRD. It should be noted that the through holes P observed in Example 2, Example 3, Comparative Example 1, Comparative Example 2, and Comparative Example 3 max intersect with other through holes.

[0127] Industrial applicability

[0128] The MOF of the present invention can be suitably used, for example, for the adsorption and removal of gases and organic molecules. Examples of the gas include water (water vapor), carbon dioxide, hydrogen, carbon monoxide, oxygen, nitrogen, hydrocarbons having 1 to 4 carbon atoms, noble gases, hydrogen sulfide, ammonia, sulfur oxides, nitrogen oxides, siloxanes, etc. Examples of the organic molecule include hydrocarbons having 5 to 8 carbon atoms, alcohols having 1 to 8 carbon atoms, aldehydes having 1 to 8 carbon atoms, carboxylic acids having 1 to 8 carbon atoms, ketones having 1 to 8 carbon atoms, amines having 1 to 8 carbon atoms, esters having 1 to 8 carbon atoms, amides having 1 to 8 carbon atoms, etc. It should be noted that the above organic molecules may also contain an aromatic ring.

[0129] Explanation of reference numerals

[0130] 11 Inscribed circle

[0131] 21 Cross-section

[0132] 22 Through hole P max

[0133] 23a, 23b Through hole P max Periphery of

[0134] 24 Through hole P max Central axis of

[0135] 25 Maximum pore diameter L

[0136] 26 Minimum aperture S

Claims

1. A metal-organic structure which is a metal-organic structure composed of an organic ligand and a metal ion, wherein, The organic ligand comprises R(COO - ) n An organic ligand represented by, wherein R is at least one of an unsaturated straight-chain hydrocarbon group, an aromatic hydrocarbon group, and a hydrocarbon group having an aromatic ring containing an oxygen atom, and is a group that may have a functional group X of -OH or -SS-, and n is 2 or more and 3 or less, the metal ion is an ion of at least one metal selected from the group consisting of Al, Ga, In, Ti, V, Cr, Mn, Fe, Co, Cu, Zr and Hf, for the metal-organic structure, the ratio (maximum pore diameter L / minimum pore diameter S) determined by the following steps (a1) to (a3) is 1.0 to 2.0, the decomposition start temperature of the metal-organic structure exceeds 200 °C, (a1) Represent the crystal structure determined by X-ray crystal structure analysis in a space-filling model, and represent the outer periphery of the through-hole without omission. Observe the presence or absence of the through-hole from all directions, and specify the through-hole P with the largest inscribed circle diameter. max , (a2) within the through-hole P max In each of the cross-sections ab, bc, and ca of the through-hole P max , find the maximum length of the inner diameter of the through-hole P cut by a line orthogonal to the central axis of the through-hole P max , and take the maximum of the maximum lengths of the cross-sections ab, bc, and ca respectively as the maximum aperture L of the through-hole P max ; Among them, the so-called cross-section ab is a through-hole P within a plane parallel to the a-b plane of the unit cell max is a cut surface and is a surface cut in a state where the through-hole P max passes through. In the case where there are multiple cross-sections that can cut the through-hole P in a state where it passes through max the cross-section with the largest overlap with the through-hole P max is called the cross-section ab; moreover, in the specification of the cross-section ab, the cross-section obtained by replacing the cross-section ab with the cross-section bc and replacing the a-b plane with the b-c plane is the cross-section bc, and the cross-section obtained by replacing the cross-section ab with the cross-section ca and replacing the a-b plane with the c-a plane is the cross-section ca; (a3) In the cross-section where the maximum aperture L is determined, the minimum inner diameter length of the through-hole P cut by a line orthogonal to the central axis of the through-hole P max is taken as the minimum aperture S. max ​ 2. The metal-organic structure according to claim 1, wherein, when representing the crystal structure of the metal-organic structure determined by X-ray crystal structure analysis in a space-filling model, the observed through-holes do not cross other through-holes.

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