Metal-organic structures and methods for manufacturing the same

Abstract

The purpose of the present invention is to provide an MOF which has excellent desorption performance. The present invention provides a metal organic framework which is composed of a specific organic ligand and a specific metal ion, wherein: the void fraction is 20% to 75%; and the ratio ((largest hole diameter L) / (smallest hole diameter S)) of the largest hole diameter L to the smallest hole diameter S as determined by the steps (a1) to (a3) described below is 1.06 or more. (a1) A crystal structure determined by X-ray crystallographic analysis is displayed as a space-filling model and the presence or absence of a through hole is determined by the observation under specific conditions, so that a through hole Pmax having the maximum inscribed circle diameter is identified. (a2) The maximum length among the inner diameters of the through hole Pmax is determined in a specific cross-section of the through hole Pmax, so that the largest hole diameter L of the through hole Pmax is identified. (a3) The smallest hole diameter S is identified in the cross-section in which the largest hole diameter L is determined.

Description

metal organic framework

[0001] The present invention relates to a metal-organic framework.

[0002] Metal organic frameworks, also known as porous coordination polymers, are one type of material that form a porous structure through coordination bonds between metal ions and organic ligands, and are expected to be used for gas adsorption / desorption, catalysts, etc.

[0003] For example, Patent Document 1 discloses a metal organic framework including a metal ion, a first ligand, a second ligand, and an optional third ligand, in which the metal ion is an aluminum ion, the first and second ligands are organic compound ions composed of heterocycles having two carboxy groups, the angle formed between the heteroatom and the carboxy group satisfies a predetermined condition, the third ligand is an organic compound ion having two carboxy groups, and the abundance ratios of the first to third ligands are within a predetermined range.

[0004] Japanese Patent Application Laid-Open No. 2020-176101

[0005] Metal-organic frameworks (hereinafter sometimes referred to as MOFs) can be regenerated and reused by adsorbing substances such as water, carbon dioxide, and hydrogen, and then heating them to a predetermined temperature to desorb the adsorbed substances from the MOF. However, it is desirable to be able to efficiently desorb the adsorbed substances at this time.

[0006] Therefore, an object of the present invention is to provide an MOF with excellent desorption performance.

[0007] The present invention that has achieved the above object is as follows: [1] A metal-organic framework comprising an organic ligand and a metal ion, wherein the porosity is 20 to 75%, 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 the following steps (a1) to (a3) ​​is 1.06 or more, and the organic ligand is R(COO-) ｎ wherein R is an aromatic hydrocarbon group or pyrrole, and —OH, —NH ２or -S-S-, wherein n is 2 or more and 3 or less, and 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. (a1) A crystal structure determined by X-ray crystal structure analysis is displayed as a space-filling model, and the periphery of each through-hole is displayed without being missing. The presence or absence of a through-hole is observed from all directions, and the through-hole P having the largest diameter of the inscribed circle is selected. ｍａｘ (a2) The through hole P ｍａｘ In each of the cross sections ab, bc, and ca, the through hole P ｍａｘ A through hole P cut along a line perpendicular to the central axis of ｍａｘ The maximum length of the inner diameter of the cross section ab, cross section bc, and cross section ca is determined as the maximum length of the through hole P ｍａｘ The maximum hole diameter L is the cross section ab of the through hole P on a plane parallel to the a-b plane of the unit lattice. ｍａｘ A cross section of the through hole P ｍａｘ is a surface that is cut out in a state where the through hole P ｍａｘ If there are multiple cross sections that can be cut out, ｍａｘ The cross section with the largest overlapping is called cross section ab. In addition, in specifying the cross section ab, cross section ab is read as cross section bc and the a-b plane is read as cross section bc, and cross section ab is read as cross section ca and the a-b plane is read as cross section ca. (a3) ​​In the cross section where the maximum hole diameter L is determined, ｍａｘ A through hole P cut along a line perpendicular to the central axis of ｍａｘ The minimum length of the inner diameters is defined as the minimum pore diameter S. [2] The metal organic structure according to [1], wherein the ratio of the maximum pore diameter L to the minimum pore diameter S (maximum pore diameter L / minimum pore diameter S) is 4.0 or less.

[0008] According to the present invention, the desorption performance of MOFs can be improved.

[0009] 1 shows an example of the crystal structure of the MOF of Example 3 displayed as a space-filling model, observed from one direction. 2 shows an example of the crystal structure of the MOF of Example 3 displayed as a space-filling model, observed from another direction. 3 shows an example of the crystal structure of the MOF of Example 3 displayed as a space-filling model, observed from yet another direction. Through-hole P ｍａｘ 1 is a diagram showing the maximum pore diameter L and the minimum pore diameter S of the

[0010] The MOF of the present invention is composed of organic ligands and metal ions, has a porosity of 20 to 75%, and has a ratio of the maximum pore size L to the minimum pore size S (maximum pore size L / minimum pore size S) determined by a predetermined procedure of 1.06 or more. When the porosity is equal to or greater than a predetermined value, adsorbed substances are easily desorbed, and when the ratio of maximum pore size L / minimum pore size S is equal to or greater than a predetermined value, the surface area inside the MOF tends to be large, making it easier to adsorb substances such as water, carbon dioxide, and hydrogen.

[0011] 1. Porosity The porosity of the MOF of the present invention is 20 to 75%, preferably 25% or more, more preferably 30% or more, even more preferably 40% or more, and is preferably 70% or less, more preferably 65% ​​or less, even more preferably 60% or less. From the viewpoint of increasing the desorption amount, the porosity may be 30% or more and 45% or less.

[0012] As shown in the examples below, the porosity can be obtained by measuring the MOF of the present invention by XRD (X-ray diffraction), obtaining a cif (Crystalographic Information File) file, reading it into software called Mercury (The Cambridge Crystallographic Data Centre), and based on the obtained information, inputting a void contact surface probe radius of 1.5 Å and an approximate grid spacing of 0.7 Å.

[0013] 2. Ratio of maximum pore diameter L to minimum pore diameter S (maximum pore diameter L / minimum pore diameter S) The ratio of maximum pore diameter L / minimum pore diameter S is 1.06 or more, preferably 1.09 or more, more preferably 1.11 or more, even more preferably 1.17 or more, and most preferably 2.0 or more, and is preferably 4.0 or less, more preferably 3.5 or less, and even more preferably 3.0 or less.

[0014] The maximum pore size L / minimum pore size S is determined by the following steps (a1) to (a3).

[0015] (a1) The crystal structure determined by X-ray crystal structure analysis is displayed as a space-filling model, and the periphery of the through-hole is displayed without being missing. The presence or absence of a through-hole is observed from all directions, and the through-hole P with the largest diameter of the inscribed circle is identified. ｍａｘ Identify.

[0016] As in the measurement of the porosity, X-ray crystal structure analysis is performed by XRD measurement to obtain a cif file, and when the cif file is read into the Mercury, a single space-filling model (crystal structure) is obtained.

[0017] After obtaining a space-filling model of the crystal structure, the periphery of the through-hole is displayed without missing any part, and the crystal structure is rotated to observe the presence or absence of the through-hole from all directions. Figures 1 to 3 show the appearance when the obtained crystal structure is rotated and the through-hole is observed from a predetermined direction. Figure 3 shows the inscribed circle 11 when the through-hole is observed from the direction shown in Figure 3, and such an inscribed circle is identified for all the through-holes observed from each direction, and the through-hole P with the largest diameter of the inscribed circle among all the through-holes observed is selected. ｍａｘ (a1) In order to observe all of the through holes without any missing peripheries, first, observation is performed using one unit lattice, and if there are through holes with missing peripheries, an area 2 × 2 × 2 times the unit lattice may be displayed and observed.

[0018] (a2) Next, through hole P ｍａｘ The cross section ab is a plane parallel to the a-b plane of the unit lattice. ｍａｘ A cross section of the through hole Pｍａｘ It is a plane parallel to the a-b plane of the unit lattice, and the through hole P ｍａｘ There may be a plurality of cross sections that can be cut out. When there are a plurality of cross sections, the through hole P ｍａｘ The cross section with the largest overlap is called cross section ab. Cross section bc is a cross section obtained by replacing cross section ab with cross section bc and the a-b plane with the bc plane in the specification of cross section ab. Cross section ca is a cross section obtained by replacing cross section ab with cross section ca and the a-b plane with the ca plane. The observation areas in these cross sections ab, bc, and ca follow the observation areas in step (a1).

[0019] Through hole P ｍａｘ After observing the cross sections ab, bc, and ca, the through hole P ｍａｘ A through hole P cut along a line perpendicular to the central axis of ｍａｘ The maximum length of the inner diameter of the cross section ab, cross section bc, and cross section ca is determined as the maximum length of the through hole P ｍａｘ The maximum hole diameter is L.

[0020] (a3) Furthermore, in the cross section where the maximum hole diameter L is determined, the through hole P ｍａｘ A through hole P cut along a line perpendicular to the central axis of ｍａｘ The minimum length of the inner diameter of the hole is defined as the minimum hole diameter S.

[0021] FIG. 4 shows the through hole P ｍａｘ The cross section 21 (one of the cross sections ab, bc, and ca) determines the maximum hole diameter L25 of the through hole P22. ｍａｘ 22 is the outer periphery of the through hole P ｍａｘ The cross section 21 where the maximum hole diameter L25 is determined is the central axis of the through hole P ｍａｘ The through hole P is cut along a line perpendicular to the central axis 24 of the ｍａｘ The minimum length 26 of the inner diameter 22 is the minimum hole diameter S.

[0022] The value of maximum pore diameter L / minimum pore diameter S determined in this manner being 1.06 or more means that the shape of the through holes is tortuous, and the surface area inside the through holes is large, which is thought to make it easier for substances such as water, carbon dioxide, and hydrogen to be adsorbed.

[0023] The values ​​of the maximum pore diameter L and the minimum pore diameter S are not limited as long as the ratio of maximum pore diameter L / minimum pore diameter S is 1.06 or more, but the maximum pore diameter L is, for example, 2.5 to 20 Å, and the minimum pore diameter S is, for example, 1.5 to 15 Å.

[0024] The metal ions constituting the MOF are ions of at least one metal selected from the group consisting of Al, Ga, In, Ti, V, Cr, Mn, Fe, Co, Cu, Zr, and Hf, preferably ions of at least one metal selected from the group consisting of Al, Ga, In, Ti, V, Co, Zr, and Hf, more preferably ions of at least one metal selected from the group consisting of Al, Ga, In, Ti, V, Zr, and Hf, even more preferably ions of at least one metal selected from the group consisting of Al, In, and Ti, and particularly preferably Al ions, or In and / or Ti ions.

[0025] The organic ligands constituting the MOF are R(COO － ) ｎ where R is an aromatic hydrocarbon group or pyrrole, and —OH, —NH ２ or a group which may have a functional group X which is -SS-, and n is 2 or more and 3 or less, and contains at least one kind of organic ligand.

[0026] The preferred ranges of the number of carbon atoms in the aromatic hydrocarbon group are, in order, 6 or more and 30 or less, 6 or more and 24 or less, 6 or more and 18 or less, 6 or more and 12 or less, and 6 or more and 10 or less. Specifically, the aromatic hydrocarbon group is a group obtained by removing n (preferably 2 or 3) hydrogen atoms from benzene or biphenyl, and the functional group X (particularly -OH, -NH ２ or —S—S—).

[0027] R (COO － ) ｎis R(COOH) ｎ It is obtained by removing n protons from

[0028] The above-mentioned R(COOH) ｎ Among these, those in which n is 2, that is, dicarboxylic acids, include 1,2-benzenedicarboxylic acid (phthalic acid), 1,3-benzenedicarboxylic acid (isophthalic acid), 1,4-benzenedicarboxylic acid (terephthalic acid), 2-aminoterephthalic acid, 2,5-dihydroxyterephthalic acid, 2,2'-dithiodibenzoic acid, perylene-3,9-dicarboxylic acid, 4,4'-dihydroxybiphenyl-3,3'-dicarboxylic acid, 4,4'-diamino-1,1'-biphenyl-3,3'-dicarboxylic acid, 4,4'-diaminobiphenyl-3,3'-dicarboxylic acid, 1,1'-binaphthyldicarboxylic acid, phenylindanedicarboxylic acid, and naphthalene-1,8-dicarboxylic acid. acid, 1,4-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 12,3-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, 4,4'-dihydroxy-diphenylmethane-3,3'-dicarboxylic acid, 1H-pyrrole-2,5-dicarboxylic acid, 1-methylpyrrole-3,4-dicarboxylic acid, or 1-benzyl-1H-pyrrole-3,4-dicarboxylic acid. The dicarboxylic acid is preferably at least one selected from the group consisting of isophthalic acid, 1H-pyrrole-2,5-dicarboxylic acid, terephthalic acid, 2-aminoterephthalic acid, 2,2'-dithiodibenzoic acid, and 4,4'-dihydroxybiphenyl-3,3'-dicarboxylic acid.

[0029] The above-mentioned R(COOH) ｎAmong these, those in which n is 3, i.e., tricarboxylic acids, include trimellitic acid, trimesic acid (benzene tricarboxylate), biphenyl-3,4',5-tricarboxylic acid, 1,3,5-tris(4-carboxyphenyl)benzene, etc., and trimellitic acid, benzene tricarboxylate, or 1,3,5-tris(4-carboxyphenyl)benzene is preferred, with benzene tricarboxylate being particularly preferred.

[0030] The R is preferably any one of the following (A-1) to (A-10).

[0031]

[0032] In the above (A-1) to (A-10), at least one of the hydrogen atoms bonded to the carbon atom is —OH or —NH ２ may be substituted with, and —X— represents —S—S— or a single bond.

[0033] As the organic ligand constituting the MOF of the present invention, the above-mentioned R(COO － ) ｎ and examples of such organic ligands 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, with 4,4'-bipyridine being particularly preferred.

[0034] The molar ratio of metal ions to organic ligands (total amount when multiple types are used) (metal ions / organic ligands) is preferably 0.1 or more, more preferably 0.3 or more, even more preferably 0.5 or more, particularly preferably 0.9 or more, and is preferably 5 or less, more preferably 4 or less, even more preferably 3 or less, particularly preferably 2.5 or less. The molar ratio is particularly preferably 0.9 or more and 4 or less, and most preferably 0.9 or more and 2.5 or less.

[0035] Next, a 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 metal ions constituting the MOF with one or more organic compounds that serve as organic ligands constituting the MOF in a solvent. If necessary, it is also preferable to mix an inorganic compound that serves as an inorganic ligand with the metal compound or organic compound in the solvent.

[0036] Specifically, it is preferable to first prepare Solution A in which either a metal compound containing metal ions or an organic compound serving as an organic ligand is completely dissolved in a solvent, and then dropwise add the other (it is also preferable to dropwise add Solution B in which the other compound is also dissolved in a solvent at this time). Alternatively, it is preferable to prepare Solution X in which both a metal compound containing metal ions and an organic compound serving as an organic ligand are completely dissolved in a solvent, and then dropwise add a metal compound or organic compound of a different type from the metal compound and organic compound in Solution X, or to dropwise add Solution Y in which a metal compound or organic compound of a different type from the metal compound and organic compound in Solution X is completely dissolved in a solvent. The dropping temperature is preferably room temperature (specifically, about 20 to 30°C). The amount of the metal compound or organic compound to be dropped is preferably 1.0 mmol / min or less. The dropping rate is preferably 0.8 mmol / min or less, and may be 0.01 mmol / min or more, preferably 0.1 mmol / min or more, and more preferably 0.3 mmol / min or more. In particular, it is preferable to drop the metal compound or a solution in which the metal compound is dissolved in a solvent into a solution in which the organic compound is dissolved in a solvent, and it is more preferable to drop the metal compound at the above-mentioned dropping speed.

[0037] The metal compound containing the metal ion that constitutes the MOF is preferably a metal sulfate, nitrate, acetate, chloride, bromide or alkoxide.

[0038] The organic compounds that form the organic ligands of MOF are R(COOH) ｎ It is preferable that R and n contain one or more selected from the group consisting of polycarboxylic acids represented by the above R(COO － ) ｎThe above descriptions of R and n, including preferred embodiments, can all be referred to.

[0039] The organic compound serving as the organic ligand preferably contains a dicarboxylic acid or a tricarboxylic acid, and specific examples thereof include R(COO － ) ｎ The dicarboxylic acids or tricarboxylic acids described above for the carboxylates represented by the formula (I) can be referred to, including their preferred ranges.

[0040] As an organic compound that becomes an organic ligand, R(COOH) ｎ In addition to one or more selected from the group consisting of polycarboxylic acids represented by the formula (I), it is preferable to use 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. Furthermore, it is preferable to use an alkali metal hydroxide or an alkali metal azide as the inorganic compound serving as the inorganic ligand. Furthermore, OH groups may be present in the MOF due to the solvent that dissolves the metal compound or organic compound, moisture in the air, and the like. － , O ２－ , or OH ２ In some cases, the inorganic ligand is

[0041] The solvent for dissolving the metal compound containing a metal ion or the organic compound that serves as an organic ligand is preferably water; an alcohol solvent such as methanol or ethanol; or an amide solvent such as dimethylformamide, and one of these may be used alone or two or more of them may be mixed and used.

[0042] When preparing Solution A, Solution B, or Solution X in which a metal compound containing a metal ion is completely dissolved, the ratio of the metal compound to the solvent in each of these solutions (metal compound / solvent) is preferably 0.01 mol / L or more, more preferably 0.1 mol / L or more, even more preferably 0.18 mol / L or more, and preferably 1 mol / L or less, more preferably 0.7 mol / L or less, even more preferably 0.5 mol / L or less, and particularly preferably 0.370 mol / L or less. The ratio is particularly preferably 0.18 mol / L or more and 0.5 mol / L or less, and most preferably 0.18 mol / L or more and 0.370 mol / L or less.

[0043] When preparing solution A, solution B, or solution X in which an organic compound to be an organic ligand is completely dissolved, the ratio of the organic compound to the solvent in each of these solutions (organic compound / solvent) is preferably 0.01 mol / L or more, more preferably 0.1 mol / L or more, even more preferably 0.2 mol / L or more, and is preferably 1.5 mol / L or less, more preferably 1 mol / L or less, even more preferably 0.7 mol / L or less.

[0044] Furthermore, when an inorganic compound that serves as an inorganic ligand is contained in Solution A, Solution B, or Solution X, the ratio of the inorganic compound to the solvent in each of these solutions (inorganic compound / solvent) is preferably 0.05 mol / L or more and 1 mol / L or less.

[0045] The molar ratio of the metal compound containing the metal ion to the organic compound serving as the organic ligand may be adjusted so that the ratio of the molar amount of the metal atom in the metal compound to the molar amount of the organic compound is equal to the molar ratio of the metal ion to the organic ligand described above.

[0046] After the completion of the dropwise addition, it is important to perform at least one of refluxing, stirring, and standing at room temperature (for example, 25°C) to 200°C for about 5 minutes to 100 hours. More specifically, it is important to react the metal compound and the organic compound for 72 hours or more when the temperature is from room temperature to less than 100°C, 20 hours or more when the temperature is 100°C or more but less than 130°C, and 15 hours or more when the temperature is 130°C or more but less than 200°C. The resulting reaction product can be separated from the solvent by centrifugation or filtration, washed, and dried to obtain the desired MOF.

[0047] This application claims the benefit of 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.

[0048] The present invention will be described in more detail below with reference to examples. The present invention is not limited to the following examples, and can of course be practiced with appropriate modifications within the scope of the above and below-described aims, all of which are included in the technical scope of the present invention.

[0049] Example 1 In a 20 mL recovery flask, 3.233 mmol of isophthalic acid and 2.5 mL of dimethylformamide (DMF) were mixed at 25°C and completely dissolved to obtain solution A. ２ (SO ４ ) ３ ・nH ２ Solution B was prepared by mixing 3.693 mmol of O (n = 14 to 18) with 10 mL of ion-exchanged water to completely dissolve the compound, and the solution was added dropwise to solution A over 5 minutes at 25°C. In solution A, the ratio of isophthalic acid to the solvent was 1.29 mol / L, and in solution B, the ratio of Al to the solvent was 1.29 mol / L. ２ (SO ４ ) ３ ・nH ２ The ratio of O was 0.369 mol / L, and Al ２ (SO４ ) ３ ・nH ２ The dropwise addition rate of O was 0.739 mmol / min. The mixture was then refluxed at 125°C for 24 hours to obtain a suspension. The suspension was decanted, and the precipitated solid was washed three times with 10 ml of water by centrifugation. The resulting filter cake was dried in a vacuum oven at 80°C for 24 hours, 100°C for 24 hours, and 120°C for 48 hours to obtain 0.66 g of the product (yield: 99%).

[0050] Example 2 In a 100 mL recovery flask, 5.169 mmol of 1H-pyrrole-2,5-dicarboxylic acid, 13.5 mL of ion-exchanged water, and 10.42 mmol of sodium hydroxide were mixed at 25°C and completely dissolved to obtain solution A. ２ (SO ４ ) ３ ・nH ２ Solution B was prepared by mixing 2.555 mmol of 1H-pyrrole-2,5-dicarboxylic acid with 13.35 mL of ion-exchanged water to completely dissolve the compound, and the solution was added dropwise to solution A over 5 minutes at 25°C. In solution A, the ratio of 1H-pyrrole-2,5-dicarboxylic acid to the solvent was 0.383 mol / L, and in solution B, the ratio of Al to the solvent was 0.383 mol / L. ２ (SO ４ ) ３ ・nH ２ The ratio of O was 0.191 mol / L, and Al ２ (SO ４ ) ３ ・nH ２ The dropwise addition rate of O was 0.511 mmol / min. The mixture was then refluxed at 100°C for 24 hours to obtain a suspension. The suspension was decanted, and the precipitated solid was filtered and washed three times with 20 ml of water and three times with 20 ml of ethanol. The resulting filter cake was dried in a vacuum drying oven at 60°C for 24 hours to obtain 0.88 g of the product (yield 87%).

[0051] Example 3: In a 50 mL SUS-304 pressure vessel (including a Teflon (registered trademark) inner cylinder), 3.000 mmol of 2-aminoterephthalic acid was completely dissolved in 25 mL of a 1 / 1 (volume ratio) mixture of dimethylformamide (DMF) and MeOH to obtain Solution A. To this solution, 1.518 mmol of Ti[OCH(CH3)2]4 was added dropwise over 20 minutes at 25°C, and the mixture was stirred for 5 minutes with a stirrer tip. In Solution A, the ratio of 2-aminoterephthalic acid to solvent was 0.12 mol / L, and the dropwise addition rate of Ti[OCH(CH3)2]4 was 0.0759 mmol / min. The solution was then allowed to stand at 150°C for 16 hours. The obtained precipitated solid was washed three times with 10 mL of DMF and filtered, 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 (yield 89.4%).

[0052] Example 4: In a 50 mL vial, 2.496 mmol of terephthalic acid was added with 5 mL of DMF, and a stirrer tip was added and stirred to completely dissolve the acid, yielding Solution A. Separately, 2.654 mmol of indium(III) nitrate hydrate was added with 5 mL of dimethylformamide (DMF), followed by 2 mL of ethanol and a stirrer tip to completely dissolve the acid, yielding Solution B. Solution B was then added dropwise to Solution A over 20 minutes and stirred for 20 minutes. In Solution A, the ratio of terephthalic acid to the solvent was 0.499 mol / L, and in Solution B, the ratio of indium(III) nitrate hydrate to the solvent was 0.379 mol / L, and the dropwise addition rate of indium(III) nitrate hydrate was 0.133 mmol / min. The mixture was then allowed to stand at 120°C for 48 hours. The resulting precipitated solid was washed three times with 30 mL of DMF and filtered, and the resulting filter cake was dried under reduced pressure in a vacuum drying oven at 120° C. for 24 hours to obtain 0.49 g of the product (yield 89.1%).

[0053] Example 5: In a 1 L recovery flask, 3.05 mmol of cobalt(II) chloride hexahydrate, 10.42 mmol of 2,2'-dithiodibenzoic acid, 10.40 mmol of sodium azide, and 150 mL of DMF were mixed at 25°C and completely dissolved to obtain Solution A. Separately, 3.08 mmol of benzene tricarboxylate, 3.10 mmol of 4,4'-bipyridine, and 150 mL of ethanol were mixed and completely dissolved to prepare Solution B, which was then added dropwise to Solution A at 25°C over 3 hours. In Solution A, the ratio of cobalt(II) chloride hexahydrate to the solvent was 0.0203 mol / L, and the ratio of 2,2'-dithiodibenzoic acid to the solvent was 0.0695 mol / L. In Solution B, the ratio of the combined amount of benzene tricarboxylate and 4,4'-bipyridine to the solvent was 0.0412 mol / L. The dropwise addition rate of the total amount of tricarboxylic acid benzene and 4,4'-bipyridine was 0.0343 mmol / min. The mixture was then stirred at 25°C for 4 days to obtain a suspension. The obtained precipitated solid was washed three times with 30 mL of DMF and filtered. The obtained filter cake was dried under reduced pressure at 120°C for 24 hours in a vacuum drying oven to obtain 1.16 g of the product (yield: 90.0%).

[0054] Example 6 In a 100 mL SUS-304 pressure vessel (including a Teflon (registered trademark) inner cylinder), 7.483 mmol of terephthalic acid was completely dissolved in 25 mL of a 9 / 1 (volume ratio) mixture of dimethylformamide (DMF) and MeOH to obtain Solution A. This Solution A was dissolved in 4.523 mmol of Ti[OCH(CH ３ ) ２ ] ４ The mixture was added dropwise to the solvent at 25°C over 30 minutes, followed by stirring with a stirrer tip for 5 minutes. The ratio of terephthalic acid to the solvent in Solution A was 0.299 mol / L, and the dropwise addition rate of terephthalic acid was 0.249 mmol / min. The mixture was then allowed to stand at 150°C for 16 hours. The resulting precipitated solid was washed and filtered three times with 10 mL of DMF, and the resulting filter cake was dried under reduced pressure in a vacuum oven at 120°C for 24 hours and 150°C for 24 hours, yielding 0.35 g of the product (yield: 24.6%).

[0055] Comparative Example 1: A 500 mL recovery flask was charged with formic acid (2.69 mol), acetic anhydride (1.08 mol), and Ti(OCH(CH ３ ) ２ ) ４ (0.067 mol) was added, and the mixture was stirred at 25°C for 30 minutes. The mixture was then heated to 120°C and refluxed for 12 hours. The resulting cloudy reaction solution was washed with acetone (100 ml x 3 times) while heated to 50°C, yielding 12.03 g of white solid A (yield: 74.8%). In a 500 mL SUS-304 pressure vessel (including a Teflon (registered trademark) inner cylinder), 0.23 mmol of white solid A was dissolved in a mixture of acetic anhydride (10 mL) and acetic acid (10 mL). 55.2 mmol of 5-aminoisophthalic acid was added all at once, and then 1 mL of methanol was added at 25°C. The mixture was stirred for 5 minutes with a stirrer tip. The mixture was then allowed to stand at 180°C for 48 hours. The resulting precipitated solid was washed three times with 30 mL of acetone and filtered, and the resulting filter cake was air-dried for 24 hours to obtain 0.20 g of the product (yield: 47.9%).

[0056] Comparative Example 2 In a 50 mL recovery flask, 2.54 mmol of 2,5-thiophenedicarboxylic acid and 4 mL of DMF were mixed at 25°C and completely dissolved to obtain solution A. ２ (SO ４ ) ３ ・nH ２ Solution B was prepared by mixing 5.64 mmol of O (n = 14-18) with 16 mL of ion-exchanged water to completely dissolve the compound, and solution B was added to solution A all at once at 25°C. The mixture was then refluxed with stirring at 135°C for 24 hours to obtain a suspension. The resulting precipitated solid was washed three times with 30 mL of DMF and three times with 30 mL of methanol, and then filtered. The resulting filter cake was dried under reduced pressure at 80°C for 24 hours in a vacuum oven to obtain 0.65 g of the product (yield: 48.2%).

[0057] Comparative Example 3 In a 100 mL SUS-304 pressure vessel (including a Teflon (registered trademark) inner tube), 5.1 mmol of AlCl3, 2.089 mmol of terephthalic acid, and 60 mL of DMF were mixed all at once and dissolved by applying ultrasound at room temperature for 5 minutes. The mixture was then allowed to stand at 110°C for 20 hours. The resulting precipitated solid was washed and filtered three times with 30 mL of DMF, and the resulting filter cake was dried under reduced pressure in a vacuum drying oven at 60°C for 30 minutes and 150°C for 12 hours, yielding 0.38 g of the product (yield 90%).

[0058] Comparative Example 4 In a 50 mL recovery 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. ３ ・6H ２ Solution B was prepared by mixing 2,5-furandicarboxylic acid and 10 mL of ion-exchanged water to completely dissolve the 2,5-furandicarboxylic acid in the solvent, and the solution was added dropwise to solution A over 30 minutes at 25°C. 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 AlCl to the solvent was 0.336 mol / L. ３ ・6H ２ The ratio of AlCl ３ ・6H ２ The dropwise addition rate of O was 0.168 mmol / min. The mixture was then refluxed at 25°C for 18 hours to obtain a suspension. The resulting precipitated solid was washed three times with 50 mL of water by centrifugation, and the resulting cake was dried in a vacuum drying oven at 80°C for 24 hours to obtain a product material.

[0059] The substances obtained in the examples and comparative examples were evaluated by the following methods.

[0060] (1) Measurement of porosity The materials produced in the examples and comparative examples were subjected to XRD measurement under the following conditions, a cif file was obtained, and the cif file was read using software called Mercury. The void contact surface probe radius of 1.5 Å and approximate grid spacing of 0.7 Å were input into the obtained data to determine the porosity. Apparatus: SmartLab manufactured by Rigaku Corporation; Radiation source: Cu; Measurement range: 2θ = 3 to 40°; Step size: 0.01°; Scanning speed: 3° / min; Measurement temperature: room temperature (25°C).

[0061] (2) Measurement of Maximum Pore Diameter L and Minimum Pore Diameter S From the Mercury diagram obtained during the measurement of the porosity, a crystal structure including pore size and pore shape was obtained, and the maximum pore diameter L and minimum pore diameter S were determined according to the above-described procedures (a1) to (a3).

[0062] (3) Measurement of desorption amount Using a thermogravimetry-differential thermal analysis (TG-DTA) device manufactured by Rigaku Corporation, the amount of desorption of water from MOFs pretreated under the following conditions was measured. Pretreatment conditions: 25°C, held for 12 hours in an air atmosphere conditioned at a relative pressure of 0.5. Desorption amount: After the pretreatment described above, the temperature was increased at a rate of 5°C / min under a nitrogen flow and held at 50°C for 30 minutes. The weight loss W in this section (25 to 50°C) was ２５－５０ Measure this W ２５－５０ was divided by the weight of the sample after the pretreatment to obtain the amount of desorption (mass %).

[0063] The results are shown in Table 1. In Comparative Example 1, the pores observed in the cross-sectional observation in step (a2) were not through-pores, and therefore "closed" was entered in the maximum pore diameter L / minimum pore diameter S column.

[0064]

[0065] In Examples 1 to 6, crystalline MOFs were obtained in which the porosity was 20 to 75% and the ratio of maximum pore size L to minimum pore size S was 1.06 or more. However, the MOFs of Comparative Examples 1 to 3 did not satisfy at least one of the requirements of maximum pore size L to minimum pore size and porosity. In Comparative Example 4, the reflux conditions after dropwise addition of Solution B to Solution A were not appropriate, and therefore, no crystalline substance was confirmed by XRD measurement.

[0066] The MOF of the present invention is suitable for use in the adsorption and removal of, for example, gases and organic molecules. Examples of gases include water (water vapor), carbon dioxide, hydrogen, carbon monoxide, oxygen, nitrogen, hydrocarbons having 1 to 4 carbon atoms, rare gases, hydrogen sulfide, ammonia, sulfur oxides, nitrogen oxides, and siloxanes. Examples of organic molecules 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, and amides having 1 to 8 carbon atoms. The organic molecules may contain an aromatic ring.

[0067] 11 inscribed circle 21 cross section 22 through hole P ｍａｘ 23a, 23b through hole P ｍａｘ Outer periphery 24 Through hole P ｍａｘ Central axis 25 Maximum hole diameter L 26 Minimum hole diameter S

Claims

1. A metal-organic structure composed of an organic ligand and a metal ion, The porosity is 20-75%, 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 the following procedure (a1) to (a3), is 1.06 or greater. The aforementioned organic ligand is R(COO-) ｎ Here, R is an aromatic hydrocarbon group or pyrrole, -OH, -NH ２ Alternatively, it may have a functional group X which is -S-S-, and it comprises at least one organic ligand where n is 2 or more and 3 or less. The metal-organic structure is a metal ion selected from the group consisting of Al, Ga, In, Ti, V, Cr, Mn, Fe, Co, Cu, Zr, and Hf. (a1) The crystal structure determined by X-ray crystallography is displayed using a space-filling model, ensuring that the outer circumference of the through-hole is not missing, and the presence or absence of the through-hole is observed from all directions. The through-hole P is the one with the largest diameter of the inscribed circle. ｍａｘ Identify. (a2) The through hole P ｍａｘ In the cross sections ab, bc, and ca, the through hole P ｍａｘ A through hole P cut by a line perpendicular to the central axis. ｍａｘ Find the maximum length of the inner diameter, and among the maximum lengths of cross sections ab, bc, and ca, find the maximum length of the through hole P. ｍａｘ Let L be the maximum pore diameter. However, the cross-section ab is the cut surface of the through-hole P on a plane parallel to the a-b plane of the unit cell, and is the surface cut out in a state where the through-hole P has penetrated. When there are a plurality of cross-sections through which the through-hole P can be cut out in a penetrated state, the cross-section with the largest overlap with the through-hole P is referred to as the cross-section ab. Also, in specifying the cross-section ab, the one obtained by reading the cross-section ab as the cross-section bc and reading the a-b plane as the b-c plane is the cross-section bc, and the one obtained by reading the cross-section ab as the cross-section ca and reading the a-b plane as the c-a plane is the cross-section ca. ｍａｘ is the cut surface of ｍａｘ and is the surface cut out in a state where the through-hole P ｍａｘ has penetrated. When there are a plurality of cross-sections through which the through-hole P ｍａｘ can be cut out in a penetrated state, the cross-section with the largest overlap with the through-hole P is referred to as the cross-section ab. Also, in specifying the cross-section ab, the one obtained by reading the cross-section ab as the cross-section bc and reading the a-b plane as the b-c plane is the cross-section bc, and the one obtained by reading the cross-section ab as the cross-section ca and reading the a-b plane as the c-a plane is the cross-section ca. (a3) In the cross section in which the maximum hole diameter L was determined, through hole P ｍａｘ A through hole P cut by a line perpendicular to the central axis. ｍａｘ The minimum length of the inner diameter is defined as the minimum hole diameter S.

2. The metal-organic structure according to claim 1, wherein the ratio of the maximum pore diameter L to the minimum pore diameter S (maximum pore diameter L / minimum pore diameter S) is 4.0 or less.

3. The metal-organic structure according to Claim 1, wherein the organic ligand is represented as R(COO-)n (where n is 2 or more and 3 or less), and R is a group that is one of the following (A-1) to (A-10). 【Chemistry 1】 In (A-1) to (A-10) above, at least one hydrogen atom bonded to a carbon atom may be substituted with -OH or -NH2, and -X- represents -S-S- or a single bond.

4. The metal-organic structure according to claim 1, wherein the metal ion is an ion of at least one metal selected from the group consisting of Al, Ga, In, Ti, V, Co, Zr, and Hf.

5. The metal-organic structure according to claim 1, wherein the molar ratio of the metal ion to the organic ligand (metal ion / organic ligand) is 0.1 or more and 5 or less.

6. The metal-organic structure according to claim 1, wherein the porosity is 25% or more and 70% or less.

7. The metal-organic structure according to claim 1, wherein the maximum pore diameter L is 2.5 to 20 Å and the minimum pore diameter S is 1.5 to 15 Å.

8. A metal-organic structure obtained by first completely dissolving in a solvent either a metal compound containing a metal ion constituting the metal-organic structure or an organic compound that serves as an organic ligand constituting the metal-organic structure either in a solution A, and then dropping the other or a solution B in which the other is dissolved in the solvent, or by preparing a solution X in which both the metal compound and the organic compound are completely dissolved in a solvent, and then dropping a metal compound or organic compound of a different type from the metal compound and organic compound in solution X, or by dropping a solution Y in which a metal compound or organic compound of a different type from the metal compound and organic compound in solution X is completely dissolved in the solvent, A metal-organic structure in which the amount of metal compound or organic compound added dropwise is 1.0 mmol / min or less.

9. The metal-organic structure according to claim 8, obtained by reacting the metal compound and the organic compound for 72 hours or more at room temperature or below 100°C, or for 20 hours or more at 100°C or above but below 130°C, or for 15 hours or more at 130°C or above but below 200°C, after the dropwise addition is complete.

10. A method for manufacturing a metal-organic structure, First, prepare solution A by completely dissolving either a metal compound containing metal ions constituting a metal-organic structure or an organic compound that serves as an organic ligand constituting a metal-organic structure in a solvent, and then dropwise add the other, or solution B in which the other is completely dissolved in the solvent, or prepare solution X in which both the metal compound and the organic compound are completely dissolved in the solvent, and then dropwise add a metal compound or organic compound of a different type from the metal compound and organic compound in solution X, or dropwise add solution Y in which a metal compound or organic compound of a different type from the metal compound and organic compound in solution X is completely dissolved in the solvent. A method for producing a metal-organic structure, wherein the amount of metal compound or organic compound added dropwise is 1.0 mmol / min or less.

11. A method for producing a metal-organic structure according to claim 10, wherein, after the dropping is completed, the metal compound and the organic compound are reacted at room temperature or below 100°C for 72 hours or more, or at 100°C or above but below 130°C for 20 hours or more, or at 130°C or above but below 200°C for 15 hours or more.

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