Metal-organic structures, gas storage agents containing the same, and gas storage methods using the same

Abstract

The present invention addresses the problem of providing: a novel metal organic structure having gas storage capability; and a gas-storing agent and a gas storage method, in each of which the metal organic structure is used.　Provided is a metal organic structure in which a carboxylic acid ion represented by formula (1) is bound to a polyvalent metal ion (provided that a metal organic structure in which a carboxylic acid ion represented by formula (1) is bound to a bivalent copper ion in which X in formula (1) represents a sulfur atom, each of m1, m2, n1 and n2 represents 0, and both COO-'s are respectively bound to position-2 and position-8 is excluded). (In formula (1), X represents a sulfur atom or an oxygen atom; R1represents a hydroxy group, a C1-6 alkyl group, a C1-6 alkoxy group, or a halogeno group; n1 and n2 independently represent any one integer of 0 to 3; when there are two or more R1's, the R1's may be the same as or different from each other; m1 and m2 independently represent 0 or 1; and when there are two or more L's, the L's may be the same as or different from each other.)

Description

[Technical Field]

[0001] The present invention relates to a metal-organic structure formed by the bonding of a carboxylic acid ion and a polyvalent metal ion, a gas storage agent containing the metal-organic structure, and a gas storage method comprising the step of contacting the metal-organic structure with a gas. This application claims priority to Japanese Patent Application No. 2021-091175, filed on 31 May 2021, the contents of which are incorporated herein by reference. [Background technology]

[0002] Metal-organic structures (hereinafter sometimes referred to as "MOFs") are solid materials that have a polymeric structure with internal spaces (i.e., pores) formed by combining metal ions with cross-linking organic ligands that connect them. They have attracted considerable interest over the past decade or so as porous materials with functions such as gas storage and separation. For example, a material with a surface area of ​​4000 m² obtained by heating zirconium chloride and terphenyldicarboxylic acid in dimethylformamide... 2 It is known that MOFs at a concentration of / g can store gases such as hydrogen, methane, and acetylene (see Patent Document 1). Furthermore, it is known that MOFs can be obtained as dark brown crystals by heating a dicarboxylic acid represented by the following formula and Fe2CoO(CH3COO)6 or Fe3O(CH3COO)6 in the presence of acetic acid in N-methylpyrrolidone at 150°C for 24 hours, and that these MOFs can store gases such as hydrogen, methane, carbon dioxide, and nitrogen (see Patent Document 2).

[0003] [ka]

[0004] Furthermore, Patent Document 2 discloses a metal-organic structure in which a dicarboxylic acid ion obtained from a dicarboxylic acid represented by the following formula is bonded to Fe.

[0005] [ka]

[0006] In the course of such development, it is known that the structure of metal-organic frameworks varies significantly depending on the type of metal used, the ligand, and the reaction conditions, and there is a further demand for the development of novel metal-organic frameworks having a gas storage function.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0008] An object of the present invention is to provide a novel metal-organic framework having a gas storage function, a gas storage agent using the same, and a gas storage method.

Means for Solving the Problems

[0009] As a result of intensive studies to solve the above problems, the present inventors have found a novel metal-organic framework obtained by using a specific dicarboxylic acid having a dibenzothiophene skeleton or a dibenzofuran skeleton as an organic ligand. In addition, it has been found that these novel metal-organic frameworks have a high hydrogen storage capacity, leading to the completion of the present invention.

[0010] That is, the present invention is specified by the following matters. (1) A metal-organic framework formed by bonding a carboxylic acid ion represented by formula (1) and a polyvalent metal ion (however, a metal-organic framework formed by bonding a carboxylic acid ion represented by formula (1) and a divalent copper ion, wherein X in formula (1) is a sulfur atom, m1, m2, n1, and n2 are all 0, and COO - excluding those in which both are bonded to the 2-position and the 8-position). [Chemical formula] (In formula (1), X is a sulfur atom or an oxygen atom. R 1 is a hydroxy group, a C1-6 alkyl group, a C1-6 alkoxy group, or a halogeno group. n1 and n2 are each an integer of 0 to 3. When there are two or more Rs 1 they may be the same as or different from each other. 1 L is a divalent group represented by the following formula (2). m1 and m2 are each 0 or 1. When there are two or more Ls, they may be the same as or different from each other. [Chemical formula] In formula (2), R 2 is a hydroxy group, a C1-6 alkyl group, a C1-6 alkoxy group, or a halogeno group. n3 is an integer of 0 to 4. When there are two or more Rs 2 they may be the same as or different from each other. 2 * and ** represent bonding positions, and ** represents the bonding position with the carboxylic acid ion.) (2) The metal-organic structure according to (1) above, wherein the polyvalent metal ion is at least one metal ion selected from the group consisting of metals of Groups 2 to 13 of the periodic table of the elements. (3) The metal-organic structure according to (1) or (2) above, further comprising an auxiliary ligand as a constituent component. (4) A gas storage agent containing the metal-organic structure according to any one of (上述の) (1) to (3). (5) A gas storage method including a step of bringing a gas into contact with the metal-organic structure according to any one of (上述の) (1) to (3). [Advantages of the Invention]

[0011] The metal-organic structure of the present invention is novel and can store gases such as hydrogen, carbon dioxide, and nitrogen.

Mode for Carrying Out the Invention

[0012] The metal-organic structure of the present invention is a metal-organic structure formed by the bonding of a carboxylic acid ion represented by formula (1) and a polyvalent metal ion (however, it is a metal-organic structure formed by the bonding of a carboxylic acid ion represented by formula (1) and a divalent copper ion, where X in formula (1) is a sulfur atom, m1, m2, n1, and n2 are all 0, and COO - is excluded from those in which both are bonded to the 2nd and 8th positions).

[0013]

Chemical formula

[0014] In formula (1), X is a sulfur atom or an oxygen atom. R 1 is a hydroxy group, a C1-6 alkyl group, a C1-6 alkoxy group, or a halogeno group. n1 and n_{2} indicate the number of R 1 and are any integer from 0 to 3. When there are two or more R 1 ]], each R 1 may be the same as or different from each other. L is a divalent group represented by the following formula (2). m1 and m2 indicate the number of L and are 0 or 1. When there are two or more L, each L may be the same as or different from each other.

[0015]

Chemical formula

[0016] R 1 Examples of the C1-6 alkyl group of R 1 can be linear or branched, and include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an n-pentyl group, an n-hexyl group, an i-propyl group, an i-butyl group, an s-butyl group, a t-butyl group, an i-pentyl group, a neopentyl group, a 2-methyl-n-butyl group, an i-hexyl group, etc. R 1Examples of C1-6 alkoxy groups include methoxy group, ethoxy group, n-propoxy group, i-propoxy group, n-butoxy group, s-butoxy group, i-butoxy group, t-butoxy group, etc. 1 Examples of halogen groups include fluoro groups, chloro groups, bromo groups, and iod groups.

[0017] In formula (2), R 2 n3 is R 2 This indicates the number, which is an integer between 0 and 4. 2 When R is 2 or greater, each R 2 They may be the same or different from each other. 2 The C1-6 alkyl group may be linear or branched, and examples include methyl group, ethyl group, n-propyl group, n-butyl group, n-pentyl group, n-hexyl group, i-propyl group, i-butyl group, s-butyl group, t-butyl group, i-pentyl group, neopentyl group, 2-methyl-n-butyl group, i-hexyl group, etc. 2 Examples of C1-6 alkoxy groups include methoxy group, ethoxy group, n-propoxy group, i-propoxy group, n-butoxy group, s-butoxy group, i-butoxy group, t-butoxy group, etc. 2 Examples of halogen groups include fluoro, chloro, bromo, and iod groups. * and ** indicate the bonding position, and ** indicates the bonding position with the carboxylate ion. Terms such as "C1-6" indicate that the parent group has 1 to 6 carbon atoms, etc. Specific examples of carboxylic acid ions represented by formula (1) include the compounds shown in the following formulas. While the following formulas illustrate the case where X is S, similar structures can be illustrated when X is O.

[0018] [ka] TIFF0007839512000008.tif255170

[0019] The polyvalent metal ions in the metal-organic structure of the present invention are not particularly limited as long as they are ions of metals with a valency of 2 or higher, but at least one metal ion selected from the group consisting of metals from Group 2 to Group 13 of the periodic table is preferred, and at least one metal ion selected from Zn, Al, Cu, Zr, Ni, Co, Cr, Fe, Sc, Mo, Mn, Ti, and Mg is more preferred. In the metal-organic structure of the present invention, the polyvalent metal ions that bond with the carboxylate ion represented by formula (1) may be one or two or more.

[0020] These polyvalent metal ions are supplied in the form of various salts. Specifically, these metal salts include zinc nitrate (Zn(NO3)2·xH2O), titanium nitrate (Ti(NO3)4·xH2O), cobalt nitrate (Co(NO3)2·xH2O), iron(III) nitrate (Fe(NO3)3·xH2O), iron(II) nitrate (Fe(NO3)2·xH2O), nickel(II) nitrate (Ni(NO3)2·xH2O), copper(II) nitrate (Cu(NO3)2·xH2O), aluminum(III) nitrate (Al(CH3COO)3·xH2O), magnesium(II) nitrate (Mg(NO3)2·xH2O); zinc chloride (ZnCl2·x H2O), titanium chloride (TiCl4·xH2O), zirconium chloride (ZrCl4·xH2O), cobalt chloride (CoCl2·xH2O), iron(III) chloride (FeCl3·xH2O), iron(II) chloride (FeCl2·xH2O), chromium(III) chloride (CrCl3·xH2O), scandium(III) chloride (ScCl3·xH2O), manganese(II) chloride (MnCl2·xH2O); zinc acetate (Zn(CH3COO)2·xH2O), titanium acetate (Ti(CH3COO)4·xH2O), zirconium acetate (Zr(CH3COO)4·xH2O) (xH2O), cobalt acetate (Co(CH3COO)2·xH2O), iron(III) acetate (Fe(CH3COO)3·xH2O), iron(II) acetate (Fe(CH3COO)2·xH2O); zinc sulfate (ZnSO4·xH2O), titanium sulfate (Ti(SO4)2·xH2O), zirconium sulfate (Zr(SO4)2·xH2O), cobalt sulfate (CoSO4·xH2O), iron(III) sulfate (Fe2(SO4)3·xH2O), iron(II) sulfate (FeSO4·xH2O), magnesium(II) sulfate (MgSO4·xH2O); zinc hydroxide (Z n(OH)₂·xH₂O), titanium hydroxide (Ti(OH)₄·xH₂O), zirconium hydroxide (Zr(OH)₄·xH₂O), cobalt hydroxide (Co(OH)₂·xH₂O), iron(III) hydroxide (Fe(OH)₃·xH₂O), iron(II) hydroxide (Fe(OH)₂·xH₂O); zinc bromide (ZnBr₂·xH₂O), titanium bromide (TiBr₄·xH₂O), zirconium bromide (ZrBr₄·xH₂O), cobalt bromide (CoBr₂·xH₂O), iron(III) bromide (FeBr₃·xH₂O), iron(II) bromide (FeBr₂·xH₂O);Examples include zinc carbonate (ZnCO3·xH2O), cobalt carbonate (CoCO3·xH2O), iron(III) carbonate (Fe2(CO3)3·xH2O); zirconium chloride oxide (ZrOCl2·xH2O); and molybdenum(II) acetate dimer ((Mo(CH3COO)2)2). Note that x is a number from 0 to 12. These can be used individually or in mixtures of two or more.

[0021] The metal-organic structure of the present invention may contain organic ligands other than the carboxylate ion represented by formula (1) as auxiliary ligands. By incorporating auxiliary ligands into the metal-organic structure, a higher-order structure can be introduced into the metal-organic structure. Such auxiliary ligands include terephthalic acid, phthalic acid, isophthalic acid, 5-cyanoisophthalic acid, 1,3,5-trimesic acid, 1,3,5-tris(4-carboxyphenyl)benzene, 4,4'-dicarboxybiphenyl, 3,5-dicarboxypyridine, 2,3-dicarboxypyrazine, 1,3,5-tris(4-carboxyphenyl)benzene, 1,2,4,5-tetrakis(4-carboxyphenyl)benzene, 9,10-anthracenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, [1,1':4',1”]terphenyl-3,3”,5,5”-tetracarboxylic acid, biphenyl-3,3”,5,5”-tetracarboxylic acid, 3,3',5,5'-tetracarboxydiphenylmethane, 1,3,5-tris(4'-carboxy[1,1'-biphenyl Examples include [4-yl]benzene, 1,3,5-tris(4-carboxyphenyl)triazine, 1,2-bis(4-carboxy-3-nitrophenyl)ethene, 1,2-bis(4-carboxy-3-aminophenyl)ethene, trans,trans-muconic acid, fumaric acid, benzimidazole, imidazole, 1,4-diazabicyclo[2.2.2]octane (DABCO), pyrazine, 4,4'-dipyridyl, 1,2-di(4-pyridyl)ethylene, 1,2-di(4-pyridyl)ethane, 2,7-diazapyrene, 4,4'-azobispyridine, 1,5-naphthyridine, phenazine, and 2-bis(3-(4-pyridyl)-2,4-pentanedionato)copper. The molar ratio of the mixture when using the carboxylate ion represented by formula (1) and the auxiliary ligand is not particularly limited.

[0022] The present invention is not particularly limited as a method for producing the metal-organic structure, and any of the following methods can be used: solution methods such as solvent diffusion, solvent stirring, and hydrothermal methods; microwave methods in which microwaves are irradiated onto the reaction solution to uniformly heat the entire system in a short time; ultrasonic methods in which ultrasonic waves are irradiated onto the reaction vessel to repeatedly cause pressure changes in the reaction vessel, and this pressure change causes a phenomenon called cavitation in which the solvent forms bubbles and collapses, at which time a high-energy field of about 5000K and 10000 bar is locally formed, which serves as the reaction field for the formation of each crystal; solid-phase synthesis methods in which a metal ion source and an organic ligand are mixed without using a solvent; and LAG (liquid-assisted grinding) methods in which water in the amount of crystal water is added and the metal ion source and the organic ligand are mixed.

[0023] For example, the process includes the steps of preparing a first solution containing a metal compound that serves as a source of metal ions and a solvent, a second solution containing a carboxylic acid ion represented by formula (1) or its precursor and a solvent, and, if necessary, a third solution containing an auxiliary ligand and a solvent, and the steps of preparing a reaction solution by mixing the first solution, the second solution and the third solution, and heating this reaction solution to obtain a metal-organic structure. The first to third solutions do not need to be prepared separately; for example, the metal compound, the carboxylic acid ion represented by formula (1) or its precursor, the compound that serves as the auxiliary ligand and the solvent may be mixed at once to prepare a single solution.

[0024] The molar ratio of the above-mentioned metal compound to the carboxylic acid ion represented by formula (1) or its precursor carboxylic acid can be arbitrarily selected depending on the pore size and surface properties of the resulting metal-organic structure. However, it is preferable to use 1 mole or more of the metal compound per 1 mole of the carboxylic acid ion represented by formula (1) or its precursor carboxylic acid, and it is even more preferable to use 1.1 moles or more, 1.2 moles or more, 1.5 moles or more, 2 moles or more, and 3 moles or more.

[0025] The concentration of the above metal ions in the reaction solution is preferably in the range of 25 to 200 mmol / L. The concentration of the carboxylic acid ion represented by formula (1) or its precursor carboxylic acid in the reaction solution is preferably in the range of 10 to 100 mmol / L. The concentration of the auxiliary ligand in the reaction solution is preferably 10 to 100 mmol / L.

[0026] The solvent used is not particularly limited, but one or more solvents selected from the group consisting of N,N-dimethylformamide (hereinafter sometimes referred to as "DMF"), N,N-diethylformamide (hereinafter sometimes referred to as "DEF"), N,N-dimethylacetamide (hereinafter sometimes referred to as "DMA"), N-methyl-2-pyrrolidone (hereinafter sometimes referred to as "NMP"), dimethyl sulfoxide (hereinafter sometimes referred to as "DMSO"), and water can be used in mixtures. In addition, alcohols such as methyl alcohol and ethyl alcohol may be mixed with these solvents.

[0027] The heating temperature of the reaction solution is not particularly limited, but examples include ranges such as room temperature to 140°C, 70 to 140°C, and 80 to 120°C.

[0028] The gas storage agent of the present invention comprises the metal-organic structure of the present invention. The gas storage agent of the present invention may consist only of the metal-organic structure of the present invention, or it may contain other components to the extent that it does not hinder its use as a gas storage agent. The shape of the gas storage agent of the present invention is not particularly limited, and examples include powder, granules, pellets, etc. The metal-organic structure of the present invention can store gases such as hydrogen, methane, acetylene, carbon dioxide, nitrogen, etc., by adsorbing or storing the said gases. The method of storing gas using the metal-organic structure of the present invention is not particularly limited, but a method of bringing the metal-organic structure of the present invention into contact with the gas is preferred, and the method of contact is not particularly limited. For example, examples include filling a tank with the metal-organic structure of the present invention to make a gas storage tank and introducing the gas into the tank, supporting the metal-organic structure of the present invention on the surface constituting the inner wall of a tank to make a gas storage tank and introducing the gas into the tank, and molding a tank from a material containing the metal-organic structure of the present invention to make a gas storage tank and introducing the gas into the tank. [Examples]

[0029] The present invention will be specifically described below with reference to examples of the present invention, but the technical scope of the present invention is not limited to these examples. Organic ligands 1 to 9 shown in Table 1 below were used as carboxylic acids that serve as precursors to the carboxylic acid ion represented by formula (1) that constitutes the metal-organic structure of the present invention.

[0030] [Table 1]

[0031] When auxiliary ligands were included, the auxiliary ligands used were those shown in Table 2, namely Auxiliary Ligands 1 to 10.

[0032] [Table 2]

[0033] [Production Example 1] Synthesis of Organic Ligand 1 Dibenzothiophene (5.43 mmol) was dissolved in 20 mL of acetic acid, and a solution of bromine (11.0 mmol) in acetic acid (5 mL) was added dropwise over 30 minutes or more. The reaction solution was stirred at room temperature for 2 hours, and then stirred at 130°C for 5 hours. The reaction solution was allowed to return to room temperature, and the precipitated solid was filtered. The obtained solid was washed with water, and recrystallization with acetic anhydride yielded a colorless solid. The obtained solid was washed with water to obtain 2.00 mmol of 2,8-dibromodibenzothiophene as a colorless solid. The obtained 2,8-dibromodibenzothiophene (10.0 mmol) was dissolved in 100 mL of tetrahydrofuran and cooled to -78°C. 19.1 mmol of n-butyllithium hexane solution (1.57 M) was added dropwise to the cooled reaction solution over 30 minutes, and the mixture was stirred at low temperature for 2 hours. After stirring, finely crushed dry ice was added and the mixture was stirred for 1 hour. After further stirring at room temperature for 1 hour, tetrahydrofuran was removed by distillation, and then concentrated hydrochloric acid was added. The precipitated solid was filtered, washed with water and methanol, and then dried at 100°C to obtain 8.12 mmol of 2,8-dicarboxydibenzothiophene (organic ligand 1) as a colorless solid.

[0034] [Production Example 2] Synthesis of Organic Ligand 2 Except for using dibenzofuran instead of dibenzothiophene as in Production Example 1, the same procedure was followed to obtain organic ligand 2 as a colorless solid.

[0035] [Production Example 3] Synthesis of Organic Ligand 3 2,8-Dibromodibenzothiophene (3.31 mmol), potassium carbonate (16.5 mmol), 4-methoxycarbonylphenylboronic acid (8.26 mmol), tetrakis(triphenylphosphine)palladium (0.165 mmol), 20 mL of 1,2-diethoxyethane, and 6 mL of water were stirred at 100°C for 2 days. After returning to room temperature, water was added, and the organic layer extracted with chloroform was dried over magnesium sulfate and filtered. The filtrate was distilled under reduced pressure. Separation and purification by silica gel column chromatography yielded 0.877 mmol of 2,8-bis(4-methoxycarbonylphenyl)dibenzothiophene as a white solid. To the obtained 2,8-bis(4-methoxycarbonylphenyl)dibenzothiophene (0.877 mmol), potassium hydroxide (4.39 mmol), 20 mL of methanol, 20 mL of water, and 20 mL of tetrahydrofuran were added, and the mixture was stirred overnight at 90°C. The solution was returned to room temperature, dilute hydrochloric acid was added, the precipitated solid was filtered, and the mixture was thoroughly washed with water and dried to obtain 0.877 mmol of 2,8-bis(4-carboxyphenyl)dibenzothiophene (organic ligand 3) as a colorless solid.

[0036] [Production Example 4] Synthesis of Organic Ligand 4 2,8-Dibromodibenzothiophene (3.31 mmol), copper(I) iodide (0.331 mmol), triphenylphosphine (0.661 mmol), bis(triphenylphosphine)palladium dichloride (0.661 mmol), 4-methoxycarbonylphenylacetylene (9.92 mmol), and 30 mL of triethylamine were stirred at 120°C for 2 days. After returning to room temperature, water was added, and the organic layer extracted with dichloromethane was dried over magnesium sulfate and filtered. The filtrate was distilled under reduced pressure. Separation and purification by silica gel column chromatography yielded 2.30 mmol of 2,8-bis(4-methoxycarbonylphenylethynyl)dibenzothiophene as a white solid. To the obtained 2.00 mmol of 2,8-bis(4-methoxycarbonylphenylethynyl)dibenzothiophene, potassium hydroxide (10.0 mmol), methanol (30 mL), water (30 mL), and tetrahydrofuran (30 mL) were added and the mixture was stirred overnight at 90°C. After returning to room temperature, dilute hydrochloric acid was added, the precipitated solid was filtered, washed thoroughly with water, and dried to obtain 1.50 mmol of 2,8-bis(4-carboxyphenylethynyl)dibenzothiophene (organic ligand 4) as a colorless solid.

[0037] [Production Example 5] Synthesis of Organic Ligand 5 The same procedure as in Production Example 4 was followed, except that 2,8-dibromodibenzofuran was used instead of 2,8-dibromodibenzothiophene, to obtain organic ligand 5 as a colorless solid.

[0038] [Production Example 6] Synthesis of Organic Ligand 6 Dibenzothiophene (5.43 mmol) was dissolved in acetic acid (14 mL), and hydrogen peroxide (2.44 mL) was added dropwise. The reaction solution was stirred at 130°C for 4 hours. After returning to room temperature, the reaction solution was poured into water, and a colorless solid precipitated. The resulting suspension was filtered, and the colorless solid was thoroughly washed with water and methanol and dried to obtain 5.09 mmol of dibenzothiophene dioxide as a colorless solid. The obtained 4.62 mmol of dibenzothiophene dioxide and N-bromosuccinimide (9.24 mmol) were dissolved in sulfuric acid (150 mL) and stirred at room temperature for 24 hours. The resulting suspension was slowly poured into ice water, the suspension was filtered, and the colorless solid was thoroughly washed with water and methanol and dried to obtain 3.45 mmol of 3,7-dibromodibenzothiophene dioxide as a colorless solid. To the resulting 2.63 mmol suspension of 3,7-dibromodibenzothiophene dioxide in diethyl ether (40 mL), lithium aluminum hydride (10.4 mmol) was added, and the mixture was heated and stirred at 50°C for 1 hour. The resulting suspension was poured into ice water and acidified with hydrochloric acid. The reaction solution was extracted with chloroform, the organic layer was dried over magnesium sulfate, filtered, and the filtrate was distilled under reduced pressure. The resulting crude product was recrystallized with acetone to obtain 1.11 mmol of 3,7-dibromodibenzothiophene as a white solid. The obtained 5.17 mmol of 3,7-dibromodibenzothiophene was dissolved in 100 mL of tetrahydrofuran and cooled to -78°C. To the cooled reaction solution, 15.5 mmol of n-butyllithium hexane solution (1.57 M) was added dropwise over 30 minutes, and the mixture was stirred at low temperature for 2 hours. After stirring, finely crushed dry ice was added, and the mixture was stirred for 1 hour. After stirring at room temperature for 1 hour, tetrahydrofuran was removed by distillation, and then concentrated hydrochloric acid was added. The precipitated solid was filtered, washed with water and methanol, and then dried at 100°C to obtain 4.22 mmol of 3,7-dicarboxydibenzothiophene (organic ligand 6) as a colorless solid.

[0039] [Production Example 7] Synthesis of Organic Ligand 7 The same procedure as in Production Example 3 was followed, except that 3,7-dibromodibenzothiophene was used instead of 2,8-dibromodibenzothiophene, to obtain organic ligand 7 as a colorless solid.

[0040] [Production Example 8] Synthesis of Organic Ligand 8 The procedure was the same as in Production Example 4, except that 3,7-dibromodibenzothiophene was used instead of 2,8-dibromodibenzothiophene, and organic ligand 8 was obtained as a colorless solid.

[0041] [Production Example 9] Synthesis of Organic Ligand 9 Dibenzothiophene (10.0 mmol) was dissolved in hexane (10 mL), and N,N,N',N'-tetramethylethylenediamine (30.0 mmol) was added, and the mixture was cooled to -78°C. 30.0 mmol of n-butyllithium hexane solution (1.57 M) was added dropwise to the cooled reaction solution over 30 minutes, and the mixture was stirred at low temperature for 2 hours. After stirring, finely crushed dry ice was added and the mixture was stirred for 1 hour. After stirring at room temperature for another 1 hour, the hexane was removed by distillation, and then concentrated hydrochloric acid was added. The precipitated solid was filtered, washed with water and methanol, and dried at 100°C to obtain 4.44 mmol of 4,6-dicarboxydibenzothiophene (organic ligand 9) as a colorless solid.

[0042] The 1H-NMR data of the obtained organic ligands are shown below. organic ligand 1 1 H-NMR (400 MHz, DMSO-d6) δ: 8.09 (2H, dd), 8.19 (2H, d), 8.95 (2H, d). organic ligand 2 1 H-NMR (400 MHz, DMSO-d6) δ: 7.84 (2H, d), 8.16 (2H, dd), 8.89 (2H, d). organic ligand 3 1H-NMR (400 MHz, DMSO-d6) δ: 7.95 (2H, dd), 8.03-8.09 (8H, m), 8.17(2H, d), 9.02 (2H, d). Organic ligand 4 1 H-NMR (400 MHz, DMSO-d6) δ: 7.70-7.75 (6H, m), 8.00 (4H, d), 8.16(2H, d), 8.78 (2H, s). Organic ligand 5 1 H-NMR (400 MHz, DMSO-d6) δ: 7.75 (4H, d), 7.78(2H, d), 7.83 (2H, d), 7.99(4H, d), 8.52 (2H, s). Organic ligand 6 1 H-NMR (400 MHz, DMSO-d6) δ: 8.07 (2H, d), 8.55 (2H, dd), 8.68 (2H, s). Organic ligand 7 1 H-NMR (400 MHz, DMSO-d6) δ: 7.91 (2H, d), 7.95 (4H, d), 8.06(4H, d), 8.47(2H, s), 8.51 (2H, d). Organic ligand 8 1 H-NMR (400 MHz, DMSO-d6) δ: 7.69 (4H, d), 7.72(2H, d), 7.98(4H, d), 8.36(2H, s), 8.47(2H, d). Organic ligand 9 1 H-NMR (400 MHz, DMSO-d6) δ: 7.67 (2H, t), 8.20 (2H, dd), 8.70 (2H, dd).

[0043] [Example 1-1] Organic ligand 1 (0.5 mmol) and zinc nitrate hexahydrate (1.0 mmol) were mixed with 10 mL of DMF and heated in an oven (reaction conditions: 90°C, 48 hours). After returning to room temperature, the supernatant was removed. After washing with 10 mL of DMF, the solvent was removed and replaced with chloroform. 10 mL of chloroform was added and the mixture was immersed overnight. After removing the chloroform, the mixture was vacuum-dried at 150°C for 5 hours to obtain metal-organic structure 1-1 as a colorless solid.

[0044] [Examples 1-2] to [Examples 1-51] Except for the organic ligands, solvent, temperature, heating time, and organic ligand concentrations shown in Table 3 below, the same procedure as in Example 1-1 was followed to obtain metal-organic structures 1-2 to 1-51. The results are shown in Table 3. In Table 3, "Concentration (M)" was calculated as the proportion of organic ligands in the solvent. The solvent "DMF + MeOH" used in Example 1-34 is a mixed solvent of 9 mL of DMF and 1 mL of MeOH. In the table below, "Concentration (M)" refers to the concentration of the organic ligand, calculated as the proportion of the organic ligand in the solvent.

[0045] [Table 3] TIFF0007839512000012.tif123162

[0046] [Example 2-1] Organic ligand 1 (0.5 mmol) was dissolved in 7.5 mL of DMF, and auxiliary ligand 1 (0.2 mmol) and zinc nitrate hexahydrate (0.5 mmol) were added. The mixture was heated in an oven (reaction conditions: 90°C, 48 hours). After returning to room temperature, the supernatant was removed. After washing with 10 mL of DMF, the solvent was removed and replaced with chloroform. 10 mL of chloroform was added and the mixture was immersed overnight. After removing the chloroform, the mixture was vacuum-dried at 150°C for 5 hours to obtain metal-organic structure 2-1 as a colorless solid.

[0047] [Examples 2-2] to [Examples 2-33] Except for the organic ligands, auxiliary ligands, solvents, temperatures, heating times, and concentrations of organic ligands shown in Table 4 below, the same procedure as in Example 2-1 was followed to obtain metal-organic structures 2-2 to 2-33. The results are shown in Table 4. In Examples 2-5 and 2-7, a mixed solvent of 5 mL of DMF and 5 mL of NMP was used, and in Examples 2-6 and 2-8, a mixed solvent of 30 mL of DMF and 30 mL of NMP was used. In Examples 2-23 and 2-24, a mixed solvent of 5 mL of DMF, 1 mL of water, and 2 mL of EtOH was used.

[0048] [Table 4]

[0049] [Example 3-1] Organic ligand 1 (0.294 mmol) and aluminum nitrate nonahydrate (0.382 mmol) were mixed with 9.2 mL of DEF and heated in an oven (reaction conditions: 120°C, 168 hours). After returning to room temperature, the supernatant was removed. After washing with 10 mL of DEF, the solvent was removed and replaced with chloroform. 10 mL of chloroform was added and the mixture was immersed overnight. After removing the chloroform, the mixture was vacuum-dried at 150°C for 5 hours to obtain metal-organic structure 3-1 as a brown solid.

[0050] [Example 3-2]~[Example 3-8] Except for carrying out the reaction using the organic ligands, solvents, temperature, heating time, and organic ligand concentrations shown in Table 5 below, the same procedure as in Example 3-1 was followed to obtain metal-organic structures 3-2 to 3-8. The results are shown in Table 5.

[0051] [Table 5]

[0052] [Example 4-1] Organic ligand 6 (0.2 mmol) and copper nitrate trihydrate (0.2 mmol) were mixed with 9.2 mL of DEF and heated in an oven (reaction conditions: 120°C, 168 hours). After returning to room temperature, the supernatant was removed. After washing with 10 mL of DEF, the solvent was removed and replaced with chloroform. 10 mL of chloroform was added and the mixture was immersed overnight. After removing the chloroform, the mixture was vacuum-dried at 150°C for 5 hours to obtain metal-organic structure 4-1 as a pale blue-green solid.

[0053] [Example 4-2]~[Example 4-8] Except for carrying out the reaction using the organic ligands, solvents, temperature, and heating time shown in Table 6 below, the same procedure as in Example 4-1 was followed to obtain metal-organic structures 4-2 to 4-8. The results are shown in Table 6.

[0054] [Table 6]

[0055] [Example 5-1] Organic ligand 1 (0.2 mmol) was dissolved in 9.2 mL of DEF, and auxiliary ligand 2 (0.2 mmol) and copper nitrate trihydrate (0.2 mmol) were added. The mixture was heated in an oven (reaction conditions: 120°C, 48 hours). After returning to room temperature, the supernatant was removed. After washing with 10 mL of DMF, the solvent was removed and replaced with chloroform. 10 mL of chloroform was added and the mixture was immersed overnight. After removing the chloroform, the mixture was vacuum-dried at 150°C for 5 hours to obtain metal-organic structure 5-1 as a pale blue-green solid.

[0056] [Example 5-2]~[Example 5-27] Except for the organic ligands, auxiliary ligands, solvents, and temperatures shown in Table 7 below, the same procedure as in Example 5-1 was followed to obtain metal-organic structures 5-2 to 5-27. The results are shown in Table 7.

[0057] [Table 7]

[0058] [Example 6-1] Organic ligand 1 (0.2 mmol) and zirconium chloride (0.2 mmol) were mixed with 9.2 mL of DMF and heated in an oven (reaction conditions: 120°C, 168 hours). After returning to room temperature, the supernatant was removed. After washing with 10 mL of DMF, the solvent was removed and replaced with chloroform. 10 mL of chloroform was added and the mixture was immersed overnight. After removing the chloroform, the mixture was vacuum-dried at 150°C for 5 hours to obtain metal-organic structure 6-1 as a brown solid.

[0059] [Example 6-2]~[Example 6-8] Except for carrying out the reaction using the organic ligands, solvents, and temperatures shown in Table 8 below, the same procedure as in Example 6-1 was followed to obtain metal-organic structures 6-2 to 6-8. The results are shown in Table 8.

[0060] [Table 8]

[0061] [Example 7-1] Organic ligand 6 (0.2 mmol) was dissolved in 18 mL of DMF, and trifluoroacetic acid (1.7 mL) and zirconium chloride (0.2 mmol) were added as additives. The mixture was heated in an oven (reaction conditions: 120°C, 48 hours). After returning to room temperature, the supernatant was removed. After washing with 10 mL of DMF, the solvent was removed and replaced with chloroform. 10 mL of chloroform was added and the mixture was immersed overnight. After removing the chloroform, the mixture was vacuum-dried at 150°C for 5 hours to obtain metal-organic structure 7-1 as a pale blue-green solid.

[0062] [Examples 7-2] to [Examples 7-11] Except for carrying out the reaction with the additives, heating temperature, and concentration of organic ligands shown in Table 9 below, the same procedure as in Example 7-1 was followed to obtain metal-organic structures 7-2 to 7-11. The results are shown in Table 9.

[0063] [Table 9]

[0064] [Example 8-1] Organic ligand 1 (0.2 mmol) and nickel nitrate hexahydrate (0.2 mmol) were mixed with 9.2 mL of DMF and heated in an oven (reaction conditions: 120°C, 48 hours). After returning to room temperature, the supernatant was removed. After washing with 10 mL of DMF, the solvent was removed and replaced with chloroform. 10 mL of chloroform was added and the mixture was immersed overnight. After removing the chloroform, the mixture was vacuum-dried at 150°C for 5 hours to obtain metal-organic structure 8-1 as a brown solid.

[0065] [Example 8-2]~[Example 8-6] Except for carrying out the reaction using the organic ligands, solvents, heating temperatures, and concentrations of organic ligands shown in Table 10 below, the same procedure as in Example 8-1 was followed to obtain metal-organic structures 8-2 to 8-6. The results are shown in Table 10.

[0066] [Table 10]

[0067] [Example 9-1] Organic ligand 1 (0.2 mmol) and cobalt nitrate hexahydrate (0.2 mmol) were mixed with 9.2 mL of DMF and heated in an oven (reaction conditions: 120°C, 168 hours). After returning to room temperature, the supernatant was removed. After washing with 10 mL of DMF, the solvent was removed and replaced with chloroform. 10 mL of chloroform was added and the mixture was immersed overnight. After removing the chloroform, the mixture was vacuum-dried at 150°C for 5 hours to obtain metal-organic structure 9-1 as a pale purple solid.

[0068] [Example 9-2]~[Example 9-6] Except for using the organic ligands, solvents, heating times, and concentrations of organic ligands shown in Table 11 below, the same procedure as in Example 9-1 was followed to obtain metal-organic structures 9-2 to 9-6. The results are shown in Table 11.

[0069] [Table 11]

[0070] [Example 10-1] Organic ligand 1 (0.2 mmol) and chromium chloride hexahydrate (0.2 mmol) were mixed with 9.2 mL of DMF and heated in an oven (reaction conditions: 120°C, 168 hours). After returning to room temperature, the supernatant was removed. After washing with 10 mL of DMF, the solvent was removed and replaced with chloroform. 10 mL of chloroform was added and the mixture was immersed overnight. After removing the chloroform, the mixture was vacuum-dried at 150°C for 5 hours to obtain metal-organic structure 10-1 as a dark green solid.

[0071] [Example 10-2]~[Example 10-10] Except for carrying out the reaction using the organic ligands, solvents, temperature, and heating time shown in Table 12 below, the same procedure as in Example 10-1 was followed to obtain metal-organic structures 10-2 to 10-10. The results are shown in Table 12.

[0072] [Table 12]

[0073] [Example 11-1] Organic ligand 1 (0.2 mmol) and iron chloride hexahydrate (0.2 mmol) were mixed with 9.2 mL of DMF and heated in an oven (reaction conditions: 120°C, 48 hours). After returning to room temperature, the supernatant was removed. After washing with 10 mL of DMF, the solvent was removed and replaced with chloroform. 10 mL of chloroform was added and the mixture was immersed overnight. After removing the chloroform, the mixture was vacuum-dried at 150°C for 5 hours to obtain metal-organic structure 11-1 as an orange solid.

[0074] [Example 11-2]~[Example 11-6] Except for using the organic ligands, solvents, and temperatures shown in Table 13 below, the same procedure as in Example 11-1 was followed to obtain metal-organic structures 11-2 to 11-6. The results are shown in Table 13.

[0075] [Table 13]

[0076] [Example 12-1] Organic ligand 1 (0.2 mmol) and scandium chloride hexahydrate (0.2 mmol) were mixed with 9.2 mL of DMF and heated in an oven (reaction conditions: 120°C, 48 hours). After returning to room temperature, the supernatant was removed. After washing with 10 mL of DMF, the solvent was removed and replaced with chloroform. 10 mL of chloroform was added and the mixture was immersed overnight. After removing the chloroform, the mixture was vacuum-dried at 150°C for 5 hours to obtain metal-organic structure 12-1 as a colorless solid.

[0077] [Example 12-2]~[Example 12-6] Except for the organic ligands, solvents, temperatures, and heating times shown in Table 14 below, the same procedure as in Example 12-1 was followed to obtain metal-organic structures 12-2 to 12-6. The results are shown in Table 14.

[0078] [Table 14]

[0079] [Example 13-1] Organic ligand 1 (0.2 mmol) and molybdenum acetate dimer (0.1 mmol) were mixed with 9.2 mL of DEF and heated in an oven (reaction conditions: 120°C, 168 hours). After returning to room temperature, the supernatant was removed. After washing with 10 mL of DEF, the solvent was removed and replaced with chloroform. 10 mL of chloroform was added and the mixture was immersed overnight. After removing the chloroform, the mixture was vacuum-dried at 150°C for 5 hours to obtain metal-organic structure 13-1 as a brown solid.

[0080] [Example 13-2]~[Example 13-3] Except for carrying out the reaction using the organic ligands, solvents, temperature, and heating time shown in Table 15 below, the same procedure as in Example 13-1 was followed to obtain metal-organic structures 13-2 to 13-3. The results are shown in Table 15.

[0081] [Table 15]

[0082] [Example 14-1] Organic ligand 1 (0.2 mmol) and manganese chloride tetrahydrate (0.2 mmol) were mixed with 9.2 mL of DMF and heated in an oven (reaction conditions: 120°C, 168 hours). After returning to room temperature, the supernatant was removed. After washing with 10 mL of DMF, the solvent was removed and replaced with chloroform. 10 mL of chloroform was added and the mixture was immersed overnight. After removing the chloroform, the mixture was vacuum-dried at 150°C for 5 hours to obtain metal-organic structure 14-1 as a colorless solid.

[0083] [Example 14-2]~[Example 14-7] Except for carrying out the reaction using the organic ligands, solvents, temperature, and heating time shown in Table 16 below, the same procedure as in Example 14-1 was followed to obtain metal-organic structures 14-2 to 14-7. The results are shown in Table 16.

[0084] [Table 16]

[0085] [Example 15-1] Organic ligand 6 (0.01 mmol) was mixed with 10 mL of MeOH, 2 mL of EtOH, and 2 mL of water. Auxiliary ligand 5 (0.02 mmol), potassium carbonate (0.02 mmol), and manganese chloride tetrahydrate (0.02 mmol) were added, and the mixture was heated in an oven (reaction conditions: 80°C, 168 hours). After returning to room temperature, the supernatant was removed. After washing with 10 mL of DMF, the solvent was removed and replaced with chloroform. 10 mL of chloroform was added, and the mixture was immersed overnight. After removing the chloroform, the mixture was vacuum-dried at 150°C for 5 hours to obtain metal-organic structure 15-1 as a colorless solid.

[0086] [Example 16-1] Organic ligand 6 (0.2 mmol) and magnesium nitrate hexahydrate (0.2 mmol) were mixed with 9.2 mL of DMF and heated in an oven (reaction conditions: 120°C, 168 hours). After returning to room temperature, the supernatant was removed. After washing with 10 mL of DMF, the solvent was removed and replaced with chloroform. 10 mL of chloroform was added and the mixture was immersed overnight. After removing the chloroform, the mixture was vacuum-dried at 150°C for 5 hours to obtain metal-organic structure 16-1 as a colorless solid.

[0087] [Example 16-2]~[Example 16-5] Except for carrying out the reaction using the organic ligands, solvents, temperature, and heating time shown in Table 17 below, the same procedure as in Example 16-1 was followed to obtain metal-organic structures 16-2 to 16-5. The results are shown in Table 17.

[0088] [Table 17]

[0089] [Example 17-1] Organic ligand 6 (0.1 mmol) and zirconium oxychloride (0.1 mmol) were mixed with 2 mL of DMF and heated in an oven (reaction conditions: 120°C, 48 hours). After returning to room temperature, the supernatant was removed. After washing with 5 mL of DMF, the solvent was removed and replaced with chloroform. 5 mL of chloroform was added and the mixture was immersed overnight. After removing the chloroform, the mixture was vacuum-dried at 150°C for 5 hours to obtain metal-organic structure 17-1 as a pale yellow solid.

[0090] [Example 18-1] Organic ligand 6 (0.1 mmol) and titanium chloride (0.1 mmol) were mixed with 2 mL of DMF and heated in an oven (reaction conditions: 120°C, 48 hours). After returning to room temperature, the supernatant was removed. After washing with 5 mL of DMF, the solvent was removed and replaced with chloroform. 5 mL of chloroform was added and the mixture was immersed overnight. After removing the chloroform, the mixture was vacuum-dried at 150°C for 5 hours to obtain metal-organic structure 18-1 as a pale yellow solid.

[0091] [Example 19-1] Organic ligand 6 (0.1 mmol), manufactured by Matsumoto Fine Chemical Co., Ltd., Orgatics TC-400 (Ti(Oi-C3H7)2(C6H 14 0.1 mmol of O3N)2) was mixed with 2 mL of DMF and heated in an oven (reaction conditions: 120°C, 48 hours). After returning to room temperature, the supernatant was removed. After washing with 5 mL of DMF, the solvent was removed and replaced with chloroform. 5 mL of chloroform was added and the mixture was immersed overnight. After removing the chloroform, the mixture was vacuum-dried at 150°C for 5 hours to obtain metal-organic structure 19-1 as a colorless solid.

[0092] [Example 20-1] Organic ligand 6 (0.1 mmol) was dissolved in 2 mL of DMF, and auxiliary ligand 10 (0.1 mmol) and zinc nitrate hexahydrate (0.1 mmol) as a metal reagent were added. The mixture was heated in an oven (reaction conditions: 120°C, 48 hours). After returning to room temperature, the supernatant was removed. After washing with 5 mL of DMF, the solvent was removed and replaced with chloroform. 5 mL of chloroform was added and the mixture was immersed overnight. After removing the chloroform, the mixture was vacuum-dried at 150°C for 5 hours to obtain metal-organic structure 20-1 as a colorless solid.

[0093] [Example 20-2]~[Example 20-13] Except for using the metal salt or metal compound reagents shown in Table 18 below, the same procedure as in Example 20-1 was followed to obtain metal-organic structures 20-2 to 20-13. The results are shown in Table 18.

[0094] [Table 18]

[0095] (BET specific surface area measurement and hydrogen storage capacity measurement) For some of the obtained metal-organic structures, the BET specific surface area and hydrogen storage capacity at 77K-atmospheric pressure were measured. The BET specific surface area and hydrogen storage capacity at 77K-atmospheric pressure were measured using the Tristar-II gas adsorption analyzer (Micromeritics). The BET specific surface area was calculated using the following method: Approximately 50 mg of a metal-organic structure was placed inside a glass cell. The inside of the glass cell was reduced to a vacuum at a temperature of 135°C and dried for 6 hours. The glass cell was mounted on a gas adsorption amount measuring device and immersed in a constant temperature bath containing liquid nitrogen. The pressure of the nitrogen contained in the glass cell was gradually increased. When the pressure of the nitrogen introduced into the glass cell reached 1.0 × 10⁻⁶ 5 Measurements were continued until the reading reached Pa. The amount of hydrogen stored at 77K atmospheric pressure was calculated using the following method. After measuring nitrogen, the gas type was changed to hydrogen and measurements were taken. The pressure of the hydrogen contained in the glass cell was gradually increased. The pressure of the hydrogen introduced into the glass cell was 1.0 × 10⁻⁶. 5 Measurements were continued until the reading reached Pa. The measured BET specific surface area results are shown in Table 19. The measured hydrogen storage capacity at 77K-atmospheric pressure is also shown in Table 19.

[0096] [Table 19] TIFF0007839512000029.tif158160 [Industrial applicability]

[0097] The metal-organic structure of the present invention can store gases such as hydrogen at a practical level. Therefore, it can be suitably used in energy fields that utilize hydrogen, such as fuel cells.

Claims

1. A metal-organic structure formed by bonding a carboxylate ion represented by formula (1) with a polyvalent metal ion (wherein the metal-organic structure formed by bonding the carboxylate ion represented by formula (1), X in formula (1) is a sulfur atom, and m1, m2, n1 and n2 are all 0, COO － (Excluding cases where both are coupled in the 2nd and 8th positions). 【Chemistry 1】 (In formula (1), X is either a sulfur atom or an oxygen atom. R １ These are a hydroxyl group, a C1-6 alkyl group, a C1-6 alkoxy group, or a halogeno group. n1 and n2 are integers between 0 and 3. １ When there are 2 or more, each R １ They may be the same or different from each other. L is a divalent group represented by the following formula (2). m1 and m2 are 0 or 1. When L is 2 or greater, each L may be the same or different from the others. 【Chemistry 2】 In formula (2), R ２ These are a hydroxyl group, a C1-6 alkyl group, a C1-6 alkoxy group, or a halogeno group. n3 is an integer between 0 and 4. ２ When there are 2 or more, each R ２ They may be the same or different from each other. A hydrogen gas storage agent comprising the metal-organic structure, wherein * and ** represent the bonding position, and ** represents the bonding position with the carboxylate ion. The polyvalent metal ion is at least one metal ion selected from Zn, Al, Zr, Ni, Co, Cr, Fe, Sc, Mo, Mn, Ti, and Mg.

2. The hydrogen gas storage agent according to claim 1, further comprising a metal-organic structure as an auxiliary ligand.

3. A method for storing hydrogen gas, comprising the step of contacting a hydrogen gas storage agent according to claim 1 or 2 with a gas.

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