Carbon dioxide fixation materials and fixation methods

Abstract

To provide a new technique for fixing carbon dioxide under mild condition and with high efficiency.SOLUTION: A carbon dioxide fixing material according to the present invention contains a metal ion donor and an amine as a cross-linking ligand precursor. The amine is configured to react with carbon dioxide in the gaseous state to form a cross-linking ligand having at least one carbamate anion site. The cross-linking ligand is configured to react with the metal ion donor to form a coordination polymer in which a plurality of the metal ion are linked by the cross-linking ligand.SELECTED DRAWING: Figure 9A

Description

[Technical Field]

[0001] The present disclosure relates to materials and methods for sequestrating carbon dioxide. The present disclosure also relates to porous coordination polymers (PCPs) and methods for producing the same. [Background technology]

[0002] In recent years, there has been a growing demand for reducing greenhouse gas emissions in the global environment. As one approach to achieving this, methods for fixing carbon dioxide from gases such as air have been widely studied.

[0003] As a method for recovering carbon dioxide from gas, a method using an aqueous amine solution has already been put into practical use, and research is also underway into a method using an amine supported on a solid (Non-Patent Document 1).

[0004] On the other hand, a group of materials called metal-organic frameworks (MOFs) has been attracting attention in the fields of gas storage and gas separation. Many of these metal-organic frameworks are porous and can adsorb carbon dioxide into their pores. Therefore, the use of such metal-organic frameworks for carbon dioxide fixation and storage is also being considered.

[0005] Furthermore, in recent years, compounds in which diamines are bound to metal-organic frameworks (diamine-appended metal-organic frameworks) have also been reported (Non-Patent Document 2). When carbon dioxide is introduced into these compounds, the carbon dioxide is chemically inserted between the metal atom and the amine. [Prior art documents] [Non-patent literature]

[0006] [Non-Patent Document 1] Christopher W. Jones et al. “Direct Capture of CO2 from Ambient Air” Chem. Rev. 2016, 116, 19, 11840-11876 [Non-patent document 2] Thomas M. McDonald et al. “Cooperative insertion of CO2 in diamine-appended metal-organic frameworks” Nature, 2015, vol. 519, 303-308 Summary of the Invention [Problem to be solved by the invention]

[0007] In response to this, the present inventors have conducted extensive research to realize carbon dioxide fixation based on a new concept. An object of the present invention is to provide a new method for fixing carbon dioxide under mild conditions with high efficiency. [Means for solving the problem]

[0008] For example, aspects of the present invention are as follows. [1] A carbon dioxide fixation material comprising a metal ion donor and an amine as a bridging ligand precursor, wherein the amine is configured to react with gaseous carbon dioxide to form a bridging ligand having at least one carbamate anion site, and the bridging ligand is configured to react with the metal ion donor to form a coordination polymer in which a plurality of the metal ions are linked by the bridging ligand. [2] The carbon dioxide fixation material according to [1], wherein the amine has two or more primary amine groups or secondary amine groups and is configured to react with gaseous carbon dioxide to form a bridging ligand having two or more carbamate anion sites. [3] The amine is represented by the following general formula (1A): [ka] In the formula, R 1 is a hydrogen atom, an alkyl group, or R 1 and A form a heterocycle together with the nitrogen atom between them and A, A is a single bond or a linking group containing at least one carbon atom, and Q is a group configured to form an anionic moiety capable of coordinating to the metal ion. [4]R 1 is a hydrogen atom, or R 1 and A, together with the nitrogen atom between A and Q, form a heterocycle having two or less substituents other than Q. [5] The amine is represented by the following general formula (2A): [ka] In the formula, R 1 is a hydrogen atom, an alkyl group, or R 1 A forms a heterocyclic ring together with the nitrogen atom between R and A, and A is a single bond or a linking group containing at least one carbon atom, and R 2 is a hydrogen atom, an alkyl group, or R 2 and A together with the nitrogen atom between A and R 2 and the nitrogen atom between A and R 1 and the nitrogen atom between A and R 1 The carbon dioxide fixation material according to any one of [1] to [4], wherein the carbon dioxide fixation material is a heterocyclic ring formed together with [6]R 2 is a hydrogen atom, or R 2 The nitrogen atom between A and NHR together with A 1 or forms a heterocyclic ring having two or less substituents other than the group containing R 2 and the nitrogen atom between A and R 1 and the nitrogen atom between A and R 1 The carbon dioxide fixation material according to [5], wherein, together with [7] The carbon dioxide fixation material according to any one of [1] to [6], wherein the metal ion donor is configured to donate at least one metal ion selected from the group consisting of zinc ions, copper ions, zirconium ions, magnesium ions, iron ions, cobalt ions, chromium ions, and aluminum ions. [8] The carbon dioxide fixing material according to any one of [1] to [7], wherein the carbon dioxide content in the coordination polymer is 20% by mass or more. [9] The coordination polymer has a BET specific surface area of 10 m as calculated from the nitrogen adsorption isotherm at 77 K. 2 / g or more, or the carbon dioxide adsorption capacity at 195K and 1 atm is 15 cm 3 The carbon dioxide fixation material according to any one of [1] to [8], which is a porous coordination polymer having a specific surface area of (STP) / g or more.

[10] The carbon dioxide fixation material according to any one of [1] to [9], wherein the formation of the coordination polymer is performed under atmospheric pressure and room temperature conditions, or milder conditions.

[11] A method for fixing carbon dioxide, comprising: preparing a formulation containing a metal ion donor and an amine configured to react with gaseous carbon dioxide to form a bridging ligand having at least one carbamate anion site; and supplying a gas containing carbon dioxide to the formulation, thereby producing a coordination polymer in which a plurality of the metal ions are linked by the bridging ligand.

[12] A method for fixing carbon dioxide, comprising: a step of supplying a gas containing carbon dioxide to an amine to form a bridging ligand having at least one carbamate anion site; and a step of reacting the bridging ligand with a metal ion donor to produce a coordination polymer in which a plurality of the metal ions are linked by the bridging ligand.

[13] The method for fixing carbon dioxide according to

[11] or

[12] , wherein the coordination polymer is produced under atmospheric pressure and room temperature conditions or milder conditions.

[14] The method for fixating carbon dioxide according to any one of

[11] to

[13] , wherein the carbon dioxide-containing gas is air.

[15] A porous composite material comprising a plurality of metal ions and a plurality of bridging ligands, each having at least one carbamate anion site, wherein at least a portion of the metal ions are coordinated by the carbamate anion site, thereby connecting the metal ions and the bridging ligands to each other to form a porous framework, and wherein the BET specific surface area calculated from a nitrogen adsorption isotherm at 77 K is greater than or equal to 10 m. 2 / g or more, or the carbon dioxide adsorption capacity at 195K and 1 atm is 15 cm 3 (STP) / g or more.

[16] The porous coordination polymer according to

[15] , wherein the bridging ligand has two or more carbamate anion sites.

[17] The bridging ligand is represented by the following general formula (1B): [ka] In the formula, R 1 is a hydrogen atom, an alkyl group, or R 1 A forms a heterocyclic ring together with the nitrogen atom between Q and A, and A is a single bond or a linking group containing at least one carbon atom, - is an anion moiety capable of coordinating to the metal ion.

[18] The bridging ligand is represented by the following general formula (2B): [ka] In the formula, R 1 is a hydrogen atom, an alkyl group, or R 1 A forms a heterocyclic ring together with the nitrogen atom between R and A, and A is a single bond or a linking group containing at least one carbon atom, and R 2 is a hydrogen atom, an alkyl group, or R 2 and A together with the nitrogen atom between A and R 2 and the nitrogen atom between A and R 1 and the nitrogen atom between A and R 1The porous coordination polymer according to any one of

[15] to

[17] , wherein the heterocycle is formed together with

[19] A method for producing a porous coordination polymer, comprising: providing a formulation comprising a metal ion donor and an amine configured to react with gaseous carbon dioxide to form a bridging ligand having at least one carbamate anion moiety; and supplying a gas comprising carbon dioxide to the formulation.

[20] A method for producing a porous coordination polymer, comprising: supplying a gas containing carbon dioxide to an amine to form a bridging ligand having at least one carbamate anion site; and reacting the bridging ligand with a metal ion donor. [Effects of the Invention]

[0009] According to the present invention, it is possible to fix carbon dioxide under mild conditions with high efficiency. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 shows the PXRD patterns of compounds 1 to 4 and MOF-5. [Figure 2] FIG. 2 shows the PXRD patterns of compounds 1, 1A, 1B and 1C. [Figure 3] FIG. 3 shows the 1D 13C CP-MAS SSNMR spectrum of compound 1. [Figure 4] FIG. 4 shows the 2D 1H-13C HETCOR SSNMR spectrum of compound 1. [Figure 5] FIG. 5 shows the Zn K-edge XANES spectra of compound 1 and Zn-SBU. [Figure 6] FIG. 6 shows the Zn K-edge EXAFS spectrum of compound 1. [Figure 7] FIG. 7 shows the FT-IR spectra of compounds 1 to 4. [Figure 8] FIG. 8 shows the results of the Rietveld analysis of compound 1. [Figure 9A] FIG. 9A shows the packing structure of compound 1. [Figure 9B] FIG. 9B shows the packing structure of compound 2. [Figure 9C] FIG. 9C shows the packing structure of compound 3. [Figure 9D] FIG. 9D shows the packing structure of compound 4. [Figure 10] FIG. 10 shows the analysis of the first Bragg peaks of compounds 1-4. [Figure 11] FIG. 11 shows the change in the PXRD patterns of compounds 1 and 2 in air. [Figure 12A] FIG. 12A shows an SEM image of Compound 1. [Figure 12B] FIG. 12B shows an SEM image of Compound 2. [Figure 12C] FIG. 12C shows an SEM image of compound 3. [Figure 12D] FIG. 12D shows an SEM image of compound 4. [Figure 13] FIG. 13 shows the PXRD pattern of compound 2L. [Figure 14] FIG. 14 shows the PXRD pattern of compound 1D. [Figure 15] FIG. 15 shows the TGA profiles of compounds 1 to 4 under an Ar atmosphere. [Figure 16] FIG. 16 shows the nitrogen adsorption isotherms of compounds 1 to 4 at 77 K. [Figure 17] FIG. 17 shows the pore size distribution of compounds 1-4. [Figure 18] FIG. 18 shows the hydrogen adsorption isotherms at 77 K for compounds 1 to 4 and the isosteric adsorption heat curves versus the amount of hydrogen adsorbed. [Figure 19] FIG. 19 shows the carbon dioxide adsorption isotherms of compounds 1 to 4 at 195 K. [Figure 20] FIG. 20 shows the high-pressure carbon dioxide adsorption isotherm of compound 3 at 298 K. [Figure 21] FIG. 21 shows the nitrogen adsorption isotherms at 77 K for compounds 1, 1A, 1B, and 1C. [Figure 22] FIG. 22 shows the nitrogen adsorption isotherm of compound 2L at 77 K. [Figure 23] FIG. 23 shows the PXRD pattern of compound 5. [Figure 24] FIG. 24 shows the nitrogen adsorption isotherm at 77 K and the carbon dioxide adsorption isotherm at 195 K for compound 5. [Figure 25] FIG. 25 shows the TGA-DTA profile of compound 5. [Figure 26] FIG. 26 shows the solution NMR spectrum of compound 5. [Figure 27] FIG. 27 shows the PXRD patterns of compounds 6 and 6′ and UiO-66. [Figure 28] FIG. 28 shows the nitrogen adsorption isotherms at 77 K for compounds 6 and 6′. [Figure 29] FIG. 29 shows the FT-IR spectra of compounds 6 and 6′, compound 1, and Zr-SBU. [Figure 30] FIG. 30 shows the TGA profiles of compounds 6 and 6′. [Figure 31] FIG. 31 shows the Zr K-edge EXAFS spectra of compound 6′ and Zr-SBU. [Figure 32] FIG. 32 shows the PXRD patterns of compounds 7M, 7E, and 7iP, and Cu-JAST-1. [Figure 33] FIG. 33 shows the carbon dioxide adsorption isotherm at 195 K for compound 7E. [Figure 34] FIG. 34 shows the PXRD pattern of compound 8. [Figure 35] FIG. 35 shows the carbon dioxide adsorption isotherm of compound 8 at 195K. [Figure 36] FIG. 36 shows the TGA profile of compound 8. [Figure 37]FIG. 37 shows the PXRD patterns of compound 9 before and after gas adsorption. [Figure 38] FIG. 38 shows the nitrogen adsorption isotherm of compound 9 at 77K. [Figure 39] FIG. 39 shows the carbon dioxide adsorption isotherm of compound 9 at 195K. [Figure 40] FIG. 40 shows the FT-IR spectra of compound 9 and Zn-SBU. [Figure 41] FIG. 41 shows the TGA-DTA profile of compound 9. [Figure 42] FIG. 42 shows the PXRD pattern of compound 10. [Figure 43] FIG. 43 shows the PXRD patterns of compound 10, a coordination polymer of similar structure, and compound 10P. [Figure 44] FIG. 44 shows the FT-IR spectra of Compound 10 and Compound 10P. [Figure 45] FIG. 45 shows the nitrogen adsorption isotherm at 77 K and the carbon dioxide adsorption isotherm at 195 K for compound 10. [Figure 46] FIG. 46 shows the PXRD pattern of compound 11. [Figure 47] FIG. 47 shows the nitrogen adsorption isotherm of compound 11 at 77K. [Figure 48] FIG. 48 shows the carbon dioxide adsorption isotherm of compound 11 at 195K. [Figure 49] FIG. 49 shows the TGA-DTA profile of compound 11. [Figure 50] FIG. 50 shows the PXRD patterns of compound 12 and MOF-177. [Figure 51] FIG. 51 shows the FT-IR spectra of Compound 12 and Compound 1. [Figure 52] FIG. 52 shows the TGA-DTA profile of compound 12. [Figure 53] FIG. 53 shows the PXRD pattern of compound 13. [Figure 54] FIG. 54 shows the PXRD pattern of compound 14. [Figure 55] FIG. 55 shows the carbon dioxide adsorption isotherm of compound 14 at 195K. [Figure 56] FIG. 56 shows the FT-IR spectrum of compound 14. [Figure 57] FIG. 57 shows the TGA-DTA profile of compound 14. [Figure 58] FIG. 58 shows the PXRD pattern of compound 15. [Figure 59] FIG. 59 shows the carbon dioxide adsorption isotherm of compound 15 at 195K. [Figure 60] FIG. 60 shows the TGA-DTA profile of compound 15. [Figure 61] FIG. 61 shows the PXRD pattern of compound 16. [Figure 62] FIG. 62 shows the carbon dioxide adsorption isotherm of compound 16 at 195K. [Figure 63] FIG. 63 shows the TGA-DTA profile of compound 16. [Figure 64] FIG. 64 shows the TGA profiles of compound 2 and PZ-CO2 in air and under Ar atmosphere. [Figure 65] FIG. 65 shows the TGA and TPD profiles of Compound 2 and PZ-CO2 under an Ar atmosphere. [Figure 66] FIG. 66 shows the potential energy as a function of the Zn—O distance in the model structures of compound 1 and MOF-5. [Figure 67] FIG. 67 shows the model structure of compound 1 corresponding to the maximum and minimum potential energy values. DETAILED DESCRIPTION OF THE INVENTION

[0011] A carbon dioxide fixation material and fixation method according to one embodiment of the present invention will be described below. A porous coordination polymer and a method for producing the same according to one embodiment of the present invention will also be described. When referring to drawings or chemical formulas, components that exhibit the same or similar functions will be designated by the same reference symbols or symbols, and redundant explanations will be omitted.

[0012] First, a carbon dioxide fixing material according to one embodiment of the present invention will be described. This carbon dioxide fixing material contains a metal ion donor and an amine as a crosslinking ligand precursor.

[0013] The amine is configured to react with gaseous carbon dioxide to form a bridging ligand having at least one carbamate anion moiety, and the bridging ligand is then configured to react with a metal ion donor to form a coordination polymer in which multiple metal ions are linked by the bridging ligand.

[0014] That is, in this embodiment, the synthesized coordination polymer (or metal-organic framework) is not used as a carbon dioxide fixation material, but the process of synthesizing a coordination polymer having a specific structure is itself utilized for fixation of carbon dioxide, as will be described in detail below.

[0015] The type of metal ion donor constituting the carbon dioxide fixation material is not particularly limited as long as it can form a coordination polymer with the above-mentioned bridging ligand. For example, an appropriate metal ion donor can be selected based on the design principles of coordination polymers described below.

[0016] Examples of metal elements constituting the metal ion donor include any element belonging to alkali metals (Group 1), alkaline earth metals (Group 2), and transition metals (Groups 3 to 12). The metal element is, for example, selected from the group consisting of zinc, copper, zirconium, magnesium, calcium, iron, nickel, cobalt, chromium, manganese, and aluminum, and preferably selected from the group consisting of zinc, copper, zirconium, magnesium, iron, cobalt, chromium, and aluminum. That is, the metal ion donor is configured to donate a metal ion selected from the group consisting of zinc ions, copper ions, zirconium ions, magnesium ions, calcium ions, iron ions, nickel ions, cobalt ions, chromium ions, manganese ions, and aluminum ions, and preferably configured to donate a metal ion selected from the group consisting of zinc ions, copper ions, zirconium ions, magnesium ions, iron ions, cobalt ions, chromium ions, and aluminum ions. The metal ion donor may contain multiple metal elements. Alternatively, a plurality of metal ion donors containing different metal elements may be used in combination.

[0017] Typically, a metal salt is used as the metal ion donor. The metal ion donor may be an organic salt or an inorganic salt. The metal ion donor is typically selected from the group consisting of hydroxide salts, carbonate salts, acetate salts, sulfate salts, nitrate salts, and chloride salts. Multiple metal ion donors containing the same metal element may be used in combination.

[0018] The metal ion donor may be in the form of a so-called secondary building unit (SBU). Any secondary building unit used in the synthesis of known metal-organic frameworks can be selected as such a secondary building unit. Representative examples of secondary building units include the iron trimer cluster used in the synthesis of MIL, the zirconium hexamer cluster used in the synthesis of UiO-66, and the zinc tetramer cluster or cobalt tetramer cluster used in the synthesis of MOF-5.

[0019] As described above, the amine constituting the carbon dioxide fixation material is configured to react with gaseous carbon dioxide to form a bridging ligand having at least one carbamate anion moiety. This bridging ligand is then configured to react with the metal ion donor described above to form a coordination polymer in which multiple metal ions are linked by the bridging ligand. The formation of the carbamate anion moiety by the above reaction does not need to occur under any reaction conditions; it is sufficient that it occurs under specific reaction conditions when synthesizing the corresponding coordination polymer. The more thermodynamically stable the bridging ligand and / or coordination polymer, the more thermodynamically likely carbon dioxide fixation occurs.

[0020] The amine has at least one primary amine group (amino group) or secondary amine group and is configured to form a bridging ligand with at least one carbamate anion moiety.

[0021] The amine preferably has two or more primary or secondary amine groups and is configured to react with gaseous carbon dioxide to form a bridging ligand having two or more carbamate anion moieties, resulting in a coordination polymer in which, for example, multiple metal ions are linked via these two or more carbamate anion moieties.

[0022] When the amine has only one primary amine group or one secondary amine group, the amine must have at least one other coordinating site to function as a bridging ligand precursor. Examples of such coordinating sites other than the primary amine group or the secondary amine group include carboxyl groups, hydroxyl groups, sulfo groups, phosphate groups, and heterocyclic moieties. Of these, carboxyl groups are particularly preferred. That is, when the amine has only one primary amine group or one secondary amine group, the amine is preferably an amino acid.

[0023] The amine is, for example, a compound represented by the following general formula (1A). [ka]

[0024] This compound (1A) is configured to react with gaseous carbon dioxide under specific conditions to form a compound represented by the following general formula (1B), as shown in the following scheme. [ka]

[0025] In formulas (1A) and (1B), R 1 is a hydrogen atom, an alkyl group, or R 1 and A form a heterocycle together with the nitrogen atom between A and A, A is a single bond or a linking group containing at least one carbon atom; Q is a group configured to form an anionic moiety capable of coordinating to a metal ion; Q - is an anionic site capable of coordinating to a metal ion.

[0026] This compound (1B) can function as a bridging ligand that bridges multiple metal ions via at least the carbamate anion moiety shown and the anion moiety formed from Q. That is, this compound (1B) is configured to react with a metal ion donor under specific reaction conditions to form a coordination polymer in which multiple metal ions are linked by compound (1B). The more thermodynamically stable this bridging ligand and / or coordination polymer is, the more thermodynamically likely carbon dioxide fixation will occur.

[0027] In compounds (1A) and (1B), R 1When R is an alkyl group, the alkyl group preferably has 4 or less carbon atoms, and more preferably has 3 or less carbon atoms. Examples of such alkyl groups include methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, s-butyl, and t-butyl groups. 1 When is an alkyl group having a relatively small number of carbon atoms, the steric hindrance around the nitrogen atom of compound (1A) is relatively small, and therefore the nucleophilic reaction of the nitrogen atom of compound (1A) to carbon dioxide is not easily inhibited. In other words, in such a case, compound (1B) is relatively easily formed.

[0028] In compounds (1A) and (1B), R 1 But R 1 When a heterocycle is formed together with the nitrogen atom between R and A and A, the heterocycle may be, for example, a 5-membered or 6-membered ring, preferably a 6-membered ring. Preferred examples of such heterocycles include a piperidine structure and a pyrrolidine structure. The heterocycle may be formed by the addition of R 1 and A may further contain a heteroatom other than the nitrogen atom. This heterocycle may also have a substituent other than Q. In this case, however, it is preferable that the number of substituents other than Q is two or less. In this case, the steric hindrance around the nitrogen atom of compound (1A) is relatively small, so that the nucleophilic reaction of the nitrogen atom of compound (1A) with carbon dioxide is less likely to be inhibited. That is, in this case, compound (1B) is relatively easily formed. Furthermore, in this case, compound (1B) as a bridging ligand is less likely to be bulky, so that when the formed coordination polymer is porous, the adsorption of guest molecules to the coordination polymer is less likely to be inhibited.

[0029] When the heterocycle has a substituent other than Q, the substituent is preferably, but not limited to, an electron-donating group. In this case, the presence of the electron-donating group can improve the nucleophilicity of the nitrogen atom of compound (1A), thereby promoting the reaction of compound (1A) with carbon dioxide. That is, in such a case, compound (1B) is relatively easily formed. Examples of such electron-donating groups include alkyl groups, alkoxy groups, hydroxyl groups, primary amine groups (amino groups), secondary or tertiary amine groups, ester groups, and amide groups. When the substituent is an alkyl group, alkoxy group, secondary or tertiary amine group, ester group, or amide group, the number of carbon atoms in the substituent is preferably 3 or less. In such a case, steric hindrance around the nitrogen atom of compound (1A) is relatively reduced, so the nucleophilic reaction of the nitrogen atom of compound (1A) with carbon dioxide is less likely to be inhibited. That is, in such a case, compound (1B) is relatively easily formed. In addition, in such a case, the compound (1B) serving as a bridging ligand is less likely to become bulky, and therefore, when the formed coordination polymer is porous, the adsorption of guest molecules to the coordination polymer is less likely to be inhibited.

[0030] Furthermore, when the heterocycle has a substituent other than Q, the substituent is preferably a hydrophobic group. In this case, the presence of the hydrophobic group can improve the stability of the resulting coordination polymer against water or moisture. That is, in this case, the carbon dioxide fixation material can be easily used under high humidity conditions. Examples of such hydrophobic groups include alkyl groups.

[0031] Furthermore, when the heterocycle has a substituent other than Q, the substituent may be a substituent that promotes gas adsorption into the coordination polymer obtained by fixing carbon dioxide. Examples of such a substituent include a primary amine group (amino group), a secondary or tertiary amine group, and a perfluoro group.

[0032] In compounds (1A) and (1B), R 1 is preferably a hydrogen atom or an alkyl group having 3 or less carbon atoms, or R1 and A together with the nitrogen atom between A and R form a heterocyclic ring having two or less substituents other than Q, and more preferably, R is a hydrogen atom or 1 The nitrogen atom between Q and A, together with Q and A, forms a heterocycle having two or less substituents other than Q. In this case, as explained above, the steric hindrance around the nitrogen atom of compound (1A) is relatively small, so the nucleophilic reaction of compound (1A) with carbon dioxide is less likely to be inhibited. That is, in this case, compound (1B) is relatively easily formed. Furthermore, in this case, compound (1B) as a bridging ligand is less likely to be bulky, so that when the formed coordination polymer is porous, the adsorption of guest molecules is less likely to be inhibited.

[0033] In compounds (1A) and (1B), when A is a linking group containing at least one carbon atom, the linking group may be, for example, a divalent or trivalent linking group, preferably a divalent linking group. Examples of the linking group include an alkylene group, an alkenylene group, and an aromatic group. These linking groups may contain an ether bond, an ester bond, an amide bond, or the like in the molecular chain. These linking groups may also have a substituent as a side chain. The linking group may be appropriately selected from the viewpoints of the reactivity between the metal ion donor and the crosslinking ligand, the physical properties of the resulting coordination polymer, and the like.

[0034] When A as a linking group has a substituent as a side chain, examples of such a substituent include those previously described as the substituent that the heterocycle may have. Note that when A is a linking group containing at least one carbon atom, when this linking group has a substituent as a side chain, this substituent is not a substituent that can be substituted by R 1 It is preferable that the nucleophilic reaction of compound (1A) with carbon dioxide is inhibited by the steric hindrance around the nitrogen atom of compound (1A) because the steric hindrance around the nitrogen atom of compound (1A) is relatively small. In other words, compound (1B) is relatively easily formed in this case.

[0035] Furthermore, at least one of the above substituents may have the same properties as Q. That is, at least one of these substituents may be a group configured to form an anionic moiety capable of coordinating with a metal ion. This anionic moiety may be a carbamate anionic moiety, the same anionic moiety formed by Q, or a different anionic moiety from that formed by Q.

[0036] The linking group A is preferably not conjugated with the adjacent nitrogen atom, and is more preferably an alkylene group. When the linking group A is an alkylene group, the linking group is preferably a C1-C4 alkylene group. That is, A is preferably a methylene group, ethylene group, propylene group, or butylene group, which may have the above-mentioned substituents. In such cases, the formation of a bridging ligand and the reaction between the metal ion donor and the bridging ligand occur relatively easily, and the stability of the obtained coordination polymer is also relatively high. Examples of the linking group A being an alkylene group will be described in more detail later.

[0037] In compounds (1A) and (1B), A is R 1 and the nitrogen atom between A and R 1 It is particularly preferred that the heterocyclic ring is formed together with the alkylene group or the heterocyclic ring is an alkylene group. Examples of the preferred heterocyclic ring and alkylene group are as described above.

[0038] In compound (1A), Q is a group configured to form an anionic site capable of coordinating with a metal ion, and in chemical formula (1B), Q - is an anion moiety capable of coordinating with a metal ion. Examples of Q include a primary amine group (amino group), a secondary or tertiary amine group, a carboxyl group, a hydroxyl group, a sulfo group, a phosphate group, and a heterocyclic moiety. It is particularly preferred that Q is a primary amine group or a secondary amine group, or a carboxyl group. When Q is a primary amine group or a secondary amine, Q may be configured to react with gaseous carbon dioxide to form at least one carbamate anion moiety.

[0039] The amine is preferably a compound represented by the following general formula (2A): [ka]

[0040] This compound (2A) is configured to react with gaseous carbon dioxide under specific conditions to form a compound represented by the following general formula (2B), as shown in the following scheme. [ka]

[0041] In formulas (2A) and (2B), R 1 is a hydrogen atom, an alkyl group, or R 1 and A form a heterocycle together with the nitrogen atom between A and A, A is a single bond or a linking group containing at least one carbon atom; R 2 is a hydrogen atom, an alkyl group, or R 2 and A together with the nitrogen atom between A and R 2 and the nitrogen atom between A and R 1 and the nitrogen atom between A and R 1 Together with

[0042] Compounds (2A) and (2B) are compounds (1A) and (1B), respectively, in which Q is -NHR 2This corresponds to the case where compound (2B) can function as a bridging ligand bridging multiple metal ions via at least the two carbamate anion moieties shown. That is, compound (2B) is configured to react with a metal ion donor under specific reaction conditions to form a coordination polymer in which multiple metal ions are linked by compound (2B). The more thermodynamically stable this bridging ligand and / or coordination polymer is, the more thermodynamically likely carbon dioxide fixation will occur.

[0043] In formulas (2A) and (2B), R 1 and A are the same as those explained for formulas (1A) and (1B). When A is a linking group containing at least one carbon atom, and this linking group has a substituent as a side chain, this substituent may be R 2 It is preferable that the nucleophilic reaction of compound (2A) with carbon dioxide is inhibited by the steric hindrance around the nitrogen atom of compound (2A) because the steric hindrance around the nitrogen atom of compound (2A) is relatively small. In other words, compound (2B) is relatively easily formed in this case.

[0044] In formulas (2A) and (2B), R 2 is typically R 1 In this case, the symmetry of compound (2B) is improved, and the crystallinity of the resulting coordination polymer tends to be high.

[0045] In formulas (2A) and (2B), R 2 is an alkyl group, or R 2 When a heterocyclic ring is formed together with the nitrogen atom between A and A, examples of such alkyl groups and heterocyclic rings are as previously mentioned for R 1 The same as those explained above can be mentioned.

[0046] In formulas (2A) and (2B), R 2 But R 2 and the nitrogen atom between A and R 1 and the nitrogen atom between A and R 1When a heterocycle is formed together with (2A), the heterocycle may be, for example, a 5- or 6-membered ring, preferably a 6-membered ring. A particularly preferred example of such a heterocycle is a piperazine structure. The heterocycle may further contain a heteroatom other than the two nitrogen atoms. The heterocycle may also have a substituent. In this case, the number of substituents is preferably 2 or less. In this case, the steric hindrance around the nitrogen atom of compound (2A) is relatively small, so the nucleophilic reaction of the nitrogen atom of compound (2A) with carbon dioxide is less likely to be inhibited. That is, in this case, compound (2B) is relatively easily formed. Furthermore, in this case, compound (2B) as a bridging ligand is less likely to be bulky, so that when the formed coordination polymer is porous, the adsorption of guest molecules to the coordination polymer is less likely to be inhibited.

[0047] In compounds (2A) and (2B), R 2 is preferably a hydrogen atom, an alkyl group having 3 or less carbon atoms, or R 2 The nitrogen atom between A and NHR together with A 1 or forms a heterocyclic ring having two or less substituents other than the group containing R 2 and the nitrogen atom between A and R 1 and the nitrogen atom between A and R 1 Together with R, they form a heterocyclic ring having two or less substituents. 2 is more preferably a hydrogen atom, or 2 The nitrogen atom between A and NHR together with A 1 or forms a heterocyclic ring having two or less substituents other than the group containing R 2 and the nitrogen atom between A and R 1 and the nitrogen atom between A and R 1and form a heterocycle having two or less substituents. In this case, as explained above, the steric hindrance around the nitrogen atom of compound (2A) is relatively small, so the nucleophilic reaction of the nitrogen atom of compound (2A) with carbon dioxide is less likely to be inhibited. That is, in this case, compound (2B) is relatively easily formed. Furthermore, in this case, compound (2B) as a bridging ligand is less likely to become bulky, so that when the formed coordination polymer is porous, the adsorption of guest molecules to the coordination polymer is less likely to be inhibited.

[0048] As described above, preferred embodiments of the amine include those having a piperidine or piperazine structure, i.e., preferred examples of the amine include piperidine derivatives, or piperazine or its derivatives.

[0049] The amine is, for example, a compound represented by the following general formula (3A). [ka]

[0050] This compound (3A) is configured to react with gaseous carbon dioxide under specific conditions to form a compound represented by the following general formula (3B), as shown in the following scheme. [ka]

[0051] In formulas (3A) and (3B), X is a carbon atom or a nitrogen atom, A is a single bond or a linking group containing at least one carbon atom; Q is a group configured to form an anionic moiety capable of coordinating to a metal ion; Q - is an anionic moiety capable of coordinating to a metal ion, R 3 ~R 6are each independently a hydrogen atom or an arbitrary substituent, and R 3 and R 5 may be bonded to each other to form a ring, and R 4 and R 6 may be bonded to each other to form a ring.

[0052] In compounds (3A) and (3B), X is a carbon atom or a nitrogen atom. That is, compounds (3A) and (3B) have at least one nitrogen-containing six-membered ring. More specifically, compounds (3A) and (3B) have at least one piperidine or piperazine structure. By adopting such a structure, a relatively stable coordination polymer can be obtained. That is, by adopting such a structure, carbon dioxide fixation by the synthesis of a coordination polymer occurs thermodynamically more easily.

[0053] In compounds (3A) and (3B), examples of A and Q are the same as those described above for compounds (1A) and (1B). As described above, Q may be configured to react with gaseous carbon dioxide to form at least one carbamate anion moiety. In particular, Q may have a piperidine or piperazine structure similar to that shown in formulas (3A) and (3B).

[0054] In compounds (3A) and (3B), R 3 ~R 6are each independently a hydrogen atom or an arbitrary substituent. An electron-donating group is preferably used as such a substituent. In this case, the presence of the electron-donating group can improve the nucleophilicity of the nitrogen atom of compound (3A), thereby promoting the reaction of compound (3A) with carbon dioxide. That is, in such a case, compound (3B) is relatively easily formed. Examples of such electron-donating groups include alkyl groups, alkoxy groups, hydroxyl groups, primary amine groups (amino groups), secondary or tertiary amine groups, ester groups, and amide groups. When the substituent is an alkyl group, alkoxy group, secondary or tertiary amine group, ester group, or amide group, the number of carbon atoms in the substituent is preferably 3 or less. In such a case, steric hindrance around the nitrogen atom of compound (3A) is relatively small, so the nucleophilic reaction of the nitrogen atom of compound (3A) with carbon dioxide is less likely to be inhibited. That is, in such a case, compound (3B) is relatively easily formed. In addition, in such a case, the compound (3B) serving as a bridging ligand is less likely to become bulky, and therefore, when the formed coordination polymer is porous, the adsorption of guest molecules to the coordination polymer is less likely to be inhibited.

[0055] In compounds (3A) and (3B), R 3 ~R 6 Preferably, two or more of R are hydrogen atoms. 3 ~R 6 are all hydrogen atoms or R 3 ~R 6 It is preferred that only one or two of the R bonded to the carbon atom adjacent to the nitrogen atom be a substituent. 3 and R 4 Preferably, at least one of the groups is a hydrogen atom. In this case, the steric hindrance around the nitrogen atom of compound (3A) is relatively small, so that the nucleophilic reaction of the nitrogen atom of compound (3A) to carbon dioxide is less inhibited. That is, in this case, compound (3B) is relatively easily formed.

[0056] R 3 and R 5and are bonded to each other to form a ring, and / or R 4 and R 6 When R and R are bonded to each other to form a ring, the ring may be, for example, a 5- or 6-membered ring, and preferably a 6-membered ring. 3 ~R 6 The number of substituents among these is counted as two per ring.

[0057] The amine is, for example, a compound represented by the following general formula (4A). [ka]

[0058] This compound (4A) is configured to react with gaseous carbon dioxide under specific conditions to form a compound represented by the following general formula (4B), as shown in the following scheme. [ka]

[0059] In formulas (4A) and (4B), R 3 ~R 6 are each independently a hydrogen atom or an arbitrary substituent, and R 3 and R 5 may be bonded to each other to form a ring, and R 4 and R 6 may be bonded to each other to form a ring.

[0060] As is clear from the chemical formula, compounds (4A) and (4B) have at least one piperazine structure. That is, compound (4A) is piperazine or its derivative. By adopting such a structure, a particularly stable coordination polymer can be obtained. That is, by adopting such a structure, carbon dioxide fixation by synthesis of the coordination polymer occurs thermodynamically more easily.

[0061] In compounds (4A) and (4B), R 3 ~R 6 Examples of R bonded to the carbon atom adjacent to the nitrogen atom include those described above for compounds (3A) and (3B). 5 and R 6 At least one of the groups is preferably a hydrogen atom.

[0062] As explained above for the compounds (1A) and (2A), in the above amine, it is also preferable that A as a linking group is an alkylene group. In this case, not only are the chemical properties of the amine advantageous, but also the fact that the amine is available at a relatively low cost is advantageous.

[0063] The amine is, for example, a compound represented by the following general formula (5A). [ka]

[0064] This compound (5A) is configured to react with gaseous carbon dioxide under specific conditions to form a compound represented by the following general formula (5B), as shown in the following scheme. [ka]

[0065] In formulas (5A) and (5B), R 1 is a hydrogen atom or an alkyl group R 2 is a hydrogen atom or an alkyl group, n is 0 or a natural number.

[0066] In compounds (5A) and (5B), R 1 and R 2 Examples of R include those described above for compounds (2A) and (2B). 1 and R 2and are preferably both hydrogen atoms.

[0067] In the compounds (5A) and (5B), n is 0 or a natural number, preferably a natural number, and more preferably a natural number from 1 to 4. That is, the compound (5A) preferably has an alkylene group, and more preferably has a methylene group, an ethylene group, a propylene group, or a butylene group.

[0068] Specific examples of the above amine include the following compounds: These are merely examples, and do not exclude the use of compounds other than these.

[0069] [ka]

[0070] [ka]

[0071] [ka]

[0072] The carbon dioxide fixing material may contain multiple types of amines. In this case, it is sufficient that at least one of the multiple amines reacts with gaseous carbon dioxide to form a bridging ligand having at least one carbamate anion moiety. That is, the carbon dioxide fixing material may contain two or more types of amines as bridging ligand precursors, or may further contain an amine that does not function as a bridging ligand precursor.

[0073] Here, in the carbon dioxide fixation material according to one embodiment of the present invention, as described above, a synthesis process of a coordination polymer using carbamate anions is utilized. The combination of the metal ion donor and the amine as the bridging ligand precursor described above is arbitrary as long as the following conditions are satisfied:

[0074] (Condition 1) The amine is configured to react with gaseous carbon dioxide to form a bridging ligand having at least one carbamate anion site (hereinafter also referred to as a carbamate ligand). (Condition 2) The carbamate ligand is configured to react with a metal ion donor to form a coordination polymer in which a plurality of metal ions are linked by bridging ligands.

[0075] Various combinations of metal ion donors and amines that satisfy these conditions are conceivable, and all of these are within the scope of the present invention. When selecting a specific combination, for example, the following design principles can be adopted.

[0076] In this exemplary design principle, an existing metal-organic framework is first selected as a motif. Next, an amine with a similar structure to the ligand used in the synthesis of the metal-organic framework is designed. A coordination polymer with a similar structure is then synthesized by performing a similar synthesis in the presence of the amine and carbon dioxide. Specific examples include the combinations shown in Table 1 below.

[0077] [Table 1]

[0078] It should be noted that the above-mentioned Table 1 is merely an example, and other existing metal organic frameworks may be used as motifs. Furthermore, in the amine or carbamate ligands having similar structures in the above-mentioned design principles, modification with a substituent may be appropriately performed from the viewpoint of controlling reactivity, etc. Furthermore, the above-mentioned design principles are merely an example, and combinations of metal ion donors and amines that do not use existing metal organic frameworks as motifs are of course also possible.

[0079] As described above, the carbon dioxide fixation material according to this embodiment utilizes the synthesis of a coordination polymer by the reaction of a metal ion donor with a carbamate ligand. The advantages of using a carbamate ligand in the fixation of carbon dioxide using the synthesis of such a coordination polymer will be described below.

[0080] First, it is extremely difficult to use carbon dioxide itself as a bridging ligand in a coordination polymer due to its reactivity and molecular size. Therefore, when fixing carbon dioxide using the synthesis of coordination polymers, a strategy of incorporating carbon dioxide into the bridging ligand is considered.

[0081] As suggested by Table 1 above, dicarboxylate or tricarboxylate ligands have been widely used as bridging ligands in coordination polymers. However, synthesizing such carboxylate ligands from carbon dioxide requires high-energy reactants, catalysts, and / or harsh reaction conditions in multi-step reactions. Therefore, utilizing the formation of carboxylate ligands from carbon dioxide in the fixation of carbon dioxide through the synthesis of coordination polymers is not practical from the standpoint of energy efficiency, etc.

[0082] Carbon dioxide also converts to carbonate ions (CO3 2- ) and formate ions (HCO2 - However, there are many limitations in terms of the stability and diversity of the resulting coordination polymers. Furthermore, due to the small molecular size of carbonate and formate ions, it is difficult to obtain porous coordination polymers, as described below.

[0083] In contrast, the use of carbamate ligands in carbon dioxide fixation using coordination polymer synthesis has several advantages.

[0084] Typically, carbamate anions are thermodynamically unstable and readily undergo a reaction that converts them back to amines upon carbon dioxide separation. However, the present inventors have discovered that by coordinating carbamate anions to metal ions, the carbamate structure can be stably incorporated into a coordination polymer (see Examples for details). This mechanism allows the carbon dioxide fixation material of this embodiment to thermodynamically promote the formation of a bridging ligand through the reaction between an amine and carbon dioxide, and the formation of a coordination polymer through the reaction between a metal ion donor and the bridging ligand. Therefore, by utilizing these reactions, carbon dioxide fixation can be achieved efficiently under milder conditions.

[0085] Furthermore, carbamate ligands and their precursor amines can have a wide variety of structures. Therefore, the combination of metal ion donors and amines can be appropriately adjusted to design an optimal combination depending on the required application. Similarly, by changing the combination, it is possible to control the physical properties of the resulting coordination polymer.

[0086] The carbon dioxide fixing material according to this embodiment may further contain other components in addition to the metal ion donor and the amine.

[0087] For example, the carbon dioxide fixation material may further contain a ligand other than an amine or a carbamate ligand obtained therefrom, or a precursor thereof. Such an auxiliary ligand may be a bridging ligand or a monodentate ligand.

[0088] The carbon dioxide fixing material may further contain a solvent as needed. For example, a first solvent for dissolving the metal ion donor and a second solvent for dissolving the amine may be used in combination. The first solvent and the second solvent may be the same or different. It is preferable to use a liquid that easily dissolves gaseous carbon dioxide as the solvent.

[0089] There are no particular limitations on the solvent that can be used. For example, alcohol, an aprotic solvent, or water can be used as the solvent. It is preferable to use an alcohol or an aprotic solvent as the solvent. Examples of alcohol include methanol, ethanol, and isopropanol. Examples of aprotic solvents include amides such as N,N-dimethylformamide (DMF), nitriles such as acetonitrile, and ethers such as tetrahydrofuran (THF). These solvents may be dehydrated before use. A mixture of multiple solvents may also be used.

[0090] The carbon dioxide fixation material may further contain an additional substance such as a reaction accelerator. The reaction accelerator is, for example, a basic substance. It is preferable to use such a basic substance that is unlikely to undergo a nucleophilic reaction with carbon dioxide. That is, it is preferable to use a non-nucleophilic base as the basic substance. Examples of such non-nucleophilic bases include diazabicycloundecene (DBU), 1,1,3,3-tetramethylguanidine (TMG), N,N-diisopropylethylamine (DIPEA), 2,6-lutidine, pyridine, and imidazole. A reaction inhibitor may be added as an additional substance. From the viewpoint of controlling complexation, for example, ammonium acetate or sodium acetate may be used as the reaction inhibitor. Furthermore, a catalyst may be added as necessary.

[0091] As explained above, the use of the carbon dioxide fixation material according to this embodiment makes it possible to fix carbon dioxide under mild conditions and with high efficiency. For example, the formation of a coordination polymer accompanying carbon dioxide fixation in this embodiment can be carried out under atmospheric pressure and room temperature conditions, or milder conditions. That is, the formation of a coordination polymer accompanying carbon dioxide fixation in this embodiment can be carried out under ambient conditions or conditions milder than ambient conditions. In such cases, carbon dioxide fixation can be carried out under more environmentally friendly conditions. Here, "ambient conditions" refers to conditions in which no additional heating or pressure is applied, and specifically refers to conditions of room temperature (ambient temperature) and normal pressure (atmospheric pressure) in the environment in which the carbon dioxide fixation material is used. "Atmospheric pressure and conditions milder than room temperature" and "conditions milder than ambient conditions" refer to conditions of temperature and pressure lower than room temperature and normal pressure.

[0092] As described above, when the carbon dioxide fixation material according to this embodiment is used, a coordination polymer is produced. That is, the carbon dioxide fixation material after use produces a coordination polymer. This coordination polymer may have, for example, the following properties.

[0093] The carbon dioxide fixation material preferably has a carbon dioxide content of 20% by mass or more in its structure, more preferably 25% by mass or more, and particularly preferably 30% by mass or more. The higher the carbon dioxide content in the coordination polymer, the more efficiently the carbon dioxide fixation by the carbon dioxide fixation material can be achieved. Note that the "carbon dioxide content" here is a theoretical value calculated from the composition formula of the coordination polymer.

[0094] The coordination polymer may be crystalline or amorphous. The coordination polymer is preferably crystalline. When the coordination polymer is crystalline, it is suggested that the carbamate ligands are regularly incorporated into the coordination polymer framework. Since such a structure is thermodynamically advantageous, the crystalline nature of the resulting coordination polymer means that carbon dioxide fixation using the carbon dioxide fixation material according to this embodiment is likely to occur. Here, a "crystalline" coordination polymer means that a sharp or broad peak is observed near 2θ=10° in powder X-ray diffraction (PXRD) measurement using a CuKα anode, and an "amorphous" coordination polymer means that such a peak is not observed.

[0095] When the coordination polymer is crystalline, it is preferable that the coordination polymer has high crystallinity. Here, "high crystallinity" means that the half-width of the maximum intensity peak at around 2θ=10° is 3° or less in powder X-ray diffraction (PXRD) measurement using a CuKα anode.

[0096] The coordination polymer may be porous as described above. Here, the term "porous" refers to a coordination polymer having a BET specific surface area of 10 m or more calculated from a nitrogen adsorption isotherm at 77 K. 2 / g or more, or the carbon dioxide adsorption capacity at 195K and 1 atm is 15 cm 3 (STP) / g or more. When the coordination polymer is porous, the obtained coordination polymer itself can be further utilized for gas storage, etc. In particular, the obtained coordination polymer itself can be further utilized as a carbon dioxide fixation material. The properties of such porous coordination polymers will be described in more detail later.

[0097] When the obtained coordination polymer itself can be used as a further carbon dioxide fixation material, the maximum carbon dioxide adsorption capacity of the coordination polymer is preferably 20% by mass or more, more preferably 25% by mass or more, and particularly preferably 30% by mass or more. In this case, the sum of the carbon dioxide content and the maximum adsorption capacity is preferably 40% by mass or more, more preferably 50% by mass or more, and particularly preferably 60% by mass or more. In such cases, the product obtained by carbon dioxide fixation can be further utilized for carbon dioxide fixation, further improving the effective carbon dioxide fixation efficiency. The "maximum carbon dioxide adsorption capacity" here is a value obtained by conducting a carbon dioxide adsorption experiment at 298 K under high pressure, and corresponds to the carbon dioxide adsorption capacity when the pores of the porous coordination polymer are almost completely filled with carbon dioxide.

[0098] As described above, in the carbon dioxide fixation material according to this embodiment, the amine is configured to react with gaseous carbon dioxide to form a bridging ligand having at least one carbamate anion moiety. This bridging ligand is then configured to react with a metal ion donor to form a coordination polymer in which multiple metal ions are linked by the bridging ligand. However, the formation of the bridging ligand and the formation of the coordination polymer do not necessarily occur in separate steps. For example, the formation of the carbamate anion moiety and its coordination to the metal ion may occur simultaneously. Alternatively, a reaction mechanism may be utilized in which carbon dioxide activated by a metal ion reacts with the amine to form the carbamate anion moiety.

[0099] In the carbon dioxide fixation material according to this embodiment, a metal ion donor and an amine may react to form a precursor of the coordination polymer. In this case, for example, a metal complex may be formed in advance between a metal ion and an amine. This metal complex may then react with gaseous carbon dioxide to form the coordination polymer in which the metal ions are crosslinked by a bridging ligand having at least one carbamate anion moiety. The metal complex serving as the precursor of the coordination polymer may itself be another coordination polymer, but it is more preferable that it does not have a structure in which most of the metal ions are linked in advance, and that the structure becomes a mostly linked coordination polymer only after the carbamate anion moiety is formed by the introduction of carbon dioxide. That is, in the structure in which a metal complex is formed in advance between a metal ion and an amine, the metal complex serving as the precursor of the coordination polymer is more preferably not a coordination polymer.

[0100] Next, a method for fixing carbon dioxide according to one embodiment of the present invention will be described. In this method for fixing carbon dioxide, the above-mentioned carbon dioxide fixing material is typically used, but the metal ion donor and amine constituting the carbon dioxide fixing material do not necessarily need to be present at the same time. For example, in this method for fixing carbon dioxide, the metal ion donor and amine may be introduced sequentially.

[0101] A first example of the method for fixing carbon dioxide according to this embodiment includes the steps of: preparing a formulation containing a metal ion donor and an amine configured to react with gaseous carbon dioxide to form a bridging ligand having at least one carbamate anion moiety; and supplying a gas containing carbon dioxide to the formulation, thereby producing a coordination polymer in which multiple metal ions are linked by the bridging ligand.

[0102] That is, this first example involves supplying a gas containing carbon dioxide to the above-mentioned carbon dioxide fixation material. As described above, this achieves fixation of carbon dioxide using the coordination polymer synthesis process. As described above, in this case, the above-mentioned formulation may previously form a metal complex as a precursor of the coordination polymer.

[0103] A second example of the method for fixing carbon dioxide according to this embodiment includes the steps of: supplying a gas containing carbon dioxide to an amine to form a bridging ligand having at least one carbamate anion moiety; and reacting the bridging ligand with a metal ion donor to produce a coordination polymer in which multiple metal ions are linked by the bridging ligand.

[0104] In other words, this second example involves a step of forming a bridging ligand by reacting an amine with carbon dioxide, and a step of producing a coordination polymer by reacting the resulting bridging ligand with a metal ion donor. This method also allows for the fixation of carbon dioxide using the synthesis process of the coordination polymer described above.

[0105] As examples of the metal ion donor and amine used in each of the above examples, the same ones as those explained above for the carbon dioxide fixing material can be used.

[0106] The carbon dioxide-containing gas used in each of the above examples is, for example, air, preferably dry air. Alternatively, this gas may be a carbon dioxide-containing gas derived from a specific point source. Note that the gas may be a gas consisting essentially of carbon dioxide.

[0107] As described above, the above-described carbon dioxide fixation method enables carbon dioxide to be fixed under mild conditions with high efficiency. In particular, this carbon dioxide fixation method is preferably carried out under ambient conditions or conditions milder than ambient conditions.

[0108] The fixation of carbon dioxide by the above method is typically carried out in a solvent. In addition, additional substances such as a reaction accelerator may be further used in each step of the above method. Examples of these solvents and additional substances include those described above in relation to the carbon dioxide fixation material.

[0109] Next, a porous coordination polymer according to one embodiment of the present invention will be described. This porous coordination polymer is typically obtained by the fixation of carbon dioxide by the above-mentioned method. The porous coordination polymer thus obtained can have excellent properties by itself. However, this porous coordination polymer may also be synthesized by a method that does not involve the fixation of carbon dioxide.

[0110] A porous coordination polymer according to one embodiment of the present invention comprises a plurality of metal ions and a plurality of bridging ligands, each having at least one carbamate anion moiety. At least a portion of the metal ions are coordinated by the carbamate anion moiety, thereby connecting the metal ions and the bridging ligands to each other to form a porous framework. Furthermore, as will be described in detail later, this porous coordination polymer has a BET specific surface area of 10 m or more calculated from a nitrogen adsorption isotherm at 77 K. 2 / g or more, or the carbon dioxide adsorption capacity at 195K and 1 atm is 15 cm 3 (STP) / g or more.

[0111] Examples of the metal ions constituting the porous coordination polymer include the same metal ions as those previously explained as the metal ions that can be donated by the metal ion donor.

[0112] The bridging ligands having at least one carbamate anion moiety can be similar to those described above, and preferably have two or more carbamate anion moieties.

[0113] As mentioned above, carbamate structures are inherently thermodynamically unstable, but by coordinating carbamate anions to metal ions, the carbamate structures can be stably incorporated into coordination polymers. This stabilization is particularly pronounced when metal ions and bridging ligands are interconnected to form porous frameworks.

[0114] The bridging ligand is, for example, a compound represented by the following general formula (1B). [ka]

[0115] In formula (1B), R 1 is a hydrogen atom, an alkyl group, or R 1 and A form a heterocycle together with the nitrogen atom between A and A, A is a single bond or a linking group containing at least one carbon atom; Q - is an anionic site capable of coordinating to the metal ion.

[0116] R in compound (1B) 1 , A, and Q - Preferred examples of are the same as those described above. The more easily the fixation of carbon dioxide described above occurs thermodynamically, the more easily the porous coordination polymer containing compound (1B) as a bridging ligand becomes thermodynamically stable.

[0117] The bridging ligand may be a compound represented by the following general formula (2B): [ka]

[0118] In formula (2B), R 1 is a hydrogen atom, an alkyl group, or R 1 and A form a heterocycle together with the nitrogen atom between A and A, A is a single bond or a linking group containing at least one carbon atom; R 2 is a hydrogen atom, an alkyl group, or R 2 and A together with the nitrogen atom between A and R 2 and the nitrogen atom between A and R 1 and the nitrogen atom between A and R 1 Together with

[0119] R in compound (2B) 1 , A, and R 2 Preferred examples of are the same as those described above. The more easily the fixation of carbon dioxide described above occurs thermodynamically, the more easily the porous coordination polymer containing compound (2B) as a bridging ligand becomes thermodynamically stable.

[0120] The bridging ligand may be a compound represented by the following general formula (3B): [ka]

[0121] In formula (3B), X is a carbon atom or a nitrogen atom, A is a single bond or a linking group containing at least one carbon atom; Q - is an anionic moiety capable of coordinating to a metal ion, R 3 ~R 6 are each independently a hydrogen atom or an arbitrary substituent, and R 3 and R 5 may be bonded to each other to form a ring, and R 4 and R 6 may be bonded to each other to form a ring.

[0122] X, A, and Q in compound (3B) - , and R 3 ~R 6Preferred examples of are the same as those described above. The more thermodynamically likely the fixation of carbon dioxide described above occurs, the more likely the porous coordination polymer containing compound (3B) as a bridging ligand becomes thermodynamically stable.

[0123] The bridging ligand may be a compound represented by the following general formula (4B): [ka]

[0124] In formula (4B), R 3 ~R 6 are each independently a hydrogen atom or an arbitrary substituent, and R 3 and R 5 may be bonded to each other to form a ring, and R 4 and R 6 may be bonded to each other to form a ring.

[0125] R in compound (4B) 3 ~R 6 Preferred examples of are the same as those described above. The more easily the fixation of carbon dioxide described above occurs thermodynamically, the more easily the porous coordination polymer containing compound (4B) as a bridging ligand becomes thermodynamically stable.

[0126] The bridging ligand may be a compound represented by the following general formula (5B): [ka]

[0127] In formula (5B), R 1 is a hydrogen atom or an alkyl group R 2 is a hydrogen atom or an alkyl group, n is 0 or a natural number.

[0128] R in compound (5B)1 , R 2 Preferred examples of n and n are the same as those described above. The more easily the fixation of carbon dioxide described above occurs thermodynamically, the more easily the porous coordination polymer containing compound (5B) as a bridging ligand becomes thermodynamically stable.

[0129] As described above, in the porous coordination polymer according to this embodiment, metal ions and bridging ligands having at least one carbamate anion moiety are linked to each other to form a porous framework. By introducing the carbamate anion moiety into the porous framework, the thermodynamic stability of the carbamate anion moiety can be improved.

[0130] The porous coordination polymer according to this embodiment has a BET specific surface area of 10 m as calculated from a nitrogen adsorption isotherm at 77 K. 2 / g or more, and 15m 2 / g or more, and 2 / g or more is more preferable, and 100m 2 / g or more is more preferable, 2 / g or more is particularly preferable. It is suggested that the larger the BET specific surface area, the more excellent the porosity of the coordination polymer.

[0131] The porous coordination polymer according to this embodiment has a carbon dioxide adsorption capacity of 15 cm at 195 K and 1 atm. 3 (STP) / g or more, and 20cm 3 (STP) / g or more is more preferable, and 40cm 3 (STP) / g or more is more preferable, and 3 It is particularly preferable that the carbon dioxide adsorption amount is at least (STP) / g. The larger the carbon dioxide adsorption amount, the more excellent the porosity of the coordination polymer.

[0132] The porous coordination polymer according to this embodiment can be used, for example, for gas adsorption and storage. Furthermore, this porous coordination polymer may be applicable as a functional material such as a catalyst by utilizing the metal ions and / or carbamate structures in its skeleton. As mentioned above, this porous coordination polymer itself can also be used as a carbon dioxide fixation material.

[0133] A method for producing a porous coordination polymer according to one embodiment of the present invention will be described below. The method for producing a porous coordination polymer according to this embodiment utilizes the carbon dioxide fixation process described above.

[0134] A first example of a method for producing a porous coordination polymer according to this embodiment includes the steps of providing a formulation including a metal ion donor and an amine configured to react with gaseous carbon dioxide to form a bridging ligand having at least one carbamate anion moiety, and supplying a gas including carbon dioxide to the formulation.

[0135] A second example of the method for producing a porous coordination polymer according to this embodiment includes the steps of supplying a gas containing carbon dioxide to an amine to form a bridging ligand having at least one carbamate anion moiety, and reacting the bridging ligand with a metal ion donor.

[0136] In these manufacturing methods, the metal ion donor, amine, bridging ligand, and carbon dioxide-containing gas may be, for example, the same as those described above in relation to the carbon dioxide fixation method. These manufacturing methods are typically carried out in a solvent. Additional substances such as a reaction accelerator may also be used in each step of the manufacturing methods. These solvents and additional substances may be, for example, the same as those described above in relation to the carbon dioxide fixation material and fixation method. [Example]

[0137] The carbon dioxide fixing material and fixing method, as well as the porous coordination polymer and production method thereof will be further described below with reference to examples.

[0138] Carbon dioxide fixation through the synthesis of coordination polymers First, we will explain the specific method for carbon dioxide fixation accompanied by the synthesis of a coordination polymer. The reagents used were purchased from Sigma-Aldrich (Merck Co., Ltd.), Tokyo Chemical Industry Co., Ltd., Wako Pure Chemical Industries, Ltd., or Nacalai Tesque, Inc. The abbreviations used below are as shown in Table 2.

[0139] [Table 2-1]

[0140] [Table 2-2]

[0141] [Table 2-3]

[0142] Example 1 [Method 1] In a glove box filled with Ar, 100 mL of a DMF solution of Zn(OAc)2·2H2O (878.0 mg, 4.00 mmol) was mixed with 100 mL of an isopropanol solution of HPZ (258.4 mg, 3.00 mmol) and DBU (1.795 mL, 12.0 mmol) in a 300 mL round-bottom flask at 25 °C and atmospheric pressure. The resulting clear solution was stirred for 3 minutes. The flask was sealed with a rubber stopper and removed from the glove box. In this way, the carbon dioxide fixation material of Example 1 was obtained.

[0143] Next, CO2 gas (>99.99%) was introduced into the flask at 25°C and atmospheric pressure. As a result, a white precipitate was immediately obtained (<10 seconds). The reaction mixture was stirred overnight while introducing CO2 gas, and the reaction was completed. Visual observation showed that the reaction was almost complete within a few hours. In this way, carbon dioxide fixation using the carbon dioxide fixation material of Example 1 was carried out.

[0144] The flask was purged with Ar and returned to the inside of the glove box. The resulting precipitate was filtered. The solution was separated, washed with DMF and isopropanol under Ar, and dried in vacuum at 25°C. Thus, the coordination polymer [Zn4O(PDC)3] was obtained (yield 80%; C 18 H 24 NO 13 Calculated values for Zn4: C, 27.23; H, 3.05; N, 10.59. Found values: C, 27.20; H, 4.17; N, 10.19). Hereafter, this coordination polymer is referred to as "Compound 1."

[0145] [Method 1A] First, Zn-SBU was synthesized as a metal ion donor. This synthesis was carried out according to the following literature. Reference 1: Dell'Amico, DB et al. Inorg. Chem. Acta 2003, 350, 661-664 Reference 2: Dell'Amico, DB et al. Inorg. Chem. Acta 2006, 359 (10), 3371-3374

[0146] The synthesis scheme for Zn-SBU is shown below. Note that in the following scheme, the NCO2 moiety contained in Zn-SBU is derived from the raw material dimethylammonium dimethylcarbamate (Sigma-Aldrich; Merck Ltd.), and is not derived from gaseous CO2. [ka]

[0147] Next, PZ-CO2-DBU was synthesized as a bridging ligand source. In a glove box filled with Ar, DBU (1.196 mL, 8.00 mmol) was added dropwise to a 20 mL MeCN solution of HPZ (344.6 mg, 4.00 mmol) in a 50 mL round-bottom flask at 25 °C and atmospheric pressure. The flask was sealed with a rubber stopper and removed from the glove box. CO2 gas (>99.99%) was introduced into the flask at 25 °C and atmospheric pressure. Colorless crystals precipitated immediately at this stage. The reaction was complete after 12 h. Visual observation indicated that the reaction was nearly complete within 30 min to 1 h. The flask was purged with Ar and returned to the glove box. The crystals were filtered, washed with anhydrous MeCN under Ar, and dried in vacuum at 25 °C (82% yield). The synthesis scheme for PZ-CO2-DBU is shown below. [ka]

[0148] A 10 mL solution of PZ-CO2-DBU (168.2 mg, 0.30 mmol) in isopropanol was added to a 10 mL solution of Zn-SBU (90.4 mg, 0.10 mmol) in THF under Ar at 25 °C and atmospheric pressure. A white precipitate immediately formed, and the mixture was left overnight at 25 °C. Visual observation indicated that the reaction was nearly complete within 30 min to 1 h. The resulting precipitate was filtered, washed with isopropanol and THF under Ar, and dried in vacuo at 25 °C. Thus, a coordination polymer [Zn4O(PDC)3] was obtained (yield 94%). Hereafter, this coordination polymer is referred to as "Compound 1A."

[0149] [Method 1B] A 10 mL solution of PZ-CO2-DBU (336.4 mg, 0.60 mmol) in isopropanol was added to a 10 mL solution of Zn(OAc)2·2H2O (65.9 mg, 0.30 mmol) in DMF under Ar at 25 °C and atmospheric pressure. A white precipitate immediately formed, and the mixture was left overnight at 25 °C. Visual observation indicated that the reaction was nearly complete within 30 min to 1 h. The resulting precipitate was filtered, washed with DMF and isopropanol under Ar, and dried in vacuo at 25 °C. This afforded the coordination polymer [Zn4O(PDC)3] (85% yield). This coordination polymer is hereafter referred to as "Compound 1B."

[0150] [Method 1C] Carbon dioxide fixation was carried out in the same manner as in Method 1, except that DBU was not used. The reaction time, as determined by visual observation, was also nearly the same as in Method 1. In this way, a coordination polymer [Zn4O(PDC)3] was obtained (yield: 80%). Hereafter, this coordination polymer is referred to as "Compound 1C."

[0151] [Method 1D] Carbon dioxide fixation was carried out in the same manner as in Method 1, except that compressed air containing 400 ppm CO (>99.99%) was used instead of CO gas (>99.99%) and the reaction time was extended from overnight to 6 days. Visual observation indicated that the reaction was nearly complete within approximately 24 hours. In this way, a coordination polymer [ZnO(PDC)] was obtained (yield 61%). Hereafter, this coordination polymer is referred to as "Compound 1D."

[0152] Example 2 [Method 2] In a glove box filled with Ar, 30 mL of a DMF solution of Zn(OAc)2·2H2O (263.4 mg, 1.20 mmol) was mixed with 30 mL of an isopropanol solution of H2[SmPZ] (90.2 mg, 0.90 mmol) and DBU (540 μL, 3.6 mmol) in a 100 mL round-bottom flask at 25 °C and atmospheric pressure. The resulting clear solution was stirred for 3 minutes. The flask was sealed with a rubber stopper and removed from the glove box. In this way, the carbon dioxide fixation material of Example 2 was obtained.

[0153] Next, CO2 gas (>99.99%) was introduced into the flask at 25°C and atmospheric pressure. As a result, a white precipitate was immediately obtained (<10 seconds). The reaction mixture was stirred overnight while introducing CO2 gas, and the reaction was completed. Visual observation showed that the reaction was nearly completed within about 30 minutes to 1 hour. In this way, carbon dioxide fixation was carried out using the carbon dioxide fixation material of Example 2.

[0154] The flask was purged with Ar and returned to the glove box. The resulting precipitate was filtered off, washed with DMF and isopropanol under Ar, and dried in vacuo at 25 °C. Thus, the coordination polymer [ZnO(S-mPDC)] was obtained (yield 80%; C 21 H 30 NO 13 Calculated values for Zn4: C, 30.17; H, 3.62; N, 10.05. Found values: C, 29.28; H, 4.45; N, 9.89). Hereafter, this coordination polymer is referred to as "Compound 2."

[0155] [Method 2L] We attempted to scale up the carbon dioxide fixation reaction. In this example, the reaction was carried out in air without using a glove box. Furthermore, DBU was not used in this example.

[0156] Specifically, 1.5 L of a DMF solution of Zn(OAc)2·2H2O (52.7 g, 2.4 mol) was mixed with 1.5 L of an isopropanol solution of H2[SmPZ] (18.0 g, 1.8 mol) in a 5 L medium-sized bottle at 25°C and atmospheric pressure in air. The bottle was sealed with a rubber stopper. In this way, 2 L of the carbon dioxide fixation material of Example 1 was obtained.

[0157] Next, CO2 gas (>99.99%) was introduced into the bottle at 25°C and atmospheric pressure. As a result, a white precipitate was obtained (about 15 minutes). The reaction mixture was stirred for 3 days while introducing CO2 gas, and the reaction was completed. Visual observation showed that the reaction was almost complete within about 2 to 3 hours. In this way, carbon dioxide fixation was carried out using the carbon dioxide fixation material of Example 2L.

[0158] The resulting precipitate was filtered, washed with DMF and isopropanol in air, and dried under vacuum at 80 °C. In this way, the coordination polymer [ZnO(S-mPDC)] was obtained (approximately 50 g; yield 83%). This coordination polymer is hereafter referred to as "Compound 2L."

[0159] Example 3 [Method 3] Carbon dioxide fixation was carried out in the same manner as in Method 2, except that RmPZ was used instead of SmPZ. The reaction time, as determined by visual observation, was also almost the same as in Method 2. In this way, a coordination polymer [Zn4O(R-mPDC)3] was obtained (yield 84%; C 21 H 30 NO 13 Calculated values for Zn4: C, 30.17; H, 3.62; N, 10.05. Found values: C, 29.26; H, 4.08; N, 9.87). This coordination polymer is hereafter referred to as "Compound 3."

[0160] Example 4 [Method 4] Carbon dioxide fixation was carried out in the same manner as in Method 2, except that dmPZ was used instead of SmPZ. The reaction time, as determined by visual observation, was also almost the same as in Method 2. In this way, a coordination polymer [Zn4O(dmPDC)3] was obtained (yield 59%; C 24 H 36 NO 13 Calculated values for Zn4: C, 32.83; H, 4.13; N, 9.57. Found values: C, 32.46; H, 4.66; N, 9.49). Hereafter, this coordination polymer is referred to as "Compound 4."

[0161] Example 5 [Method 5] First, a methanol solution of bpy (250 mM) and HPZ (500 mM) was added to a methanol solution of Cu(NO) 3H0 (250 mM) at 25°C and atmospheric pressure while stirring. In this way, the carbon dioxide fixation material of Example 5 was obtained.

[0162] Next, CO2 gas (>99.99%) was introduced into the resulting reaction mixture at 25°C and atmospheric pressure while stirring. A precipitate formed within a few minutes after the introduction of CO2 gas. To complete the reaction, bubbling was continued for 12 hours, and a precipitate was obtained. Visual observation showed that the reaction was nearly complete within about 30 minutes to 1 hour. In this way, carbon dioxide fixation was carried out using the carbon dioxide fixation material of Example 5.

[0163] The resulting precipitate was filtered, washed with methanol, and then dried in the air. This resulted in the formation of a coordination polymer. This coordination polymer is hereafter referred to as "Compound 5."

[0164] Example 6 First, Zr-SBU was synthesized as a metal ion donor. This synthesis was carried out according to the following literature. Reference 3: G. Kickelbick et al., Chem. Ber., 1997, 130, 473

[0165] The synthesis scheme of Zr-SBU is shown below. [ka]

[0166] A DMF / ethanol solution (5 mM) of Zr-SBU was mixed with HPZ (30 mM), DBU (60 mM), and ammonium acetate (150 mM) under an Ar atmosphere at 25°C and atmospheric pressure to obtain a carbon dioxide fixation material according to Example 6.

[0167] Next, CO2 gas (>99.99%) was introduced into the resulting reaction mixture at 25°C and atmospheric pressure. A precipitate formed within a few minutes after the introduction of CO2 gas. To complete the reaction, bubbling was continued for 8 hours, and a precipitate was obtained. Visual observation showed that the reaction was nearly complete within about 30 minutes to 1 hour. In this way, carbon dioxide fixation was carried out using the carbon dioxide fixation material of Example 6. The white solid (coordination polymer) at this stage is referred to as "Compound 6."

[0168] The white solid was filtered off, washed with ethanol, and then dried in air. The resulting coordination polymer was designated "Compound 6'."

[0169] Example 7 [Method 7M] At 25°C and atmospheric pressure, a DMF solution (40 mM) of Cu(OAc)2·H2O was mixed with a methanol solution of PZ-CO2-DBU (40 mM) and dabco (20 mM). A precipitate formed within a few minutes of mixing. The resulting powder was filtered, washed with methanol, and dried. In this way, a coordination polymer with fixed carbon dioxide was obtained. This coordination polymer is hereafter referred to as "Compound 7M."

[0170] [Method 7E] Carbon dioxide fixation was carried out in the same manner as in Method 7M, except that an ethanol solution was used instead of a methanol solution. The rate of precipitation was also similar to that of Method 7M. Hereafter, the coordination polymer obtained in this manner is referred to as "Compound 7E."

[0171] [Method 7iP] Carbon dioxide fixation was carried out in the same manner as in Method 7M, except that an isopropanol solution was used instead of a methanol solution. The rate of precipitation was also similar to that of Method 7M. Hereafter, the coordination polymer obtained in this manner is referred to as "Compound 7iP."

[0172] Example 8 [Method 8] A DMF solution (40 mM) of Zn(OAc) 2H O was mixed with an isopropanol solution of DP (30 mM) and DBU (120 mM) under an Ar atmosphere at 25°C and atmospheric pressure to obtain the carbon dioxide fixation material of Example 8.

[0173] Next, CO2 gas (>99.99%) was introduced into the resulting reaction mixture at 25°C and atmospheric pressure. A precipitate formed within a few minutes after the introduction of CO2 gas. To complete the reaction, bubbling was continued for 12 hours, and a precipitate was obtained. Visual observation showed that the reaction was nearly complete within about 30 minutes to 1 hour. In this way, carbon dioxide fixation was carried out using the carbon dioxide fixation material of Example 8.

[0174] The resulting white solid was filtered off, washed with isopropanol, and then dried in air. The resulting coordination polymer is designated "Compound 8."

[0175] Example 9 (reference example) [Method 9] Under an Ar atmosphere, a 100 mM solution of pXDA in MeCN was added to a 10 mM solution of Zn-SBU in MeCN with stirring. The resulting reaction mixture was heated at 70 °C for 24 h. The resulting white solid was isolated by centrifugation, washed with MeCN, and then dried. The resulting coordination polymer is referred to as "Compound 9." Note that this method does not use CO2-containing gas, and CO2 fixation is not performed.

[0176] Example 10 [Method 10] First, a 500 mM solution of HPZ in methanol was added to a 250 mM solution of Cu(NO) 3H O in methanol at 25°C and atmospheric pressure with stirring. Thus, the carbon dioxide fixation material of Example 10 was obtained. The reaction mixture contained a purple precipitate. A portion of this precipitate was isolated and subjected to subsequent analysis. Hereinafter, this precipitate will be referred to as "Compound 10P."

[0177] Next, CO gas (>99.99%) was bubbled into the reaction mixture at 25°C and atmospheric pressure for 3 hours with stirring. As a result, the purple precipitate gradually changed to a blue precipitate. Visual observation showed that the reaction was nearly complete within about 30 minutes to 1 hour. In this way, carbon dioxide fixation was carried out using the carbon dioxide fixation material of Example 10.

[0178] The resulting blue powder was filtered, washed with methanol, and then dried. Thus, a coordination polymer was obtained. Hereafter, this coordination polymer is referred to as "Compound 10."

[0179] Example 11 [Method 11] First, a 500 mM solution of H2PZ in methanol was added to a 250 mM solution of MgNO3·6H2O in methanol at 25°C and atmospheric pressure while stirring. In this way, a carbon dioxide fixation material according to Example 11 was obtained.

[0180] Next, CO2 gas (>99.99%) was introduced into the resulting reaction mixture at 25°C and atmospheric pressure. A precipitate formed within a few minutes after the introduction of CO2 gas. To complete the reaction, bubbling was continued for 12 hours, and a precipitate was obtained. Visual observation showed that the reaction was nearly complete within about 30 minutes to 1 hour. In this way, carbon dioxide fixation was carried out using the carbon dioxide fixation material of Example 11.

[0181] The resulting powder was filtered, washed with methanol, and then dried in air. This gave a coordination polymer. This coordination polymer is hereafter referred to as "Compound 11."

[0182] Example 12 [Method 12] To a 30 mM solution of Zn(OAc) 2HO in methanol / DMF, 20 mM tpt and 120 mM DBU were added under stirring in air or under an Ar atmosphere at 25°C and atmospheric pressure. In this way, the carbon dioxide fixation material of Example 12 was obtained.

[0183] Next, CO2 gas (>99.99%) was introduced into the resulting reaction mixture at 25°C and atmospheric pressure. A precipitate formed within a few minutes after the introduction of CO2 gas. To complete the reaction, bubbling was continued for 12 hours, and a precipitate was obtained. Visual observation showed that the reaction was nearly complete within about 30 minutes to 1 hour. In this way, carbon dioxide fixation was carried out using the carbon dioxide fixation material of Example 12.

[0184] The resulting powder was filtered, washed with methanol, and then dried. In this way, a coordination polymer was obtained. Hereafter, this coordination polymer is referred to as "Compound 12."

[0185] Example 13 [Method 13] To a 30 mM solution of Cu(NO) 3H O in methanol / DMF, 20 mM tpt and 120 mM DBU were added under stirring in air or under an Ar atmosphere at 25°C and atmospheric pressure. In this way, the carbon dioxide fixation material of Example 13 was obtained.

[0186] Next, CO2 gas (>99.99%) was introduced into the resulting reaction mixture at 25°C and atmospheric pressure. A precipitate formed within a few minutes after the introduction of CO2 gas. To complete the reaction, bubbling was continued for 6 hours, and a precipitate was obtained. Visual observation showed that the reaction was nearly complete within about 30 minutes to 1 hour. In this way, carbon dioxide fixation was carried out using the carbon dioxide fixation material of Example 13.

[0187] The resulting powder was filtered, washed with methanol, and then dried. In this way, a coordination polymer was obtained. This coordination polymer is hereafter referred to as "Compound 13."

[0188] Example 14 [Method 14] A DMF solution (40 mM) of Zn(OAc) 2H O was mixed with an isopropanol solution of PDA (30 mM) and DBU (120 mM) under an Ar atmosphere at 25°C and atmospheric pressure to obtain the carbon dioxide fixation material of Example 14.

[0189] Next, CO2 gas (>99.99%) was introduced into the resulting reaction mixture at 25°C and atmospheric pressure. A precipitate formed within a few minutes after the introduction of CO2 gas. To complete the reaction, bubbling was continued for 24 hours, and a precipitate was obtained. Visual observation showed that the reaction was nearly complete within about 30 minutes to 1 hour. In this way, carbon dioxide fixation was carried out using the carbon dioxide fixation material of Example 14.

[0190] The resulting white powder was filtered, washed with isopropanol, and then dried. This gave a coordination polymer. This coordination polymer is hereafter referred to as "Compound 14."

[0191] Example 15 [Method 15] A DMF solution (50 mM) of Zn(OAc) 2H O was mixed with an ethanol solution of eda (100 mM) and DBU (400 mM) under an Ar atmosphere at 25°C and atmospheric pressure to obtain a carbon dioxide fixation material according to Example 15.

[0192] Next, CO2 gas (>99.99%) was introduced into the resulting reaction mixture at 25°C and atmospheric pressure. A precipitate formed within a few minutes after the introduction of CO2 gas. To complete the reaction, bubbling was continued for 12 hours, and a precipitate was obtained. Visual observation showed that the reaction was nearly complete within about 30 minutes to 1 hour. In this way, carbon dioxide fixation was carried out using the carbon dioxide fixation material of Example 15.

[0193] The resulting white powder was filtered, washed with ethanol, and then dried. This resulted in the formation of a coordination polymer. This coordination polymer is hereafter referred to as "Compound 15."

[0194] Example 16 [Method 16] A 35% HZ aqueous solution was mixed with an aqueous solution (50 mM) of MnCl2·4H2O at 25°C and atmospheric pressure, thus obtaining a carbon dioxide fixation material according to Example 16.

[0195] CO2 gas (>99.99%) was bubbled into the resulting pale orange suspension at 25°C and atmospheric pressure for 1 hour with stirring, yielding a colorless, transparent aqueous solution. Water was removed using an evaporator to obtain a white powder. In this way, carbon dioxide fixation was carried out using the carbon dioxide fixation material of Example 16. Hereinafter, the coordination polymer obtained in this way will be referred to as "Compound 16."

[0196] As described above, in Methods 1, 1C, 1D, 2, 2L, 3 to 6, 8, 11 to 16, the formation of a solid was observed by introducing a gas containing carbon dioxide into a homogeneous solution containing a metal ion donor and an amine. In Method 10, the formation of a new solid of a different color was observed by introducing a gas containing carbon dioxide into the solid obtained by the reaction of a metal ion donor with an amine. Furthermore, in Methods 1A, 1B, 7M, 7E, and 7iP, the formation of a solid was observed by mixing an amine solution into which a gas containing carbon dioxide had been introduced with a solution of a metal ion donor. These observations indicate that the introduction of a gas containing carbon dioxide directly or indirectly caused crosslinking between the metal ions and the carbamate ligands, resulting in the formation of a polymeric structure.

[0197] That is, as can be seen from the above Examples 1 to 8 and 10 to 16, by appropriately combining a metal ion donor with an amine configured to react with gaseous carbon dioxide to form a bridging ligand having at least one carbamate anion moiety, carbon dioxide fixation accompanied by the synthesis of a coordination polymer could be achieved under mild conditions and with high efficiency. In particular, as mentioned above, the fixation of carbon dioxide in Examples 1 to 8 and 10 to 16 could be achieved at room temperature and atmospheric pressure.

[0198] Furthermore, in the fixation of carbon dioxide in Examples 1 to 8 and 11 to 15, precipitation occurred immediately or within a very short time upon introduction of a gas containing carbon dioxide or upon mixing with an amine solution into which a gas containing carbon dioxide had been introduced. These observations suggest that in each of the above examples, fixation of carbon dioxide through the formation of a coordination polymer was achieved at a very high rate.

[0199] Furthermore, in particular, in Example 1D, carbon dioxide fixation from air was achieved. Also, in Example 2L, carbon dioxide fixation was achieved on a large scale in air within a short period of time. These examples suggest the high versatility of the carbon dioxide fixation material and fixation method according to the present invention.

[0200] Structure and physical property evaluation The structures and physical properties of the obtained compounds 1 to 16 were evaluated.

[0201] Examples 1 to 4 Powder X-ray diffraction (PXRD) measurements were performed on compounds 1 to 4. The PXRD measurements were performed using a Rigaku MiniFlex with a CuKα anode under an Ar atmosphere. The results are shown in Figure 1, along with the simulated pattern of MOF-5.

[0202] Figure 1 shows the PXRD patterns of compounds 1 to 4 and MOF-5. As can be seen from Figure 1, compounds 1 to 4 have the same periodic structure as MOF-5. Detailed crystal structure analysis of compounds 1 to 4 will be discussed in more detail later.

[0203] PXRD measurements were carried out on compounds 1, 1A, 1B and 1C, and the results are shown in FIG.

[0204] Figure 2 shows the PXRD patterns of compounds 1, 1A, 1B, and 1C. As can be seen from Figure 2, compounds 1, 1A, 1B, and 1C have similar periodic structures. This result suggests that various methods for fixing carbon dioxide are effective.

[0205] To confirm that PDC was formed from HPZ and CO, solid-state nuclear magnetic resonance (SSNMR) measurements were performed using a JNM-ECZ600R. Specifically, for compound 1, 1D 13 C CP-MAS (Cross-Polarization Magic Angle Spinning) SSNMR measurement and 2D 1 H- 13 C HETCOR (Heteronuclear Correlation) SSNMR measurements were performed. These measurements were performed under an Ar atmosphere. The results are shown in Figures 3 and 4.

[0206] Figure 3 shows the 1D structure of compound 1. 13 3 shows the C CP-MAS SSNMR spectrum. As shown in FIG. 3, this SSNMR spectrum had peaks at 43.6 ppm and 161.4 ppm. 13 The C peak is the carbamate anion (NCO - ) carbon atom peak (literature value) was in good agreement.

[0207] Figure 4 shows the 2D structure of compound 1. 1 H- 13 The C HETCOR SSNMR spectrum is shown in Figure 4. As is clear from Figure 4, the aliphatic proton (-CH2-) of piperazine correlated not only with the covalent carbon (43.6 ppm) but also with the carbon atom of the carbamate anion (161.4 ppm). This result suggests that PDC was formed in compound 1.

[0208] Zn in compound 1 2+ To investigate the coordination state of Zn, synchrotron X-ray absorption spectroscopy (XAS) measurements were performed. XAS measurements were performed at BL1.1W of the Synchrotron Light Research Institute in Thailand. Specifically, the Zn K-edge (9659 eV) spectrum was measured in fluorescence mode using a Si(111) double crystal monochromator. This measurement was performed under an Ar atmosphere. In this way, a Zn K-edge XANES (X-ray absorption near edge structure) spectrum was obtained. The results are shown in Figure 5.

[0209] Figure 5 shows the Zn K-edge XANES spectra of compound 1 and Zn-SBU. As shown in Figure 5, compound 1 had a spectrum almost identical to that of Zn-SBU. This suggests that compound 1 has a cluster structure similar to that of Zn-SBU.

[0210] To obtain further information about the first coordination shell of Zn, quantitative analysis was performed using Extended X-ray Absorption Fine Structure (EXAFS), and the results are shown in Figure 6.

[0211] Figure 6 shows the Zn K-edge EXAFS spectrum of compound 1. In Figure 6, the data points indicated by circles are experimental values, the solid line is a curve fit, and the dashed line indicates the fitting range (1.0 to 2.0 Å). From the results shown in Figure 6, the coordination number of Zn was determined to be 3.7 ± 0.2. This result suggests the presence of a tetrahedral Zn-O structure in compound 1.

[0212] FT-IR (Fourier transform infrared spectroscopy) measurements were performed on Compounds 1 to 4. IR measurements were performed using a Bruker Optics ALPHA. These measurements were performed under an Ar atmosphere. The results are shown in Figure 7.

[0213] Fig. 7 shows the FT-IR spectra of compounds 1 to 4. As can be seen from Fig. 7, compounds 1 to 4 have a peak intensity of 521 to 525 cm -1 This peak is well suited to the μ4-O-Zn stretching vibration peak of the [Zn4O(CO2)6] cluster.

[0214] As described above, the results of EXAFS and FT-IR measurements indicate the presence of [Zn4O(CO2)6] clusters in compounds 1 to 4.

[0215] To confirm the crystal structures of compounds 1 to 4, synchrotron PXRD measurements were performed. These measurements were performed using the BL02B2 beamline at the Super Photon Ring (Spring-8). Powder samples were sealed in glass tubes in an Ar-filled glove box. The SSNMR, XAS, and FT-IR measurements indicated the presence of [ZnO(CO)] and PDC in compound 1. Therefore, a Rietveld analysis was performed assuming a crystal model in which BDC in MOF-5 was replaced with PDC. The results are shown in Figures 8 to 10 and Table 3.

[0216] Figure 8 shows the results of the Rietveld analysis of compound 1. Figure 8 also shows the PXRD pattern of compound 1 and the simulation pattern of MOF-5. Table 3 shows the crystallographic data and refinement details of compounds 1 to 4. As shown in Figure 8 and Table 3, compound 1 was found to be isostructural with MOF-5. As shown in Table 3, compounds 2 to 4 were also found to be isostructural with MOF-5. The determined cell length of compound 1 (24.7739 Å) was shorter than the cell length of MOF-5 (25.6690 Å), which closely matched the difference between the PDC length (5.5 Å) and the BDC length (5.7 Å).

[0217] [Table 3]

[0218] Figures 9A to 9D show the packing structures of compounds 1 to 4, respectively. In each figure, the bridging ligands show static disorder. Figures 9A to 9D also show that compounds 1 to 4 have a porous structure similar to that of MOF-5.

[0219] Figure 10 shows the analysis results of the first Bragg peaks of compounds 1 to 4. The calculation results of FWHM (Full-Width-Half-Maximum) in Figure 10 are as follows: Compound 1:0.205° Compound 2:0.0406° Compound 3:0.0617° Compound 4:0.0540° It was found that Compound 2 exhibited the highest crystallinity.

[0220] From the crystal structures and composition formulas determined as above, the amount of CO2 introduced into Compounds 1 to 4 is Compound 1:33.3% by mass Compound 2: 31.6% by mass Compound 3: 31.6% by mass Compound 4: 30.1% by mass It was shown that the synthesis of compounds 1 to 4 resulted in highly efficient fixation of CO2.

[0221] Time-dependent PXRD measurements were performed to evaluate the air stability of compounds 1 and 2. The measurements were carried out at 25°C and 50% RH. The results are shown in Figure 11.

[0222] FIG. 11 shows the changes in the PXRD patterns of compounds 1 and 2 in air. In FIG. 11, "1-30 min" shows the PXRD pattern 30 minutes after compound 1 was taken out from an Ar atmosphere into air, "1-60 min" shows the PXRD pattern 60 minutes after compound 1 was taken out from an Ar atmosphere into air, and "2-60 min" shows the PXRD pattern 60 minutes after compound 1 was taken out from an Ar atmosphere into air. As can be seen from FIG. 11, compound 2 had superior stability to air or moisture compared to compound 1. This is thought to be due to the introduction of a hydrophobic methyl group in the bridging ligand of compound 2, which makes it difficult for HO molecules to diffuse into the pores.

[0223] To examine the morphology of compounds 1 to 4, scanning electron microscopy (SEM) was performed. This SEM observation was performed using a Hitachi SU5000. Measurements were performed by quickly observing the samples in air after activation. The results are shown in Figure 12.

[0224] Figures 12A to 12D show SEM images of compounds 1 to 4, respectively. As can be seen from Figures 12A to 12D, compound 1 exhibited aggregation of small particles (~60 nm), whereas compounds 2 (200-500 nm), 3 (200-500 nm), and 4 (200-300 nm) yielded cubic particles with minimal aggregation. This result is likely due to the steric hindrance of the methyl groups in the bridging ligands controlling the reaction kinetics of carbamate formation, resulting in excellent particle morphology and high crystallinity. The particle morphology of compounds 2 to 4 was similar to that of MOF-5 (>500 μm) obtained by hydrothermal synthesis.

[0225] To evaluate the scalability of the carbon dioxide fixation method described above, we compared compound 2L with compound 2. Specifically, we performed PXRD measurements of both compounds. The results are shown in Figure 13. As mentioned above, compound 2L is a coordination polymer obtained by a large-scale reaction in air using a non-dehydrated solvent.

[0226] Figure 13 shows the PXRD pattern of compound 2L. As can be seen from a comparison of Figure 13 with Figure 1, the PXRD pattern of compound 2L closely matches the PXRD pattern of compound 2. This result indicates that the fixation of carbon dioxide described above does not require severe dehydration conditions.

[0227] To confirm that the above-mentioned carbon dioxide fixation can be achieved using a gas with a low carbon dioxide content, compound 1D was compared with compound 1. Specifically, PXRD measurements were performed on both compounds. The results are shown in Figure 14. As mentioned above, compound 1D is a coordination polymer obtained by fixation of carbon dioxide using air (CO2 concentration: 400 ppm).

[0228] Figure 14 shows the PXRD pattern of compound 1D. As can be seen from a comparison of Figure 14 with Figure 1, the PXRD pattern of compound 1D was slightly less crystalline, but matched well with the PXRD pattern of compound 1. This result demonstrates that the fixation of carbon dioxide described above can be achieved even when using a gas with a low carbon dioxide content, such as air.

[0229] The thermal stability of Compounds 1 to 4 was evaluated. That is, TGA (Thermogravimetric Analysis) measurement was performed on Compounds 1 to 4. This TGA measurement was performed using a Rigaku Thermo plus TG 8121. The temperature range was 40°C to 500°C, and the heating rate was 10°C / min. This measurement was performed in an Ar atmosphere. The results are shown in Figure 15.

[0230] Figure 15 shows the TGA profiles of compounds 1 to 4 under an Ar atmosphere. As shown in Figure 15, compounds 1 to 4 have excellent thermal stability. The stabilization of the carbamate structure by coordination with metal ions will be discussed in more detail later.

[0231] The porosity of Compounds 1 to 4 was evaluated. Specifically, gas adsorption measurements were performed on Compounds 1 to 4. The gas adsorption measurements were performed using a BELSORP-max. Prior to the gas adsorption measurements, the samples were activated in vacuum at 80°C.

[0232] Figure 16 shows nitrogen adsorption isotherms at 77 K for compounds 1 to 4. In the adsorption isotherms shown below, the solid data points indicate the amount of adsorption during pressure increase, and the open data points indicate the amount of adsorption during pressure decrease. As can be seen from Figure 16, compounds 1 to 4 showed a sharp increase in the amount of nitrogen adsorption at low pressure. This suggests the presence of micropores in compounds 1 to 4.

[0233] The BET specific surface area obtained from the nitrogen adsorption isotherm at 77K is Compound 1:1525m 2 / g Compound 2:2366m 2 / g Compound 3:1943m 2 / g Compound 4:1270m 2 / g These values are calculated based on the reported BET specific surface area of MOF-5 (570–3800 m). 2 / g). The difference in BET specific surface area between compounds 1 to 4 and MOF-5 is thought to be due to the fact that PDC as a bridging ligand is slightly bulkier than BDC. The particularly large BET specific surface area of compound 2 is thought to be due to its high crystallinity.

[0234] Figure 17 shows the pore size distributions of compounds 1 to 4. These pore size distributions were calculated using the Non-Localized Density Functional Theory (NLDFT) model based on nitrogen adsorption isotherms. As can be seen from Figure 17, compounds 1 to 4 all had pores mainly around 1.2 nm. This value is in good agreement with the pore size of MOF-5 (1.4 nm).

[0235] Fig. 18 shows the hydrogen adsorption isotherms and isosteric adsorption heat curves versus hydrogen adsorption amount at 77 K for Compounds 1 to 4. As shown in Fig. 18, Compounds 1 to 4 exhibited a moderate hydrogen adsorption amount (0.9 to 1.4 mass%).

[0236] From the hydrogen adsorption isotherms at 77 K (FIG. 18) and 88 K (not shown), the zero-coverage adsorption enthalpies Q of compounds 1 to 4 were calculated. st was calculated by Virial fitting. As a result, Q st teeth, Compound 1:6.9kJ / mol Compound 2: 6.3kJ / mol Compound 3: 6.7kJ / mol Compound 4:7.4kJ / mol These values are the Q of MOF-5. stThe Q value of compound 4, which has the smallest pore size, was higher than that of st The Q values of compounds 1 to 4 were the highest. st Q of MOF-5 st The higher value is speculated to be due to the interaction of neighboring H2 molecules in the smaller pores.

[0237] 19 shows the carbon dioxide adsorption isotherms of Compounds 1 to 4 at 195 K. As shown in FIG. 19, the carbon dioxide adsorption amounts of Compounds 1 to 4 are Compound 1:353cm 3 / g Compound 2: 187cm 3 / g Compound 3: 429cm 3 / g Compound 4:296cm 3 / g All of the compounds had excellent carbon dioxide adsorption capacity. Among compounds 1 to 4, compound 3 showed the highest carbon dioxide adsorption capacity.

[0238] Figure 20 shows the high-pressure carbon dioxide adsorption isotherm of compound 3 at 298 K. This adsorption isotherm was saturated at 2.6 MPa, and the maximum adsorption amount of CO was 37.2 mass%. That is, the total CO content of compound 3 completely loaded with CO was 68.8 mass% (31.6 mass% as carbamate moieties and 37.2 mass% as adsorbent). This CO content was calculated based on the density of solid carbon dioxide (dry ice) (1.562 g / cm at 195 K and 0.1 MPa). 3 This is a high level, equivalent to one-third of the

[0239] The adsorption properties and CO2 contents of compounds 1 to 4 are summarized in Table 4.

[0240] [Table 4]

[0241] To investigate the effect of differences in synthesis methods on gas adsorption performance, gas adsorption measurements were carried out for compounds 1, 1A, 1B, and 1C. The results are shown in Figure 21.

[0242] 21 shows the nitrogen adsorption isotherms of compounds 1, 1A, 1B, and 1C at 77 K. As can be seen from FIG. 21, the BET specific surface areas increased in the order of compounds 1C<1B<1A<1.

[0243] Similarly, to investigate the effect of differences in synthesis methods on gas adsorption performance, gas adsorption measurements were performed on compound 2L. The results are shown in Figure 22.

[0244] Fig. 22 shows the nitrogen adsorption isotherm of compound 2L at 77 K. Comparing Fig. 22 with Fig. 16, it was found that the BET specific surface area was larger in the order of compound 2L<2.

[0245] Example 5 Powder X-ray diffraction (PXRD) measurement was carried out on Compound 5. The results are shown in FIG.

[0246] Figure 23 shows the PXRD pattern of compound 5. As can be seen from Figure 23, compound 5 had high crystallinity. Furthermore, the presence of peaks at low angles suggested the formation of a coordination polymer network. In particular, the PXRD pattern of compound 5 was similar to the PXRD pattern of Cu-JAST (not shown), suggesting that compound 5 has an isomorphous structure with Cu-JAST.

[0247] Gas adsorption measurements were carried out on Compound 5. The results are shown in FIG.

[0248] Figure 24 shows the nitrogen adsorption isotherm at 77 K and the carbon dioxide adsorption isotherm at 195 K for compound 5. The BET specific surface area calculated from the former is 18.5 m 2 / g, which indicated that Compound 5 had porosity.

[0249] TGA measurement was carried out on Compound 5. The results are shown in FIG.

[0250] Figure 25 shows the TGA-DTA profile of Compound 5. As shown in Figure 25, Compound 5 was found to be stable up to around 150°C and to have excellent thermal stability.

[0251] Solution NMR measurements were performed to confirm that compound 5 contained a carbamate ligand and an auxiliary ligand. The solution NMR measurements were performed at 25°C using a Bruker Avance III. Specifically, compound 5 was decomposed in DCl / DO (35%), and the resulting solution was subjected to NMR measurements in DMSO-d.

[0252] Figure 26 shows the solution NMR spectrum of compound 5. As can be seen from Figure 26, the presence of PZ and bpy was confirmed when compound 5 was decomposed. The molar ratio of PZ to bpy was 1:2. These observations suggest that compound 5 is indeed formed from two types of ligands and has a composition similar to that of Cu-JAST.

[0253] Example 6 Powder X-ray diffraction (PXRD) measurements were performed on compounds 6 and 6′ in air, and the results are shown in Figure 27 along with the simulated pattern of UiO-66.

[0254] Figure 27 shows the PXRD patterns of compounds 6 and 6' and UiO-66. As can be seen from Figure 27, although compounds 6 and 6' are not highly crystalline, their broad peaks at low angles are similar to those of UiO-66, suggesting the presence of a network structure similar to that of UiO-66.

[0255] Gas adsorption measurements were performed on compounds 6 and 6', and the results are shown in Figure 28.

[0256] Figure 28 shows the nitrogen adsorption isotherms of compounds 6 and 6' at 77 K. The BET specific surface area calculated from the latter is 18.6 m 2 / g, indicating that compound 6' has porosity. In particular, compound 6' exhibited hysteresis in the adsorption-desorption process, suggesting the presence of micropores.

[0257] FT-IR measurements were carried out on Compounds 6 and 6', and the results are shown in Figure 29 together with the measurement results for Compound 1 and Zr-SBU.

[0258] Figure 29 shows the FT-IR spectra of compounds 6 and 6', compound 1, and Zr-SBU. As shown in Figure 29, compounds 6 and 6' exhibited FT-IR spectra similar to that of compound 1. This result suggests that compounds 6 and 6', like compound 1, contain the carbamate ligand PDC. Compounds 6 and 6' also exhibited FT-IR spectra similar to that of Zr-SBU. This result suggests that compounds 6 and 6' retain the Zr cluster structure.

[0259] Compounds 6 and 6' were subjected to TGA measurement, and the results are shown in Figure 30.

[0260] Figure 30 shows the TGA profiles of compounds 6 and 6'. As shown in Figure 30, compounds 6 and 6' were found to have moderate thermal stability, with the internal solvent removed at around 130°C.

[0261] EXAFS measurements were performed on compound 6', and the results are shown in Figure 31, along with those for Zr-SBU.

[0262] Figure 31 shows the Zr K-edge EXAFS spectra of compound 6' and Zr-SBU. As shown in Figure 31, compound 6' had an EXAFS spectrum similar to that of Zr-SBU. This result indicated that compound 6' retained the same cluster structure as Zr-SBU.

[0263] Example 7 Powder X-ray diffraction (PXRD) measurements were performed on compounds 7M, 7E, and 7iP under an Ar atmosphere, and the results are shown in Figure 32 along with the simulated patterns of Cu-JAST-1.

[0264] Figure 32 shows the PXRD patterns of compounds 7M, 7E, and 7iP, as well as Cu-JAST-1. As can be seen from Figure 32, compounds 7E and 7iP were highly crystalline and had PXRD patterns similar to that of Cu-JAST-1. Although compound 7M was not highly crystalline, its broad peak at low angles was similar to that of Cu-JAST-1, suggesting the presence of a network structure similar to that of Cu-JAST-1.

[0265] Gas sorption measurements were performed on compound 7E, and the results are shown in Figure 33.

[0266] Figure 33 shows the carbon dioxide adsorption isotherm of compound 7E at 195 K. As shown in Figure 33, the carbon dioxide adsorption amount at 1 atm was 29 cm 3 / g, which indicates that compound 7E has porosity. Furthermore, the adsorption isotherm profile suggests that compound 7E has micropores, but the pore uniformity is not very high.

[0267] Example 8 Powder X-ray diffraction (PXRD) measurement was carried out under an Ar atmosphere for Compound 8. The results are shown in FIG.

[0268] Figure 34 shows the PXRD pattern of compound 8. As can be seen from Figure 34, although the crystallinity of compound 8 is not high, it shows a large peak at a low angle, suggesting the presence of long-range order due to the coordination polymer structure.

[0269] Gas adsorption measurements were carried out on compound 8. The results are shown in FIG.

[0270] Figure 35 shows the carbon dioxide adsorption isotherm of compound 8 at 195 K. As shown in Figure 35, the carbon dioxide adsorption amount at 1 atm was 52 cm 3 / g, which indicates that compound 8 has porosity. In addition, the profile of the adsorption isotherm shows a significant rise from low pressure, suggesting that compound 8 has a typical microporous structure.

[0271] TGA measurement was carried out on Compound 8. The results are shown in FIG.

[0272] Figure 36 shows the TGA profile of compound 8. As shown in Figure 36, the internal solvent was removed from compound 8 at around 120°C, indicating that compound 8 has moderate thermal stability.

[0273] Example 9 Powder X-ray diffraction (PXRD) measurements were performed on compound 9. This measurement was performed both before and after gas adsorption. For the measurement after gas adsorption, a sample was used that had been subjected to nitrogen adsorption measurement at 77 K and carbon dioxide adsorption measurement at 195 K. The results are shown in Figure 37.

[0274] Figure 37 shows the PXRD patterns of compound 9 before and after gas adsorption. As shown in Figure 37, compound 9 has high crystallinity, and its crystal structure remains unchanged even after gas adsorption. In addition, the presence of peaks at low angles suggests the formation of a coordination polymer network.

[0275] Gas adsorption measurements were carried out on Compound 9. The results are shown in Figures 38 and 39.

[0276] Figure 38 shows the nitrogen adsorption isotherm of compound 9 at 77 K. Figure 39 shows the carbon dioxide adsorption isotherm of compound 9 at 195 K. The BET specific surface area calculated from the former is 140 m 2 / g, and the CO2 adsorption capacity indicated by the latter is 48 cm 3 / g. That is, the results shown in Figures 38 and 39 indicate that Compound 9 has porosity. Furthermore, the adsorption profiles shown in Figures 38 and 39 suggest that Compound 9 has both micropores and mesopores.

[0277] FT-IR measurement was carried out under an Ar atmosphere for Compound 9. The results are shown in FIG. 40 together with the measurement results for Zn-SBU, which was also used as a raw material.

[0278] Figure 40 shows the FT-IR spectra of compound 9 and Zn-SBU. As shown in Figure 40, no peaks corresponding to ZnO clusters were detected in compound 9. This result suggests that compound 9 has a structure different from that of compound 1 and the like.

[0279] TGA measurement was carried out on Compound 9. The results are shown in Figure 41.

[0280] Figure 41 shows the TGA-DTA profile of Compound 9. As shown in Figure 41, Compound 9 was found to be stable up to around 200°C and to have excellent thermal stability.

[0281] Example 10 Powder X-ray diffraction (PXRD) measurements were carried out on compound 10 and its precursor, compound 10P, and the results are shown in Figures 42 and 43.

[0282] Figure 42 shows the PXRD pattern of compound 10. As can be seen from Figure 42, compound 10 had high crystallinity. In addition, the presence of peaks at low angles suggested the formation of a coordination polymer network.

[0283] Figure 43 shows the PXRD patterns of compound 10, a coordination polymer with a similar structure, and compound 10P. This coordination polymer with a similar structure is a compound described in the following document 4, and Cu 2+This is a coordination polymer containing a paddlewheel unit and 1,4-cyclohexanedicarboxylic acid. As shown in Figure 43, compound 10 is presumed to have a one-dimensional chain structure similar to this coordination polymer. Furthermore, a comparison of the PXRD patterns of compound 10 and compound 10P revealed that they have completely different structures. Document 4: H. Kumagai et al. Inorg. Chem. 2007, 46, 5949

[0284] To trace the transformation from compound 10P to compound 10, FT-IR measurements were performed on both compounds, and the results are shown in Figure 44.

[0285] Figure 44 shows the FT-IR spectra of Compound 10 and Compound 10P. As can be seen from Figure 44, as Compound 10P changes to Compound 10, a peak corresponding to NH (3600 cm -1 The peak corresponding to C=O (around 1528 cm) disappeared. ー1 A new formation had been formed nearby.

[0286] The following mechanism is presumed based on the differences in the PXRD patterns and FT-IR spectra of Compound 10 and Compound 10P, as well as the observations made during synthesis.

[0287] In the first step, a Cu salt reacts with HPZ to form a mononuclear or polymeric complex, resulting in the formation of a purple precipitate (compound 10P). This precipitate is characterized by the presence of NH, for example, [Cu(HPZ) x It is thought to have a composition such as (NO3)2.

[0288] In the second step, the introduction of CO2-containing gas cleaved the Cu-N bond, forming a carbamate anion moiety and a Cu-O bond, resulting in the formation of a blue precipitate (compound 10). Based on the presence of the C=O mentioned above, this precipitate is thought to have a composition such as [Cu(PDC)].

[0289] The color change accompanying the conversion of compound 10P to compound 10 is due to the change in the Cu 2+ This suggests a transformation of the electronic structure of

[0290] Gas adsorption measurements were carried out on compound 10. The results are shown in Figure 45.

[0291] Figure 45 shows the nitrogen adsorption isotherm at 77 K and the carbon dioxide adsorption isotherm at 195 K for compound 10. In Figure 45, the amount of adsorbed nitrogen is indicated by a circle, and the amount of adsorbed carbon dioxide is indicated by a square. The BET specific surface area calculated from the former is 4.78 m 2 / g, and the CO2 adsorption capacity indicated by the latter is 1.6 cm 3 / g, that is, Compound 10 did not have porosity.

[0292] Example 11 Powder X-ray diffraction (PXRD) measurement was carried out on compound 11. The results are shown in FIG.

[0293] Figure 46 shows the PXRD pattern of compound 11. As can be seen from Figure 46, compound 11 was highly crystalline. In addition, the presence of peaks at low angles suggested the formation of a coordination polymer network.

[0294] Gas adsorption measurements were carried out on Compound 11. The results are shown in Figures 47 and 48.

[0295] Figure 47 shows the nitrogen adsorption isotherm of compound 11 at 77 K. Figure 48 shows the carbon dioxide adsorption isotherm of compound 11 at 195 K. The BET specific surface area calculated from the former is 3.57 m. 2 / g, and the CO2 adsorption capacity indicated by the latter is 8 cm 3 / g. That is, the results shown in Figures 47 and 48 indicate that Compound 11 does not have porosity.

[0296] TGA measurement was carried out on Compound 11. The results are shown in Figure 49.

[0297] Figure 49 shows the TGA-DTA profile of compound 11. As shown in Figure 49, after the internal solvent was removed at around 90°C, compound 11 showed no weight loss up to around 300°C, indicating that it has excellent thermal stability.

[0298] Example 12 Powder X-ray diffraction (PXRD) measurements were performed on compound 12 both under Ar and in air, and the results are shown in Figure 50 along with the simulated pattern of MOF-177.

[0299] Figure 50 shows the PXRD patterns of compound 12 and MOF-177. As can be seen from Figure 50, although compound 12 is not highly crystalline, its broad peak at low angles is similar to that of MOF-177, suggesting the presence of a network structure similar to that of MOF-177. It was also found that compound 12 retains its structure even in air.

[0300] FT-IR measurement was carried out on Compound 12. The results are shown in FIG. 51 together with the measurement results on Compound 1.

[0301] Figure 51 shows the FT-IR spectra of Compound 12 and Compound 1. As can be seen from Figure 51, Compound 12 had an FT-IR spectrum similar to that of Compound 1. This suggests that Compound 12 retains ZnO clusters and also has carbamate ligands.

[0302] TGA measurement was carried out on compound 12. The results are shown in Figure 52.

[0303] Figure 52 shows the TGA-DTA profile of compound 12. As shown in Figure 52, after the internal solvent was removed at around 140°C, compound 12 showed no weight loss up to around 250°C, indicating that it has excellent thermal stability.

[0304] Example 13 Powder X-ray diffraction (PXRD) measurements were performed on compound 13 both under an Ar atmosphere and in air, and the results are shown in Figure 53.

[0305] Figure 53 shows the PXRD pattern of compound 13. As can be seen from Figure 53, compound 13 was highly crystalline. The presence of peaks at low angles suggested the formation of a coordination polymer network. It was also found that compound 13 maintained its structure even in air.

[0306] Example 14 Powder X-ray diffraction (PXRD) measurements were performed on compound 14. The results are shown in FIG.

[0307] Figure 54 shows the PXRD pattern of compound 14. As can be seen from Figure 54, compound 14 was amorphous.

[0308] Gas adsorption measurements were carried out on compound 14. The results are shown in Figure 55.

[0309] Figure 55 shows the carbon dioxide adsorption isotherm of compound 14 at 195 K. The results shown in Figure 55 indicate that the CO adsorption capacity is 20.5 cm 3 / g. That is, the results shown in Figure 55 indicate that compound 14 has porosity.

[0310] FT-IR measurement was carried out on compound 14. The results are shown in FIG.

[0311] Figure 56 shows the FT-IR spectrum of compound 14. As shown in Figure 56, compound 14 exhibited peaks corresponding to NH and C=O. This result suggested that compound 14 had a structure represented by NH(CO)CHCHCHNH(CO).

[0312] TGA measurement was carried out on compound 14. The results are shown in Figure 57.

[0313] Figure 57 shows the TGA-DTA profile of compound 14. As shown in Figure 57, compound 14 did not show a significant weight loss up to around 120°C, indicating that it has moderate thermal stability.

[0314] Example 15 Powder X-ray diffraction (PXRD) measurements were performed on compound 15. The results are shown in FIG.

[0315] Figure 58 shows the PXRD pattern of compound 15. As can be seen from Figure 58, compound 15 was highly crystalline. In addition, the presence of peaks at low angles suggested the formation of a coordination polymer network.

[0316] Gas adsorption measurements were carried out on compound 15. The results are shown in Figure 59.

[0317] Figure 59 shows the carbon dioxide adsorption isotherm of compound 15 at 195 K. The results shown in Figure 59 indicate that the CO adsorption capacity is 9.4 cm 3 / g.

[0318] TGA measurement was carried out on Compound 15. The results are shown in Figure 60.

[0319] Figure 60 shows the TGA-DTA profile of compound 15. As shown in Figure 60, compound 15 was found to have moderate thermal stability.

[0320] Example 16 Powder X-ray diffraction (PXRD) measurements were performed on compound 16. The results are shown in Figure 61.

[0321] Figure 61 shows the PXRD pattern of compound 16. As can be seen from Figure 61, compound 16 was highly crystalline. In addition, the presence of peaks at low angles suggested the formation of a coordination polymer network.

[0322] Gas adsorption measurements were carried out on compound 16. The results are shown in Figure 62.

[0323] Figure 62 shows the carbon dioxide adsorption isotherm of compound 16 at 195 K. The results shown in Figure 62 indicate that the CO2 adsorption capacity is 1.3 cm 3 / g.

[0324] TGA measurement was carried out on compound 16. The results are shown in Figure 63.

[0325] Figure 63 shows the TGA-DTA profile of compound 16. As shown in Figure 63, compound 16 exhibited a gradual weight loss, indicating that it has moderate thermal stability.

[0326] Representative information for each of the above examples is summarized in Table 5 below. As shown in Table 5 below, carbon dioxide fixation was achieved in Examples 1 to 8 and 10 to 16. Crystalline coordination polymers were obtained in Examples 1 to 13, 15, and 16. In particular, coordination polymers with high crystallinity were obtained in Examples 1 to 5, 7, 9 to 11, 13, and 15 and 16. Furthermore, porous coordination polymers were obtained in Examples 1 to 9 and 14.

[0327] [Table 5]

[0328] Stabilization of carbamate structures by coordination to metal ions Finally, we investigated experimentally and numerically that the carbamate anion moiety in the bridging ligand is stabilized by coordination with the metal ion.

[0329] As a control compound, PZ-CO2 was synthesized according to the following literature 5. Reference 5: Sim, J. et al. Bull. Korean Chem. Soc. 2016, 37 (11), 1854-1857.

[0330] The synthesis scheme of PZ-CO2 is shown below. [ka]

[0331] To demonstrate the stabilization of the carbamate structure by coordination with metal ions, TGA measurements were performed on compound 2 and PZ-CO2. The measurements were performed in both air and Ar atmosphere. The results are shown in Figure 64.

[0332] Figure 64 shows the TGA profiles of Compound 2 and PZ-CO2 in air and under Ar atmosphere. As shown in Figure 64, Compound 2 had superior thermal stability compared to PZ-CO2.

[0333] Temperature-programmed desorption (TPD) measurements of CO were performed on Compound 2 and PZ-CO. The TPD measurements were performed using a MicrotracBEL BELCAT. The temperature range was 30°C to 500°C, and the heating rate was 10°C / min. The measurements were performed using 10 mg of each sample under an Ar gas flow (30 mL / min). The results are shown in Figure 65, along with the TGA results.

[0334] Figure 65 shows the TGA and TPD profiles of Compound 2 and PZ-CO2 under an Ar atmosphere. As shown in Figure 65, Compound 2 had a higher CO2 release temperature and superior thermal stability compared to PZ-CO2.

[0335] Next, we performed theoretical calculations to evaluate the binding energy between metal ions and the carbamate anion moiety. 2+The binding energy between PDC and PDC was investigated by density functional theory (DFT) calculations, which were performed using the Fritz Haber Institute ab initio molecular simulations (FHI-aims) package version 171221_1.

[0336] The calculation model for compound 1 was the [Zn4O(OAc)5]-PDC-[Zn4O(OAc)5] structure, in which two [Zn4O(CO2)6] clusters capped with acetate anions are connected by a single PDC. 2+ The total energy of the model was calculated by varying the distance between the oxygen atom of PDC and the carboxyl group in the range of 1.51 Å to 4.43 Å, and the results are shown in Figures 66 and 67.

[0337] Figure 66 shows the potential energy as a function of the Zn-O distance in the model structures of compound 1 and MOF-5. Figure 67 shows the model structure of compound 1 corresponding to the maximum and minimum values of potential energy. As can be seen from Figures 66 and 67, the potential energy was minimum when the Zn-O distance was 1.96 Å and maximum when it was 4.45 Å. This result indicates that the potential energy decreases when the carbamate anion site of PDC coordinates with Zn.

[0338] The above TGA and TPD profiles and DFT calculations suggest that in the carbon dioxide fixation material and fixation method according to the present invention, and the porous coordination polymer and production method thereof according to the present invention, the carbamate anion moiety in the bridging ligand is thermodynamically stabilized by coordination with a metal ion.

Claims

1. a metal ion donor; Amines as bridging ligand precursors Including, the amine is configured to react with gaseous carbon dioxide to form a bridging ligand having at least one carbamate anion moiety; the bridging ligand is configured to react with the metal ion donor to form a coordination polymer in which a plurality of the metal ions are linked by the bridging ligand; Carbon dioxide fixer.

2. 2. The carbon dioxide fixing material according to claim 1, wherein the amine has two or more primary amine groups or secondary amine groups and is configured to react with gaseous carbon dioxide to form a bridging ligand having two or more carbamate anion sites.

3. The amine is represented by the following general formula (1A): 【Chemical 1】 During the ceremony, R １ is a hydrogen atom, an alkyl group, or R １ and A form a heterocycle together with the nitrogen atom between A and A, A is a single bond or a linking group containing at least one carbon atom; Q is a group configured to form an anionic site capable of coordinating with the metal ion; The carbon dioxide fixing material according to claim 1 or 2.

4. R １ is a hydrogen atom, or R １ The carbon dioxide fixation material according to claim 3, wherein Q, together with the nitrogen atom between Q and A, forms a heterocycle having two or less substituents other than Q.

5. The amine is represented by the following general formula (2A): 【Chemistry 2】 During the ceremony, R １ is a hydrogen atom, an alkyl group, or R １ and A form a heterocycle together with the nitrogen atom between A and A, A is a single bond or a linking group containing at least one carbon atom; R ２ is a hydrogen atom, an alkyl group, or R ２ and A together with the nitrogen atom between A and R ２ and the nitrogen atom between A and R １ and the nitrogen atom between A and R １ together with The carbon dioxide fixing material according to any one of claims 1 to 4.

6. R ２ is a hydrogen atom, or R ２ The nitrogen atom between A and NHR together with A １ or forms a heterocyclic ring having two or less substituents other than the group containing R ２ and the nitrogen atom between A and R １ and the nitrogen atom between A and R １ The carbon dioxide fixation material according to claim 5, wherein the carbon dioxide fixation material forms a heterocycle having two or less substituents together with the carbon dioxide fixation material.

7. 7. The carbon dioxide fixing material according to claim 1, wherein the metal ion donor is configured to donate at least one metal ion selected from the group consisting of zinc ions, copper ions, zirconium ions, magnesium ions, iron ions, cobalt ions, chromium ions, and aluminum ions.

8. The carbon dioxide fixing material according to claim 1 , wherein the carbon dioxide content in the coordination polymer is 20 mass % or more.

9. The coordination polymer has a BET specific surface area of 10 m as calculated from a nitrogen adsorption isotherm at 77 K. ２ / g or more, or the carbon dioxide adsorption capacity at 195 K and 1 atm is 15 cm ３ The carbon dioxide fixation material according to claim 1 , which is a porous coordination polymer having a solubility of 0.01% by mass % (STP) / g or more.

10. The carbon dioxide fixation material according to claim 1 , wherein the formation of the coordination polymer is carried out under atmospheric pressure and room temperature conditions or milder conditions.

11. providing a formulation including a metal ion donor and an amine configured to react with gaseous carbon dioxide to form a bridging ligand having at least one carbamate anion moiety; supplying a gas containing carbon dioxide to the mixture to produce a coordination polymer in which a plurality of the metal ions are linked by the bridging ligand; A method for fixing carbon dioxide containing

12. providing a gas comprising carbon dioxide to an amine to form a bridging ligand having at least one carbamate anion moiety; reacting the bridging ligand with a metal ion donor to produce a coordination polymer in which a plurality of the metal ions are linked by the bridging ligand; A method for fixing carbon dioxide containing

13. 13. The method for fixation of carbon dioxide according to claim 11 or 12, wherein the coordination polymer is produced under atmospheric pressure and room temperature conditions or milder conditions.

14. 14. The method for fixation of carbon dioxide according to claim 11, wherein the gas containing carbon dioxide is air.

15. A plurality of metal ions; a plurality of bridging ligands each having at least one carbamate anion moiety; Including, at least a portion of the metal ions are coordinated by the carbamate anion moieties, thereby connecting the metal ions and the bridging ligands to each other to form a porous framework; The BET specific surface area calculated from the nitrogen adsorption isotherm at 77 K is 10 m ２ / g or more, or the carbon dioxide adsorption capacity at 195 K and 1 atm is 15 cm ３ (STP) / g or more; Porous coordination polymer.

16. 16. The porous coordination polymer of claim 15, wherein the bridging ligand has two or more carbamate anion sites.

17. The bridging ligand is represented by the following general formula (1B): 【Chemistry 3】 During the ceremony, R １ is a hydrogen atom, an alkyl group, or R １ and A form a heterocycle together with the nitrogen atom between A and A, A is a single bond or a linking group containing at least one carbon atom; Q － is an anionic moiety capable of coordinating to the metal ion; The porous coordination polymer according to claim 15 or 16.

18. The bridging ligand is represented by the following general formula (2B): 【Chemistry 4】 During the ceremony, R １ is a hydrogen atom, an alkyl group, or R １ and A form a heterocycle together with the nitrogen atom between A and A, A is a single bond or a linking group containing at least one carbon atom; R ２ is a hydrogen atom, an alkyl group, or R ２ and A together with the nitrogen atom between A and R ２ and the nitrogen atom between A and R １ and the nitrogen atom between A and R １ together with The porous coordination polymer according to any one of claims 15 to 17.

19. providing a formulation including a metal ion donor and an amine configured to react with gaseous carbon dioxide to form a bridging ligand having at least one carbamate anion moiety; providing a gas comprising carbon dioxide to the formulation; A method for producing a porous coordination polymer comprising:

20. providing a gas comprising carbon dioxide to an amine to form a bridging ligand having at least one carbamate anion moiety; reacting the bridging ligand with a metal ion donor; A method for producing a porous coordination polymer comprising:

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