Three-dimensional network structured metal complex crystal and method for determining molecular structure of organic compound using same

Abstract

The present invention provides a novel metal complex crystal which has regularly arranged vacancies and is capable of forming an X-ray structure analysis sample by fixing an organic compound in the vacancies.　A metal complex crystal according to the present disclosure is composed of a metal ion and a ligand, and the ligand includes a carboxylic acid-based ligand (c) and a pyridine-based ligand (p) in a combination selected from among [I]-[IV] described below. [I] compound (c1) and compound (p1) [II] compound (c1) and compound (p2) [III] compound (c2) and compound (p2) [IV] compound (c2) and compound (p3)

Description

Three-dimensional network structure metal complex crystal and method for determining molecular structure of organic compound using the same

[0001] The present disclosure relates to a novel three-dimensional network-structure metal complex crystal and a method for determining the molecular structure of an organic compound using the three-dimensional network-structure metal complex crystal. This disclosure claims priority to Japanese Patent Application No. 2023-202762, filed in Japan on November 30, 2023, the contents of which are incorporated herein by reference.

[0002] As a method for determining the molecular structure of an organic compound, single crystal X-ray structural analysis, that is, a method in which a single crystal of an organic compound is subjected to X-ray structural analysis, is known. This method is very useful because it allows accurate determination of the molecular structure of an organic compound if a high-quality single crystal can be prepared.

[0003] However, when the amount of organic compound is so small that a sufficient amount of single crystal cannot be obtained, it is difficult to determine the molecular structure by this method. Also, there are organic compounds that are difficult to crystallize, and the molecular structure of such organic compounds cannot be determined by this method.

[0004] Therefore, the crystalline sponge method has been developed, which allows the molecular structure of organic compounds to be determined by X-ray structural analysis without undergoing a crystallization process (see, for example, Patent Document 1). In the crystalline sponge method, a metal complex crystal with regularly aligned pores is used as a material for forming an X-ray structural analysis sample (or crystalline sponge, or host). Then, an organic compound whose molecular structure is desired to be determined is impregnated and fixed as guest molecules into the pores of the host metal complex crystal together with a solvent. The regularly aligned organic compound is used as a X-ray structural analysis sample (i.e., a sample to be subjected to X-ray structural analysis). The resulting X-ray structural analysis sample is then irradiated with X-rays to determine the molecular structure of the organic compound.

[0005] International Publication No. 2014 / 038220

[0006] However, the metal complex crystal described in Patent Document 1 had a problem of a low success rate, with only a probability of determining the molecular structure of an organic compound being about 30%. Furthermore, while the success rate of molecular structure determination could be increased by optimizing conditions such as the type of solvent used when impregnating the metal complex crystal with the organic compound and the impregnation temperature depending on the type of organic compound, the metal complex crystal has low solvent resistance and dissolves in medium- to high-polarity solvents, resulting in a problem of a limited number of solvents that can be used. Furthermore, since the pores of the metal complex crystal have a hydrophobic environment, it is difficult to retain hydrophilic organic compounds within the pores of the metal complex crystal, making it difficult to determine the molecular structure of hydrophilic organic compounds using the metal complex crystal.

[0007] Therefore, an object of the present disclosure is to provide a novel metal complex crystal having regularly aligned vacancies, which can be used to form an X-ray structural analysis sample by fixing an organic compound in the vacancies. Another object of the present disclosure is to provide a novel metal complex crystal having regularly aligned vacancies, which can be used as an X-ray structural analysis sample to determine the molecular structures of various organic compounds with a high probability by fixing an organic compound in the vacancies. Another object of the present disclosure is to provide a method for determining the molecular structure of an organic compound using the metal complex crystal.

[0008] The present inventors conducted extensive research to solve the above-mentioned problems and discovered the following: In order to determine the molecular structure of an organic compound, it is necessary to regularly align the organic compound. However, in the metal complex crystal described in Patent Document 1, the organic compound is immobilized in the pores by relatively weak intermolecular interactions such as Π-Π interactions and σ-Π interactions, and therefore the probability of retaining the organic compound in the pores is low. Furthermore, because the metal complex crystal described in Patent Document 1 has a weak ability to regularly align organic compounds, it was found that when the metal complex crystal is used as a crystalline sponge, the probability of determining the molecular structure is low. On the other hand, it has been discovered that amide groups can strongly interact with various functional groups through hydrogen bonds, and that when a specific ligand having an amide group is coordinated to a metal ion, a metal complex crystal having regularly aligned pores can be obtained, that the metal complex crystal obtained in this manner can accommodate organic compounds in the regularly aligned pores with a high probability, and that the accommodated organic compounds are firmly held in an oriented state, and that if an organic compound is incorporated into the pores of the metal complex crystal and fixed, and the resulting crystal is used as a sample for X-ray structural analysis, the molecular structure can be determined with a high probability by X-ray diffraction. The present disclosure has been completed based on these findings.

[0009] That is, the present disclosure provides a metal complex crystal comprising a metal ion and a ligand coordinated to the metal ion, the metal complex crystal having a three-dimensional network structure with regularly aligned pores, the ligand including a carboxylic acid-based ligand (c) and a pyridine-based ligand (p), the carboxylic acid-based ligand (c) and the pyridine-based ligand (p) being a combination selected from the following [I] to [IV]: [I] A compound represented by the following formula (c1) and a compound represented by the following formula (p1): [II] A compound represented by the following formula (c1) and a compound represented by the following formula (p2): [III] A compound represented by the following formula (c2) and a compound represented by the following formula (p2): [IV] A compound represented by the following formula (c2) and a compound represented by the following formula (p3): (In the formula, Ar １ , Ar ２ are the same or different and represent aromatic rings; R １, R ２ are the same or different and each represents a group selected from a single bond, a divalent hydrocarbon group, a divalent heterocyclic group, and a divalent group formed by linking two or more of the above groups. １ , L ２ are the same or different and represent a single bond or a linking group.

[0010] The present disclosure also provides the metal complex crystal, wherein the metal ion is selected from zinc ions, iron ions, cobalt ions, nickel ions, copper ions, and silver ions.

[0011] The present disclosure also provides the metal complex crystal, which is a metal complex crystal for use in analyzing the molecular structure of an organic compound.

[0012] The present disclosure also provides the metal complex crystal, wherein the organic compound is an organic compound having a functional group having an interaction with a CO group, an NH group, or a CONH group.

[0013] The present disclosure also provides the metal complex crystal, wherein the organic compound has a log P value of −5 or more and 7 or less.

[0014] The present disclosure also provides the metal complex crystal, wherein the organic compound is an organic compound having at least one functional group selected from a substituted or unsubstituted amino group, a carboxyl group, an active methylene group, a nitrile group, a ketone group, an aldehyde group, an ester group, an ether group, an amide group, a hydroxy group, a halogen group, and a sulfonamide group.

[0015] The present disclosure also provides a method for determining the molecular structure of an organic compound (X), comprising the following steps 1 and 2: Step 1: impregnating the metal complex crystal with the organic compound (X) to fix the organic compound (X) in the pores of the metal complex crystal; and Step 2: irradiating the metal complex crystal with the fixed organic compound (X) with X-rays, and analyzing the obtained diffraction data to determine the molecular structure of the organic compound (X).

[0016] The metal complex crystal of the present disclosure has large, regularly aligned pores. Furthermore, the metal complex crystal contains amide groups, which have the property of forming hydrogen bonds with various functional groups. Therefore, when an organic compound is infiltrated into the pores of the metal complex crystal, the organic compound can be immobilized with a high probability and strength in a regularly aligned state. Furthermore, because the metal complex crystal contains amide groups, the interior of the pores exhibits a hydrophilic environment, allowing hydrophilic organic compounds to be immobilized within the pores. Furthermore, the metal complex crystal has excellent solvent resistance and can maintain its crystalline structure in various solvents.

[0017] Therefore, by using the metal complex crystal as a host, even if the amount of organic compound (X) as a guest molecule is too small to form a single crystal or the compound cannot be formed into a single crystal, the organic compound (X) can be regularly aligned and fixed within the metal complex crystal and subjected to X-ray structural analysis, thereby easily and with a high probability of determining its molecular structure. Because of the above-mentioned properties, the metal complex crystal is highly versatile as a host in the crystalline sponge method. More specifically, the metal complex crystal is highly versatile as a material for forming samples for X-ray structural analysis of organic compounds (X) (especially hydrophilic organic compounds).

[0018] FIG. 1 is a schematic diagram showing the crystal structure of metal complex crystal 1 obtained in an example. FIG. 2 is a schematic diagram showing the crystal structure of metal complex crystal 3 obtained in a comparative example. FIG. 3 is a schematic diagram showing a state in which 4-methylacetophenone is fixed to metal complex crystal 1 by hydrogen bonding. FIG. 4 is a schematic diagram showing a state in which 1,3-dimethyl-2-imidazolidinone is fixed to metal complex crystal 1 by hydrogen bonding. FIG. 5 is a schematic diagram showing a state in which methyl 2-furancarboxylate is fixed to metal complex crystal 1 by hydrogen bonding. FIG. 6 is a schematic diagram showing a state in which 2,4-dimethoxybenzyl alcohol is fixed to metal complex crystal 1 by hydrogen bonding. FIG. 7 is a schematic diagram showing a state in which 2-naphthalenecarboxylic acid is fixed to metal complex crystal 1 by hydrogen bonding. FIG. 8 is a schematic diagram showing a state in which zonisamide is fixed to metal complex crystal 1 by hydrogen bonding. FIG. 9 is a schematic diagram showing a state in which 2,4,6-trimethylaniline is fixed to metal complex crystal 1 by hydrogen bonding. FIG. 10 is a schematic diagram showing a state in which bergapten is fixed to metal complex crystal 1 by hydrogen bonding. 1 is a schematic diagram showing a state in which two molecules of bergapten are fixed by π-π interactions to a metal complex crystal 1. FIG. 2 is a schematic diagram showing a state in which 1-aminopyrene is fixed by π-π interactions to a metal complex crystal 1.

[0019] [Metal Complex Crystal] The metal complex crystal of the present disclosure is a metal complex crystal composed of a metal ion and a ligand coordinated to the metal ion. The metal complex crystal is a microporous metal complex crystal having a three-dimensional network structure with regularly arranged pores.

[0020] The metal ions are not particularly limited as long as they can form a three-dimensional network structure by coordinate bonding with a ligand described below, and examples thereof include ions of metals in Groups 8 to 12 of the periodic table, such as zinc ions, iron ions, cobalt ions, nickel ions, copper ions, and silver ions. Among these, divalent metal ions are preferred, and zinc ions and / or cobalt ions are particularly preferred, in that they can give a three-dimensional network structure metal complex crystal having large pores.

[0021] The ligand includes at least one type of carboxylic acid-based ligand (c) and at least one type of pyridine-based ligand (p). The combination of the carboxylic acid-based ligand (c) and the pyridine-based ligand (p) is a combination selected from the following [I] to [IV]. [I] A compound represented by the following formula (c1) and a compound represented by the following formula (p1): [II] A compound represented by the following formula (c1) and a compound represented by the following formula (p2): [III] A compound represented by the following formula (c2) and a compound represented by the following formula (p2): [IV] A compound represented by the following formula (c2) and a compound represented by the following formula (p3): (In the formula, Ar １ , Ar ２ are the same or different and represent aromatic rings; R １ , R ２ are the same or different and each represents a group selected from a single bond, a divalent hydrocarbon group, a divalent heterocyclic group, and a divalent group formed by linking two or more of the above groups. １ , L ２ are the same or different and represent a single bond or a linking group.

[0022] Ar １ , Ar ２ The aromatic ring in the formula (I) includes an aromatic hydrocarbon ring and an aromatic heterocyclic ring.

[0023] Examples of the aromatic hydrocarbon ring include six-membered aromatic hydrocarbon rings such as a benzene ring, a phenalene ring, and a phenanthrene ring, and fused rings in which two or more of the six-membered aromatic hydrocarbon rings are fused together.

[0024] Examples of the aromatic heterocycle include 6-membered aromatic heterocycles containing a nitrogen atom as a heteroatom, such as a pyridine ring, a pyrimidine ring, and a 1,3,5-triazine ring.

[0025] Ar １ , Ar ２ As the aromatic ring in the above formula, a six-membered aromatic ring is preferred, and a benzene ring or a 1,3,5-triazine ring is particularly preferred, in that a metal complex crystal having a three-dimensional network structure with large pores can be obtained.

[0026] R １ , R ２Examples of the divalent hydrocarbon group in the formula (I) include linear or branched alkylene groups having 1 to 18 carbon atoms, such as methylene, methylmethylene, dimethylmethylene, ethylene, propylene, and trimethylene; 1,2-cyclopentylene, 1,3-cyclopentylene, cyclopentylidene, 1,2-cyclohexylene, 1,3-cyclohexylene, 1,4-cyclohexylene, and cyclohexylidene; C cycloalkylene groups such as phenylene groups (e.g., o-phenylene groups, m-phenylene groups, p-phenylene groups), phenylenebis(methylene) groups (e.g., 1,2-phenylenebis(methylene) groups, 1,3-phenylenebis(methylene) groups, 1,4-phenylenebis(methylene) groups), biphenylene groups, naphthylene groups, binaphthylene groups, anthracenylene groups, and phenanthrylene groups; ６－１４ Examples include an arylene group.

[0027] R １ , R ２ The divalent heterocyclic group in the formula (I) is a group obtained by removing two hydrogen atoms from the structural formula of a heterocycle. The heterocycle includes aromatic heterocycles and non-aromatic heterocycles. Examples of such heterocycles include 3- to 20-membered rings (preferably 3- to 10-membered rings, particularly preferably 4- to 6-membered rings) containing carbon atoms and at least one heteroatom (e.g., oxygen atom, sulfur atom, nitrogen atom, etc.) as ring-constituting atoms, and fused rings thereof. Specifically, heterocycles containing an oxygen atom as a heteroatom (for example, three-membered rings such as an oxirane ring; four-membered rings such as an oxetane ring; five-membered rings such as a furan ring, a tetrahydrofuran ring, an oxazole ring, an isoxazole ring, and a γ-butyrolactone ring; six-membered rings such as a 4-oxo-4H-pyran ring, a tetrahydropyran ring, and a morpholine ring; fused rings such as a benzofuran ring, an isobenzofuran ring, a 4-oxo-4H-chromene ring, a chroman ring, and an isochroman ring; 3-oxatricyclo[4.3.1.1 ４，８ ] undecan-2-one ring, 3-oxatricyclo[4.2.1.0 ４，８]nonan-2-one ring and the like), heterocycles containing a sulfur atom as a heteroatom (for example, 5-membered rings such as a thiophene ring, a thiazole ring, an isothiazole ring, a thiadiazole ring, and the like; 6-membered rings such as a 4-oxo-4H-thiopyran ring, and the like; fused rings such as a benzothiophene ring), heterocycles containing a nitrogen atom as a heteroatom (for example, 5-membered rings such as a pyrrole ring, a pyrrolidine ring, a pyrazole ring, an imidazole ring, and a triazole ring; 6-membered rings such as an isocyanuric ring, a pyridine ring, a pyridazine ring, a pyrimidine ring, a pyrazine ring, a piperidine ring, and the like; indole ring, indoline ring, quinoline ring, acridine ring, a naphthyridine ring, a quinazoline ring, and a fused ring such as a purine ring), and the like.

[0028] L １ , L ２ are the same or different and represent a single bond or a linking group. The linking group is a divalent group having one or more atoms, such as a divalent hydrocarbon group.

[0029] Examples of the divalent hydrocarbon group include linear or branched alkylene groups having 1 to 18 carbon atoms, such as methylene, methylmethylene, dimethylmethylene, ethylene, propylene, and trimethylene; cycloalkylene groups having 3 to 18 carbon atoms, such as 1,2-cyclopentylene, 1,3-cyclopentylene, cyclopentylidene, 1,2-cyclohexylene, 1,3-cyclohexylene, 1,4-cyclohexylene, and cyclohexylidene; C alkylene groups such as phenylene groups (e.g., o-phenylene, m-phenylene, and p-phenylene), naphthylene groups (e.g., 1,3-naphthylene, 1,4-naphthylene, 1,5-naphthylene, and 2,7-naphthylene), anthracenylene, and phenanthrylene groups. ６－１４ arylene groups; and groups in which two or more of these are linked together [for example, phenylenebis(methylene) groups (for example, 1,2-phenylenebis(methylene) groups, 1,3-phenylenebis(methylene) groups, 1,4-phenylenebis(methylene) groups), biphenylene groups, binaphthylene groups].

[0030] The divalent hydrocarbon group includes C ６－１４ an arylene group, or two or more of the arylene groups are each a single bond or C １－５Groups linked via an alkylene group are preferred, with a phenylene group or naphthylene group being particularly preferred, and a phenylene group being most preferred.

[0031] The benzene ring and pyridine ring in the formulae (c1), (c2), (p1), (p2) and (p3) may have a substituent other than the groups shown in the formulae.

[0032] Examples of the substituent include a halogen atom, an oxo group, a hydroxyl group, a substituted oxy group (e.g., C １－４ alkoxy group), cyano group, nitro group, substituted or unsubstituted amino group (e.g., mono- or di-C such as methylamino group, dimethylamino group, ethylamino group, diethylamino group, etc. １－４ alkylamino groups; 5- to 8-membered cyclic amino groups such as 1-pyrrolidinyl, piperidino, and morpholino groups; C groups such as acetylamino, propionylamino, and benzoylamino groups; １－１０ acylamino group; sulfonylamino group such as benzenesulfonylamino group, p-toluenesulfonylamino group, etc.), sulfonic acid group, alkyl group (for example, C groups such as methyl group, ethyl group, etc. １－４ alkyl groups), alkenyl groups (for example, vinyl groups, allyl groups, 1-butenyl groups, etc.) ２－４ alkenyl group), alkynyl group (e.g., ethynyl group, propynyl group, etc. ２－４ alkynyl group), C ３－８ cycloalkyl groups, aryl groups (e.g., C groups such as phenyl groups and naphthyl groups) ６－１０ aryl groups) and the like.

[0033] When the benzene ring or pyridine ring in the formulae (c1), (c2), (p1), (p2), and (p3) has two or more substituents, two groups selected from the substituents may be bonded to each other to form a ring.

[0034] Furthermore, the benzene ring or pyridine ring in the formulae (c1), (c2), (p1), (p2) and (p3) may be condensed with an aromatic or non-aromatic hydrocarbon ring or heterocycle.

[0035] Specific examples of the compound represented by formula (c1) include compounds represented by the following formulae (c1-1) to (c1-4). The compounds represented by the following formulae include compounds in which a CONH group (or CONH-L- group) is bonded at the ortho-position, meta-position, or para-position relative to the bonding position of the carboxyl group on the benzene ring. In the following formulae, L １１ ~L １３ Each of C independently represents a linking group. The linking group is preferably a divalent hydrocarbon group, and C ６－１４ an arylene group, or two or more of the arylene groups are each a single bond or C １－５ A group bonded via an alkylene group is more preferred, a phenylene group or a naphthylene group is particularly preferred, and a phenylene group is most preferred.

[0036] As the compound represented by formula (c1), the compound represented by formula (c1-1) and the compound represented by formula (c1-2) are preferred, in that a three-dimensional network-structure metal complex crystal having large pores can be obtained.

[0037] As the compound represented by the formula (c1), the compound represented by the formula (c1-1) and the compound represented by the formula (c1-3) are preferred in that they give a three-dimensional network-structure metal complex crystal having large pores.

[0038] Specific examples of the compound represented by formula (c2) include compounds represented by the following formulae (c2-1) to (c2-5). The compound represented by formula (c2-1) below includes a compound in which a carboxyl group is bonded at the ortho-, meta-, or para-position relative to the connecting portion of the benzene ring. The same applies to the compounds represented by formulae (c2-2) to (c2-5) below.

[0039] In the formula (c2-2), L ３ represents a linking group. Examples of the linking group include a carbonyl group (-CO-), an ether bond (-O-), a thioether bond (-S-), an ester bond (-COO-), an amide group (-CONH-), an imino group (-NH-), a sulfonyl group (-S(=O) ２ -) etc.

[0040] As the compound represented by the formula (c2), the compound represented by the formula (c2-1) and the compound represented by the formula (c2-2) are preferred in that a three-dimensional network-structure metal complex crystal having large pores can be obtained.

[0041] Specific examples of the compound represented by formula (p1) include compounds represented by the following formulas (p1-1) to (p1-7); compounds corresponding to the compounds represented by the following formulas (p1-1) to (p1-7), in which R in formula (p1) is substituted for the nitrogen atoms of the pyridine rings present at both ends. ２ and compounds in which a group corresponding to the group is bonded at the ortho- or meta-position.

[0042] As the compound represented by formula (p1), the compounds represented by formula (p1-1), formula (p1-2), formula (p1-5), and formula (p1-6) are preferred, the compounds represented by formula (p1-1) and formula (p1-2) are particularly preferred, and the compound represented by formula (p1-2) is most preferred, in that a three-dimensional network-structure metal complex crystal having large pores can be obtained.

[0043] The compound represented by the formula (p2) includes a compound in which the CONH group is bonded to the ortho-, meta-, or para-position relative to the nitrogen atom of the pyridine ring.

[0044] Specific examples of the compound represented by formula (p3) include compounds represented by the following formulae (p3-1) to (p3-4). The compounds represented by the following formulae include compounds in which the CONH group (or CONH-L- group) is bonded to the ortho-, meta-, or para-position relative to the nitrogen atom of the pyridine ring. In the following formulae, L ２１ ~L ２３ Each of C independently represents a linking group. The linking group is preferably a divalent hydrocarbon group, and C ６－１４ an arylene group, or two or more of the arylene groups are each a single bond or C １－５ A group bonded via an alkylene group is more preferred, a phenylene group or a naphthylene group is particularly preferred, and a phenylene group is most preferred.

[0045] As the compound represented by the formula (p3), the compound represented by the formula (p3-1) and the compound represented by the formula (p3-2) are preferred in that they give a three-dimensional network-structure metal complex crystal having large pores.

[0046] As the compound represented by the formula (p3), the compound represented by the formula (p3-1) and the compound represented by the formula (p3-3) are preferred in that they give a three-dimensional network-structure metal complex crystal having large pores.

[0047] The ligands constituting the metal complex crystal include a carboxylic acid ligand (c) and a pyridine ligand (p), and the content ratio of the carboxylic acid ligand (c) to the pyridine ligand (p) [carboxylic acid ligand (c) / pyridine ligand (p); molar ratio] is, for example, 30 / 70 to 70 / 30, preferably 40 / 60 to 60 / 40, particularly preferably 45 / 55 to 55 / 45, in that a three-dimensional network-structure metal complex crystal having large pores can be obtained.

[0048] When the ligand contains a compound represented by the formula (c1) and a compound represented by the formula (p1), the content ratio thereof [compound represented by the formula (c1) / compound represented by the formula (p1)] is, for example, 30 / 70 to 70 / 30, preferably 40 / 60 to 60 / 40, and particularly preferably 45 / 55 to 55 / 45.

[0049] When the ligand contains a compound represented by the formula (c1) above and a compound represented by the formula (p2) above, the content ratio thereof [compound represented by the formula (c1) above / compound represented by the formula (p2) above; molar ratio] is, for example, 30 / 70 to 70 / 30, preferably 40 / 60 to 60 / 40, and particularly preferably 45 / 55 to 55 / 45.

[0050] When the ligand contains a compound represented by the formula (c2) and a compound represented by the formula (p2), the content ratio thereof [compound represented by the formula (c2) / compound represented by the formula (p2)] is, for example, 30 / 70 to 70 / 30, preferably 40 / 60 to 60 / 40, and particularly preferably 45 / 55 to 55 / 45.

[0051] When the ligand contains a compound represented by the formula (c2) and a compound represented by the formula (p3), the content ratio thereof [compound represented by the formula (c2) / compound represented by the formula (p3)] is, for example, 30 / 70 to 70 / 30, preferably 40 / 60 to 60 / 40, and particularly preferably 45 / 55 to 55 / 45.

[0052] The content ratio of the metal ion to the carboxylic acid ligand (c) in the metal complex crystal [metal ion / carboxylic acid ligand (c); molar ratio] is, for example, 30 / 70 to 70 / 30, preferably 40 / 60 to 60 / 40, and particularly preferably 45 / 55 to 55 / 45.

[0053] The content ratio of the metal ion to the pyridine-based ligand (p) in the metal complex crystal [metal ion / pyridine-based ligand (p); molar ratio] is, for example, 20 / 80 to 80 / 20, preferably 25 / 75 to 60 / 40, particularly preferably 30 / 70 to 45 / 55, and most preferably 30 / 70 to 40 / 60.

[0054] The ligand may contain other ligands in addition to the carboxylic acid-based ligand (c) and the pyridine-based ligand (p). Examples of the other ligands include F － , Cl － ,Br － , I － , SCN － , NO ３ － , ClO ４ － , B.F. ４ － , SbF ４ － , P.F. ６ － , AsF ６ － , C.H. ３ COO － Examples of anions include:

[0055] As the anion, NO is preferred because it can produce a three-dimensional network structure metal complex crystal having large pores. ３ － , F － , Cl － ,Br － , and I－ Preferred are anions selected from NO ３ － is particularly preferred.

[0056] The proportion of the total content of the carboxylic acid-based ligand (c) and the pyridine-based ligand (p) in the total amount of ligands constituting the metal complex crystal is, for example, 50% by weight or more, preferably 60% by weight or more, more preferably 70% by weight or more, even more preferably 80% by weight or more, and particularly preferably 90% by weight or more.

[0057] The metal complex crystal has a three-dimensional network structure with regularly arranged pores. The pores are spaces present inside the metal complex crystal and are partitioned by a network structure composed of metal ions and ligands.

[0058] The pores are preferably arranged three-dimensionally and regularly without disorder to the extent that they can be confirmed by X-ray structural analysis.

[0059] The shape of the pores is not particularly limited, but it is preferable that each pore has a uniform shape and size to the extent that it can be confirmed by X-ray structural analysis.

[0060] The size of the pores present in one unit cell is preferably large enough to encapsulate one to several (for example, 1 to 6) organic compounds (X).

[0061] The size of the vacancy correlates with the diameter of the inscribed circle of the vacancy (hereinafter sometimes simply referred to as the "inscribed circle of the vacancy") in a plane parallel to the crystal plane that is closest to perpendicular to the direction in which the vacancy extends (hereinafter sometimes referred to as the "parallel plane"). The larger the inscribed circle, the larger the vacancy, and the smaller the inscribed circle, the smaller the vacancy.

[0062] The "direction in which the vacancy extends" can be determined by the following method. First, a crystal plane 1 (one of six crystal planes connecting four lattice points contained in one unit cell) is selected in an appropriate direction that intersects the target vacancy. Then, atoms that constitute the metal complex crystal and are present on crystal plane 1 are represented using van der Waals radii, and a cross-sectional view of the vacancy is drawn, with crystal plane 1 as the cutting plane. Similarly, a cross-sectional view of the vacancy is drawn, with crystal plane 2, which is shifted by one unit cell from crystal plane 1, as the cutting plane. Next, a straight line is drawn in the three-dimensional diagram to connect the centers of the cross-sectional shapes of the vacancies on each crystal plane. The direction of the line obtained at this time is the direction in which the vacancy extends.

[0063] The "diameter of the inscribed circle of the hole" can be determined by the following method. First, a cross-sectional view of the hole is drawn using the method described above. Next, an inscribed circle is drawn on the cross-sectional view, the diameter of the inscribed circle is measured, and the obtained measurement value is converted to an actual scale, thereby determining the actual diameter of the inscribed circle of the hole. Furthermore, by gradually translating the parallel planes within one unit cell, cross-sectional views of the hole on each parallel plane are drawn, and the diameter of the inscribed circle is measured, thereby determining the diameter of the inscribed circle at the narrowest part and the diameter of the inscribed circle at the widest part.

[0064] The diameter of the inscribed circle of the pore is, for example, 8 to 12 Å, preferably 9 to 12 Å.

[0065] Furthermore, when the shape of the pores is significantly different from a perfect circle, it is preferable to predict the size of the pores from the minor axis and major axis of the inscribed ellipse of the pores in the parallel plane.

[0066] The major axis of the inscribed ellipse of the pore is preferably 10 to 15 Å, more preferably 10 to 12 Å, and the minor axis of the inscribed ellipse of the pore is preferably 8 to 15 Å, more preferably 9 to 11 Å.

[0067] The metal complex crystal contains a ligand having an amide group (CONH) as a constituent element, and the amide group (CONH group) and the CO group and NH group that constitute the amide group can interact with various functional groups via hydrogen bonds. Therefore, the metal complex crystal can determine the molecular structure of a wide range of organic compounds, or a large number of organic compounds. Furthermore, the metal complex crystal can firmly fix organic compounds within the pores through hydrogen bonds with the amide group, CO group, or NH group. Therefore, by using the metal complex crystal, it is possible to determine with a high probability the molecular structures of various organic compounds that have functional groups that interact with amide groups, CO groups, or NH groups.

[0068] Therefore, the metal complex crystal can be suitably used as a material for forming a sample for X-ray structural analysis of the organic compound in the crystalline sponge method (so-called crystalline sponge), or as a metal complex crystal for molecular structural analysis of organic compounds (i.e., a metal complex crystal used to analyze the molecular structure of an organic compound by X-ray structural analysis).

[0069] [Method for Producing Metal Complex Crystal] The metal complex crystal can be produced, for example, by reacting a carboxylic acid-based ligand (c), a pyridine-based ligand (p), and a salt of a metal ion and a counter ion (hereinafter, sometimes referred to as a "metal salt") in the presence of a solvent.

[0070] Examples of the counter ion include F － , Cl － ,Br － , I － , SCN － , NO ３ － , ClO ４ － , B.F. ４ － , SbF ４ － , P.F. ６ － , AsF ６ － , C.H. ３ COO － Examples of anions include:

[0071] The molar ratio of the carboxylic acid ligand (c) to the pyridine ligand (p) is, for example, 10 / 90 to 90 / 10. The lower limit of the ratio is preferably 15 / 85, particularly preferably 20 / 80, in order to obtain a three-dimensional network-structured metal complex crystal having large pores. The upper limit of the ratio is preferably 80 / 20, particularly preferably 60 / 40, most preferably 55 / 45, and particularly preferably 45 / 55, in order to obtain a three-dimensional network-structured metal complex crystal having large pores.

[0072] The amount of the metal salt used is, for example, 0.5 to 3.5 moles, preferably 0.5 to 2.0 moles, and particularly preferably 0.8 to 1.5 moles, per mole of the carboxylic acid ligand (c).

[0073] The amount of the metal salt used is, for example, 0.2 to 3.5 moles, preferably 0.3 to 2.0 moles, and particularly preferably 0.4 to 1.0 moles, per mole of the pyridine-based ligand (p).

[0074] Examples of the solvent include water; benzene; toluene, xylene, ethylbenzene, trifluoromethylbenzene (or trifluorotoluene), chlorobenzene, anisole, benzonitrile, nitrobenzene, ethyl benzoate, and other benzene derivatives in which at least one hydrogen atom bonded to the benzene ring is substituted with a halogen atom, an alkyl group, a haloalkyl group, an alkoxy group, a cyano group, a nitro group, a substituted oxycarbonyl group, or the like; aliphatic hydrocarbons such as hexane, heptane, and octane; alicyclic hydrocarbons such as cyclohexane; haloalkanes such as carbon tetrachloride, chloroform, dichloromethane, and 1,2-dichloroethane; ketones such as acetone and methyl ethyl ketone; esters such as methyl acetate, ethyl acetate, isopropyl acetate, and butyl acetate; amides such as N,N-dimethylformamide, N,N-dimethylacetamide (DMA), and N-methylpyrrolidone; nitriles such as acetonitrile and propionitrile; chain or cyclic ethers such as diethyl ether, dibutyl ether, dimethoxyethane, dioxane, and tetrahydrofuran; and organic acids such as acetic acid. These may be used alone or in combination of two or more.

[0075] Among these, a mixture of water and an amide (particularly DMA) is preferred as the solvent. The volume ratio of water to the total volume of water and the amide is, for example, 5 to 95 vol%. In terms of obtaining a three-dimensional network-structured metal complex crystal having large pores, the lower limit of the volume ratio is preferably 10 vol%, particularly preferably 15 vol%, and the upper limit of the volume ratio is preferably 80 vol%, particularly preferably 60 vol%, more preferably 50 vol%, even more preferably 40 vol%, particularly preferably 30 vol%, most preferably 25 vol%, and particularly preferably 17 vol%.

[0076] The reaction temperature is, for example, 60 to 100°C, preferably 70 to 90°C, and particularly preferably 80 to 90°C.

[0077] The reaction time is, for example, 1 to 10 days, preferably 3 to 10 days, and particularly preferably 5 to 8 days.

[0078] The reaction atmosphere is not particularly limited as long as it does not inhibit the reaction, and may be, for example, an air atmosphere, a nitrogen atmosphere, an argon atmosphere, or the like.

[0079] After the reaction is completed, the resulting reaction product may be separated and purified by common methods such as precipitation, washing and filtration.

[0080] [Method for determining the molecular structure of organic compound (X)] The method for determining the molecular structure of organic compound (X) includes the following steps 1 and 2. Step 1: The organic compound (X) is impregnated into the metal complex crystal to fix the organic compound (X) in the pores of the metal complex crystal. Step 2: The metal complex crystal to which the organic compound (X) is fixed is irradiated with X-rays, and the obtained diffraction data is analyzed to determine the molecular structure of the organic compound (X).

[0081] The organic compound (X) is, for example, a compound having at least one functional group that interacts with the amide group (CONH group) or the CO group or NH group constituting the amide group via a hydrogen bond, which is contained in the metal complex crystal.

[0082] Examples of the functional group that interacts with at least one group selected from the group consisting of a CONH group, a CO group, and an NH group include groups having an electronegativity of 1.0 to 4.0 (preferably 1.6 to 3.6, particularly preferably 2.0 to 3.4).

[0083] Examples of the functional group include a substituted or unsubstituted amino group, a carboxyl group, an active methylene group, a nitrile group, a ketone group, an aldehyde group, an ester group, an ether group, an amide group, a hydroxy group, a halogen group, and a sulfonamide group.

[0084] The molecular weight of the organic compound (X) is, for example, 1,000 or less, preferably 800 or less, and particularly preferably 600 or less. The lower limit of the molecular weight of the organic compound (X) is, for example, 15, preferably 30, and particularly preferably 50.

[0085] The organic compound (X) is preferably a hydrophilic compound, and the log P value (octanol / water partition coefficient) of the organic compound (X) is, for example, from −5 to 7. In terms of improving the determination rate of the molecular structure, the lower limit of the log P is preferably −3, particularly preferably −1, and the upper limit of the log P is preferably 6, particularly preferably 5, most preferably 4.5, and particularly preferably 3. The log P value of the organic compound (X) can be determined using commercially available software (for example, the software "EPI suite" jointly developed by the U.S. EPA (The Estimations Programs Interface for Windows) and Syracuse).

[0086] The organic compound (X) is preferably a compound having no phenolic hydroxyl group.

[0087] (Step 1) Step 1 is a step of impregnating the metal complex crystal with the organic compound (X) to fix the organic compound (X) in the pores of the metal complex crystal.

[0088] As the metal complex crystal, it is preferable to select and use one that has excellent transparency and a clear external shape (e.g., needle-like, block-like, flaky, etc.) from among the metal complex crystals obtained by the above-mentioned method for producing a metal complex crystal, in order to improve the determination rate of the molecular structure.

[0089] When the metal complex crystal is a needle-like or block-like particle, the length of the metal complex crystal is, for example, 10 μm or more, preferably 10 to 200 μm, and particularly preferably 10 to 100 μm. If the metal complex crystal is too small, the measurement time tends to be long, whereas if the metal complex crystal is too large, it becomes difficult to sufficiently penetrate the organic compound (X), and the determination rate of the molecular structure tends to be low.

[0090] The amount of the metal complex crystal used is, for example, 0.1 to 50 mg, preferably 0.5 to 15 mg, and particularly preferably 1 to 3 mg.

[0091] The method of infiltrating the organic compound (X) into the metal complex crystal and fixing the organic compound (X) in the pores of the metal complex crystal is preferably adjusted appropriately depending on the state (liquid or solid) of the organic compound (X).

[0092] When the organic compound (X) is a liquid, the immobilization method may include placing the metal complex crystal in a container such as a test tube, adding the organic compound (X) thereto, and allowing the mixture to stand at −20 to 100° C. for 0.25 to 24 hours.

[0093] When the organic compound (X) is liquid, it may be subjected to a separation treatment such as liquid chromatography in advance to increase the purity, and then added to a container such as a test tube.

[0094] When the organic compound (X) is a solid, the immobilization method may include placing the metal complex crystal in a container such as a test tube, adding a solution of the organic compound (X) dissolved in a solvent inert to the organic compound (X) (hereinafter, sometimes referred to as an "inert solvent"), and allowing the solution to stand at -20 to 100°C for 0.25 to 24 hours. After the standing, the metal complex crystal impregnated with the organic compound (X) may be subjected to a treatment such as drying to concentrate the solution that has impregnated the metal complex crystal. By performing the concentration treatment, the immobilization rate of the organic compound (X) in the pores is increased, and the determination rate of the molecular structure is improved.

[0095] The metal complex crystal has excellent solvent resistance and can maintain its crystalline structure in various solvents. Therefore, a solvent that improves the determination rate of the molecular structure can be selected from among inert solvents and used. Examples of the inert solvent include alcohols such as methanol, ethanol, and isopropyl alcohol; and chain or cyclic ethers such as tetrahydrofuran (THF), dimethoxyethane, and dioxane. These can be used alone or in combination of two or more.

[0096] When the organic compound (X) is a solid, the concentration of the organic compound (X) in a solution obtained by dissolving the organic compound (X) in an inert solvent is, for example, 0.001 to 50 μg / μL, preferably 0.01 to 5 μg / μL, and more preferably 0.1 to 1 μg / μL.

[0097] Since the metal complex crystal has an amide group, when the organic compound (X) is impregnated into the metal complex crystal, the organic compound (X) incorporated into the pores of the metal complex crystal can be firmly fixed by hydrogen bonds.

[0098] Through this step, a sample for X-ray structural analysis is obtained in which the organic compound (X) is fixed in the pores of the metal complex crystal.

[0099] (Step 2) Step 2 is a step of irradiating the X-ray structural analysis sample obtained in the previous step (i.e., the sample in which the organic compound (X) is fixed in the pores of the metal complex crystal) with X-rays, and analyzing the obtained diffraction data to determine the molecular structure of the organic compound (X).

[0100] In the method for determining the molecular structure of organic compound (X), there is no need to go through a process of crystallizing organic compound (X). Therefore, even if the amount of organic compound (X) is too small to obtain a single crystal, or even if organic compound (X) is a compound that cannot be crystallized into a single crystal, the molecular structure can be determined by X-ray structural analysis.

[0101] The method for determining the molecular structure of organic compound (X) can be suitably used to determine the molecular structures of trace impurities in pharmaceuticals, food additives, trace components in plants and animals, etc.

[0102] The above-described configurations and combinations thereof of the present disclosure are merely examples, and additions, omissions, substitutions, and modifications of the configurations are possible as appropriate without departing from the spirit of the present disclosure. Furthermore, each aspect disclosed in this specification can be combined with any other feature disclosed in this specification. Furthermore, the present disclosure is not limited by the embodiments.

[0103] The present disclosure will be explained in more detail below using examples, but the present disclosure is not limited to these examples.

[0104] The single crystal X-ray structure analysis was carried out using the following automatic single crystal X-ray diffractometer: Automatic single crystal X-ray diffractometer: "XtaLABSynergy Custom" manufactured by Rigaku Corporation; Radiation source: Cu-Kα ray (wavelength 0.79 Å); Output: 50 mA, 24 kV

[0105] Example 1 (Production of Metal Complex Crystal 1) In a 10 mL test tube, a carboxylic acid-based ligand (18 mg, 0.1 mol) represented by the following formula (c1-1-1), a pyridine-based ligand (59 mg, 0.2 mol) represented by the following formula (p1-2), and Zn(NO ３ ) ２ 6H ２ O (62 mg, 0.1 mol) and DMA / H ２ A mixed solvent (6 mL / 2 mL) of DMA was added to the test tube and sonicated to dissolve the DMA. The test tube was then tightly capped and allowed to stand at 85°C for 6 days. The crystals deposited on the test tube wall were crushed to a size of approximately 100-200 μm by ultrasonication. The solvent in the test tube was removed with a Pasteur pipette, and 3 mL of DMA was added. This procedure was repeated three times. This yielded needle-like or block-like single-crystal particles of metal complex crystal 1, which contained DMA within their pores. The crystal structure of the resulting metal complex crystal 1 was confirmed by single-crystal X-ray structural analysis. A schematic diagram of metal complex crystal 1 is shown in Figure 1.

[0106]

[0107] Single crystal X-ray structural analysis showed that the crystal structure of metal complex crystal 1 comprises an infinite network having repeating units each consisting of one molecule of the carboxylic acid-based ligand represented by the above formula (c1-1-1), two molecules of the pyridine-based ligand represented by the above formula (p1-2), and three zinc ions.

[0108] Example 2 (Production of Metal Complex Crystal 2) Single crystal particles of Metal Complex Crystal 2 were obtained in the same manner as in Example 1, except that a carboxylic acid ligand represented by the following formula (c2-1-1) was used instead of the carboxylic acid ligand represented by the above formula (c1-1-1), and a pyridine ligand represented by the following formula (p3-1) was used instead of the pyridine ligand represented by the above formula (p1-2).

[0109]

[0110] Comparative Example 1 (Production of Metal Complex Crystal 3) In a 50 mL vial, 2,4,6-tris(4-pyridyl)-1,3,5-triazine (TPT) (31.3 mg, 0.1 mmol), CHCl ３ 21 mL of zinc chloride and 1.7 mL of methanol were added and sonicated to completely dissolve them. 4.5 mL of the resulting solution was placed in a screw-cap test tube. Next, zinc chloride (20.5 mg, 0.15 mmol) and 5 mL of methanol were added to a 10 mL vial and sonicated to dissolve them. 1 mL of the resulting solution was added to the screw-cap test tube. The screw-cap test tube was then capped and allowed to stand at room temperature for 3 days. This yielded single-crystal particles of metal complex crystal 3.

[0111] Single crystal X-ray structural analysis was carried out on the obtained metal complex crystal 3. A schematic diagram of the metal complex crystal 3 is shown in FIG.

[0112] Evaluation of Solvent Resistance The solvent resistance of the metal complex crystal 1 obtained in Example 1 and the metal complex crystal 3 obtained in Comparative Example 1 was evaluated by the following method. That is, one single crystal particle of the metal complex crystal was placed in a microvial, 1 μL of the following solvent was added thereto, and the mixture was allowed to stand at 50° C. or room temperature (25° C.) for 17 hours. After standing, it was visually observed whether the crystal structure was maintained. Then, the solvent resistance was evaluated according to the following criteria. <Evaluation criteria for solvent resistance> Excellent (○): The crystal structure was maintained, and the skeleton of the metal complex crystal could be observed by single crystal X-ray measurement. Good (Δ): The crystal structure was not maintained when left standing at 50° C. for 17 hours, but the crystal structure was maintained when left standing at room temperature for 17 hours. Poor (×): The crystal structure was not maintained.

[0113]

[0114] Example 11 (Structure determination of organic compound having a ketone group) 45 μL of THF was added to a microvial equipped with a septum cap, and then one single crystal particle of the metal complex crystal 1 obtained in Example 1 was immersed therein. Thereafter, as much THF as possible was removed using a pipette.

[0115] Next, 1 μg of 4-methylacetophenone was added to the microvial. Thereafter, the microvial was capped and allowed to stand in a constant temperature room at 50°C for 17 hours. Thereafter, metal complex crystal 1 was removed from the microvial. The metal complex crystal 1 removed from the microvial was used as a sample for X-ray structural analysis.

[0116] The obtained X-ray structure analysis sample was mounted on an X-ray structure analyzer, and crystal structure analysis was performed. The crystal structure analysis ability was evaluated according to the following evaluation criteria. The results are shown in the table below. <Evaluation criteria for crystal structure analysis ability> ◎ (Excellent): The molecular structure could be determined very clearly. ○ (Good): The molecular structure could be determined with a certain degree of accuracy. × (Unacceptable): The molecular structure could not be determined.

[0117] Furthermore, the crystal structure analysis results confirmed that a total of three hydrogen atoms, one hydrogen atom of the amide group and two hydrogen atoms bonded to the benzene ring of Metal Complex Crystal 1, were hydrogen-bonded to the carbonyl oxygen of 4-methylacetophenone (i.e., oxygen atoms constituting the carbonyl). A schematic diagram of the crystal structure of the X-ray structure analysis sample is shown in Figure 3.

[0118] Examples 12 and 13 (Structure determination of organic compounds having a ketone group) The same procedures as in Example 11 were carried out except that 1,3-diphenyl-2-propanone or 5-nonanone was used instead of 4-methylacetophenone. The results are shown in the table below.

[0119] Comparative Examples 11 to 13 (Structure determination of organic compound having ketone group) The same procedures as in Examples 11 to 13 were carried out except that Metal Complex Crystal 3 was used instead of Metal Complex Crystal 1. The results are shown in the table below.

[0120]

[0121] Example 14 (Structure Determination of Organic Compound Having Amide Group) An X-ray structural analysis sample was obtained in the same manner as in Example 11, except that 1,3-dimethyl-2-imidazolidinone was used instead of 4-methylacetophenone. The obtained X-ray structural analysis sample was mounted on an X-ray structural analysis apparatus and subjected to crystal structure analysis. It was confirmed that a total of three hydrogen atoms, one hydrogen atom of the amide group of Metal Complex Crystal 1 and two hydrogen atoms bonded to the benzene ring, were hydrogen-bonded to the carbonyl oxygen of 1,3-dimethyl-2-imidazolidinone. A schematic diagram of the crystal structure of the X-ray structural analysis sample is shown in FIG. 4.

[0122] Example 15 (Structure determination of organic compound having amide group) The procedure of Example 14 was repeated except that N,N-dimethylacetamide was used instead of 1,3-dimethyl-2-imidazolidinone. The results are shown in the table below.

[0123] Comparative Examples 14 and 15 (Structure determination of organic compound having an amide group) The same procedures as in Examples 14 and 15 were carried out except that Metal Complex Crystal 3 was used instead of Metal Complex Crystal 1. The results are shown in the table below.

[0124] *1 The crystal structure of metal complex crystal 3 collapsed.

[0125] Example 16 (Structure Determination of Organic Compound Having Ester Group) A sample for X-ray structural analysis was obtained in the same manner as in Example 11, except that methyl 2-furancarboxylate (LogP value: 1.00 (database match)) was used instead of 4-methylacetophenone. The obtained sample for X-ray structural analysis was mounted on an X-ray structural analyzer and subjected to crystal structure analysis. It was confirmed that a total of three hydrogen atoms, one hydrogen atom of the amide group and two hydrogen atoms bonded to the benzene ring of Metal Complex Crystal 1, were hydrogen-bonded to the carbonyl oxygen of methyl 2-furancarboxylate, and that the oxygen atom of the furan ring was also hydrogen-bonded to a hydrogen atom bonded to the benzene ring. A schematic diagram of the crystal structure of the sample for X-ray structural analysis is shown in FIG. 5.

[0126] Examples 17 and 18 (Structure Determination of Organic Compound Having Ester Group) The same procedure as in Example 16 was carried out, except that γ-butyrolactone (Log P value: −0.64 (database match)) or phthalide (Log P value: 0.80 (database match)) was used instead of methyl 2-furancarboxylate. As a result, the overall molecular structure of each organic compound could be determined by X-ray diffraction photographs. Furthermore, it was confirmed that the carbonyl oxygen of methyl 2-furancarboxylate interacted with a total of three hydrogen atoms, one hydrogen atom of the amide group of metal complex crystal 1 and two hydrogen atoms bonded to the benzene ring, thereby fixing the compound within the pores of metal complex crystal 1. It was confirmed that the carbonyl oxygen of γ-butyrolactone interacted with a total of three hydrogen atoms, one hydrogen atom of the amide group of metal complex crystal 1 and two hydrogen atoms bonded to the benzene ring, thereby fixing the compound within the pores of metal complex crystal 1.

[0127] Example 19 (Structure Determination of Organic Compound Having a Hydroxy Group, an Ether Group, or an Aldehyde Group) A sample for X-ray structural analysis was obtained in the same manner as in Example 11, except that 2,4-dimethoxybenzyl alcohol (Log P value: 1.24) was used instead of 4-methylacetophenone. The obtained sample for X-ray structural analysis was mounted on an X-ray structural analyzer and subjected to crystal structure analysis. It was confirmed that a total of three hydrogen atoms, one hydrogen atom of the amide group of Metal Complex Crystal 1 and two hydrogen atoms bonded to the benzene ring, were hydrogen-bonded to hydrogen atoms constituting the hydroxy group of 2,4-dimethoxybenzyl alcohol. A schematic diagram of the crystal structure of the sample for X-ray structural analysis is shown in FIG. 6.

[0128] Examples 20 and 21 (Structure Determination of Organic Compound Having a Hydroxy Group, an Ether Group, or an Aldehyde Group) The same procedure as in Example 19 was carried out, except that 2,4-dimethyl-1,3-dioxane (Log P value: 1.02 (estimated value)) or 1-naphthaldehyde (Log P value: 2.89 (estimated value)) was used instead of 2,4-dimethoxybenzyl alcohol. As a result, the overall molecular structure of each organic compound could be determined by X-ray diffraction photographs. Furthermore, it was confirmed that the oxygen atom at the 3-position of 2,4-dimethyl-1,3-dioxane interacted with one hydrogen atom of the amide group of the metal complex crystal 1 and two hydrogen atoms bonded to the benzene ring, totaling three hydrogen atoms, and was thereby fixed within the pores of the metal complex crystal 1. It was confirmed that 1-naphthaldehyde is fixed in the pores of metal complex crystal 1 by the oxygen atom constituting the aldehyde group interacting with a total of three hydrogen atoms: one hydrogen atom of the amide group of metal complex crystal 1 and two hydrogen atoms bonded to the benzene ring.

[0129] Example 22 (Structure determination of organic compound having a carboxyl group) 45 μL of THF was placed in a microvial with a septum cap, and then one single crystal of the metal complex crystal 1 containing DMA obtained in Example 1 was immersed therein.

[0130] 2-Naphthalenecarboxylic acid (LogP value: 3.28 (database match)) was dissolved in THF to a concentration of 1 μg / 1 μL, and 5 μL of the resulting sample solution (containing 5 μg of 2-naphthalenecarboxylic acid) was added to a microvial. Thereafter, the cap of the microvial was closed, a pinhole was opened in the septum with a syringe needle having a needle hole diameter of 0.8 mm, and this was allowed to stand in a thermostatic chamber at 50°C for 17 hours. Thereafter, metal complex crystal 1 was removed from the microvial. Metal complex crystal 1 removed from the microvial was used as a sample for X-ray structural analysis.

[0131] The obtained sample for X-ray structural analysis was mounted on an X-ray structural analyzer and subjected to crystal structure analysis, which confirmed that one hydrogen atom in the amide group of Metal Complex Crystal 1 and two hydrogen atoms bonded to the benzene ring, a total of three hydrogen atoms, were hydrogen-bonded to the carbonyl oxygen of 2-naphthalenecarboxylic acid. A schematic diagram of the crystal structure of the sample for X-ray structural analysis is shown in Figure 7.

[0132] Example 23 (Structure Determination of Organic Compound Having a Sulfonamide Group) A sample for X-ray structural analysis was obtained in the same manner as in Example 22, except that zonisamide (LogP value: 0.36 (database match)) was used instead of 2-naphthalenecarboxylic acid. The obtained sample for X-ray structural analysis was mounted on an X-ray structural analyzer, and crystal structure analysis was performed. It was confirmed that a total of three hydrogen atoms, one hydrogen atom in the amide group of Metal Complex Crystal 1 and two hydrogen atoms bonded to the benzene ring, were hydrogen-bonded to hydrogen atoms present in the sulfone moiety, amine moiety, and α-position of the sulfonamide group of zonisamide. A schematic diagram of the crystal structure of the sample for X-ray structural analysis is shown in FIG. 8.

[0133] Example 24 (Structure Determination of Organic Compound Having an Amino Group) A sample for X-ray structural analysis was obtained in the same manner as in Example 11, except that 2,4,6-trimethylaniline (LogP value: 2.72) was used instead of 4-methylacetophenone. The obtained sample for X-ray structural analysis was mounted on an X-ray structural analyzer and subjected to crystal structure analysis, confirming that the carbonyl oxygen of Metal Complex Crystal 1 was hydrogen-bonded to the N—H group of 2,4,6-trimethylaniline. A schematic diagram of the crystal structure of the sample for X-ray structural analysis is shown in FIG. 9.

[0134] Example 25 (Structure Determination of Bergapten) A sample for X-ray structural analysis was obtained in the same manner as in Example 22, except that bergapten (Log P value: 1.93 (database match)) was used instead of 2-naphthalenecarboxylic acid. The obtained sample for X-ray structural analysis was mounted on an X-ray structural analyzer, and crystal structure analysis was performed, confirming that a total of three hydrogen atoms, one hydrogen atom in the amide group of Metal Complex Crystal 1 and two hydrogen atoms bonded to the benzene ring, were hydrogen-bonded to the oxygen atom in the ester moiety of bergapten, and that two bergapten molecules were in π-π interaction. Schematic diagrams of the crystal structure of the sample for X-ray structural analysis are shown in Figures 10 and 11.

[0135] Example 26 (Structure Determination of 1-Aminopyrene) A sample for X-ray structural analysis was obtained in the same manner as in Example 22, except that 1-aminopyrene (LogP value: 4.31 (database match)) was used instead of 2-naphthalenecarboxylic acid. The obtained sample for X-ray structural analysis was mounted on an X-ray structural analyzer, and crystal structure analysis was performed, confirming that there was a Π-Π interaction between metal complex crystal 1 and 1-aminopyrene. A schematic diagram of the crystal structure of the sample for X-ray structural analysis is shown in FIG. 12.

[0136] Example 27 The same procedure as in Example 11 was carried out, except that 1-fluoronaphthalene (LogP value: 3.37 (database match)) was used instead of 4-methylacetophenone. As a result, all of the organic compounds were immobilized in the pores of the metal complex crystal 1 through π-π interactions with the metal complex crystal 1, and the overall molecular structure could be determined by X-ray diffraction photographs.

[0137] Example 28 The same procedure as in Example 22 was carried out except that 2-triphenylenecarboxaldehyde was used instead of 2-naphthalenecarboxylic acid. As a result, each organic compound was immobilized in the pores of metal complex crystal 1 through π-π interaction with metal complex crystal 1, and the overall molecular structure could be determined by X-ray diffraction photography.

[0138] In summary, the configuration of the present disclosure and its variations are described below. [1] A metal complex crystal composed of metal ions and ligands coordinated to the metal ions, wherein the metal complex crystal has a three-dimensional network structure with regularly aligned pores, the ligands including a carboxylic acid-based ligand (c) and a pyridine-based ligand (p), and the carboxylic acid-based ligand (c) and the pyridine-based ligand (p) are a combination selected from the following [I] to [IV]: [I] A compound represented by formula (c1) and a compound represented by formula (p1); [II] A compound represented by formula (c1) and a compound represented by formula (p2); [III] A compound represented by formula (c2) and a compound represented by formula (p2); [IV] A compound represented by formula (c2) and a compound represented by formula (p3); [2] The metal complex crystal according to [1], wherein the metal ions are selected from zinc ions, iron ions, cobalt ions, nickel ions, copper ions, and silver ions. [3] The metal complex crystal according to [1] or [2], wherein the compound represented by (c1) is at least one compound selected from the compounds represented by formulas (c1-1) to (c1-4). [4] The metal complex crystal according to any one of [1] to [3], wherein the compound represented by (c1) is a compound represented by formula (c1-1) and / or a compound represented by formula (c1-2). [5] The metal complex crystal according to any one of [1] to [4], wherein the compound represented by (c1) is a compound represented by formula (c1-1) and / or a compound represented by formula (c1-3). [6] The metal complex crystal according to any one of [1] to [5], wherein the compound represented by formula (c2) is at least one compound selected from the compounds represented by formulas (c2-1) to (c2-5). [7] The metal complex crystal according to any one of [1] to [5], wherein the compound represented by (c2) is a compound represented by formula (c2-1) and / or a compound represented by formula (c2-2). [8] The metal complex crystal according to any one of [1] to [7], wherein the compound represented by formula (p1) is at least one compound selected from the compounds represented by formulas (p1-1) to (p1-7).[9] The metal complex crystal according to any one of [1] to [7], wherein the compound represented by formula (p1) is at least one compound selected from compounds represented by formula (p1-1), formula (p1-2), formula (p1-5), and formula (p1-6).

[10] The metal complex crystal according to any one of [1] to [7], wherein the compound represented by formula (p1) is a compound represented by formula (p1-2).

[11] The metal complex crystal according to any one of [1] to

[10] , wherein the compound represented by formula (p3) is at least one compound selected from compounds represented by formulas (p3-1) to (p3-4).

[12] The metal complex crystal according to any one of [1] to

[10] , wherein the compound represented by formula (p3) is a compound represented by formula (p3-1) and / or a compound represented by formula (p3-2).

[13] The metal complex crystal according to any one of [1] to

[10] , wherein the compound represented by formula (p3) is a compound represented by formula (p3-1) and / or a compound represented by formula (p3-3).

[14] The metal complex crystal according to any one of [1] to

[13] , wherein the content ratio of the carboxylic acid ligand (c) to the pyridine ligand (p) [carboxylic acid ligand (c) / pyridine ligand (p); molar ratio] is 30 / 70 to 70 / 30.

[15] The metal complex crystal according to any one of [1] to

[14] , wherein the ligands include a compound represented by formula (c1) and a compound represented by formula (p1), and the compound represented by formula (c1) / compound represented by formula (p1) (molar ratio) is 30 / 70 to 70 / 30.

[16] The metal complex crystal according to any one of [1] to

[15] , wherein the ligand comprises a compound represented by formula (c2) and a compound represented by formula (p2), and the molar ratio of the compound represented by formula (c2) / the compound represented by formula (p2) is 30 / 70 to 70 / 30.

[17] The metal complex crystal according to any one of [1] to

[16] , wherein the ligand comprises a compound represented by formula (c2) and a compound represented by formula (p3), and the molar ratio of the compound represented by formula (c2) / the compound represented by formula (p3) is 30 / 70 to 70 / 30.

[18] The metal complex crystal according to any one of [1] to

[17] , wherein the combined content of the carboxylic acid ligand (c) and the pyridine ligand (p) accounts for 50% by weight or more of the total amount of the ligands.

[19] The metal complex crystal according to any one of [1] to

[18] , wherein the content ratio of the metal ion to the carboxylic acid ligand (c) [metal ion / carboxylic acid ligand (c); molar ratio] is 30 / 70 to 70 / 30.

[20] The metal complex crystal according to any one of [1] to

[19] , wherein the content ratio of the metal ion to the pyridine ligand (p) [metal ion / pyridine ligand (p); molar ratio] is 20 / 80 to 80 / 20.

[21] The metal complex crystal according to any one of [1] to

[20] , wherein the metal complex crystal is used for molecular structure analysis of organic compounds.

[22] The metal complex crystal according to

[21] , wherein the organic compound is an organic compound having a functional group that interacts with a CO group, an NH group, or a CONH group.

[23] The metal complex crystal according to

[21] or

[22] , wherein the organic compound has a log P value of -5 or more and 7 or less.

[24] The metal complex crystal according to any one of

[21] to

[23] , wherein the organic compound is an organic compound having at least one functional group selected from a substituted or unsubstituted amino group, a carboxyl group, an active methylene group, a nitrile group, a ketone group, an aldehyde group, an ester group, an ether group, an amide group, a hydroxy group, a halogen group, and a sulfonamide group.

[25] Use of the metal complex crystal according to any one of [1] to

[20] as a material for forming a sample for X-ray structural analysis of an organic compound.

[26] Use of the organic compound according to

[25] as a material for forming a sample for X-ray structural analysis, wherein the organic compound is an organic compound having a functional group that interacts with a CO group, an NH group, or a CONH group.

[27] Use of the organic compound according to

[25] or

[26] as a material for forming a sample for X-ray structural analysis, wherein the organic compound is an organic compound having a log P value of -5 or more and 7 or less.

[28] Use of the organic compound according to any one of

[25] to

[27] as a material for forming a sample for X-ray structural analysis, wherein the organic compound is an organic compound having at least one functional group selected from a substituted or unsubstituted amino group, a carboxyl group, an active methylene group, a nitrile group, a ketone group, an aldehyde group, an ester group, an ether group, an amide group, a hydroxy group, a halogen group, and a sulfonamide group.

[29] A method for determining the molecular structure of an organic compound (X), comprising the following steps 1 and 2: Step 1: impregnating the metal complex crystal according to any one of [1] to

[24] with the organic compound (X) to fix the organic compound (X) in the pores of the metal complex crystal; and Step 2: irradiating the metal complex crystal with the organic compound (X) fixed with X-rays, and analyzing the obtained diffraction data to determine the molecular structure of the organic compound (X).

[0139] The metal complex crystal of the present disclosure is highly versatile as a material for forming a sample for X-ray structural analysis of an organic compound (X) (particularly a hydrophilic organic compound).

Claims

1. A metal complex crystal composed of a metal ion and a ligand coordinated to the metal ion, the metal complex crystal having a three-dimensional network structure with regularly aligned pores, the ligand including a carboxylic acid ligand (c) and a pyridine ligand (p), the carboxylic acid ligand (c) and the pyridine ligand (p) being a combination selected from the following [I] to [IV]: [I] A compound represented by the following formula (c1) and a compound represented by the following formula (p1): [II] A compound represented by the following formula (c1) and a compound represented by the following formula (p2): [III] A compound represented by the following formula (c2) and a compound represented by the following formula (p2): [IV] A compound represented by the following formula (c2) and a compound represented by the following formula (p3): (In the formula, Ar １ , Ar ２ are the same or different and each represents an aromatic ring; R １ , R ２ L may be the same or different and represents a group selected from a single bond, a divalent hydrocarbon group, a divalent heterocyclic group, and a divalent group formed by linking two or more of the above groups. １ , L ２ are the same or different and represent a single bond or a linking group.

2. The metal complex crystal according to claim 1, wherein the metal ion is selected from the group consisting of zinc ions, iron ions, cobalt ions, nickel ions, copper ions, and silver ions.

3. The metal complex crystal according to claim 1 or 2, which is a metal complex crystal for use in analyzing the molecular structure of an organic compound.

4. The metal complex crystal according to claim 3, wherein the organic compound is an organic compound having a functional group having an interaction with a CO group, an NH group, or a CONH group.

5. The metal complex crystal according to claim 3, wherein the organic compound has a log P value of -5 or more and 7 or less.

6. The metal complex crystal described in claim 3, wherein the organic compound is an organic compound having at least one functional group selected from a substituted or unsubstituted amino group, a carboxyl group, an active methylene group, a nitrile group, a ketone group, an aldehyde group, an ester group, an ether group, an amide group, a hydroxyl group, a halogen group, and a sulfonamide group.

7. A method for determining the molecular structure of an organic compound (X), comprising the following steps 1 and 2: Step 1: The organic compound (X) is permeated into the metal complex crystal according to claim 1 or 2, and the organic compound (X) is fixed in the pores of the metal complex crystal. Step 2: The metal complex crystal to which the organic compound (X) is fixed is irradiated with X-rays, and the obtained diffraction data is analyzed to determine the molecular structure of the organic compound (X).

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