JP2013040126A - Metal complex and adsorbing material comprising the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a metal complex that exhibits excellent gas-adsorbing performance.SOLUTION: The metal complex (for example, a zinc complex) comprises, as ligands, a biphenyldicarboxylic acid compound (for example, 4, 4'-biphenyldicarboxylic acid) and a compound represented by general formula (II).

Description

  The present invention relates to a metal complex and an adsorbent comprising the same. More specifically, the present invention relates to a metal complex comprising a specific dicarboxylic acid compound, at least one metal ion, and a specific organic ligand capable of bidentate coordination with the metal ion. The metal complex of the present invention is carbon dioxide, hydrogen, carbon monoxide, oxygen, nitrogen, hydrocarbon having 1 to 4 carbon atoms, rare gas, hydrogen sulfide, ammonia, sulfur oxide, nitrogen oxide, siloxane, water vapor or organic It is preferable as an adsorbent for adsorbing vapor and the like.

  So far, various adsorbents have been developed in fields such as deodorization and exhaust gas treatment. Activated carbon is a representative example, and is widely used in various industries such as air purification, desulfurization, denitration, and removal of harmful substances by utilizing the excellent adsorption performance of activated carbon. In recent years, the demand for nitrogen has increased for semiconductor manufacturing processes, etc., and as a method for producing such nitrogen, a method of producing nitrogen from air by pressure swing adsorption method or temperature swing adsorption method using molecular sieve charcoal is used. Has been. Molecular sieve charcoal is also applied to various gas separation and purification such as hydrogen purification from methanol cracked gas.

  When separating mixed gas by pressure swing adsorption method or temperature swing adsorption method, generally, molecular sieve charcoal or zeolite is used as the separation adsorbent, and separation is performed by the difference in the equilibrium adsorption amount or adsorption rate. . However, when separating the mixed gas based on the difference in the amount of equilibrium adsorption, the conventional adsorbents cannot selectively adsorb only the gas to be removed, so the separation factor becomes small, and the size of the apparatus is inevitable. . In addition, when separating the mixed gas based on the difference in adsorption speed, only the gas to be removed can be adsorbed depending on the type of gas, but it is necessary to perform adsorption and desorption alternately, and in this case, the apparatus still has to be large. I didn't get it.

  On the other hand, polymer metal complexes that cause a dynamic structural change due to an external stimulus have been developed as adsorbents that give better adsorption performance. When this new dynamic structure change polymer metal complex is used as a gas adsorbent, a unique phenomenon is observed in which gas adsorption does not adsorb up to a certain pressure, but gas adsorption starts when a certain pressure is exceeded. Yes. In addition, a phenomenon has been observed in which the adsorption start pressure varies depending on the type of gas.

  When this phenomenon is applied to, for example, an adsorbent in a pressure swing adsorption type gas separation apparatus, very efficient gas separation is possible. In addition, the pressure swing width can be narrowed, contributing to energy saving. Furthermore, since it can contribute to miniaturization of the gas separation device, it is possible to increase cost competitiveness when selling high-purity gas as a product, of course, even when high-purity gas is used inside its own factory Since the cost required for the equipment that requires high purity gas can be reduced, the manufacturing cost of the final product can be reduced.

  However, the present situation is that cost reduction by further downsizing of the apparatus is required, and in order to achieve this, further improvement in adsorption performance and storage performance is required.

  An aromatic dicarboxylic acid compound, at least one divalent metal ion selected from copper, rhodium, chromium, molybdenum, palladium, zinc and tungsten, and an organic ligand capable of bidentate coordination with the metal ion A polymer metal complex is disclosed (see Patent Document 1). However, what is described in the examples is a polymer metal complex composed of fumaric acid, copper ion and pyrazine, a polymer metal complex composed of terephthalic acid, copper ion and pyrazine, and fumaric acid, rhodium ion and pyrazine. No mention is made of the effect of 4,4′-biphenyldicarboxylic acid derivatives and bidentate organic ligands other than pyrazine on gas adsorption behavior.

  An aromatic dicarboxylic acid compound and at least one divalent metal ion selected from copper, rhodium, chromium, molybdenum, palladium, zinc, and tungsten, and an organic configuration having a pKa that is bidentate to the metal ion of 4 or more. A polymer metal complex composed of a ligand is disclosed (see Patent Document 2). However, what is described in the examples is a polymer metal complex composed of 4,4′-biphenyldicarboxylic acid, copper ion and triethylenediamine, and an organic ligand capable of bidentate coordination other than triethylenediamine is used. No mention is made of the effect on the gas adsorption behavior.

  4,4′-biphenyldicarboxylic acid, 2,7-pyrene dicarboxylic acid and 4,5,9,10-tetrahydropyrene-2,7-dicarboxylic acid, metal ions, and organic coordination capable of bidentate coordination with the metal ions A polymer metal complex comprising a ligand has been disclosed (see Patent Document 3). However, what is described in the examples is a polymer metal complex composed of terephthalic acid, copper ion and triethylenediamine, a polymer metal complex composed of 2,6-naphthalenedicarboxylic acid, copper ion and triethylenediamine, and terephthalic acid. Effect of 4,4'-biphenyldicarboxylic acid derivatives and organic ligands capable of bidentate coordination other than triethylenediamine on gas adsorption behavior Is not mentioned at all.

  4,4′-biphenyldicarboxylic acid, 2,7-pyrene dicarboxylic acid and 4,5,9,10-tetrahydropyrene-2,7-dicarboxylic acid, metal ions, and organic coordination capable of bidentate coordination with the metal ions A polymer metal complex comprising a ligand has been disclosed (see Patent Document 4). However, what is described in the examples is a polymer metal complex composed of 4,4′-biphenyldicarboxylic acid, copper ion and triethylenediamine, and an organic ligand capable of bidentate coordination other than triethylenediamine is used. No mention is made of the effect on the gas adsorption behavior.

  A gas occlusion characterized by comprising a coordination bond between a metal ion, a dicarboxylic acid compound, and an aromatic heterocyclic compound containing a nitrogen atom capable of coordinating two or more metal ions, and having a pore structure A porous organometallic complex is disclosed (see Patent Document 5). However, what is described in the examples is a porous organometallic complex composed of terephthalic acid, a copper ion, and 1,4-di (4-pyridyl) benzene, and a 4,4′-biphenyldicarboxylic acid derivative, No mention is made of the effect of organic ligands other than 1,4-di (4-pyridyl) benzene capable of bidentate coordination on the gas adsorption behavior.

JP 2000-109485 A JP 2001-348361 A JP 2006-328051 A JP 2008-208110 A JP2011-83755A

  Therefore, the objective of this invention is providing the metal complex which can be used as a gas adsorbent with much adsorption amount than before.

  The present inventors have intensively studied and developed a metal complex comprising a specific dicarboxylic acid compound (I), at least one metal ion, and an organic ligand (II) capable of bidentate coordination with the metal ion. The inventors have found that the above object can be achieved and have reached the present invention.

That is, according to the present invention, the following is provided.
(1) The following general formula (I);

(Wherein R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ and R ⁸ are the same or different and each represents a hydrogen atom, an alkyl group which may have a substituent, or an alkoxy group. , Formyl group, acyloxy group, alkoxycarbonyl group, nitro group, cyano group, amino group, monoalkylamino group, dialkylamino group, acylamino group or halogen atom, R ² and R ³ , or R ⁶ and R ⁷ Together with each other to form an alkylene group or an alkadiene group which may have a substituent.) And a dicarboxylic acid compound (I) represented by groups 2 and 7 to 12 in the periodic table. At least one metal ion selected from ions of the metal to which it belongs; and the following general formula (II):

(Wherein R ⁹ , R ¹⁰ , R ¹¹ , R ¹² , R ¹³ , R ¹⁴ , R ¹⁵ and R ¹⁶ are the same or different and each represents a hydrogen atom, an alkyl group which may have a substituent, or an alkoxy group. A formyl group, an acyloxy group, an alkoxycarbonyl group, a nitro group, a cyano group, an amino group, a monoalkylamino group, a dialkylamino group, an acylamino group or a halogen atom). Metal complexes consisting of possible organic ligands (II).
(2) The metal complex according to (1), wherein the jungle gym skeleton has a structure in which a plurality of interpenetrations occur.
(3) The metal complex according to (1) or (2), wherein the metal ion is a zinc ion.
(4) The metal complex according to any one of (1) to (3), wherein the organic ligand (II) capable of bidentate coordination is N- (4-pyridyl) isonicotinamide.
(5) An adsorbent comprising the metal complex according to any one of (1) to (4).
(6) The adsorbent is carbon dioxide, hydrogen, carbon monoxide, oxygen, nitrogen, hydrocarbon having 1 to 4 carbon atoms, rare gas, hydrogen sulfide, ammonia, sulfur oxide, nitrogen oxide, siloxane, water vapor or The adsorbent according to (5), which is an adsorbent for adsorbing organic vapor.
(7) Dicarboxylic acid compound (I), at least one metal salt selected from salts of metals belonging to Groups 2 and 7-12 of the periodic table, and an organic configuration capable of bidentate coordination with the metal ion The method for producing a metal complex according to (1), wherein the ligand (II) is reacted and precipitated in a solvent.

  According to the present invention, a specific dicarboxylic acid compound (I), at least one metal ion selected from ions of metals belonging to Groups 2 and 7 to 12 of the periodic table, and bidentate coordination to the metal ion are possible. A metal complex comprising the organic ligand (II) can be provided.

  Since the metal complex of the present invention is excellent in the adsorption performance of various gases, carbon dioxide, hydrogen, carbon monoxide, oxygen, nitrogen, hydrocarbons having 1 to 4 carbon atoms, rare gas, hydrogen sulfide, ammonia, sulfur oxidation It can be used as an adsorbent for adsorbing substances, nitrogen oxides, siloxanes, water vapor, organic vapors and the like.

It is a schematic diagram of the structural change accompanying adsorption / desorption of the metal complex of this invention. 3 is a powder X-ray diffraction pattern before vacuum drying of the metal complex obtained in Synthesis Example 1. FIG. 3 is a powder X-ray diffraction pattern after vacuum drying of the metal complex obtained in Synthesis Example 1. FIG. 3 is a powder X-ray diffraction pattern before vacuum drying of the metal complex obtained in Comparative Synthesis Example 1. FIG. 3 is a powder X-ray diffraction pattern after vacuum drying of the metal complex obtained in Comparative Synthesis Example 1. FIG. 2 is an adsorption isotherm of carbon dioxide at 273 K of the metal complexes obtained in Synthesis Example 1 and Comparative Synthesis Example 1. It is an adsorption isotherm of ethylene at 273 K of the metal complexes obtained in Synthesis Example 1 and Comparative Synthesis Example 1.

  The metal complex of the present invention comprises a dicarboxylic acid compound (I), at least one metal ion selected from ions of metals belonging to Groups 2 and 7 to 12 of the periodic table, and bidentate coordination to the metal ion. It consists of possible organic ligands (II).

  The metal complex includes a dicarboxylic acid compound (I), at least one metal salt selected from salts of metals belonging to Groups 2 and 7 to 12 of the periodic table, and an organic compound capable of bidentate coordination with the metal ion. Ligand (II) can be produced by reacting it in a solvent under normal pressure for several hours to several days, followed by precipitation. For example, an aqueous solution or an organic solvent solution of a metal salt and an organic solvent solution containing a dicarboxylic acid compound (I) and an organic ligand (II) capable of bidentate coordination are mixed and reacted under normal pressure. Thus, the metal complex of the present invention can be obtained.

  The dicarboxylic acid compound (I) used in the present invention is represented by the following general formula (I):

It is represented by In the formula, R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ and R ⁸ are the same or different and each is a hydrogen atom, an alkyl group which may have a substituent, an alkoxy group, A formyl group, an acyloxy group, an alkoxycarbonyl group, a nitro group, a cyano group, an amino group, a monoalkylamino group, a dialkylamino group, an acylamino group, or a halogen atom, R ² and R ³ , or R ⁶ and R ⁷ are An alkylene group or an alkadiene group which may have a substituent may be formed together.

Among the substituents that can constitute R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ and R ⁸ , the alkyl group or alkoxy group preferably has 1 to 5 carbon atoms. . Examples of the alkyl group include a linear or branched alkyl group such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, and a pentyl group, and an alkoxy group. Examples of methoxy group, ethoxy group, n-propoxy group, isoproxy group, n-butoxy group, isobutoxy group, tert-butoxy group, and examples of acyloxy group include acetoxy group, n-propanoyloxy group , N-butanoyloxy group, pivaloyloxy group, benzoyloxy group are examples of alkoxycarbonyl group, methoxycarbonyl group, ethoxycarbonyl group, n-butoxycarbonyl group are examples of monoalkylamino group, methylamino Examples of groups where the dialkylamino group is dimethylamino group are acyl Examples of amino group, an acetylamino group, examples of the halogen atom, fluorine atom, chlorine atom, bromine atom, iodine atom, and the like, respectively. Examples of the substituent that the alkyl group may have include an alkoxy group (methoxy group, ethoxy group, n-propoxy group, isopropoxy group, n-butoxy group, isobutoxy group, tert-butoxy group). Etc.), amino group, monoalkylamino group (such as methylamino group), dialkylamino group (such as dimethylamino group), formyl group, epoxy group, acyloxy group (acetoxy group, n-propanoyloxy group, n-butanoyl) Oxy group, pivaloyloxy group, benzoyloxy group, etc.), alkoxycarbonyl group (methoxycarbonyl group, ethoxycarbonyl group, n-butoxycarbonyl group, etc.), carboxylic anhydride group (—CO—OCO—R group) (R is carbon And an alkyl group having a number of 1 to 5). 1-3 are preferable and, as for the number of the substituents of an alkyl group, one is more preferable.

The number of carbon atoms of the alkylene group is preferably 1 or 2. When the alkylene group has 1 carbon atom, R ² and R ³ , or R ⁶ and R ⁷ together with the carbon atom to which they are bonded form a 5-membered ring (cyclopentadiene ring), and the alkylene group When R ² has 2 carbon atoms, R ² and R ³ , or R ⁶ and R ⁷ together with the carbon atom to which they are bonded form a 6-membered ring (cyclohexadiene ring).

The number of carbon atoms of the alkadiene group is preferably 2. When the alkadiene group has 2 carbon atoms, R ² and R ³ , or R ⁶ and R ⁷ together with the carbon atom to which they are bonded form a 6-membered ring (benzene ring).

  Examples of the substituent that the alkylene group or alkadiene group may have include an alkoxy group (methoxy group, ethoxy group, n-propoxy group, isopropoxy group, n-butoxy group, isobutoxy group, tert- Butoxy group, etc.), amino group, monoalkylamino group (such as methylamino group), dialkylamino group (such as dimethylamino group), formyl group, epoxy group, acyloxy group (acetoxy group, n-propanoyloxy group, n- Butanoyloxy group, pivaloyloxy group, benzoyloxy group, etc.), alkoxycarbonyl group (methoxycarbonyl group, ethoxycarbonyl group, n-butoxycarbonyl group, etc.), carboxylic acid anhydride group (—CO—O—CO—R group) (R is an alkyl group having 1 to 5 carbon atoms).

  Examples of the dicarboxylic acid compound (I) include 4,4′-biphenyldicarboxylic acid, 2,7-fluorenedicarboxylic acid, 2,7-pyrene dicarboxylic acid, and 4,5,9,10-tetrahydropyrene-2,7. -Dicarboxylic acid can be used, among which 4,4'-biphenyldicarboxylic acid is preferred.

  Examples of metal ions belonging to groups 2 and 7-12 of the periodic table used in the present invention include magnesium ions, calcium ions, manganese ions, iron ions, cobalt ions, nickel ions, copper ions, zinc ions, and cadmium ions. Among them, zinc ions are preferable. The metal ion is preferably a single metal ion, but two or more metal ions may be mixed and used. Moreover, the metal complex of this invention can also mix and use 2 or more types of metal complexes which consist of a single metal ion.

  Examples of salts of metals belonging to Groups 2 and 7-12 of the periodic table used for the production of metal complexes include magnesium salts, calcium salts, manganese salts, iron salts, cobalt salts, nickel salts, copper salts, zinc salts and A cadmium salt or the like can be used, and among them, a zinc salt is preferable. The metal salt is preferably a single metal salt, but two or more metal salts may be mixed and used. As these metal salts, organic acid salts such as acetate and formate, and inorganic acid salts such as hydrochloride, hydrobromide, sulfate, nitrate and carbonate can be used.

  The organic ligand (II) capable of bidentate coordination used in the present invention has the following general formula (II):

It is represented by In the formula, R ⁹ , R ¹⁰ , R ¹¹ , R ¹² , R ¹³ , R ¹⁴ , R ¹⁵ and R ¹⁶ are the same or different and each is a hydrogen atom, an alkyl group which may have a substituent, an alkoxy group, A formyl group, an acyloxy group, an alkoxycarbonyl group, a nitro group, a cyano group, an amino group, a monoalkylamino group, a dialkylamino group, an acylamino group, or a halogen atom.

Of the substituents that can constitute R ⁹ , R ¹⁰ , R ¹¹ , R ¹² , R ¹³ , R ¹⁴ , R ¹⁵ and R ¹⁶ , the alkyl group or alkoxy group preferably has 1 to 5 carbon atoms. . Examples of the alkyl group include a linear or branched alkyl group such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, and a pentyl group, and an alkoxy group. Examples of methoxy group, ethoxy group, n-propoxy group, isoproxy group, n-butoxy group, isobutoxy group, tert-butoxy group, and examples of acyloxy group include acetoxy group, n-propanoyloxy group , N-butanoyloxy group, pivaloyloxy group, benzoyloxy group are examples of alkoxycarbonyl group, methoxycarbonyl group, ethoxycarbonyl group, n-butoxycarbonyl group are examples of monoalkylamino group, methylamino Examples of groups where the dialkylamino group is dimethylamino group are acyl Examples of amino group, an acetylamino group, examples of the halogen atom, fluorine atom, chlorine atom, bromine atom, iodine atom, and the like, respectively. Examples of the substituent that the alkyl group may have include an alkoxy group (methoxy group, ethoxy group, n-propoxy group, isopropoxy group, n-butoxy group, isobutoxy group, tert-butoxy group). Etc.), amino group, monoalkylamino group (such as methylamino group), dialkylamino group (such as dimethylamino group), formyl group, epoxy group, acyloxy group (acetoxy group, n-propanoyloxy group, n-butanoyl) Oxy group, pivaloyloxy group, benzoyloxy group, etc.), alkoxycarbonyl group (methoxycarbonyl group, ethoxycarbonyl group, n-butoxycarbonyl group, etc.), carboxylic anhydride group (—CO—OCO—R group) (R is carbon And an alkyl group having a number of 1 to 5). 1-3 are preferable and, as for the number of the substituents of an alkyl group, one is more preferable.

  As the organic ligand (II) capable of bidentate coordination, for example, N- (4-pyridyl) isonicotinamide can be used. Here, the bidentate organic ligand means a neutral ligand having at least two sites capable of coordinating with a metal ion by a lone pair.

  The mixing ratio of the dicarboxylic acid compound (I) to the bidentate organic ligand (II) when producing the metal complex is as follows: dicarboxylic acid compound (I): bidentate organic ligand (II) = 1: 5-8: 1 is preferable, and a molar ratio of 1: 3-6: 1 is more preferable. Even if the reaction is carried out in a range other than this, the desired metal complex can be obtained, but this is not preferable because the yield is lowered and the side reaction is also increased.

  The mixing ratio of the metal salt to the bidentate organic ligand (II) when producing the metal complex is as follows: metal salt: bidentate organic ligand (II) = 3: 1 to 1 : Within the range of the molar ratio of 3: 3, and more preferably within the range of the molar ratio of 2: 1 to 1: 2. In other ranges, the yield of the target metal complex decreases, and purification of the metal complex obtained by leaving unreacted raw materials becomes difficult.

  The molar concentration of the dicarboxylic acid compound (I) in the mixed solution for producing the metal complex is preferably 0.005 to 5.0 mol / L, and more preferably 0.01 to 2.0 mol / L. Even if the reaction is performed at a concentration lower than this, the desired metal complex can be obtained, but this is not preferable because the yield decreases. If the concentration is higher than this, the solubility is lowered and the reaction does not proceed smoothly.

  The molar concentration of the metal salt in the mixed solution for producing the metal complex is preferably 0.005 to 5.0 mol / L, and more preferably 0.01 to 2.0 mol / L. Even if the reaction is performed at a concentration lower than this, the desired metal complex can be obtained, but this is not preferable because the yield decreases. Further, at a concentration higher than this, unreacted metal salt remains, and purification of the obtained metal complex becomes difficult.

  The molar concentration of the bidentate organic ligand (II) in the mixed solution for producing the metal complex is preferably 0.001 to 5.0 mol / L, and preferably 0.005 to 2.0 mol / L. More preferred. Even if the reaction is performed at a concentration lower than this, the desired metal complex can be obtained, but this is not preferable because the yield decreases. If the concentration is higher than this, the solubility is lowered and the reaction does not proceed smoothly.

  As a solvent used for producing the metal complex, an organic solvent, water, or a mixed solvent thereof can be used. Specifically, methanol, ethanol, propanol, diethyl ether, dimethoxyethane, tetrahydrofuran, hexane, cyclohexane, heptane, benzene, toluene, methylene chloride, chloroform, acetone, ethyl acetate, acetonitrile, N, N-dimethylformamide, water or These mixed solvents can be used. The reaction temperature is preferably 253 to 423K.

  The completion of the reaction can be confirmed by quantifying the remaining amount of the raw material by gas chromatography or high performance liquid chromatography. After completion of the reaction, the obtained mixed solution is subjected to suction filtration to collect a precipitate, washed with an organic solvent, and then vacuum dried at about 373 K for several hours to obtain the metal complex of the present invention.

  The metal complex of the present invention does not adsorb gas molecules when solvent molecules are adsorbed. Therefore, when used as an adsorbent, it is necessary to vacuum-dry the previously obtained metal complex to remove solvent molecules in the pores.

  The metal complex of the present invention obtained as described above is an organic ligand capable of bidentate coordination to the axial position of the metal ion in the skeleton composed of the carboxylate ion and the metal ion of the dicarboxylic acid compound (I) ( II) has a three-dimensional structure in which the jungle gym skeleton formed by coordination is multiple interpenetrating.

  In this specification, the “jungle gym skeleton” means an organic ligand capable of bidentate coordination at the axial position of the metal ion in the skeleton composed of the carboxylate ion and metal ion of the dicarboxylic acid compound (I). It is defined as a jungle gym-like three-dimensional structure formed by connecting two-dimensional lattice-like sheets composed of dicarboxylic acid compound (I) and metal ions.

  In the present specification, “a structure in which multiple jungle gym skeletons interpenetrate” is defined as a three-dimensional integrated structure in which a plurality of jungle gym skeletons penetrate each other so as to fill the pores.

  The fact that the metal complex has a structure in which the jungle gym skeleton is interpenetrated multiple times can be confirmed by, for example, single crystal X-ray structure analysis, powder X-ray crystal structure analysis, or the like.

  In the metal complex of the present invention, the structure and size of the pores in the jungle gym skeleton are changed by various external stimuli. Examples of the external stimulus include a chemical stimulus such as a substance adsorbed in the pores of the metal complex, or a physical stimulus such as temperature, pressure, and electric field.

  Examples of the substance adsorbed in the pores of the metal complex include carbon dioxide, hydrogen, carbon monoxide, oxygen, nitrogen, hydrocarbons having 1 to 4 carbon atoms, rare gases, ammonia, and other gaseous substances, or water. And liquid substances such as organic compounds that are liquid at normal temperature and pressure.

  Changes in pore structure and size due to external stimuli depend on the type of substance to be adsorbed, the adsorption pressure, and the adsorption temperature. That is, in addition to the difference in the interaction between the pore surface and the substance (the strength of the interaction is proportional to the magnitude of the Lennard-Jones potential of the substance), the degree of structural change varies depending on the adsorbed substance, and thus high selectivity To express. FIG. 1 shows a schematic diagram of the structural change accompanying adsorption / desorption. In the present invention, pore shape and fineness are obtained using the dicarboxylic acid compound (I) represented by the general formula (I) and the organic ligand (II) capable of bidentate coordination represented by the general formula (II). By controlling the charge density on the pore surface, high adsorption performance is exhibited. After the adsorbed substance is desorbed, it returns to its original structure, so the pore size also returns.

  Although the said adsorption mechanism is presumption, even if it does not follow the said mechanism, if the requirements prescribed | regulated by this invention are satisfied, it will be included in the technical scope of this invention.

  The change in the structure and size of the pores caused by external stimulation of the metal complex can be confirmed by, for example, changes in the powder X-ray diffraction pattern, changes in absorption wavelength, changes in magnetic susceptibility, and the like.

  Since the metal complex of the present invention is excellent in the adsorption performance of various gases, carbon dioxide, hydrogen, carbon monoxide, oxygen, nitrogen, hydrocarbon having 1 to 4 carbon atoms (methane, ethane, ethylene, acetylene, propane, Propene, methylacetylene, propadiene, etc.), noble gases (helium, neon, argon, krypton, xenon, etc.), hydrogen sulfide, ammonia, sulfur oxide, nitrogen oxide, siloxane (hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane) Etc.), and is preferable as an adsorbent for adsorbing water vapor or organic vapor. The organic vapor means a vaporized organic substance that is liquid at normal temperature and pressure. Examples of such organic substances include alcohols such as methanol and ethanol; amines such as trimethylamine; aldehydes such as acetaldehyde; aliphatic hydrocarbons having 5 to 16 carbon atoms; aromatic hydrocarbons such as benzene and toluene; acetone And ketones such as methyl ethyl ketone; halogenated hydrocarbons such as methyl chloride and chloroform.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention concretely, this invention is not limited to these. Analysis and evaluation in the following examples and comparative examples were performed as follows.

(1) Measurement of powder X-ray diffraction pattern Using an X-ray diffractometer, a range of diffraction angle (2θ) = 5 to 50 ° was scanned at a scanning speed of 1 ° / min, and measured by a symmetric reflection method. Details of the measurement conditions are shown below.
<Analysis conditions>
Apparatus: RINT2400 manufactured by Rigaku Corporation
X-ray source: CuKα (λ = 1.5418Å) 40 kV 200 mA
Goniometer: Vertical goniometer Detector: Scintillation counter Step width: 0.02 °
Slit: Divergent slit = 0.5 °
Receiving slit = 0.15mm
Scattering slit = 0.5 °

(2) Creation of adsorption isotherm A gas adsorption amount was measured by a volumetric method (based on JIS Z8831-2) using a gas adsorption amount measuring device, and an adsorption isotherm was created. At this time, prior to the measurement, the sample was dried at 373 K and 50 Pa for 10 hours to remove adsorbed water and the like. Details of the measurement conditions are shown below.
<Analysis conditions>
Apparatus: BELSORP-HP manufactured by Nippon Bell Co., Ltd.
Equilibrium waiting time: 500 seconds

<Synthesis Example 1>
Under a nitrogen atmosphere, zinc nitrate hexahydrate 2.19 g (7.4 mmol), 4,4′-biphenyldicarboxylic acid 1.79 g (7.4 mmol) and N- (4-pyridyl) isonicotinamide 0.733 g ( 3.7 mmol) was dissolved in 300 mL of N, N-dimethylformamide and stirred at 393 K for 24 hours. As a result of the single crystal X-ray structural analysis of the deposited metal complex, the obtained metal complex had a three-dimensional structure in which the jungle gym skeleton was double interpenetrated. The powder X-ray diffraction pattern of the obtained metal complex is shown in FIG. The precipitated metal complex was recovered by suction filtration, and then washed with methanol three times. Then, it dried at 373 K and 50 Pa for 8 hours, and obtained 2.55 g (yield 86%) of the target metal complex. The powder X-ray diffraction pattern of the obtained metal complex is shown in FIG. From the comparison between FIG. 2 and FIG. 3, the powder X-ray diffraction patterns are different before and after the adsorption and desorption of the synthetic solvent. Therefore, the structure of the present metal complex is dynamically changed with the adsorption and desorption of the synthetic solvent as an external stimulus. I understand that.

<Comparative Synthesis Example 1>
Under a nitrogen atmosphere, zinc nitrate hexahydrate 2.81 g (9.5 mmol), 4,4′-biphenyldicarboxylic acid 2.29 g (9.5 mmol) and 4,4′-bipyridyl 0.739 g (4.7 mmol) Was dissolved in 800 mL of a mixed solvent of N, N-dimethylformamide and ethanol having a volume ratio of N, N-dimethylformamide: ethanol = 1: 1 and stirred at 363 K for 48 hours. As a result of the single crystal X-ray structural analysis of the deposited metal complex, the obtained metal complex had a three-dimensional structure in which the jungle gym skeleton was double interpenetrated. The powder X-ray diffraction pattern of the obtained metal complex is shown in FIG. The precipitated metal complex was recovered by suction filtration, and then washed with methanol three times. Then, it dried at 373K and 50 Pa for 8 hours, and obtained the target metal complex 3.24g (yield 89%). FIG. 5 shows a powder X-ray diffraction pattern of the obtained metal complex. From the comparison between FIG. 4 and FIG. 5, the powder X-ray diffraction patterns are different before and after the adsorption and desorption of the synthetic solvent. Therefore, the structure of this metal complex dynamically changes with the adsorption and desorption of the synthetic solvent as an external stimulus. I understand that.

<Example 1>
For the metal complex obtained in Synthesis Example 1, the amount of carbon dioxide adsorbed at 273 K was measured by the volumetric method, and an adsorption isotherm was created. The results are shown in FIG.

<Comparative Example 1>
For the metal complex obtained in Comparative Synthesis Example 1, the amount of carbon dioxide adsorbed at 273K was measured by the volumetric method, and an adsorption isotherm was created. The results are shown in FIG.

  FIG. 6 shows that the metal complex of the present invention has a large amount of carbon dioxide adsorbed, and the difference is particularly remarkable in the low pressure region, so that it is excellent as a carbon dioxide adsorbing material.

<Example 2>
For the metal complex obtained in Synthesis Example 1, the amount of ethylene adsorbed at 273 K was measured by the volumetric method, and an adsorption isotherm was created. The results are shown in FIG.

<Comparative example 2>
For the metal complex obtained in Comparative Synthesis Example 1, the amount of ethylene adsorbed at 273 K was measured by the volumetric method, and an adsorption isotherm was prepared. The results are shown in FIG.

  FIG. 7 shows that the metal complex of the present invention has a large amount of ethylene adsorbed and is particularly excellent as an adsorbent for ethylene because the difference is particularly remarkable in the low pressure region.

  From the results of Examples 1 and 2 and Comparative Examples 1 and 2, the metal complex obtained in Synthesis Example 1 that satisfies the constituent requirements of the present invention also has a three-dimensional structure in which jungle gym skeletons are interpenetrated multiple times, and externally. Although the structure is dynamically changed by stimulation, it is clear that the adsorption performance of various gases is superior to the metal complex obtained in Comparative Synthesis Example 1 that does not satisfy the constituent requirements of the present invention. The reason why such a difference occurs is not always clear, but by using the constituent ligands of the metal complex of the present invention, the interaction between the gas molecules and the pore surface is increased, so that excellent gas adsorption performance is achieved. This is thought to be due to expression.

Claims (7)

The following general formula (I);

(Wherein R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ and R ⁸ are the same or different and each represents a hydrogen atom, an alkyl group which may have a substituent, or an alkoxy group. , Formyl group, acyloxy group, alkoxycarbonyl group, nitro group, cyano group, amino group, monoalkylamino group, dialkylamino group, acylamino group or halogen atom, R ² and R ³ , or R ⁶ and R ⁷ Together with each other to form an alkylene group or an alkadiene group which may have a substituent.) And a dicarboxylic acid compound (I) represented by groups 2 and 7 to 12 in the periodic table. At least one metal ion selected from ions of the metal to which it belongs; and the following general formula (II):

(Wherein R ⁹ , R ¹⁰ , R ¹¹ , R ¹² , R ¹³ , R ¹⁴ , R ¹⁵ and R ¹⁶ are the same or different and each represents a hydrogen atom, an alkyl group which may have a substituent, or an alkoxy group. A formyl group, an acyloxy group, an alkoxycarbonyl group, a nitro group, a cyano group, an amino group, a monoalkylamino group, a dialkylamino group, an acylamino group, or a halogen atom). Metal complexes consisting of possible organic ligands (II).   The metal complex according to claim 1, wherein the jungle gym skeleton has a structure in which a plurality of interpenetrations occur.   The metal complex according to claim 1 or 2, wherein the metal ion is a zinc ion. The metal complex according to any one of claims 1 to 3, wherein the bidentate organic ligand (II) is N- (4-pyridyl) isonicotinamide. An adsorbent comprising the metal complex according to claim 1. The adsorbent is carbon dioxide, hydrogen, carbon monoxide, oxygen, nitrogen, hydrocarbon having 1 to 4 carbon atoms, rare gas, hydrogen sulfide, ammonia, sulfur oxide, nitrogen oxide, siloxane, water vapor or organic vapor. The adsorbent according to claim 5, which is an adsorbent for adsorbing.   A dicarboxylic acid compound (I), at least one metal salt selected from salts of metals belonging to Groups 2 and 7-12 of the periodic table, and an organic ligand capable of bidentate coordination with the metal ion ( The method for producing a metal complex according to claim 1, wherein II) is reacted in a solvent and precipitated.

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