Method for producing polynuclear metal compounds

Abstract

To provide a novel polynuclear metal compound having great potential as a catalyst or the like.SOLUTION: The present invention discloses a method for producing a polynuclear metal compound having a metal atom different from a hetero atom and a poly atom introduced to a deficient structure site of a polyoxomethalate compound. The production method includes a step of reacting the polyoxomethalate compound (A), in which a hetero atom is coordinated with at least one poly atom selected from a group consisting of Mo, V, Nb, and Ta via an oxygen atom and an unshared electron pair-bearing compound is introduced to the deficient structure site, with a compound (B) having a metal atom different from the hetero atom and the poly atom.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a method for producing a polynuclear metal compound, more specifically to a polynuclear metal compound that may be suitably used as a catalyst, medicine, functional material, etc., and a method for producing the same. [Background technology]

[0002] Polyoxometalates are attractive materials in various fields such as catalysis, medicine, and functional materials due to their high stability and easily tunable chemical and physical properties. For this reason, there is a demand for the development of polyoxometalates with new structures.

[0003] Some polyoxometalates have unstable structures derived from defective polyoxometalates. For example, molybdenum oxide clusters are extremely unstable compared to tungsten oxide clusters, which have been widely studied. As a result, there are few reports of research based on molybdenum oxide clusters, and in particular, there are no reports of their application to the structural design of polynuclear metal compounds.

[0004] As a report on the stabilization of normally unstable defective polyoxometalates, the phosphorus molybdenum oxide cluster [PMo9O 34 ] 9- By coordinating pyridine (py) to the polyoxometalate [PMo9O 31 (py)3] 3- It has also been reported that a dimeric polyoxometalate (II) can be obtained from anionic polyoxometalate I and 4,4'-bipyridine, and a tetrameric polyoxometalate (III) can be obtained from anionic polyoxometalate I and 5,10,15,20-tetra(4-pyridyl)porphyrin (see Non-Patent Document 1). [Prior art documents] [Non-patent literature]

[0005] [Non-Patent Document 1] Chifeng Li et al. and 3 others, Journal of the American Chemical Society (USA), 2019, Vol. 141, pp. 7687-7692 Summary of the Invention [Problem to be solved by the invention]

[0006] As described above, there is a need for further development of polyoxometalates with new structures, and it has been desirable to make better use of the diverse properties that are exhibited depending on the type and coordination state of the metal atoms. The present invention has been made in view of the above-mentioned circumstances, and has an object to provide a novel metal compound which is promising as a catalyst or the like. [Means for solving the problem]

[0007] The present inventors have investigated methods for producing metal compounds and have found that a novel polynuclear metal compound can be obtained by reacting a polyoxometalate compound having a structure in which a non-shared electron pair-containing compound is introduced at the defective structural site of a defective polyoxometalate containing a specific polyatom with a compound containing a metal atom other than the heteroatom and the polyatom, thereby arriving at the present invention.

[0008] That is, the present invention is a method for producing a polynuclear metal compound having a structure in which a metal atom other than a heteroatom and a polyatom is introduced into the defective structural site of a polyoxometalate compound, the method comprising the step of reacting a polyoxometalate compound (A) having a structure in which at least one polyatom selected from the group consisting of Mo, V, Nb, and Ta is coordinated to the heteroatom via an oxygen atom, and a non-shared electron pair-containing compound is introduced into the defective structural site, with a compound (B) containing a metal atom other than a heteroatom and a polyatom.

[0009] The present invention also relates to a polynuclear metal compound having a structure in which a metal atom other than a heteroatom and a polyatom is introduced into the defective structural site of a polyoxometalate compound, and the polynuclear metal compound has a structure in which at least one polyatom selected from the group consisting of Mo, V, Nb, and Ta is coordinated to the heteroatom via an oxygen atom. The present invention will be described in detail below. In addition, a combination of two or more of the individual preferred embodiments of the present invention described below is also a preferred embodiment of the present invention.

[0010] <Method of producing the polynuclear metal compound of the present invention> The method for producing a polynuclear metal compound of the present invention includes a step of reacting a polyoxometalate compound (A) having a structure in which at least one polyatom selected from the group consisting of Mo, V, Nb, and Ta is coordinated to a heteroatom via an oxygen atom and an unshared electron pair-containing compound is introduced into the defective structural site, with a compound (B) containing a metal atom different from the heteroatom and the polyatom. In this specification, a compound having two or more metal atoms different from heteroatoms and polyatoms is referred to as a polynuclear metal compound. The metal atoms may be of one type or of two or more types. First, the raw material compounds and preferred reaction conditions in the reaction steps will be described below.

[0011] The polyatom in the polyoxometalate compound (A) is preferably at least one selected from the group consisting of Mo, V, Nb, and Ta, and more preferably Mo.

[0012] The heteroatom in the polyoxometalate compound (A) is preferably at least one selected from the group consisting of Si, P, Al, S, Ge, As, and Se. Among them, Si and / or P are more preferred, and P is even more preferred.

[0013] The polyoxometalate compound (A) has a structure in which a non-shared electron pair-containing compound is introduced into the defective structure site, meaning that the oxygen atom or a group containing an oxygen atom (e.g., -OH2 group) in the defective structure site is replaced with an atom having a non-shared electron pair in the non-shared electron pair-containing compound. It is not necessary that the compound has actually undergone a substitution reaction, and it is sufficient that the compound has a similar structure. The number of defective structure sites in the polyoxometalate compound (A) is usually two or more, and the polyoxometalate compound (A) is preferably a two-deficient type or a three-deficient type. For example, the polyoxometalate compound (A) may have a structure in which two defective structure sites are originally present and a non-shared electron pair-containing compound is introduced into at least one of the two defective structure sites, or may have a structure in which three defective structure sites are originally present and a non-shared electron pair-containing compound is introduced into at least one of the three defective structure sites. In particular, the polyoxometalate compound (A) preferably has a structure in which a non-shared electron pair-containing compound is introduced into at least two of the defective structure sites, and more preferably has a structure in which a non-shared electron pair-containing compound is introduced into all of the defective structure sites. The polyoxometalate compound (A) has a structure in which a non-shared electron pair-containing compound is introduced into the defective structural site, and therefore is stable in a solvent, and side reactions are sufficiently suppressed, and isomerization is thought to be suppressed. By subjecting such a polyoxometalate compound (A) to the above reaction process, a novel polynuclear metal compound can be produced.

[0014] The lone electron pair-containing compound in the polyoxometalate compound (A) is a compound containing an atom having a lone electron pair, and the oxygen atom or a group containing an oxygen atom that is easily dislodged from the defective structure site is replaced with this compound, thereby contributing to the stabilization of the polyoxometalate. In a structure in which the lone electron pair-containing compound is introduced into the defective structure site, the lone electron pair-containing compound may be introduced while maintaining the structure of the raw material lone electron pair-containing compound as it is, or may be introduced in a form in which the structure of the raw material lone electron pair-containing compound has been changed, but it is preferable that the structure of the raw material lone electron pair-containing compound is introduced while maintaining the structure of the raw material lone electron pair-containing compound as it is.

[0015] Suitable examples of the atom having an unshared electron pair contained in the unshared electron pair-containing compound include a nitrogen atom, an oxygen atom, a phosphorus atom, and a sulfur atom, and among these, a nitrogen atom is more preferred. That is, the unshared electron pair-containing compound is preferably a nitrogen atom-containing compound. Suitable examples of the nitrogen atom-containing compound include primary amines, secondary amines, and nitrogen-containing heterocyclic aromatic compounds, with nitrogen-containing heterocyclic aromatic compounds being more preferred. Preferred examples of the nitrogen-containing heterocyclic aromatic compound include pyrrole, pyrazole, imidazole, pyridine, pyridazine, pyrimidine, pyrazine, etc. Among these, pyridine is more preferred. In this specification, the unshared electron pair-containing compound introduced into the defective structural site of the polyoxometalate compound (A) can be rephrased as an unshared electron pair-containing group, and the nitrogen-containing heterocyclic aromatic compound introduced into the defective structural site can be rephrased as a nitrogen-containing heterocyclic aromatic group.

[0016] The polyoxometalate compound (A) generally forms a salt, and the cation (counter cation) for forming the salt may be either an inorganic cation or an organic cation. Examples of inorganic cations include alkali metal cations, alkaline earth metal cations, transition metal cations, typical metal cations, protons, ammonium, etc., and one or more of these can be used. The organic cation includes organic ammonium, organic phosphonium, etc., and one or more of these can be used. Among these, the counter cation is preferably an organic cation. The organic cation preferably has 4 to 48 carbon atoms, more preferably 4 to 40 carbon atoms, and further preferably 4 to 30 carbon atoms.

[0017] The organic ammonium is preferably a quaternary organic ammonium. Examples of the quaternary organic ammonium include tetramethylammonium, tetraethylammonium, tetrapropylammonium, tetrabutylammonium, tributylmethylammonium, trioctylmethylammonium, trilaurylmethylammonium, benzyltrimethylammonium, benzyltriethylammonium, benzyltributylammonium, cetylpyridinium, and the like, and one or more of these can be used.

[0018] The organic phosphonium is preferably a quaternary organic phosphonium, such as tetramethylphosphonium, tetraethylphosphonium, tetrabutylphosphonium, tetraphenylphosphonium, ethyltriphenylphosphonium, and benzyltriphenylphosphonium, and one or more of these may be used.

[0019] In the manufacturing method of the present invention, the metal atom in the compound (B) having a metal atom different from the heteroatom and polyatom is preferably at least one selected from the group consisting of 3d transition metal atoms, 4d transition metal atoms, 5d transition metal atoms, and rare earth elements. In other words, the metal atom different from the heteroatom and polyatom is preferably at least one selected from the group consisting of Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Hf, Ta, W, Re, Os, Ir, Pt, Au, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu. In the production method of the present invention, a stable polyoxometalate compound (A) is used as a raw material, and by reacting this with the above-mentioned compound (B), it is possible to appropriately introduce metal atoms derived from compound (B) that are known to be heterometals in polyoxometalates.

[0020] Examples of the 3d transition metal atom include Sc, Ti, V, Cr, Mn, Fe, Co, Ni, and Cu. Among them, V, Mn, Fe, Co, and Ni are preferred, and V and Mn are more preferred. Examples of the 4d transition metal atom include Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, and Ag, and among these, Y, Ru, Rh, Pd, and Ag are preferred. Examples of the 5d transition metal atom include Hf, Ta, W, Re, Os, Ir, Pt, and Au, and among these, Hf, Ta, and W are preferred. Examples of the rare earth elements include La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu, and among these, Ce, Sm, Eu, Gd, Tb, and Dy are preferred.

[0021] The compound (B) having a metal atom different from the heteroatom and the polyatom preferably contains at least one group selected from the group consisting of a carboxylate group, a trifluoromethanesulfonate group, and an acetylacetonate group, of which the acetylacetonate group is more preferred.

[0022] Particularly preferred examples of the compound (B) having a metal atom different from the heteroatom and polyatom include vanadyl acetylacetonate, manganese acetylacetonate, iron acetylacetonate, cobalt acetylacetonate, nickel acetylacetonate, palladium acetylacetonate, silver acetylacetonate, lanthanum acetylacetonate, and terbium acetylacetonate, and one or more of these can be used.

[0023] The production method of the present invention is not particularly limited as long as it includes a step of reacting the above-mentioned specific polyoxometalate compound (A) with a compound (B) containing a metal atom different from the heteroatoms and polyatoms. A suitable production method includes mixing the polyoxometalate compound (A) and the compound (B) containing a metal atom different from the heteroatoms and polyatoms in an organic solvent or a solvent containing an organic solvent when reacting the polyoxometalate compound (A) with the compound (B) containing a metal atom different from the heteroatoms and polyatoms. Here, the polyoxometalate compound (A) can be added as a powder or as a solution to a liquid in which the compound (B) containing a metal atom different from the heteroatoms and polyatoms is dispersed or dissolved, to produce the polynuclear metal compound. The polyoxometalate compound (A) and the compound (B) containing a metal atom different from the heteroatoms and polyatoms may be added to the solvent at the same time. The polyoxometalate compound (A) may be added all at once or gradually. The polynuclear metal compound may be produced in a single step or in multiple steps. For example, a method may be used in which the product is once removed without mixing a portion of the predetermined amount of polyoxometalate compound (A) or compound (B), the product is redissolved in a solvent, and the remaining polyoxometalate compound (A) or compound (B) is then mixed therein.

[0024] The molar ratio of polyoxometalate compound (A) to compound (B) in the above reaction step may be appropriately set depending on the number of metal atoms different from the heteroatoms and polyatoms contained in compound (B) and the number of said metal atoms to be introduced into one polyoxometalate compound (A). For example, the molar ratio is preferably 1:1 to 1:10, more preferably 2:3 to 1:9, and even more preferably 1:2 to 1:8.

[0025] In the reaction step, it is also preferable to react the polyoxometalate compound (A) with the compound (B) so that the ratio of the number of unshared electron pair-containing compounds in the polyoxometalate compound (A) to the number of metal atoms other than heteroatoms and polyatoms in the compound (B) is, for example, 1:10 to 10:1. This ratio is more preferably 1:5 to 5:1, and even more preferably 1:2 to 2:1.

[0026] In the above reaction step, the mixing time of the polyoxometalate compound (A) and the compound (B) is preferably 1 minute or more from the viewpoint of sufficiently introducing the compound (B) into the defective structural sites of the polyoxometalate compound (A). The mixing time is more preferably 10 minutes or more, and even more preferably 20 minutes or more. The mixing time is preferably 72 hours or less. More preferably, the mixing time is 48 hours or less, even more preferably 24 hours or less, and particularly preferably 3 hours or less. The mixing time mainly means the time during which the polyoxometalate compound (A) and the compound (B) coexist and are mixed in a homogeneous solution. For example, it refers to the time from the time when the polyoxometalate compound (A) is added to the solution containing the compound (B) to the time when an inorganic salt, an organic salt, or a poor solvent is added to precipitate the polynuclear metal compound. Mixing can be performed using a commercially available stirrer or the like. If impurities precipitate during mixing, they can be removed by filtration or the like as necessary. The setting of the mixing time is one of the important factors that determine the structure of the polynuclear metal compound, and may be appropriately set within the above range depending on the type of element introduced by the compound (B). The polynuclear metal compound can be purified by recrystallization or the like. It can also be prepared and stored in the system without isolation, and used as a catalyst or the like as it is.

[0027] In the above reaction step, the temperature at which the polyoxometalate compound (A) and the compound (B) are mixed is preferably 0° C. or higher, more preferably 10° C. or higher, and even more preferably 15° C. or higher. The temperature is preferably 150° C. or lower, more preferably 100° C. or lower, and even more preferably 60° C. or lower. The above reaction step can be carried out under increased pressure, normal pressure, or reduced pressure.

[0028] As described below, an acid may be added during or after mixing of polyoxometalate compound (A) and compound (B). Alternatively, a method may be used in which polyoxometalate compound (A) or compound (B) is mixed to introduce an element derived from compound (B) into polyoxometalate compound (A), and then polyoxometalate compound (A) or compound (B) is further added to obtain a polynuclear metal compound. Alternatively, a method can be used in which a compound obtained by introducing an element derived from compound (B) into one polyoxometalate compound (A) is dissolved in a solvent to obtain a compound, to which a compound obtained by introducing an element derived from compound (B) into one polyoxometalate compound (A) is further added, and a poor solvent is then added to obtain a polynuclear metal compound.

[0029] The solvent preferably contains an organic solvent. The solvent containing an organic solvent may contain other components as long as it contains an organic solvent, but one of the preferred forms of the solvent containing an organic solvent is a mixed solvent of an organic solvent and water. The volume ratio of the organic solvent to water in the above solvent is not particularly limited, but is preferably 100:0 to 30:70, more preferably 100:0 to 50:50, and even more preferably 100:0 to 70:30.

[0030] The organic solvent is not particularly limited, and examples thereof include one or more of acetone, acetonitrile, benzonitrile, methanol, ethanol, propanol, butanol, chloroform, dichloroethane, hexane, octane, benzene, toluene, xylene, ethyl acetate, butyl acetate, propylene carbonate, diethyl ether, dibutyl ether, diisopropyl ether, dioxane, tetrahydrofuran, cyclopentyl methyl ether, methyl ethyl ketone, methyl isobutyl ketone, dimethylformamide, dimethylacetamide, dimethylsulfoxide, and nitromethane. Among these, acetone, acetonitrile, benzonitrile, methanol, ethanol, butanol, dichloroethane, hexane, octane, toluene, xylene, ethyl acetate, butyl acetate, propylene carbonate, diethyl ether, dioxane, tetrahydrofuran, cyclopentyl methyl ether, methyl ethyl ketone, methyl isobutyl ketone, dimethylformamide, dimethylacetamide, dimethyl sulfoxide, and nitromethane are preferred, and acetone, acetonitrile, benzonitrile, methanol, ethanol, butanol, dichloroethane, toluene, xylene, ethyl acetate, butyl acetate, propylene carbonate, diethyl ether, dioxane, tetrahydrofuran, methyl ethyl ketone, methyl isobutyl ketone, dimethylformamide, dimethyl sulfoxide, and nitromethane are more preferred. Even more preferred are acetone, acetonitrile, benzonitrile, butanol, toluene, ethyl acetate, butyl acetate, propylene carbonate, dichloroethane, diethyl ether, methyl isobutyl ketone, dimethylformamide, dimethyl sulfoxide, and nitromethane.

[0031] As the poor solvent, one or more of hexane, octane, benzene, toluene, xylene, ethyl acetate, butyl acetate, propylene carbonate, diethyl ether, dibutyl ether, diisopropyl ether, dioxane, tetrahydrofuran, cyclopentyl methyl ether, methyl ethyl ketone, methyl isobutyl ketone, dichloroethane, chloroform, and the like can be used.

[0032] The volume of the solvent is preferably 1 mL or more per 1 mmol of the polyoxometalate compound (A), more preferably 10 mL or more, and even more preferably 20 mL or more. Also, the volume is preferably 5000 mL or less, more preferably 2500 mL or less, and even more preferably 1000 mL or less.

[0033] As described above, an acid may be further mixed when or after polyoxometalate compound (A) and compound (B) are mixed, and preferably, the acid is mixed after polyoxometalate compound (A) and compound (B) are mixed. The acid that can be used includes inorganic acids such as nitric acid, hydrochloric acid, sulfuric acid, phosphoric acid, and boric acid, as well as organic acids such as p-toluenesulfonic acid, acetic acid, benzoic acid, and malonic acid. The amount of the acid used is preferably 0.01 moles or more, more preferably 0.1 moles or more, and even more preferably 1 mole or more, relative to 1 mole of the polyoxometalate compound (A), and is preferably 100 moles or less, more preferably 50 moles or less, and even more preferably 10 moles or less.

[0034] The production method of the present invention may be a stepwise production method in which a polynuclear metal compound is produced by the above-mentioned method and then another operation is performed on the polynuclear metal compound. By such a stepwise production method, a polynuclear metal compound containing two or more kinds of metal atoms different from heteroatoms and polyatoms, or a polynuclear metal compound having a specific structure can be produced.

[0035] Also suitable is a multi-step production method in which the obtained polynuclear metal compound is dissolved in an organic solvent, a counter cation is added and the mixture is stirred, and then the solvent is removed to obtain a solid, which is then recrystallized in the presence of a specific organic solvent.

[0036] Also suitable is a multi-step production method in which a polynuclear metal compound having one type of metal atom different from heteroatoms and polyatoms is produced, then the polynuclear metal compound is dissolved in an organic solvent, and a compound of a metal atom different from the metal atom possessed by the polynuclear metal compound is added to the obtained solution and stirred to produce a polynuclear metal compound having two or more types of metal atoms as metal atoms different from heteroatoms and polyatoms. By such a production method, a polynuclear metal compound having two or more types of metal atoms different from heteroatoms and polyatoms can be produced.

[0037] The production method of the present invention may further include a step of reacting a compound having a structure in which at least one polyatom selected from the group consisting of Mo, V, Nb, and Ta is coordinated to a heteroatom via an oxygen atom with a non-shared electron pair-containing compound to obtain the above-mentioned polyoxometalate compound (A).

[0038] The polynuclear metal compound of the present invention can be suitably obtained by the production method of the present invention. The polynuclear metal compound of the present invention will be described below.

[0039] <Polynuclear metal compound of the present invention> The polynuclear metal compound of the present invention is a polynuclear metal compound having a structure in which a metal atom other than a heteroatom and a polyatom is introduced into the defective structural site of a polyoxometalate compound, and the polynuclear metal compound has a structure in which at least one polyatom selected from the group consisting of Mo, V, Nb, and Ta is coordinated to the heteroatom via an oxygen atom. In addition, when it is not possible to distinguish whether the two or more types of metal atoms contained in a polynuclear metal compound are polyatoms or metal atoms different from the heteroatoms and polyatoms introduced into the defective structure sites, one of them can be a polyatom and the others can be metal atoms different from the heteroatoms and polyatoms.

[0040] The polynuclear metal compound of the present invention has a structure in which a metal atom different from a heteroatom and a polyatom is introduced into the defective structure site of the polyoxometalate compound, and this usually means that the compound has a structure in which an atom such as an oxygen atom in the defective structure site is directly or indirectly bonded to a metal atom different from a heteroatom and a polyatom. In particular, it is preferable that the oxygen atom in the defective structure site is directly bonded to a metal atom different from a heteroatom and a polyatom. The number of defective structure sites in the polyoxometalate compound is usually two or more, and the polyoxometalate compound is preferably a two-defect type or a three-defect type. For example, the polyoxometalate compound may be originally a two-defect type having a structure in which a metal atom different from a heteroatom and a polyatom is introduced into each of the two defective structure sites, or may be originally a three-defect type having a structure in which a metal atom different from a heteroatom and a polyatom is introduced into at least two of the three defective structure sites. The above-mentioned polyoxometalate compound usually has a structure in which a metal atom other than a heteroatom and a polyatom is introduced into at least two defect structure sites, and it is preferable that the polyoxometalate compound has a structure in which a metal atom other than a heteroatom and a polyatom is introduced into all defect structure sites.

[0041] The polynuclear metal compound of the present invention contains a heteropolyoxometalate anion in its crystal structure. The polyatom in the heteropolyoxometalate anion is at least one selected from the group consisting of Mo, V, Nb, and Ta. The heteroatom is preferably at least one selected from the group consisting of Si, P, Al, S, Ge, As, and Se. Such a heteropolyoxometalate anion has a crystal structure called a Keggin type in which 9 to 11 polyatoms are coordinated to the heteroatom via oxygen.

[0042] When the polyoxometalate compound is of the two-deficient type, the heteropolyoxometalate anion has the following general formula (1): [QZ 10 O j ] k- (1) (wherein Q represents a heteroatom; Z, which may be the same or different, represents a polyatom selected from Mo, V, Nb, or Ta; j and k are positive numbers, and k is determined by the valences of Q and Z). When the polyoxometalate compound is a three-deficient type, the heteropolyoxometalate anion has the following general formula (2): [QZ9O m ] n- (2) (wherein Q represents a heteroatom; Z, which may be the same or different, represents a polyatom selected from Mo, V, Nb, or Ta; m and n are positive numbers, and n is determined by the valences of Q and Z).

[0043] Here, in the general formulae (1) and (2), a Keggin type heteropolyoxometalate anion in which Z is Mo is more preferred. That is, in the polynuclear metal compound of the present invention, a polyatom thereof is Mo, which is also one of the preferred embodiments of the present invention.

[0044] Furthermore, the Keggin type heteropolyoxometalate anion preferably has an isomeric structure of α, β, or γ. In the case of a two-deficient type, the Keggin type heteropolyoxometalate anion is, for example, an α-PMo 10 O 36 ] 7- and / or [β-PMo 10 O 36 ] 7- and / or [γ-PMo 10 O 36 ] 7- , or [α-SiMo 10 O 36 ] 8- and / or [β-SiMo 10 O 36 ] 8- and / or [γ-SiMo 10 O 36 ]8- , or [α-GeMo 10 O 36 ] 8- and / or [β-GeMo 10 O 36 ] 8- and / or [γ-GeMo 10 O 36 ] 8- More preferably, [γ-PMo 10 O 36 ] 7- , [γ-SiMo 10 O 36 ] 8- or [γ-GeMo 10 O 36 ] 8- Examples include: In the case of the three-deficient type, the Keggin type heteropolyoxometalate anion is, for example, an anion represented by the general formula (2) in which Q is P, Si, or Ge [α-PMo9O 34 ] 9- and / or [β-PMo9O 34 ] 9- and / or [γ-PMo9O 34 ] 9- , or [α-SiMo9O 34 ] 10- and / or [β-SiMo9O 34 ] 10- and / or [γ-SiMo9O 34 ] 10- , or [α-GeMo9O 34 ] 10- and / or [β-GeMo9O 34 ] 10- and / or [γ-GeMo9O 34 ] 10- Examples include: Preferably, [α-PMoO 34 ] 9- , [α-SiMoO 34 ] 10- or [α-GeMo9O 34 ] 10- and particularly preferably, Q is phosphorus or silicon [α-PMo9O 34 ] 9- or [α-SiMo9O 34 ]10- It is.

[0045] Furthermore, when the polynuclear metal compound of the present invention has one structural moiety derived from a heteropolyoxometalate compound, the heteropolyoxometalate anion contained in the polynuclear metal compound has a structure represented by the following general formula (3); [QR p Z9O q ] r- (3) (wherein Q represents a heteroatom; Z, which may be the same or different, represents a polyatom selected from Mo, V, Nb, or Ta; R represents a metal atom different from the heteroatom and the polyatom; p, q, and r are positive numbers, and r is determined by the valences of Q, R, and Z).

[0046] The heteropolyoxometalate anion is, for example, a compound represented by the general formula (3) in which Q is P, Si or Ge, Z is Mo, and R is V, such as α-PV4Mo9O 41 ] 3- and / or [β-PV4Mo9O 41 ] 3- and / or [γ-PV4Mo9O 41 ] 3- , or [α-SiV4Mo9O 41 ] 4- and / or [β-SiV4Mo9O 41 ] 4- and / or [γ-SiV4Mo9O 41 ] 4- , or [α-GeV4Mo9O 41 ] 4- and / or [β-GeV4Mo9O 41 ] 4- and / or [γ-GeV4Mo9O 41 ] 4- Examples include:

[0047] The polynuclear metal compound of the present invention may be in the form of a salt. As the counter cation forming the salt, those mentioned above as the counter cation for forming the polyoxometalate compound (A) are preferably mentioned.

[0048] The polynuclear metal compound of the present invention can be used as a catalyst for organic reactions such as various oxidation reactions and acid-base reactions, etc. It is also expected to be used in various fields such as medicine and functional materials. Effect of the Invention

[0049] The method for producing a polynuclear metal compound of the present invention is capable of obtaining a novel polynuclear metal compound which is expected to be used in various fields such as catalysts, medicines, and functional materials. [Brief description of the drawings]

[0050] [Figure 1] FIG. 1 is a schematic diagram showing an outline of the production method of the present invention. [Diagram 2] 2(a) shows a polyhedron diagram of the single crystal of the manganese hexanuclear structure synthesized in Example 1. FIG. 2(b) shows an anisotropic temperature factor diagram of the single crystal of the manganese hexanuclear structure synthesized in Example 1. [Diagram 3] 3(a) shows a polyhedron diagram of the single crystal of the vanadium tetranuclear structure synthesized in Example 2. FIG. 3(b) shows an anisotropic temperature factor diagram of the single crystal of the vanadium tetranuclear structure synthesized in Example 2. [Figure 4] 4(a) shows the 31P-NMR spectrum of the vanadium tetranuclear structure compound synthesized in Example 2. FIG. 4(b) shows the 51V-NMR spectrum of the vanadium tetranuclear structure compound synthesized in Example 2. [Diagram 5] FIG. 5 shows the results of mass spectrometry of the vanadium tetranuclear structure compound synthesized in Example 2. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0051] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. Unless otherwise specified, "parts" means "parts by weight" and "%" means "% by mass." "TBA" is an abbreviation for tetra-n-butylammonium, "acac" is an abbreviation for acetylacetonate, and "py" is an abbreviation for pyridine.

[0052] For X-ray crystal structure analysis, diffraction data was acquired using a Rigaku MicroMax-007 Saturn724 and analyzed using SHELXL-2014. Mass spectrometry was performed using a JEOL JMS-T100CS. 31 P-NMR measurement and 51 V-NMR measurements were performed using a JEOL JNM-ECA500 with H3PO4 in D2O and NaVO3 in D2O as external standards. IR measurements were performed using a JASCO FT / IR-4100.

[0053] (Example 1) Synthesis of Mn hexanuclear compound Compound I (TPP3[A-α-PMo9O 31 (py)3], TPP salt (TPP=tetra-phenylphosphonium; 500 mg, 0.19 mmol) and manganese acetylacetonate Mn(acac)2 (143 mg, 0.57 mmol, 3 equivalents to compound I) were mixed, and the solution was stirred at 50°C for 2 hours. After the reaction, the solution was filtered through a membrane filter, and diethyl ether (5.0 mL) was added and allowed to stand at room temperature. After one day, a single crystal of a Mn hexanuclear structure compound suitable for single crystal X-ray structure analysis was obtained from this solution (104 mg, 21% yield).

[0054] The mass spectrometry (MS) measurement results of the obtained crystals are as follows. Positive-ion MS (ESI, acetonitrile): Found m / z = 3059.814 (Calculated m / z = 3059.837; [TPP8{Mn(acac)}2Mn4(PMo9O34 )2] 2+ ). The results of X-ray structural analysis of the obtained crystals are shown in Table 1.

[0055] [Table 1]

[0056] Representative bond lengths and angles of the single crystal of the Mn hexanuclear structure compound are shown in Table 2.

[0057] [Table 2]

[0058] (Example 2) Synthesis of V tetranuclear compound Vanadyl acetylacetonate (VO(acac), 212 mg, 0.80 mmol) was dispersed in acetone (10 mL), and the solution was mixed with water (0.10 mL) and compound I (TBA[A-α-PMoO 31 (py)3], TBA salt (TBA=tetra-n-butylammonium; 488 mg, 0.20 mmol) was added. After stirring this solution at room temperature for one hour, the resulting precipitate was collected by filtration using a membrane filter. This precipitate was dissolved in a mixed solvent of dichloromethane and acetonitrile, and 70% aqueous nitric acid solution (26 μL, 0.40 mmol) was added, after which the solution was vigorously stirred for 5 minutes. After that, diethyl ether (3 mL) was added and the solution was allowed to stand, yielding a single crystal of the V tetranuclear structure compound (160 mg, 32% yield).

[0059] Mass spectrometry (MS) of the obtained crystals, 31 P-NMR and 51 The results of V-NMR measurement, IR measurement and elemental analysis are as follows. Positive-ion MS (CSI, acetonitrile): Measured m / z = 2724.5 (calculated m / z = 2724.2; [TBA4PV4Mo9O 41 ] + ). 31 P-NMR (202.47 MHz, acetonitrile-d3): δ = -3.75 ppm. 51 V-NMR (131.6MHz, acetonitrile-d3): δ = -593.8, -587.8, -593.3ppm (integral ratio 1:2:1). IR (KBr pellets) 1635, 1483, 1384, 1152, 1073, 1048, 1007, 952, 877, 802, 650, 595, 511, 381, 373 cm -1 . Elemental analysis: TBA3PV4Mo9O 41 Calculated values ​​(%): P, 1.25; Mo, 34.79; V, 8.21. Measured values: P, 1.26; Mo, 38.21; V, 7.97. The results of X-ray structural analysis of the obtained crystals are shown in Table 3.

[0060] [Table 3]

[0061] From the above-mentioned examples, the synthesis of a novel Mn hexanuclear structure compound and a novel V tetranuclear structure compound was confirmed. In the above-mentioned examples, a polyoxometalate compound having a structure in which a polyatom (Mo) is coordinated to a heteroatom (P) via an oxygen atom and pyridine is introduced at the defective structural site is reacted with manganese acetylacetonate or vanadyl acetylacetonate. However, if a polyoxometalate compound has a structure in which at least one polyatom selected from the group consisting of Mo, V, Nb, and Ta is coordinated to a heteroatom via an oxygen atom and an unshared electron pair-containing compound is introduced at the defective structural site, it is considered that the polyoxometalate compound having the specific polyatom described above will be sufficiently stabilized by the introduction of the unshared electron pair-containing compound, and therefore it is certain that a wide variety of novel polynuclear metal compounds can be obtained by reacting this with a compound containing a metal atom different from the heteroatom and polyatom.

Claims

1. A method for producing a polynuclear metal compound having a structure in which a metal atom other than a hetero atom and a poly atom is introduced into a defective structural site of a polyoxometalate compound, comprising the steps of: The production method includes a step of reacting a polyoxometalate compound (A) having a structure in which a polyatom, which is Mo, is coordinated to a heteroatom via an oxygen atom and an unshared electron pair-containing compound is introduced into a defective structural site with a compound (B) containing a metal atom different from the heteroatom and the polyatom, the atom having an unshared electron pair contained in the unshared electron pair-containing compound is at least one atom selected from the group consisting of a nitrogen atom, an oxygen atom, a phosphorus atom, and a sulfur atom; The metal atom different from the heteroatom and the polyatom is at least one selected from the group consisting of a 3d transition metal atom, a 4d transition metal atom, a 5d transition metal atom, and a rare earth element.

2. A method for producing a polynuclear metal compound comprising the steps of:

2. The heteroatom is at least one selected from the group consisting of Si, P, Al, S, Ge, As, and Se. The method for producing a polynuclear metal compound according to claim 1 .

3. The compound (B) having a metal atom different from the heteroatom and the polyatom contains at least one group selected from the group consisting of a carboxylate group, a trifluoromethanesulfonate group, and an acetylacetonate group. The method for producing a polynuclear metal compound according to claim 1 or 2.

4. A polynuclear metal compound having a structure in which a metal atom other than a hetero atom and a poly atom is introduced into a defective structural site of a polyoxometalate compound, The polynuclear metal compound has a structure in which a polyatom, which is Mo, is coordinated to a heteroatom via an oxygen atom, The metal atom different from the heteroatom and the polyatom is at least one selected from the group consisting of a 3d transition metal atom, a 4d transition metal atom, a 5d transition metal atom, and a rare earth element. A polynuclear metal compound comprising:

Images