MANUFACTURE METHOD FOR METAL-SUPPORTED CATALYST

BACKGROUND OF THE INVENTION

1. Field of the Invention [OOOJJ The invention relates to a manufacture method for a metal-supported catalyst in which a catalyst metal is supported on a catalyst support.

2. Description of the Related Art

[0002] A size-controlled metal cluster is different from a bulk metal in chemical characteristics, such as catalytic activity and the like, and physical characteristics, such as magnetism and the like.

[0003] Ih order to efficiently utilize the peculiar characteristics of the metal cluster, a method for easily synthesizing a size-controlled cluster in large amount is needed, A known method for obtaining such a cluster is a method in which (i) clusters of various sizes are produced by causing a metal target to evaporate in vacuum, and (ϋ) the thus-obtained clusters are separated according to cluster sizes through the use of the principle of the mass spectrum. However, this method is not able to easily synthesize a cluster in large amount.

[0004] The peculiar characteristics of the cluster is disclosed in ₇ for example, "Adsorption and Reaction of Methanol Molecule on Nickel Cluster Ions, Ni _n ⁺ (n=3-H)",

M. Ichihashi, T. Hanmura, R. T. Yadav and T. Kαndow, J- Phys. Chem. A, 104, 11885

(2000) (Related Art 1). This document discloses that the reactivity between methane molecules and platinum catalyst in the gas phase is greatly affected by the platinum, cluster size, and that there exists a particular platinum cluster size that is optimal for the reaction, for example, as shown in FIG 1.

[0005] Examples of utilization of the catalytic performance of a noble metal include purification of exhaust gas discharged from an internal combustion engine, such as an automotive engine or the like, At the time of the purification of exhaust gas, exhaust gas components, such as carbon monoxide (CO), hydrocarbon (HC), nitrogen oxide (NO^j),

etc., are converted into carbon dioxide, nitrogen and oxygen by catalyst components whose main component is a noble metal such as platinum (Pt), rhodium (Rh), palladium (Pd), iridium (Ir), etc. Generally, the catalyst component that is a noble metal is supported on a support made of an oxide, such as alumina or the like, in order to enlarge the contact area for exhaust gas and the catalyst component.

[0006] In order to support a noble metal on an oxide support, the oxide support is impregnated with a solution of a nitric acid salt of a noble metal or a noble metal complex having one noble metal atom so that the noble metal compound is dispersed on surfaces of the oxide support, and then the support impregnated with the solution is dried and fired. In this method, however, it is not easy to control the size and the number of atoms of the noble metal duster.

[0007] λVϊth regard Io such catalysts for exhaust gas purification, loo, the supporting of a noble metal in the form of clusters has been proposed in order to further improve the exhaust gas purification capability. For example, Japanese Patent Application Publication No. JP-A-11-285644 (Related Art 2) discloses a technology in which a catalyst metal is supported in the form of ultrafine particle directly on a support through the use of a metal cluster complex that has a carbonyl group as a ligand,

[0008] Furthermore, Japanese Patent Application Publication No. JF-A-2003-181288 (Related Art 3) discloses a technology in which a noble metal catalyst having a controlled cluster size is manufactured by introducing a noble metal into pores of a hollow carbon material, such as carbon nanotube or the like, and fixing the carbon material with the noble metal introduced therein to an oxide support, and then firing it.

[0009] Still further, Japanese Patent Application Publication No. JP-A-9-253490 (Related Art 4) discloses a technology in which a metal cluster made up of an alloy of rhodium and platinum dissolved in the solid state is obtained by adding a reductant to a solution containing rhodium ions and platinum ions.

SUMMARY OFTHE INVENTION [0010] The invention provides a manufacture method for a metal-supported catalyst in

which a size-controlled cluster catalyst is supported with a high degree of dispersion.

[00ϊ1] A manufacture method for a metal-supported catalyst in accordance with an aspect of the invention includes: binding a compound having a coordinatable functional group onto a catalyst support; impregnating the catalyst support to which the compound having the coordinatable functional group is bound, with a solution that contains a metal complex in which a ligand is coordinated to one catalyst metal atom or a plurality of catalyst metal atoms of the same kind, and substituting at least partially the Kgaad coordinated in the metal complex with the coordinatable functional group of the compound; and drying and firing the catalyst support impregnated with the solution. [0012] It is to be noted herein that in the invention, the "binding" between a catalyst support and a ^' compound having a coordinatable functional group includes not only a definite chemical bond, but also so-called adsorption due to the affinity between a catalyst support and a compound having a coordinatable functional group.

[0013] According to the foregoing aspect, since the ligand coordinated in the metal complex is at least partially substituted with the ligand of the compound bound to the catalyst support, the metal complex is fixed onto the catalyst support, so that movement of the metal complex on the catalyst surfaces is restrained. Thus, it is possible to obtain a supported-type catalyst in which a catalyst metal, particularly a catalyst metal in the form of clusters, is supported with high degree of dispersion- [0014] In the foregoing aspect, the metal complex may be a polynuclear complex.

[0015] According to this aspect, a cluster having the same number of metal atoms as • contained in the metal complex can be obtained.

[0016] In the foregoing aspect, the compound bound to the catalyst support may have a plurality of coordinatable functional groups. [0017] According to this aspect, since the compound on the support surfaces has a plurality of metal complexes, a cluster having a number of metal atoms that is equal to the total number of metal atoms contained in these metal complexes can be obtained.

[001$] In the foregoing aspect, the coordinatable functional group of the compound aud a functional group of the ligand which is coordinated to the catalyst metal may be each

independently selected from the group consisting of:

-COCT, -CB}R ² -Q; -NR ¹ -, -NR ^X R ² , -CR^N-R ² , -CO-R*, -PR ¹ R ² , -P(=;O)R ^X R ² , -P(OR*)(OR ² ) ₃ -SR ¹ , and -CRV-S ^" (R ¹ and R ² each independently are hydrogen or a monovalent organic group). [0019] In the foregoing aspect, the functional group of the compound and the functional group of the ligaπd which is coordinated to the catalyst metal may be the same.

[0020] According to this aspect, the ligaπd coordinated in, the metal complex can be at least partially substituted with the coordinatable functional group of the compound bound to the catalyst support, in a state where the metal complex is relatively stable. [002X] In the foregoing aspect, the catalyst support may be a metal oxide catalyst support.

[0022] According to this aspect, the compound having a coordinatable functional group can be bound to the metal oxide catalyst support by reacting the compound with a hydroxy! group of the metal oxide catalyst support.

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The foregoing and/or further objects, features and advantages αf the invention will become more apparent from the following description of preferred embodiment with, reference to the accompanying drawings, in which like numerals are used to represent like elements and wherein;

FIG. 1 is a graph showing a relationship between the cluster size of Pt and the reactivity extracted from Related Art 1;

FIG 2 is a schematic diagram of a scheme of Example 1; FIG. 3 is a schematic diagram of a scheme of Example 2; FIG 4 is a schematic diagram of the scheme of Example 2;

FIG. 5 shows a TEM photograph in which the appearance of Pt on MgO prepared by a method of Example 2 was observed; and

FϊG. 6 is a schematic diagram of a scheme of Example 4.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0024] Iu the following description, the present invention will be described in more detail in terms of exemplary embodiments.

[0025] A metal-supported catalyst in accordance with an embodiment is manufactured by the following procedure: (a) binding a compound having a coordinaiable functional group onto a catalyst support; (b) impregnating the catalyst support to which the compound having the coordiαatable functional group is bound, with a solution, that contains a metal complex in which a ligand is coordinated to one catalyst metal atom or a plurality of catalyst metal atoms of the same kind, and substituting at least partially the ligand coordinated in the metal complex with the coordinatable functional group of the compound; and (c) drying and firing the catalyst support impregnated with the solution. [0026] (Metal That Becomes a Nucleus of a Metal Complex)

The catalyst metal that becomes a nucleus of a metal complex used in this embodiment may be an arbitrary metal that can be used as a catalyst. Therefore, this catalyst metal may be either a main group metal or a transition metal. This catalyst metal may be particularly a transition metal, and more particularly fourth to eleventh group transition metals, for example, a metal selected from the group consisting of lilanium, vanadium, chrome, manganese, iron, cobalt, nickel, zirconium, niobium, molybdenum, technetium, ruthenium, rhodium, palladium, silver, hafnium, tantalum, tungsten, rhenium, osmium, iridium, platinum, and gold. Examples of commonly used catalyst metals include iron group elements (iron, cobalt, nickel), copper, platinum group elements (ruthenium, rhodium, palladium, osmium, iridium and platinum);, gold, and silver.

[0027] (Metal Complex)

The metal complex used in the manufacture method for a metal-supported catalyst in accordance with the embodiment may be an arbitrary metal complex in which a ligand is coordinated Io one catalyst metal atom or a plurality of catalyst metal atoms of the same kind. That is, the metal complex may be a polynuclear complex, for example, a complex that has 2 to 10 metal atoms, particularly 2 to 5 metal atoms,

[0028] This metal complex may be an arbitrary metal complex. Concrete examples

of the metal complex include [PU(CHsCOO)S], [Pt(acac)a] ("acac" is an acetyl acetonato ligand), [Pt(CH ₃ CH ₂ NHs) ₄ ]Cl ₂ , [Rh ₂ (C ₆ H ₅ COO) ₄ ], [Rh ₂ (CH ₃ COO) ₄ ],

[Rh ₂ (OOCCeH ₄ COO) ₂ ], [Pd(acac) ₂ ], [Ni(acac) ₂ ], [Cu(CnH ₂₃ COO) ₂ J ₂ ,

[CU ₂ (OOCC ₆ H ₄ COO) ₂ ], [CU ₂ (OOCQJH ₄ CH ₃ H [MO ₂ (OOCC _1S H ₄ COO) ₂ ], [Mo ₂ (CH ₃ COO) ₄ ], and [NOa-C ₄ Hp) ₄ ] [Fe ^π Fe ^ffl (ox) ₃ ] ("ox" is a» oxalic acid iigand), [0029] (Ljgand of Metal Complex)

The ligand of the metal complex may be arbitrarily selected, taking into consideration the stability of the metal complex, the ease of substitution of the ligand with the compound bouad onto the catalyst support- etc The ligand of the metal complex may be a unϊdeutate Ugand, or a polydetitate ligand such as a chelate ligand.

[0030] This ligand of the metal complex may be a hydrogen group to which one functional group selected from the group consisting of functional groups mentioned below is bound, or an organic group to which one or more functional groups selected from the group consisting of functional groups mentioned below are bound, particularly an organic group to which one functional group or two or more same functional groups selected fyom the group consisting of: -COO ^" (carboxy group), -CR^-O ^* (alkoxy group), -NR. ^1" (amide group), -NR ¹ R ² (amine group), -CR ^l =N-R ² (ϊmine group), -CO-R ¹ (caxbonyl group), -PR ¹ R ² (phosphuie group), -P^O)R ¹ R ² (phosphine oxide group), -F(OR ¹ XOR ² ) (phosphite group), -S(=O) ₂ R ¹ (sulfone group), -S ⁺ (O^)R ¹ (sulfoxide group), -SR ¹ (sulfide group), and -CR ¹ K ² ^S ^" (thiolato group); and particularly -COO ^' (carboxy group), -CR ¹ R ² VO ^" (alkoxy group), -NR ^1" (amide group), and -NR ¹ R ² (amine group) (R ¹ and R ² each independently are hydrogen or a monovalent organic group).

[0031] The organic group to which a functional group is bound may be a substituted or non-substituted hydrocarbon group, particularly a substituted or non-substituted hydrocarbon group of C ₁ to C ₃₀ (i.e., whose carbon atom number is 1 to 30; this will be applied in the following description as well), that may have a ^' hetroatom, an ether bond or an ester bond. Ih particular, this organic group may be an alkyl group, aα alkenyl group, an alkynyl group, an aryl group, an aralkyl group or a monovalent alicyclic group of C ₁ to C ₃₀ , particularly C ₁ to Qo. More particularly, this organic group may be an alkyl group,

an alkenyl group, an alkynyl group of Ci to Q, particularly C _x to Q.

[0032] R ¹ and R* may each independently be hydrogen, or a substituted or non-substituted hydrocarbon, gtoup, particularly a substituted or non-substituted hydrocarbon group of Ci to C ₃₀ , that may have a hetroatom, an ether bond or an ester bond. ' Particularly, R ¹ and R ² may be hydrogen, or an alkyl group, an alkenyl group, an alkynyl group, an aryl group, an aralkyl group or a monovalent alicyclic group of Ci to C ₃ o, particularly Ci to Qo. More particularly, R ¹ and R ² may be hydrogen, or an alkyl group, an alkenyl group or an alkynyl group of C ₁ to C ₅ , particularly Cj to C ₃ .

[0033] Examples of the ligand of the metal complex include a carboxylic acid ligand (R-COO ^" ), an, alkoxy ligand (R-CR ¹ R ² O ^" ), an amide ligand (R-NR ^1" ), an amine ligand

(R-NR ¹ R ² ), an imine ligand (R-CR^N-R ² ), a carbonyl ligand (R-CO-R ¹ ), a phosjphine ligand (R-PR ¹ R ² ), a phosphine oxide Ugand (R-P(^O)R ¹ R ² ), a phosphite ligand

CR-P(OR ¹ XOR ² )), a sulfcme ligand (R-S(=O) ₂ R ^X ), a sulfoxide ligand (R-S^-O-)R ¹ ), a sulfide ligand (R-SR ¹ ), and a thiolato ligand (R-CR^-S ^" ) (R is hydrogen or an organic group, and R ¹ and R ² are as mentioned above).

[0034] Concrete examples of the carboxylic acid ligand include a formic acid (formate) ligand, an acetic acid (acetato) ligand, a propionic acid (propionate) ligand, and an ethylenediaminetetraacetic acid ligand.

[0035] Concrete examples of the alkoxy ligand include a methanol (methoxy) ligand, an ethanol (ethoxy) ligand, a propanαl (propoxy) ligand, a butanol (butoxy) ligand, a pentanol (pentoxy) ligand, a dodecanol (dodecyioxy) ligand, and a phenol (paenoxy) ligaαd.

[0036} Concrete examples of the amide ligand include a dimethyl amide ligand, a diethyl amide Ugand, a di-n-propyl amide ligand, a dϋsopropyl amide ligand, a di-n-butyl amide ligand, a di-t-butyl amide ligand, and a nicotinamide.

[0037] Concrete examples of the amine ligand include methyl amine, ethyl amine, methyl ethyl amine, trimethyl amine, triethyl amine, ethylene diamine, trϊbutyl amine, hcxamethylene diamine, aniline, propylene diamine, trimethylene diamine, diethylene triarnine, Methylene tetraamine, tris(2-aminoethyl)aπnne, ethanol amine, Methanol amine,

dielhanol amine, piperidine, Methylene tetraniine, and Methylene diamine.

[0038] Concrete examples of the imine ligand include diimine, ethyleneimine, ethyleneimine, propyleneimine, hexamethyieneimine, benzophenoneimine, methyl ethyl ketone imine, pyridine, pyrazole, imidazole, and benzoimϊdazole. [0039] Concrete examples of the carbonyl ligand include carbon monoxide, acetone, benzophenone, acetyl acetone, acenaphthoquinone, hexafluoroacetyl acetone, benzoyl acetone, trifluoioacetyl acetone, and dibenzoyl methane,

[0040] Concrete examples of the phosphine ligand include phosphorus hydride, methyl phosphine, dimethyl phosphine, trimethyl phosphine, and diphosphine. [0041] Concrete examples of the phosphine oxide ligand include tribtityl phosphine oxide, tripheπyl phosphine oxide, and tri-n-octyl pbosphine oxide.

[0042] Concrete examples of the phosphite ligand include triphenyl phosphite, trϊtolyl phosphite, tribυlyl phosphite, and triethyl phosphite,

[0043] Concrete examples of the sulfone ligand include hydrogen sulfide, dimethyl sulfone, and dibutyl sulfone.

[0044] Concrete examples of the sulfoxide ligand include a dimethyl sulfoxide ligand, and a dibutyl sulfoxide ligand.

[004S] Concrete examples of the sulfide ligand include ethyl sulfide, butyl sulfide, etc. [0046] Concrete examples of the thiolato ligand include a methanethiolato ligand, and a benzeπethiolato ligand.

[0047] (Compound Bound onto Catalyst Support)

The compound bound onto the catalyst support may be an arbitrary compound that has a functional group capable of substituting a ligand of the metal complex.

[0048] This compound may have a functional group for binding the compound to the .. catalyst support. Examples of the functional group of this compound include functional groups mentioned above in conjunction with the ligand of the metal complex.

Particularly, in the case where the catalyst support is a metal oxide support, the functional group capable of binding may particulaxly be a hydroxyl group and a carboxy group. The

^• hydroxyl group and the carboxy group arc capable of reacting with a hydroxyl group on a

surface of the metal oxide support, particularly undergoing dehydration condensation therewith, so as Io bind the compound having a coordiπatable functional group to the metal oxide support. The functional group for bidding the compound to the catalyst support may be the same functional group as the coordinatable functional group of the compound. In that case, the compound has a plurality of same functional groups, and one or more of these same functional groups function as functional groups for binding the compound to the catalyst support, and the other functional group or groups function as coordinatable functional groups for substituting the ligand of the metal complex.

[0049] Examples of the coordinatable functional group of the compound include functional groups mentioned above in conjunction with the ligand of the metal complex. The coordinatable functional group is .selected so as to be able to substitute the ligand coordinated in the metal complex to be used a raw material. Therefore, generally, the functional group capable of substituting the ligand of the metal complex is a functional group that has stronger coordinating power than the ligand coordinated in the metal complex to be used as a raw material, particularly a functional group that has stronger coordinating power than the ligand coordinated in the metal complex to be used as a raw material and that has the same functional group as the ligand does. In order to accelerate the substitution of the ligand of the metal complex with the coordinatable functional group of the compound, the compound may be used in relatively large amount. [0050] Ia the case where the compound bound onto the catalyst support has a plurality of coordinatable functional groups, the ligands may be disposed with a certain space left therebetween in order to avoid the sterfc hindrance between the metal complexes. However, if the space is excessively large, there arises a possibility of making it difficult to obtain a single duster from the plurality of complexes coordinated to the plurality of functional groups.

[0051] The compound bound onto the catalyst support may be a compound that has two or more of any one species of the functional groups mentioned above in conjunction with the ligand of the rαetal complex, for example, a plurality of carboxy groups. In this case, one or more of these functional groups may be used for the binding with the catalyst

support, and the other functional group or groups may be used as coordinatable functional groups, as stated above. Therefore, for example, the compound bound onto the catalyst support may be a dicarboxylic acid, a tricarboxylic acid or a tetracarboxylic acjd of C ₂ to C ₃₀ , particularly Oi to Qo, or a benzenedicarboxylic acid, a benzenetricarboxylic acid, or a benzenetetracarboxytøc acid.

[0052] More concrete examples of the dicaxboxylic acid include oxalic acid, malonic acid, succinic acid, glutarjc acid, adipic add, pimelic acid, suberic acid, azelaic acid, sebacic acid, phthalic acid, isophthalic acid, and ' terephthalic acid. More concrete examples of the tricarboxylic acid include triraesic acϊd (1,3-5-benzenetricarboxyKc acid). More concrete examples of the tetracarboxylic acid include 1,2,3,5-benzenetetracarboxylic acid.

[0053] In the case where a compound that has a plurality of cooxdinatable functional groups when bound to the catalyst support is used, a number of metal complexes that is greater than the number of the functional groups are needed in order to coordinate the metal complexes to all the functional groups. Therefore,, for example, in the case where trirnesϊc acid (1,3,5-benzenetricarboxyiic acid) is used as this compound, 2 moi of the metal complex is needed with respect to 1 mol of trimesic acid in order to coordinate two metal complexes to each molecule of trimesic acid on the assumption that one of the carboxy groups of trimesic acid is bound to the catalyst support. [0054] (Drying and Firing Condition)

The drying and firing of the catalyst support impregnated with a metal complex-containing solution may be performed in a condition of a temperature and a time that are sufficient to obtain a metal or metal oxide cluster. For example, the drying is performed at a temperature of 120 to 25O ⁰ C for 1 to 2 hours, and then the firing is performed at a temperature of 400 to 600 ⁰ C for 1 to 3 hours. The solvent of the solution to be used in this process may be an arbitrary solvent that is capable of stably maintaining a multiple-metal complex-containing compound, for example, an aqueous solvent, or an organic solvent such as dichloroethane or the like. [0055] (Catalyst Support)

The catalyst support to be used in the manufacture method for a raetal-supported catalyst in accordance with the embodiment may be a metal oxide support, for example, a metal oxide support selected from the group consisting of alumina, ceria, zirconia, silica, titaαia, and their combinations. The catalyst support may be a porous support. [0056] The invention will be described hereinafter with reference to examples- The examples shown below are merely for illustration of the invention, and do not limit the invention in any manner. [0057] (Example 1) FIG. 2 shows a scheme of Example 1. [0058] (Synthesis of [Pt ₄ (CH ₃ COO) _S ])

The synthesis of the compound was performed using a procedure described in "Jikkcπ

Kagaku Kouza (Experimental Chemistry Course)", 4th ed., Vol. 17, p. 452, Maruzen

(1991), That is, the synthesis was performed as follows. 5 g of K ₂ PtCL* was dissolved in 20 ml of warm water, and 150 ml of glacial acetic acid was added to the solution. Then, 8 g of silver acetate was added regardless of the presence/absence of precipitation of

KsPtCU. This slurry-like material was refluxed for 3 to 4 hours while being stirred by a stirrer. After the material was let to cool, black precipitation was filtered out. Through the use of a rotary evaporator, acetic acid was removed by concentrating brown precipitation as much as. possible. This concentrate was combined with 50 ml of acetonitrile, and the mixture was left standing. The produced precipitation was filtered out, and the filtrate was concentrated again. Substantially the same operation was performed on the concentrate three times. The final concentrate was combined with 20 ml of dichloromethane, and was subjected to adsorption on a silica gel column. The elution was performed with dichloromethane-acetonitrile (5:1), and a red extract was collected and concentrated to obtain a crystal.

[0059] (Pretreatment of a Support with Dicarboxylic Acid)

10 g of magnesium oxide (MgO) was dispersed in 100 g of ethanol. While this MgO dispersed solution was being stirred, a solution obtained by dissolving 100 mg of succinic acid (HOOC-CH ₂ CH ₂ -COOH), that is, a dicarboxylic acid, in 50 g of ethanol was added to

the dispersed solution. The mixture was stirred for 30 mm so as to allow succinic acid to adsorb to MgO. After that, MgO and the solution was separated by centrifugal separation. The thus-obtained MgO was washed and separated through the use of 100 g of ethanol three times to remove the succinic acid that did not react with MgO. The thus-obtained MgO was air-dried to obtain a succinic acid-treated MgO. [0060] (Supporting of [Pt ₄ (CH ₃ COO)s])

10 g of the succinic acid-treated MgO obtained as described above was dispersed in 200 g of acetone. While the MgO dispersed solution was being stirred, a solution obtained by dissolving 16.1 mg of [Pt ₄ (CHsCOO) _S ] in 100 g of acetone was added. Then, the mixture was stirred for 30 miπ. When the stirring was stopped, reddish MgO precipitated, and the supernatant liquid became transparent (i.e.. [P.4(CH3COO)g] adsorbed to the succinic acid-treated MgO).

[0061] (Comparative Example 1)

[Pt ₄ (CH ₃ COO)s] was supported on the MgO support in substantially the same manner as in Example 1, except that the pretreatment of the support with dicarboxylic acid was not performed. Specifically, 10 g of the MgO not subjected to the dicarboxylic acid prefcreatment of the support was dispersed in 200 g of acetone- While the MgO dispersed solution was being stirred, a solution obtained by dissolving 16.1 mg of [Pt ₄ (CH ₃ COO)g] in

100 g of acetone was added. Then, the mixture was stirred for 30 mitt. When the stirring was stopped, MgO precipitated, and the supernatant liquid became pale red (Le.,

[Pt ₄ (CH ₃ COO)B] did not adsorb to MgO).

. [0062] (Example 2) (Synthesis of [Pt ₄ (CH ₃ COO) ₇ {θ ₂ C(CH ₂ ) ₃ CH=CH(CH ₂ ) ₃ Cθ ₂ }(CH ₃ COO) ₇ Pt ₄ ])

FIGS. 3 and 4 show a scheme of the synthesis of the compound, [0063] Concretely, the compound was synthesized as follows.

(19,4 μL _> 18.6 mg) was added to a CH ₂ Cl ₂ solution (10 mL) of [Pt ₄ (CH ₃ COO) ₈ ] (0.204 g,

_, 0.163 mmol) obtained as in Example 1. This changed the color of the solution from

' orange to red-orange. After the solution was stirred at room temperature for 2 hours, the solvent was removed by evaporation under reduced pressure, and the remaining substance

Xo

.was washed with- diethyl ether (8 ml) ' twice: As a result; an- orange solid of [Pt ₄ (CH ₃ COO) ₇ (O ₂ C(CHz) ₃ CH-CH ₂ )] was .obtained.

. [0064] [Pt ₄ (CH ₃ COO) ₇ (O ₂ C(CH ₂ )SCH=CH ₂ )] (362 tag, 0.277 xnmol) synthesized as ' described above and a first-generation Grubb ^' s catalyst (6.7 mg, 8.1 μmσl, 2& mol%) ^' wefe^ 5 placed in, an argon-substiluted .Schlenk device, and were dissolved in CH ₂ Cl ₂ . (30 jnL). ■ ^• A- cooiing pipe was attached to the Schlenk device, and a heated reflux was performed in an oil bath. After the solution was refluxed for 60 hours, the solvent was- removed by . ^' evaporation under reduced pressure, and the remaining substance was dissolved in CH ₂ CIj.: After that, filtration via a glass filter was performed. The filtrate was concentrated under 10 reduced pressure to obtain a solid. The solid -was washed with diethyl ether (XO mL) three times to obtaia an • orange solid > of

[P _-4 (CH ₃ COO) ₇ (O ₂ C(CHz) ₃ CH=CH(CHz) ₃ CO ₂ )(CH ₃ COO) ₇ Pt ₁ ] as an E/Ztype mixture. [0065] Spectral data of [P _-4 (CH3COO)7{O ₂ C(CH ₂ )3CH-CH2)] is shown below. [0066] ¹ H NMR (300MHz, CDO ₃₇ 30SK) δ: 1.89 (tt, ³ JHH=7.5, 7.5 Hz ₅ 2H, 15 O ₂ CCH ₂ CH ₂ -), 1.99 (s, 3H, ^ ₂ CCH ₃ ), 2.00 (s, 3H, ^Q ₂ CCH ₃ ), 2.01 (s, 6H, ^ax O ₂ CCHi), 2.10 (q like, 2H, -CH ₂ CH=CH ₂ ), 2.44 (s, 6H, ^O ₂ CCH ₃ ), 2.45 (s, 3H, ⁶¹⁵ OiCCH ₃ ), 2.70 (t ^{" 3} JH _H =7.5 HZ, 2H ₅ O ₂ CCH ₂ CH ₂ -),, 496. (ddt^ ?JHH=10.4 HZ ₃ ^Z JHH=1-8 HZ/JHH=? HZ ₃ IH ₄₁ ,. -CH=C (H) ⁴ H) ₅ 5.01 (ddt; ³ Jπk=17.3 Hz, ² J» _H «1.S HZ, ^HH=? HZ, IH, -CH^C (H) ^ttans H), ^ 5.81 (ddt, ³ JHH=17.3, 10.4, 6,6 Hz, IH, -CH=CHa).

, 20 [0067] ¹³ C( ¹ H) NMR (75MHz, CDCl ₃ , 308K) δ: 21.2, 21.2 CO ₂ CCH ₃ ), 22.0, 22.0 , CO ₂ CCH ₃ ), 25.8 (O ₂ CCH ₂ CH ₂ -), 33.3 (-CH ₂ Ok=CH ₂ ), 35.5 (O2CCH2CH ₂ -), 115.0 (-CH=CH ₂ ), 137.9 (-CH=CH ₂ ), 187.5; 193.0, 193.1 (O ₂ CCH ₃ ), 189.9 (O ₂ CCH ₂ CH ₂ -). [0068] MS (ESI+, CH ₃ CN solution) m/z: 1347 ([M+sol.]-*)- [0069] IR (KBr disk, v/cnf ¹ ): 2931, 2855 (V _C -H) _> 1562, 1411 (vcoo-), 1039, 9-17

25 . (v-c-c). ^■

[0070] Spectral data of [Pt ₄ (CH ₃ COO) ₇ {O ₂ C(CH ₂ ) ₃ CH=CH(CH ₂ ) ₃ CO ₂ }(CH ₃ COO) ₇ Pt ₄ ] is shown below.

[0071J Major(E type): ¹ H NMR (300MHz, CDCl ₃ , 30S£) δ: 1.83 (like, J=7.7 Hz, 4H, O ₂ CCH ₂ CH ₂ -), 2.00 (s; .

6H, ^O ₂ CCH ₃ ), 2.01 (s, 18H, "O ₂ CCH ₃ ), 2.02-2:10 (in, 4H, -CH ₂ CH=CH-), 2.44 ^" (s, 18H, ^O ₂ CCH ₃ ), 2.67 (t, ³ J _H-H =7.2 Hz ₅ 4H ₇ O ₂ CCH ₂ CH ₂ -), 5.37-5.45 (m, 2H, -CH^),

[0072] ¹³ C NMR (75MHz, CPCl ₃ , 308K) θ: 21,I ₇ . (q, ¹ Jc _H =ISO^ Hz, ^O ₂ CCH ₃ ), 21.2a tø, ¹ Jc-H^lSLl Hz, " ³ O ₂ CCH ₃ ), 21.9 (q, ¹ J _C -n ⁱ =129.4. Hz ₁ ^O ₂ CCH ₃ ), 22.0 '(g, ^■ ^0^=129.4 Hz, " ¹ O ₂ CCH ₃ ), 26.4 (t, ^ _c . _H =127.3.Hz _I O ₂ CCH ₂ CH ₂ -), 32;0 (t, ¹ J _C- H=127.3 Hz ₁ -CH ₂ CH=CH-), 35.5 (t, ¹ 3 _C Ά=130.2 HZ, O ₂ CCH ₂ CH ₂ -), 130.1 (d, ^l Jc&=4A&J6 Hz, -CH=), 187.3, 187.4, 193.0 (O ₂ CCH ₃ ), 189.9 (O ₂ CCH ₂ CH ₂ -).

[0073] Minor(Z type): ^{■ 1 H NMR (300MHz, CDCl ₃ , 30SK) δ: 1.83 (like, J=7.7 Hz, 4H ₁ O ₂ CCH ₂ CH ₂ -), 2.00 (s, 6H ₅ ^O ₂ CCH ₃ ), 2.01 (s, 18H ₁ ^O ₂ CCH ₃ ), 2.02-2.10 (m, 4H, -CH ₂ CH=OH 2.44 (s, 18H, ^O ₂ CCH ₃ ), 2.69 (t, 3 J _H - _H ==7.2 HZ ₉ 4H ₁ 0 ₂ CCH ₂ CH ₂ -), 5.37-5.45 (m, 2H, -CH=).}

[0074] ¹³ C NMR (75MHz, CDCl ₃ , 308K) δ: 21.I ₇ (q, ¹ JaK=ISO^ Hz, ^O ₂ CCH ₃ ),

21.2 ₂ (q, ¹ Jc- _H =BLl Hz _} ^O ₂ CCHs) ₁ 21.9 (q, ¹ J _C-H =129.4 Hz, ⁶¹¹ O ₂ CCH ₃ ), 22.0 (q, ^l Jc- _H =129-4 Hz, " ¹ O ₂ CCH ₃ ), 26.5 (t, ¹ J _O . _H =127.3 Hz, O ₂ CCH ₂ CH ₂ -)- 26.7 (t, ^"127.S Hz ₅ -CH ₂ CH=CH-), 35.5 (t, ^=130.2 Hz ₃ O ₂ CCH ₂ CH ₂ -), 129.5 (d, ^l J _c . _H =l54.3 Hz ₃

-CH=), 1873, 187.4, 193:0 (O ₂ CCH ₃ ), 189.9 (O ₂ CCH ₂ CH ₂ -).

[007S] MS (ESI+, CH ₃ CN solution) ro/z: .2584 ([M] ⁺ )- ^'

[0076] (Preftreatment of the Support with DicaTboxylic: Acid)

A succinic acid-txeated MgO was obtained in substantially the same manner as in Example 1,

[0077] (Supporting of [Pt ₄ (CH ₃ COO) ₇ {0 ₂ C(CH ₂ ) ₃ CH=CH(CH ₂ ) ₃ Cθ ₂ >(CH ₃ COO) ₇ Pt,])

XO g of the succinic acid-treated MgO obtained as described above was dispersed in 200

. g of acetone. While this MgO dispersed solution was being stiired, a solution obtained by dissolving 16.6 mg of [Pt ₄ (CH ₃ COO) ₇ {O ₂ C(CH ₂ ) ₃ CH=CH(CH ₂ ) ₃ CO ₂ }(CH3COO)7Ptv,] in

100 g of acetone was added. Then, the mixture was stirred for. 30 min. When the stirring was stopped, slightly orangϊsh MgO precipitated, and the supernatant liquid became transparent (i.e., [Ft,(CH ₃ COO) ₇ {0 ₂ C(CH ₂ ) ₃ CH=CH(CH ₂ ) ₃ C0 ₂ }(CH3COO) ₇ PU]

^' adsorbed to the succinic acid-treated MgO) ₁ .

£0078} (Comparative Example 2)

[Pt4(CH3COO)7{O ₂ C(CH ₂ )3CH^CH(Cϊt2)3Cθ2}(CH3COO) ₇ PU] was supported on the

MgO support in, substantially the same manner as in Example 2, except that the pretreatment of the support with dicarboxylic acid was not performed. Specifically, 10 g of the MgO not subjected to the dicarboxylic acid pretreatment of the support was dispersed in 200 g of acetone. While the MgO dispersed solution was being stirred, a solution obtained by dissolving 16.1 mg of

[Pt ₄ (CH ₃ CO0) ₇ {0 ₂ C(CH ₂ ) ₃ CH=CH(CH _s ) ₃ CO ₂ }(CH ₃ C0O)7Pt4] in 100 g of acetone was added. Then, the mixture was stjxred for 30 min. When the stirring was stopped, MgO precipitated, and the supernatant liquid became pale red (Le.,

[Pt ₄ (CH ₃ COO) ₇ (O ₂ C(CHz) ₃ CH^CH(CH ₂ ) _S CO ₂ XCH ₃ COO) ₇ Pt ₄ ] did not adsorb to MgO).

[0079] (TEM Observation of Clusters)

The appearance of the Pt on the MgO prepared by the foregoing method was observed by TEM. Using an HD-2000 type electron microscope of Hitachi, STEM images were observed at an acceleration voltage of 200 kV. An STEM image of Example 2 is shown in FIG. 5. In, this image, Pt particles having a spot diameter of 0.9 nm estimated from the structure of S-platinum atom clusters can be seen, demonstrating that, by the foregoing technique, 8-ρlatinum atom clusters can be supported on an oxide support. That is, it has been demonstrated that the firing of a compound in which a plurality of metal complexes are bound via a ligand provides a cluster that has all the metal atoms contained in the compound.

[0080] (Example 3) (Synthesis of [Pt ₄ (CH ₃ COO) ₅ ])

Using substantially the same procedure as in Example 1, [Pt ₄ (CH ₃ COO)S] was obtained, [0081] (Pretreatment of the Support with Dicarboxylic Acid)

3 g pf γ-alumina (γ~Akθ ₃ ) was dispersed in 50 g of ethanol. While the 7-AkO ₃ dispersed solution was being stirred, a solution obtained by dissolving 67 mg of adipjc acid (HOOC-(CH ₂ VCOOH), that is. a dicarboxylic acid, in SO g of ethanol was added. Then, the mixture was stirred for 30 min to allow adϊpic acid to adsorb to Y-AI2O3, After that,

γ-A-2θ3 and the solution was separated by centrifugal separation. The thus-obtained γ-Al2θ ₃ was washed, and separated with 50 g of ethanol three times to remove the adipic acid that did not react with γ-Al ₂ θ ₃ . The thus-obtained Y-Al ₃ O ₃ was air-dried to obtain an adipic aeid-treated Y-Al ₂ O ₃ . [0082] (SuPPOrIiBg Of [Pt ₄ (CH ₃ COO) ₈ ])

3 g of the adipic acid-treated Y-AI ₂ O ₃ obtained as described above was dispersed in 50 g of acetone. While the Y-AIjO ₃ dispersed solution was being stirred, a solution obtained by dissolving 48.3 mg of [Pt _J (CH ₃ COO) ₈ ] in 50 g of acetone was added. Then, the mixture was stirred for 30 mm. When the stirring was stopped, slightly reddish Y-Al ₂ Oa precipitated, and the supernatant liquid became transparent (Le., [Pt ₄ (CHsCOO) ₅ ] adsorbed to the adipic acid-treated γ-AlxOa),

[0083] (Comparative Example 3)

[Pt ₄ (CH ₃ COO) _S ] was supported on the support in substantially the same manner as in Example 3, except that the pietreatπiεnl of the support with dϊcaiboxylic acid was not performed. Specifically, 3 g of the Y-AIaO ₃ not subjected to the dicarboxylic acid pretreatraent of the support was dispersed in 50 g of acetone. While the Y-Al ₂ Oa dispersed solution was being stirred, a solution obtained by dissolving 48.3 mg of

[Pt ₄ (CH ₃ COO) _S ] in 50 g of acetone was added. Then, the mixture was stirred for 30 min.

When the stirring was stopped, Y-AbO ₃ precipitated, and the supernatant liquid became orange (i.e., [Pt ₄ (CH ₃ COO) ₈ ] did not adsorb to Y-Al ₂ O ₃ ).

[0084] (Example 4)

FIG- 6 shows a scheme of Example 4,

[0085] (Synthesis of [Pt ₄ (CH ₃ COO)S])

Using substantially the same procedure as in Example 1, [Pt ₄ (CH ₃ COO) ₈ ] was obtained. [0086] (Pxetreatmcnt of the Support with Tricarboxylic Acid)

10 g of γ-alumina (Y-AI ₂ O ₃ ) was dispersed in 100 g of ethanol. While the γ-Al ₂ θ3 dispersed solution was being stirred, a solution obtained by dissolving 6.7 mg (32 μmol) of trimesic acid (l-3,5~benzenetricarboxylic acid) in 50 g of ethanol was added. Then, the mixture was stirred for 30 min. After that, ethanol was removed from the solution by

using a rotary evaporator. The remaining substance was dried by using a vacuum dryer to obtain a trimesic acid-treated γ-Al2θ3. [00871 (Supporting of [Pt ₄ (CHbCOO) ₈ ])

3 g of the trimesic acid-treated Y-AJ ₅ O ₃ obtained as described above was dispersed in 100 g of acetone. While the γ-A- ₂ 0 ₃ dispersed solution was being stirred, a solution obtained by dissolving 803 mg (64 μmol) of [Pt ₄ (CEl ₃ COO) ₈ ] in 100 g of acetone was added. Then, the mixture was stirred for 16 hours. When the stirring was stopped, pale orange 7-AI ₂ O ₃ precipitated, and the supernatant liquid became transparent (i.e., [Pt ₄ (CH ₃ COO) ₈ ] adsorbed to the trimesic acid-treated γ-Al ₂ O ₃ ). [0088] While the invention has been described with reference to exemplary embodiments thereof, it should be understood that the invention is not limited to the exemplary embodiments or constructions. To the contrary, the invention is intended to cover various modifications and equivalent arrangements. In addition, while the various elements of the exemplary embodiments are shown in various ^" combinations and configurations, which are exemplary, other combinations and configurations, including more, less or only a single element, are also within the spirit and scope of the invention.