JP2001192712A - Metallic hyperfine particle and producing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a material capable of securely and easily realizing the deposition of a metallic film. SOLUTION: In this method for producing metallic hyperfine particles, a quaternary ammonium salt type metallic complex compound expressed by the general formula of [R1 R2 R3 R4 N]x [My(A)z] [wherein R1 to R4 are the same or different hydrocarbon groups and may have a substitutional group; M is transition metal; A is an organic sulfur ligand; (x) is an integer higher than zero; (y) is an integer higher than zero; and (z) is an integer higher than zero) is used as the starting raw material, and, by the reducing elimination reaction of the organic sulfur ligand in the compound, the central metal is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to ultrafine metal particles and a method for producing the same.

[0002]

2. Description of the Related Art Metal paste is used for forming conductive films such as electronic circuits and electrodes. These conductive films are formed by applying a metal paste on a non-conductive substrate such as ceramics or glass and baking and curing the coating film. In recent years, with the diversification of electronic materials and increasing demand, the use of metal paste is also rapidly expanding. One of them is for forming a metal conductive film formed by kneading a metal powder and a resin component. Thick film pastes are known.

[0003]

However, the conventional thick film paste for forming a metal conductive film has the following problems.

[0004] First, since the particle size of the metal powder is as large as several microns, the firing temperature is inevitably high, and a predetermined conductive film can be formed unless firing at a high temperature of at least 500 to 600 ° C. Have difficulty. In addition, since the firing temperature is high, it is difficult to apply the method to a base material such as plastic having low heat resistance.

[0005] Second, since the particle size of the metal powder is large as described above, pinholes are easily generated in the formed conductive film. Therefore, in order to obtain a dense conductive film without pinholes, it is necessary to repeat a series of steps of applying a thick film paste and firing it.

Third, the above-mentioned thick film paste requires at least steps of preparation of metal powder, preparation of resin components and kneading of both, and the production process cannot be said to be efficient.

Accordingly, it is a main object of the present invention to provide a material capable of forming a metal film more reliably and easily.

[0008]

The inventor of the present invention has conducted intensive studies in order to solve the problems of the prior art.
It has been found that the above object can be achieved when a specific metal complex compound is used, and the present invention has been completed.

That is, the present invention relates to the following ultrafine metal particles and a method for producing the same.

[0010] 1. Formula [R ¹ R ² R ³ R ⁴ N] _x [M
_y (A) _z ] (provided that R ^{1 to} R ⁴ are the same or different hydrocarbon groups and may have a substituent, M is a transition metal, and A is an organic sulfur-based coordination. And x is an integer greater than 0, y is an integer greater than 0, and z is an integer greater than 0.) A quaternary ammonium salt type metal complex compound represented by the following formula: A method for producing ultrafine metal particles, comprising reducing a central metal from a reductive elimination reaction of a system ligand.

2. Formula [R ¹ R ² R ³ R ⁴ N] _x [M
_y (A) _z ] (provided that R ^{1 to} R ⁴ are the same or different hydrocarbon groups and may have a substituent, M is a transition metal, and A is an organic sulfur-based coordination. And x is an integer greater than 0, y is an integer greater than 0, and z is an integer greater than 0.) A quaternary ammonium salt type metal complex compound represented by the following formula: A method for producing fine particles.

3. 3. The production method according to the above item 1 or 2, wherein a disulfide is formed together with the ultrafine metal particles.

4. The organic sulfur-based ligand is a thiolate ligand (SR ') or a thioacetylene ligand (SC≡CR')
(In each case, R ′ is a hydrocarbon group which may have a substituent.)
4. The method according to claim 3.

5. M is Au, Pt, Cu, Ni or P
5. The method according to any one of the above items 1 to 4, wherein d is d.

6. The above-mentioned items 1 to 5, which include, as an organic component in the obtained ultrafine metal particles, a hydrocarbon group component derived from [R ¹ R ² R ³ R ⁴ N] which is a counter cation of the quaternary ammonium salt type metal complex compound. Item.

[7] 7. The production method according to any one of items 2 to 6, wherein the heat treatment is performed so that the content of the metal component in the obtained ultrafine metal particles is 80 to 95% by weight.

8. Ultrafine metal particles comprising a central portion and a protective layer around the central portion, wherein the central portion comprises a metal component and the protective layer comprises an organic component.

9. 8. The ultrafine metal particles according to item 7, wherein the content of the metal component is 80% by weight or more. 10. 10. A material for forming a metal film, comprising the ultrafine metal particles according to item 8 or 9.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION The production method of the present invention has the general formula [R
^{1 R 2 R 3 R 4 N} ] x [M y (A) z] ( ^{where, R} 1 ~
R ⁴ is the same or different hydrocarbon group which may have a substituent, M is a transition metal, A is an organic sulfur-based ligand, x is an integer greater than 0, y is An integer greater than 0 and z represents an integer greater than 0. 4)
Using a quaternary ammonium salt type metal complex compound as a starting material, a central metal is reduced by a reductive elimination reaction of an organic sulfur-based ligand of the compound.

The quaternary ammonium salt type metal complex compound which is a starting material (hereinafter also referred to as a “precursor”) of the production method of the present invention has a general formula [R ¹ R ² R ³ R ⁴ N] _x [M _y ( A)
_z ]. If it has this general formula,
A product obtained by a known production method or a commercially available product can also be used. For example, when the above compound is represented by the general formula [R ₄ N] [Au
(SR ′) ₂ ] (R represents an alkyl group and R ′ represents an alkyl group. The same applies to 1) and 2) below. In the case of producing the quaternary ammonium salt type metal complex compound represented by the formula (1), it can be produced by the following steps 1) and 2) (reaction in a solvent).

1) HAuCl ₄ + R ₄ NCl → [R
₄ N] [AuCl ₄ ] + HCl 2) [R ₄ N] [AuCl ₄ ] + 4R′SNa → [R ₄
N] [Au (SR ') ₂ ] + R'S-SR' + 4NaC
l That is, a quaternary ammonium salt having a hydrocarbon group is reacted with a solution of a metal salt such as chloroauric acid, and the obtained product is reacted with a thiol compound in the presence of sodium methylate to give a predetermined quaternary compound. An ammonium salt type metal complex compound can be obtained. Therefore, in this case, 4
R ^{1 to} R ⁴ in the quaternary ammonium salt type metal complex compound
Can be determined by appropriately selecting the above quaternary ammonium salt. The ligand coordinated to the central metal can be determined depending on the type of the thiol compound. The solvent may be appropriately selected from known solvents according to the type of raw materials used and the like.

In the present invention, R ^{1 to} R ⁴ of the quaternary ammonium salt type metal complex compound may be the same or different hydrocarbon groups which may have a substituent.
The hydrocarbon group is not particularly limited, but is preferably an alkyl group having 1 to 20 carbon atoms which may have a substituent. Specifically, [R ¹ R ² R ³
[C ₁₂ H ₂₅ (CH ₃ ) ₃ N] as the [R ⁴ N] part,
[C ₁₄ H ₂₉ (CH ₃ ) ₃ N], [(C ₁₈ H ₃₇ )
Those having a linear alkyl group such as ₂ (CH ₃ ) ₂ N] and [C ₆ H ₁₃ (CH ₃ ) ₃ N] are exemplified.

When the hydrocarbon group has a substituent, the type of the substituent is not limited. For example, methyl group, ethyl group, OH group, nitro group, halogen group (Cl, Br
Etc.), methoxy group, ethoxy group and the like.

M is a transition metal and constitutes the central metal of the quaternary ammonium salt type metal complex compound. As the transition metal, for example, Au, Pt, Cu, Ni, Pd,
Co, Fe, Ti, Cr, Mn, Zr, and the like.
In the present invention, Au, Pt, Cu, Ni or Pd is particularly preferable.

A represents an organic sulfur-based ligand. If it is a ligand containing a sulfur atom, its chemical structure is not particularly limited,
In addition, any of a monodentate ligand, a bidentate ligand and the like may be used.

In particular, the organosulfur ligand of the present invention includes a thiolate ligand (SR ') or a thioacetylene ligand (SC≡CR') (in each case, R 'is a hydrocarbon group). And may have a substituent.). R 'is preferably an alkyl group having 1 to 20 carbon atoms, which may have a substituent. When it has a substituent, the type of the substituent is not limited, and the same as described above can be applied. The organic sulfur-based ligand may be any one of them, and may be appropriately selected depending on the type of the central metal and the like.

As the thiolate ligand, those represented by C _n H _{2n + 1} (n = 1 to 20) as the R ′ part are preferable. For example, C ₁₂ H ₂₅ , C ₆ H ₁₃ and C ₁₃ H ₃₇
And the like. As the R ′ part of the thioacetylene ligand, for example, C _n H _{2n + 1} (n = 1 to
8) are exemplified.

The substituted thioacetylene ligand is
C≡CR ′ as propyne, 2-propyn-1-ol, 1-butyn-3-ol, 3-methyl-1-butyn-3-ol, 3,3-dimethyl-1-butyne, 1-pentyne, 1-pentyn-3-ol, 4-pentin-1
-Ol, 4-pentyn-2-ol, 4-methyl-1
-Pentin, 3-methyl-1-pentyn-3-ol,
5-hexyn-1-ol, 5-methyl-1-hexyn-3-ol, 3,5-dimethyl-1-hexyn-3-
All, 1-heptin, 1-heptin-3-ol, 5
-Heptin-3-ol, 3,6-dimethyl-1-heptin-3-ol, 3,6-dimethyl-1-heptin-
Examples include 3-ol, 1-octin, 1-octin-3-ol, and the like.

Further, for example, a thioacetylene ligand containing a cyclic hydrocarbon having a hydroxyl group can also be applied. Such a ligand SC @ CR 'has 1-ethynyl-1-cyclopropanol, 1-ethynyl-1-cyclobutanol, 1-ethynyl-1-cyclopentanol, 1-ethynyl- 1-cyclohexanol, 1-propyn-3-cyclopropanol, 1-propyn-3-cyclobutanol, 1-propyn-3-cyclopentanol, 1-butyne-4-cyclobutanol, 1-pentyne-5-cyclopropanol Etc. are exemplified.

The above-mentioned x represents an integer greater than 0, y represents an integer greater than 0, and z represents an integer greater than 0, and is appropriately determined depending on the type of the central metal, the type of the organic sulfur ligand, and the like. . For example, when the organic sulfur-based ligand of the quaternary ammonium salt-type metal complex compound is a thiolate ligand (S
R ′) or a thioacetylene ligand (SC≡CR ′), when the central metal M is Au, x = 2, y
= 1 and z = 2, x = 1, y = 1 and z = 2 when M is Ag, x = 2, y = 1 and z = 4 when M is Pt,
When M is Cu, x = 1, y = 1 and z = 2 (or x =
2, y = 1 and z = 3), when M is Pd, x = 2, y
= 1 and z = 4, and when M is Ni, x = 2, y = 1 and z = 4.

In the production method of the present invention, the above-mentioned quaternary ammonium salt type metal complex compound is used as a starting material, and the central metal is reduced by the reductive elimination reaction of the organic sulfur-based ligand of this compound.

For example, [R ₄ N] [Au
The reaction in the case of using (SC ₁₂ H ₂₅ ) ₂ ] (R is an alkyl group) proceeds as follows. [R ₄ N] [Au (SC ₁₂ H ₂₅ ) ₂ ] → Au (−
R) + R ₃ N + (SC ₁₂ H ₂₅ ) ₂ That is, the thiolate ligand undergoes reductive elimination to form disulfide and gold, and simultaneously the decomposition of quaternary ammonium salt (pyrolysis) Some or all of the resulting alkyl groups form a protective layer around gold, and the ultrafine gold particles (Au having an average particle diameter of about 10
(-R)).

In the production method of the present invention, as long as the above-mentioned reductive elimination reaction occurs, the starting material may be treated by any operation method. Can be.

The conditions for the heat treatment are not particularly limited as long as such a reaction occurs, and may be appropriately set according to the type of starting materials, the use and purpose of the final product, and the like. In particular, heat treatment is preferably performed so that the content of the metal component in the ultrafine metal particles is 80% by weight or more. The upper limit of the content is not particularly limited, but may be usually about 95% by weight (the hydrocarbon group component is 5% by weight or more). In other words, the heat treatment may be performed so that the content of the metal component is about 80 to 95% by weight.

Accordingly, the heating temperature, heating time, heating atmosphere and the like also depend on the type of starting material, desired particle size, metal component content,
What is necessary is just to set in relation with the use of the final product. For example,
[C ₁₂ H ₂₅ N (CH ₃ ) ₃ ] [Au
(SC ₁₂ H ₂₅ ) ₂ ], when heated at 160 ° C. for about 7 hours in an atmosphere of an inert gas such as nitrogen gas,
Ultrafine gold particles (gold content of 90% by weight or more) in which a large number of particles having a particle size of 30 to 40 nm are distributed can be obtained.

After the reductive elimination reaction is completed, the ultrafine metal particles generally exist together with disulfide by-produced. The resulting disulfide is usually liquid,
Ultrafine metal particles are generated in such a manner as to precipitate in them. In this case, the ultrafine metal particles may be collected according to an ordinary solid-liquid separation method such as filtration and centrifugation, and may be washed with water, a solvent or the like as necessary. Further, if necessary, the ultrafine metal particles may be air-dried or force-dried.

The ultrafine metal particles of the present invention are ultrafine metal particles comprising a central portion and a protective layer around the central portion, wherein the central portion comprises a metal component and the protective layer comprises an organic component. .

When the organic component constituting the protective layer of the ultrafine metal particles is produced by the production method of the present invention, a hydrocarbon group component derived from a quaternary ammonium salt which is a counter cation of a starting material is usually used. contains. However, a component derived from an organic sulfur-based ligand may be included. In the present invention, it is particularly preferable that an alkyl group component having 1 to 20 carbon atoms is contained.

The metal component of the ultrafine metal particles of the present invention is not particularly limited, and is usually a transition metal (preferably Au, P
t, Cu, Ni or Pd) can be applied. When produced by the production method of the present invention, there is a metal component derived from the central metal of the quaternary ammonium salt type metal complex compound used as a starting material.

The content of the metal component can be appropriately changed depending on the use of the final product, the kind of the starting material, and the like, but is usually 80% by weight or more (preferably 80 to 95% by weight, more preferably 80 to 90% by weight). It is good.

The average particle size of the metal ultrafine particles of the present invention is not particularly limited, and can be appropriately set within the range of usually 100 nm or less (several tens to several nm) according to the use and purpose of the final product. In particular, in the present invention, ultrafine metal particles having an average particle diameter of 50 nm or less can be produced. The form of the metal ultrafine particles is not particularly limited, and may be any of a spherical shape, a polygonal shape, a flake shape, a columnar shape, and the like.

The ultrafine metal particles of the present invention can be produced more efficiently and reliably by, for example, the production method of the present invention. That is, the ultrafine metal particles of the present invention are particularly preferably produced by the above production method.

The ultrafine metal particles of the present invention are used for forming a metal film.
It can be used in various fields such as decoration and catalyst. In particular, metal film forming materials (specifically, electronic circuits,
It is most suitable for electronic materials such as electrodes and for other decoration). The form of use is not particularly limited, but the ultrafine metal particles of the present invention can be used as they are, or can be used by dispersing them in a solvent as needed. Further, as long as the effects of the present invention are not impaired, it is also possible to knead with a resin component, a solvent and the like to form a paste. The content of the ultrafine metal particles in the above material may be appropriately determined according to the type of the ultrafine metal particles used, the use of the final product, and the like.

As described above, the material for forming a metal film of the present invention contains the ultrafine metal particles of the present invention. This material is
Applicable to virtually any substrate. For example, it is applicable to plastics, ceramics, glass, papers, metals, and the like. In particular, since the material of the present invention can form a metal film at a relatively low temperature, it is suitable for plastics having low heat resistance. When applied to a substrate, application, drying, baking and the like may be performed according to a known method for forming an electronic circuit, an electrode, and the like, whereby a desired metal film can be obtained.

[0045]

According to the production method of the present invention, ultrafine metal particles having a nano-order particle size can be produced efficiently and reliably.

The ultrafine metal particles of the present invention have a unique structure in which the central portion is made of a metal component and the protective layer is made of an organic component. Can be maintained.

As a result, it is possible to efficiently and reliably form a metal film having no problem as in the prior art. In particular, when ultrafine metal particles are used for forming a metal film, the metal film can be formed at a low firing temperature of 400 ° C. or lower, which is applicable not only to the cost but also to a wide variety of base materials. But it is advantageous.

[0048]

The following examples are provided to further clarify the features of the present invention. The present invention is not limited to the scope of these examples.

Production Example 1 [C ₁₄ H ₂₉ N (CH ₃ ) ₃ ] [Au
(SC ₁₂ H ₂₅ ) ₂ ] was synthesized.

The gold chloride acid HAuCl ₄ · _4H 2 O (3.9
4 g, 9.56 mmol) in methanol (30 cm
³ ) has myristyltrimethylammonium bromide [C ₁₄ H ₂₉ N (CH ₃ ) ₃ ] Br (3.22 g,
A methanol solution (30 cm ³ ) of 9.57 mmol) was added dropwise and stirred for 3 hours. Thereafter, the methanol was removed under reduced pressure, concentrated, and distilled water (30 cm ³ ) was added. Then, the mixture was filtered with a Kiriyama funnel, washed with distilled water (30 cm ³ ), and subsequently with methanol (15 cm ³ ). After drying, [C ₁₂ H ₂₅ N (CH ₃ ) ₃ ] “AuCl ₄ ”
I got Methanol (40 cm ³ ) was added to this to form a suspension, and 1-dodecanethiol C ₁₂ H
_{25SH (7.74 g, 38.2 mmol) and sodium
Mumetilate CH 3} ONa (2.07 g, 38.2 mm
ol) in methanol containing solution (30 cm ³⁾ was reacted by adding dropwise at room temperature. After stirring for 13 hours, the resulting yellow-white precipitate was filtered off with a Kiriyama funnel, twice with distilled water (30 cm ³ × 2), and then twice with methanol (30 cm ³ ).
m ³ × 2) and further three times with diethyl ether (30 cm
³ × 3) After washing and drying under reduced pressure, the title precursor having the following physical properties was obtained.

[C ₁₄ H ₂₉ N (CH ₃ ) ₃ ] [Au
_(SC 12 _{H 25)} 2] Yield: 7.19 g Yield: 87.9% _{mp: 97.5~99.5 ℃ C 41 H 88 NS} 2 Au: Calculated C, 57.51%;
H, 10.36%; N, 1.64%, found C, 57.
49%; H, 9.95%; N, 1.91% 1 H-NMR: δ = 0.88 (t, 9H, C H 3 C
_{H 2), 1.24~1.26 (m,} 52H, CH 3 C H
_{2 C H 2 CH 2),} 1.39~1.32 (m, 6H, N
_{CH 2 CH 2 C H 2 CH} 2, SCH 2 CH 2 C H 2 CH
_{2), 1.66 (p, 4H} , SCH 2 C H 2 CH 2),
_{1.78 (p, 2H, NCH 2} C H 2 CH 2), 2.7
_{6 (t, 4H, SC H} 2 CH 2), 3.40 (s, 9
_{H, NC H 3), 3.54~3.62} (m, 2H, NC
H ₂ CH ₂ ) (The NMR spectrum was measured using deuterated chloroform (CDCl ₃ ) as a solvent and tetramethylsilane as an internal standard. The same applies hereinafter.) Production Example 2 Precursor [C ₁₂ H ₂₅ N (CH ₃ ) ₃ ] [Au (SC
_[12 H ₂₅ ) ₂ ] was synthesized in the same manner as in Example 1.
_{12 H 25 N (CH 3)} 3] methanol suspensions were prepared of [AuCl _4], were synthesized which is reacted with methanol solution containing 1-dodecanethiol and sodium methylate. [C ₁₂ H ₂₅ N (CH ₃ ) ₃ ] [Au (SC ₁₂ H
₂₅ ) ₂ ] Yield: 7.19 g Yield: 90.8% Melting point: 96.4-98.2 ° C C ₃₉ H ₈₄ NS ₂ Au: Calculated C, 56.56%;
H, 10.22%; N, 1.69%, found C, 55.
01%; H, 9.92%; N, 1.91% 1 H-NMR: δ = 0.88 (t, 9H, C H 3 C
_{H 2), 1.24~1.27 (m,} 48H, CH 3 C H
_{2 C H 2 CH 2),} 1.32~1.39 (m, 6H, N
_{CH 2 CH 2 C H 2 CH} 2, SCH 2 CH 2 C H 2 CH
_{2), 1.67 (p, 4H} , SCH 2 C H 2 CH 2),
_{1.79 (p, 2H, NCH 2} C H 2 CH 2), 2.7
_{6 (t, 4H, SC H} 2 CH 2), 3.41 (s, 9
_{H, NC H 3), 3.53~3.60} (m, 2H, NC
H ₂ CH ₂ ) Production Example 3 Precursor [(C ₁₈ H ₃₇ ) ₂ N (CH ₃ ) ₂ ] [Au
[(C ₁₈ H ₃₇ ) ₂ N (CH ₃ ) ₂ ] [AuC was synthesized in the same manner as in Example 1 for the synthesis of (SC ₁₂ H ₂₅ ) ₂ ].
[ ₄ ] was prepared by reacting a methanol solution containing 1-dodecanol and sodium methylate.

[(C ₁₈ H ₃₇ ) ₂ N (CH ₃ ) ₃ ]
[Au (SC ₁₂ H ₂₅ ) ₂ ] Yield: 8.80 g Yield: 74.2% Melting point: 86.0 to 91.0 ° C. C ₆₂ H ₁₃₀ NS ₂ Au: Calculated C, 64.71%;
H, 11.39%; N, 1.22%, found C, 63.
22%; H, 11.23%; N, 1.53% 1 H-NMR: δ = 0.88 (t, 12H, C H 3 CH
_{2), 1.24~1.35 (m, 88H} , CH 3 C H 2
_{C H 2 CH 2), 1.35~1.38} (m, 8H, NC
_{H 2 CH 2 C H 2 CH} 2, SCH 2 CH 2 C H 2 C
_{H 2), 1.64~1.75 (m,} 8H, NCH 2 C H
_{2 CH 2, SCH 2 C H} 2 CH 2), 2.76 (t, 4
H, SC H ₂ CH ₂ ), 3.32 (s, 6H, NC
_{H 3), 3.45~3.52 (m,} 4H, NC H 2 CH
₂ ) Example 1 Precursor [C ₁₄ H ₂₉ N (CH ₃ )] obtained in Production Example 1
₃ ] Ultrafine gold particles were produced by a reductive elimination reaction of [Au (SC _{12 H 25} ) ₂ ].

[C ₁₄ H ₂₉ N (CH ₃ ) ₃ ] [Au
_{(SC 12 H 25) 2]} (7.74g, 9.04mmo
l) was placed in a Pyrex three-necked flask, heated to 130 ° C. in an oil bath, and completely melted.
Until heated. Thereafter, the reaction was maintained at 160 ° C. for 9 hours, and then allowed to cool. The resulting brown powder was separated from liquid disulfide (SC ₁₂ H ₂₅ ) ₂ , washed twice with ethanol (30 cm ³ × 2), filtered off with a Kiriyama funnel, dried under reduced pressure, and dried under brown gold. Fine particles were obtained. The obtained ultrafine gold particles were observed with a transmission electron microscope (TEM), and the particle size distribution was determined based on the observation results. FIG. 1 shows the particle size distribution of the obtained ultrafine gold particles.

As shown in FIG. 1, the quaternary ammonium salt type metal complex compound is subjected to a heat treatment (thermal decomposition),
It can be seen that ultrafine metal particles having a central distribution with a particle size of 30 to 40 nm can be obtained.

Example 2 Example 1 was repeated using the precursor obtained in Production Example 1 except that the heating temperature was 180 ° C. and the holding time at 180 ° C. was 9 hours.
Ultrafine gold particles were produced in the same manner as described above. The particle size distribution of the obtained ultrafine gold particles was determined in the same manner as in Example 1. The result is shown in FIG. As is clear from the results of FIG.
In the present invention, it is also found that the particle size of the ultrafine metal particles can be controlled by the heating temperature and the heating time.

FIG. 2 shows the result (TEM image) of the ultrafine gold particles obtained in Example 2 observed with a transmission electron microscope. According to FIG. 2, it is found that ultra-fine spherical gold particles having a particle diameter of about 50 nm or less are generated.

Example 3 The precursor obtained in Production Example 2 [C ₁₂ H ₂₅ N (CH ₃ )]
₃ ] [Au (SC _{12H 25} ) ₂ ] and a heating temperature of 1
Except that the holding time at 60 ° C. and 160 ° C. was 7 hours,
Ultrafine gold particles were produced in the same manner as in Example 1. The particle size distribution of the obtained ultrafine gold particles was determined in the same manner as in Example 1. The result is shown in FIG.

Example 4 The precursor [(C ₁₈ H ₃₇ ) ₂ N (C
H _{3) 2]} using _{[Au (SC 12 H 25)} 2], addition to the retention time 6 hours at a heating temperature 170 ° C. and 170 ° C., the manufactures ultrafine gold particles in the same manner as in Example 1 Was. The particle size distribution of the obtained ultrafine gold particles was determined in the same manner as in Example 1. The result is shown in FIG.

FIG. 3 shows the results of powder X-ray diffraction analysis of the ultrafine gold particles obtained in Example 4.

Example 5 Except that the heating temperature was 190 ° C. and the holding time at 190 ° C. was 6 hours, the production of ultrafine gold particles was performed in the same manner as in Example 4 using the precursor obtained in Production Example 3. went. The particle size distribution of the obtained ultrafine gold particles was determined in the same manner as in Example 1. The result is shown in FIG.

[Brief description of the drawings]

FIG. 1 is a diagram showing the particle size distribution of ultrafine gold particles obtained in each Example.

FIG. 2 shows a TEM image of ultrafine gold particles obtained in Example 2.

FIG. 3 is a view showing the results of powder X-ray diffraction analysis of ultrafine gold particles obtained in Example 4.

Claims (10)

[Claims] [1] The general formula [R ¹ R ² R ³ R ⁴ N] _x [M
_y (A) _z ] (provided that R ^{1 to} R ⁴ are the same or different hydrocarbon groups and may have a substituent, M is a transition metal, and A is an organic sulfur-based coordination. And x is an integer greater than 0, y is an integer greater than 0, and z is an integer greater than 0.) A quaternary ammonium salt type metal complex compound represented by the following formula: A method for producing ultrafine metal particles, comprising reducing a central metal from a reductive elimination reaction of a system ligand. 2. The formula [R ¹ R ² R ³ R ⁴ N] _x [M
_y (A) _z ] (provided that R ^{1 to} R ⁴ are the same or different hydrocarbon groups and may have a substituent, M is a transition metal, and A is an organic sulfur-based coordination. And x is an integer greater than 0, y is an integer greater than 0, and z is an integer greater than 0.) A quaternary ammonium salt type metal complex compound represented by the following formula: A method for producing fine particles. 3. The production method according to claim 1, wherein disulfide is formed together with the ultrafine metal particles. 4. The organic sulfur-based ligand is a thiolate ligand (S
R ′) or a thioacetylene ligand (SC≡CR ′) (in each case, R ′ is a hydrocarbon group which may have a substituent). The production method according to any one of the above. 5. The method according to claim 1, wherein M is Au, Pt, Cu, Ni or Pd. 6. An organic component in the obtained ultrafine metal particles comprising a hydrocarbon group component derived from [R ¹ R ² R ³ R ⁴ N] which is a counter cation of a quaternary ammonium salt type metal complex compound. 6. The production method according to any one of 1 to 5. 7. A heat treatment is performed so that the content of the metal component in the obtained ultrafine metal particles is 80 to 95% by weight.
7. The method according to any one of items 1 to 6, above. 8. Ultrafine metal particles comprising a central portion and a protective layer around the central portion, wherein the central portion comprises a metal component and the protective layer comprises an organic component. 9. The ultrafine metal particles according to claim 7, wherein the content of the metal component is 80% by weight or more. 10. A material for forming a metal film, comprising the ultrafine metal particles according to claim 8.