Nanoscale metal complex capable of controlling volume change and method for producing same

Abstract

The present invention provides a nano-sized metal complex in which volume change on the occasion of temperature change is suppressed. The present invention pertains to a metal complex that has a crystallite diameter of 60 nm or less and is represented by general formula (1).　Formula (1): (M1)p[(M2)q(CN)6•nH2O (in the formula, M1 represents at least one item selected from the group consisting of Ag (I), Au (I), and Cu (I), M2 represents at least one trivalent transition metal, p is a positive number between 2.5 and 3.5 inclusive, q is a positive number between 0.5 and 1.5 inclusive, p + q is a positive number between 3.5 and 4.5 inclusive, and n is 0 or a positive number).

Description

Nanoscale metal complex capable of controlling volume change and method for producing same

[0001] The present invention relates to a nanoscale metal complex capable of controlling volume change and a method for producing the same.

[0002] It is known that many materials increase in length and volume due to thermal expansion when the temperature rises. The volume expansion of materials due to temperature changes can lead to deformation and cracks, posing a major challenge for industrial use. In contrast, materials that exhibit negative thermal expansion (hereinafter sometimes referred to as "negative thermal expansion materials"), which shrink in volume when heated, are also known. It is known that materials that exhibit negative thermal expansion can be used together with other materials to suppress changes in the thermal expansion of materials due to temperature changes.

[0003] Materials that exhibit negative thermal expansion include, for example, β-eucryptite, zirconium tungstate (ZrW2O8), zirconium tungstate phosphate (Zr2WO4(PO4)2), Zn x Cd 1-x (CN)2, manganese nitride (for example, Patent Document 1), bismuth-nickel-iron oxide, etc. are known.

[0004] The thermal expansion coefficient of zirconium tungstate phosphate is −3.4 to −3.0 ppm / K in the temperature range of 0 to 400°C, which means that it has a large negative thermal expansion property. By using it in combination with a material that exhibits positive thermal expansion (hereinafter, also referred to as a “positive thermal expansion material”), it is possible to produce a material with low thermal expansion (see, for example, Patent Documents 2 to 5).

[0005] Japanese Patent No. 5553366 Japanese Patent Application Laid-Open No. 2005-35840 Japanese Patent Application Laid-Open No. 2015-10006 Japanese Patent Application Laid-Open No. 2020-2000 Japanese Patent No. 6105140

[0006] However, because it is difficult to suppress thermal expansion itself with conventional technology, when using a thermally expanding material, it was necessary to design it under the assumption that a material with negative thermal expansion would also be used. As a result, there was room for improvement in the development of a material that does not change volume when the temperature changes and that suppresses thermal expansion itself.

[0007] An object of the present invention is to provide a nano-sized metal complex that is suppressed from changing in volume when the temperature changes.

[0008] As a result of extensive research to solve the above problems, the inventors discovered that by nanosizing a Prussian blue analogue, volume changes caused by temperature changes can be suppressed. Based on this finding, they conducted further research and completed the present invention.

[0009] That is, the present invention includes the following inventions: [1] A metal complex having a crystallite diameter of 60 nm or less and represented by the following general formula (1): (M 1 ) p [(M 2 ) q (CN)6]・nH2O (1) (wherein, M 1 represents at least one selected from the group consisting of Ag(I), Au(I), and Cu(I); M 2 represents at least one trivalent transition metal, p is a positive number of 2.5 or more and 3.5 or less, q is a positive number of 0.5 or more and 1.5 or less, p + q is a positive number of 3.5 or more and 4.5 or less, and n is 0 or a positive number.) [2] M 2 The metal complex according to [1], wherein the transition metal constituting M is at least one selected from the group consisting of Ti, V, Cr, Mn, Fe, Co, Rh, and Ir. 2 The metal complex according to [1] or [2], wherein the transition metal constituting M is Co. [4] 1 [5] The metal complex according to [1] or [2], wherein M is Ag(I). 1 [6] The metal complex according to [1] or [2], wherein M is Cu(I). 2 is Fe. [7] The metal complex according to [1] or [2], wherein p is 3 and q is 1. [8] The metal complex according to [1] or [2], wherein the crystallite size is 40 nm or less. [9] A composite comprising the metal complex according to [1] or [2] and a support.

[10] A composite comprising a monovalent metal cation (M 1 a solution containing the metal cation (M) and a solution containing the metal cyano complex, 1) is at least one selected from the group consisting of Ag(I), Au(I), and Cu(I), and the solution containing the metal cyano complex contains at least one transition metal (M 2 ), (i) the transition metal (M 2 ) to the metal cation (M 1 ) molar ratio (M 1 / M 2 (ii) the transition metal (M 2 ) to the metal cation (M 1 ) molar ratio (M 1 / M 2 ) is less than 1.0, and the metal cation (M 1 The method for producing a metal complex according to [1] or [2], wherein the concentration of the metal salt in the solution containing the monovalent metal cation (M) is 0.0001 to 0.1 mol / L.

[11] 1

[12] The method for producing a metal complex according to

[10] , wherein the solution containing the metal cation (M) and the solution containing the metal cyano complex are mixed by adding them all at once. 1

[13] The method for producing a metal complex according to

[11] , wherein a solution containing a metal cyano complex is added to a solution containing the transition metal (M 2

[14] The method for producing a metal complex according to

[10] , wherein the transition metal (M) is at least one selected from the group consisting of Ti, V, Cr, Mn, Fe, Co, Rh, and Ir.

[15] The method for producing a metal complex according to

[10] , wherein no surfactant is used. 2 ) to the metal cation (M 1 ) molar ratio (M 1 / M 2

[16] The method for producing a metal complex according to

[11] , wherein the metal cation (M 1

[17] The method for producing a metal complex according to

[10] , wherein the temperature during mixing of the solution containing the metal cation (M) with the solution containing the metal cyano complex is −5 to 180° C. 1

[18] The method for producing a metal complex according to

[10] , wherein the transition metal (M 2

[11] The method for producing a metal complex according to

[10] , wherein the transition metal constituting the metal complex is Co.

[0010] The present invention provides a nanosized metal complex that exhibits reduced volume change upon temperature change. Furthermore, the metal complex of the present invention exhibits particularly low volume change at low temperatures (e.g., below 0°C), making it particularly advantageous for use in low-temperature regions. Furthermore, the metal complex of the present invention exhibits different thermal expansion coefficients during the first heating and cooling process and the second heating and cooling process. Repeated heating and cooling enhances the effect of suppressing volume change upon temperature change. Therefore, using the metal complex of the present invention as a product enhances the effect of suppressing cracks, deformation, and the like in the product due to volume change, thereby improving safety, making it particularly advantageous from an industrial perspective. Furthermore, the production method of the present invention enables the production of nanosized metal complexes that exhibit reduced volume change upon temperature change under mild conditions, eliminating the need for high-temperature and high-pressure conditions, making it industrially advantageous. Furthermore, the production method of the present invention enables the suppression of particle size variation.

[0011] 1 shows the results of scanning electron microscope (SEM) observation of the metal complexes according to Examples 1 and 2 and Comparative Example 1. FIG. 2 shows the results of measurement of the amount of change in unit lattice volume of the metal complexes according to Examples 1 and 2 and Comparative Example 1. FIG. 3 shows the results of measurement of the amount of change in lattice constant and unit lattice volume of the metal complexes of the Examples and Reference Example. FIG. 4 shows the results of calculation of the thermal expansion coefficient of the metal complexes of the Examples. FIG. 5 is a schematic diagram showing the sampling temperatures of various measurements in Example 3. FIG. 6 is a schematic diagram showing the results of measurement of the amount of change in lattice constant and unit lattice volume of the metal complexes of Example 3. FIG. 7 is a schematic diagram showing the results of calculation of the thermal expansion coefficient of the metal complexes of Example 3. FIG. 8 is a schematic diagram showing the sampling temperatures of various measurements in Example 4. FIG. 9 is a schematic diagram showing the results of measurement of the amount of change in lattice constant and unit lattice volume of the metal complexes of Example 4. FIG. 10 is a schematic diagram showing the results of calculation of the thermal expansion coefficient of the metal complexes of Example 4. FIG. 11 is a schematic diagram showing the sampling temperatures of various measurements in Example 5. FIG. 12 is a schematic diagram showing the sampling temperatures of various measurements in Example 6.

[0012] The metal complex of the present invention has a crystallite diameter of 60 nm or less and is represented by the following general formula (1): (M 1 )p [(M 2 ) q (CN)6]・nH2O (1) (wherein, M 1 represents at least one selected from the group consisting of Ag(I), Au(I), and Cu(I); M 2 represents at least one metal (for example, a trivalent transition metal or aluminum, preferably a trivalent transition metal), p is a positive number of 2.5 or more and 3.5 or less, q is a positive number of 0.5 or more and 1.5 or less, p+q is a positive number of 3.5 or more and 4.5 or less, and n is 0 or a positive number.

[0013] The reason why the metal complex of the present invention can suppress volume change when temperature changes is unclear, but is presumed to be as follows. Generally, when heat is applied to many substances, the vibration amplitude of the atoms constituting the substance increases with temperature rise. This increases the interatomic distance to prevent collisions between the atoms, causing the substance itself to expand, a phenomenon known as "thermal expansion." On the other hand, the metal complex of the present invention belongs to a group of compounds known as Prussian blue analogues (PBAs), and is a cyano-bridged metal complex having a cyano-bridged structure. It is known that Ag3[Co(CN)6], a Prussian blue analogue, undergoes an anisotropic volume change when heated (Science, 2008, Vol. 319, Issue 5864, pp. 794-797). In the metal complex of the present invention, the monovalent metal cation and the transition metal ion have a crosslinked structure in which they are three-dimensionally crosslinked by cyano groups, and thus act cooperatively. When heat is applied, the vibration of multiple metal atoms is suppressed, the anisotropic expansion and contraction of the atoms is slowed, and volume change is thought to be suppressed. Furthermore, although the metal complex of the present invention exhibits a volume change suppression effect immediately after synthesis, the uniformity of the bonding state within the metal complex is low. In contrast, when the metal complex of the present invention experiences a temperature history of heating and cooling, the uniformity of the bonding state between atoms in the crosslinked structure within the metal complex is increased, and the volume change suppression effect can be improved.

[0014] In this specification, the term "transition metal" refers to a metal element present in the group 3 to 12 elements of the periodic table. Specifically, the term "transition metal" refers to the first transition metal elements such as Sc (scandium), Ti (titanium), V (vanadium), Cr (chromium), Mn (manganese), Fe (iron), Co (cobalt), Ni (nickel), Cu (copper), and Zn (zinc); the second transition metal elements such as Y (yttrium), Zr (zirconium), Nb (niobium), Mo (molybdenum), Tc (technetium), Ru (ruthenium), Rh (rhodium), Pd (palladium), Ag (silver), and Cd (cadmium); La (lanthanum), Ce (cerium), , Pr (praseodymium), Nd (neodymium), Pm (promethium), Sm (samarium), Eu (europium), Gd (gadolinium), Tb (terbium), Dy (dysprosium), Ho (holmium), Er (erbium), Tm (thulium), Yb (ytterbium), Lu (lutetium), Hf (hafnium), Ta (tantalum), W (tungsten), Re (rhenium), Os (osmium), Ir (iridium), Pt (platinum), Au (gold), and Hg (mercury) are examples of third transition metal elements. Among these transition metals, the trivalent transition metal is M in the general formula (1) according to the metal complex of the present invention. 2 In this specification, the term "crystallite" refers to the smallest unit of a crystal grain that can be regarded as a single crystal. In this specification, the crystallite size refers to the domain size of a single crystal in a crystal, and is a value calculated from the measured values ​​of X-ray diffraction (XRD). Detailed calculation methods are as described in the Examples below. Depending on the line width of the peak measured by XRD, the crystallite size can be more accurately determined by confirming the crystallite size by electron microscope observation (e.g., SEM observation) in addition to the measurement by XRD. In addition, when two or more crystal faces are observed by XRD, the smaller value of the crystallite size calculated by the method described in the Examples below (the smallest value when three or more crystal faces are present) can be used as the crystallite size. In this specification, the upper and lower limits of the numerical ranges (contents of each component, values ​​calculated from each component, and each physical property, etc.) can be appropriately combined.

[0015] In the metal complex of the present invention, M 2 The metal constituting M may be one kind or two or more kinds. 2 The metal constituting the metal is preferably aluminum, a first transition metal element, and / or a second transition metal element, more preferably a first transition metal element and / or a second transition metal element, further preferably at least one selected from the group consisting of Ti, V, Cr, Mn, Fe, Co, Rh, and Ir, and most preferably at least one selected from the group consisting of Cr, Fe, and Co, in terms of making it easier to achieve the effects of the present invention.

[0016] In the general formula (1) of the metal complex of the present invention, M 1 represents a monovalent metal, and is at least one selected from the group consisting of Ag(I), Au(I), and Cu(I). 1 ) is a metal ion (M 2 ) and a crosslinked structure three-dimensionally crosslinked by a cyano group, they can act cooperatively, and as a result, volume change is suppressed when the temperature changes, and further, by repeating temperature increases and decreases, the effect of suppressing volume change when the temperature changes can be enhanced. 1 It is important that is at least one selected from the group consisting of Ag(I), Au(I), and Cu(I).

[0017] In general formula (1), p is a positive number of 2.5 or more and 3.5 or less, q is a positive number of 0.5 or more and 1.5 or less, p + q is a positive number of 3.5 or more and 4.5 or less, and n is 0 or a positive number. In general formula (1), p is preferably 3.0 and q is 1.0 from the viewpoint of a higher effect of suppressing volume change when temperature changes, but there is a possibility of some deviation in composition, and such an embodiment is also encompassed by the present invention. In general formula (1), from the viewpoint of easily achieving the effects of the present invention, p is preferably a positive number of 2.7 or more and 3.3 or less, more preferably a positive number of 2.8 or more and 3.2 or less, and even more preferably a positive number of 2.85 or more and 3.15 or less. In general formula (1), from the viewpoint of easily achieving the effects of the present invention, q is preferably a positive number of 0.7 or more and 1.3 or less, more preferably a positive number of 0.8 or more and 1.2 or less, and even more preferably a positive number of 0.75 or more and 1.25 or less. In general formula (1), in order to easily obtain the effects of the present invention, p + q is preferably a positive number of 3.7 or more and 4.3 or less, more preferably a positive number of 3.8 or more and 4.2 or less, and even more preferably a positive number of 3.85 or more and 4.15 or less. The positive number in n is not particularly limited as long as it is a value that can be taken as a hydrate, and may be, for example, 1 or more, 2 or more, or 3 or more. An example of an embodiment is a metal complex in which n is 0 in general formula (1).

[0018] In a preferred embodiment, in general formula (1), M 2 The metal constituting the metal is a first transition metal element and / or a second transition metal element. 2 In another preferred embodiment, the metal constituting M is a transition metal. 2 In another preferred embodiment, the transition metal constituting the metal complex is at least one selected from the group consisting of Ti, V, Cr, Mn, Fe, Co, Rh, and Ir. 2 In another preferred embodiment, the transition metal constituting the metal complex is Co.1 is Ag. Still another preferred embodiment is a metal complex in which p is 3 and q is 1. Furthermore, a particularly preferred embodiment is a metal complex in which M 1 is Ag, and M 2 is at least one transition metal selected from the group consisting of Cr, Fe and Co, p is 3, and q is 1.

[0019] The metal complex of the present invention may be, for example, M 1 is Ag(I), and M 2 is at least one selected from the group consisting of Cr, Fe, and Co, p is 3, and q is 1, Ag3[Co 0.67 Fe 0.33 (CN)6]. That is, the metal complex of the present invention is a metal complex in which q is 1 and M 2 When the metals constituting the compound (preferably trivalent transition metals) are two or more types, the compound also includes a metal complex in which the total number of metals is 1.

[0020] In the metal complex of the present invention, the crystallite diameter is 60 nm or less. The crystallite diameter is preferably 50 nm or less, more preferably 40 nm or less, even more preferably 30 nm or less, particularly preferably 25 nm or less, and most preferably 22 nm or less. The lower limit of the crystallite diameter is not particularly limited, but is preferably 1 nm or more, more preferably 2 nm or more, even more preferably 3 nm or more, and particularly preferably 5 nm or more. The smaller the crystallite diameter, the more effectively volumetric change can be suppressed during temperature changes. Furthermore, the smaller the crystallite diameter, the more effectively the effect of suppressing volumetric change of the metal complex by repeated temperature increases and decreases can be enhanced. In a preferred embodiment, the crystallite diameter is 25 nm or less, from the viewpoint of a higher effect of suppressing volumetric change during temperature changes, and is represented by the general formula (1), and in the general formula (1), M 1 represents at least one selected from the group consisting of Ag(I), Au(I), and Cu(I); M 2represents at least one selected from the group consisting of Cr, Fe and Co, p is a positive number of 2.5 or more and 3.5 or less, q is a positive number of 0.5 or more and 1.5 or less, p + q is a positive number of 3.5 or more and 4.5 or less, and n is 0 or a positive number. The crystallite size is measured using the measurement method and conditions described in the Examples below, and means the smaller value of the crystallite size calculated using the method described in the Examples below (when three or more crystal faces exist, the smallest value).

[0021] The crystallite size is determined by the amount of the transition metal (M 2 ) to the metal cation (M 1 ) molar ratio (M 1 / M 2 ), metal cations (M 1 The concentration of the metal salt in the solution containing the metal cyano complex can be adjusted by adjusting the concentration of the metal salt in the solution containing the metal cyano complex.

[0022] The metal complex of the present invention has a change in unit cell volume (absolute value) of 6 Å when the temperature is increased from 100 K at a rate of 5° C. / min, as calculated from the XRD pattern by Rietveld analysis at 100 to 300 K. 3 Preferably, it is 5 Å or less. 3 More preferably, it is 4 Å or less. 3 More preferably, it is 3 Å or less. 3 It is particularly preferable that the following is true: The method for calculating the change in unit cell volume is as described in the Examples below.

[0023] The metal complex of the present invention may be in the form of an aggregate or a dispersion. The form of the metal complex can be appropriately selected depending on the method of collection after production. The method of collection after production can be a known method and is not particularly limited. When preparing a dispersion, a solvent can be used. The solvent is not particularly limited, and examples thereof include water and organic solvents. As the organic solvent, a solvent for dissolving a metal cation (M 1 The organic solvent may be the same as that used in the solution containing the hydroxybenzoate.

[0024] Another embodiment is a composite comprising the metal complex of the present invention and a carrier. In the composite of the present invention, the type of carrier is not limited as long as it can be used as a support (substrate) capable of supporting the metal complex. The carrier is preferably a liquid or solid at room temperature, more preferably a solid. Since the metal complex of the present invention can suppress volume changes when the temperature changes, pretreatment (e.g., heat treatment, etc.) that takes into account changes in the metal complex due to temperature changes is not required when producing the composite. The composite can be easily produced by fixing the metal complex on the carrier without considering temperature changes. The method for fixing the metal complex on the carrier is not particularly limited, and known methods and devices can be used.

[0025] The support may be at least one selected from the group consisting of polymers, chalcogen compounds, metal compounds, metals, and solid carbon materials. One support may be used alone, or two or more supports may be used in combination. Commercially available supports may be used.

[0026] The polymer may be either a natural polymer or a synthetic polymer. Examples of natural polymers include organic natural polymers such as natural rubber, protein, starch, and cellulose; and inorganic natural polymers such as quartz, mica, and feldspar. Examples of synthetic polymers include organic synthetic polymers such as polyacrylic acid, polymethacrylic acid, polyvinyl alcohol, polyvinyl chloride, polyvinylpyrrolidone, polyethylene glycol (PEG), polypropylene glycol (PPG), polyethylene terephthalate (PET), polyester, polyethylene, polypropylene, polystyrene, polyurethane, polyethyleneimine, polyethersulfone, polyphenylene sulfide (PPS), polyether ether ketone (PEEK), polyvinylidene fluoride, polylactic acid, epoxy resin, phenolic resin, fluorine-based resin (e.g., PTFE (polytetrafluoroethylene), PFA, FEP, PCTFE, ETFE, and ECTFE), nylon resin, polyamide resin, polyimide resin, and rubber (e.g., silicone rubber, nitrile rubber, butyl rubber, and butadiene rubber); and inorganic synthetic polymers such as glass, silica gel, and silicone resin. The synthetic polymer may be a homopolymer having one type of monomer as a constituent unit, or a copolymer having two or more types of monomer as constituent units. The polymer may be a thermoplastic resin or a thermosetting resin. The weight-average molecular weight (Mw) of the polymer is not particularly limited, and may be an oligomer or polymer of 1,000 to less than 10,000, 10,000 to less than 1,000,000, or an ultra-high molecular weight polymer of 1,000,000 to 7,000,000. The weight-average molecular weight refers to the weight-average molecular weight in terms of polystyrene determined by gel permeation chromatography (GPC).

[0027] The chalcogen compound refers to a compound containing a Group 16 element (oxygen, sulfur, selenium, tellurium, polonium, livermorium). The Group 16 element contained in the chalcogen compound may be one type alone or two or more types. The chalcogen compound is not particularly limited, and includes, for example, HZ 1 O4 (Z 1 = chalcogens excluding tellurium), H6TeO6, H2Z 2 O3 (Z 2a compound having the structure of R = chalcogen) or a salt thereof, 1 Z3 (wherein, R 1 is Ti, Zr, Hf, V, Nb, Ta, Mo, or W, and Z is S or Se), 2 PZ3 (in the formula, R 2 is Mg, V, Mn, Fe, Co, Ni, Zn, Cd, or In, and Z is S or Se).

[0028] The metal compound is not particularly limited, but examples thereof include oxides of La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Y, Si, Zr, Fe, Ti, Al, Mg, Co, Ni, Mn, Cr, Mo, W, V, Zn, and Sn, solid solutions thereof, and composite oxides thereof. Specific examples include SiO, TiO, and AlO. In the present invention, semimetals in the periodic table, such as "Si," are included in the metals. The metal compound used in the carrier may contain any of the above-mentioned metal compounds, and may also be, for example, a cement material such as Portland cement (containing tricalcium silicate [(CaO)3(SiO2)], dicalcium silicate [(CaO)2(SiO2)], tricalcium aluminate [(CaO)3(Al2O3)], and tetracalcium aluminoferrate [(CaO)4(Al2O3)(Fe2O3)]).

[0029] Metals include Fe and metal alloys (stainless steel, etc.), which can be used as metallic supports.

[0030] Examples of solid carbon materials include silicon carbide (SiC), activated carbon, graphite, diamond, fullerene, carbon nanotubes, graphene, and amorphous carbon.

[0031] The shape and size of the carrier can be changed depending on the form of use and are not particularly limited. For example, the carrier may be in the form of a sheet, film, nonwoven fabric, or flat plate. The size (length) of the carrier may be, for example, a solid carrier (e.g., sheet-shaped) sufficiently larger than the size of the metal complex particles. The size (length) of the carrier may be nano-sized, and may be 1 μm or more, 1 mm or more, or 1 cm or more. The carrier may be, for example, a nanosheet (e.g., about 1 nm to 100 nm thick).

[0032] Hereinafter, in the method for producing a metal complex, M 2 In the preferred embodiment, the metal complex of the present invention is prepared by adding a metal cation (M 1 a solution containing the metal cation (M) and a solution containing the metal cyano complex, 1 ) is a solution containing metal cations (M 1 ), and the metal cation (M 1 ) is at least one selected from the group consisting of Ag(I), Au(I), and Cu(I), and the solution containing the metal cyano complex contains a transition metal (M 2 ), (i) the transition metal (M 2 ) to the metal cation (M 1 ) molar ratio (M 1 / M 2 ) is greater than 2.6, or (ii) the transition metal (M 2 ) to the metal cation (M 1 ) molar ratio (M 1 / M 2 ) is less than 1.0, and the metal cation (M 1 The concentration of metal salts (metal cations (M 1 The reason why the metal complex according to the present invention can be obtained by these production methods is not clear, but is thought to be as follows. 1 and M 2When the ratio is close to the stoichiometric ratio, the crystallite size of the particles that make up the metal complex becomes large, but when the ratio is significantly different from the stoichiometric ratio, the crystallite size of the particles that make up the metal complex becomes small, resulting in the formation of nanoparticles. This is thought to be because the larger component functions as a capping agent, suppressing the growth of crystals.

[0033] In the method for producing a metal complex according to the present invention, in both the first and second embodiments described below, a metal cation (M 1 When a solution containing a metal cyano complex is mixed with a solution containing a monovalent metal cation (M), the bulk addition allows a large amount of the larger component to be instantly present in the system, thereby significantly enhancing the function of the component as a capping agent, thereby making it possible to broaden the line width of the peak measured by XRD of the obtained metal complex, reduce the crystallite diameter of the metal complex, and achieve a more excellent effect of inhibiting volume change when the temperature changes, and furthermore, when the metal complex experiences a temperature history of temperature increase and decrease, the uniformity of the bonding state between atoms in the crosslinked structure of the metal complex is increased, thereby further improving the effect of inhibiting volume change, so that bulk addition is preferred. 1 The mixing of a solution containing the metal cation (M) with a solution containing a metal cyano complex can broaden the line width of the peak measured by XRD of the obtained metal complex, can reduce the crystallite diameter of the metal complex, and can exhibit a more excellent effect of suppressing volume change when the temperature changes. Furthermore, when the metal complex experiences a temperature history of increasing and decreasing the temperature, the uniformity of the bonding state between atoms in the crosslinked structure of the metal complex is increased, and the effect of suppressing volume change can be further improved. 1 It is more preferable that the mixing is an operation of adding a solution containing a metal cyano complex to a solution containing the metal cation (M 1 It is more preferable that the solution containing the metal cyano complex is added all at once to the solution containing the metal cyano complex. Furthermore, the method for producing a metal complex according to the present invention is industrially advantageous in that it does not require the addition of any additional component such as a capping agent to suppress the growth of crystal grains.

[0034] In one embodiment of the method for producing a metal complex according to the present invention, (i) the metal (M 2 ) to the metal cation (M 1 ) molar ratio (M 1 / M 2 ) (for example, Ag / Co ratio) is preferably greater than 2.6. In this specification, this embodiment is also referred to as "first embodiment."

[0035] In the first embodiment, the molar ratio (M 1 / M 2 The molar ratio (M 1 / M 2 The upper limit of (a) is not particularly limited, but is preferably 1000 or less, more preferably 500 or less, and even more preferably 200 or less. When it is within the above range, a desired nano-sized metal complex can be easily obtained.

[0036] Metal cations (M 1 A solution containing a metal salt (M) can be obtained by dissolving the metal salt in a solvent. Examples of the metal salt include organic salts such as aliphatic carboxylates and aromatic carboxylates; and inorganic salts such as carbonates, nitrates, hydrochlorides, sulfates, phosphates, and chlorides. These salts may be used alone or in combination of two or more. The metal cations (M) contained in the metal salt can be used alone or in combination of two or more. 1 ) may be at least one selected from the group consisting of Ag(I), Au(I), and Cu. Specific examples of the metal salt include silver(I) nitrate, silver(I) sulfate, gold(I) chloride, copper(I) nitrate, and copper(I) sulfate.

[0037] Metal cations (M 1The solvent used in the solution containing the metal salt is not particularly limited, but examples include water and organic solvents, with water being preferred. The solvents may be used alone or in combination of two or more. For example, a polar solvent may be used alone, or a polar solvent and a non-polar solvent may be used in combination, taking into consideration the solubility of the metal salt. Examples of organic solvents include non-aromatic hydrocarbon solvents (e.g., alkanes such as pentane, hexane, heptane, octane, nonane, decane, dodecane, isododecane, and tridecane, cycloalkanes such as cyclohexane and methylcyclohexane, decahydronaphthalene, and liquid paraffin); aromatic hydrocarbon solvents (e.g., benzene, toluene, xylene, diethylbenzene, mesitylene, tetralin, indene, naphthalene, and methylnaphthalene); halogenated hydrocarbon solvents (e.g., dichloromethane, dichloroethane, chloroform, and chlorobenzene); and alcohol solvents (e.g., monohydric alcohols such as ethanol, propanol, 1-butanol, 2-butanol, 1-heptanol, 2-heptanol, 3-heptanol, 1-hexanol, 2-hexanol, benzyl alcohol, and oleyl alcohol; and polyhydric alcohols such as ethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, and glycerin). ether solvents (e.g., diethyl ether, diisopropyl ether, methyl t-butyl ether, diisoamyl ether, ethylene glycol derivatives (e.g., monoglyme (ethylene glycol dimethyl ether), methyl cellosolve, diethyl cellosolve, diglyme, diethylene glycol monoethyl ether, diethylene glycol diethyl ether, triglyme, tetraglyme, diethylene glycol monobutyl ether, triethylene glycol monomethyl ether, ethylene glycol monobenzyl ether, ethylene glycol monophenyl ether, diethylene glycol monobenzyl ether, poly(ethylene glycol) monomethyl ether), propylene glycol derivatives (e.g., 3-hexanol propylene glycol monopropyl ether, dipropylene glycol monoethyl ether, tripropylene glycol monomethyl ether), 1,1-dimethoxycyclohexane, phenetole, veratrole, dioxane, tetrahydrofuran);Ester solvents (e.g., ethyl acetate, butyl acetate, isopropyl acetate, 3-methoxy-3-methylbutyl acetate, dimethyl carbonate, diethyl malonate, ethylene carbonate, propylene carbonate, γ-butyrolactone, α-acetyl-γ-butyrolactone); ketone solvents (e.g., acetone, methyl ethyl ketone, methyl isobutyl ketone, diisobutyl ketone, acetophenone, propiophenone, isophorone); Examples of such solvents include sulfur-containing solvents (e.g., dimethyl sulfoxide, sulfolane, diphenyl sulfide); and nitrogen-containing solvents (e.g., amide solvents such as N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, 1,3-dimethyl-2-imidazolidinone, N,N-dimethylacrylamide, N,N-dimethylacetoacetamide, N,N-diethylformamide, N,N-diethylacetamide, hexamethylphosphoramide, and methylpyrrolidone, amine solvents such as triethanolamine, and nitrile solvents such as acetonitrile and benzonitrile; nitro solvents such as nitrobenzene and o-nitrotoluene; quinoline, tetrahydroquinoline, and dimethylimidazolidinone).

[0038] Metal cations (M 1 Examples of the solution containing silver(I) nitrate, silver(I) sulfate, copper(I) nitrate, copper(I) sulfate, etc.

[0039] In the first embodiment, a metal cation (M 1 The concentration of the metal salt in the solution containing the metal salt is determined by the molar ratio (M 1 / M 2 ) and easily adjust the crystallite size to a desired value, the concentration is preferably 0.003 mol / L or more, more preferably 0.01 mol / L or more, and even more preferably 0.1 mol / L or more. In addition, the concentration of the metal salt in the solution containing the metal cation is preferably 0.003 mol / L or more, more preferably 0.01 mol / L or more, and even more preferably 0.1 mol / L or more. 1 / M 2 ) and easily adjusts the crystallite size to a desired value, the concentration is preferably 8 mol / L or less, more preferably 5 mol / L or less, and even more preferably 3 mol / L or less.

[0040] Examples of metal cyano complexes used in the solution containing a metal cyano complex include K3[Al(CN)6], K3[Mn(CN)6], K3[Fe(CN)6], K3[Co(CN)6], etc. Metal cyano complexes suitable for the type of transition metal can be used. One type of metal cyano complex may be used alone, or two or more types may be used in combination.

[0041] The concentration of the metal cyano complex in the solution containing the metal cyano complex is not particularly limited, but may be in the range of the molar ratio (M 1 / M 2 ) and easily adjusts the crystallite size to a desired value, the concentration is preferably 0.0001 mol / L or more, more preferably 0.0003 mol / L or more, and even more preferably 0.001 mol / L or more. 1 / M 2 ) and easily adjust the crystallite size to a desired value, the concentration is preferably 0.5 mol / L or less, more preferably 0.4 mol / L or less, and even more preferably 0.3 mol / L or less.

[0042] In one embodiment of the method for producing a metal complex according to the present invention, (ii) the metal (M 2 ) to the metal cation (M 1 ) molar ratio (M 1 / M 2 ) is less than 1.0, and the metal cation (M 1 In this specification, this embodiment is also referred to as a "second embodiment."

[0043] The second embodiment is similar to the first embodiment except as otherwise noted. Except for descriptions explicitly referring to the first and second embodiments, the descriptions in this specification are applicable to both embodiments.

[0044] In the second embodiment, a metal (M 2 ) to the metal cation (M 1 ) molar ratio (M 1 / M 2) is preferably 0.9 or less, and the molar ratio (M 1 / M 2 ) and easily adjusts the crystallite size to a desired value, it is more preferably 0.3 or less, and even more preferably 0.2 or less.

[0045] In a second embodiment, a metal cation (M 1 The concentration of the metal salt in the solution containing the metal salt is determined by the molar ratio (M 1 / M 2 ) and easily adjusts the crystallite size to a desired value, the concentration is preferably 0.0001 mol / L or more, more preferably 0.0003 mol / L or more, and even more preferably 0.001 mol / L or more. 1 / M 2 ) and easily adjust the crystallite size to the desired value, the concentration is preferably 0.05 mol / L or less, more preferably 0.02 mol / L or less, and even more preferably 0.01 mol / L or less.

[0046] In the method for producing a metal complex according to the present invention, a metal cation (M 1 The temperature at which the solution containing the metal cyano complex is mixed with the solution containing the metal cyano complex is preferably −5° C. or higher, more preferably 0° C. or higher, and even more preferably 5° C. or higher. The temperature is preferably 180° C. or lower, more preferably 150° C. or lower, and even more preferably 100° C. or lower.

[0047] In both the first and second embodiments of the method for producing a metal complex according to the present invention, the mixing time is not particularly limited, but is preferably 5 minutes or more, more preferably 10 minutes or more, and even more preferably 30 minutes or more. The mixing time is preferably 30 hours or less, more preferably 10 hours or less, and even more preferably 5 hours or less.

[0048] In both the first and second embodiments of the method for producing a metal complex according to the present invention, filtration, washing, drying, etc. may be performed after the mixing, as necessary. The methods for filtration, washing, drying, etc. are not particularly limited, and known methods (such as centrifugation) can be used. In one embodiment, the product obtained after the mixing can be used as a dispersion liquid as is.

[0049] Furthermore, in both the first and second embodiments, the method for producing a metal complex according to the present invention can be carried out under atmospheric conditions (1 atm, oxygen concentration of approximately 21%). Therefore, there is no need to adjust the atmosphere to an inert gas atmosphere, a hydrogen gas atmosphere, or the like during mixing. Operations such as reducing pressure or increasing pressure are also not required during mixing.

[0050] Furthermore, in both the first and second embodiments, unlike conventional techniques that use surfactants to suppress particle growth, the method for producing a metal complex according to the present invention does not require the use of other additives such as surfactants (nonionic surfactants, etc.). Therefore, one preferred embodiment includes a method for producing a metal complex without using surfactants. Another preferred embodiment includes a method for producing a metal complex without using monovalent metal cations (M 1 and a solution containing a metal cyano complex, and the solution containing the metal cyano complex is used as raw materials only, and the method satisfies the above condition (i) or (ii).

[0051] Furthermore, in the method for producing a metal complex according to the present invention, the raw materials react in a solution, the target substance is produced uniformly, and the metal complex can be produced as nanoparticles with a uniform particle size.

[0052] The metal complex according to the present invention can be used in combination with other substances as necessary for applications such as automobile parts, electric parts and electronic parts (heat dissipation substrates, discharge conversion elements, ECU electronic circuits, in-vehicle electronic circuit devices, display devices (smartphones and the like)), packaging materials, semiconductor manufacturing equipment, large astronomical telescopes, railroad tracks, artificial satellites, building materials (for example, housing parts (wall materials, roofing materials, etc. including heat insulating materials), cement, etc.), battery materials (electrodes, ion sensor materials, electrolytes, heat-insulating buffer materials, etc.), dental materials, medical materials, paints (coloring materials, etc.), magnetic materials, radiation substance absorbers, sensor materials, sound-insulating materials, sound-absorbing materials, etc.

[0053] The metal complex according to the present invention can be suitably used as a semiconductor material (specifically, an interposer for a semiconductor package, an encapsulant for a semiconductor package) among the aforementioned automotive parts, electrical parts, and electronic parts. In semiconductor packages, IC chips are increasingly being mounted at higher densities to improve processing speed. One or more semiconductor chips (IC chips) are mounted on a substrate via an interposer, and information is transmitted via the interposer. Therefore, connection reliability is important for interposers used in semiconductor packages. Heat generated during IC chip operation causes materials in the semiconductor package to expand. When materials with different coefficients of thermal expansion (CTEs) are bonded together (dissimilar materials), thermal expansion can cause numerous problems, including cracking of the IC chip, warping, peeling at the connection between the IC chip and the package substrate, and poor connection between the package substrate and the motherboard. Therefore, it is extremely important to develop an interposer for semiconductor packages that can suppress warping and peeling at the connection when temperatures change during manufacturing and use, including heating and cooling, and that has high connection reliability. Conventionally, materials consisting of a laminate of a thin resin sheet layer and a thick silicon or glass layer have been used, but these materials do not fundamentally suppress volumetric changes upon temperature changes. Even if the resin sheet layer, silicon layer, or glass layer were replaced with a different material, they did not fundamentally suppress volumetric changes upon temperature changes. In contrast, the metal complex of the present invention can suppress volumetric changes upon temperature changes during manufacturing and use, thereby suppressing warping and peeling due to thermal expansion, thereby providing an interposer for semiconductor packages with high connection reliability. In particular, prior art technologies have resulted in a difference in CTE between the resin sheet layer and the IC chip. Therefore, for example, the metal complex of the present invention can be used as a filler material to adjust the CTE of the resin sheet layer or suppress expansion upon temperature changes. The metal complex of the present invention can slow the anisotropic expansion and contraction of atoms, thereby making the CTE negative along a predetermined axis.Therefore, by lowering the CTE of the resin sheet layer, the difference with the CTE of the IC chip can be further narrowed. For example, in conventional technology in which a material consisting of a laminate including a resin sheet layer containing a glass filler is used as an interposer for a semiconductor package, by replacing the glass filler with the metal complex or composite thereof according to the present invention, the CTE of the resin sheet layer can be lowered, as described above, thereby providing an interposer for a semiconductor package with high connection reliability, in which the difference with the CTE of the IC chip can be further narrowed. Furthermore, in applications as an interposer for a semiconductor package, by aligning and orienting the crystal axes of the crystallites of the metal complex according to the present invention, an interposer for a semiconductor package in which expansion in the substrate plane direction is desired to be suppressed can be provided. In another embodiment, by using the metal complex according to the present invention as the interposer for a semiconductor package itself, warping due to thermal expansion can be suppressed, peeling can also be suppressed, and an interposer for a semiconductor package with high connection reliability can be provided. This eliminates the need for laminating glass plates in the interposer for a semiconductor package, thereby reducing costs and further enhancing the advantage of miniaturization, which is industrially advantageous. Furthermore, when an interposer is enlarged, heat tends to concentrate because signals are transmitted between multiple IC chips, which causes differences in the degree of thermal expansion and puts stress on the interposer itself, and in conventional technologies, there have been cases where the type of material used for the interposer made it impossible to enlarge the interposer. In contrast, the metal complex of the present invention is advantageous in that it can suppress volume changes when the temperature changes, eliminating the need to consider differences in the degree of thermal expansion and preventing thermal management problems when the interposer is enlarged. Furthermore, since the metal complex of the present invention can suppress the occurrence of warping, cracking, and peeling caused by differences in CTE due to thermal expansion, it can also be suitably used in semiconductor package encapsulants and printed wiring boards (PCBs).

[0054] In one embodiment, in consideration of applications as an electronic component material, from the viewpoint of being able to effectively suppress expansion due to temperature changes, a composite including the metal complex and a carrier, the carrier including at least one selected from the group consisting of a phenolic resin, a polyimide resin, and an epoxy resin is mentioned. In another embodiment, in consideration of applications as a cement, from the viewpoint of being able to effectively suppress cracks due to temperature changes, a composite including the metal complex and a carrier, the carrier including tricalcium silicate [(CaO)3(SiO2)], dicalcium silicate [(CaO)2(SiO2)], tricalcium aluminate [(CaO)3(Al2O3)], and tetracalcium aluminoferrate [(CaO)4(Al2O3)(Fe2O3)] is mentioned. Another embodiment, taking into consideration the application of electronic circuits from the viewpoint of effectively suppressing expansion due to temperature changes, includes a composite comprising the metal complex and a carrier, wherein the carrier contains a solder alloy (e.g., a solder alloy having an alloy composition consisting of, by mass%, 3.0 to 3.8% Ag, 0.1 to 1.0% Cu, 1.1% to less than 1.5% Bi, 1.0 to 7.9% Sb, 0.020 to 0.040% Fe, 0.001 to 0.008% Co, and the remainder Sn, as described in Japanese Patent No. 7323854). In this embodiment, by combining a solder alloy having excellent thermal conductivity with the metal complex of the present invention, which has an excellent effect of suppressing volume change due to heat, it is possible to provide electronic circuit components that have excellent thermal conductivity, excellent heat resistance, and excellent long-term stability. As described above, by combining the metal complex of the present invention with a carrier having other properties, it is possible to provide a highly safe material that has excellent heat resistance and can suppress the occurrence of cracks and the like over the long term.

[0055] Another embodiment includes a method for improving the suppression of volume change when the temperature of the metal complex changes by providing a temperature history of heating and cooling to the metal complex according to the present invention. The temperature at which the temperature rise starts during heating is not particularly limited and may be, for example, −250°C, −190°C, −100°C, or 0°C. The temperature rise rate during heating and the temperature drop rate during cooling are not particularly limited and may be set to, for example, 0.1°C / min or more, 1°C / min or more, or 5°C / min or more. The target temperature to be reached during heating is not particularly limited and may be, for example, 50°C, 80°C, 100°C, 150°C, 170°C, 180°C, 200°C, or 300°C. The temperature drop start temperature during cooling is not particularly limited and may be set to, for example, the target temperature to be reached during heating described above. The target temperature to be reached during cooling is not particularly limited and may be set to, for example, the temperature rise start temperature described above. The number of times the temperature history of temperature increase and decrease is given is not particularly limited, and may be one time, or may be repeated two or more times from the viewpoint of further improving the ability of the metal complex to suppress volume change when the temperature changes.

[0056] The present invention includes embodiments in which all or part of the above-described configurations are combined in various ways within the scope of the technical concept of the present invention, as long as the effects of the present invention are achieved.

[0057] The present invention will now be described in more detail with reference to examples. However, these examples are not intended to limit the scope of the present invention, and numerous modifications within the scope of the present invention are possible by those skilled in the art. In the following, room temperature refers to 25°C. In the following examples and comparative examples, the heating and cooling rates for X-ray diffraction measurements were set to 5°C / min. For accurate measurements, a temperature stabilization time of 5 to 10 minutes was allowed after reaching the set temperature (sampling temperature). Furthermore, approximately 7 minutes were allowed for height adjustment before each measurement, after which sampling was performed. "Height adjustment" refers to adjusting the sample position (sample height) during measurement to ensure more accurate measurements, taking into account the possibility that the height of the sample surface may change due to volumetric changes.

[0058] [Measurement of Crystallite Diameter of Metal Complex] For the metal complexes obtained in the Examples and Comparative Examples, an X-ray diffraction spectrum was obtained using an X-ray diffractometer (RINT2500, manufactured by Rigaku). The measurement conditions were as follows. <Measurement Conditions> Measurement device: X-ray diffractometer (RINT2500, manufactured by Rigaku) ​​Radiation source: MoKα1 radiation source (λ=0.7093 Å) Sampling interval: 0.002° Scan rate: 2θ=0.2° / min 2θ measurement range: 4 to 20° Temperature range: 90 to 450 K Divergence slit (DS): 1° Divergence vertical limiting slit: 5 mm Scattering slit (SS): 1° Receiving slit (RS): 0.3 mm Monochrome receiving slit: 0.8 mm Tube voltage: 50 kV Tube current: 300 mA However, for Example 5, some of the measurement conditions were changed as follows. Temperature range: 80 to 450 K For Examples 6 and 7, some of the measurement conditions were changed as follows: Radiation source: CuKα radiation source (λ=1.5418 Å) Scan rate: 2θ=1.0° / min 2θ measurement range: 10 to 44.5° Temperature range: 300 to 450 K (300 to 500 K in Example 7)

[0059] Thereafter, the full width at half maximum (FWHM) of the peaks indexed to the obtained 101 plane and 001 plane was calculated by fitting analysis, and the obtained FWHM value was applied to the Scherrer equation to determine the crystallite size. Two crystallite sizes were calculated from each of the two values. In all measurement results, the crystallite size calculated from the 101 plane was smaller than the crystallite size calculated from the 001 plane. Hereinafter, the crystallite size calculated from the 101 plane is shown unless otherwise stated.

[0060] [Measurement of Changes in Lattice Constant and Unit Cell Volume of Metal Complex] X-ray diffraction measurements performed under the above conditions obtained the lattice constants a and c of the a-axis and c-axis of the crystal at each sampling temperature, and evaluated the extent to which the a-axis and c-axis of the crystal changed with temperature. Furthermore, the unit cell dimensions a, b, and c and angles α, β, and γ were determined by X-ray diffraction measurements, and the volume was calculated from these values. Specifically, analysis of the XRD profile obtained by X-ray diffraction measurements confirmed that the synthesized crystal sample belonged to a trigonal crystal system. Furthermore, the lengths a, b, and c were determined by analysis, and it was determined that γ was 60° and α and β were 90°. Therefore, the unit cell volume V was calculated using a general equation for calculating volume. Specifically, since the crystal system was trigonal, the unit cell had the shape of a rhomboidal prism (a square prism with a rhomboidal base), and the volume of the rhomboidal prism was calculated.

[0061] [Calculation of the Average Thermal Expansion Coefficient of a Metal Complex] Using the lattice constants and unit lattice volumes obtained as described above, the average thermal expansion coefficient α for a predetermined temperature range is calculated from the following formula: a , α c and α v (Unit: 10 -6 K -1 ) was calculated. α = (1 / L) (dL / dT) (wherein, α a , and α c In the calculation of α, L represents the lattice constant a or c, dL represents the change in the lattice constant a or c, and dT represents the change in temperature. v In the calculation of (a), L represents the unit cell volume V, dL represents the change in the unit cell volume V, and dT represents the change in temperature.

[0062] Example 1: A K3[Co(CN)6] aqueous solution containing 0.87 mol / L of K3[Co(CN)6] was added to an AgNO3 aqueous solution containing 0.1 mol / L of AgNO3 at a molar ratio of 3. The mixture was stirred at room temperature for 1 hour to precipitate microcrystals of a Prussian blue analog (Ag3[Co(CN)6]). The water-insoluble Prussian blue analog microcrystals were separated by centrifugation, washed three times with water, then twice with methanol, and dried under reduced pressure. The crystallite diameter of the resulting Ag3[Co(CN)6] crystals was measured using the method described above and found to be 21.2 nm. The results of SEM observation of the crystals are shown in Figure 1B, and the results of powder X-ray diffractometry analysis of the crystals are shown in Figure 2. In Figure 2, the results of Example 1 are indicated by a "△" (△).

[0063] Example 2 Ag3[Co(CN)6] was produced in the same manner as in Example 1, except that the concentration of AgNO3 was changed to 0.01 mol / L. The crystallite size of the resulting Ag3[Co(CN)6] crystals was measured using the method described above, and was found to be 15.6 nm. The results of SEM observation of the crystals are shown in Figure 1C, and the results of powder X-ray diffraction analysis of the crystals are shown in Figure 2. In Figure 2, the results of Example 2 are indicated by "◯".

[0064] Comparative Example 1 Ag3[Co(CN)6] was produced in the same manner as in Example 1, except that the Ag / Co ratio (molar ratio) was 1.0 and the AgNO3 concentration was 1 mol / L. Figure 1A shows the results of SEM observation of the obtained Ag3[Co(CN)6] crystals, and Figure 2 shows the results of powder X-ray diffraction analysis of the crystals. In Figure 2, the results of Comparative Example 1 are indicated by "▽". As shown in Figure 1A, bulk crystals were obtained, and the desired nano-sized crystals were not.

[0065] As shown in Figure 2, compared to bulk Prussian blue analogues whose volume changes significantly with temperature changes, the nano-sized Prussian blue analogues (Examples 1 and 2) with a predetermined crystallite size were able to suppress volume changes when the temperature was changed.

[0066] Example 3 Ag3[Co(CN)6] was produced in the same manner as in Example 1, except that the Ag / Co ratio (molar ratio) was 10, the temperature during mixing was 0°C, the AgNO3 concentration was 0.1 mol / L, and the K3[Co(CN)6] concentration was changed to an aqueous solution of 0.01 mol / L. The crystallite diameter of the obtained Ag3[Co(CN)6] crystals was measured by the method described above and found to be 9.5 nm.

[0067] The crystal was heated from a state where it had never been heated (immediately after synthesis, before heat treatment) to a temperature change from 90 K to 450 K (heating rate: 5° C. / min). The results of measuring the change in the lattice constant and the change in the unit lattice volume of the metal complex at each temperature in the initial heating region shown in FIG. 4 are shown in FIG. 3A. The average thermal expansion coefficient α a , α c and α v (Unit: 10 -6 K -1) are shown in Figure 3B. In Figure 3A, "plate" means that measurement was performed using a powder X-ray diffraction measurement method in which a sample was placed on a plate-shaped substrate (sample holder), and "capillary" means that measurement was performed using a powder X-ray diffraction measurement method in which a sample was sealed in a thin tube called a capillary. In principle, it was determined that there would be no difference in the measurement results regardless of the method used. In Figure 3A, the upper row shows the results of evaluating the temperature dependence of the lattice constant, which evaluates how much the a-axis and c-axis of the crystal axes change with temperature, and the lower row shows the results of evaluating the temperature dependence of the unit cell volume, which evaluates how much the volume calculated taking into account all of the a-axis, b-axis, and c-axis changes with temperature. Following the above heat treatment, the temperature was lowered from 450 K to 90 K and then raised again to 400 K (both temperature lowering rate and temperature rising rate: 5°C / min). Specifically, the heat treatment was performed immediately after synthesis. The temperature was lowered from 300 K to 90 K, then increased from 90 K to 450 K (first temperature increase), further decreased from 450 K to 90 K, then increased from 90 K to 400 K (second temperature increase), and then decreased from 400 K to 90 K. The changes in the lattice constant and unit cell volume of the metal complex were measured at each temperature shown in FIG. 4 during the heat treatment. The measurement results are shown in FIG. 5A, and the calculated results of the thermal expansion coefficient are shown in FIG. 5B. In FIG. 5A, "△" indicates the first temperature increase from 90 K to 450 K, "▲" indicates the first temperature decrease from 450 K to 90 K, "▽" indicates the second temperature increase from 90 K to 400 K, and "▼" indicates the first temperature decrease from 400 K to 90 K. The upper row in FIG. 5B shows the measurement results when the crystal was heated from a state where it had never been heated before, and the lower row shows the measurement results when the crystal was subjected to a second heat treatment.

[0068] In the prior art, repeated heating and cooling generally causes changes in the state of the sample, such as the bonding of crystallites to each other to form larger crystals, and this reduces or eliminates the effect of suppressing volume expansion. On the other hand, from the results of Figures 5A and 5B, when focusing on the volume, the metal complex of the present invention shows that the α vIt was confirmed that the value of (I) was reduced. From this, it was confirmed that the metal complex of the present invention not only exhibits an excellent effect of inhibiting volume change, but also exhibits a uniquely excellent effect of inhibiting volume change in that the effect of inhibiting volume change is enhanced by repeated heating and cooling. Therefore, when the metal complex of the present invention is used in a product, the effect of inhibiting cracks, deformation, etc. in the product due to volume change is enhanced, and safety can be further improved, which is particularly advantageous industrially.

[0069] Example 4 Ag3[Co(CN)6] was produced in the same manner as in Example 1, except that the Ag / Co ratio (molar ratio) was 10, the mixing temperature was 0°C, the AgNO3 concentration was 0.001 mol / L, and the K3[Co(CN)6] concentration was changed to 0.0001 mol / L. The crystallite diameter of the resulting Ag3[Co(CN)6] crystals was measured using the method described above, and was found to be 10.1 nm. The crystals were heated from an unheated state from 80 K to 450 K while changing the temperature (heating rate: 5°C / min). The changes in the lattice constant and unit cell volume of the metal complex at each temperature shown in Figure 6 were measured and the results are shown in Figure 3A, and the calculated thermal expansion coefficient is shown in Figure 3B. Specifically, the temperature was lowered from 300 K to 80 K, then increased from 80 K to 450 K (first temperature increase), and then decreased from 450 K to 90 K (hereinafter, in this example, the temperature decrease rate and temperature increase rate were set to 5° C. / min). As shown in FIG. 6 , after the temperature decrease, the temperature was further increased from 90 K to 400 K (second temperature increase), and then decreased from 400 K to 90 K. The temperature was further increased from 90 K to 400 K (third temperature increase), and then decreased from 400 K to 90 K (not shown in FIG. 6 ). The lattice constant, change in unit cell volume, and expansion coefficient of the metal complex were measured at each temperature shown in FIG. 6 . The measurement results are shown in FIG. 7A , and the calculated thermal expansion coefficient is shown in FIG. 7B . In FIG. 7A , "◯" indicates the first temperature increase from 80 K to 450 K, "●" indicates the first temperature decrease from 450 K to 90 K, "△" indicates the second temperature increase from 90 K to 400 K, "▲" indicates the second temperature decrease from 400 K to 90 K, "▽" indicates the third temperature increase from 90 K to 400 K, and "▼" indicates the third temperature decrease from 400 K to 90 K. The results in FIGS. 7A and 7B confirmed that repeated temperature increases and decreases enhance the volume change suppression effect, demonstrating excellent volume change suppression effects. The metal complex of the present invention exhibits the unique effect of increasing the volume change suppression effect with repeated temperature increases and decreases.Therefore, when the metal complex of the present invention is used as a product, the effect of suppressing cracks, deformation, etc. in the product caused by volume change is enhanced, and safety can be further improved, which is particularly advantageous from an industrial perspective.

[0070] Example 5 Ag3[Co(CN)6] was produced in the same manner as in Example 1, except that the Ag / Co ratio (molar ratio) was 3, the mixing temperature was 25°C, the AgNO3 concentration was 0.1 mol / L, and the K3[Co(CN)6] concentration was changed to 0.033 mol / L. The crystallite size of the resulting Ag3[Co(CN)6] crystals was measured using the method described above, and was found to be 14 nm. The crystals were heated from an unheated state from 80 K to 450 K, and the changes in the lattice constant and unit cell volume of the metal complex were measured at each temperature shown in Figure 8. The results are shown in Figure 3A, and the calculated thermal expansion coefficient is shown in Figure 3B. Specifically, the temperature was lowered from 300 K to 80 K, then raised from 80 K to 450 K, and then lowered from 450 K to 300 K.

[0071] Example 6 Ag3[Co(CN)6] was produced in the same manner as in Example 1, except that the Ag / Co ratio (molar ratio) was 100, the mixing temperature was 0°C, the AgNO3 concentration was 0.1 mol / L, and the K3[Co(CN)6] concentration was changed to 0.001 mol / L. The crystallite diameter of the resulting Ag3[Co(CN)6] crystals was measured using the method described above, and was found to be 8.8 nm. The crystals were heated from a never-heated state from 300 K to 450 K, and the changes in the lattice constant and unit cell volume of the metal complex were measured at each temperature shown in Figure 9. The results are shown in Figure 3A, and the calculated thermal expansion coefficient is shown in Figure 3B. Specifically, the temperature was increased from 300 K to 450 K, and then decreased from 450 K to 300 K.

[0072] Comparative Example 2: In Comparative Example 2, bulk Ag3[Co(CN)6], rather than nano-sized, was produced as a known substance using the method described in Andrew L. Goodwin et al. "Colossal Positive and Negative Thermal Expansion in the Framework Material Ag3[Co(CN)6]," Science 319, 794 (2008) (hereinafter simply referred to as "Prior Art Document 1"). The volume change of the bulk Ag3[Co(CN)6] was evaluated using the same method as in Example 3. The results of measuring the change in the lattice constant and unit cell volume of the bulk Ag3[Co(CN)6] are shown in Figure 3A. Specifically, bulk Ag3[Co(CN)6] was produced using the following method. Aqueous solutions (30 mL each) of K3[Co(CN)6] (3.8154 g, Aldrich) and AgNO3 (5.0889 g, Aldrich) were slowly mixed at room temperature and stirred for 1 hour at the boiling point of the mixed solution, approximately 100 °C. This resulted in the formation of a white precipitate. After slowly cooling to room temperature, the mixture was filtered and the residue was washed with distilled water (3 × 100 mL). The resulting product was dried at 60 °C for 24 hours to obtain Ag3[Co(CN)6] as a white powder (5.1644 g, yield: 83.5%). In Figure 2, the squares indicate the results for Ag3[Co(CN)6] obtained according to the method disclosed in Prior Art Document 1. As shown in Figure 2, in the known technology according to Prior Art Document 1, indicated by "□", the volume changes significantly depending on the temperature, and the nano-sized metal complex according to the present invention cannot be produced.It can be seen that, unlike the metal complex according to the present invention, the effect of suppressing volume change during temperature change is not obtained.Furthermore, prior art document 2, R. Mittal et al., "Phonons and colossal thermal expansion behavior of AgCo(CN) and AgFe(CN)," Journal of Physics: Condensed Matter, 2012 Dec. 19; Volume 24, Number 50:505404 (DOI 10.1088 / 0953-8984 / 24 / 50 / 505404), also discloses the production of Ag[Co(CN)]. However, similar to prior art document 1, it discloses a process in which an aqueous solution of AgNO is slowly added to an aqueous solution of K[Co(CN)]. In prior art document 2, the slow mixing process also prevents the larger component from being present at the beginning of the reaction in sufficient amounts to function as a capping agent. Therefore, unlike the case of lump-sum addition, the effect of suppressing crystal growth is not fully achieved. As a result, similar to comparative example 2, a nanosized metal complex cannot be produced.

[0073] Example 7 Ag3[Co(CN)6] was produced in the same manner as in Example 1, except that the Ag / Co ratio (molar ratio) was 3, the mixing temperature was room temperature, the AgNO3 concentration was 0.01 mol / L, and the K3[Co(CN)6] concentration was changed to an aqueous solution of 0.0033 mol / L. The crystallite diameter of the obtained Ag3[Co(CN)6] crystals was measured by the method described above and was found to be 11 nm.

[0074] Example 8 Ag3[Co(CN)6] was produced in the same manner as in Example 1, except that the Ag / Co ratio (molar ratio) was 10, the mixing temperature was 30°C, the AgNO3 concentration was 0.01 mol / L, and the K3[Co(CN)6] concentration was changed to an aqueous solution of 0.001 mol / L. The crystallite diameter of the obtained Ag3[Co(CN)6] crystals was measured by the method described above and was found to be 10.1 nm.

[0075] Example 9 Ag3[Co(CN)6] was produced in the same manner as in Example 1, except that the Ag / Co ratio (molar ratio) was 3, the temperature during mixing was 0°C, the mixing and stirring time was 24 hours, the AgNO3 concentration was 0.1 mol / L, and the K3[Co(CN)6] concentration was changed to an aqueous solution of 0.033 mol / L. The crystallite diameter of the obtained Ag3[Co(CN)6] crystals was measured by the method described above and was found to be 21 nm.

[0076] Example 10 Ag[Co(CN)] was produced in the same manner as in Example 9, except that the mixing and stirring time was changed to 1.5 hours. The crystallite diameter of the obtained Ag[Co(CN)] crystals was measured by the method described above and found to be 16.1 nm.

[0077] Example 11 Ag[Co(CN)] was produced in the same manner as in Example 9, except that the mixing and stirring time was changed to 0.5 hours. The crystallite size of the obtained Ag[Co(CN)] crystals was measured by the method described above and found to be 17 nm.

[0078] Example 12 Ag3[Co(CN)6] was produced in the same manner as in Example 1, except that the Ag / Co ratio (molar ratio) was 3, the temperature during mixing was 0°C, the AgNO3 concentration was 0.01 mol / L, and the K3[Co(CN)6] concentration was changed to an aqueous solution of 0.0033 mol / L. The crystallite diameter of the obtained Ag3[Co(CN)6] crystals was measured by the method described above and was found to be 13 nm.

[0079] Example 13 Ag3[Co(CN)6] was produced in the same manner as in Example 1, except that the Ag / Co ratio (molar ratio) was 3, the mixing temperature was 100°C, the AgNO3 concentration was 0.1 mol / L, and the K3[Co(CN)6] concentration was changed to an aqueous solution of 0.033 mol / L. The crystallite diameter of the obtained Ag3[Co(CN)6] crystals was measured by the method described above and was found to be 23 nm.

[0080] Example 14 Ag3[Co(CN)6] was produced in the same manner as in Example 1, except that the Ag / Co ratio (molar ratio) was 0.1, the temperature during mixing was 0°C, the AgNO3 concentration was 0.01 mol / L, and the K3[Co(CN)6] concentration was changed to an aqueous solution of 0.1 mol / L. The crystallite diameter of the obtained Ag3[Co(CN)6] crystals was measured by the method described above and was found to be 26 nm.

[0081] Example 15: A K3[Fe(CN)6] aqueous solution containing 1 mmol / L of K3[Fe(CN)6] was added to an AgNO3 aqueous solution containing 0.1 mol / L of AgNO3 at a molar ratio of 100 (100 / 1), and the mixture was stirred at room temperature for 1 hour to precipitate microcrystals of a Prussian blue analog (Ag3[Fe(CN)6]). The water-insoluble Prussian blue analog microcrystals were separated by centrifugation, washed three times with water, then twice with methanol, and dried at 55°C for 24 hours. The crystallite size of the resulting Ag3[Fe(CN)6] metal complex was measured using a MoKα X-ray source at the same temperature range as in Example 1. The full width at half maximum (FWHM) of the peak indexed to the obtained 001 plane was calculated by fitting analysis, and the obtained FWHM value was applied to the Scherrer equation to determine the crystallite diameter, which was 12.3±1.2 nm. Furthermore, the obtained Ag3[Fe(CN)6] was measured using the above-mentioned method for measuring the lattice constant of a metal complex under the same measurement temperature range as in Example 1 (90 to 450 K). However, since the peak intensity in the temperature range above 300 K was weak, the average thermal expansion coefficient α was calculated using the lattice constants a and c in the range of 90 to 300 K. a , and α c (Unit: 10 -6 K -1 ) was calculated. a is 36±5, and α c was −39±6.

[0082] Comparative Example 3 According to Prior Art Document 2, Ag3[Fe(CN)6] was produced by the following procedure. Specifically, an AgNO3 aqueous solution with an AgNO3 concentration of 1 mol / L was slowly added to a K3[Fe(CN)6] aqueous solution with a K3[Fe(CN)6] concentration of 0.33 mol / L at room temperature so that the Ag / Fe ratio (molar ratio) was 3 (3 / 1). The mixed solution was stirred at room temperature for 2 hours to obtain a deep orange-red precipitate. Ag3[Fe(CN)6] was separated by centrifugation, washed three times with water, then twice with methanol, and dried at 50°C for 5 hours. According to Prior Art Document 2, the average thermal expansion coefficient α a , and α c (Unit: 10 -6 K -1 ) is calculated, and α a is 124.0±10, and α c was −113±3. In comparison with Example 15, α a In Example 15, the value was less than one-third of that in Prior Art Document 2, and c In Example 15, the volume change was one-third of that in Prior Art Document 2, and it was confirmed that the metal complex of the present invention has significantly more advantageous performance than Prior Art Document 2 in terms of suppressing volume change.

[0083] Example 16: First, a 1.27 mol / L NaHSO solution was prepared in a water bath, and a 1.27 mol / L CuSO.5H.sub.2O solution was added in one portion and stirred for 30 minutes to obtain a mixed solution. A 0.126 mol / L K[Co(CN)] solution was added in one portion to the mixed solution so that the Cu / Co molar ratio was 10 (10 / 1). The mixture was stirred at room temperature for 1 hour to precipitate microcrystals of a Prussian blue analog (Cu[Co(CN)]). The water-insoluble Prussian blue analog microcrystals were separated by centrifugation, washed three times with water, then twice with methanol, and dried for 24 hours. The crystallite diameter of the obtained Cu3[Co(CN)6] was measured under the same temperature range as in Example 1, using a MoKα1 X-ray source. The full width at half maximum (FWHM) of the peak indexed to the obtained 001 plane was calculated by fitting analysis, and the obtained FWHM value was applied to the Scherrer equation to determine the crystallite diameter, which was 41±2 nm. Furthermore, the obtained Cu3[Co(CN)6] was measured in the range of 90 to 450 K using the method for measuring the lattice constant of a metal complex described above, as in the examples, and the average thermal expansion coefficient α was calculated using the lattice constant a and the lattice constant c. a , and α c (Unit: 10 -6 K -1 ) was calculated. a is 23.2, and α c was -46.4.

[0084] The metal complex of the present invention can suppress volume expansion due to temperature changes, and can suppress cracks and deformation. Furthermore, it has the unique effect of increasing the effect of suppressing volume changes with repeated temperature increases and decreases. Therefore, when used in situations where temperature changes are repeated, the effect of suppressing volume changes is further increased, thereby further increasing safety, making it particularly useful industrially.

Claims

1. A metal complex having a crystallite size of 60 nm or less and represented by the following general formula (1): (M 1 ) p [(M 2 ) q (CN)6]・nH2O (1) (wherein, M 1 represents at least one selected from the group consisting of Ag(I), Au(I), and Cu(I); M 2 represents at least one trivalent transition metal, p is a positive number of 2.5 or more and 3.5 or less, q is a positive number of 0.5 or more and 1.5 or less, p+q is 3.5 or more and 4.5 or less, and n is 0 or a positive number.

2. M 2 2. The metal complex according to claim 1, wherein the transition metal constituting the metal complex is at least one selected from the group consisting of Ti, V, Cr, Mn, Fe, Co, Rh, and Ir.

3. M 2 The metal complex according to claim 1 or 2, wherein the transition metal constituting the metal complex is Co.

4. M 1 3. The metal complex according to claim 1, wherein is Ag(I).

5. M 1 3. The metal complex according to claim 1, wherein is Cu(I).

6. M 2 The metal complex according to claim 1 or 2, wherein is Fe.

7. The metal complex according to claim 1 or 2, wherein p is 3 and q is 1.

8. The metal complex according to claim 1 or 2, wherein the crystallite size is 40 nm or less.

9. A composite comprising the metal complex according to claim 1 or 2 and a support.

10. Monovalent metal cations (M 1 A solution containing the metal cation (M) is mixed with a solution containing a metal cyano complex, 1 ) is at least one selected from the group consisting of Ag(I), Au(I), and Cu(I), and the solution containing the metal cyano complex contains at least one transition metal (M 2 ), (i) the transition metal (M 2 ) to the metal cation (M 1 ) molar ratio (M 1 / M 2 (ii) the transition metal (M 2 ) to the metal cation (M 1 ) molar ratio (M 1 / M 2 ) is less than 1.0, and the metal cation (M 1 3. The method for producing a metal complex according to claim 1, wherein the concentration of the metal salt in the solution containing the metal salt is 0.0001 to 0.1 mol / L.

11. The monovalent metal cation (M 1 The method for producing a metal complex according to claim 10, wherein the solution containing the metal cyano complex is mixed with the solution containing the metal cyano complex by adding them all at once.

12. The bulk addition of the metal cation (M 1 The method for producing a metal complex according to claim 11, which comprises adding a solution containing a metal cyano complex to a solution containing a metal cyano complex.

13. The transition metal (M 2 11. The method for producing a metal complex according to claim 10, wherein the metal complex is at least one selected from the group consisting of Ti, V, Cr, Mn, Fe, Co, Rh, and Ir.

14. The method for producing the metal complex according to claim 10, which does not use a surfactant.

15. The transition metal (M 2 ) to the metal cation (M 1 ) molar ratio (M 1 / M 2 12. The method for producing a metal complex according to claim 11, wherein Mn is greater than 2.

6.

16. The metal cation (M 1 11. The method for producing a metal complex according to claim 10, wherein the temperature during mixing of the solution containing the metal cyano complex with the solution containing the metal cyano complex is −5 to 180° C.

17. The metal cation (M 1 11. The method for producing a metal complex according to claim 10, wherein said compound is Ag(I).

18. The transition metal (M 2 11. The method for producing a metal complex according to claim 10, wherein the transition metal constituting the transition metal is Co.

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