JP2016037405A - Method for manufacturing chiral metal compound structure and metal compound structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a novel metal compound structure having a metal element having chirality, and catalytic activity and fluorescent emission property.SOLUTION: A method for manufacturing a chiral metal compound structure including: a crystal producing process of reacting a polymer having a linear polyethyleneimine skeleton and a chiral dicarboxylic acid compound to obtain a chiral super molecule crystal of an acid basic type complex; a sol-gel process of effecting a hydrolyzable metal compound to the chiral super molecule crystal to form a coat layer containing a first metal compound; a reactant forming process of effecting a salt of a second metal to the chiral super molecule crystal processed through the gel-sol process to form a reactant between the polyethyleneimine skeleton, the dicarboxylic compound and the second metal; and a burning process of burning the chiral super molecule crystal processed through the reactant forming process to obtain a structure consisting of the coat layer, the second metal or oxide thereof.SELECTED DRAWING: Figure 8

Description

  The present invention relates to a method for producing a chiral metal compound structure and a metal compound structure.

  In recent years, nanostructures with specific spatial shapes and regular structures in the order of nanometers, which are obtained by self-organizing organic compounds in an equilibrium or non-equilibrium state by intermolecular interactions, have been actively proposed. . These nanostructures can be used not only as a base for constructing organic / inorganic composite nanomaterials of various compositions, but also as templates for forming nanostructures made of various materials. Therefore, it is attracting interest from interdisciplinary fields and industrial fields.

  As an example of such a nanostructure, for example, in Patent Document 1, a surfactant having a specific chemical structure is self-assembled in a solution, and a compound serving as a silica source is subjected to a sol-gel reaction around the surface to form a mesoporous material. It has been proposed to form silica particles. In Patent Document 2, a micro phase separation structure is formed from two types of water-insoluble and water-insoluble polymers that are incompatible with each other, and based on this, pores having a cylinder structure with an average pore diameter of 1 to 200 nm are disclosed. It has been proposed to form a porous membrane comprising It is also well known that biopolymers such as DNA and proteins become nanostructures with a unique three-dimensional structure by self-organization. However, few crystalline nanostructures are made of polymers with crystallinity.

  Further, it has been proposed to transfer a chirality of a template to a metal oxide by using a nanostructure having chirality as a template and growing a metal oxide layer such as silica around the nanostructure. As an example, Patent Document 3 discloses that a polymer having an optically active chiral alignment structure such as a helical structure is used as a template, and a metal source is allowed to act on the template to obtain a chiral organic / inorganic composite. Has been proposed. In such an organic / inorganic composite, the chirality is transferred to the metal oxide. For example, if a metal oxide having catalytic activity is selected as the inorganic component of the organic / inorganic composite, a chiral reaction is performed. It is considered that a metal oxide catalyst having a field may be obtained.

  On the other hand, it has also been proposed to obtain an optical functional material exhibiting circularly polarized light by combining a compound exhibiting light emission with a compound having chirality by means such as complex formation. As an example of such a material, Non-Patent Document 1 reports that fluorescence emitted from a rare earth complex changes from noncircularly polarized light emission to circularly polarized light emission by binding a chiral compound to the rare earth complex. Yes. Non-Patent Document 2 reports that circularly polarized light emission was observed in a supramolecular solid complex of thiophene, which is a compound exhibiting fluorescence, and chiral (R) -1- (2-naphthyl) ethylamine. Has been. Patent Document 4 reports that a seven-coordinate rare earth complex having a chiral ligand exhibits circularly polarized light emission.

  Circularly polarized light emission is a light emission phenomenon that generates circularly polarized light whose vibration surface rotates as the wave of light travels. Such circularly polarized light includes clockwise circularly polarized light and counterclockwise circularly polarized light. In a familiar example, bioluminescence represented by firefly light is assumed to have circular polarization. Such a material exhibiting circularly polarized light is expected to be applied to a three-dimensional display, as a raw material for security markers and invisible ink.

JP 2010-208907 A JP 2009-256592 A JP 2005-239863 A JP2013-121921A

Iwamura, M .; et al. Inorg. Chem. 2012, 51, 4094-4098 Kimoto, T .; et al. , Tetrahedron 2011, 67, 7775-7779.

  As described above, metal compounds and luminescent compounds having chiral properties are promising as catalysts or circularly polarized light-emitting materials that provide chiral reaction fields. The present invention has been made in view of the above situation, and an object thereof is to provide a novel metal compound structure having a metallic element having chiral properties and having catalytic activity and fluorescence. To do.

  The present inventors diligently studied as follows in order to solve the above problems. First, using a supramolecular crystal of an acid-base complex obtained by reacting a polymer having a linear polyethyleneimine skeleton and a chiral dicarboxylic acid compound, a hydrolyzable metal compound is allowed to act on the supramolecular crystal. Thus, an inorganic oxide coat layer made of a hydrolyzate of the metal compound was formed. Supramolecular crystal chirality is transferred to this coating layer, and the resulting structure is entirely composed of organic molecular supramolecular crystal chirality and an inorganic oxide (that is, a hydrolyzate of the above metal compound). There is a double chiral structure consisting of the chirality of the coating layer. Then, when a transition metal, rare earth element or noble metal salt is allowed to act on the supramolecular crystal portion, the metal ion contained in the salt is bonded to the chiral dicarboxylic acid compound, and the structure is a double chiral structure. It is converted into a metal ion trapped inside. When this is fired, the metal ions trapped in the double chiral structure become transition metal or rare earth oxides or noble metal nanoparticles, and the structure is converted into a metal compound structure having chirality. The present inventors have found and have completed the present invention. As is well known, many transition metal oxides and noble metal nanoparticles exhibit catalytic activity, and many rare earth oxides exhibit fluorescence, so that such metal compound structures have chiral reaction fields and circularly polarized light. It is promising as a luminescent material. More specifically, the present invention provides the following.

  (1) The present invention includes a crystal formation step of obtaining a chiral supramolecular crystal of an acid-base complex by reacting a polymer having a linear polyethyleneimine skeleton and a chiral dicarboxylic acid compound, and adding water to the chiral supramolecular crystal. A sol-gel process in which a coat layer containing a first metal compound that is a hydrolyzate of the metal compound is formed on the surface of the chiral supramolecular crystal by a sol-gel method in which a decomposable metal compound is allowed to act; and the sol-gel process A reactant formation step in which a salt of the second metal is allowed to act on the passed chiral supramolecular crystal to form a reactant between the polyethyleneimine skeleton and the dicarboxylic acid compound and the second metal, and the reactant By firing the chiral supramolecular crystal that has undergone the formation process, the chiral supramolecular crystal that is an organic substance is decomposed, and the coating layer and the second metal or acid thereof are decomposed. A firing step to obtain a structure comprising from the object, a method for producing a chiral metal compound structure with a.

  (2) Moreover, this invention is a manufacturing method of the chiral metal compound structure as described in the (1) term whose said dicarboxylic acid compound is tartaric acid.

  (3) Moreover, this invention is a manufacturing method of the chiral metal compound structure as described in the (1) term or (2) term whose said hydrolyzable metal compound is alkoxysilane.

  (4) The present invention further includes an aryl carboxylic acid treatment step in which an aryl carboxylic acid compound is allowed to act on the structure obtained through the baking step, and any one of items (1) to (3) 2. A method for producing a chiral metal compound structure according to item 1.

  (5) In the invention, any one of (1) to (4), wherein the second metal is a rare earth element, and the obtained chiral metal compound structure exhibits circularly polarized light emission. A method for producing a metal compound structure according to claim 1.

  (6) Moreover, this invention is a metal compound structure in which the 2nd metal or its oxide is contained inside the coating layer which is a 1st metal oxide, Comprising: Said 2nd metal or its oxide Is formed by firing a reaction product of a metal element constituting the second metal or its oxide and a chiral dicarboxylic acid compound inside the coat layer, and the second metal. Alternatively, the metal compound structure is characterized by exhibiting circular dichroism induced by the chirality of the dicarboxylic acid compound in an absorption wavelength region of the oxide.

  (7) Further, the present invention provides the metal compound structure according to item (6), wherein the first metal oxide is a silicon oxide compound derived from a hydrolyzate of alkoxysilane.

  (8) The present invention further provides the metal compound structure according to the item (6) or (7), further comprising an arylcarboxylic acid compound.

  (9) In the present invention, the metal element constituting the oxide of the second metal is a rare earth element, and circularly polarized light is emitted when irradiated with light having an absorption wavelength of the oxide of the metal or the arylcarboxylic acid. The metal compound structure according to any one of items (6) to (8), wherein

  ADVANTAGE OF THE INVENTION According to this invention, the novel metal oxide structure which has a chiral property and has a metal element provided with catalytic activity and fluorescence emission property is provided.

FIG. 1 is a solid circular dichroism spectrum of SiO ₂ @ LPEI / Tart-L and SiO ₂ @ LPEI / Tart-D. FIG. 2 shows solid circular dichroism spectra of Eu ₂ O ₃ @SiO ₂ -L and Eu ₂ O ₃ @SiO ₂ -D obtained in Example 1. 3 is a solid circular dichroism spectrum of Y ₂ O ₃ @SiO ₂ -L and Y ₂ O ₃ @SiO ₂ -D obtained in Example 2. FIG. 4 is a solid circular dichroism spectrum of ZnO @ SiO ₂ -L and ZnO @ SiO ₂ -D obtained in Example 3. FIG. FIG. 5 is a solid circular dichroism spectrum of Y ₂ O ₃ : Eu @ SiO ₂ -L and Y ₂ O ₃ : Eu @ SiO ₂ -D obtained in Example 4. 6 is a UV-Vis reflection spectrum of Y ₂ O ₃ : Eu @ SiO ₂ -L and Y ₂ O ₃ : Eu @ SiO ₂ -D obtained in Example 4. FIG. FIG. 7 is a solid powder fluorescence spectrum of Y ₂ O ₃ : Eu @ SiO ₂ -L and Y ₂ O ₃ : Eu @ SiO ₂ -D obtained in Example 4 when the excitation light is 251 nm. FIG. 8 is a circularly polarized light emission (CPL) spectrum of Y ₂ O ₃ : Eu @ SiO ₂ -L and Y ₂ O ₃ : Eu @ SiO ₂ -D obtained in Example 4. FIG. 9 shows solid circular dichroism spectra of BA / Y ₂ O ₃ : Eu @ SiO ₂ -L and BA / Y ₂ O ₃ : Eu @ SiO ₂ -D obtained in Example 5. FIG. 10 shows solid circular dichroism spectra of Ag @ SiO ₂ -L and Ag @ SiO ₂ -D obtained in Example 6.

  Hereinafter, one embodiment of a method for producing a chiral metal compound structure and one embodiment of a metal compound structure according to the present invention will be described. The present invention is not limited to the following embodiments and embodiments, and can be implemented with appropriate modifications within the scope of the present invention.

<Method for producing chiral metal oxide structure>
The method for producing a chiral metal compound structure according to the present invention comprises a crystal generation step of obtaining a chiral supramolecular crystal of an acid-base complex by reacting a polymer having a linear polyethyleneimine skeleton and a chiral dicarboxylic acid compound, and A coating layer containing a first metal compound that is a hydrolyzate of the metal compound is formed on the surface of the chiral supramolecular crystal by a sol-gel method in which a hydrolyzable metal compound is allowed to act on the chiral supramolecular crystal. A reaction in which a salt of a second metal is allowed to act on the chiral supramolecular crystal that has undergone the sol-gel process and the sol-gel process to form a reactant between the polyethyleneimine skeleton and the dicarboxylic acid compound and the second metal. The chiral supramolecular crystal, which is an organic substance, is decomposed by firing the chiral supramolecular crystal that has undergone the product forming step and the reactant forming step, and the Comprising a coat layer and baking to obtain a structure made of the second metal or an oxide thereof, a. When the method for producing a chiral metal compound structure according to the present invention includes the above-described steps, first, a supramolecular crystal reflecting the chirality of a chiral dicarboxylic acid compound is used as a template. The chirality is transferred to the coating layer containing the first metal formed as described above, and is composed of the chirality of the organic compound (supermolecular crystal) and the chirality of the inorganic oxide (first metallic compound). A complex having the following chiral structure is formed. Then, the chirality is transcribe | transferred to the metal compound structure containing a 2nd metal by making the salt of a 2nd metal act on this, and baking. The metal compound structure thus obtained has a structural chirality based on the arrangement of the second metal compound. If the second metal is a transition metal or a noble metal, it can be used for a catalyst having a chiral reaction field or a circular It can be used as a security application using chromaticity, etc. If the second metal is a rare earth element, it can be used as a circularly polarized light emitting material. Hereinafter, each step will be described.

[Crystal generation process]
The crystal formation step is a step of obtaining a chiral supramolecular crystal of an acid-base type complex by reacting a polymer having a linear polyethyleneimine skeleton and a chiral dicarboxylic acid compound.

  The polymer having a linear polyethyleneimine skeleton used in the present invention (hereinafter also simply referred to as “polymer”) has a structure represented by the following chemical formula in the molecule. The structure represented by the following chemical formula contains a secondary amino group, and the nitrogen atom of this amino group interacts with a carboxyl group contained in a chiral dicarboxylic acid compound described later to form an acid-base type complex. . The above chiral dicarboxylic acid compound is a dibasic acid having two carboxyl groups and can form a complex with each of the amino groups contained in the bimolecular polymer. Cross-linked by compound. As a result, an acid-base complex type supramolecular crystal having a structure in which a plurality of polymers and a plurality of chiral dicarboxylic acid compounds are self-assembled is formed. This supramolecular crystal has structural chirality induced by the chiral dicarboxylic acid compound.

（上記化学式中、ｎは１以上の整数である。）

(In the above chemical formula, n is an integer of 1 or more.)

  The polymer used in the present invention only needs to have a linear polyethyleneimine skeleton represented by the above chemical formula in the molecule, and the structure of the other parts is not particularly limited. Or a homopolymer having the above chemical formula, or a copolymer having other repeating units. When the polymer is a copolymer, it is preferable from the viewpoint that a stable crystal can be formed if the molar ratio of the linear polyethyleneimine skeleton portion in the polymer is 20% or more. A block copolymer having 10 or more units is more preferable. Most preferably, the polymer is a homopolymer having the above chemical formula.

  Moreover, as a polymer, it is so preferable that the ability to form a crystalline association with the chiral dicarboxylic acid compound mentioned later is high. Therefore, regardless of whether the polymer is a homopolymer or a copolymer, the molecular weight of the portion corresponding to the linear polyethyleneimine skeleton portion represented by the above chemical formula is in the range of about 500 to 1,000,000. It is preferable. A commercially available product may be used as the polymer having the linear polyethyleneimine skeleton, or the polymer may be obtained by a synthesis method disclosed in Japanese Patent Application Laid-Open No. 2009-30017.

  As described above, the chiral dicarboxylic acid compound used in the present invention is derived from the dicarboxylic acid compound while the two carboxyl groups of the dicarboxylic acid crosslink the above polymer to form a supramolecular crystal. The structural chirality is induced in supramolecular crystals. The dicarboxylic acid compound may be D-form or L-form. The optical purity of the dicarboxylic acid compound is not necessarily 100% ee, preferably 90% ee or more, more preferably 95% ee or more, and more preferably 98% ee or more. preferable.

  The dicarboxylic acid compound only needs to have two carboxyl groups and an asymmetric carbon, and preferably has four or more carbon atoms. In addition, the dicarboxylic acid compound may be linear or branched. Examples of such a dicarboxylic acid compound include tartaric acid, altaric acid, glucaric acid, mannaric acid, guluronic acid, idalic acid, galactaric acid, and tartalic acid, with tartaric acid being preferred.

  In this step, the above polymer and a chiral dicarboxylic acid compound are allowed to act in water to form a supramolecular crystal composed of these and water molecules. Next, an embodiment for forming such a supramolecular crystal will be described. In this aspect, the polymer aqueous solution preparation substep, the dicarboxylic acid aqueous solution preparation substep, the mixing substep, and the precipitation substep are sequentially performed. Hereinafter, these steps will be described.

  In the polymer aqueous solution preparation sub-step, an aqueous solution of a polymer having a linear polyethyleneimine skeleton is prepared. At this time, it is preferable that the water used for preparing the aqueous solution is heated to 80 ° C. or higher by heating. The polymer having a linear polyethyleneimine skeleton used at this time is as described above.

  An example of a procedure for preparing an aqueous solution of the polymer can include dissolving the polymer by adding the polymer powder to distilled water and heating it to 80 ° C. or higher. At this time, the concentration of the polymer in the aqueous solution is preferably in the range of 0.5 to 8% by mass, but is not particularly limited.

  The prepared aqueous polymer solution is subjected to a small mixing step described later while being heated.

  Although the dicarboxylic acid aqueous solution preparation substep is not particularly limited, it is preferably performed in parallel with the polymer aqueous solution preparation substep. In this small process, an aqueous solution of the aforementioned dicarboxylic acid compound is prepared. The dicarboxylic acid compound used here is chiral (optically active substance). In addition, it is preferable that the water used for preparing the aqueous solution is heated to 80 ° C. or higher by heating.

  As an example of the procedure for preparing an aqueous solution of a dicarboxylic acid compound, there can be mentioned dissolving the dicarboxylic acid compound by adding the dicarboxylic acid compound powder to distilled water and heating it to 80 ° C. or higher. At this time, the concentration of the dicarboxylic acid compound in the aqueous solution is preferably in the range of 0.5 to 15% by mass, but is not particularly limited.

  The prepared aqueous solution of the dicarboxylic acid compound is subjected to a sub-mixing step described later while being heated.

  In the small mixing step, the aqueous solution of the polymer and the aqueous solution of the dicarboxylic acid compound are mixed to obtain a mixed aqueous solution. At this time, it is preferable that the two aqueous solutions to be mixed are both heated to a temperature of about 80 ° C. or higher.

  When the aqueous solution of the polymer and the aqueous solution of the dicarboxylic acid compound are mixed, the carboxyl group contained in the dicarboxylic acid compound is 0.5 to 1 with respect to 1 equivalent of the secondary amino group contained in the linear polyethyleneimine skeleton of the polymer. It is preferably 1.5 equivalents, more preferably 0.9 to 1.1 equivalents, and even more preferably 1 equivalent.

  The mixed aqueous solution prepared in this small process is subjected to the precipitation small process.

  In the precipitation small process, an acid-base complex of the polymer and the dicarboxylic acid compound is precipitated in the mixed aqueous solution obtained in the mixing small process. As already described, this acid-base type complex is a chiral supramolecular crystal (chiral supramolecular crystal).

  In performing this small process, the heated mixed aqueous solution is gradually cooled. The cooling method at this time is not particularly limited, and as an example, a method of naturally cooling in an air atmosphere to lower the water temperature to room temperature can be mentioned. In this process, a white solid is precipitated in the aqueous solution. This powder is a porous composite formed by aggregation of nano-sized acid-base complex crystals (supermolecular crystals). In addition, when performing natural cooling as described above, the mixed aqueous solution may be left standing, or solid precipitation may be promoted by applying stirring or vibration to the aqueous solution. The white precipitate obtained is isolated by means such as filtration. The isolated precipitate may be appropriately washed with distilled water, an organic solvent such as ethanol or acetone, and dried.

  The chiral supramolecular crystal obtained in the crystal production process is subjected to a sol-gel process.

[Sol-gel process]
The sol-gel process is a hydrolyzate of the metal compound on the surface of the chiral supramolecular crystal by a sol-gel method in which a hydrolyzable metal compound is allowed to act on the chiral supramolecular crystal obtained in the crystal generation process. Forming a coating layer containing a metal compound. For convenience, the metal element contained in the hydrolyzable metal compound is referred to as the first metal. Since this metal compound is hydrolyzed to form a coat layer on the surface of the chiral supramolecular crystal, the coat layer contains the first metal compound as a hydrolyzate.

  The hydrolyzable metal compound used in this step may be any one that is hydrolyzed by reacting with water and causes a sol-gel reaction. Examples of such compounds include metal alkoxides, metal halides, and organometallic compounds. For example, when a silicon compound is used as the metal compound (that is, when silicon is selected as the first metal), the hydrolyzable metal compound includes tetramethoxysilane, trimethoxysilane, dimethoxysilane, tetraethoxysilane, triethoxysilane, Alkoxysilanes such as diethoxysilane, tetrapropoxysilane, tripropoxysilane, dipropoxysilane, tetraisopropoxysilane, triisopropoxysilane and diisopropoxysilane, halogenated silanes such as dichlorosilane and tetrachlorosilane, tetraethyl orthosilicate, etc. Can be mentioned. These metal compounds may be used alone or in combination of two or more. Moreover, when using a titanium compound as a metal compound, the water-soluble titanium lactate which causes a sol-gel reaction can be mentioned, for example. Among these metal compounds, alkoxysilane is preferably used.

In carrying out this step, the chiral supramolecular crystal obtained in the crystal generation step is subjected to a reaction with the above-described hydrolyzable metal compound (that is also a source of the first metal). The This reaction is performed by adding a hydrolyzable metal compound or a mixture of a hydrolyzable metal compound and water to a chiral supramolecular crystal dispersed in water and stirring at room temperature. In this process, the hydrolyzable metal compound causes a sol-gel reaction to form a coating layer containing a first metal compound that is a hydrolyzate of the metal compound on the surface of the chiral supramolecular crystal. Examples of the first metal compound contained in the coat layer include a polymer [(-MO-) _n ] composed of the first metal element (M) and the oxygen atom (O), and the first metal element. Includes hydroxides and the like.

  The mixing ratio of the chiral supramolecular crystal and the hydrolyzable metal compound is not particularly limited, and may be appropriately adjusted so that the coating layer is formed on almost the entire chiral supramolecular crystal. As an example of such a mixing ratio, when tetramethoxysilane is used as the hydrolyzable metal compound, 3 mL of tetramethoxysilane and 200 mL are added to 100 mL of water in which about 3 g of supramolecular crystals are dispersed. Although it is mentioned to add the mixture with water, it is not specifically limited.

  The chiral supramolecular crystal that has undergone the sol-gel process is subjected to a reactant formation process.

[Reactant formation step]
In the reaction product generation step, a salt of the second metal is allowed to act on the chiral supramolecular crystal that has undergone the sol-gel step, and the reaction between the polyethyleneimine skeleton and the dicarboxylic acid compound contained in the polymer and the second metal This is a step of forming an object.

In the above chiral supramolecular crystal, which is a complex compound of a polyethyleneimine skeleton and a dicarboxylic acid compound, a plurality of secondary amino groups and carboxyl groups are arranged almost regularly as shown in the following chemical formula, and metal ions are arranged. It is a very favorable environment for positioning. Therefore, as shown in the following chemical formula, a salt of the second metal is allowed to act on the chiral supramolecular crystal to form a complex salt between the polymer, the chiral dicarboxylic acid compound and the ion of the second metal. Thereby, it is considered that a second metal ion complex to which the chirality of the chiral dicarboxylic acid compound is transferred is formed. In this case, this second metal ion complex is a reactant in this step. The secondary amino group contained in the polyethyleneimine skeleton also has a reducing action. When a noble metal salt is used as the second metal salt, the noble metal ion is reduced, and the noble metal inside the chiral supramolecular crystal is reduced. The nanoparticles are arranged in a state where the chirality is maintained. In this case, the noble metal nanoparticles are the reactants used in this step. In addition, when a noble metal salt is used, it is a polymer having a secondary amino group that is involved in the reduction action, but before such reduction occurs, a cation between the noble metal ion and the dicarboxylic acid compound is used. An ion exchange reaction has occurred, and even in this case, the polyethyleneimine skeleton and the dicarboxylic acid compound and the second metal (noble metal ions) are still reacted. The following chemical formula schematically shows how a complex salt is formed when tartaric acid is used as the chiral dicarboxylic acid compound and M ^{n +} is used as the second metal ion.

  In addition, a complex salt was formed between the polyethylenimine skeleton and the chiral dicarboxylic acid compound and the ion of the second metal, thereby forming between the polymer having the polyethylenimine skeleton and the chiral dicarboxylic acid compound. There is a possibility that the acid-base type complex may be eliminated, but the chiral supramolecular crystal does not dissolve because the coat layer is formed around the chiral supramolecular crystal by the sol-gel process performed before this step. The shape can be maintained.

  The metal constituting the second metal salt is not particularly limited, but transition metals, noble metals, rare earth elements, and the like are preferably selected. When a transition metal is used, a transition metal catalyst having a chiral reaction field is obtained after a calcination step described later, to obtain a chiral transition metal oxide structure as the chiral metal compound structure of the present invention. Is obtained. When a noble metal is used, a chiral noble metal nanoparticle structure can be obtained as a chiral metal compound structure of the present invention after the firing step described later, and can be used as a catalyst having a chiral reaction field. It is expected to be used as a security material using plasmon absorption with circular dichroism. When a rare earth element is used, a chiral rare earth element oxide structure is obtained as the metal compound structure of the present invention after a firing step described later, and circularly polarized light emission is provided as a light emitting material with chirality. Use as a material is expected. In other words, the second metal contained in the second metal salt assumes various functions in the metal compound structure.

  Examples of the transition metal include zinc, copper, nickel, cobalt, titanium, vanadium, chromium, manganese, iron, zirconium, niobium, molybdenum, and ruthenium. Examples of the noble metal include gold, silver, palladium, and rhodium. Examples of rare earth elements include scandium, yttrium, lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium.

  Examples of the second metal salt include acetate, citrate, carbonate, oxalate, and lactate. Hydrochloride, sulfate, nitrate, etc. may also be used, but if a strong acid salt is used, the complex formation may be canceled due to the influence of the acid-base complex that forms the chiral supramolecular crystal, It can lead to undesirable results. Among these, acetate is preferable.

  The mixing ratio of the chiral supramolecular crystal and the salt of the second metal is not particularly limited, but is an amount that is 0.1 to 1.0 equivalent of the secondary amino group contained in the polyethyleneimine skeleton in the chiral supramolecular crystal. It is preferable to add a salt, and an excessive amount of salt may be added.

  When the second metal salt is allowed to act on the chiral supramolecular crystal, the chiral supramolecular crystal having undergone the sol-gel process is added to an aqueous solution in which the second metal salt is dissolved, and the mixture is stirred at room temperature for about 24 hours. Can be exemplified. Thereafter, supramolecular crystals may be filtered off, appropriately washed and dried.

  The chiral supramolecular crystal that has undergone the reactant formation step is subjected to a firing step.

[Baking process]
In the firing step, the chiral supramolecular crystal that has undergone the reactant formation step is fired to decompose the chiral supramolecular crystal that is an organic substance, and a structure composed of the coat layer and the second metal or oxide thereof is obtained. It is a process to obtain.

  In the firing step, the chiral supramolecular crystal is thermally decomposed and evaporated, and the first suprametallic compound formed on the surface of the chiral supramolecular crystal becomes an oxide, and the chiral supramolecular crystal. The second metal compound present in the interior of the metal remains. The second metal compound becomes a metal oxide when it is not a noble metal, and becomes a metal nanoparticle when it is a noble metal. Furthermore, the second metal compound becomes a metal oxide or metal nanoparticle by firing and is fixed with a three-dimensional structure, but the chirality in the chiral supramolecular crystal is transferred to this structure. Exhibits a chirality derived from In other words, the chiral supramolecular crystal serves as a template, and the chirality is transferred to the second metal compound. Therefore, the metal compound structure obtained through the firing step has chirality based on the structure such as the atomic arrangement level induced in the chiral supramolecular crystal used as a template, and is circular at the absorption wavelength of the second metal compound. It exhibits dichroism and emits circularly polarized light if the second metal is a rare earth element.

  Examples of firing conditions include heating at about 300 to 800 ° C., but are not particularly limited.

[Arylcarboxylic acid treatment step]
The metal compound structure obtained through each of the above steps can be used as a material that already exhibits circular dichroism or circularly polarized light emission, but may be treated with an arylcarboxylic acid compound as necessary. Since the arylcarboxylic acid compound has a carboxyl group capable of coordinating with the second metal and an aromatic ring having a large absorbance, this treatment can give a large absorption to the metal compound structure. The absorption given is due to the presence of the aromatic ring, but the arylcarboxylic acid exhibits the chirality induced by the second metal to which it is coordinated, so the absorption of the aromatic ring is circular. Sex will be recognized. In addition, when the second metal is a rare earth element, light absorption occurs in the aromatic ring of the arylcarboxylic acid, and then energy transfer to the rare earth element can cause more intense circularly polarized light emission. .

  When this step is performed, an arylcarboxylic acid compound may be allowed to act on the metal compound structure obtained through the firing step. More specifically, the metal compound structure to be treated may be added as a powder to a solution containing an aryl carboxylic acid and stirred at room temperature. The solvent for preparing such a solution is not particularly limited as long as it does not dissolve the metal compound structure, and examples thereof include acetone and ethyl acetate.

  The aryl carboxylic acid may be a compound having an aromatic ring and a carboxyl group, and examples thereof include benzoic acid, naphthalene carboxylic acid, anthracene carboxylic acid, and phthalic acid. These arylcarboxylic acids may be used alone or in combination.

  The concentration of the aryl carboxylic acid in the aryl carboxylic acid solution used for the treatment of the metal compound structure can be about 100 mM to 1 M, but is not particularly limited. When about 0.05 g of the metal compound structure is added to 10 mL of such a solution and stirred for about 2 hours at room temperature, the treatment is completed.

<Metal compound structure>
The metal compound structure obtained by the method for producing a metal compound structure described above is also one aspect of the present invention. Next, an embodiment of the metal compound structure of the present invention will be described.

  The metal compound structure of the present invention is a metal compound structure in which a second metal or an oxide thereof is contained inside a coat layer that is an oxide of the first metal, and the second metal or the oxidation thereof. The product is formed by firing a reaction product of a metal element constituting the second metal or its oxide and a chiral dicarboxylic acid compound inside the coat layer, and the second It exhibits circular dichroism induced by the chirality of the dicarboxylic acid compound in the absorption wavelength region of the metal or its oxide. The first metal and the second metal are the same as those already described.

  As already explained, the chiral supramolecular crystal prepared in the above crystal generation step is a crystal of a nano-sized acid-base complex, and the shape thereof is a nanofiber or nanosheet. Since the metal compound structure of the present invention is prepared using this chiral supramolecular crystal as a template, it is often formed in a nano size in which any diameter is 1 μm or less. In the metal compound structure of the present invention, chirality of the chiral supramolecular crystal serving as a template is transferred as an arrangement at the atomic or molecular level in the second metal or its oxide, and exhibits chirality. Therefore, the metal compound structure of the present invention exhibits circular dichroism induced by the chirality of the chiral supramolecular crystal at the absorption wavelength of the second metal or oxide thereof. Since the chirality of the chiral supramolecular crystal is induced by the chirality of the chiral dicarboxylic acid compound that is the raw material, the metal compound structure of the present invention has the second metal or its oxide. It can also be said that the circular dichroism induced by the chirality of the chiral dicarboxylic acid compound is exhibited at the absorption wavelength.

The coat layer is composed of a first metal oxide. This coat layer is the same as that described in the method for producing a chiral metal compound structure of the present invention, and is formed by hydrolyzing a hydrolyzable metal compound and further firing it. As described above, the compound obtained by hydrolyzing the hydrolyzable metal compound is a polymer [(-MO-) having the first metal element (M) and an oxygen atom (O). _n ] and hydroxide of the first metal element, etc. These polymer [(-MO-) _n ] and hydroxide of the first metal element are obtained by going through the firing step. Many of them are converted to oxides. In addition, even if it passes through a baking process, although a part of said polymer [(-MO-) _n ] and the hydroxide of a 1st metal element may remain | survive, in the present invention, these residues also exist. Including the oxides.

  As the first metal oxide, a silicon oxide compound derived from a hydrolyzate of alkoxysilane is preferably exemplified. The origin of the hydrolyzate of alkoxysilane is as described in the description of the method for producing the chiral metal compound structure.

  Further, when a rare earth element is selected as the metal element constituting the second metal oxide, the metal compound structure of the present invention is circularly polarized when irradiated with light having the absorption wavelength of the second metal oxide. It shows luminescence. This is also as described in the description of the method for producing the chiral metal compound structure.

  Since other matters are the same as those described in the description of the chiral metal compound structure, description thereof is omitted here.

  The chiral metal compound structure of the present invention is arranged so that transition metal oxides, noble metal compounds, rare earth element oxides, and the like exhibit chirality, and have structural chirality. Therefore, the chiral metal compound structure of the present invention is expected to be used as a catalyst having a chiral reaction field, a material exhibiting circularly polarized light emission, or the like. As described above, the material exhibiting circularly polarized light emission is expected to be applied to a three-dimensional display, as a raw material for security markers and invisible inks, and the chiral metal compound structure of the present invention is also used. Development to these uses is expected.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to the following examples.

[Synthesis of linear polyethyleneimine (LPEI)]
30 g of commercially available polyethyloxazoline (mass average molecular weight 50,000, average degree of polymerization about 500, manufactured by Aldrich) was dissolved in 5M aqueous hydrochloric acid (150 mL). The solution was heated to 90 ° C. in an oil bath and stirred at that temperature for 10 hours. Acetone (500 mL) was added to the reaction solution to completely precipitate the polymer, which was filtered off and washed three times with methanol to obtain a white polyethyleneimine powder. When the obtained powder was analyzed by ¹ H-NMR (heavy water), a 1.2 ppm peak (CH ₃ ) and a 2.3 ppm peak (CH ₂ ) derived from the ethyl group in the side chain of polyethyloxazoline Was confirmed to be completely lost. Thus, the resulting polymer showed that polyethyloxazoline was completely hydrolyzed and converted to polyethyleneimine.

  Polyethyleneimine powder was dissolved in distilled water (50 mL), and 15% aqueous ammonia (500 mL) was added dropwise to the solution while stirring. The mixture was allowed to stand overnight, and then the precipitated polymer aggregate powder was filtered, and the polymer aggregate powder was washed three times with cold water. The crystal powder after washing was dried at room temperature in a desiccator to obtain linear polyethyleneimine (LPEI). The yield was 22 g (containing crystal water). The polymer aggregate is a supramolecular complex in which polyethyleneimine molecules are crosslinked by hydrogen bonds with water molecules via secondary amino groups contained in the molecules, and have high crystallinity. . Moreover, in the polyethyleneimine obtained by hydrolysis of polyoxazoline, only the side chain chemically reacts, and the main chain does not change. Therefore, the degree of polymerization of LPEI is similar to about 500 before hydrolysis.

[Preparation of chiral supramolecular complex and sol-gel treatment for it]
Distilled water (50 mL) was added to 1.58 mg of the above-mentioned LPEI and stirred at 100 ° C. to dissolve it. Moreover, 50 mL of distilled water was added to 1.50 mg of L-(+)-tartaric acid, and this was stirred at 100 ° C. to dissolve it. Next, the L-(+)-tartaric acid aqueous solution was added to the stirring LPEI aqueous solution while being heated, and the mixture was stirred at 100 ° C. for 3 minutes. Thereafter, the solution was quenched and further cooled overnight in the refrigerator. The white solid produced in the solution was collected by centrifugation, and the resulting precipitate was washed twice with distilled water. This precipitate is a chiral supramolecular complex. Next, separately, 3 mL of tetramethoxysilane and 200 mL of distilled water were added to a plastic beaker and stirred to prepare a silica source solution. The chiral supramolecular complex precipitate was added to the silica source solution, and the mixture was stirred at room temperature for 2 hours. Thereafter, the generated precipitate was collected by centrifugation, washed twice with distilled water and twice with acetone, and then dried overnight to obtain a white solid. This white solid is formed with a coat layer made of a hydrolyzate of tetramethoxysilane (for convenience, this is treated as silica (SiO ₂ ); hereinafter the same) on the surface of the chiral supramolecular crystal by a sol-gel reaction. It is a thing. This product is called SiO ₂ @ LPEI / Tart-L. When SiO ₂ @ LPEI / Tart-L was observed with a scanning electron microscope (SEM), it was confirmed that these were spherical in which nanofiber structures were assembled.

SiO ₂ @ LPEI / Tart-D was obtained in the same procedure as described above except that D-(−)-tartaric acid was used instead of L-(+)-tartaric acid. When SiO ₂ @ LPEI / Tart-D was observed by SEM, it was confirmed that these were spherical aggregates of nanofiber structures. Since SiO ₂ @ LPEI / Tart-L and SiO ₂ @ LPEI / Tart-D are respectively prepared using chiral tartaric acid having opposite chirality, they have opposite chirality. It will be.

When the solid circular dichroism spectra (hereinafter simply referred to as CD spectra) of SiO ₂ @ LPEI / Tart-L and SiO ₂ @ LPEI / Tart-D were measured, the chirality of the supramolecular complex used as a raw material was measured. Accordingly, a negative cotton effect and a positive cotton effect were observed, respectively (FIG. 1).

Example 1 Preparation of Chiral Metal Compound Structure Containing Europium Oxide 0.57 g (1.73 mmol) of Europium Acetate was dissolved by adding 10 mL of distilled water, and SiO ₂ @ LPEI / Tart-L was added to this solution. .25 g was added and stirred at room temperature for 24 hours. Thereafter, the obtained precipitate was collected by centrifugation, washed twice with methanol and twice with acetone, and then dried at normal temperature and pressure. Subsequently, this was baked at 600 degreeC for 3 hours, and white solid was obtained. This is a compound in which LPEI and tartaric acid, which are organic substances, are decomposed by firing to form a composite composed of an oxide of europium and silica, and this is referred to as Eu ₂ O ₃ @SiO ₂ -L. Further, Eu ₂ O ₃ @SiO ₂ -D was obtained in the same procedure as above except that SiO ₂ @ LPEI / Tart-D was used as a raw material instead of SiO ₂ @ LPEI / Tart-L.

When Eu ₂ O ₃ @SiO ₂ -L and Eu ₂ O ₃ @SiO ₂ -D obtained by the above procedure were observed with an SEM, Eu ₂ O ₃ @SiO ₂ -D was found to be the same as SiO ₂ @ LPEI / Although it was confirmed that it was an aggregate of nanofiber structures similar to that of Tart-L and SiO ₂ @ LPEI / Tart-D, Eu ₂ O ₃ @SiO ₂ -L could be confirmed to be a nanofiber structure. It was found that the spherical shape of the fish was not maintained. Each nanofiber structure had a diameter of several tens of nanometers. Moreover, as a result of comparing these powder X-ray diffraction (XRD) measurement results with JCPDS data, it was confirmed that they coincided with diffraction peaks derived from europium oxide. Furthermore, when these CD spectra were measured, a positive cotton effect and a negative cotton effect were observed in Eu ₂ O ₃ @SiO ₂ -L and Eu ₂ O ₃ @SiO ₂ -D, respectively (FIG. 2). Interestingly, this was the cotton effect with the opposite sign of the raw materials SiO ₂ @ LPEI / Tart-L and SiO ₂ @ LPEI / Tart-D. This is considered to indicate that the chirality of SiO ₂ @ LPEI / Tart-L and SiO ₂ @ LPEI / Tart-D is transferred to europium oxide and maintains the chiral structure.

[Example 2] Preparation of chiral metal compound structure containing yttrium oxide 10 mL of distilled water was added to 0.57 g (1.69 mmol) of yttrium acetate and dissolved, and SiO ₂ @ LPEI / Tart-L was added to this solution. .25 g was added and stirred at room temperature for 24 hours. Thereafter, the obtained precipitate was collected by centrifugation, washed twice with methanol and twice with acetone, and then dried at normal temperature and pressure. Subsequently, this was baked at 600 degreeC for 3 hours, and white solid was obtained. This is one in which LPEI and tartaric acid, which are organic substances, are decomposed by firing to form a composite composed of yttrium oxide and silica, and this is referred to as Y ₂ O ₃ @SiO ₂ -L. _Further, except for the use of _SiO 2 @ LPEI / Tart-D as a raw material in place of the SiO 2 @ LPEI / Tart-L is at the same procedure as _above, to obtain a Y ₂ O 3 @SiO ₂ -D.

When Y ₂ O ₃ @SiO ₂ -L and Y ₂ O ₃ @SiO ₂ -D obtained by the above procedure were observed with an SEM, both of them were SiO ₂ @ LPEI / Tart-L and SiO ₂ @ LPEI / Although it was confirmed to be an aggregate of nanofiber structures similar to that of Tart-D, the shape was not a spherical shape but a rugby ball type having a twist. Each nanofiber structure had a diameter of several tens of nanometers. Moreover, as a result of comparing these powder X-ray diffraction (XRD) measurement results with JCPDS data, it was confirmed that they coincided with diffraction peaks derived from yttrium oxide. Furthermore, when these CD spectra were measured, a positive cotton effect and a negative cotton effect were observed in Y ₂ O ₃ @SiO ₂ -L and Y ₂ O ₃ @SiO ₂ -D, respectively (FIG. 3). Interestingly, this was the cotton effect with the opposite sign of the raw materials SiO ₂ @ LPEI / Tart-L and SiO ₂ @ LPEI / Tart-D. This is considered to indicate that the chirality of SiO ₂ @ LPEI / Tart-L and SiO ₂ @ LPEI / Tart-D is transferred to the yttrium oxide and maintains the chiral structure.

Example 3 Preparation of Chiral Metal Compound Structure Containing Zinc Oxide 0.38 g (1.73 mmol) of zinc acetate was dissolved in 10 mL of distilled water, and SiO ₂ @ LPEI / Tart-L was added to this solution. .25 g was added and stirred at room temperature for 24 hours. Thereafter, the obtained precipitate was collected by centrifugation, washed twice with methanol and twice with acetone, and then dried at normal temperature and pressure. Subsequently, this was baked at 600 degreeC for 3 hours, and white solid was obtained. This is one in which LPEI and tartaric acid, which are organic substances, are decomposed by firing to form a composite composed of zinc oxide and silica, and this is referred to as ZnO @ SiO ₂ -L. _Further, except for the use of _SiO 2 @ LPEI / Tart-D as a raw material in place of the SiO 2 @ LPEI / Tart-L is at the same procedure as above, to obtain a ZnO @ _SiO 2 -D.

When the ZnO @ SiO ₂ -L and ZnO @ SiO ₂ -D obtained by the above procedure were observed with an SEM, both were similar to the SiO ₂ @ LPEI / Tart-L and SiO ₂ @ LPEI / Tart-D. It was confirmed to be an assembly of nanofiber structures. Each nanofiber structure had a diameter of several tens of nanometers. Moreover, as a result of comparing these powder X-ray diffraction (XRD) measurement results with JCPDS data, it was confirmed that they coincided with diffraction peaks derived from zinc oxide. Furthermore, when these CD spectra were measured, a positive cotton effect and a negative cotton effect were observed in ZnO @ SiO ₂ -L and ZnO @ SiO ₂ -D, respectively (FIG. 4). The SiO ₂ @ LPEI / Tart-L and the SiO ₂ @ LPEI / Tart-D were cotton effects having opposite signs. This is considered to indicate that the chirality of SiO ₂ @ LPEI / Tart-L and SiO ₂ @ LPEI / Tart-D is transferred to the oxide of zinc and maintains the chiral structure.

[Example 4] Preparation of chiral metal compound structure containing rare earth oxide 50 mL of distilled water was added to 3.2 g (9.5 mmol) of yttrium acetate and 0.16 g (0.5 mmol) of europium acetate and dissolved. 0.25 g of SiO ₂ @ LPEI / Tart-L was added to the solution and stirred at room temperature for 1 hour. Thereafter, 0.90 g of urea was added to this solution and stirred at 85 ° C. for 2 hours. The obtained precipitate was collected by centrifugation, washed twice with distilled water and twice with acetone, and then dried at normal temperature and pressure. Subsequently, this was baked at 600 degreeC for 3 hours, and white solid was obtained. This is because the organic substance LPEI and tartaric acid are decomposed by firing to form a composite of yttrium oxide doped with europium and silica, and this is combined with Y ₂ O ₃ : Eu @ SiO ₂ −. Called L. Further, Y ₂ O ₃ : Eu @ SiO ₂ -D was obtained in the same procedure as described above except that SiO ₂ @ LPEI / Tart-D was used as a raw material instead of SiO ₂ @ LPEI / Tart-L. It was.

When Y ₂ O ₃ : Eu @ SiO ₂ -L and Y ₂ O ₃ : Eu @ SiO ₂ -D obtained by the above procedure were observed with an SEM, both of them were SiO ₂ @ LPEI / Tart-L and SiO. ₂ It was confirmed to be an assembly of nanofiber structures similar to @ LPEI / Tart-D. Each nanofiber structure had a diameter of several tens of nanometers. Moreover, as a result of comparing the measurement result of these powder X-ray diffraction (XRD) with JCPDS data, it was confirmed that it coincided with the diffraction peak derived from Y ₂ O ₃ : Eu. Furthermore, when these CD spectra were measured, only a few peaks were observed, but the activity derived from the absorption band of Y ₂ O ₃ : Eu appeared, and a mirror image relationship was observed between D-form and L-form. (FIG. 5). This suggests that the chirality was expressed at the metal oxide site (Y ₂ O ₃ : Eu site).

  In addition, absorption was observed at 259 nm in the UV-Vis reflection spectrum measurement of the solid powder of the metal compound structure (FIG. 6). This is considered to be derived from absorption of yttrium oxide which is a mother crystal. When this metal compound structure was irradiated with 254 nm UV light, red visible light emission was observed. From this, it is considered that the energy absorbed by the yttrium oxide serving as the antenna portion is transmitted to the doped europium, and light emission specific to europium is obtained. FIG. 7 shows the fluorescence spectrum of the solid powder when the excitation wavelength is 251 nm for this metal compound structure.

(Circularly polarized light emission characteristics)
The circularly polarized light emission characteristics of each of Y ₂ O ₃ : Eu @ SiO ₂ -L and Y ₂ O ₃ : Eu @ SiO ₂ -D obtained by the above procedure were examined. The result is shown in FIG. As shown in FIG. 8, circularly polarized light emission having opposite signs was observed between Y ₂ O ₃ : Eu @ SiO ₂ -L and Y ₂ O ₃ : Eu @ SiO ₂ -D. From this, it was shown that circularly polarized light emission can be obtained by using the metal compound structure of the present invention containing a rare earth element.

In Example 5 was obtained by dissolving the acid treated metal compound benzoic acid in the preparation of acetone 10mL of structure 0.87 g (7.1 mmol) _solution, Y ₂ O 3: Eu @ a _SiO 2 -L 0. 05 g was added and stirred at room temperature for 2 hours. The obtained precipitate was collected by centrifugation, dried at room temperature and normal pressure for 2 hours, and then dried under reduced pressure at 60 ° C. to obtain a white solid. This is referred to as BA / Y ₂ O ₃ : Eu @ SiO ₂ -L. This is equivalent to Y ₂ O ₃ : Eu @ SiO ₂ -L modified with benzoic acid. In the IR spectrum of the obtained white solid, a peak derived from the stretching vibration of C═O was observed at 1600 cm ⁻¹ , which suggests that benzoic acid is bonded to Y ₂ O ₃ : Eu. . Further, in the same procedure as above except that Y ₂ O ₃ : Eu @ SiO ₂ -D was used as a raw material instead of Y ₂ O ₃ : Eu @ SiO ₂ -L, BA / Y ₂ O ₃ : Eu @ obtain a _SiO 2 -D.

When the CD spectrum was measured for each of BA / Y ₂ O ₃ : Eu @ SiO ₂ -L and BA / Y ₂ O ₃ : Eu @ SiO ₂ -D, there was a contrasting cotton effect in the absorption region of benzoic acid. Observed (FIG. 9). The peak size of these CD spectra is similar to that of Y ₂ O ₃ : Eu @ SiO ₂ -L and Y ₂ O ₃ : Eu @ SiO ₂ -D (see FIG. 5) before introducing benzoic acid. It was significantly larger than that, and it was shown that the introduction of an achiral organic ligand resulted in an induced CD peak in the organic ligand. This is presumed that Y ₂ O ₃ : Eu was induced as a chiral site.

Example 6 Preparation of Chiral Metal Compound Structure Containing Silver Nanoparticles 0.69 g of silver acetate was added to a brown bottle and dissolved in 35 mL of 0.1N nitric acid aqueous solution. To this solution, 0.50 g of SiO ₂ @ LPEI / Tart-L was added and stirred at room temperature for 24 hours. Thereafter, the resulting precipitate was collected by centrifugation, washed twice with distilled water and twice with acetone, and then dried under reduced pressure to obtain a brown solid. The solid was then heated at 500 ° C. for 3 hours to give a yellow solid. This is referred to as Ag @ _SiO 2 -L. _Further, except for the use of _SiO 2 @ LPEI / Tart-D as a raw material in place of the SiO 2 @ LPEI / Tart-L is at the same procedure as above, to obtain a Ag @ _SiO 2 -D.

From the XRD measurement results for Ag @ SiO ₂ -L and Ag @ SiO ₂ -D obtained by the above procedure, a peak corresponding to a silver crystal was observed, and the silver calculated from the half width of the diffraction peak Since the crystal particle size of was 29.6 nm, it was shown that silver contained in this metal compound structure exists as nanoparticles. The silver ion (derived from silver acetate) used in the above preparation is ion-exchanged with tartaric acid of SiO ₂ @ PEI / Tart because of the cation, and at this time, LPEI acts as a reducing agent and Ag ⁺ ion becomes Ag ^0. Presumed to have been converted to particles. Next, when these CD spectra were measured, Ag @ SiO ₂ -L and Ag @ SiO ₂ -D exhibited a cotton effect having opposite signs in a wavelength region corresponding to plasmon absorption of silver nanoparticles. (FIG. 10). This suggests that the silver nanoparticles are three-dimensionally arranged in the metal compound structure so as to exhibit chirality.

  As described above, the metal compound structure of the present invention has a chirality based on a three-dimensional arrangement of metal oxides and metal nanoparticles, and has a chiral reaction field or a circularly polarized light-emitting material. It is understood that it is useful as such.

Claims (9)

A crystal formation step of obtaining a chiral supramolecular crystal of an acid-base type complex by reacting a polymer having a linear polyethyleneimine skeleton and a chiral dicarboxylic acid compound;
A sol gel in which a coating layer containing a first metal compound which is a hydrolyzate of the metal compound is formed on the surface of the chiral supramolecular crystal by a sol-gel method in which a hydrolyzable metal compound is allowed to act on the chiral supramolecular crystal. Process,
A reactant forming step of forming a reactant between the polyethylenimine skeleton and the dicarboxylic acid compound and the second metal by allowing a salt of the second metal to act on the chiral supramolecular crystal having undergone the sol-gel step; ,
Firing the chiral supramolecular crystal that has undergone the reactant forming step to decompose the chiral supramolecular crystal, which is an organic substance, to obtain a structure composed of the coat layer and the second metal or oxide thereof; A process for producing a chiral metal compound structure.   The method for producing a chiral metal compound structure according to claim 1, wherein the dicarboxylic acid compound is tartaric acid.   The method for producing a chiral metal compound structure according to claim 1 or 2, wherein the hydrolyzable metal compound is an alkoxysilane.   The process for producing a chiral metal compound structure according to any one of claims 1 to 3, further comprising an arylcarboxylic acid treatment step in which an arylcarboxylic acid compound is allowed to act on the structure obtained through the firing step. Method.   The method for producing a metal compound structure according to any one of claims 1 to 4, wherein the second metal is a rare earth element, and the obtained chiral metal compound structure exhibits circularly polarized light emission. . A metal compound structure in which a second metal or an oxide thereof is contained inside a coating layer that is an oxide of the first metal,
The second metal or its oxide was formed by firing a reaction product of a metal element constituting the second metal or its oxide and a chiral dicarboxylic acid compound inside the coating layer. Is,
A metal compound structure characterized by exhibiting circular dichroism induced by the chirality of the dicarboxylic acid compound in the absorption wavelength region of the second metal or oxide thereof.   The metal compound structure according to claim 6, wherein the first metal oxide is a silicon oxide compound derived from a hydrolyzate of alkoxysilane.   The metal compound structure according to claim 6 or 7, further comprising an arylcarboxylic acid compound.   The metal element constituting the second metal oxide is a rare earth element, and exhibits circularly polarized light emission when irradiated with light having an absorption wavelength of the metal oxide or the arylcarboxylic acid. Item 9. A metal compound structure according to any one of Items 6 to 8.

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