JP5936192B2 - Chiral supramolecular crystal, solid catalyst comprising the same, and method for producing chiral supramolecular crystal - Google Patents

Description

  The present invention relates to a chiral supramolecular crystal, a solid catalyst comprising the same, and a method for producing a chiral supramolecular crystal.

  In recent years, nanostructures with specific spatial shapes and regular structures on the order of nanometers, which are obtained by self-organizing organic or inorganic compounds in an equilibrium or non-equilibrium state by intermolecular interactions, have been actively proposed. ing. 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, there are few examples of crystalline nanostructures made of polymers with crystallinity.

  In Non-Patent Document 1, after a single crystal of a polymer is formed in a mixed solution of a polymer in which ethylene glycol is bonded to the amino group of the side chain of poly (lysine) and a silica source, the single crystal is It has been reported that it grows into a nanoplate which is a composite of a polymer and silica in combination with silica. However, nanoplates derived from the polymer crystals have not been obtained in the absence of a silica source.

  On the other hand, the present inventors have already focused on the crystallization of linear polyethyleneimine, and have developed a complex hierarchical silica construction by using the fibrous crystal and the crystal in the reaction field. Then, the present inventors have found that nanosheet-like supramolecular crystals, which are acid-base complexes, are produced from linear polyethyleneimine and tartaric acid, which is a dicarboxylic acid having 4 carbon atoms (Patent Document 3). See). Polyethyleneimine has a basic secondary amino group, and tartaric acid has an acidic carboxyl group, so that a crystal composed of both of these becomes a good reaction field for reactions catalyzed by a base catalyst or an acid catalyst. Conceivable. In addition, by adding a silica source such as alkoxysilane that is hydrolyzed by an acid to the nanosheet-like crystal, it is possible to produce a nano-sized silica sheet using the nanosheet-like supramolecular crystal as a template. Conceivable.

JP 2010-208907 A JP 2009-256592 A JP 2011-126964 A

Enrico G. , Et al. , J .; Am. Chem. Soc. 2006, 128, 2276-2279

  Since tartaric acid used in the formation of the above supramolecular crystals has an optically active form, it is expected that nanostructures with chiral reaction fields can be obtained by preparing supramolecular crystals using optically active tartaric acid. The However, according to subsequent studies by the present inventors, nano-sheet-like supramolecular crystals were obtained when racemic tartaric acid was used, but fibrous supramolecular crystals were obtained when using optically active tartaric acid. However, it has been found that there is room for improvement in order to obtain crystals with a unique shape with high added value as a reaction field such as nanosheets.

  The present invention has been made in view of the above circumstances, and provides a supramolecular crystal of a chiral acid-base complex having a unique shape with a high added value as a reaction field such as a nanosheet, and a method for producing the same. This is the issue.

  As a result of intensive studies in order to solve the above problems, the present inventors surprisingly prepared glucar as a dicarboxylic acid used in combination with linear polyethyleneimine in preparing a supramolecular complex composed of an acid-base complex. When a compound having 5 or more carbon atoms such as acid or galactaric acid is used, even when an optically active dicarboxylic acid such as D-glucaric acid or D-galactaric acid is used, an acid-base type complex is formed. The inventors have found that a nanosheet-like supramolecular crystal can be obtained, and have completed the present invention. More specifically, the present invention provides the following.

  (1) The present invention provides a chiral supramolecular crystal of an acid-base complex comprising a polymer having a linear polyethyleneimine skeleton and a chiral saccharide compound which is a dicarboxylic acid and having 5 or more carbon atoms. It is.

  (2) Moreover, this invention contains at least one selected from the group which consists of an aspartic acid compound, an aspartic acid, a glucaric acid, a mannal acid, a guluronic acid, an idalic acid, a galactaric acid, and a taralonic acid (1) It is a chiral supramolecular crystal of the acid-base type complex described in the item.

  (3) Moreover, this invention is a sheet-like nanostructure, Comprising: The said nanostructure and the space formed by several said nanostructures are inside, and it is a particle | grain with a diameter of 5-50 micrometers. It is a chiral supramolecular crystal of the acid-base type complex described in the above item (1) or (2) forming a nanocomposite.

  (4) Moreover, this invention consists of the chiral supramolecular crystal of any one of said (1)-(3) term | claim, an acid or a base by the carboxyl group and basic nitrogen atom which are contained in the said supramolecular crystal It is a solid catalyst capable of catalyzing a chemical reaction promoted in the presence of.

  (5) Moreover, this invention prepares the aqueous solution of the polymer aqueous solution which prepares the aqueous solution of the polymer provided with the linear polyethyleneimine skeleton, and the aqueous solution of the chiral sugar compound which is a dicarboxylic acid and has 5 or more carbon atoms. A saccharide acid aqueous solution preparation step, a mixing step of mixing an aqueous solution of the polymer and an aqueous solution of the chiral saccharide compound to obtain a mixed aqueous solution, and leaving the mixed aqueous solution to leave the polymer and the chiral sugar in the aqueous solution; And a precipitation step of depositing an acid-base complex with an acid compound.

  (6) Moreover, the present invention is such that the two aqueous solutions mixed in the mixing step are heated, and the mixed aqueous solution prepared from the heated aqueous solutions is left to cool in the precipitation step. 5. A method for producing a chiral supramolecular crystal according to item 5).

  According to the present invention, there are provided a supramolecular crystal of a chiral acid-base complex having a unique shape with a high added value as a reaction field such as a nanosheet, and a method for producing the same.

FIG. 1 is an observation image of the composite of Example 1 by a field emission scanning electron microscope, and becomes an observation image at a low magnification as it progresses to a, b, and c. FIG. 2 is an observation image of the composite of Example 2 by a field emission scanning electron microscope, and becomes an observation image at a low magnification as it progresses to a, b, and c. FIG. 3 is an observation image by a field emission scanning electron microscope of the composite of Application Example 1 whose surface is covered with silica, and becomes an observation image at a low magnification as it progresses to a, b, and c. FIG. 4 is a solid circular dichroism spectrum of the composite of Application Example 1 whose surface is covered with silica, (a) is an ellipticity spectrum part, and (b) is a diffuse reflection spectrum part. . FIG. 5 is an observation image of the composite of Application Example 2 whose surface is covered with silica, using a field emission scanning electron microscope, and becomes an observation image at a low magnification as it progresses to a, b, and c. FIG. 6 is a solid circular dichroism spectrum of the composite of Application Example 2 whose surface is covered with silica, (a) is an ellipticity spectrum part, and (b) is a diffuse reflection spectrum part. . FIG. 7 is an observation image of the composite of Comparative Example 1 using a scanning electron microscope. FIG. 8 is an image observed by a scanning electron microscope of the composite of Comparative Example 1 whose surface is covered with silica. FIG. 9 is an observation image of the composite of Reference Example 1 with a scanning electron microscope. FIG. 10 is an image observed by a scanning electron microscope of the composite of Reference Example 1 whose surface is covered with silica.

  Hereinafter, an embodiment of a chiral supramolecular crystal of an acid-base type complex according to the present invention and a solid catalyst comprising the same, and an embodiment of a method for producing a chiral supramolecular crystal will be described. The present invention is not limited to the following embodiments or embodiments, and can be implemented with appropriate modifications within the scope of the present invention.

<Chiral supramolecular crystals of acid-base complexes>
The chiral supramolecular crystal of the acid-base complex according to the present invention comprises a polymer having a linear polyethyleneimine skeleton and a chiral sugar compound which is a dicarboxylic acid and has 5 or more carbon atoms. First, these compounds will be described.

[Polymer with linear polyethyleneimine skeleton]
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 a nitrogen atom of this amino group interacts with a carboxyl group contained in a sugar acid compound described later to form an acid-base type complex. The saccharide 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, so that the polymer is crosslinked by the saccharide acid compound. The As a result, an acid-base complex type supramolecular crystal having a structure in which a plurality of polymers and a plurality of sugar acid compounds are self-organized is formed. The characteristics of this supramolecular crystal will be described later.

(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 aggregate with the saccharide 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.

[Sugar acid compound]
The sugar acid compound used in the present invention is a dicarboxylic acid compound having 5 or more carbon atoms and is chiral. The saccharide compound may be D-form or L-form. As described above, since the sugar compound has such chirality, the resulting supramolecular crystal has a unique shape with high added value as a reaction field such as a nanosheet. The optical purity of the saccharide 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 sugar acid compound may be a dicarboxylic acid compound having 5 or more carbon atoms, whether it is linear or branched, and is a monosaccharide sugar acid or a polysaccharide sugar such as a disaccharide. Whether it is an acid or not. However, from the standpoint of obtaining good crystallinity of the supramolecular crystal, the saccharide acid compound is preferably a monosaccharide sugar acid that is linear and has carboxyl groups at both ends of the molecule. In addition, the saccharide acid compound preferably has 6 or more carbon atoms. Preferable examples of such a saccharide acid compound include altaric acid, glucaric acid, mannaric acid, guluronic acid, idalic acid, galactaric acid, and tartalic acid.

[Chiral supramolecular crystals]
The chiral supramolecular crystal of the present invention becomes a nanostructure having a specific shape such as a nano-sized sheet. The shape of the nanostructure varies depending on the type of saccharide compound used. For example, when D-glucaric acid or D-galactaric acid is used as the saccharide compound, the nanostructure is a sheet having a thickness of 1 to 100 nm. It is formed as a shape. These nanostructures are combined with each other to form a nanocomposite.

  The nanocomposite is in the form of a white powder, and the powder is a particle having a particle size of 1 to 80 μm, and particularly a particle having a particle size of 5 to 50 μm. At this time, each particle is not limited to a perfect sphere, and may be an ellipse or an irregular shape, or may be a shape in which a part of a plurality of spheres overlap. In the case of a shape such as an ellipse, the particle diameter means a portion having the longest diameter among the particles. In the case of a shape in which a plurality of spheres are overlapped, the particle diameter of each sphere is in the above range.

  The internal structure of the nanocomposite varies depending on the shape of the nanostructure to be formed, but when the nanostructure is formed as a nano-sized sheet as described above, a sheet having a thickness of about 1 to 100 nm A nanostructure in the form of a basic skeleton, which is intertwined in a complex manner to form a space inside. That is, in this case, the nanostructure is a nanocomposite having a nanostructure and a space formed by a plurality of the nanostructures inside, and having a particle diameter of 5 to 50 μm. More specifically, the nanocomposite has a multi-layered structure in which sheets having a thickness of 1 to 100 nm are overlapped with an interval (5 to 1000 nm). For this reason, the nanocomposite has a large surface area composed of chiral supramolecular crystals.

  The chiral supramolecular crystal of the present invention is an acid-base complex of a polymer having a linear polyethyleneimine skeleton having a basic secondary amino group and a saccharide compound having a carboxyl group. Therefore, the surface of the supramolecular crystal composed of both becomes a reaction field that catalyzes a chemical reaction promoted in the presence of an acid or a base. In addition, since this supramolecular crystal is chiral, the reaction field is a chiral reaction field that affects the expression of chirality in the product. In particular, as described above, when the chiral supramolecular crystal becomes a nanocomposite having a multi-layered structure with a space inside, the nanocomposite has a large surface area made of a chiral supramolecular crystal. An area reaction field will be provided. Thus, the chiral supramolecular crystal of the present invention can be used effectively as a solid catalyst.

  Examples of the reaction substrate in such a reaction field include compounds such as metal alkoxides and metal halides that are hydrolyzed with an acid or base catalyst to become metal oxides. By hydrolyzing such a reaction substrate in the above reaction field, a layer made of a metal oxide can be formed around the supramolecular crystal that is the reaction field. A metal oxide composite having The present inventors have confirmed that such a metal oxide composite has chirality derived from a chiral supramolecular crystal.

  The ratio of the polymer to the saccharide compound in the chiral supramolecular crystal of the present invention is the number of secondary amino groups (equivalent number) contained in the linear polyethyleneimine skeleton of the polymer and the number of carboxyl groups contained in the saccharide compound. (Number of equivalents). Specifically, the carboxyl group contained in the sugar acid compound is preferably 0.5 to 1.5 equivalents relative to 1 equivalent of the secondary amino group contained in the linear polyethyleneimine skeleton of the polymer, 0.9-1.1 equivalent is more preferable, and 1 equivalent is still more preferable.

<Solid catalyst>
A solid catalyst comprising the above chiral supramolecular crystal and capable of catalyzing a chemical reaction promoted in the presence of an acid or a base by a carboxyl group and a basic nitrogen atom contained in the supramolecular crystal is also the present invention. one of. This solid catalyst is composed of the above-mentioned nanocomposite and has a large surface area based on its internal structure. Therefore, high activity can be expressed as a catalyst.

  In addition, since the solid catalyst has a chiral reaction field derived from the above-described chiral supramolecular crystal, it is expected to affect the expression of chirality in the product obtained by the chemical reaction using the catalyst. . Therefore, the solid catalyst of the present invention can be used as an asymmetric synthesis catalyst.

  Examples of the chemical reaction catalyzed by the solid catalyst of the present invention include a chemical reaction promoted in the presence of an acid or a base, and examples include cyclic compounds such as esterification reaction, hydrolysis reaction, dehydration condensation reaction, and epoxy compound. Examples thereof include ring-opening polymerization reaction in (monomer). In particular, if the solid catalyst of the present invention is used in a monomer polymerization reaction, it is considered that a chiral polymer with high stereoregularity can be obtained.

<Method for producing chiral supramolecular crystal>
The method for producing the above chiral supramolecular crystal is also one aspect of the present invention. The method for producing a chiral supramolecular crystal of the present invention comprises a polymer aqueous solution preparation step for preparing an aqueous solution of a polymer having a linear polyethyleneimine skeleton, a dicarboxylic acid and a chiral saccharide compound having 5 or more carbon atoms. A step of preparing an aqueous solution of saccharide acid for preparing an aqueous solution, a step of mixing an aqueous solution of the polymer and an aqueous solution of the chiral sugar compound to obtain a mixed aqueous solution, and leaving the mixed aqueous solution to stand in the aqueous solution. And a precipitation step of precipitating an acid-base complex of the chiral sugar compound. Next, an embodiment of a method for producing a chiral supramolecular crystal will be described while explaining the above steps. In the following description, portions overlapping with the description in the above-described chiral supramolecular crystal are omitted as appropriate.

[Polymer aqueous solution preparation process]
In the production method of the present invention, first, an aqueous polymer solution preparation step is performed. In this 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.

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

[Sugar acid aqueous solution preparation process]
In parallel with the polymer aqueous solution preparation step, a sugar acid aqueous solution preparation step is performed. In this step, an aqueous solution of a carboxylic acid compound which is a dicarboxylic acid and has 5 or more carbon atoms is prepared. The sugar 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. The sugar acid compound used at this time is as already described.

  An example of a procedure for preparing an aqueous solution of a saccharide acid compound is to add the saccharide acid compound powder to distilled water and heat it to 80 ° C. or higher to dissolve the saccharide acid compound. At this time, it is preferable that the density | concentration of the saccharide acid compound in aqueous solution is the range of 0.5-15 mass%.

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

[Mixing process]
In the mixing step, the aqueous solution of the polymer and the aqueous solution of the sugar 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 mixing the aqueous solution of the polymer and the aqueous solution of the sugar acid compound, the carboxyl group contained in the sugar 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. As described above, 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 step is subjected to a precipitation step.

[Precipitation process]
In the precipitation step, the mixed aqueous solution obtained in the mixing step is allowed to stand, and an acid-base complex of a polymer and a sugar acid compound is precipitated in the aqueous solution.

  In carrying out this step, 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, and this powder is the nanocomposite already described. The nanocomposite is a composite made of a chiral supramolecular crystal that is a nanostructure. 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 resulting white precipitate is isolated by filtration. The isolated precipitate may be appropriately washed with distilled water, an organic solvent such as ethanol or acetone, and dried.

  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 (L-PEI)]
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 (L-PEI). 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 polymerization degree of L-PEI is similar to about 500 before hydrolysis.

[Example 1]
158 mg of L-PEI powder (moisture content 46 mass%) (corresponding to 2 mmol of secondary amino group) was added to distilled water (40 mL) and heated to about 100 ° C. to completely dissolve L-PEI. An aqueous polymer solution was prepared. Meanwhile, a mixed solution of 320 mg (1 mmol) of D-glucaric acid calcium (also known as D-calcium saccharic acid) tetrahydrate (manufactured by Sigma-Aldrich) in a 1 mol / L hydrochloric acid aqueous solution (2 mL) and distilled water (38 mL). In addition, it was dissolved by heating to about 100 ° C. to prepare an aqueous sugar acid solution. Thereafter, while maintaining a water temperature of about 100 ° C., a sugar acid aqueous solution was poured into the polymer aqueous solution to prepare a mixed aqueous solution. The mixed aqueous solution was allowed to cool to room temperature and then allowed to stand at 4 ° C. overnight. Thereafter, the solid produced in the mixed aqueous solution was washed and collected by centrifugation, dried, and then a complex composed of L-PEI and D-glucaric acid was obtained. The yield was 203 mg (69% yield).

  The obtained composite is placed on a glass slide, and the result of observation with a field emission scanning electron microscope (manufactured by Hitachi, Ltd., SU8010) is shown in FIG. FIG. 1 is an observation image of the composite of Example 1 by a field emission scanning electron microscope, and becomes an observation image at a low magnification as it progresses to a, b, and c. As shown in FIG. 1, a complex of L-PEI and D-glucaric acid is formed by aggregating nanosheet-like supramolecular crystals (nanostructures) having a thickness of about 100 nm, and formed by these nanostructures. It turns out that it is a spherical body provided with the space to be performed.

[Example 2]
158 mg of L-PEI powder (moisture content 46 mass%) (corresponding to 2 mmol of secondary amino group) was added to distilled water (40 mL) and heated to about 100 ° C. to completely dissolve L-PEI. An aqueous polymer solution was prepared. On the other hand, 320 mg (1 mmol) of calcium D-glucarate tetrahydrate was added to a mixed solution of 1 mol / L hydrochloric acid aqueous solution (2 mL) and distilled water (38 mL), and the mixture was heated to about 100 ° C. After dissolution, an aqueous sugar acid solution was prepared. Thereafter, while maintaining a water temperature of about 100 ° C., a sugar acid aqueous solution was poured into the polymer aqueous solution to prepare a mixed aqueous solution. The mixed aqueous solution was naturally allowed to cool to room temperature, and then a 1 mol / L hydrochloric acid aqueous solution was added dropwise at room temperature to adjust the pH of the mixed aqueous solution to 3.0. Thereafter, the mixture was allowed to stand at 4 ° C. overnight, and the solid produced in the mixed aqueous solution was washed and collected by centrifugation. After drying, a complex composed of L-PEI and D-glucaric acid was obtained. The yield was 24 mg (yield 8%).

  FIG. 2 shows the result of placing the obtained composite on a glass slide and observing it with a field emission scanning electron microscope. FIG. 2 is an observation image of the composite of Example 2 by a field emission scanning electron microscope, and becomes an observation image at a low magnification as it progresses to a, b, and c. As shown in FIG. 2, the complex of L-PEI and D-glucaric acid is formed by aggregating nanosheet-like supramolecular crystals (nanostructures) having a thickness of about 100 nm. It turns out that it is a spherical body provided with the space to be performed.

[Application Example 1]
According to the method of Example 1, 158 mg (corresponding to 2 mmol of secondary amino group) of L-PEI powder (water content 46% by mass) was added to distilled water (40 mL) and heated to about 100 ° C. -An aqueous polymer solution in which PEI was completely dissolved was prepared. On the other hand, 320 mg (1 mmol) of calcium D-glucarate tetrahydrate was added to a mixed solution of 1 mol / L hydrochloric acid aqueous solution (2 mL) and distilled water (38 mL), and the mixture was heated to about 100 ° C. After dissolution, an aqueous sugar acid solution was prepared. Thereafter, while maintaining a water temperature of about 100 ° C., a sugar acid aqueous solution was poured into the polymer aqueous solution to prepare a mixed aqueous solution. The mixed aqueous solution was allowed to cool to room temperature and then allowed to stand at 4 ° C. overnight. The next day, the polymer / sugar acid complex produced in the mixed aqueous solution was washed by centrifugation, and distilled water (10 mL) was added to prepare a white suspension. Meanwhile, tetraethyl orthosilicate (3 mL) was added to distilled water (10 mL) and stirred vigorously to prepare a silica source dispersion. The white suspension was added dropwise to the silica source dispersion and stirred at room temperature for about 2 hours. Thereafter, the solid was recovered by centrifugation and washed with distilled water and then with acetone. After drying, 598 mg of a complex of L-PEI and D-glucaric acid whose surface was covered with silica was obtained.

  The obtained composite is placed on a glass slide, and the result of observation with a field emission scanning electron microscope is shown in FIG. FIG. 3 is an observation image by a field emission scanning electron microscope of the composite of Application Example 1 whose surface is covered with silica, and becomes an observation image at a low magnification as it progresses to a, b, and c. As shown in FIG. 3, this composite is a spherical body having a space formed by nanosheet-like supramolecular crystals (nanostructures) having a thickness of about 100 nm and formed by these nanostructures. I know that there is. Moreover, when the solid circular dichroism spectrum in the state compounded with silica was measured, the ellipticity appeared in the positive direction in the ultraviolet absorption wavelength range (FIG. 4). This result suggests that the nanosheet (nanostructure) composed of L-PEI and D-glucaric acid obtained in Example 1 itself has chirality.

[Application 2]
According to the method of Example 2, 158 mg of L-PEI powder (moisture content 46 mass%) (corresponding to 2 mmol of secondary amino group) was added to distilled water (40 mL) and heated to about 100 ° C. -An aqueous polymer solution in which PEI was completely dissolved was prepared. On the other hand, 320 mg (1 mmol) of calcium D-glucarate tetrahydrate was added to a mixed solution of 1 mol / L hydrochloric acid aqueous solution (2 mL) and distilled water (38 mL), and the mixture was heated to about 100 ° C. After dissolution, an aqueous sugar acid solution was prepared. Thereafter, while maintaining a water temperature of about 100 ° C., a sugar acid aqueous solution was poured into the polymer aqueous solution to prepare a mixed aqueous solution. The mixed aqueous solution was naturally allowed to cool to room temperature, and then a 1 mol / L hydrochloric acid aqueous solution was added dropwise at room temperature to adjust the pH of the mixed aqueous solution to 3.0. Thereafter, the mixture was allowed to stand at 4 ° C. overnight, and the next day, the polymer / sugar acid complex formed in the mixed aqueous solution was washed by centrifugation. Distilled water (10 mL) was added, and the white suspension was added. Prepared. Meanwhile, tetraethyl orthosilicate (3 mL) was added to distilled water (10 mL) and stirred vigorously to prepare a silica source dispersion. The white suspension was added dropwise to the silica source dispersion and stirred at room temperature for about 2 hours. Thereafter, the solid was recovered by centrifugation and washed with distilled water and then with acetone. After drying, 137 mg of a complex of L-PEI and D-glucaric acid whose surface was covered with silica was obtained.

  FIG. 5 shows the results of placing the obtained composite on a glass slide and observing it with a field emission scanning electron microscope. FIG. 5 is an observation image of the composite of Application Example 2 whose surface is covered with silica, using a field emission scanning electron microscope, and becomes an observation image at a low magnification as it progresses to a, b, and c. As shown in FIG. 5, this composite is a twisted sphere having a space formed by nanosheet-like supramolecular crystals (nanostructures) having a thickness of about 100 nm and formed by these nanostructures. I know that there is. Moreover, when the solid circular dichroism spectrum in the state compounded with silica was measured, the ellipticity appeared in the positive direction in the ultraviolet absorption wavelength range (FIG. 6). This result suggests that the nanosheet itself composed of L-PEI and D-glucaric acid obtained in Example 2 has chirality.

[Comparative Example 1]
L-PEI (moisture content 46 mass%) powder 197.5 mg (corresponding to secondary amino group 2.5 mmol) was added to distilled water (3 mL) and heated to 95 ° C. A completely dissolved aqueous polymer solution was prepared. On the other hand, D-tartaric acid (manufactured by Tokyo Chemical Industry Co., Ltd .; carbon number 4) 187.7 mg (1.25 mmol) is dissolved in distilled water (2 mL), and the solution is heated to 95 ° C. to obtain a D-tartaric acid aqueous solution. Prepared. Thereafter, while maintaining a water temperature of about 95 ° C., an aqueous D-tartaric acid solution was poured into the aqueous polymer solution to prepare a mixed aqueous solution. A precipitate formed in the process of naturally cooling the mixed aqueous solution to room temperature was washed and collected by centrifugation, and dried in the air to obtain a complex composed of L-PEI and D-tartaric acid. Yield was 290 mg.

  FIG. 7 shows the result of placing the obtained composite on a glass slide and observing with a scanning electron microscope. FIG. 7 is an observation image of the composite of Comparative Example 1 using a scanning electron microscope. Further, the surface of the composite of Comparative Example 1 was coated with silica by treating with a silica source in the same procedure as in Application Example 1. The result of observing the composite coated with silica with a scanning electron microscope is shown in FIG. FIG. 8 is an image observed by a scanning electron microscope of the composite of Comparative Example 1 whose surface is covered with silica. As shown in FIGS. 7 and 8, the complex of L-PEI and D-tartaric acid is a composite of fibrous supramolecular crystals, which is a dicarboxylic acid and has 5 or more carbon atoms. It did not become a nanosheet-like supramolecular crystal complex as observed when a chiral sugar compound was used.

[Reference Example 1]
L-PEI (moisture content 46 mass%) powder 197.5 mg (corresponding to secondary amino group 2.5 mmol) was added to distilled water (3 mL) and heated to 95 ° C. A completely dissolved aqueous polymer solution was prepared. On the other hand, 187.7 mg (1.25 mmol) of DL-tartaric acid (manufactured by Tokyo Chemical Industry Co., Ltd .; equimolar mixture of D-tartaric acid and L-tartaric acid) was dissolved in distilled water (2 mL), and the solution was 95 ° C. The tartaric acid solution was prepared by heating until. Thereafter, an aqueous tartaric acid solution was poured into the aqueous polymer solution while maintaining a water temperature of about 95 ° C. to prepare a mixed aqueous solution. The precipitate produced in the process of naturally cooling the mixed aqueous solution to room temperature was washed and collected by centrifugation, and dried in the air to obtain a complex composed of L-PEI and DL-tartaric acid. Yield was 290 mg.

  The result of observing the obtained composite with a scanning electron microscope is shown in FIG. FIG. 9 is an observation image of the composite of Reference Example 1 with a scanning electron microscope. Further, the surface of the composite of Reference Example 1 was coated with silica by treating with a silica source in the same procedure as in Application Example 1. The result of observing the composite coated with silica with a scanning electron microscope is shown in FIG. FIG. 10 is an image observed by a scanning electron microscope of the composite of Reference Example 1 whose surface is covered with silica. As shown in FIG. 9 and FIG. 10, the complex of racemic L-PEI and DL-tartaric acid is different from the complex of chiral L-PEI and D-tartaric acid. It became a nanosheet-like supramolecular crystal complex as observed when using a chiral sugar compound with carbon atoms. However, this complex is not chiral.

Claims (6)

  A chiral supramolecular crystal of an acid-base complex comprising a polymer having a linear polyethyleneimine skeleton and a chiral sugar compound which is a dicarboxylic acid and having 5 or more carbon atoms.   2. The chiral supramolecular crystal according to claim 1, wherein the sugar acid compound includes at least one selected from the group consisting of aspartic acid, glucaric acid, mannaric acid, guluronic acid, idalic acid, galactaric acid and tartalic acid. A sheet-like nanostructure,
The chiral according to claim 1 or 2, wherein the nanostructure and a space formed by a plurality of the nanostructures are provided inside to form a nanocomposite that is a particle having a diameter of 5 to 50 µm. Supramolecular crystal.   It consists of the chiral supramolecular crystal according to any one of claims 1 to 3, and catalyzes a chemical reaction promoted in the presence of an acid or a base by a carboxyl group and a basic nitrogen atom contained in the supramolecular crystal. Solid catalyst capable. A polymer aqueous solution preparation step of preparing an aqueous solution of a polymer having a linear polyethyleneimine skeleton;
A saccharide acid aqueous solution preparation step for preparing an aqueous solution of a chiral carboxylic acid compound which is a dicarboxylic acid and has 5 or more carbon atoms;
A mixing step of mixing an aqueous solution of the polymer and an aqueous solution of the chiral sugar compound to obtain a mixed aqueous solution;
A method for producing a chiral supramolecular crystal, comprising: leaving the mixed aqueous solution and depositing an acid-base complex of the polymer and the chiral sugar compound in the aqueous solution.   The two aqueous solutions to be mixed in the mixing step are heated, and the mixed aqueous solution prepared from the heated aqueous solutions is left to cool in the precipitation step. Production method.