JP5391393B2 - Method for controlling internal environment of spherical transition metal complex and spherical transition metal complex - Google Patents

Description

  The present invention relates to a method for controlling the internal environment of a spherical transition metal complex in which a hollow spherical structure is formed by a plurality of bidentate organic ligands (L) and a transition metal (M), and a spherical transition metal complex.

  In biological systems, there is a mechanism in which all biological structures such as DNA double helix and protein higher-order structure are spontaneously organized, induced by weak binding force such as hydrogen bond. In recent years, research using such a mechanism in an artificial system has attracted attention, and research using the inner surface of a natural nanoscale structure such as globular protein such as ferritin and globular virus CCMV has been conducted. These nanoscale structures have the property that even if they are decomposed by artificial stimulation, they are restored to their original structures by self-assembly. By utilizing this property, functional groups are modified on multiple subunits to form a spherical shell structure, and these subunits are self-assembled to form hollow spheres with functional groups precisely oriented on the inner surface. Research is underway to produce shell structures.

  The present inventors have paid attention to the above-described mechanism, and by using a coordinate bond having a clear direction as a driving force, it is possible to produce a precise molecular assembly spontaneously and quantitatively. We have been working on research and development of “Organic Precision Molecular System”. As a result, a large spherical shell structure with a diameter of 3 to 10 nm was manufactured by self-organization, and reported in Patent Document 1 and Non-Patent Documents 1 and 2. Such a nanoscale structure is a structure that is extremely difficult to produce by existing chemical synthesis.

  The spherical shell structure as described above is a novel molecular material that can be expected to be applied in various ways by developing the chemistry of isolated space and achieving stabilization of unstable molecules and specific substance conversion. However, in reality, it has not been realized to control the internal environment characteristics of the spherical shell structure by stimulating heat and light from the outside.

  In addition, the present inventors have conducted research for functionalizing the spherical shell structure by orienting a plurality of functional groups having an activity to polymerize by stimulating heat on the inner surface of the spherical shell structure. Proceeding, reported in Patent Document 2. However, although the internal characteristics of the spherical shell structure can be changed by polymerizing the functional group, it is difficult to return the functional group once polymerized to its original state, and it has led to reversible functionalization. Not in.

JP 2007-15947 A Specification of Japanese Patent Application No. 2006-349235 M. Fujita, et al. Nature 1995, 378, 469. Moulton, B. et al. Chem. Commun. 2001, 863. Eddaoudi, M. J. Am. Chem. Soc. 2001, 123, 4368. Tominaga, M. Angew. Chem. Int. Ed. 2004, 43, 5621. Tominaga, MJ Am. Chem. Soc. 2005, 127, 11950. Sato, S. Science 2006, 313, 1273. Murase, T. et al Angew. Chem. Int. Ed. 2007, DOI: 10.1002 / anie.200603561.

  The problem to be solved by the present invention includes the above-described problem as an example. Therefore, as an object of the present invention, for example, in a spherical transition metal complex forming a huge hollow nanoscale structure having a diameter of 3 to 10 nm, the internal environment (for example, hydrophobicity or hydrophilicity) is controlled. Is given as an example. Another example is to reversibly control the characteristics of the internal environment.

According to the method for controlling the internal environment of the spherical transition metal complex of the present invention, as described in claim 1, a hollow structure is obtained by self-organization of a plurality of bidentate organic ligands (L) and transition metals (M). A method for controlling the internal environment of a spherical transition metal complex that forms a spherical shell structure and has a plurality of functional groups linked to the bidentate organic ligands oriented inside and outside the spherical shell structure,
The functional group oriented inside the spherical shell structure is a functional group containing an azobenzene molecule,
Functional groups oriented to the outside of the spherical shell structure, formula: -NMe 3 ₊ ^· OTf ^- a functional group having a hydrophilic represented by,
In order to incorporate guest molecules into the spherical shell structure and release guest molecules from the inside,
The azobenzene molecule of the functional group is isomerized into a trans isomer by heat supplied from the outside to change the internal environment of the spherical shell structure to hydrophobic, and the azobenzene molecule of the functional group is cis isomer by ultraviolet light from the outside. The characteristics of the internal environment of the spherical shell structure are controlled so that the internal environment is restored to its original hydrophilicity by isomerization to the above.

Furthermore, the spherical transition metal complex of the present invention has a hollow spherical shell structure by self-organization of a plurality of bidentate organic ligands (L) and transition metals (M), as described in claim 3. And a spherical transition metal complex in which functional groups linked to the bidentate organic ligand are oriented inside and outside the spherical shell structure,
The functional group oriented inside the spherical shell structure is a functional group containing an azobenzene molecule,
Functional groups oriented to the outside of the spherical shell structure, formula: -NMe 3 ₊ ^· OTf ^- a functional group having a hydrophilic represented by,
The azobenzene molecule of the functional group is isomerized to a trans isomer by heat supplied from the outside to change the internal environment of the spherical shell structure to hydrophobic, and further isomerized to a cis isomer by external ultraviolet light to restore the internal environment. By returning to the hydrophilic property, the guest molecule can be taken into the inside of the spherical shell structure and the guest molecule can be released from the inside .

  A method for controlling the internal environment of the spherical transition metal complex according to a preferred embodiment of the present invention will be described in detail below. However, the present invention is not construed as being limited by the following embodiments.

  First, the spherical transition metal complex applied to this embodiment will be described. In this spherical transition metal complex, an organic ligand (L: ligand) with a functional group having isomerization activity introduced inside the curved structure and a hydrophilic functional group introduced outside is precisely designed. In addition, a spherical shell structure is formed by self-organization using a transition metal (M). At this time, by aligning a functional group having reversible isomerization activity inside the spherical shell structure, a spherical shape that can reversibly control the environment inside the shell by stimulating heat and light from the outside. A transition metal complex (C) is realized. In addition, the coordination bond used by the present inventors as a driving force for self-organization has an appropriate binding force and the directionality is clearly defined, so that a molecular assembly having a precisely controlled structure is spontaneously generated. Can be constructed both quantitatively and quantitatively. Therefore, it is possible to control various internal environments according to the purpose by precise molecular design. In addition, since the coordination number and the bond angle can be controlled in accordance with the type of metal and the oxidation number, it is possible to construct various coordination bond structures.

The spherical transition metal complex of the present embodiment includes a bidentate organic ligand (L) having at least one functional group on the inner side and the outer side of the curved structure (hereinafter simply referred to as “bidentate organic ligand (L)”). And a transition metal (M) and a molecular compound having a M _a L _2a composition (a is an integer of 6 to 60) formed in a self-organized manner. This molecular compound has a hollow three-dimensional lattice structure (referred to as a “bulb cage structure”). The size of the hollow ridge is not particularly limited, but for example, the diameter is 3 to 15 nm. The transition metals (M) and the bidentate organic ligands (L) are preferably the same, but may be different from each other.

Furthermore, since the spherical transition metal complex of this embodiment is constructed at once by self-organization using coordination bonds as driving force, M ₆ L ₁₂ , M ₁₂ L can be easily progressed. The composition is preferably ₂₄ , M ₂₄ L ₄₈ , M ₃₀ L ₆₀ , or M ₆₀ L ₁₂₀ . Among these, M ₆ L ₁₂ and M ₁₂ L ₂₄ are preferable, and M ₁₂ L ₂₄ is particularly preferable.

  The transition metal (M) that forms a spherical shell structure with the bidentate organic ligand (L) is not particularly limited, but Ti, Fe, Co, Ni, Cu, Zn, Ru, Rh, Pd, Cd, Os. , Ir and Pt are preferably a kind of metal atom or a compound thereof. Among them, a platinum group such as Ru, Rh, Pd, Os, Ir, and Pt that can easily form a planar four-coordinate complex is preferable, Ru, Pd, and Pt are more preferable, and Pd is particularly preferable. The valence of the transition metal atom is usually 0 to 4, preferably 2. The coordination number is usually 4 to 6, preferably 4.

  Examples of the transition metal (M) compound include halides, nitrates, hydrochlorides, sulfates, acetates, methanesulfonates, trifluoromethanesulfonates, and p-toluenesulfonates of the transition metals. is there. Among these, if a transition metal nitrate or trifluoromethanesulfonate is used, a desired spherical transition metal complex can be obtained efficiently.

The bidentate organic ligand (L) has a bent structure in which two coordination portions are oriented at 120 degrees by bonding two pyridyl groups to a rigid planar molecule such as furan or benzene. is there. This curved structure has at least one or more functional groups on each of the inner side and the outer side, and the transition metal (M) and the spherically selected metal are self-organized so that the inner functional group is oriented inside the hollow cage. The compound is not particularly limited as long as it can form a complex, but is preferably a compound represented by the following chemical formula.

The compound represented by the above chemical formula has an acetylene group as a bridge portion adjacent to the pyridyl group, and has a structure having a wide space between the pyridyl groups at both ends while maintaining planarity. In the formula, R 1 and R 2 each independently represent a halogen atom, an optionally substituted alkyl group, an optionally substituted alkoxyl group, a cyano group, or a nitro group. m1 and m2 each independently represents an integer of 0 to 4. When m1 and m2 are 2 or more, R1 and R2 may be the same or different from each other.

A in the above chemical formula [Chemical Formula 2] represents, for example, compounds represented by the following chemical formulas (a-1) to (a-4).

R3 in the above chemical formula [Chemical Formula 3] has an activity to isomerize by stimulating heat from the outside, and has a reversible isomerization activity to return to the original state by stimulating light from the outside. It is a functional group. Such a functional group having reversible isomerization activity is a compound containing an azobenzene molecule, for example, represented by the following chemical formula. That is, a compound having a structure in which two benzene rings are connected by a double bond (azo group) of -N = N-, and the two benzene rings are opposite to each other with the double bond (azo group) as an axis. It isomerizes reversibly between the trans form located and the cis form located on the same side.

  The above chemical formula [Chemical Formula 4] shows a structure in which two benzene rings are connected by a double bond (azo group). However, derivatives having various functional groups on the benzene ring (for example, azobenzene type) , Aminoazobenzene type, pseudostilbene type). That is, the term “azobenzene molecule” used in the present specification is defined as a generic term including derivatives having various functional groups on the benzene ring. Moreover, the functional group in the initial state (that is, the functional group introduced into the bidentate organic ligand (L) before self-organization) arranged inside the spherical shell structure by self-assembly is trans isomer and cis isomer. However, it may be introduced in a trans form that is more stable than the cis form. Here, when the functional group is a trans isomer, the environment inside the spherical shell structure is hydrophobic, and when the functional group is a cis isomer, the environment is hydrophilic.

The substituent R3 represented by the above chemical formula [Chemical Formula 3] can be linked to the bidentate organic ligand (L) via a linking group called a linker (chain). And the arrangement position of the functional group part in the inside of a spherical shell structure can be adjusted by changing the length of this linker. As such a linker, for example, a linking group represented by the chemical formula: — (O—CH ₂ ) —, — (CH ₂ ) —, —O— can be used. Twenty, preferably 1 to 10 linking groups can be joined together.

In the bidentate organic ligand (L) of this embodiment, a functional group having hydrophilicity may be further introduced outside the curved structure. The functional group having hydrophilicity is, for example, a compound represented by the chemical formula: -NMe ₃ ⁺ · OTf ⁻ . However, the present invention is not limited thereto, and a functional group containing one or more quaternary ammonium salts and a compound represented by a corresponding counter anion may be used in combination. Thus, the hydrophilic substituent is oriented on the outer surface of the spherical shell structure formed by self-assembly. As described above, when the hydrophilic substituent is oriented outside the spherical shell structure, it is possible to improve the water-durability of the spherical shell structure. That is, for example, in the bidentate organic ligand (L) represented by the following chemical formula [Chemical Formula 5], the spherical shell structure in which the hydrophilic functional group is omitted has low water-durability and is similar to DMSO. It dissolves only in fresh solutions. On the other hand, the spherical shell structure into which the functional group having hydrophilicity is introduced has an advantage that the water-durability is improved, and it can be dissolved in an aqueous solution such as a CH ₃ CN—H ₂ O solution. is there. As described above, when a hydrophilic functional group is arranged outside, the solubility in water is improved, so that it is possible to promote the uptake and release of guest molecules described later.

That is, the bidentate organic ligand (L) into which the functional group R3 having isomerization activity and the functional group R5 having hydrophilicity are introduced is preferably a compound represented by the following chemical formula. A molecular model of this bidentate organic ligand (L) and a spherical transition metal complex having an M ₁₂ L ₂₄ composition self-assembled using Pd as the transition metal (M) is shown in FIG.

  The functional group to be oriented inside the spherical shell structure is not limited to the compound containing the azobenzene molecule, and various compounds having isomerization activity can be applied, but the physical property change due to isomerization is large. And it is preferable that it is a compound with easy design to introduce | transduce into a bidentate organic ligand. That is, the type of functional group to be introduced depends on which characteristic is controlled among the characteristics of the internal environment of the spherical shell structure (for example, hydrophilicity / hydrophobicity, absorption wavelength of light such as ultraviolet light and visible light). Can be selected. As an example, when the hydrophilicity / hydrophobicity of the internal environment is mainly controlled, a functional group of azobenzenes is introduced, and when the internal light absorption wavelength is mainly controlled, diarylethenes, spiropyrans, viologens, Compounds (including derivatives) such as fulgides can be introduced.

  Here, in this embodiment, it is not necessary for all functional groups oriented inside and outside the spherical shell structure to be the same type of compound, and different types of compounds differ for each bidentate organic ligand (L). Can be introduced and oriented inside and outside the spherical shell structure. In addition, it is not necessary that all functional groups oriented inside and outside the spherical shell structure are compounds having isomerization activity and hydrophilicity, respectively, by introducing functional groups having other activities. Functionalization can also be achieved.

  Furthermore, in the present embodiment, the number of functional groups introduced into each of the bidentate organic ligands (L) forming the spherical shell structure is not limited to one. For example, the linker portion is branched into 2 or 3 2 or 3 functional groups can be introduced. At this time, the functional groups introduced into one bidentate organic ligand (L) may be of the same type or different types.

  As described above, the spherical transition metal complex of this embodiment has a structure in which substituents having reversible isomerization activity are precisely arranged on the inner surface thereof, and the environment inside the spherical shell structure is introduced. It is a characteristic according to the substituent. As a preferred example of the functional group, for example, when a compound containing a cis azobenzene molecule represented by the above chemical formula [Chemical Formula 4] is introduced, the environment inside the spherical shell structure is hydrophilic in the initial state. When heat is supplied here by heating or the like, the azobenzene molecule absorbs the heat, and the molecule moves to isomerize to the trans isomer. As a result, the environment inside the spherical shell structure changes to hydrophobicity.

  When a spherical transition metal complex in which the azobenzene molecule is isomerized into a trans isomer and the internal environment is changed to hydrophobic is irradiated with light, for example, ultraviolet light (UV), the azobenzene molecule absorbs the light, and the molecule Moves and isomerizes to the cis form. Thereby, the environment inside the spherical shell structure changes to the original hydrophilicity.

Here, Table 1 below actually produces a spherical transition metal complex having the M ₁₂ L ₂₄ composition whose molecular model is shown in FIG. 1, and performs a test that gives stimulation in the order of ultraviolet light, visible light, and heat. It is the result of having measured the content rate of the cis body, and the result of having done the same test in the state of the bidentate organic ligand (L) before making it self-assemble is also shown as a comparison.

  As is clear from the above results, the spherical transition metal complex in which a compound containing a trans azobenzene molecule is oriented inside is isomerized to a cis isomer at a rate of about 20% when irradiated with ultraviolet light. And the reverse reaction which isomerizes to a trans isomer advances by heating at 50 degreeC, and a cis isomer disappears completely.

  On the other hand, even in the ligand state, isomerization to the cis isomer proceeds by ultraviolet light, and the tendency to return to the trans isomer by heating is the same, but it should be noted that visible light was irradiated. The isomerization characteristics are different. Usually, azobenzene is known to be a substance that undergoes isomerization to the trans isomer by both visible light and heat (for example, Kumar, GS et al. Chem. Rev. 1989, 89, 1915. Natansohn). , A. et al. Chem. Rev. 2002, 102, 4139. Dugave, C. et al. Chem. Rev. 2003, 193, 2475. Yager, KG et al. J. Photochem. Photobiol., A 2006, 182 , 250.), the reaction characteristics similar to this are exhibited when it is simply introduced into the ligand.

On the other hand, when oriented inside the spherical shell structure as in this embodiment, the isomerization reaction by visible light is hindered and the isomerization to the trans isomer proceeds only by heat. Moreover, the cis body can be completely eliminated by heat. The present inventors speculate that the reason why the progress of the isomerization reaction by visible light is hindered is that the np ^* transition of the azo group has absorption in the region of visible light used, regardless of whether it is trans or cis. doing. Thus, by orienting the inside of the spherical shell structure, irreversible reaction characteristics can be imparted to azobenzene, and the possibility of various applications using the spherical transition metal complex can be increased. .

  As described above, according to the present embodiment, by introducing a functional group having an activity of isomerization by stimulating heat into a bidentate organic ligand, self-organization is performed at once by using a transition metal complex. In addition, it is possible to realize a spherical transition metal complex in which the functional group is precisely oriented on the inner surface of the spherical shell structure. This spherical transition metal complex can control the characteristics of its internal environment (for example, hydrophilicity, hydrophobicity, light absorption wavelength) by isomerizing the functional group by stimulating heat from the outside. It is.

  That is, the spherical transition metal complex of this embodiment is, for example, Wang, G. et al. Macromolecules 2004, 37, 8911. Tong, X. et al. J. Phys. Chem. B 2005, 109, 20281. Lee, H. et al. Macromolecules 2006, 39, 3914. Liu, X. Angew. Chem Int. Ed. 2006, 45, 3846, micelles with copolymers containing azobenzene, Archut, A. et al J. Am. Chem. Soc. 1998, 120, 12187. Archut, A. Chem. Soc. Rev. 1998, 27, 233. Jiang, D.-L. et al. Nature 1997, 388, 454. Wang, Compared to azobenzene-containing dendrimers as disclosed in S. et al. J. Org. Chem. 2004, 69, 9073, it is extremely effective in that its properties can be controlled at the nanoscale. It is a novel invention.

  Furthermore, according to the spherical transition metal complex of this embodiment, the internal environment of the spherical structure can be restored by introducing a functional group having reversible isomerization activity that is restored to the original state by light from the outside. it can. This makes it possible to realize a novel spherical transition metal complex having a so-called switching function. In particular, if a functional group composed of a compound containing azobenzene is introduced, the environment inside the spherical shell structure can be completely changed to hydrophobicity by stimulating heat, and light is stimulated to return to the original hydrophilicity. It becomes possible. In addition, the degree of hydrophilicity or hydrophobicity can be finely controlled by adjusting the heat supply amount and the light irradiation amount.

  As described above, the spherical transition metal of the present embodiment can control the hydrophilicity and hydrophobicity of the interior by supplying heat or light. It is possible to control the function to be captured in That is, for example, when the guest molecule has hydrophobicity, the incorporation of the guest molecule is promoted by making the internal environment of the spherical shell structure hydrophobic, and then the internal environment is changed to hydrophilic. This facilitates the release of guest molecules. Examples of guest molecules that can be used include drugs, fluorescent substances, dyes, fullerenes, carbon nanotubes, and polymers.

(Production method)
Hereinafter, an example of a method for producing the above-described spherical transition metal complex will be described. First, the bidentate organic ligand (L) can be produced by applying a known synthesis method. For example, among the compounds represented by the above chemical formula [Chemical Formula 2], the compound (I-2) in which R1 and R2 are of the same type can be obtained by methods known in the literature (K. Sonogashira, Y. Tohda, N Hagihara, Tetrahedron Lett., 1975, 4467; JF Nguefack, V. Bolitt, D. Sinou, Tetrahedron Lett., 1996, 31, 5527).

In the formula, A, R1 and m1 represent the same meaning as described above. (A-1) represents a compound represented by the formula: X-A-X. X represents a halogen atom such as a chlorine atom, a bromine atom, or an iodine atom.

That is, the compound represented by the formula (I-2) includes a base, a palladium catalyst such as Pd (PhCN) ₂ Cl ₂ / P (t-Bu) ₃ , Pd (PPh ₃ ) _{4 in} an appropriate solvent, and In the presence of a copper salt such as cuprous iodide, 4-ethynylpyridines (or a salt thereof) represented by the formula (II) are reacted with the compound (A-1) represented by the formula (III). Can be obtained.

  The above reaction is an example in which two 4-ethynylpyridines (or salts thereof) are reacted at once to produce a compound having two identical pyridinylethynyl groups. Compounds having different substituted pyridylethynyl groups can be obtained by reacting the corresponding 4-ethynylpyridines (or salts thereof) stepwise under similar reaction conditions.

  Examples of the base used here include amines such as dimethylamine, diethylamine, diisopropylamine, triethylamine, and diisopropylethylamine.

  As a solvent to be used, ethers such as 1,4-dioxane, diisopropyl ether, tetrahydrofuran (THF), 1,3-dimethoxyethane; amides such as dimethylformamide; sulfoxides such as dimethyl sulfoxide; nitriles such as acetonitrile; Etc. The reaction temperature is usually in the temperature range from 0 ° C. to the boiling point of the solvent, preferably 10 ° C. to 70 ° C., and the reaction time is usually several minutes to several tens of hours depending on the reaction scale and the like.

  4-Ethynylpyridine (or a salt thereof) can be produced by a known method, but a commercially available product can also be used as it is.

  Moreover, the compound represented by Formula (III) can be manufactured by a well-known method. For example, the compound (A-1) used for the production of the compound represented by the formula (I-2) can be synthesized, for example, by the following method.

(Wherein R3, R5 and X represent the same meaning as described above, D corresponds to the above-mentioned linking group, L represents a leaving group), that is, the compound represented by formula (IV) and formula (V The compound represented by the formula (III-1) can be obtained by reacting the compound represented by) in the presence of a base. Furthermore, the compound represented by the formula (III-2) can be obtained by reacting the compound represented by the formula (III-1) with the compound represented by the formula (VI).

  Examples of the base used include inorganic bases such as sodium hydrogen carbonate, sodium carbonate, potassium carbonate, sodium hydroxide, sodium hydride; triethylamine, pyridine, 1,8-diazabicyclo [5.4.0] -7-undecene (DBU). ); Metal alkoxides such as potassium t-butoxide and sodium methoxide; and the like.

  This reaction is preferably carried out in a solvent. The solvent to be used is not particularly limited as long as it is an inert solvent for the reaction. For example, ethers such as diethyl ether, THF, 1,4-dioxane; aromatic hydrocarbons such as benzene, toluene, xylene; halogenated hydrocarbons such as dichloromethane, chloroform, 1,2-dichloroethane; acetonitrile, etc. Nitriles; Amides such as dimethylformamide (DMF); Sulfoxides such as dimethyl sulfoxide (DMSO); Aromatic amines such as pyridine;

  This reaction proceeds smoothly in the temperature range from −15 ° C. to the boiling point of the solvent used. The reaction time is several minutes to 50 hours depending on the reaction scale and the like.

When the bidentate organic ligand (L) is produced by the above-described method, the bidentate organic ligand (L) is added in an amount of 1 to 5 mol, preferably 2 to 3 with respect to 1 mol of the transition metal (M). The reaction is carried out at a molar ratio. The use ratio of the transition metal (M) and the bidentate organic ligand (L) can be appropriately set according to the composition of the target spherical transition metal complex. For example, when it is desired to obtain the transition metal complex having the composition of the formula: M ₁₂ L ₂₄ described above, 2 to 3 mol of the bidentate organic ligand (L) is added to 1 mol of the transition metal (M). What is necessary is just to make it react in a ratio.

  The reaction between the transition metal (M) and the bidentate organic ligand (L) can be carried out in a suitable solvent. Solvents used include nitriles such as acetonitrile; sulfoxides such as dimethyl sulfoxide (DMSO); amides such as N, N-dimethylformamide; diethyl ether, tetrahydrofuran, 1,2-dimethoxyethane, 1,4-dioxane, etc. Ethers; halogenated hydrocarbons such as dichloromethane and chloroform; aliphatic hydrocarbons such as pentane and hexane; aromatic hydrocarbons such as benzene and toluene; alcohols such as methanol, ethanol and isopropyl alcohol; acetone, Ketones such as methyl ethyl ketone; cellosolves such as ethyl cellosolve; water and the like. These solvents can be used alone or in combination of two or more.

  The reaction between the transition metal (M) and the bidentate organic ligand (L) proceeds smoothly in a temperature range from 0 ° C. to the boiling point of the solvent used. The reaction time is several minutes to several days. After completion of the reaction, the desired spherical transition metal complex can be isolated by performing usual post-treatments such as filtration, column purification with an ion exchange resin, distillation, recrystallization and the like.

The counter ion of the obtained spherical transition metal complex is usually an anion of the transition metal (M) to be used. However, the counter ion is used for the purpose of improving crystallinity or improving the stability of the polymerizable spherical transition metal complex. Ions may be exchanged. Examples of such counter ions include PF ₆ ⁻ , C 1 O ₄ ⁻ , SbF ₄ ⁻ , AsF ₆ ⁻ , BF ₄ ⁻ and SiF ₆ ²⁻ .

The structure of the obtained spherical transition metal complex is known as ¹ H-NMR, ¹³ C-NMR, IR spectrum, mass spectrum, visible light absorption spectrum, UV absorption spectrum, reflection spectrum, X-ray crystal structure analysis, elemental analysis, etc. This can be confirmed by means of analysis.

  As described above, the method for controlling the internal environment of the spherical transition metal complex of the present invention forms a hollow spherical shell structure by self-organization of a plurality of bidentate organic ligands (L) and transition metals (M). At the same time, the functional group having isomerization activity linked to the bidentate organic ligand is isomerized by heat supplied from the outside to the spherical transition metal complex in which a plurality of functional groups are oriented inside the spherical shell structure. To control the internal environment characteristics of the spherical shell structure. Accordingly, the functional group is isomerized by stimulating heat from the outside, and the characteristics (for example, hydrophilicity, hydrophobicity, light absorption wavelength) inside the spherical shell structure can be controlled. Thus, the spherical transition metal complex of the present invention is a very effective invention in that the characteristics of its internal environment can be controlled at the nanoscale.

Then, the Example which manufactured the bidentate organic ligand (L) represented by the said Chemical formula [Chemical Formula 5], and also manufactured the spherical transition metal complex by self-organization is demonstrated. The production route of the bidentate organic ligand (L) is as follows. However, the present invention is not limited by the following examples.

Synthesis of compound (4).
The compound (3) 3,5-dibromo-4-hydroxybenzyl alcohol (3.04 g, 10.8 mmol) and 4-bromomethylazobenzene (2.76 g, 10.0 mmol) were dissolved in 80 mL of DMF, and carbonic acid was added thereto. 3.07 g (22.2 mmol) of potassium was added and the reaction mixture was stirred at 100 ° C. for 12 hours. The solvent was then evaporated and the residue redissolved in chloroform. The precipitate was then removed by filtration, and the filtrate was concentrated under reduced pressure. The resulting concentrate was purified by silica gel column chromatography (ethyl acetate / hexane = 1: 3) to give orange powdery compound (4). 2.16 g (4.53 mmol) was obtained (45% yield).

Synthesis of compound (5) 1.21 g (2.53 mmol) of the obtained compound (4), 1.08 g (7.70 mmol) of 4-ethynylpyridine hydrochloride, Pd (PhCN) ₂ Cl ₂ ( 61.6 mg, 0.161 mmol) and cuprous iodide (CuI) 21.3 mg (0.112 mmol) were added to a degassed dioxane solution (18 mL). .90 mL (0.30 mmol; 10% hexane solution) and diisopropylamine 4.5 mL (32 mmol) were further added. The mixture was stirred at 50 ° C. for 21 hours under an argon atmosphere. The reaction mixture was diluted with chloroform (20 mL), filtered, the filtrate was concentrated under reduced pressure, and the concentrate was redissolved in chloroform. The chloroform layer was washed successively with water containing ethylenediamine and brine, dried over anhydrous sodium sulfate, filtered, and the filtrate was concentrated under reduced pressure. The resulting concentrate was subjected to silica gel column chromatography (chloroform to chloroform / methanol = 30: 1 gradient elution) to give 1.26 g (2.42 mmol) of orange powdery compound (5) (96% yield).

Compound (7)
To a dry THF solution (45 mL) in which the compound (5) was dissolved, 561 mg (2.14 mmol) of triphenylphosphine and 931 mg (2.81 mmol) of carbon tetrabromide were added at room temperature under an argon atmosphere. After stirring for 3 hours, the amount of compound (6) in the solution was quantified using MALDI-TOF MS. The solution was treated with 22 ml (94.6 mmol; 4.3 M aqueous solution) of trimethylamine and stirred at room temperature for 21 hours. The solvent was then evaporated and the residue was dissolved in chloroform. The chloroform layer was washed with an aqueous sodium bromide solution, dried over anhydrous sodium sulfate, filtered, and the filtrate was concentrated under reduced pressure. The resulting concentrate was subjected to silica gel column chromatography (CH ₃ CN ₃ / H ₂ O (10 wt. % NaBr) = 50: 1 to CH ₃ CN ₃ / H ₂ O (10 wt% NaBr) = 10: 1 gradient elution) to give 580 mg (0.902 mmol) of orange powdery compound (7) ) Obtained (yield 94%)

-Synthesis of bidentate organic ligand (1) 94.6 mg (0.147 mmol) of the obtained compound (7) and 37.9 mg (0.147 mmol) of silver trifluoromethanesulfonate were dissolved in acetonitrile (8 mL). I let you. The reaction mixture was stirred at room temperature under an argon atmosphere for 12 hours, filtered, and concentrated under reduced pressure to obtain 96.9 mg (0.136 mmol) of an orange powdery compound (yield 93%).

Synthesis of spherical transition metal complex (2) 12.6 mg (17.7 mmol) of bidentate organic ligand (1) is contained at 4 ° C. for 4 hours with Pd (CF ₃ SO ₃ ) ₂ being a transition metal. The spherical transition metal complex (2) was formed by self-assembly by treatment with 1.8 mL (8.9 mmol; 4.9 mM CD ₃ CN solution) of the solution. The spherical transition metal complex (2) was quantified by ¹ H NMR. By adding diethyl ether to this solution, an orange solid precipitated. As a result, 14.4 mg (0.658 mmol) of the spherical transition metal complex (2) was obtained (yield 89%).

(Test Example 1)
The ¹ H-NMR spectrum (a) of the spherical transition metal complex (2) obtained by the above method and the ¹ H-NMR spectrum (b) after irradiation with ultraviolet light are shown in FIG. First, according to the spectrum (a), it can be seen that the azobenzene molecule oriented inside the spherical shell structure is a trans isomer. And according to the spectrum (b) after irradiating with ultraviolet light, it can be confirmed that isomerization from the trans isomer to the cis isomer proceeds at a rate of 23%.

Shows a molecular model of spherical transition metal complex M ₁₂ L ₂₄ composition according to embodiments of the present invention. It is a characteristic view which shows the result of the test done in order to confirm the effect of this invention, and shows the < ¹ > H-NMR spectrum before and after irradiating a spherical transition metal complex with ultraviolet light.

Claims (4)

A hollow spherical shell structure is formed by self-assembly of a plurality of bidentate organic ligands (L) and transition metals (M), and the functional group linked to the bidentate organic ligand is the spherical shell structure. A method for controlling the internal environment of a spherical transition metal complex that is oriented multiple times inside and outside the body,
The bidentate organic ligand (L) has the following chemical formula (I)

Wherein R ¹ and R ² are any of a halogen atom, an optionally substituted alkyl group, an optionally substituted alkoxyl group, a cyano group, and a nitro group. M1 and m2 are each independently Any of integers from 0 to 4. When m1 and m2 are 2 or more, R1 and R2 may be the same or different from each other.
A in the chemical formula (I) is (a-1) or (a-2) in the following chemical formula (II):

Indicated by
The functional group oriented inside the spherical shell structure is R ³ in the chemical formula (II), and includes a azobenzene molecule represented by the following chemical formula (III),


The functional group oriented outside the spherical shell structure is R ⁴ in the chemical formula (II), and is a functional group having hydrophilicity represented by the chemical formula: —CH ₂ NMe ₃ ⁺ · OTf ^—
In order to incorporate guest molecules into the spherical shell structure and release guest molecules from the inside,
The azobenzene molecule of the functional group is isomerized into a trans isomer by heat supplied from the outside to change the internal environment of the spherical shell structure to hydrophobic, and the azobenzene molecule of the functional group is cis isomer by ultraviolet light from the outside. A method for controlling the internal environment of a spherical transition metal complex, characterized in that the internal environment characteristics of the spherical shell structure are controlled so that the internal environment is restored to its original hydrophilicity by isomerization.   The method for controlling the internal environment of a spherical transition metal complex according to claim 1, wherein the bidentate organic ligand (L) is a bidentate organic ligand (L) having a curved structure. . A hollow spherical shell structure is formed by self-assembly of a plurality of bidentate organic ligands (L) and transition metals (M), and the functional group linked to the bidentate organic ligand is the spherical shell structure. A spherical transition metal complex oriented inside and outside the body,
The bidentate organic ligand (L) has the following chemical formula (I)

Wherein R ¹ and R ² are any of a halogen atom, an optionally substituted alkyl group, an optionally substituted alkoxyl group, a cyano group, and a nitro group. M1 and m2 are each independently Any of integers from 0 to 4. When m1 and m2 are 2 or more, R1 and R2 may be the same or different from each other.
A in the chemical formula (I) is (a-1) or (a-2) in the following chemical formula (II):

The functional group oriented inside the spherical shell structure is R ³ in the chemical formula (II), and includes a azobenzene molecule represented by the following chemical formula (III),


The functional group oriented outside the spherical shell structure is R ⁴ in the chemical formula (II), and is a functional group having hydrophilicity represented by the chemical formula: —CH ₂ NMe ₃ ⁺ · OTf ^—
The azobenzene molecule of the functional group is isomerized to a trans isomer by heat supplied from the outside to change the internal environment of the spherical shell structure to hydrophobic, and further isomerized to a cis isomer by external ultraviolet light to restore the internal environment. A spherical transition metal complex characterized in that the guest molecule can be taken into the inside of the spherical shell structure and the guest molecule can be released from the inside by returning to the hydrophilic property of. The spherical transition metal complex according to claim 3, wherein the bidentate organic ligand (L) is a bidentate organic ligand (L) having a curved structure.