Metal complex and method for manufacturing the same

Abstract

To provide a novel metal complex and a method for manufacturing the metal complex.SOLUTION: The metal complex is represented by the following formula.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a metal complex and a method for producing the metal complex. [Background technology]

[0002] Metal complexes are compounds that have a structure in which metal and nonmetal atoms are bonded. Metal complexes exhibit unique properties and are used in fields such as optics, electricity, magnetism, and catalysis. For example, metal complexes are expected to be used in a variety of applications, such as optical materials and catalytic materials, and various studies are underway.

[0003] For example, Patent Document 1 describes a metal complex that has a unique structure and exhibits unique properties, and Patent Document 2 describes a phthalocyanine-based metal complex that absorbs and emits near-infrared light. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-7251 [Patent Document 2] Japanese Patent Publication No. 2023-66025 Summary of the Invention [Problem to be solved by the invention]

[0005] Metal complexes have been described as being used in a variety of applications. Metal complexes exhibit different properties depending on their structure, electronic state, etc. There is a demand for the development of new metal complexes, as well as for the advancement of existing fields and the development of new fields using new metal complexes.

[0006] The present invention has been made in view of the above problems, and an object of the present invention is to provide a novel metal complex and a method for producing the same. [Means for solving the problem]

[0007] In order to solve the above problems, the present invention provides the following means.

[0008] The metal complex according to the first aspect is represented by the following formula (1) or formula (2): In formula (1) and formula (2), M is a divalent metal element that can select a planar tetracoordinate structure, and α, β, and γ are each a hydrogen atom, an aryl group, an alkyl group having 6 or less carbon atoms, or a group in which any of these is partially substituted.

[0009] [ka]

[0010] [ka]

[0011] In the metal complex according to the above embodiment, M in formula (1) and formula (2) may be Pd or Pt.

[0012] The method for producing a metal complex according to the second aspect is the method for producing a metal complex according to the above aspect, and includes a refluxing step of refluxing a mixture obtained by mixing a diiminoisoindoline compound, a benzonitrile compound, and a divalent metal compound capable of selecting a tetraplanar coordinated structure in a solvent, and a separation step of separating the product obtained in the refluxing step. [Effects of the Invention]

[0013] The metal complex according to the above embodiment is novel and has unique properties. Furthermore, the method for producing a metal complex according to the above embodiment makes it possible to produce a novel metal complex. [Brief explanation of the drawings]

[0014] [Figure 1] 1 shows the three-dimensional structure of a first example of a metal complex according to this embodiment. [Figure 2] 1 shows the three-dimensional structure of a first example of a metal complex according to this embodiment. [Figure 3]1 shows the three-dimensional structure of a second example of a metal complex according to this embodiment. [Figure 4] 1 shows the three-dimensional structure of a second example of the metal complex according to this embodiment. [Figure 5] 1 shows the light absorption characteristics of the metal complex according to Example 1. [Figure 6] 3 shows the light absorption characteristics of the metal complex according to Example 2. [Figure 7] 1 shows the results of high-resolution mass spectrometry of the crystals of Example 1. [Figure 8] 1 shows the results of high-resolution mass spectrometry of the crystals of Example 2. [Figure 9] 1 shows the results of absorbance decay for the crystals of Example 1. DETAILED DESCRIPTION OF THE INVENTION

[0015] The present embodiment will be described in detail below. The following description is an example of the present invention, and the present invention is not limited thereto, and can be implemented with appropriate modifications within the scope of the present invention.

[0016] "Metal complexes" The metal complex according to this embodiment is represented by the following formula (1) or (2).

[0017] [ka]

[0018] [ka]

[0019] In the above formulas (1) and (2), M is a divalent metal that can have a planar tetracoordinate structure. M is, for example, any one selected from the group consisting of Pd, Pt, and Ni, and is preferably Pd or Pt.

[0020] In formulas (1) and (2), α, β, and γ each represent a hydrogen atom, an aryl group, an alkyl group having 6 or less carbon atoms, or a group in which any of these groups is partially substituted. α, β, and γ may be the same or different. Furthermore, the elements or groups at the α positions may be the same or different. Similarly, the elements or groups at the β positions may be the same or different, and the elements or groups at the γ positions may be the same or different.

[0021] The metal complex according to this embodiment is a partially modified phthalocyanine structure, and has a structure in which one of the four phthalic acid imides constituting the phthalocyanine is modified.

[0022] 1 and 2 show the three-dimensional structure of a first example of a metal complex according to this embodiment. The three-dimensional structure of the first example corresponds to the three-dimensional structure of a compound represented by formula (1). FIG. 1 shows the three-dimensional structure of the metal complex when viewed from a direction perpendicular to the plane in which the π-conjugation extends, and FIG. 2 shows the three-dimensional structure of the metal complex when viewed from one direction of the plane in which the π-conjugation extends. As shown in FIGS. 1 and 2, the metal complex represented by formula (1) has a twisted structure in which two ligand structures (structures containing benzene rings) are shifted vertically relative to the plane in which the π-conjugation extends.

[0023] 3 and 4 show the three-dimensional structure of a second example of the metal complex according to this embodiment. The three-dimensional structure of the second example corresponds to the three-dimensional structure of the compound represented by formula (2). FIG. 3 shows the three-dimensional structure of the metal complex viewed from a direction perpendicular to the plane in which the π-conjugation extends, and FIG. 4 shows the three-dimensional structure of the metal complex viewed from one direction in the plane in which the π-conjugation extends. As shown in FIGS. 3 and 4, the metal complex represented by formula (2) has a twisted structure in which two ligand structures (structures containing benzene rings) are shifted vertically relative to the plane in which the π-conjugation extends.

[0024] 1 to 4, the metal complex represented by formula (1) and the metal complex represented by formula (2) have different twisting directions of the two benzene rings. Therefore, the metal complex represented by formula (1) cannot be superimposed on the mirror image of the metal complex represented by formula (2), and has chirality.

[0025] The metal complex represented by formula (1) and the metal complex represented by formula (2) are optical isomers. The metal complex represented by formula (1) and the metal complex represented by formula (2) exhibit different optical properties. By utilizing the difference in optical properties between the metal complex represented by formula (1) and the metal complex represented by formula (2), these metal complexes can be used in polarizing filters, etc.

[0026] The light absorption characteristics of the metal complex according to this embodiment are also shown. For example, FIGS. 5 and 6 show the light absorption characteristics of Examples 1 and 2. The specific configurations of Examples 1 and 2 will be described later. As shown in FIGS. 5 and 6, the metal complex according to this embodiment can absorb near-infrared light having a wavelength of 700 nm or more. The reason why the metal complex according to this embodiment represented by formula (1) or formula (2) has absorption in the long wavelength region of 700 nm or more is not clear. The wide π-conjugation of the metal complex according to this embodiment, similar to that of phthalocyanine, is thought to be one of the reasons why the absorption peak wavelength is in the long wavelength region.

[0027] Furthermore, the metal complex according to this embodiment, represented by formula (1) or (2), has upconversion properties. Upconversion properties are a technology for converting long-wavelength light into short-wavelength light. By utilizing this property, near-infrared light can be converted into a wavelength range that can be used in solar cells and the like, thereby increasing the photoelectric conversion efficiency of solar cells. It is believed that the central metal of the metal complex contributes to the upconversion properties of the metal complex.

[0028] The metal complex according to this embodiment can be used in various applications. For example, as described above, the metal complex can be used in a dye-sensitized solar cell. The compound absorbs light in the wavelength range longer than visible light, thereby improving the power generation efficiency of the dye-sensitized solar cell.

[0029] Furthermore, for example, the compound can be used as a catalyst for producing hydrogen. The compound absorbs light in the wavelength range longer than visible light, thereby increasing the reaction efficiency of the catalyst.

[0030] Furthermore, for example, the compound can be used as a sensitizer for photodynamic therapy or photoimmunotherapy. The compound absorbs light in the wavelength range longer than visible light, which has high biological permeability, thereby increasing the efficiency of treatment in deep tissues that cannot be reached by visible light.

[0031] Furthermore, for example, the compound can be used as a contrast agent for photoacoustic imaging. The compound's ability to absorb light in the wavelength range longer than visible light increases the efficiency of the contrast agent.

[0032] Furthermore, for example, by utilizing the difference in optical properties between the metal complex represented by formula (1) and the metal complex represented by formula (2), the metal complex can be applied to a polarizing filter or the like.

[0033] Furthermore, by dispersing the metal complex according to this embodiment in a resin, a film exhibiting predetermined optical properties can be produced. The resin is not particularly limited. Examples of the resin include acrylic resin, polycarbonate resin, olefin resin, polystyrene resin, polyester resin, polyamide resin, silicone resin, thermoplastic elastomer, butyl rubber, nitrile rubber, and silicone rubber. For example, acrylic resin (polymethyl methacrylate (PMMA)) has excellent optical properties and is easily applied to optical components. This film is transparent in the visible light wavelength range and is expected to be applicable to a variety of applications. For example, this film can be used to provide a near-infrared photoelectric conversion element that selectively responds to the near-infrared light range.

[0034] "Metal Complex Manufacturing Method" The method for producing a metal complex according to this embodiment includes a refluxing step of refluxing a mixture obtained by mixing a diiminoisoindoline compound, a benzonitrile compound, and a metal compound in a solvent, and a separation step of separating the product obtained in the refluxing step.

[0035] First, a mixture of a diiminoisoindoline compound, a benzonitrile compound, and a metal compound is prepared in a solvent, and a deprotonating agent is preferably added to the mixture.

[0036] Diiminoisoindoline compounds (formula (3) below) are raw materials for forming partial skeletons similar to phthalocyanines. Diiminoisoindoline compounds include those in which a portion of pyrroline diimines is substituted with X, as shown in formula (3) below. X corresponds to the α or β portion of formulas (1) and (2), and is the same element or group as α or β. Diiminoisoindoline compounds form partial skeletons of metal complexes shown in formulas (1) and (2).

[0037] [ka]

[0038] The benzonitrile compound has two ligand structures that form a twisted structure in the metal complexes represented by formulas (1) and (2). The benzonitrile compound also includes benzonitriles having any group selected from the group consisting of a methoxy group (-OMe), a fluoro group (-F), a trifluoromethyl group (-CF3), a bromo group (-Br), and a tert-butyl group (-tBu) bonded to the benzene ring.

[0039] The metal compound is a compound of the metal ion of the metal complex represented by formula (1) or formula (2). The metal compound may be a metal salt, metal hydroxide, metal carbonyl, or the like. For example, when the metal ion is Pd, palladium(II) tetrafluoroborate (Pd(MeCN)(BF)) or the like may be used.

[0040] A deprotonating agent is a material that removes a proton from a molecule. By removing a proton from a molecule, a conjugate base is produced. Examples of deprotonating agents that can be used include DBU (diazabicycloundecene), DBN (diazabicyclononene), and TMG (tetramethyleneguanidine), with DBU being preferred.

[0041] The solvent may be 2-ethoxyethanol, 2-methoxyethanol, ethylene glycol, N,N-dimethylaminoethanol (DMAE), 1-pentanol, or the like.

[0042] The resulting mixture is then refluxed. Refluxing is preferably performed in a rare gas atmosphere, particularly preferably in an Ar atmosphere. Refluxing is preferably performed for 1 hour to 30 hours.

[0043] The mixed solution is added to the refluxed solution and suction filtered. The filtered product is separated to obtain the metal complex. The mixed solution can be, for example, a 1:1 mixture of water and methanol. Separation can be performed using methods such as chromatography and recrystallization.

[0044] According to the above-described method for producing a metal complex, the metal complexes represented by formula (1) and formula (2) can be produced using a diiminoisoindoline compound represented by formula (3) as a raw material. At the time of production, a mixture of the metal complex represented by formula (1) and the metal complex represented by formula (2) is obtained. The metal complex represented by formula (1) and the metal complex represented by formula (2) may be separated after synthesis.

[0045] As described above, by using the method for producing a metal complex according to this embodiment, a novel metal complex represented by formula (1) or formula (2) can be synthesized.

[0046] Although the preferred embodiments of the present invention have been described in detail above, the present invention is not limited to the specific embodiments, and various modifications and changes are possible within the scope of the gist of the present invention as set forth in the claims. [Example]

[0047] Example 1 In Example 1, the following chemical reactions were carried out to synthesize a metal complex.

[0048] [ka]

[0049] Under an argon atmosphere, 1,3-diiminoisoindoline (110 mg, 0.75 mmol), tetrakis(acetonitrile)palladium(II) tetrafluoroborate (182 mg, 0.41 mmol), DBU (0.1 mL, 0.67 mmol), benzonitrile (1.51 g, 14.6 mmol), and dimethylaminoethanol (2 mL) were mixed, and the mixture was refluxed for 2 hours.

[0050] Chloroform and water were then added to the refluxed solution, and the organic layer was extracted using a separatory funnel, dried over sodium sulfate, filtered, and concentrated. The resulting solid was purified by silica gel column chromatography (chloroform:hexane = 1:2), and the resulting crystals were washed with methanol. The solid was then isolated using an HPLC column to give green crystals (2 mg, 2.8 μmol) in a 7.7% yield.

[0051] The molecular structure of the obtained green crystal was measured using NMR (nuclear magnetic resonance) under the following conditions. 1 H NMR (500 MHz, CDCl3) δ=9.14-9.12(m, 2H), 9.10(d, 2H, J = 7.4 Hz), 8.97(d, 2H, J = 7.4 Hz), 8.02-8.00 (m, 2H), 7.99-7.94 (m, 4H), 7.87 (bs, 4H), 7.30-7.27 (m, 6H).

[0052] The NMR results confirmed that the molecular structure of the crystal of Example 1 was a metal complex represented by the above formula.

[0053] Furthermore, elemental analysis was performed using high-resolution mass spectrometry. Figure 7 shows the results of high-resolution mass spectrometry of the crystal of Example 1. In Figure 7, (a) is the measured value, and (b) is the theoretical value. The measured value and the theoretical value matched, confirming that the molecule was as described. HRMS-MALDI(m / z) Calcd for C 38 H 22N8Pd[M]+: 698.10068. Found: 698.09982.

[0054] The optical absorption spectrum of the produced crystal (metal complex) was also determined. Figure 5 shows the optical absorption spectrum of the crystal of Example 1. The optical absorption spectrum was measured by preparing a chloroform solution of the crystal. The absorption peak wavelength of this metal complex was 793 nm. UV-vis(CHCl3) λ max :793nm, 662nm, 341nm.

[0055] Example 2 In Example 2, the following chemical reaction was carried out to synthesize a metal complex: Example 2 differs from Example 1 in that one of the H groups of γ in the complex was changed to methoxy.

[0056] [ka]

[0057] Under an argon atmosphere, 1,3-diiminoisoindoline (240 mg, 1.65 mmol), tetrakis(acetonitrile)palladium(II) tetrafluoroborate (430 mg, 0.97 mmol), DBU (0.1 mL, 0.67 mmol), 4-methoxybenzonitrile (4.34 g, 32.6 mmol), and dimethylaminoethanol (5 mL) were mixed, and the mixture was refluxed for 2 hours.

[0058] Chloroform and water were then added to the refluxed solution, and the organic layer was extracted using a separatory funnel, dried over sodium sulfate, filtered, and concentrated. The resulting solid was purified by silica gel column chromatography (chloroform:hexane = 2:1), and the resulting crystals were washed with methanol. The solid was then isolated using an HPLC column to give green crystals (4 mg, 5.3 μmol) in a 6.5% yield.

[0059] The molecular structure of the obtained green crystal was measured using NMR (nuclear magnetic resonance) under the following conditions. 1H NMR (500 MHz, CDCl3) δ=9.02-9.00(m, 4H), 8.89(d, 2H, J = 7.4 Hz), 7.98-7.89(m, 10H), 6.82(d, 4H, J = 8.6 Hz), 3.84 (s, 6H).

[0060] NMR confirmed that the molecular structure of the crystal of Example 2 was a metal complex represented by the above formula.

[0061] Furthermore, elemental analysis was performed using high-resolution mass spectrometry. Figure 8 shows the results of high-resolution mass spectrometry of the crystal of Example 2. In Figure 8, (a) is the measured value, and (b) is the theoretical value. The measured value and the theoretical value matched, confirming that the molecule was as described. HRMS-MALDI(m / z) Calcd for C 40 H 26 N8O2Pd[M]+: 756.12080. Found: 756.12044.

[0062] The optical absorption spectrum of the produced crystal (metal complex) was also determined. Figure 6 shows the optical absorption spectrum of the crystal of Example 2. The optical absorption spectrum was measured by preparing a chloroform solution of the crystal. The absorption peak wavelength of this metal complex was 807 nm. UV-vis(CHCl3) λ max :807nm, 662nm, 394nm, 339nm.

[0063] The singlet oxygen generation performance associated with the near-infrared photosensitizer was evaluated for the metal complex synthesized in Example 1. 1,3-diphenylisobenzofuran and the metal complex were dissolved in chloroform, and the quantum yield of singlet oxygen generation was evaluated by tracking the decay of the absorbance of 1,3-diphenylisobenzofuran when the solution was irradiated with near-infrared light of 680 nm.

[0064] 9 shows the attenuation of absorbance of 1,3-diphenylisobenzofuran when zinc phthalocyanine is used as the standard substance and when the metal complex of Example 1 is used. From this result, when the quantum yield of zinc phthalocyanine is taken as Φ=0.73, the quantum yield of the metal complex can be calculated as Φ=0.04.

[0065] Since the ability to generate singlet oxygen by irradiation with near-infrared light was confirmed, it was confirmed that the metal complex can be used as a near-infrared photosensitizer. [Industrial Applicability]

[0066] The metal complex according to this embodiment can be applied to, for example, photoelectric conversion elements, imaging elements, dye-sensitized solar cells, color filters, photothermal conversion materials, near-infrared photosensitizers, catalysts, polarizing filters, and the like.

Claims

1. It is represented by the following formula (1) or formula (2): 【Chemical 1】 【Chemistry 2】 In formula (1) and formula (2), M is a divalent metal element that can select a planar tetracoordinate structure; A metal complex in which α, β, and γ each represent a hydrogen atom, an aryl group, an alkyl group having 6 or less carbon atoms, or a group in which any of these groups is partially substituted.

2. The metal complex according to claim 1, wherein M in the formula (1) and the formula (2) is Pd or Pt.

3. A method for producing the metal complex of claim 1 or claim 2, comprising: a refluxing step of refluxing a mixture obtained by mixing a diiminoisoindoline compound, a benzonitrile compound, and a divalent metal compound capable of selecting a planar tetracoordinate structure in a solvent; and a separation step of separating the product obtained in the reflux step.

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