An isonicotinic acid chelated aluminum oxo-cluster compound, its macro-preparation method and application

Abstract

This invention provides an isonicotinic acid chelated aluminum oxide cluster compound, its large-scale preparation method, and its applications. The molecular formula of the aluminum oxide cluster compound is [Al6(μ3-O)2(OH)2(A)6(B)6(HB)2], where μ3-O represents a triple-linked O atom; A, whether identical or different, is independently selected from isonicotinic acid residues or isonicotinic acid residues containing substituents; B, whether identical or different, is independently selected from residues of five-membered or six-membered ring organic base compounds and their derivatives containing 1-4 nitrogen atoms. The preparation method of this invention has simple process requirements, short reaction time, is suitable for large-scale production, and produces less pollution, meeting green environmental protection requirements. The aluminum oxide cluster compound of this invention can be used in ceramics, pharmaceuticals, electronics, and other fields.

Description

Technical Field

[0001] This invention belongs to the field of crystal material preparation technology, specifically relating to a crystalline aluminum oxide cluster compound chelated with isonicotinic acid, its large-scale preparation method, and its application. Background Technology

[0002] Aluminum is the most abundant metallic element on Earth. Aluminum and its compounds are characterized by abundant reserves, low price, and low toxicity, thus attracting extensive research and being applied in various fields. The stable oxide of aluminum is alumina (Al₂O₃), a commonly used industrial catalyst (support) and adsorbent, with wide applications in ceramics, pharmaceuticals, and electronics. Crystalline aluminum oxide clusters (AlOCs) have attracted the attention of researchers from many fields, including inorganic chemistry, organic chemistry, and physical chemistry, due to their clear and tunable atomic structures, rich and diverse structural types, and the ability to simulate and study aluminum oxides at the molecular level. However, the types of aluminum oxide clusters reported so far are still limited, and they suffer from drawbacks such as long reaction times, harsh reaction conditions, poor reproducibility, and low yields, hindering large-scale production applications. Therefore, it is necessary to develop new structural types and preparation methods for aluminum oxide clusters, especially large-scale preparation methods. Summary of the Invention

[0003] To address the aforementioned technical problems, this invention provides a crystalline aluminum oxide cluster compound chelated with isonicotinic acid, its large-scale preparation method, and its applications. The preparation method of this invention is simple, efficient, environmentally friendly, and easily applicable on a large scale.

[0004] The present invention proposes the following technical solution:

[0005] This invention provides an aluminum oxide cluster compound, the molecular formula of which is:

[0006] [Al6(μ3-O)2(OH)2(A)6(B)6(HB)2]

[0007] Wherein, μ3-O represents a triple-connected O atom;

[0008] A may be the same or different, and are independently selected from residues of isonicotinic acid or residues of isonicotinic acid containing substituents;

[0009] B may be the same or different, and are independently selected from residues of organic base compounds and their derivatives containing 1-4 nitrogen atoms in a five- or six-membered ring.

[0010] According to the present invention, the A may be the same or different, and is independently selected from residues of isonicotinic acid or residues of isonicotinic acid containing substituents.

[0011] Preferably, the A residues are either the same or different and are independently selected from isonicotinic acid residues containing substituents; more preferably, they are selected from isonicotinic acid residues containing a substituent at the 2-position.

[0012] According to the present invention, the "substituent" is a conventional substituent in the art, such as selected from hydroxyl, C 1-6 Alkyl, C 1-6 Alkoxy, amino, nitro, halogen atom, preferably hydroxy, methyl, amino or halogen atom, more preferably halogen atom.

[0013] Further, the A residues are either the same or different and are independently selected from at least one of the following: residues of 2-fluoroisonicotinic acid, residues of 2-chloroisonicotinic acid, residues of 2-bromoisonicotinic acid, residues of 2-iodoisonicotinic acid, residues of 2-methylisonicotinic acid, and residues of 2-hydroxyisonicotinic acid, preferably residues of 2-chloroisonicotinic acid.

[0014] According to the present invention, the B may be the same or different and is independently selected from residues of organic base compounds and their derivatives containing 1-4 nitrogen atoms in a five-membered or six-membered ring.

[0015] Preferably, the B residues are the same or different and are independently selected from residues of five-membered ring organic base compounds and their derivatives containing 1-4 nitrogen atoms; more preferably, they are selected from residues of five-membered ring organic base compounds and their derivatives containing 1-3 nitrogen atoms; even more preferably, they are selected from residues of five-membered ring organic base compounds and their derivatives containing 1-2 nitrogen atoms.

[0016] According to the present invention, the term "derivative" refers to a compound containing a substituent as defined above, or a compound obtained by cyclic condensation of the above-mentioned organic base compound with a benzene ring. For example, benzimidazole, obtained by cyclic condensation of imidazole with a benzene ring, is an example of a compound obtained by cyclic condensation of imidazole with a benzene ring.

[0017] According to the present invention, the "organic base compounds and their derivatives containing 1-4 nitrogen atoms in a five-membered or six-membered ring" can specifically be imidazole, pyrazole, piperazine, triazole, tetrazolium, benzimidazole, benzopyrazole, benzotriazole, etc.

[0018] Further, the B residues are the same or different and are independently selected from at least one of the following: imidazole residues, pyrazole residues, piperazine residues, triazole residues, tetrazolium residues, benzimidazole residues, benzotriazole residues, 4-methylpyrazole residues, 4-fluoropyrazole residues, 4-chloropyrazole residues, 4-bromopyrazole residues, and 4-iodopyrazole residues, preferably pyrazole residues.

[0019] According to the present invention, the aluminum oxide cluster compound is a pure-phase colorless bulk crystalline substance.

[0020] According to the present invention, the aluminum oxide cluster compound has essentially the following properties: Figure 5The morphology shown. Preferably, at least one side length of the colorless blocky crystalline material is 0.1-1 mm, for example, 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, or 1.0 mm.

[0021] According to the present invention, the aluminum oxide cluster compound is an organic-inorganic hybrid compound.

[0022] According to the present invention, the cluster nucleus size of the crystalline form of the aluminum oxide cluster is

[0023] According to the present invention, the crystalline form of the aluminum oxide cluster has a symmetrical structure.

[0024] According to the present invention, the aluminum oxide cluster is a hexanuclear cluster, with an organic acid residue A, an organic base HB, and an organic base residue B coordinated on its periphery.

[0025] According to the present invention, the molecular formula of the aluminum oxide cluster is:

[0026] [Al6(μ3-O)2(OH)2(A)6(B)6(HB)2]

[0027] Where A is a residue of 2-chloroisonicotinic acid; and B is a residue of pyrazole.

[0028] It should be noted that, in this invention, the residue refers to the group remaining after removing all hydrogens from the carboxyl groups of an organic acid or the group remaining after removing all hydrogens from the nitrogen groups of an organic base.

[0029] According to an exemplary embodiment of the present invention, the molecular formula of the aluminum oxide cluster is C2. 60 H 46 N 22 O 16 Cl6Al6, denoted as aluminum oxide cluster a, has a monoclinic crystal system, space group C2 / c, and cell parameter a. b is c is α is 90°, β is 90.50°, γ is 90°, and V is...

[0030] According to the present invention, the relative molecular mass Mr of the aluminum oxide cluster a is 1703.75.

[0031] The crystalline form of the aluminum oxide cluster a has essentially the following properties: Figure 2 The X-ray powder diffraction pattern shown.

[0032] The crystal parameters of the crystalline form of the aluminum oxide cluster a are shown in Table 1.

[0033] Table 1

[0034]

[0035] According to an exemplary embodiment of the present invention, the molecular formula of the aluminum oxide cluster is C2. 60 H 46 N 22 O 16 F6Al6, denoted as aluminum oxide cluster b. Aluminum oxide cluster b has a crystal system substantially the same as that of aluminum oxide cluster a.

[0036] This invention also provides a method for preparing the above-mentioned aluminum oxide clusters, the method comprising the following steps: mixing aluminum salts, organic acids, and organic bases as reactants, reacting them under heating conditions to prepare aluminum oxide clusters.

[0037] Wherein, the residues of the organic acid form A in the molecular formula, the organic base forms HB in the molecular formula, and the organic base is deprotonated to form B in the molecular formula.

[0038] According to the present invention, the method specifically includes the following steps:

[0039] 1) The aluminum salt, organic acid, and organic base are mixed and subjected to a solvothermal reaction to obtain a mixture;

[0040] 2) Separate the mixture obtained after the reaction in step 1) to obtain the crystalline product, which is an aluminum oxide cluster compound.

[0041] According to the present invention, the aluminum salt is selected from compounds formed by removing hydrogen from the hydroxyl group of an alcohol by reacting aluminum ions with the alcohol.

[0042] Preferably, the aluminum salt is selected from at least one of aluminum ethoxide, aluminum n-propoxide, aluminum isopropoxide, aluminum n-butoxide, aluminum sec-butoxide, and aluminum tert-butoxide, and is more preferably aluminum isopropoxide.

[0043] According to the present invention, the organic acid is selected from isonicotinic acid and / or isonicotinic acid containing substituents.

[0044] According to the present invention, in the substituted isonicotinic acid, the substituent is selected from 2-hydroxy, 2-C 1-6 Alkyl, 2-C 1-6 Alkoxy group, 2-halogen atom. For example, the substituent-containing isonicotinic acid may be selected from 2-hydroxyisonicotinic acid and 2-methylisonicotinic acid.

[0045] Preferably, the organic acid is selected from at least one of 2-fluoroisonicotinic acid, 2-chloroisonicotinic acid, 2-bromoisonicotinic acid, 2-iodoisonicotinic acid, etc., and is preferably 2-chloroisonicotinic acid.

[0046] According to the present invention, the organic base is selected from five-membered or six-membered ring compounds containing 1-4 nitrogen atoms and their derivatives. Preferably, the organic base has a melting point of less than 100°C, for example, 50-95°C, so that it becomes liquid under the heating conditions of a solvothermal reaction and can be used as a solvent.

[0047] Preferably, the organic base is selected from at least one of 4-methylpyrazole, 4-chloropyrazole, 4-bromopyrazole, 4-iodopyrazole, pyrazole, imidazole, piperazine, triazole, and benzotriazole, and is preferably pyrazole.

[0048] According to the present invention, the molar ratio of the aluminum salt to the organic acid is 1:(0.01-10), for example 1:(0.1-5), specifically 1:(0.5-3).

[0049] According to the present invention, the molar ratio of the aluminum salt to the organic base is 1:(0.01-50), for example 1:(1-40), specifically 1:(10-30).

[0050] According to the present invention, the temperature of the solvothermal reaction is 50–150°C; preferably 70–120°C, for example 85–110°C, such as 100°C. If the reaction temperature is too low, the reaction time will be longer and the crystal size will be smaller.

[0051] According to the present invention, the time for the solvothermal reaction is 24 to 240 hours; preferably 36 to 180 hours, such as 72 hours or 96 hours.

[0052] For example, the solvothermal reaction can be carried out at 80°C for 120 hours or 144 hours, or at 100°C for 72 hours or 96 hours.

[0053] According to the present invention, step 1) specifically includes: mixing the aluminum salt, organic acid, and organic base, stirring, reacting at a constant temperature, and then cooling to room temperature. Room temperature in this invention refers to below 50°C, for example, 10-35°C.

[0054] Preferably, a isothermal reaction refers to a reaction that is allowed to stand at a constant temperature, such as a reaction in a heating device (e.g., an oven) with a constant temperature.

[0055] According to the present invention, in step 2), the separated crystalline material is washed and dried.

[0056] Preferably, the separated crystalline material is washed with water or alcohol and then air-dried at room temperature.

[0057] Preferably, the alcohol is selected from at least one of low-boiling-point alcohols, such as at least one of methanol, ethanol, or isopropanol.

[0058] According to the present invention, the yield of the aluminum oxide cluster compound can reach more than 30%, for example, 40%, 50%, 60%, 70%, 80%, or 90%.

[0059] The present invention also provides aluminum oxide clusters obtained by the above preparation method.

[0060] The present invention also provides applications of the above-mentioned aluminum oxide clusters, preferably in the fields of ceramics, medicine, and electronics.

[0061] According to the present invention, in the aforementioned applications, the aluminum oxide clusters can be used as nonlinear optical materials, catalysts (supports), or adsorbents.

[0062] The present invention also provides a nonlinear optical material, wherein the nonlinear optical material comprises the above-mentioned aluminum oxide cluster compound.

[0063] Beneficial effects

[0064] This invention provides a novel material, namely, isonicotinic acid-chelated crystalline aluminum oxide clusters, which have a symmetrical structure and a cluster core size of approximately The aluminum oxide clusters can be used as nonlinear optical materials, catalysts (carriers), or adsorbents, and can be applied in fields such as ceramics, medicine, and electronics.

[0065] This invention also provides a method for preparing aluminum oxide clusters, particularly a method for their large-scale preparation. The large-scale preparation method of this invention overcomes the problems of long preparation time and low yield in conventional methods for preparing crystalline aluminum oxide clusters. Furthermore, this synthesis process is simple, with a short reaction time, facilitating large-scale production. The post-processing is also simple, requiring only alcohol washing and separation followed by natural drying to obtain the crystalline product. This synthesis process uses low-toxicity and inexpensive raw materials, produces minimal pollution, and meets green environmental protection requirements. Attached Figure Description

[0066] Figure 1 This is a schematic diagram of the crystal structure of the crystalline product prepared in Example 2;

[0067] Figure 2 X-ray powder diffraction pattern of the crystalline product prepared in Example 2; wherein, "simulated value" represents the X-ray powder diffraction pattern obtained by simulating the crystal structure; "experimental value" represents the X-ray powder diffraction pattern obtained by testing on an X-ray powder diffractometer;

[0068] Figure 3 The infrared spectrum of the crystalline product prepared in Example 2;

[0069] Figure 4 Thermogravimetric analysis (TGA) diagram of the crystalline product prepared in Example 2;

[0070] Figure 5A photograph of the crystalline product prepared in Example 2;

[0071] Figure 6 The aluminum oxide cluster compound a(C) of Example 2 60 H 46 N 22 O 16 Test diagram of the third-order nonlinear optical performance of Cl6Al6. Detailed Implementation

[0072] The technical solution of the present invention will be further described in detail below with reference to specific embodiments. It should be understood that the following embodiments are merely illustrative and explanatory of the present invention, and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are covered within the scope of protection intended by the present invention.

[0073] Unless otherwise stated, the raw materials and reagents used in the following examples are commercially available products or can be prepared by known methods.

[0074] The single-crystal structure analysis of this invention was performed using Rigaku's Supernova single-crystal diffractometer from Japan.

[0075] The X-ray source used in the powder diffraction pattern was Cu-Kα rays.

[0076] Example 1

[0077] Preparation of aluminum oxide cluster compound a

[0078] Aluminum isopropoxide (1 mmol), 2-chloroisonicotinic acid (1 mmol), and pyrazole (29.38 mmol) were placed in a 20 ml glass bottle and mixed thoroughly at room temperature. The mixture was then kept at 100 °C for 3 days. After removal, the mixture was allowed to cool naturally to room temperature. The solid phase was separated, washed with ethanol, and then air-dried to obtain the colorless, blocky crystalline target product, aluminum oxide cluster a(C). 60 H 46 N 22 O 16 Cl6Al6). Yield is approximately 50% (based on the mass of aluminum isopropoxide).

[0079] Example 2

[0080] Large-scale preparation of aluminum oxide cluster a

[0081] Aluminum isopropoxide (50 mmol), 2-chloroisonicotinic acid (50 mmol), and pyrazole (1.47 mol) were placed in a 250 ml glass bottle and mixed thoroughly at room temperature. The mixture was then kept at 100 °C for 3 days. After removal, it was allowed to cool naturally to room temperature. The solid phase was separated, washed with ethanol, and then air-dried to obtain the colorless, blocky crystalline target product, aluminum oxide cluster a(C).60 H 46 N 22 O 16 Cl6Al6). Yield is approximately 50% (based on the mass of aluminum isopropoxide).

[0082] As can be seen from Examples 1 and 2, the aluminum oxide cluster compound a prepared by the present invention has a simple and easy-to-operate method for large-scale preparation. It only requires increasing the amount of feed proportionally, which facilitates large-scale production.

[0083] Example 3

[0084] Aluminum isopropoxide (0.8 mmol), 2-chloroisonicotinic acid (1.2 mmol), and pyrazole (30 mmol) were placed in a 20 ml glass bottle and mixed thoroughly at room temperature. The mixture was then kept at 100 °C for 3 days. After removal, it was allowed to cool naturally to room temperature. The solid phase was separated, washed with ethanol, and then air-dried to obtain the colorless, blocky crystalline target product, aluminum oxide cluster a(C). 60 H 46 N 22 O 16 Cl6Al6). Yield is approximately 45% (based on the mass of aluminum isopropoxide).

[0085] from Figure 1 As can be seen from the above, the aluminum oxide cluster a prepared in Example 2 has six aluminum atoms, and the outer ligands are pyrazole and 2-chloroisonicotinic acid;

[0086] from Figure 2 As can be seen from the above, the X-ray powder diffraction pattern of the aluminum oxide cluster compound a prepared in Example 2 is consistent with the theoretical simulation, indicating that this compound has high purity and is stable in air.

[0087] from Figure 3 As can be seen from the data, the vibrational characteristic peaks of the Al-O cluster nuclei of the aluminum oxide cluster compound a prepared in Example 2 are in the range of 1000-500 cm⁻¹. -1 The vibrational characteristic peaks of organic ligands are in the range of 3500-1000 cm⁻¹. -1 ;

[0088] from Figure 4 As can be seen from the above, if the aluminum oxide cluster prepared in Example 2 is used as a material, its optimal temperature range should be below 100°C. High temperature may cause the aluminum oxide cluster to be unstable.

[0089] from Figure 5 As can be seen from the above, the aluminum oxide cluster compound a prepared in Example 2 is a colorless blocky crystalline material with at least one side length of 0.1-1 mm.

[0090] Example 4

[0091] Aluminum isopropoxide (1 mmol), 2-fluoroisonicotinic acid (1 mmol), and pyrazole (30 mmol) were placed in a 20 ml glass bottle and mixed thoroughly at room temperature. The mixture was then kept at 100 °C for 3 days. After removal, the mixture was allowed to cool naturally to room temperature. The solid phase was separated, washed with ethanol, and then air-dried to obtain the colorless, blocky crystalline target product, aluminum oxide cluster compound b(C). 60 H 46 N 22 O 16 F6Al6). Yield is approximately 40% (based on the mass of aluminum isopropoxide).

[0092] The aluminum oxide cluster compound b prepared in Example 4 has the same characterization results and morphology as the aluminum oxide cluster compound a in Example 2.

[0093] Example 5

[0094] Applications of aluminum oxide clusters in nonlinear optics

[0095] 10 mg of the aluminum oxide cluster a crystal prepared in Example 2 was ultrasonically dispersed in 0.5 ml of dimethyl sulfoxide solvent to obtain a suspension (with partial dissolution of the crystals) as the test sample. Open-aperture Z-scan technology was used with an NLO-MZ instrument. An Nd:YAG laser was used as the excitation source (repetition frequency 10 Hz, period 8.5 ns, wavelength 532 nm), and all measurements were performed at room temperature. The third-order nonlinear optical properties of the dimethyl sulfoxide solvent and the test sample were measured, as shown below. Figure 6 As shown in a and b.

[0096] from Figure 6 As can be seen, the transmittance of dimethyl sulfoxide is approximately 100%, compared to... Figure 6 As shown in a and b, the Z-scan curve of the crystal prepared in Example 2 has a downward peak, exhibiting anti-saturation absorption characteristics. Its normalized transmittance is 81%, which can serve as a potential nonlinear optical material (optical limiting material).

[0097] The exemplary embodiments of the present invention have been described above. However, the scope of protection of this application is not limited to the above embodiments. Any modifications, equivalent substitutions, improvements, etc., made by those skilled in the art within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An aluminum oxide cluster compound, characterized in that, The molecular formula of the aluminum oxide cluster is: [Al6(μ3-O)2(OH)2(A)6(B)6(HB)2] Wherein, μ3-O represents a triple-connected O atom; A is selected from residues of 2-chloroisonicotinic acid, wherein the residues of 2-chloroisonicotinic acid refer to the groups remaining after all hydrogens on the carboxyl groups of 2-chloroisonicotinic acid are removed; B is selected from a residue of pyrazole, where the residue of pyrazole refers to the group remaining after all the hydrogen atoms on the nitrogen atoms of pyrazole are removed.

2. The aluminum oxide cluster compound according to claim 1, characterized in that, The aluminum oxide cluster compound is a pure-phase colorless blocky crystalline material; The aluminum oxide cluster compound is an organic-inorganic hybrid compound.

3. The aluminum oxide cluster compound according to claim 1, characterized in that, The crystalline form of the aluminum oxide cluster has a cluster core size of 17.5 mm. 0.7Å; The crystalline form of the aluminum oxide cluster has a symmetrical structure.

4. The aluminum oxide cluster compound according to claim 1, characterized in that, The aluminum oxide cluster is a hexanuclear cluster, with organic acid residue A, organic base HB and organic base residue B coordinated on its periphery.

5. The aluminum oxide cluster compound according to claim 1, characterized in that, The molecular formula of the aluminum oxide cluster is C 60 H 46 N 22 O 16 Cl6Al6, denoted as aluminum oxide cluster a, has a monoclinic crystal system and a space group of crystalline form. C2 / c Cell parameters a It is 25.50 Å. b It is 11.04 Å. c It is 26.65 Å. α For 90 o , β 90.50 o , γ For 90 o V is 7504.7 Å 3 ; The relative molecular mass Mr of the aluminum oxide cluster a is 1703.

75.

6. The aluminum oxide cluster compound according to claim 5, characterized in that, The crystal parameters of the crystalline form of the aluminum oxide cluster compound a are shown in Table 1. Table 1 。 7. The method for preparing the aluminum oxide cluster compound according to any one of claims 1-6, characterized in that, The preparation method includes: mixing aluminum salt, organic acid and organic base as reactants, reacting them under heating conditions to prepare aluminum oxide clusters; The aluminum salt is selected from aluminum isopropoxide; the organic acid is selected from 2-chloroisonicotinic acid; the organic base is selected from pyrazole; Wherein, the residues of the organic acid form A in the molecular formula, the organic base forms HB in the molecular formula, and the organic base is deprotonated to form B in the molecular formula.

8. The preparation method according to claim 7, characterized in that, The method specifically includes the following steps: 1) The aluminum salt, organic acid, and organic base are mixed and subjected to a solvothermal reaction to obtain a mixture; 2) Separate the mixture obtained after the reaction in step 1) to obtain the crystalline product, which is an aluminum oxide cluster compound; The aluminum salt is selected from aluminum isopropoxide; The organic acid is selected from 2-chloroisonicotinic acid; The organic base is selected from pyrazole.

9. The preparation method according to claim 8, characterized in that, The molar ratio of the aluminum salt to the organic acid is 1:0.01-10; The molar ratio of the aluminum salt to the organic base is 1:0.01-50; The temperature of the solvothermal reaction is 50~150℃; The solvothermal reaction time is 24-240 hours; Step 1) specifically includes: mixing the aluminum salt, organic acid and organic base, stirring, reacting at a constant temperature, and then cooling to room temperature; In step 2), the separated crystalline material is washed and dried; The yield of the aluminum oxide cluster compound is over 30%.

10. An aluminum oxide cluster compound obtained by the preparation method according to any one of claims 7-9.

11. The application of the aluminum oxide cluster compound according to any one of claims 1-6 or claim 10 in nonlinear optical materials.

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