A three-dimensional organic eutectic material, its preparation method and application

Abstract

A three-dimensional organic eutectic material, its preparation method, and its applications are disclosed, belonging to the field of chemical technology. The organic eutectic material is formed by the self-assembly of donor and acceptor molecules through non-covalent bonds, resulting in three-dimensional organic eutectics with well-defined crystal faces and diverse morphologies, achieving structural diversity. The preparation process is flexible and controllable, allowing for both direct co-crystallization of donor and acceptor molecules and controlled crystallization through in-situ synthesis of donor molecules. It solves the solubility problem of donor and acceptor molecules and possesses the ability to control morphological diversity. Preparation can be completed in an aqueous system at 0–100℃ with a reaction time of only 1–10 min, avoiding the limitations of traditional methods such as slow crystallization due to solvent evaporation and lengthy preparation processes; it also overcomes dependence on organic solvents; and its environmental friendliness and suitability for large-scale production promote the practical application of three-dimensional materials. This organic eutectic material exhibits excellent performance in the photocatalytic preparation of hydrogen peroxide.

Description

Technical Field

[0001] This invention belongs to the field of chemical technology, specifically relating to a crystalline polyhedral organic eutectic material, its preparation method, and its applications. Background Technology

[0002] Organic cocrystals are crystalline materials with fixed stoichiometry and ordered stacking structures formed by the mutual recognition and co-assembly of two or more organic molecules through intermolecular non-covalent interactions (such as p-p stacking, hydrogen bonding, and van der Waals forces). Their unique chemical structure, highly ordered molecular arrangement, and excellent properties have attracted widespread research interest. Organic cocrystals possess high photoelectric conductivity, room-temperature ferroelectricity, and two-photon absorption properties, showing broad application potential in multiple fields. For example, in photothermal therapy and imaging, organic cocrystals can achieve efficient photothermal conversion and imaging; in the field of two-photon absorption, organic cocrystals exhibit excellent two-photon absorption characteristics, providing new materials for three-dimensional fluorescence microscopy and optical information storage; organic cocrystals can also be used to prepare high-performance field-effect transistors and optoelectronic devices; in the pharmaceutical field, organic cocrystal engineering can greatly improve the solubility, bioavailability, and stability of drugs while maintaining their original efficacy. Organic cocrystals possess unique tunability in molecular structure; by changing the molecular stacking pattern of the original units, molecules can be rearranged in an ordered manner, revealing the relationship between structure and properties at the molecular level, and providing a broad platform for the design and synthesis of new materials.

[0003] Organic eutectic engineering manipulates the interactions of organic molecules by selecting appropriate constituent units, resulting in tunable structures, morphologies, and sizes. Through collaborative strategies among different constituent units, it achieves rare and multifunctional properties, demonstrating significant scientific importance and practical value in the development of novel functional materials. However, traditional organic eutectics are mostly assembled from planar small organic molecules as donors and acceptors, typically using only two methods: fractional or staggered columnar stacking, which limits the diversity of eutectic assembly structures.

[0004] Compared to traditional covalent organic synthesis methods, organic cocrystal preparation strategies offer a simple, environmentally friendly, and low-cost method for constructing non-covalent materials, avoiding complex synthetic procedures and lengthy steps. Significant efforts have been made to prepare organic cocrystal materials, and many effective methods have been developed, including mechanical grinding, solvent evaporation, recrystallization, and sublimation cocrystallization. However, not all methods are readily and effectively suitable for preparing organic cocrystal materials. For example, solvent evaporation is slow; recrystallization requires uniform solvent solubility in the sample, and for DA-type reaction systems (donor (D) and acceptor (A), the solubility of the donor and acceptor molecules often differs significantly; sublimation cocrystallization is only suitable for substances with high boiling points, and suffers from high cost, high energy consumption, and low yield. Furthermore, it is difficult to control the non-covalent interactions between molecules during crystal growth, often making it difficult to precisely control the size and morphology of molecular crystals. These problems limit the large-scale commercial application of organic cocrystal materials.

[0005] Therefore, developing structurally diverse organic eutectic materials and their simple, low-cost, large-scale synthesis strategies is undoubtedly an ideal direction. However, due to the challenges in selecting different cooperating units, research on this topic remains limited. Thus, developing strategies for preparing structurally diverse organic eutectic materials is of great significance, both from the perspective of upgrading and improving existing methods and developing new ones. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide a novel three-dimensional organic eutectic material.

[0007] Another object of the present invention is to provide various methods for preparing the above-mentioned organic eutectic materials.

[0008] Another objective of this invention is to provide a method for controlling the crystal planes of the aforementioned organic comaterials.

[0009] The objective of this invention is achieved through the following technical solution.

[0010] An organic eutectic material is formed by the self-assembly of donor molecules and acceptor molecules through non-covalent bonds, wherein the donor molecule is a heteroatom-substituted adamantane organic molecule, and the acceptor molecule is a triazine ring organic molecule.

[0011] In the above technical solution, the heteroatom-substituted adamantane organic molecule in the organic eutectic material is one of hexamethylenetetramine, thioadamantane, and oxadamantane; the triazine ring structure organic molecule is one of cyanuric acid, melamine, and cyanuric chloride.

[0012] In the above technical solutions, the size of the nano-organic eutectic material is 100~1000 nm, and the size of the micro-organic eutectic material is 1~500 µm.

[0013] In the above technical solutions, the organic eutectic materials may form different crystal forms and morphologies due to different crystallization methods, including but not limited to: nano organic eutectic, micron polyhedral organic eutectic, micron octahedral organic eutectic, micron hexagonal organic eutectic, micron hollow organic eutectic, micron hexagonal pyramidal organic eutectic, etc.

[0014] A method for preparing a (nano)organic eutectic material includes the following steps:

[0015] The donor molecule and the acceptor molecule are dissolved in solvents (denoted as solution A and solution B), respectively. A and B are mixed to obtain a white turbid system. Centrifugation yields an organic eutectic material, which is a nano-organic eutectic material.

[0016] The molar ratio of the donor molecule to the acceptor molecule is 1:1.

[0017] In the above technical solution, the solvent can be water, ethanol, DMF, methanol, DMSO, or DMAC.

[0018] In the above technical solution, the reaction temperature is 0~100℃.

[0019] A method for preparing a (micron) organic eutectic material includes the following steps:

[0020] The acceptor molecule was dispersed in a solvent (denoted as dispersion A), dissolved by adding ammonia, and then a fatty aldehyde solution was added. After a period of time, a white turbid system was obtained. Centrifugation yielded an organic eutectic material, which is a micron-sized organic eutectic material.

[0021] In the above technical solution, the solvent can be water, acetonitrile, ethanol, DMF, methanol, DMSO, or DMAC.

[0022] In the above technical solution, the concentration of the dispersion is 0.01~0.5 mmol / mL.

[0023] In the above technical solution, the ratio of ammonia molecules to acceptor molecules is 3:1 based on the amount of matter.

[0024] In the above technical solution, the amount of fatty aldehyde added is 1~30 mmol.

[0025] In the above technical solution, the reaction temperature is 0~100℃.

[0026] A method for controlling the crystal planes of an organic comaterial, wherein, in the above technical solution, after adding ammonia, sodium formate, sodium acetate, sodium benzoate, formic acid or acetic acid can be introduced to change its crystal plane ratio.

[0027] This invention provides a method for preparing organic eutectic materials of different crystalline polyhedral structures.

[0028] The above-mentioned organic eutectic material is used in the field of photocatalysis, where it is used as an organic semiconductor for the photocatalytic preparation of hydrogen peroxide.

[0029] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0030] 1. The method described in this invention can complete the preparation of eutectic crystals in just 1 to 10 minutes under aqueous system conditions of 0 to 100°C; it avoids the limitations of traditional methods such as slow crystallization due to solvent evaporation rate control and lengthy preparation processes; it solves the dependence on organic solvents; and it has advantages such as being environmentally friendly and conducive to large-scale production.

[0031] 2. The organic eutectic materials based on eutectic engineering design in this invention can obtain hexahedral and octahedral structures with well-defined crystal faces and good crystallinity, thus achieving structural diversity in preparation.

[0032] 3. The method described in this invention controls crystallization through in-situ synthesis. This solves the solubility problem of acceptor molecules and allows for the control of structural diversity of the target product through the adjustment of experimental parameters. The entire preparation process is flexible and controllable. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the structure of an organic eutectic material.

[0034] Figure 2 These are scanning electron microscope images prepared in Example 1 of this invention.

[0035] Figure 3 This is a scanning electron microscope image prepared in Example 2 of the present invention.

[0036] Figure 4 This is a scanning electron microscope image prepared in Example 3 of the present invention.

[0037] Figure 5 This is a scanning electron microscope image prepared in Example 4 of the present invention.

[0038] Figure 6 This is the powder X-ray diffraction curve prepared in Example 2 of the present invention.

[0039] Figure 7 This is the powder X-ray diffraction curve prepared in Example 4 of this invention.

[0040] Figure 8 This is a scanning electron microscope image prepared in Example 5 of the present invention.

[0041] Figure 9 This is a scanning electron microscope image prepared in Example 6 of the present invention.

[0042] Figure 10 This is a scanning electron microscope image prepared in Example 7 of the present invention.

[0043] Figure 11 The photocatalytic synthesis performance of the organic cocrystals prepared in Examples 2 and 3 is shown.

[0044] Figure 12 This describes the photocatalytic synthesis of hydrogen peroxide using natural light from the organic eutectic prepared in Example 3. Detailed Implementation

[0045] The present invention will be further described below with reference to specific embodiments, but this does not limit the present invention in any way.

[0046] Unless otherwise specified, the instruments, reagents, and materials used in the following embodiments are all conventional instruments, reagents, and materials already available in the prior art and can be obtained through legitimate commercial channels. Unless otherwise specified, the experimental methods and detection methods used in the following embodiments are all conventional experimental methods and detection methods already available in the prior art. Example 1

[0047] Preparation of nano-organic eutectic

[0048] At room temperature, 0.177 g of trithiocyanate was dissolved in 20 mL of ethanol, and 0.140 g of hexamethylenetetramine (urotropine) was dissolved in 20 mL of deionized water. The two solutions were mixed and instantly turned into a white turbid system. After centrifugation, a white precipitate was obtained. The precipitate was washed three times with ethanol and deionized water, and then dried in an oven at 60°C.

[0049] The scanning electron microscope of the organic eutectic material in Example 1 is as follows: Figure 2 As shown in the figure, its size is in the nanometer range and its shape is octahedral. Example 2

[0050] Preparation of micron-sized octahedral organic eutectic

[0051] At room temperature, 0.177 g of trithiocyanate was dispersed in 10 mL of deionized water, 500 µL of ammonia was added, and then 2 mL of formaldehyde solution was added. After 30 s, the mixture became a white turbid system. After centrifugation, a white precipitate was obtained. The precipitate was washed three times with ethanol and deionized water, and then dried in an oven at 60 °C.

[0052] The scanning electron microscope of the organic eutectic material in Example 2 is as follows: Figure 3 As shown in the figure, its morphology is a micrometer-scale octahedron with a size between 2 and 10 µm; the powder X-ray diffraction curve ( Figure 6 It can be seen that it has high crystallinity, and its crystallization mode is trigonal with space group R3. The unit cell parameters are approximately a=9.7700, b=9.7700, c=25.7744, a=90, b=90, c=120. Its crystal structure is as follows. Figure 1 (Right) Trigonal unit cell shown. Example 3

[0053] Preparation of micron-sized hexahedral organic eutectic

[0054] At room temperature, 0.177 g of trithiocyanate was dispersed in 30 mL of deionized water, 500 µL of ammonia water was added, and then 2 mL of formaldehyde solution was added. After 1 min, the mixture became a white turbid system. After centrifugation, a white precipitate was obtained. The precipitate was washed three times with ethanol and deionized water, and then dried in an oven at 60 °C.

[0055] The scanning electron microscope of the organic eutectic material in Example 3 is as follows: Figure 4 As shown in the figure, its shape changes from an octahedron to a hexagon. Example 4

[0056] Preparation of micron-sized polyhedral organic eutectic

[0057] At room temperature, 0.177 g of trithiocyanate was dispersed in 10 mL of deionized water, and 500 µL of ammonia was added. The mixture was filtered through a 0.22 µm needle filter membrane, and then 500 µL of sodium formate solution (5.3 M) was added. Then, 200 µL of formaldehyde was added, and the mixture was placed in an 80 °C oven for 8 h. After centrifugation, transparent micron-sized organic eutectic was obtained. The eutectic was washed three times with ethanol and deionized water, and then dried in an oven at 60 °C.

[0058] The scanning electron microscope of the organic eutectic material in Example 4 is as follows: Figure 5 As shown in the figure, its morphology is polyhedral with a size >100 µm; its crystal structure and crystallinity can be determined by the powder X-ray diffraction curve (…). Figure 7 It was obtained by [method name missing]. It has high crystallinity, and its crystallization mode is hexagonal with space group P 163 mc, with unit cell parameters approximately a=9.6534, b=9.6534, c=16.438, a=90, b=90, c=120. Its crystal structure is as follows: Figure 1 (Left) Trigonal unit cell shown. Example 5

[0059] Large-scale preparation of micron-sized octahedral organic eutectics

[0060] At room temperature, 17.7 g of trithiocyanate was dispersed in 1000 mL of deionized water, 50 mL of ammonia water was added, and then 200 mL of formaldehyde solution was added. After 30 s, the mixture became a white turbid system. After centrifugation, a white precipitate was obtained. The precipitate was washed three times with ethanol and deionized water, and then dried in an oven at 60 °C.

[0061] The scanning electron microscope of the organic eutectic material in Example 5 is as follows: Figure 8 As shown. Example 6

[0062] Preparation of micron-sized hollow organic eutectic

[0063] At room temperature, 0.177 g of trithiocyanate was dispersed in 10 mL of methanol, 500 µL of ammonia water was added, and then 2 mL of formaldehyde solution was added. After 2 min, the mixture became a white turbid system. The precipitate was obtained by centrifugation and washed three times with ethanol and deionized water.

[0064] The scanning electron microscope of the organic eutectic material in Example 6 is as follows: Figure 9 As shown in the figure, its shape has changed to a hollowed-out octahedron. Example 7

[0065] Preparation of micron-sized hexagonal pyramidal organic eutectic

[0066] At room temperature, 0.177 g of trithiocyanate was dispersed in 10 mL of deionized water, 500 µL of ammonia and 3 mL of sodium formate solution (5.3 M) were added, followed by 2 mL of formaldehyde solution. After 2 min, the mixture became a white turbid system. The precipitate was obtained by centrifugation and washed three times with ethanol and deionized water.

[0067] The scanning electron microscope of the organic eutectic material in Example 7 is as follows: Figure 10 As shown in the figure, its shape has changed to a hexagonal pyramid. Example 8

[0068] 15 mg of the micron-sized octahedral organic eutectic prepared in Example 2 was dispersed in 35 mL of benzyl alcohol / water solution (v / v: 1 / 6). The mixture was stirred with air bubbles in the dark for 30 min. A photocatalytic reaction was performed using a 300 W xenon lamp as the light source (λ > 300 nm and λ > 400 nm). The reaction solution was collected, and the H2O2 concentration was determined using a colorimetric method (potassium titanium oxalate was used as the colorimetric reagent; 1 mL of the reaction solution, 1 mL of 3 M sulfuric acid, and 1 mL of 0.05 M titanium oxalate solution were used for the colorimetric reaction, and the absorbance of the colorimetric solution was measured using a UV-Vis spectrophotometer). The results are as follows: Figure 11As shown, the hydrogen peroxide yield reached 25.15 mmol g in the wavelength range of λ > 400 nm. -1 h -1 The apparent quantum efficiency at 400 nm wavelength is 11.3%; in the wavelength range of λ > 300 nm, the hydrogen peroxide yield reaches 37.13 mmol g. -1 h -1 . Example 9

[0069] 15 mg of the micron-sized hexahedral organic eutectic prepared in Example 3 was dispersed in 35 mL of benzyl alcohol / water solution (v / v: 1 / 6). The mixture was stirred with air bubbles in the dark for 30 min. A photocatalytic reaction (λ > 300 nm and λ > 400 nm) was performed using a 300 W xenon lamp as the light source. The reaction solution was collected, and the H2O2 concentration was determined using a colorimetric method (potassium titanium oxalate was used as the colorimetric reagent; 1 mL of the reaction solution, 1 mL of 3 M sulfuric acid, and 1 mL of 0.05 M titanium oxalate solution were used for the colorimetric reaction, and the absorbance of the colorimetric solution was measured using a UV-Vis spectrophotometer). The results are as follows: Figure 11 As shown, the hydrogen peroxide yield reached 27.35 mmol g in the wavelength range of λ > 400 nm. -1 h -1 The apparent quantum efficiency at 400 nm wavelength is 17.3%; in the wavelength range of λ > 300 nm, the hydrogen peroxide yield reaches 45.27 mmol g. -1 h -1 . Example 10

[0070] 15 mg of the micron-sized hexahedral organic eutectic prepared in Example 3 was dispersed in 35 mL of benzyl alcohol / water solution (v / v: 1 / 6). The mixture was stirred with air bubbles in the dark for 30 min. A photocatalytic reaction was carried out using outdoor sunlight as the light source. The reaction solution was collected and analyzed. The H2O2 concentration was determined using a colorimetric method (potassium titanium oxalate was used as the colorimetric agent; 1 mL of the reaction solution, 1 mL of 3 M sulfuric acid, and 1 mL of 0.05 M titanium oxalate solution were used for the colorimetric reaction, and the absorbance of the colorimetric solution was measured using a UV-Vis spectrophotometer). The results are as follows: Figure 12 As shown, under natural light, without stirring or continuous air introduction, the hydrogen peroxide yield still reaches 26.95 mmol g. -1 h -1 This indicates that the material has high practical production value.

Claims

1. A three-dimensional organic eutectic material, characterized in that, It is formed by the self-assembly of a donor molecule and an acceptor molecule through non-covalent bonds; the donor molecule is a heteroatom-substituted adamantane organic molecule, and the acceptor molecule is a triazine ring organic molecule; the heteroatom-substituted adamantane organic molecule is one of hexamethylenetetramine, thioadamantane, and oxadiazine; the triazine ring organic molecule is one of cyanuric acid, melamine, and cyanuric chloride. The method for preparing the organic eutectic material includes the following steps: dissolving the donor molecule and the acceptor molecule in a solvent, respectively, and denoting them as solution A and solution B; mixing solution A and solution B to obtain a white turbid system; and centrifuging to obtain the organic eutectic material.

2. A three-dimensional organic eutectic material, characterized in that, It is formed by the self-assembly of a donor molecule and an acceptor molecule through non-covalent bonds; the donor molecule is a heteroatom-substituted adamantane organic molecule, and the acceptor molecule is a triazine ring organic molecule; the heteroatom-substituted adamantane organic molecule is one of hexamethylenetetramine, thioadamantane, and oxadiazine; the triazine ring organic molecule is one of cyanuric acid, melamine, and cyanuric chloride. The method for preparing the organic eutectic material includes the following steps: dispersing the acceptor molecule in a dispersion solvent, denoted as dispersion A; adding ammonia water to dissolve it, then adding a fatty aldehyde solution to obtain a white turbid system, and centrifuging to obtain the organic eutectic material.

3. The organic eutectic material according to claim 1 or 2, characterized in that, The organic eutectic material is a nano-organic eutectic material or a micro-organic eutectic material. The size of the nano-organic eutectic is 100~1000 nm, and the size of the micro-organic eutectic is 1~500 µm.

4. The organic eutectic material according to claim 1 or 2, characterized in that, The organic eutectic material has the following crystal forms: nano organic eutectic, micron polyhedral organic eutectic, and micron hollow organic eutectic; the micron polyhedral organic eutectic is selected from micron octahedral organic eutectic, micron hexagonal organic eutectic, and micron hexagonal pyramidal organic eutectic.

5. The organic eutectic material according to claim 1, characterized in that, The solvent is water, ethanol, DMF, methanol, DMSO, or DMAC; the reaction temperature is 0~100℃.

6. The organic eutectic material according to claim 5, characterized in that: The molar ratio of the donor molecule to the acceptor molecule is 1:

1.

7. The organic eutectic material according to claim 2, characterized in that, The dispersion solvent is water, acetonitrile, ethanol, DMF, methanol, DMSO, or DMAC; the concentration of dispersion A is 0.001~0.5 mmol / mL; the molar ratio of ammonia molecules to acceptor molecules is 3:1; the amount of aliphatic aldehyde added is 1~30 mmol; and the reaction temperature is 0~100℃.

8. The organic eutectic material according to claim 2, characterized in that: After adding ammonia, add sodium formate, sodium acetate, sodium benzoate, formic acid, or acetic acid.

9. The application of the organic eutectic material according to claim 1, characterized in that: The organic eutectic material is used as an organic semiconductor for the photocatalytic preparation of hydrogen peroxide.

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