Metalloporphyrin nanocatalyst, preparation method and application thereof

Abstract

The present application relates to a kind of metal porphyrin nanocatalyst and its preparation method and application, the structure of the catalyst is: preparation method is: 5,10,15,20-tetra (p-hydroxyphenyl) copper porphyrin and 2,4,6-trichloro-1,3,5-triazine are placed in solvent and dissolved, after mixing uniformly, triethylamine is added to reaction;After reaction, precipitate is separated by centrifugation, after washing, drying, copper porphyrin polytriazine nanosphere, i.e. metal porphyrin nanocatalyst is obtained;It is applied to simulate polyphenol oxidase.Compared with prior art, the present application provides a new type of metal porphyrin nanocatalyst, i.e. copper porphyrin polytriazine nanosphere catalyst, its preparation method process is mild and simple, environmental protection and economy, the copper porphyrin polytriazine nanosphere prepared has high catalytic activity, post-processing is simple, easy to recycle and reuse, has strong application potential in catalysis, energy, environment and other aspects.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of functional catalysts, in particular to a metal porphyrin nano-catalyst and a preparation method and application thereof. BACKGROUND

[0002] Porphyrin and its derivatives are an important class of life substances widely existing in nature, which is a planar ring 18-electron conjugated system structure connected by four sp 2 carbon atoms. The four nitrogen atoms of the pyrrole ring can be complexed with almost all metal ions in the periodic table to form stable metal porphyrins. The dispersion of copper ions in the molecular structure can form stable copper-porphyrin complexes, which have high thermal stability and light stability, can improve the electron transfer rate and enhance the catalytic performance. Copper has good catalytic activity in many catalytic reactions, high stability and various reaction selectivity, which can promote oxidation, reduction, carbonylation and hydroxylation and other reactions, and is widely used in organic synthesis, energy conversion and other fields. Moreover, copper is a non-noble metal, which is relatively abundant in resources and low in cost, and is cheap and easy to obtain. Compared with noble metal catalysts, copper catalysts have advantages in environmental friendliness and have less impact on the environment.

[0003] The preparation and catalytic application of copper-porphyrin complexes have always been a focus of attention. Chinese patent CN202010337237.4 uses monomeric copper porphyrin as a catalyst for the polymerization of ε-caprolactone, which has the advantages of high catalytic activity, mild conditions, simple process, etc.; Chinese patent CN201811467562.1 uses copper porphyrin as a catalyst to promote the catalytic oxidation of naphthenes, which has the advantages of high product selectivity, low reaction temperature, less catalyst usage, green and environmentally friendly, simple operation, no use of organic solvents, etc. However, monomeric metalloporphyrin catalytic systems are extremely unstable and can easily be deactivated by external conditions such as stirring and high temperature during the reaction. Moreover, they can easily decompose and self-oxidize as the reaction proceeds, making it difficult to achieve reuse as a homogeneous catalyst. Chinese patent CN201910223130.4 provides a preparation method and application of a porphyrin-stable copper nanocatalyst. The four hydroxyl groups on the periphery of the porphyrin macrocycle and the steric factor of the macrocycle can effectively control the aggregation of copper nanoparticles, showing better charge transfer dynamics and good electronic media. However, sodium borohydride is used to reduce copper ions to copper nanoparticles in the process, which requires strict control of reaction conditions to maintain safe and stable operation. Chinese patent CN201710378008.5 discloses a method for catalytically synthesizing a four-amino-phenyl-bridged metalloporphyrin conjugated porous polymer using a cheap, efficient, and green catalytic system (copper salt / amino acid) as a catalyst for the catalytic oxidation of cyclopentanone, cyclohexanone, and their derivatives to form lactones; Chinese patent CN202210139626.5 provides a copper-based nanoparticle and iron porphyrin nanosheet composite nanoscale enzyme and a preparation method, which can solve the problem of existing technology that is limited to the preparation of noble metal-based enzyme-mimicking composite nanomaterials; Chinese patent CN201210122025.X relates to the preparation and catalytic application of a metal-porphyrin polymer material. The catalyst has mild reaction conditions and no pollution, and is used for high conversion of sulfides, aromatic hydrocarbons, and high selectivity of sulfoxides. The catalyst can be recycled by simple filtration.

[0004] Immobilizing copper-porphyrin complexes and regulating the interaction between metal ions and reactants can increase their surface area, improve the availability of copper ions, and thus improve the efficiency and selectivity of catalytic reactions. Immobilized copper-porphyrin complex derivatives can be easily separated and recycled, facilitating subsequent reuse and reducing catalyst loss. By choosing the appropriate immobilization method, the hydrophilicity or hydrophobicity of the metalloporphyrin immobilized system can be regulated to make it suitable for different catalytic reactions and solvent systems, thereby expanding the application range of metalloporphyrins. In the field of materials, metalloporphyrins and their derivatives are widely used in the preparation of functional materials such as organic optoelectronic materials, sensors, and catalysts. Their unique structure and properties have brought broad prospects and opportunities for exploration and application in this field. Therefore, it is necessary to develop a new type of functional catalyst with high catalytic activity.

[0005] In addition, natural enzymes have high catalytic efficiency and mild reaction conditions, but the stability of natural enzymes is poor, easy to be inactivated, not easy to be preserved, and high in cost, which limits its application. For example, polyphenol oxidase is a specific copper metalloenzyme encoded by nuclear genes, which is widely distributed in microorganisms, plants and animals, and plays an important role in the growth and metabolism system and signal transmission of organisms. At present, the research in the field of biological medicine shows that it has potential preventive and therapeutic effect on Alzheimer's disease in human. Therefore, it is a very challenging task to find a material with both enzyme activity and high stability to carry out chemical simulation of polyphenol oxidase. SUMMARY

[0006] The purpose of the present application is to provide a metal porphyrin nanocatalyst with environmental protection, low price and high catalytic activity, a preparation method thereof and an application of simulating polyphenol oxidase.

[0007] The purpose of the present application can be achieved by the following technical solutions.

[0008] One of the purposes of the present application is a metal porphyrin nanocatalyst, and the structure of the catalyst is as follows:

[0009]

[0010] The second purpose of the present application is a preparation method of the metal porphyrin nanocatalyst, and the method comprises the following steps:

[0011] 5,10,15,20-tetra (p-hydroxyphenyl) copper porphyrin and 2,4,6-trichloro-1,3,5-triazine are placed in a solvent to be dissolved, and then triethylamine is added after being uniformly mixed; after the reaction is completed, the precipitate is separated by centrifugation, and the precipitate is washed and dried to obtain copper porphyrin polytriazine nanomicrospheres, i.e. the metal porphyrin nanocatalyst.

[0012] In an embodiment of the present application, the molar ratio of 5,10,15,20-tetra (p-hydroxyphenyl) copper porphyrin to 2,4,6-trichloro-1,3,5-triazine is 1:1-5; preferably, the molar ratio of 5,10,15,20-tetra (p-hydroxyphenyl) copper porphyrin to 2,4,6-trichloro-1,3,5-triazine is 1:2.

[0013] In an embodiment of the present application, the solvent is acetonitrile; the ratio of 5,10,15,20-tetra (p-hydroxyphenyl) copper porphyrin to acetonitrile is 1 mmol:0.5-3 L; preferably, the ratio of 5,10,15,20-tetra (p-hydroxyphenyl) copper porphyrin to acetonitrile is 1 mmol:2 L.

[0014] In one embodiment of the present application, the mixing method is ultrasonic mixing, and the ultrasonic frequency is 20-60 kHz, preferably 40 kHz.

[0015] In one embodiment of the present application, the triethylamine is anhydrous and oxygen-free treated triethylamine, and the ratio of 5,10,15,20-tetra(p-hydroxyphenyl) copper porphyrin to triethylamine is 1 mmol: 30-100 mL; preferably, the ratio of 5,10,15,20-tetra(p-hydroxyphenyl) copper porphyrin to triethylamine is 1 mmol: 66 mL.

[0016] In one embodiment of the present application, the reaction temperature is 20-50℃, and the reaction time is 10-60 min; preferably, the reaction temperature is 25℃, and the reaction time is 30 min.

[0017] In one embodiment of the present application, the centrifugal speed is 3000-10000 rpm; preferably, the centrifugal speed is 9000 rpm; and the centrifugal time is 5-35 min; preferably, the centrifugal time is 15 min.

[0018] In one embodiment of the present application, the washing solution used in the precipitation washing is acetonitrile; the drying method is vacuum drying; the acetonitrile washing times are 1-5 times; preferably, the acetonitrile washing times are 3 times; the vacuum drying temperature is 25-60℃, and the vacuum drying time is 4-10 h; preferably, the vacuum drying temperature is 40℃, and the vacuum drying time is 6 h.

[0019] The third object of the present application is the application of the metal porphyrin nanocatalyst as described above, characterized in that the catalyst is applied to simulate polyphenol oxidase. The catalytic substrates of polyphenol oxidase are various, such as catechol, 3,5-di-tert-butylcatechol, dopamine, adrenaline, etc. In one embodiment of the present application, the catalytic substrate is catechol.

[0020] The four hydroxyl groups outside the phenyl ring of the porphyrin macrocycle and the steric factor of the macrocycle in the present application can effectively anchor copper ions, so that the catalyst exhibits better charge transfer driving force and good catalysis. In addition, the nanocatalyst synthesized in the present application has a relatively uniform, narrow particle size distribution, and good particle morphology. The preparation method in the present application is simple, and the conditions are mild; the reaction temperature and time are controllable, and the operation is simple; the product is water-insoluble, can be recycled and reused, and reduces the cost.

[0021] Compared with existing technologies, this invention provides a novel metal porphyrin nanocatalyst, namely copper porphyrin polytriazine nanosphere catalyst. Its preparation method is mild, simple, environmentally friendly and economical. The prepared copper porphyrin polytriazine nanospheres have high catalytic activity, simple post-processing, and are easy to recycle and reuse. It has strong application potential in catalysis, energy and environment. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the synthesis route of copper porphyrin polytriazine nanospheres in this invention;

[0023] Figure 2 The image shows a scanning electron microscope (SEM) image of the copper porphyrin polytriazine nanospheres prepared in Example 1.

[0024] Figure 3 X-ray photoelectron spectroscopy (XPS) of the copper porphyrin polytriazine nanospheres prepared in Example 1;

[0025] Figure 4 The Fourier transform infrared spectrum (FT-IR) of the copper porphyrin polytriazine nanospheres prepared in Example 1;

[0026] Figure 5 The image shows the UV spectrum of catechol catalyzed by polyphenol oxidase simulating polyphenol oxidase in the copper porphyrin polytriazine nanospheres prepared in Example 1 (the product is catechol diquinone). Detailed Implementation

[0027] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are implemented based on the technical solution of the present invention, providing detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0028] The 5,10,15,20-tetra(p-hydroxyphenyl)porphyrin and 5,10,15,20-tetra(p-hydroxyphenyl)copper porphyrin used in the following examples were prepared according to the literature Li-Na Zhu, Shu-Juan Zhao, Bin Wu, et al. A new cationicporphyrin derivative (TMPipEOPP) with large side arm substituents: a highly selective G-quadruplex optical probe, PLoS ONE, 2012, 7(5):e35586; Niu Jinfen, Yao Binghua, Liu Tingting. Synthesis of tetrahydroxyphenyl metalloporphyrin (MTHPP) / TiO2 and its photocatalytic activity, Molecular Catalysis, 2011, 25(05):435-441. The reaction chemical equations are as follows:

[0029]

[0030] Example 1

[0031] 5,10,15,20-tetra(p-hydroxyphenyl) copper porphyrin (54.5 mg, 0.075 mmol) and 2,4,6-trichloro-1,3,5-triazine (28.8 mg, 0.150 mmol) were added into a 250 mL flask, 150 mL acetonitrile was added, and the mixture was uniformly mixed by ultrasonic mixing at 40 kHz. 5 mL triethylamine was added, and the mixture was reacted at 25°C for 30 min. The mixture was centrifuged at 9000 rpm for 15 min, washed with acetonitrile 3 times, and dried at 40°C under vacuum for 6 h to obtain copper porphyrin polytriazine nanomicrospheres.

[0032] Figure 1 The synthesis route of the novel copper porphyrin nanocatalyst (copper porphyrin polytriazine nanomicrospheres) in the present application is shown in the figure. In the polymerization process, because the molecular size of 5,10,15,20-tetra(p-hydroxyphenyl) copper porphyrin is much larger than that of 2,4,6-trichloro-1,3,5-triazine, there is steric hindrance during condensation, and therefore, only part of the Cl atoms in 2,4,6-trichloro-1,3,5-triazine will be replaced by 5,10,15,20-tetra(p-hydroxyphenyl) copper porphyrin molecules.

[0033] Figure 2 The scanning electron microscope (SEM) image of the copper porphyrin polytriazine nanomicrospheres prepared in Example 1 is shown in the figure, (A) magnification 10000 times; (B) magnification 50000 times. As can be seen from the figure, the obtained tetrahydroxyphenyl copper porphyrin cyanuric chloride nanomicrospheres are uniformly dispersed, and the particle size is relatively small, and the morphology is mainly spherical.

[0034] Figure 3 The X-ray photoelectron spectroscopy (XPS) of the copper porphyrin polytriazine nanomicrospheres prepared in Example 1 is shown in the figure. The spectrum shows that the copper porphyrin polytriazine nanomicrospheres are mainly composed of C, N, O and Cu elements. Among them, Cu 2p 3 / 2 is located at 934.2 eV, Cu2p 1 / 2 is located at 953.7 eV, and obvious satellite peaks appear at 943.5 eV and 963.5 eV, respectively, indicating that the Cu element in the copper porphyrin polytriazine nanomicrospheres is in +2 valence state.

[0035] Figure 4 The infrared spectrum (FT-IR) of the copper porphyrin polytriazine nanomicrospheres prepared in Example 1 is shown in the figure. In the spectrum, 1650-1400 cm -1 belongs to the stretching vibration peak of C=C and C=N, 1346 cm -1 is the characteristic peak of aromatic C-N stretching vibration, and 1205 cm-1 The absorption peak at 1001 cm-1 is the stretching vibration of the aromatic ether C-O. -1 The signal at 814 cm-1 is the oxidation state identification band specific to the metalloporphyrin. -1 The peak near 800 cm-1 is the characteristic absorption peak of the triazine ring.

[0036] Figure 5 The copper porphyrin polytriazine nanomicrosphere prepared in Example 1 was used to simulate polyphenol oxidase to catalyze catechol to produce benzoquinone, and the UV spectrum of benzoquinone was obtained. The copper porphyrin polytriazine nanomicrosphere obtained by the application was used to simulate polyphenol oxidase to catalyze catechol. The test principle is that catechol is oxidized to benzoquinone after the addition of the catalyst, and because the molar absorption coefficient of the quinone product is small, it is not easy to detect and observe at low concentration. Therefore, 3-methyl-2-benzothiazole hydrazone (MBTH) is often added. The complex of MBTH and the oxidation product quinone has a peak at about 550 nm (the molar absorption coefficient is greatly improved), which is conducive to tracking the reaction. The experimental scheme is as follows: 0.01 g of catechol is dissolved in 100 mL of deionized water and ultrasonically dissolved; 5 mg of copper porphyrin polytriazine nanomicrosphere is dissolved in 10 mL of dimethyl sulfoxide, and 20 mg of MBTH is added; 2.9 mL of catechol solution in step one is taken in a cuvette, and 0.1 mL of catalyst solution in step two is added. From 550 nm, it can be seen that with the extension of time, the absorbance gradually increases, and it can be concluded that the copper porphyrin polytriazine nanomicrosphere can simulate polyphenol oxidase to catalyze catechol.

[0037] Example 2

[0038] 5,10,15,20-tetra (p-hydroxyphenyl) copper porphyrin (54.5 mg, 0.075 mmol) and 2,4,6-trichloro-1,3,5-triazine (13.83 mg, 0.075 mmol) were added to a 250 mL flask, 37.5 mL of acetonitrile was added, and ultrasonic mixing was performed at 60 kHz. 7.5 mL of triethylamine was added, and the reaction was carried out at 20°C for 60 min. The centrifugal speed was 3000 rpm, the centrifugal time was 35 min, and the acetonitrile was washed once. The vacuum drying was carried out at 25°C for 10 h, and the copper porphyrin polytriazine nanomicrosphere was obtained.

[0039] Example 3

[0040] 5,10,15,20-tetra (p-hydroxyphenyl) copper porphyrin (54.5 mg, 0.075 mmol) and 2,4,6-trichloro-1,3,5-triazine (43.22 mg, 0.225 mmol) were added into a 250 mL flask, 225 mL acetonitrile was added, ultrasonic mixing was carried out at 20 kHz, 2.25 mL triethylamine was added, and the reaction was carried out at 50°C for 10 min. Centrifugation was carried out at 10000 rpm for 5 min, acetonitrile was used for washing 3 times, and vacuum drying was carried out at 60°C for 4 h to obtain copper porphyrin polytriazine nanomicrospheres.

[0041] Example 4

[0042] 5,10,15,20-tetra (p-hydroxyphenyl) copper porphyrin (109 mg, 0.15 mmol) and 2,4,6-trichloro-1,3,5-triazine (86.44 mg, 0.45 mmol) were added into a 250 mL flask, 350 mL acetonitrile was added, ultrasonic mixing was carried out at 50 kHz, 12 mL triethylamine was added, and the reaction was carried out at 35°C for 30 min. Centrifugation was carried out at 10000 rpm for 10 min, acetonitrile was used for washing 5 times, and vacuum drying was carried out at 60°C for 6 h to obtain copper porphyrin polytriazine nanomicrospheres.

[0043] The above only describes the preferred embodiments of the present application and is not intended to limit the present application in other forms. Any person skilled in the art can modify or change the above disclosed technical content into equivalent embodiments with equivalent changes. However, any simple modification, equivalent change and modification of the above embodiments made according to the technical essence of the present application without departing from the technical scheme of the present application still falls within the protection scope of the present application.

Claims

1. A metalloporphyrin nanocatalyst for mimicking polyphenol oxidase, characterized in that, The structure of the catalyst is as follows: ； The preparation method of the metal porphyrin nanocatalyst comprises the following steps: 5, 10, 15, 20-tetra (p-hydroxyphenyl) copper porphyrin and 2, 4, 6-trichloro-1, 3, 5-triazine are dissolved in a solvent, and after being mixed uniformly, triethylamine is added for reaction; after the reaction is completed, the precipitate is separated by centrifugation, and after washing and drying, copper porphyrin polytriazine nanomicrospheres, i.e. metal porphyrin nanocatalyst, are obtained.

2. The metalloporphyrin nanocatalyst for mimicking polyphenol oxidase according to claim 1, characterized in that, The molar ratio of the 5, 10, 15, 20-tetra (p-hydroxyphenyl) copper porphyrin to the 2, 4, 6-trichloro-1, 3, 5-triazine is 1: 1~5.

3. The metalloporphyrin nanocatalyst for mimicking polyphenol oxidase according to claim 1, characterized in that, The solvent is acetonitrile; the ratio of the 5, 10, 15, 20-tetra (p-hydroxyphenyl) copper porphyrin to the acetonitrile is 1 mmol: 0.5~3 L.

4. The metalloporphyrin nanocatalyst for mimicking polyphenol oxidase according to claim 1, characterized in that, The uniform mixing method is ultrasonic mixing, and the ultrasonic frequency is 20~60 kHz.

5. The metalloporphyrin nanocatalyst for mimicking polyphenol oxidase according to claim 1, characterized in that, The triethylamine is anhydrous and oxygen-free treated triethylamine, and the ratio of the 5, 10, 15, 20-tetra (p-hydroxyphenyl) copper porphyrin to the triethylamine is 1 mmol: 30~100 mL.

6. The metalloporphyrin nanocatalyst for mimicking polyphenol oxidase according to claim 1, characterized in that, The reaction temperature is 20~50℃, and the reaction time is 10~60 min.

7. The metalloporphyrin nanocatalyst for mimicking the activity of polyphenol oxidase according to claim 1, wherein, The centrifugal speed is 3000~10000 rpm; and the centrifugal time is 5~35 min.

8. The metalloporphyrin nanocatalyst for mimicking polyphenol oxidase according to claim 1, characterized in that, The washing solution used for washing the precipitate is acetonitrile; and the drying method is vacuum drying. The acetonitrile washing times are 1~5 times; and the vacuum drying temperature is 25~60℃, and the vacuum drying time is 4~10 h.

9. Use of a metalloporphyrin nanocatalyst for mimicking a polyphenol oxidase according to any one of claims 1 to 8, characterized in that, The catalyst is applied to simulate polyphenol oxidase.

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