Trithiophene-based covalent triazine framework photocatalyst as well as preparation method and application thereof
By preparing the triazine framework photocatalyst 3S-CTF based on triazine, the shortcomings of high temperature and high oxidant in the existing technology are solved, and the efficient synthesis of bis(imidazo[1,2-α]pyridin-3-yl) selenide at room temperature is realized. The catalyst can be recycled, reducing production costs and meeting the requirements of green chemistry.
Patent Information
- Application Number
- CN202511282970.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-09
- Publication Date
- 2025-12-16
AI Technical Summary
Existing techniques for preparing bis(imidazo[1,2-α]pyridin-3-yl)selenide require high temperatures and strong oxidants, and also suffer from problems such as easy agglomeration of selenium powder and difficulty in post-processing.
Using tris(thiophene-2,6-dicarboxaldehyde) as a raw material, combined with a nitrogen source and a catalyst, a covalent triazine framework photocatalyst based on tris(thiophene) was prepared by condensation reaction. The bis(imidazo[1,2-α]pyridin-3-yl)selenide was then synthesized by visible light catalysis at room temperature. The catalyst is recyclable.
The efficient synthesis of bis(imidazo[1,2-α]pyridin-3-yl)selenide at room temperature was achieved. The catalyst exhibited good stability and high catalytic activity, reducing production costs and meeting the energy-saving and environmental protection requirements of green chemistry.
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Abstract
Description
TECHNICAL FIELD
[0001] The present application belongs to the technical field of photocatalysis, and particularly relates to a covalent triazine frame photocatalyst. BACKGROUND
[0002] Light, as a clean and renewable energy, has been explored for driving organic reactions for over a century. Nowadays, under the background of increasingly urgent demand for energy security and environmental protection worldwide, the development of new porous organic polymers with high catalytic activity has become a frontier focus in the fields of materials and chemistry. Such materials include carbon nitride, conjugated microporous polymers (CMPs), amorphous porous aromatic frameworks (PAFs), hypercrosslinked polymers (HCPs), covalent triazine frameworks (CTFs) and covalent organic frameworks (COFs), etc. They have been widely and deeply explored in many fields due to their excellent stability and controllability. Among them, covalent triazine frameworks (CTFs) are particularly attractive. The unique features of CTFs are easy-to-access carbon active sites, precisely controllable pore structures, and flexible and adjustable carbon-nitrogen atom ratios, which make them extremely potential photocatalyst candidate materials. Therefore, the development of efficient photocatalysts based on CTFs has become a core hotspot and important direction in the related research field in recent years.
[0003] Imidazo[1,2-a]pyridine is an important class of nitrogen-containing fused heterocyclic bioactive compounds, which have been widely used in medicinal chemistry and material science. Many drugs and clinical candidates, such as Zolpidem, Alpidem, etc., contain imidazo[1,2-a]pyridine skeleton. Among them, bis(imidazo[1,2-a]pyridin-3-yl) selenide with selenium substituent has potential biological activities such as antioxidant activity, anticancer activity, etc., so its synthesis method has attracted widespread attention. An effective method for synthesizing bis(imidazo[1,2-a]pyridin-3-yl) selenide is to use imidazo[1,2-a]pyridine and selenium powder to carry out a tandem double C-H selenylation reaction in the presence of a transition metal catalyst (such as Cu, etc.). For example, in 2018 and 2020, Yasuike group and others developed an efficient method: under aerobic conditions, at 130℃, CuI (10 mol%) coordinates with 1,10-phenanthroline (10 mol%) to catalyze the double C-H selenylation reaction of imidazo[1,2-a]pyridine and selenium powder (Synthesis, 2018, 50, 2200-2210, DOI: 10.1055 / s-0036-1591972; Beilstein J. Org. Chem., 2020, 16, 1075-1083, DOI: 10.3762 / bjoc.16.94). However, the proposed scheme, although efficient, has the disadvantages of requiring a transition metal catalyst and high reaction temperature, and selenium powder is easy to agglomerate and difficult to handle. In addition, selenocyanate can be used as an effective selenium source to synthesize bis(imidazo[1,2-a]pyridin-3-yl) selenide, which effectively avoids the above disadvantages of selenium powder. For example, in 2020, Song group and others published a paper reporting an efficient method for iodine-catalyzed synthesis of bis(imidazo[1,2-a]pyridin-3-yl) selenide using potassium selenocyanate (KSeCN) as a selenium source (J. Org. Chem. 2020, 85, 9106-9116, DOI: 10.1021 / acs.joc.0c01035). Although this method can effectively avoid the disadvantages of using selenium powder as a selenium source and does not use a transition metal catalyst, the method still requires high reaction temperature (as high as 110℃) and strong oxidant (PhI(OAc)2). SUMMARY
[0004] In view of the technical problems of high temperature and strong oxidant in the reaction system for preparing bis(imidazo[1,2-a]pyridin-3-yl) selenide, the application provides a covalent triazine framework photocatalyst based on terthiophene and a preparation method and application thereof. A CTF photocatalyst (named as 3S-CTF) with stable structure and high catalytic activity is constructed by using terthiophene-2,6-dicarboxaldehyde as a raw material, and the photocatalyst is applied to the photocatalytic synthesis of bis(imidazo[1,2-a]pyridin-3-yl) selenide at room temperature. After the reaction, the photocatalyst can be recycled, and a simple and efficient new method for synthesizing bis(imidazo[1,2-a]pyridin-3-yl) selenide is provided.
[0005] In order to achieve the above-mentioned purpose, the technical scheme of the application is as follows:
[0006] A covalent triazine framework photocatalyst based on terthiophene, wherein the covalent triazine framework photocatalyst is composed of a plurality of repeated structural units, and the structural formula of the structural unit is shown in the following formula I, wherein "--" represents an omitted repeated structural unit.
[0007]
[0008] A preparation method of a covalent triazine framework photocatalyst, comprising the following steps: uniformly mixing terthiophene-2,6-dicarboxaldehyde, a nitrogen source, a catalyst and a solvent A to prepare a reaction solution A, then performing a condensation reaction, and obtaining the covalent triazine framework photocatalyst based on terthiophene after the reaction.
[0009] The molar ratio of the terthiophene-2,6-dicarboxaldehyde, the nitrogen source and the catalyst is 1:(1-3):(0.1-1); and the solvent A is o-dichlorobenzene, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide or 1,4-dioxane.
[0010] The nitrogen source is ammonium chloride, ammonium bromide or ammonium iodide.
[0011] The catalyst is ferric trichloride, iron acetate or aluminum trichloride.
[0012] The concentration of the terthiophene-2,6-dicarboxaldehyde in the reaction solution A is 0.02-0.2 mol / L.
[0013] The condensation reaction is performed at a temperature of 40-160 DEG C for 1-4 days.
[0014] The application of the covalent triazine framework photocatalyst based on terthiophene in the catalytic synthesis of bis(imidazo[1,2-a]pyridin-3-yl) selenide.
[0015] The step of the reaction for synthesizing the bis(imidazo[1,2-a]pyridin-3-yl) selenide is: mixing a covalent triazine frame photocatalyst based on tri-thiophene, an imidazo[1,2-a]pyridine derivative, elemental iodine, potassium selenocyanate and a solvent B to prepare a reaction solution B, and performing the reaction under visible light irradiation.
[0016] The covalent triazine frame photocatalyst based on tri-thiophene is 1-100 mg / mL based on the amount of the solvent B added; the concentration of the imidazo[1,2-a]pyridine derivative in the reaction solution B is 0.1-1 mol / L, the concentration of the elemental iodine is 0.02-0.2 mol / L, and the concentration of the potassium selenocyanate is 0.2-2 mol / L; and the solvent B is tetrahydrofuran.
[0017] The beneficial effects of the present application are:
[0018] (1) The 3S-CTF catalyst developed in the present application can be prepared by a conventional solvothermal process, and the whole process does not require a strict anhydrous and anaerobic environment. This preparation method is not only simple to operate, but also easy to realize large-scale batch production, and can effectively reduce the production cost. This breakthrough provides a new choice for the field of photocatalyst materials, and further expands the application boundary and practical value of CTFs materials.
[0019] (2) The tri-thiophene group in the molecular structure of the 3S-CTF has excellent conjugation characteristics and electron-rich properties, which can form an efficient “electron donor-acceptor” system with the triazine group in the frame, thereby significantly broadening the absorption range of the material to visible light and optimizing the band gap structure. This property can effectively reduce the recombination rate of photo-generated carriers, improve the charge separation efficiency and electron migration rate, and ultimately significantly enhance the photocatalytic activity of the 3S-CTF. Experimental data confirms that the photocatalytic performance of the prepared 3S-CTF is significantly better than that of the 0S-CTF which is not modified by a thiophene group, and in the reaction of photocatalytic synthesis of bis(imidazo[1,2-a]pyridin-3-yl) selenide, the catalytic activity of the 3S-CTF reaches 2.12 times that of the 0S-CTF.
[0020] (3) The 3S-CTF photocatalyst constructed in the present application has excellent stability and can be used repeatedly. After repeated cycle experiments, the crystal structure and catalytic activity of the catalyst do not show obvious attenuation.
[0021] (4) As a new type of photocatalytic material, the 3S-CTF catalytic reaction can be carried out at room temperature without additional heating, and the reaction can be started only by visible light irradiation. It has simple requirements for the catalytic environment, does not require transition metals, and the oxidizing agent only needs oxygen in the air. This catalytic process has the advantages of energy saving, environmental protection and safety, and conforms to the development trend of green chemistry. BRIEF DESCRIPTION OF DRAWINGS
[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the accompanying drawings needed to be used in the embodiments or prior art description will be briefly introduced as follows. Obviously, the accompanying drawings in the following description only only some embodiments of the present application, and for those skilled in the art, other drawings can be obtained based on these drawings without creative labor.
[0023] Figure 1 FT-IR spectra of (a) 3S-CTF, (b) 0S-CTF and corresponding monomers.
[0024] Figure 2 SEM images of (a) 3S-CTF, (b) 0S-CTF 13 CP / MAS ssNMR test spectrum.
[0025] Figure 3 SEM images of (a) 3S-CTF, (b) 0S-CTF
[0026] Figure 4 SEM images and EDX spectra of aluminum sheet as 3S-CTF substrate.
[0027] Figure 5 SEM images and EDX spectra of aluminum sheet as 0S-CTF substrate.
[0028] Figure 6 N2 adsorption isotherms of 3S-CTF and 0S-CTF at 77K.
[0029] Figure 7 FT-IR spectra of 3S-CTF after soaking in different solvents.
[0030] Figure 8 UV-vis DRS spectra of 3S-CTF and 0S-CTF.
[0031] Figure 9 Band gap energy spectra of 3S-CTF and 0S-CTF calculated by Kubelkα-Munk formula.
[0032] Figure 10 Photocurrent response spectra of 3S-CTF and 0S-CTF.
[0033] Figure 11 Nyquist impedance plots of 3S-CTF and 0S-CTF.
[0034] Figure 12 NMR hydrogen spectrum of target product 2a.
[0035] Figure 13NMR carbon spectrum of the target product 2a.
[0036] Figure 14 (a) Reusability evaluation of 3S-CTF in photocatalytic hydroxylation reaction; (b) FT-IR spectra of 3S-CTF before and after being treated with catalytic cycle for five times. DETAILED DESCRIPTION
[0037] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the present application.
[0038] Example 1
[0039] The preparation method of the covalent triazine framework photocatalyst based on triselenophene in the present example is as follows:
[0040] Triselenophene-2,6-dicarboxaldehyde (126 mg, 0.5 mmol), NH4I (73 mg, 1 mmol) and iron acetate hydrate (47 mg, 0.225 mmol) were placed in a 25 mL test tube, and 5 mL of o-dichlorobenzene was added. After ultrasonic dispersion for 5 minutes, the reaction was continuously heated at 40, 80, 120 and 160°C for 24 hours on a heating mantle, and the whole reaction was carried out in an air atmosphere, during which stirring and condensation reflux were kept open. After the reaction was completed, the test tube was taken out and cooled to room temperature, 10 mL of dilute hydrochloric acid (1.5 M) / methanol = 1 / 1 was added, and the mixture was stirred and mixed uniformly, then soaked for half an hour, and then the product was separated by centrifugation, and washed with DMF, MeCN, dilute HCl (1.5 M), water and anhydrous ethanol until the liquid was colorless. Then the solid was wetted with anhydrous ethanol and ground into fine powder, and then extracted with methanol by Soxhlet extraction for 24 hours. Finally, the obtained solid was dried in a vacuum drying oven at 70°C for 24 hours. After being taken out and restored to room temperature, the 3S-CTF material was obtained.
[0041] Comparative Example 1
[0042] The preparation method of the covalent triazine framework photocatalyst in the present comparative example is as follows, which is different from that of Example 1 in that the aldehyde monomer is p-phenylenediamine:
[0043] Terephthalaldehyde (67 mg, 0.5 mmol), NH4I (73 mg, 1 mmol) and iron acetate hydrate (47 mg, 0.225 mmol) were placed together in a 25 mL test tube, and 5 mL of o-dichlorobenzene was added. After ultrasonic dispersion for 5 min, the reaction was heated at 40, 80, 120, 160 °C for 24 h successively on a heating mantle, and the whole reaction was carried out in air atmosphere with stirring and condensation reflux on. After the reaction was completed, the test tube was taken out and cooled to room temperature, and 10 mL of dilute hydrochloric acid (1.5 M) / methanol = 1 / 1 was added. After stirring and mixing uniformly, it was soaked for half an hour, and then the product was separated by centrifugation and washed with DMF, MeCN, dilute HCl (1.5 M), water and anhydrous ethanol until the liquid was colorless. Then the solid was wetted with anhydrous ethanol and ground into fine powder, and then Soxhlet extracted with methanol for 24 h. Finally, the obtained solid was dried in a vacuum oven at 70 °C for 24 h. After being taken out and restored to room temperature, the 0S-CTF material was obtained.
[0044] The structural formula of the structural unit in 3S-CTF and 0S-CTF prepared in Example 1 and Comparative Example 1 is as follows, wherein “—” represents the omitted repeating structural unit:
[0045]
[0046] In the FT-IR spectrum, the stretching vibration peak of the aromatic aldehyde group (Ar-CHO) near 1694 cm -1 in CTFs disappeared or was significantly weakened, and the vibration peak of the triazine group was newly added near 1516 cm -1 and 1354 cm -1 , indicating that the aldehyde group participated in the reaction and was polymerized into a triazine ring, which preliminarily verified the successful synthesis of CTFs Figure 1 a-b).
[0047] In the 13 CCP / MAS NMR spectrum, the peaks near 164.4 and 170.6 ppm belong to the carbon atoms in the triazine ring, further confirming the successful condensation of the triazine group Figure 2 a-b). At the same time, the peaks near 144.4 and 138.9 ppm belong to the carbon atoms connected to the triazine ring.
[0048] Therefore, both 3S-CTF and 0S-CTF were proved to be successfully synthesized.
[0049] The morphology of 3S-CTF and 0S-CTF was observed by FE-SEM Figure 3 . Both 3S-CTF and 0S-CTF have similar stacked nano-particle structures.
[0050] At the same time, EDX also shows that C, N and other elements are evenly distributed on the framework of 3S-CTF and 0S-CTF. Figures 4-5 The presence of the S element in 3S-CTF also indicates that the triterthiophene group was successfully introduced into the framework of 3S-CTF.
[0051] N₂ adsorption was performed at 77 K to evaluate the specific surface areas of 3S-CTF and 0S-CTF. Figure 6 As shown, these two CTFs exhibit typical type I adsorption isotherms, indicating microporous characteristics. The calculated BET surface areas of 3S-CTF and 0S-CTF are 124 and 42 m², respectively. 2 g -1 .
[0052] To investigate the chemical stability of these 3S-CTFs, the original 3S-CTF samples were dispersed in various solvents and soaked at 25°C for 3 days. Afterwards, the samples were filtered, washed, and then vacuum dried. Encouragingly, the FT-IR spectra of all samples showed no significant changes compared to the original samples (e.g., ...). Figure 7 ).
[0053] The photoelectric properties of these CTFs are evaluated using ultraviolet-visible spectroscopy (UV-vis) measurements. For example... Figure 8 As shown, these CTFs exhibit a wide absorption range in the visible light region. The maximum peak of the wide absorption band of 3S-CTF is 498 nm, while that of 0S-CTF is 419 nm. Clearly, 3S-CTF has a superior visible light absorption range compared to 0S-CTF, demonstrating that the introduction of the triterthiophene group into the CTF framework causes a redshift of the maximum absorption wavelength. The optical band gaps of 3S-CTF and 0S-CTF, calculated using Kubelka-Munk transform reflectance spectroscopy, are 1.50 eV and 2.41 eV, respectively. Figure 9 This study demonstrates that the introduction of triterethiophene groups into the CTF framework can effectively improve the band gap of CTFs.
[0054] The charge separation and migration behavior of these two CTFs were investigated using TPC measurements and EIS. Figure 10 As shown, the transient photocurrent of 0S-CTF and 3S-CTF increases sequentially. Compared with 0S-CTF, 3S-CTF containing tris(thiophene) groups exhibits a significant improvement in transient photocurrent response, and also demonstrates a faster photoresponse speed, indicating that the charge separation efficiency of photogenerated charges is improved under visible light irradiation. Therefore, tris(thiophene) groups can effectively improve the photoelectric activity of CTFs.
[0055] Furthermore, the impedance of these two CTFs tends to be greater than that of 0S-CTF. Figure 11), if three thienyl groups are introduced onto the framework of CTFs, the charge transfer resistance of CTFs can be effectively reduced, and the electron mobility is higher, thereby more effectively limiting the electron-hole recombination rate.
[0056] The following application experiments use 3S-CTF and 0S-CTF prepared in Example 1 and Comparative Example 1.
[0057] Example 2
[0058] The preparation method of the covalent triazine framework catalyst based on tri-thiophene is as follows:
[0059] Tri-thiophene-2,6-dicarboxaldehyde (126 mg, 0.5 mmol), NH4I (36.5 mg, 0.5 mmol) and iron acetate hydrate (104.4 mg, 0.5 mmol) were placed in a 25 mL test tube, and 2.5 mL of o-dichlorobenzene was added. After ultrasonic dispersion for 5 minutes, it was continuously heated at 40, 80, 120 and 160°C for 24 hours on a heating mantle, and the whole reaction was carried out in an air atmosphere, during which stirring and condensation reflux were kept open. After the reaction was completed, the test tube was taken out and cooled to room temperature, 10 mL of dilute hydrochloric acid (1.5M) / methanol = 1 / 1 was added, stirred and mixed uniformly, then soaked for half an hour, and then the product was separated by centrifugation, washed with DMF, MeCN, dilute HCl (1.5M), water and anhydrous ethanol until the liquid was colorless, and then the solid was wetted with anhydrous ethanol and ground into fine powder, then Soxhlet extracted with methanol for 24 hours, and finally the obtained solid was dried in a vacuum drying oven at 70°C for 24 hours. Take out and restore to room temperature to obtain 3S-CTF material.
[0060] Example 3
[0061] The preparation method of the covalent triazine framework catalyst based on tri-thiophene is as follows:
[0062] Tris-bithiophene-2,6-dicarboxaldehyde (126 mg, 0.5 mmol), NH4I (109.5 mg, 1.5 mmol) and iron acetate hydrate (10.4 mg, 0.05 mmol) were placed together in a 25 mL test tube, and 25 mL of o-dichlorobenzene was added. After ultrasonic dispersion for 5 minutes, heating was continued at 40, 80, 120, 160 °C for 24 hours each on a heating mantle, and the whole reaction was carried out in an air atmosphere, during which stirring and the opening of the reflux condenser were maintained. After the reaction was completed, the test tube was taken out and cooled to room temperature, 10 mL of dilute hydrochloric acid (1.5 M) / methanol = 1 / 1 was added, stirred and mixed uniformly, then soaked for half an hour, and then the product was separated by centrifugation, washed with DMF, MeCN, dilute HCl (1.5 M), water and anhydrous ethanol until the liquid was colorless, and then the solid was wetted with anhydrous ethanol and ground into a fine powder, then Soxhlet extracted with methanol for 24 hours, and finally the obtained solid was dried in a vacuum oven at 70 °C for 24 hours. Take it out and restore to room temperature to obtain 3S-CTF material.
[0063] Application Example 1
[0064] In a 20 mL reaction tube, 39 mg of 2-phenylimidazo[1,2-a]pyridine, 5 mg of 3S-CTF catalyst, 10.8 mg of elemental iodine, 58 mg of potassium selenocyanate, and 1.0 mL of THF were weighed. A stirring bar was added, and then stirred at 25 °C under air atmosphere for 24 h under white light (λ≥420 nm) irradiation. After the reaction was completed, the catalyst was removed by filtration, the solvent of the filtrate was removed by rotary evaporation, and then bis(imidazo[1,2-a]pyridin-3-yl)selenide 2a 42.4 mg was obtained by column chromatography separation, with a yield of 91%.
[0065]
[0066] NMR data of bis(imidazo[1,2-a]pyridin-3-yl)selenide 2a (as Figure 12 and 13 ): 1 H NMR (400 MHz, CDCl3): δ 8.02-7.99 (m, 4H), 7.61-7.52 (m, 8H), 7.48 (d, J = 9.0 Hz, 2H), 7.10-7.06 (m, 2H), 6.34 (td, J = 6.9, 1.1 Hz, 2H); 13 C NMR (100 MHz, CDCl3): δ 151.5, 147.3, 134.1, 129.7, 128.8, 128.5, 126.3, 126.1, 117.3, 112.6, 103.8.
[0067] Comparative Application Example 1
[0068] In a 20 mL reaction tube, 39 mg of 2-phenylimidazo[1,2-a]pyridine, 5 mg of 0S-CTF catalyst, 10.8 mg of elemental iodine, 58 mg of potassium selenocyanate, 1.0 mL of THF were weighed. A stir bar was added, and then stirred for 24 h under white light (λ≥420 nm) irradiation at 25°C in air atmosphere. After the reaction was completed, the catalyst was removed by filtration, the filtrate solvent was removed by a rotary evaporator, and then bis(imidazo[1,2-a]pyridin-3-yl)selenide 2a 20.0 mg was obtained by column chromatography separation, with a yield of 43%.
[0069] Comparative Application Example 2
[0070] In a 20 mL reaction tube, 39 mg of 2-phenylimidazo[1,2-a]pyridine, 10.8 mg of elemental iodine, 58 mg of potassium selenocyanate, 1.0 mL of THF were weighed. A stir bar was added, and then stirred for 24 h under white light (λ≥420 nm) irradiation at 25°C in air atmosphere. After the reaction was completed, the catalyst was removed by filtration, the filtrate solvent was removed by a rotary evaporator, and then the target product 2a was not obtained by separation.
[0071] Application Example 2
[0072] In a 100 mL reaction tube, 0.6 g of 2-phenylimidazo[1,2-a]pyridine, 75 mg of 3S-CTF catalyst, 162 mg of elemental iodine, 0.87 g of potassium selenocyanate, 15.0 mL of THF were weighed. A stir bar was added, and then stirred for 24 h under white light (λ≥420 nm) irradiation at 25°C in air atmosphere. After the reaction was completed, the catalyst was removed by filtration, the filtrate solvent was removed by a rotary evaporator, and then bis(imidazo[1,2-a]pyridin-3-yl)selenide 2a 0.587 g was obtained by column chromatography separation, with a yield of 84%.
[0073] The 3S-CTF photocatalyst removed by filtration after the reaction was washed with tetrahydrofuran (20 mL*3), dried in a 70°C vacuum drying oven for 24 h, taken out to room temperature, and then put into the reaction again, and this cycle was repeated 5 times. After 5 cycles of photocatalysis, the yield of the product did not change significantly, as shown in a. Figure 14 The recovered 3S-CTF was characterized by FT-IR, and the 3S-CTF still maintained the original structure, as shown in b. Figure 14 These data fully prove the high stability and recyclability of 3S-CTF.
[0074] Bis(imidazo[1,2-a]pyridin-3-yl)selenide was synthesized in the same way as in Application Example 1, and various reaction conditions and reaction results are shown in Table 1.
[0075] Table 1 Synthesis of various bis(imidazo[l,2-a]pyridin-3-yl)selenides under different conditions
[0076]
[0077]
[0078] From the above examples, it can be seen that the preparation method has wide substrate usability, and the yield can reach medium or above. The 3S-CTF photocatalyst used in the preparation method has high catalytic activity, high reaction efficiency, stable catalyst structure, and no obvious change in catalyst activity after multiple uses.
[0079] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.
Claims
1. A covalent triazine frame photocatalyst based on terthiophene, characterized in that, The covalent triazine framework photocatalyst is composed of several repeating structural units, wherein the structural formula of the structural unit is shown in formula I, wherein "--" represents the omitted repeating structural unit.
2. The method of preparing the covalent triazine framework photocatalyst of claim 1, characterized in that, The steps are as follows: uniformly mixing triphenodioxazine-2,6-dicarboxaldehyde, a nitrogen source, a catalyst and a solvent A to prepare a reaction solution A, then performing a condensation reaction, and obtaining a triphenodioxazine-based covalent triazine framework photocatalyst after the reaction is completed.
3. The method for preparing the covalent triazine framework photocatalyst according to claim 2, characterized in that, The molar ratio of the triphenodioxazine-2,6-dicarboxaldehyde, the nitrogen source and the catalyst is 1:(1-3):(0.1-1); and the solvent A is o-dichlorobenzene, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide or 1,4-dioxane.
4. The method for preparing the covalent triazine framework photocatalyst according to claim 3, characterized in that, The nitrogen source is ammonium chloride, ammonium bromide or ammonium iodide.
5. The method for preparing the covalent triazine framework photocatalyst according to claim 4, characterized in that, The catalyst is ferric trichloride, iron acetate or aluminum trichloride.
6. The method of claim 5, wherein the covalent triazine framework photocatalyst is prepared by the reaction of a compound of formula (I) with a compound of formula (II) in the presence of a base. The concentration of the triphenodioxazine-2,6-dicarboxaldehyde in the reaction solution A is 0.02-0.2 mol / L.
7. The method for preparing the covalent triazine framework photocatalyst according to claim 6, characterized in that, The temperature of the condensation reaction is 40-160℃, and the time is 1-4 days.
8. Application of the triphenodioxazine-based covalent triazine framework photocatalyst in catalyzing synthesis of bis(imidazo[1,2-α]pyridin-3-yl) selenide.
9. Use of the covalent triazine framework photocatalyst based on three dithiophenes according to claim 8 for catalyzing the synthesis of bis(imidazo[l,2-α]pyridin-3-yl)selenide, characterized by, The steps of the reaction for synthesizing bis(imidazo[1,2-α]pyridin-3-yl) selenide are as follows: uniformly mixing the triphenodioxazine-based covalent triazine framework photocatalyst, an imidazo[1,2-α]pyridine derivative, elemental iodine, potassium selenocyanate and a solvent B to prepare a reaction solution B, and performing the reaction under visible light irradiation.
10. Use of a covalent triazine framework photocatalyst based on three dithiophenes according to claim 9 for catalyzing the synthesis of bis(imidazo[l,2-α]pyridin-3-yl)selenide, characterized in that, The amount of the triphenodioxazine-based covalent triazine framework photocatalyst added based on the solvent B is 1-100 mg / mL; the concentration of the imidazo[1,2-α]pyridine derivative in the reaction solution B is 0.1-1 mol / L, the concentration of the elemental iodine is 0.02-0.2 mol / L, and the concentration of the potassium selenocyanate is 0.2-2 mol / L; and the solvent B is tetrahydrofuran.