A Keggin-type phosphomolybdic acid derivative, its preparation method and application
By preparing Keggin-type phosphomolybdic acid derivatives in an aqueous system, the complexity of synthesis and environmental issues in organic modification chemistry of polyacids have been solved, and high-yield and high-stability polyacid derivatives with excellent photocatalytic performance have been achieved.
Patent Information
- Application Number
- CN202310276922.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-03-17
- Publication Date
- 2025-12-02
- Estimated Expiration
- 2043-03-17
AI Technical Summary
Existing organic modification chemistry for polyacids involves complex synthesis steps, long processes, low yields, and unfriendly reaction environments. It also requires the use of organic solvents and harsh conditions, which limits its development and application.
Keggin-type phosphomolybdic heteropolyacid derivatives were prepared in an aqueous system by hydrothermal reaction. Pyridine was used as an organic base to react with the Keggin-type phosphomolybdic heteropolyacid to form green crystals. The Keggin-type phosphomolybdic heteropolyacid derivatives were obtained in high yield by chiral resolution.
A green and environmentally friendly synthesis process was achieved, simplifying the steps, increasing the yield, and providing highly stable and high-purity heteropolyacid derivatives with excellent photocatalytic degradation performance.
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Figure CN117229326B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of medicinal chemistry technology and relates to a heteropolyacid derivative, specifically a Keggin-type phosphomolybdic acid derivative and its preparation method and application. Background Technology
[0002] Polyacid organic modification chemistry refers to the process of replacing oxygen atoms on the surface of polyacids with organic molecules, thereby combining polyacids and organic molecules through covalent modification to form polyacid organic derivatives. Polyacid derivatives, after organic covalent modification, often exhibit excellent catalytic activity and high antitumor and antiviral pharmacological activities, making it a hot topic in polyacid chemistry in recent decades. Although various surface modification methods such as organic iminolation, organic alkane oxidation, organosilylation, and organophosphorylation have been developed, their preparation methods still have some shortcomings: (1) The synthesis steps are complex, the process is long, and the yield is low; (2) The synthesis environment is mostly an organic solvent reaction system, such as DMF / DMA, acetonitrile, ethanol, diethyl ether, acetone, etc., which are highly volatile and toxic, and do not conform to the concept of green chemistry; (3) The reaction conditions are harsh. Taking the typical polyacid iminolation as an example, the Mo≡N triple bond formed by covalent modification can only be formed under a strict anhydrous, organic solvent, or even inert gas protective atmosphere. These technical bottlenecks greatly limit the development and application of this system in various fields. Exploring and developing new green, economical, and efficient organic synthesis reactions is an effective way to solve the current technical problems of reaction systems. Summary of the Invention
[0003] One of the objectives of this invention is to provide a method for preparing Keggin-type phosphomolybdic heteropolyacid derivatives, which can react in an aqueous system, is environmentally friendly, has simple steps, and can effectively solve many technical problems in the traditional organication of polyacids.
[0004] A second objective of this invention is to provide a Keggin-type phosphomolybdic heteropolyacid derivative prepared by the above-described method, with a high yield.
[0005] A third objective of this invention is to provide the use of the above-mentioned Keggin-type phosphomolybdic heteropolyacid derivatives.
[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:
[0007] In a first aspect, the present invention provides a method for preparing a Keggin-type phosphomolybdic heteropolyacid derivative, using Keggin-type phosphomolybdic heteropolyacid (H3PMo) 12 O 40 Using 13H2O and organic base pyridine molecules (C5H5N,py) as raw materials, a green crystal was obtained through a hydrothermal reaction. After chiral resolution, the Keggin-type phosphomolybdic heteropolyacid derivative Λ-[PMo9O] was obtained.31 (py)3]·(Hpy)3·(py)3 and Δ-[PMo9O 31 (py)3]·(Hpy)3·(py)3.
[0008] Preferably, the specific steps of the hydrothermal reaction are as follows:
[0009] S1. At room temperature, pyridine (C5H5N,py) is slowly added dropwise to Keggin-type phosphomolybdic acid (H3PMo). 12 O 40 After adding the 13H2O to an aqueous solution, stir to disperse.
[0010] S2. Transfer the mixture after step S1 to a polytetrafluoroethylene reactor and keep it at 140℃-160℃ for 2 to 3 days.
[0011] S3. After the reaction is complete, allow it to cool naturally to room temperature, filter, and obtain green crystals, which are the organic derivative compound [PMo9O]. 31 (py)3]·(Hpy)3·(py)3;
[0012] S4. The crystals obtained in step S3 are collected by chiral separation under a polarizing microscope to obtain Λ-[PMo9O] 31 (py)3]·(Hpy)3·(py)3 and Δ-[PMo9O 31 (py)3]·(Hpy)3·(py)3 is a pair of enantiomers in crystal.
[0013] Preferably, the ratio of pyridine, Keggin-type phosphomolybdic heteropolyacid, and water is (1-2 mL): (0.20-0.25 g): (3-4 mL).
[0014] Preferably, the stirring time in step S1 is 15 to 30 minutes.
[0015] Secondly, the present invention also provides a Keggin-type phosphomolybdic heteropolyacid derivative prepared by the above preparation method.
[0016] Preferably, the Keggin-type phosphomolybdic heteropolyacid derivative consists of a pair of enantiomers that are mirror images of each other in structure, and are denoted as Λ-[PMo9O] according to their chirality. 31 (py)3]·(Hpy)3·(py)3 and Δ-[PMo9O 31 [(py)3]·(Hpy)3·(py)3, both crystals belong to the trigonal crystal system, and their space group is R3 (No. 146); the Λ-[PMo9O 31 The unit cell parameters of [(py)3]·(Hpy)3·(py)3 are: β = 120°; Flack parameters: -0.009(7), T=296(2)K; the Δ-[PMo9O 31 The unit cell parameters of [(py)3]·(Hpy)3·(py)3 are: β = 120°; Flack parameters: 0.19(5), T=296(2)K; The smallest asymmetric structural unit in the crystal structure of the organic derivative compound contains 1 / 3 of a triple-vacancy Keggin type [PMo9O] with C3 symmetry. 31 (py)3] 3- The anion consists of a protonated pyridine cation (Hpy) and a neutral pyridine molecule, wherein the [PMo9O] molecule is triple-vacant. 34 ] 9- The three Mo(VI) atoms in the middle coordinate with the three nitrogen atoms of the three pyridine (py) molecules to form a triple-vacant Keggin-type [PMo9O] 31 (py)3] 3- Anions.
[0017] Thirdly, the present invention also provides the application of the above-mentioned Keggin-type phosphomolybdic heteropolyacid derivative in the photocatalytic degradation of methylene blue dye.
[0018] Compared with the prior art, the present invention has the following beneficial effects:
[0019] 1. The preparation method of the Keggin-type phosphomolybdic acid derivative of the present invention is simple, the reaction conditions are mild and controllable, it is environmentally friendly, does not use organic solvents, does not require the pre-preparation of precursors, and saturates [PMo] under hydrothermal conditions. 12 O 40 ] 3- Ions degrade in situ into triple-vacant [PMo9O] 34 ] 9- Ions, and py molecules can replace some oxygen atoms on the surface of polyacid anions to generate [PMo9O]. 31 [(py)3]·(Hpy)3·(py)3, thus achieving organic covalent modification of polyacids, with low cost and good reproducibility, bringing new opportunities and broad development prospects to the organic modification chemistry of polyacids;
[0020] 2. This invention is the first to obtain Keggin-type phosphomolybdic heteropolyacid derivatives, which have good stability, high yield and high purity, providing a new direction for the exploration of their structure.
[0021] 3. The Keggin-type phosphomolybdic acid derivative of the present invention can be used for photocatalytic degradation of methylene blue, and has extremely high potential application value in the field of catalysis. Attached Figure Description
[0022] Figure 1 It is a derivative Λ-[PMo9O] 31 Coordination mode of [(py)3]·(Hpy)3·(py)3;
[0023] Figure 2 It is a derivative Δ-[PMo9O] 31 Coordination mode of [(py)3]·(Hpy)3·(py)3;
[0024] Figure 3 It is a derivative [PMo9O] 31 X-ray powder diffraction pattern of [(py)3]·(Hpy)3·(py)3;
[0025] Figure 4 It is a derivative Λ-[PMo9O] 31 (py)3]·(Hpy)3·(py)3 and Δ-[PMo9O 31 CD spectrum of [(py)3]·(Hpy)3·(py)3;
[0026] Figure 5 It is a derivative [PMo9O] 31 XPS spectra of [(py)3]·(Hpy)3·(py)3;
[0027] Figure 6 It is a derivative [PMo9O] 31 3d XPS spectrum of Mo in [(py)3]·(Hpy)3·(py)3;
[0028] Figure 7 It is a derivative [PMo9O] 31 Thermogravimetric analysis (TGA) curves of (py)3]·(Hpy)3·(py)3;
[0029] Figure 8 It is a derivative [PMo9O] 31 Photodegradation diagram of methylene blue by (py)3]·(Hpy)3·(py)3. Detailed Implementation
[0030] The present invention will be further described in detail below with reference to specific embodiments, but the invention is not limited thereto. Furthermore, the embodiments only provide some conditions for achieving this objective, but do not imply that these conditions must be met to achieve this objective.
[0031] Example 1: Derivative [PMo9O] 31 Synthesis of (py)3]·(Hpy)3·(py)3
[0032] 2 mL of pyridine (C5H5N, py) was slowly added dropwise to the Keggin-type heteropolyacid (H3PMo). 12 O 40 The mixture was stirred and dispersed in an aqueous solution of ·13H2O for 30 minutes, then transferred to a polytetrafluoroethylene reactor and reacted at 160°C for 3 days. After the reaction was completed, the mixture was allowed to cool naturally to room temperature and filtered to obtain green crystals with a yield of 72% (based on Mo). The obtained crystals were then chirally separated under a polarizing microscope to obtain Λ-[PMo9O] 31 (py)3]·(Hpy)3·(py)3 and Δ-[PMo9O 31 [(py)3]·(Hpy)3·(py)3 is a pair of enantiomeric crystal materials.
[0033] Example 2: [PMo9O] 31 Structural characterization of [(py)3]·(Hpy)3·(py)3 derivatives
[0034] Structural determination of the derivatives: Two single crystals of suitable size were selected and subjected to X-ray single-crystal diffraction experiments at room temperature under a microscope. X-ray single-crystal diffraction data were obtained using a Bruker Smart Apex II CCD diffractometer, with graphite-monochromatic Mo Kα (λ = 0.071073 nm) radiation as the light source. The collected data were corrected for absorption using SADABS, and the crystal structure was solved directly using the SHELXTL program. The coordinates of non-hydrogen atoms were determined successively in subsequent rounds of difference Fourier synthesis, based on F... 2 The coordinates and anisotropy parameters of all non-hydrogen atoms were refined using the least squares method. All hydrogen atoms on carbon atoms were obtained by theoretical hydrogenation. Crystallographic data of the derivatives are shown in the table.
[0035] Table 1 Crystallographic data of derivatives
[0036]
[0037]
[0038] a R1=Σ||F0|–|F c || / Σ|F0|, b wR2=Σ[w(F0 2 –F c 2 ) 2 ] / Σ[w(F0 2 )2 ] 1 / 2 w = 1 / [σ 2 (F o 2 )+(aP) 2 +bP],P=(F o 2 +2F c 2 ) / 3
[0039] Λ-[PMo9O 31 (py)3]·(Hpy)3·(py)3 and Δ-[PMo9O 31 The crystal structures of [(py)3]·(Hpy)3·(py)3 are as follows: Figure 1 and Figure 2 As shown, the smallest asymmetric structural unit in the crystal structure contains 1 / 3 of a triple-vacancy Keggin-type [PMo9O] with C3 symmetry. 31 (py)3] 3- The anion consists of a protonated pyridine cation (Hpy) and a neutral pyridine molecule. The [PMo9O] molecule is tri-vacant. 34 ] 9- The three Mo(VI) atoms in the middle coordinate with the three nitrogen atoms of the three pyridine (py) molecules to form a triple-vacant Keggin-type [PMo9O] 31 (py)3] 3- Anions.
[0040] Powder diffraction determination of derivatives: A suitable amount of the derivatives of this invention were selected and powder diffraction was performed at room temperature using a Bruker D8 X-ray diffractometer. The test results are as follows: Figure 3 As shown, the experimentally measured spectrum and the simulated spectrum are in good agreement, indicating that the synthesized derivative is a pure phase.
[0041] CD spectral characterization of derivatives: Figure 4 It is Λ-[PMo9O 31 (py)3]·(Hpy)3·(py)3 and Δ-[PMo9O 31 The CD spectrum of [(py)3]·(Hpy)3·(py)3 indicates that Λ-[PMo9O] 31 The CD spectrum of [(py)3]·(Hpy)3·(py)3 exhibits a significant positive cotton effect, maximizing at approximately 250, 375, 400, and 475 nm, with several weak positive cotton effects in the 300-375 nm range, and a weak negative cotton effect at 450 nm. These results indicate that Λ-[PMo9O] 31[(py)3]·(Hpy)3·(py)3 is a crystal with single chirality, consistent with the value of the single-crystal Flack parameter. Δ-[PMo9O 31 The CD spectrum of [(py)3]·(Hpy)3·(py)3 did not show a significant negative Cotton effect in the 200-300 nm range, but several weak interactions with Λ-[PMo9O] were observed in the 300-450 nm range. 31 [(py)3]·(Hpy)3·(py)3 exhibits a mirror-symmetric Cotton effect, which is due to Δ-[PMo9O 31 [(py)3]·(Hpy)3·(py)3 crystals are twinned, consisting of two components of single chirality in unequal amounts (twin composition is 0.19(5)), indicating that Δ-[PMo9O 31 The single-crystal structure of (py)3]·(Hpy)3·(py)3 exhibits a moderate enantiomeric excess, consistent with the values of the single-crystal Flack parameter.
[0042] XPS spectral characterization of the derivatives: Figure 5 The XPS spectrum of the prepared derivative shows that it contains C, N, O, P, and Mo elements; valence calculations show that all Mo atoms in the derivative have a +6 valence. Figure 6 The image shows the 3d XPS spectrum of Mo in the prepared derivative. The peaks at 232.8 eV and 235.9 eV are attributed to Mo. 6+ 3D 5 / 2 and 3D 3 / 2 The characteristic peaks were consistent with the single-crystal diffraction results.
[0043] Thermogravimetric analysis of derivatives: Figure 7 The thermogravimetric analysis (TGA) curves of the prepared derivatives show that there was no weight loss in the range of room temperature to 158 °C, indicating that the complex is stable up to 158 °C. In the range of 158–485 °C, the weight loss rate was 32.3%, consistent with the weight loss rates of coordinated pyridine and free pyridine (calculated value 32.9%). In the range of 485–600 °C, corresponding to the decomposition of [PMo9], the final residue after decomposition was MoO3 (experimental value 62.0%, calculated value 61.5%). The analytical results indicate that the prepared derivatives possess good thermal stability.
[0044] Example 2: Photocatalytic Experiment of Derivatives
[0045] The derivative [PMo9O] prepared using Example 1 31Photocatalytic experiments were conducted using [(py)3]·(Hpy)3·(py)3. The specific implementation method was as follows: 80.0 mg of the derivative was added to 50.0 mL of a methylene blue dye aqueous solution (6.0 mg / L). The mixture was stirred in the dark to ensure thorough mixing of the derivative and the methylene blue dye solution, reaching adsorption / desorption equilibrium. The mixture was then irradiated at room temperature with a 300W xenon lamp for a certain period (0-90 min) under stirring. Every 30 minutes, 3.0 mL of the reaction solution was drawn using a syringe, and the relative concentration of methylene blue was measured and analyzed using a UV-Vis spectrophotometer. The results are shown in […]. Figure 8 After irradiation for 90 minutes, the derivative prepared in Example 1 of this invention could degrade nearly 77% of methylene blue. Experimental results indicate that the derivative prepared in Example 1 of this invention possesses good photocatalytic activity.
[0046] The embodiments of the present invention have been described above. However, the present invention is not limited to the above embodiments. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A method for preparing a Keggin-type phosphomolybdic heteropolyacid derivative, characterized in that, Keggin-type phosphomolybdic acid H3PMo 12 O 40 Using 13H2O and organic base pyridine molecules as raw materials, a hydrothermal reaction yielded green crystals. After chiral resolution, Keggin-type phosphomolybdic acid derivatives were obtained. Λ -[PMo9O 31 [(py)3]·(Hpy)3·(py)3 and -[PMo9O 31 (py)3]·(Hpy)3·(py)3; The specific steps of the hydrothermal reaction are as follows: S1. Pyridine is slowly added dropwise to an aqueous solution of Keggin-type phosphomolybdic heteropolyacid at room temperature, and the mixture is stirred and dispersed after the addition is complete; the ratio of pyridine, Keggin-type phosphomolybdic heteropolyacid and water is (1-2 mL): (0.20-0.25 g): (3-4 mL); S2. Transfer the mixture after step S1 to a polytetrafluoroethylene reactor and keep it at 140℃~160℃ for 2~3 days. S3. After the reaction is complete, allow it to cool naturally to room temperature, filter, and obtain green crystals, i.e., the derivative [PMo9O]. 31 (py)3]·(Hpy)3·(py)3; S4. The crystals obtained in step S3 are collected by chiral separation under a polarizing microscope to obtain... Λ -[PMo9O 31 [(py)3]·(Hpy)3·(py)3 and -[PMo9O 31 (py)3]·(Hpy)3·(py)3 is a pair of enantiomers in crystal.
2. The method for preparing a Keggin-type phosphomolybdic heteropolyacid derivative according to claim 1, characterized in that, The stirring time in step S1 is 15 to 30 minutes.
3. A Keggin-type phosphomolybdic heteropolyacid derivative prepared by the preparation method described in claim 1 or 2.
4. The derivative [PMo9O] prepared by the preparation method according to claim 1 or 2 31 Application of (py)3]·(Hpy)3·(py)3 in the photocatalytic degradation of methylene blue dye.