Polymers of the [2+2] photocycloaddition reaction

Abstract

The application relates to the structural composition of a [2+2] photocycloaddition polymer and a preparation method thereof, and relates to the technical field of functional materials. The polymer introduces a closed dodecaborane anion, two polymers are prepared by the application, and the two polymers can both undergo [2+2] cycloaddition under the irradiation of ultraviolet light. The [2+2] cycloaddition of the polymer is verified by nuclear magnetic resonance hydrogen spectrum, single crystal X-ray diffraction spectrum, powder single crystal X-diffraction spectrum, infrared spectrum and the like. The application shows the great potential of a supramolecular organic framework material based on B 12 H 12 2‑ in the field of topological chemistry, and lays a solid foundation for the in-depth research in the field in the future.

Description

Technical Field

[0001] This invention belongs to the field of functional materials technology, and relates to the structural composition and preparation method of a type of polymer with [2+2] photocycloaddition reaction. Background Technology

[0002] With the rapid development of materials science, functionalized materials are increasingly widely used in optoelectronic devices, smart sensing, biomedicine, and other fields. Among them, functional materials based on the [2+2] photocycloaddition reaction have become a research hotspot due to their unique dynamic responsiveness and structural designability. The [2+2] photocycloaddition reaction refers to the process in which two olefin units undergo a cycloaddition reaction under photoexcitation to form a cyclobutane structure. This reaction has the characteristics of mild conditions, high selectivity, and strong reversibility, providing an important pathway for the development of novel photoresponsive materials.

[0003] Traditional photoresponsive materials mainly rely on mechanisms such as photoisomerization, photochromism, or photofragmentation, but these mechanisms often suffer from slow response speed, poor reversibility, and short fatigue life. In contrast, the [2+2] photocycloaddition reaction has significant advantages: First, the reaction can be carried out at room temperature or low temperature, avoiding material degradation caused by high temperature; second, by rationally designing the molecular structure, the reaction wavelength and efficiency can be precisely controlled; in addition, the reversibility of the [2+2] photocycloaddition reaction endows the material with dynamic response characteristics, enabling intelligent regulation of its performance under external stimuli.

[0004] Currently, research on materials based on [2+2] photocycloaddition reactions mainly focuses on the following aspects: (1) developing efficient photosensitive groups to improve the photoresponse performance of materials; (2) constructing multifunctional molecular systems to achieve multiple response characteristics of materials; and (3) exploring novel assembly strategies to prepare materials with specific structures. However, existing technologies still face some challenges, such as insufficient stability of photosensitive groups, lack of universality in molecular design, and unclear material performance regulation mechanisms. Therefore, developing novel [2+2] photocycloaddition reaction systems and constructing high-performance functional materials has significant scientific importance and application prospects.

[0005] This patent aims to provide a new type of functional material based on the [2+2] photocycloaddition reaction. This material has the characteristics of controllable structure, excellent performance and wide application, which can meet the urgent needs of optoelectronic devices, intelligent sensing, biomedicine and other fields for high-performance functional materials. Summary of the Invention

[0006] This invention relates to a [2+2] photocycloaddition polymer, particularly one incorporating B. 12 H 12 2- High-performance functional materials and their preparation methods. This invention utilizes B...12 H 12 2- By combining the molecule with the [2+2] photocycloaddition reaction, a novel material with excellent photoresponsiveness, stability and functional tunability was constructed.

[0007] To achieve the above-mentioned technical objectives, the present invention mainly adopts the following technical solutions:

[0008] Near-dodecoboronic acid cluster (B 12 H 12 2- ) is a closed-cell borohydride with a closed icosahedral structure and two permanent negative charges. B 12 H 12 2- It exhibits a strong binding affinity for hydrophobic, neutral, or positively charged molecules, driven by the liquid-leaching effect, which promotes supramolecular self-assembly and is orthogonal to the hydrophobic effect. In the past few years, B... 12 H 12 2- This invention utilizes B, which has been applied in the design of supramolecular structures. 12 H 12 2- Two supramolecular polymers were constructed by supramolecular interactions between HMP and PBVB molecules. The powders of both polymers can undergo a [2+2] photocycloaddition reaction under ultraviolet light irradiation.

[0009] In a first aspect, according to the technical solution of the present invention, the [2+2] photocycloaddition polymer 1 includes B 12 H 12 2- And the HMP molecule, whose chemical formula is (HMP2)(B 12 H 12 HMP represents 4-(4-hydroxystyryl)-1-methylpyridinium iodide. The polymer 2 includes B... 12 H 12 2- And the PBVB molecule, whose chemical formula is (PBVB)(B 12 H 12 ), PBVB represents 1,4-bis(2-(1-methylpyridinium-4-yl)vinyl)benzene diiodide

[0010] Secondly, a method for preparing the polymer obtained by the above-mentioned [2+2] photocycloaddition reaction is provided.

[0011] The preparation method of polymer 1 includes the following steps:

[0012] B 12 H 12 2-HMP was dissolved in H2O, the precipitate was collected, and placed in a mixed solvent of DMSO:H2O = 1:1 to obtain polymer 1 powder.

[0013] Furthermore, the synthesis method of the HMP is as follows: 1,4-dimethylpyridinium iodide and 4-hydroxybenzaldehyde are heated and reacted under a protective atmosphere and with the aid of a catalyst.

[0014] Furthermore, the protective atmosphere was nitrogen; the catalyst was piperidine; the heating temperature was 70°C; and the reaction time was 12 hours.

[0015] The preparation method of polymer 2 includes the following steps:

[0016] B 12 H 12 2- PBVB was dissolved in H2O, the precipitate was collected and placed in a mixed solvent of DMSO:CH3CN = 1:1 to obtain polymer 2 powder.

[0017] Furthermore, the synthesis method of the PBVB is as follows: 1,4-dimethylpyridinium iodide and terephthalaldehyde are heated and reacted under a protective atmosphere and with the action of a catalyst.

[0018] Furthermore, the protective atmosphere was nitrogen; the catalyst was piperidine; the heating temperature was 70°C; and the reaction time was 12 hours.

[0019] The significant advantages of this invention are:

[0020] 1. First time B 12 H 12 2- By introducing [2+2] photocycloaddition reaction into the polymer, the [2+2] photocycloaddition reaction was realized.

[0021] 2. The preparation method of this polymer is simple, the reaction conditions are mild, and the photoconversion rate is fast.

[0022] 3. The entire regulation process involves no chemical reagents, making it safe and reliable. (B) 12 H 12 2- The introduction of [a specific ingredient] significantly improves the light and thermal stability of the material. Attached Figure Description

[0023] Figure 1 The proton NMR spectrum of HMP

[0024] Figure 2 The proton NMR spectrum of PBVB

[0025] Figure 3 1H NMR spectrum of polymer 1 powder

[0026] Figure 4 Infrared spectrum of polymer 1 powder

[0027] Figure 5 1H NMR spectrum of polymer 2 powder

[0028] Figure 6 Infrared spectrum of polymer 2 powder

[0029] Figure 7 Powder X-ray diffraction contrast pattern of polymer 1

[0030] Figure 8 Powder X-ray diffraction contrast pattern of polymer 2

[0031] Figure 9 (a) is the "ab" face of the crystal cell of polymer 1; (b) is the "bc" face of the crystal cell; (c) is the "ac" face of the crystal cell; (d) is the arrangement of HMP molecules in the crystal.

[0032] Figure 10 (a) is the "ab" face of the unit cell of polymer 2; (b) is the "bc" face of the unit cell of the crystal; (c) is the "ac" face of the unit cell of the crystal; (d) is the arrangement of PBVB molecules in the crystal.

[0033] Figure 11 The 1H NMR spectrum of polymer 1 powder after illumination

[0034] Figure 12 Infrared spectrum of polymer 1 powder after illumination

[0035] Figure 13 The 1H NMR spectrum of polymer 2 powder after illumination

[0036] Figure 14 Infrared spectrum of polymer 2 powder after illumination Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with embodiments. It should be understood that the specific implementations described herein are merely illustrative and not intended to limit the scope of this application. Reagents not specifically described in detail herein are all conventional reagents and are commercially available; methods not specifically described in detail are all conventional experimental methods and can be obtained from the prior art.

[0038] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence, nor do they substantially limit the technical features thereafter. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0039] Example 1 Synthesis of 1,4-Dimethylpyridinium iodide

[0040] In a 100 mL round-bottom flask, 1.44 g (5.46 mmol) of 4-methylpyridine, 2.28 g (16.06 mmol) of iodomethane, and 20 mL of C2H5OH were added. A magnetic stir bar was added, and the flask was placed in an oil bath at 50 °C. The mixture was stirred for 6 hours and then cooled to room temperature. The precipitate was then collected by filtration, washed with ethanol, and dried to give 3.44 g (14.57 mmol, yield 94.3%) of 1,4-dimethylpyridinium iodide. The synthetic route is as follows:

[0041]

[0042] Example 2 Synthesis of 4-(4-hydroxystyryl)-1-methylpyridinium iodide (HMP)

[0043] Weigh 1,4-dimethylpyridinium iodide (600 mg, 2.55 mmol), 4-hydroxybenzaldehyde (360 mg, 2.95 mmol), and piperidine (4.25 mg, 0.05 mmol) into a 100 mL round-bottom flask containing 20 mL of acetonitrile. Seal the flask with a three-way valve connected to a balloon at one end, purge five times under N2 atmosphere, place it in an oil bath at 70 °C, stir for 12 hours, and cool to room temperature. Remove the reaction solvent by rotary evaporation under reduced pressure, dissolve the resulting precipitate in 5 mL of methanol, and then add it dropwise to 50 mL of diethyl ether. A red precipitate forms. Filter to remove the solvent, wash the precipitate with diethyl ether, and dry to obtain pure HMP (793.42 mg, 2.34 mmol, yield 91.8%). Its 1H NMR spectrum is shown below. Figure 1 As shown, the synthesis route is as follows:

[0044]

[0045] Example 3 Preparation of 1,4-bis(2-(1-methylpyridinium-4-yl)vinyl)benzene diiodide (PBVB)

[0046] Weigh 1,4-dimethylpyridinium iodide (1.2 g, 5.1 mmol), terephthalaldehyde (268 mg, 2 mmol), and piperidine (4.25 mg, 0.05 mmol) and add them to a round-bottom flask containing 20 mL of acetonitrile. Seal the flask with a three-way valve connected to a balloon at one end, purge five times under N2 atmosphere, place it in an oil bath at 70 °C, stir for 12 hours, and cool to room temperature. Remove the reaction solvent by rotary evaporation under reduced pressure, and dissolve the precipitate in 5 mL of methanol. Then add it dropwise to 50 mL of diethyl ether, and a yellow precipitate forms. Filter to remove the solvent, wash the precipitate with diethyl ether, and dry to obtain pure PBVB (1.01 g, 1.78 mmol, yield 89%). Its 1H NMR spectrum is shown below. Figure 2 As shown, the synthesis route is as follows:

[0047]

[0048] Example 4 Polymer (HMP2)(B 12 H 12 Synthesis of (1)

[0049] Add 1 mL of 5 mM DMSO solution to the NMR tube using a long needle. Then, add 0.1 mL each of DMSO and H2O along the tube wall. Finally, slowly add Cs2B dropwise along the tube wall. 12 H 12 1 mL of a 5 mM aqueous solution was prepared. The NMR tube was tightly sealed with an NMR tube cap and then placed in a completely dark environment for one week to obtain crystal 1.

[0050] Powder synthesis in Example 5(1)

[0051] Weigh out HMP powder (68 mg, 0.2 mmol), Cs2B 12 H 12 The powder (50.0 mg, 0.12 mmol) was mixed and dissolved in 20 mL of deionized water. After sonication for 30 min, a yellow precipitate formed in the solution. The solvent was removed by filtration, and the precipitate was collected after washing with a small amount of deionized water and then dried under vacuum. The precipitate was dissolved in a 1:1 mixture of DMSO and H2O, sonicated for 6 h, and then evaporated under reduced pressure to obtain 44.2 mg of yellow powder, with a yield of 77.8%, which is the powder of complex (1). Its 1H NMR spectrum is as follows: Figure 3 As shown, the infrared spectrum is as follows Figure 4 As shown.

[0052] Example 6 Polymer (PBVB)(B) 12 H12 Synthesis of (2)

[0053] Cs2B was added into the MRI tube using a long needle. 12 H 12 1 mL of 5 mM DMSO solution was added, followed by 0.1 mL each of DMSO and CH3CN along the wall of the NMR tube. Finally, 1 mL of 5 mM CH3CN OPVE solution was slowly added dropwise along the wall of the NMR tube. The NMR tube was then sealed tightly with an NMR tube cap and placed in a completely dark environment for 3 days to obtain a single crystal.

[0054] Powder synthesis in Example 7(2)

[0055] Weigh out PBVB powder (57 mg, 0.1 mmol), Cs2B 12 H 12 The powder (50.0 mg, 0.12 mmol) was mixed and dissolved in 20 mL of deionized water. After sonication for 30 min, a yellow precipitate formed in the solution. The solvent was removed by filtration, and the precipitate was collected after washing with a small amount of deionized water and then dried under vacuum. The precipitate was dissolved in a 1:1 mixture of DMSO and CH3CN, sonicated for 6 h, and then rotary evaporated under reduced pressure to obtain 38.6 mg of a bright yellow powder, with a yield of 84.3%, which is the powder of complex B (2). Its 1H NMR spectrum is as follows: Figure 5 As shown, the infrared spectrum is as follows Figure 6 As shown.

[0056] Experimental Section

[0057] 1. Materials

[0058] B 12 H 12 2- The synthesis was reported in J. Mater. Chem. A. 5(26)(2017) 13341-13346. Other chemicals and reagents were purchased directly from the procurement platform.

[0059] 2. Instruments

[0060] 1H NMR spectra were determined using DMSO-d6 solvent at room temperature on an Agilent Technologies 600MHz NMR spectrometer, and chemical shifts were determined based on the DMSO-d6 solvent peaks. The chemical composition of the samples was analyzed using a Tensor II Fourier Transform Infrared (FTIR) spectrometer (FLIR A35 FOV 25 (60Hz)). X-ray powder diffraction (PXRD) data were obtained on a Bruker D8 Advance powder diffractometer at a plotting speed of 4°min. -1 The scanning range is 2θ = 3° to 60°.

[0061] Results and Analysis

[0062] 1. Synthesis of coordination compounds

[0063] The powder X-ray diffraction patterns of the powders obtained in Examples 5 and 7 are basically consistent with the simulated X-ray diffraction patterns of the crystals, such as... Figure 7 , Figure 8 As shown, this demonstrates that the powder has a good crystal structure and can exhibit the crystal structure of the corresponding crystal.

[0064] 2. Crystal determination and crystal structure

[0065] Single-crystal X-ray diffraction tests were performed on compounds 1 and 2 obtained in Examples 4 and 6: Crystal data for compounds 1 and 2 were collected using an Agilent Super-Nova diffractometer. The structures were solved and refined using the SHELX software package (Bruker). Empirical absorption correction was performed using the SADABS program. The direct method was used for solving, and the anisotropic thermal parameters of all heavy atoms in the model were refined using the full matrix least squares method (Σw(|Fo|2-|Fc|2)2). The positions of hydrogen atoms in organic groups were introduced into the geometric calculations. The main crystal data and correction parameters of complexes 1 and 2 are shown in Table 1. The partial double hydrogen bond (HC···HB) bond lengths were analyzed using MaterialsStudio. The bond angles (deg) are shown in Table 2.

[0066] Table 1 Crystal data of compounds 1 and 2

[0067]

[0068]

[0069] Table 2 shows the partial double hydrogen bond lengths in the crystals of compounds 1 and 2. With bond angle (deg) parameter.

[0070]

[0071] B in crystal 1 12 H 12 2- The arrangement of HMP molecules is as follows Figure 9 As shown in (a), (b), and (c), the double bonds of two adjacent HMP molecules are arranged in parallel. Figure 9 (d)). B in crystal 2 12 H 12 2- The arrangement of PBVB molecules is as follows Figure 10As shown in (a), (b), and (c), PBVB molecules are arranged in an out-of-phase configuration. Figure 10 (d)) The double bonds of adjacent olefins are arranged in parallel.

[0072] 3. Cycloaddition reaction

[0073] 20 mg of the crystal powder prepared in Examples 5 and 7 were weighed out respectively, ground into fine powder, and clamped between two glass slides. The slides were then irradiated under a 395 nm ultraviolet lamp for 6 hours. The crystal powder in the glass slides was mixed every 30 minutes to ensure uniform irradiation. The proton NMR spectrum is shown below. Figure 11 , Figure 13 As shown, the infrared spectrum is as follows Figure 12 , Figure 14 As shown.

[0074] In summary, this invention combines B 12 H 12 2- Two polymers were obtained from HMP and PBVB molecules, which underwent a [2+2] photocycloaddition reaction under ultraviolet light irradiation. In summary, this invention demonstrates a B-based... 12 H 12 2- The enormous potential of supramolecular organic framework materials in the field of topology has laid a solid foundation for future in-depth research in this field.

[0075] The above description is merely a preferred embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application.

Claims

1. A type of [2+2] halo addition material, characterized in that: The resulting polymer undergoes a [2+2] photocycloaddition reaction under ultraviolet light. Polymer 1 includes B. 12 H 12 2- The HMP molecule has the chemical formula (HMP2)(B 12 H 12 Polymer 2 includes B 12 H 12 2- The PBVB molecule has the chemical formula (PBVB)(B 12 H 12 ).

2. The [2+2] halo addition material according to claim 1, characterized in that: The closed dodecorane anion is used to construct polymers by supramolecular interactions between the closed dodecorane anion and HMP and PBVB molecules.

3. The [2+2] halo addition material according to claim 2, characterized in that: The polymer 1 is prepared by the following method: B 12 H 12 2- HMP was dissolved in H2O, the precipitate was collected, and placed in a mixed solvent of DMSO:H2O = 1:1 to obtain polymer 1 powder.

4. The [2+2] halo addition material according to claim 2, characterized in that: The polymer 2 is prepared by the following method: B 12 H 12 2- PBVB was dissolved in H2O, the precipitate was collected and placed in a mixed solvent of DMSO:CH3CN = 1:1 to obtain polymer 2 powder.

5. The [2+2] halo addition material according to claim 2, characterized in that: The reaction was induced by ultraviolet light to undergo a [2+2] cycloaddition reaction.

6. The [2+2] halo addition material according to claim 2, characterized in that: The method for preparing polymer 1 crystals is as follows: Cs2B is added into the NMR tube using a long needle. 12 H 12 1 mL of 5 mM DMSO solution was added, followed by 0.1 mL each of DMSO and H2O along the wall of the NMR tube. Finally, 1 mL of 5 mM H2O solution was slowly added dropwise along the wall of the NMR tube. The NMR tube was then tightly sealed with an NMR tube cap and placed in a completely dark environment for 3 days to obtain a single crystal.

7. The [2+2] halo addition material according to claim 2, characterized in that: The method for preparing polymer 2 crystals is as follows: Cs2B is added into the NMR tube using a long needle. 12 H 12 1 mL of 5 mM DMSO solution was added, followed by 0.1 mL each of DMSO and CH3CN along the wall of the NMR tube. Finally, 1 mL of 5 mM CH3CN PBVB solution was slowly added dropwise along the wall of the NMR tube. The NMR tube was then tightly sealed with an NMR tube cap and placed in a completely dark environment for 3 days to obtain a single crystal.

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