An azobenzene-based heterochain fluorescent polymer, a preparation method and application thereof

Abstract

The application discloses an azobenzene-based heterochain fluorescent polymer and a preparation method and application thereof, and relates to the technical field of heterochain polymer luminescence. The method uses azobenzene epoxide alkane as raw material, and obtains the azobenzene-based heterochain fluorescent polymer through bulk polymerization, melt polymerization or solution polymerization under the action of a catalyst; the azobenzene-based heterochain fluorescent polymer obtained by the method has good solubility in various organic solvents, and the luminescence property of the polymer can be changed by adjusting the concentration and inducing photoisomerization of the azobenzene group, so that the azobenzene-based heterochain fluorescent polymer has good application potential.

Description

Technical Field

[0001] This invention relates to the field of heterochain polymer luminescence technology, specifically to an azophenyl heterochain fluorescent polymer, its preparation method, and its applications. Background Technology

[0002] Tunable fluorescent heterochain polymers are polymeric materials prepared through the ring-opening polymerization of epoxide alkanes containing azobenzene. Because the azophenyl group can undergo cis-trans isomerization under the induction of light at specific wavelengths, thereby controlling the physicochemical properties of the polymer, they have become a research hotspot in chemistry, materials science, and other scientific fields. However, the azophenyl group itself does not possess fluorescent properties. Furthermore, heterochain polymers (such as polyesters and polyethers) have attracted widespread research interest and have been widely applied in recent years due to their excellent biocompatibility and fluorescent functions.

[0003] Existing technology discloses a fluorescent polymer in which specific modifying groups are added to a conventional polyester to alter the spatial interactions between the groups within the polymer, thereby changing the polymer's luminescent properties. However, this polymer cannot change its luminescent properties under external stimuli, and the emission wavelength is still insufficient to support its potential biological applications.

[0004] Existing technology also discloses a method for preparing azophenyl polyesters by first ring-opening polymerization between epoxide alkanes with different substituent azophenyl groups and cyclic anhydrides, and then inducing cis-trans isomerization of azobenzene by 365 nm ultraviolet light and 450 nm visible light, respectively. Due to the trans-cis photoisomerization of azobenzene, some polyesters exhibit excellent photoinduced reversible solid-liquid phase transition properties. Trans azopolyesters have a melting temperature of (… T m or glass transition temperature ( T g A yellow solid above room temperature, while cis-polymers are... T g Liquids below -20 °C. This polymer can change its physicochemical properties under external stimuli, but its luminescent properties have not yet been studied. Summary of the Invention

[0005] To address the shortcomings of the aforementioned background technology, this invention provides an azophenyl heterochain fluorescent polymer, its preparation method, and its applications. This azophenyl heterochain fluorescent polymer exhibits good solubility in various organic solvents, and its luminescent properties can be altered by adjusting the concentration and inducing photoisomerization of the azophenyl groups, demonstrating promising application potential. The route provided by this invention offers advantages such as inexpensive catalysts, mild reaction conditions, diverse polymer structures and properties, high molecular weight, controllable and simple polymerization reaction, excellent polymer fluorescence properties, and the ability to achieve stimulus-response.

[0006] The first objective of this invention is to provide an azophenyl heterochain fluorescent polymer, the general structural formula of which is as follows:

[0007] In the formula, X is O, S, N or C; R is selected from H, CH3, CH2CH3, (CH2)2CH3, CH(CH3)2, (CH2)3CH3, C(CH3)3, (CH2)4CH3, (CH2)5CH3, (CH2)6CH3, (CH2)7CH3, OCH3, OCH2CH3, N(Me)2, NO2 or CN; When X is N, R1 is selected from one of the following:

[0008] R2 is selected from H, CH3, CH2CH3, CH(CH3)2, C(CH3)3, OCH3, OCH2CH3, F, Cl, Br, I or NO2.

[0009] Preferably, the azophenyl heterochain fluorescent polymer has a number-average molecular weight of 5000~30000 g / mol and a molecular weight distribution of 1.01~1.7.

[0010] Preferably, the azophenyl heterochain fluorescent polymer undergoes repeated cis-trans isomerization under irradiation with ultraviolet light at wavelengths of 365-385 nm and visible light at wavelengths of 410-450 nm, and its cis-trans isomerization route is as follows: .

[0011] The second objective of this invention is to provide a method for preparing an azophenyl heterochain fluorescent polymer, comprising the following steps: Using azobenzene epoxyalkane and cyclic acid anhydride as raw materials, azobenzene heterochain fluorescent polymers are obtained through bulk polymerization, melt polymerization or solution polymerization under the action of a catalyst. The azobenzene epoxy alkane is selected from one or more of the following:

[0012] Where n = 0~7.

[0013] Preferably, the azophenyl heterochain fluorescent polymer is synthesized by alternating copolymerization of azophenyl epoxides and cyclic anhydrides, and the synthetic route is as follows: ; The cyclic anhydride is selected from one or more of the following: .

[0014] Preferably, the catalyst includes an organic catalyst and a metal-organic catalyst; The organic catalyst is one or more of the following:

[0015] Wherein, A is one of Cl, Br, NO3, and OAc; The organometallic catalyst is:

[0016] In the formula, M represents Al. 3+ Fe 3+ Co 3+ Ni 3+ Cr 3+ Mn 3+ Or Ru 3+ ; B is F - Cl - ,Br - I - NO3 - CH3COO - CCl3COO - CF3COO - ClO4 - BF4 - BPh4 - N3 - p-Toluenesulfonate, p-Nitrophenoloxy, p-Nitrophenoloxy, m-Nitrophenoloxy, 2,4-Dinitrophenoloxy, 3,5-Dinitrophenoloxy, 2,4,6-Trinitrophenoloxy, 3,5-Dichlorophenoloxy, 3,5-Difluorophenoloxy, 3,5-Di-trifluoromethylphenoloxy, or pentafluorophenoloxy anions; R 3 for ; R 4 The possible values ​​are H, CH3, CH2CH3, CH(CH3)2, C(CH3)3, OCH3, OCH2CH3, F, Cl, Br, I, or NO2; R 5 The possible values ​​are H, CH3, CH2CH3, CH(CH3)2, C(CH3)3, OCH3, OCH2CH3, F, Cl, Br, I, or NO2.

[0017] Preferably, the solvent used for solution polymerization is selected from any one of toluene, dioxane, acetonitrile, tetrahydrofuran, and N,N-dimethylformamide.

[0018] Preferably, the molar ratio of the azobenzene epoxy alkane to the cyclic acid anhydride is 1:10 to 10:1; and the molar ratio of the azobenzene epoxy alkane to the catalyst is 10:1 to 10000:1.

[0019] Preferably, the reaction temperature for bulk polymerization, melt polymerization, or solution polymerization is -20 to 200 °C, and the reaction time is 0.1 to 96 h.

[0020] The third objective of this invention is to provide an application of an azophenyl heterochain fluorescent polymer in medicine, bioimaging, ion detection, photolithography, or smart materials.

[0021] Compared with the prior art, the beneficial effects of the present invention are: This invention provides an azophenyl heterochain fluorescent polymer, its preparation method, and its applications. In this invention, the azophenyl group contains various substituents, exhibiting strong structural designability, a wide range of raw material sources, and a large adjustable range of physicochemical properties. It is obtained by polymerizing azophenyl epoxyalkane compounds with monomers such as cyclic anhydrides and isocyanates. The monomers involved are widely available, offering strong designability, thus resulting in polymers with diverse structures and properties.

[0022] Compared to existing polyester preparation technologies, this invention employs active controllable anionic coordination polymerization, which features mild reaction conditions, high catalyst activity, precise polymer structure, high molecular weight, and controllable molecular weight distribution. The resulting fluorescent heterochain polymer can change its emission wavelength, brightness, and glass transition temperature under specific wavelengths of ultraviolet / visible light stimulation, and also exhibits good cycleability. Attached Figure Description

[0023] Figure 1 The fluorescent heterochain polymer product prepared in Example 1 is trans- 1 H NMR spectrum; Figure 2 The fluorescent heterochain polymer product prepared in Example 1 is trans- 13 C NMR spectrum; Figure 3 The fluorescent heteropolymer product prepared in Example 1 is cis- 1 H NMR spectrum; Figure 4 The image shows the UV-Vis image of the fluorescent heteropolymer product prepared in Example 1. Figure 5 The image shows the DSC pattern of the fluorescent heteropolymer product prepared in Example 1. Figure 6The fluorescence spectra of the fluorescent heterochain polymer products prepared in Example 1 are shown. a and b are the trans and cis polymer spectra of the 0.1 M solution of polymer structural units, respectively. c is the spectrum of the 0.005 M solution of polymer structural units in the trans and cis states. Figure 7 The fluorescent heteropolymer product prepared in Example 2 1 H NMR spectrum; Figure 8 GPC image of the fluorescent heteropolymer product prepared in Example 2; Figure 9 The fluorescent heteropolymer product prepared in Example 3 1 H NMR spectrum; Figure 10 GPC diagram of the fluorescent heterochain polymer product prepared in Example 3; Figure 11 The fluorescent heteropolymer product prepared in Example 4 1 H NMR spectrum; Figure 12 GPC diagram of the fluorescent heteropolymer product prepared in Example 4; Figure 13 The fluorescent heteropolymer product prepared in Example 5 1 H NMR spectrum; Figure 14 GPC image of the fluorescent heteropolymer product prepared in Example 5; Figure 15 The fluorescent heteropolymer product prepared in Example 6 1 H NMR spectrum; Figure 16 This is a GPC diagram of the fluorescent heteropolymer product prepared in Example 6. Detailed Implementation

[0024] To enable those skilled in the art to better understand and implement the technical solutions of the present invention, the present invention will be further described below in conjunction with specific embodiments and accompanying drawings. However, the embodiments described are not intended to limit the present invention.

[0025] The purpose of this invention is to provide an azophenyl heterochain fluorescent polymer, its preparation method, and its applications. The method primarily uses azophenyl epoxides and cyclic anhydrides as monomers, and obtains the azophenyl heterochain fluorescent polymer through bulk polymerization, melt polymerization, or solution polymerization under the action of organic catalysts and organometallic catalysts. Compared with existing methods, the route provided by this invention has advantages such as inexpensive catalysts, mild reaction conditions, diverse polymer structures and properties, high molecular weight, controllable polymerization reaction, simple operation, excellent polymer fluorescence properties, and the ability to achieve stimulus response. The obtained azophenyl polymer has good solubility in a variety of organic solvents, and its luminescent properties can be modified by adjusting the concentration and inducing photoisomerization of the azophenyl groups, demonstrating good application potential.

[0026] To achieve the above objectives, the first aspect of the present invention provides an azophenyl heterochain fluorescent polymer, the general structural formula of which is as follows:

[0027] In the formula, X is O, S, N or C; R is selected from H, CH3, CH2CH3, (CH2)2CH3, CH(CH3)2, (CH2)3CH3, C(CH3)3, (CH2)4CH3, (CH2)5CH3, (CH2)6CH3, (CH2)7CH3, OCH3, OCH2CH3, N(Me)2, NO2 or CN; Me represents methyl, N(Me2) is an N,N-dimethyl substituent; When X is N, R1 is selected from one of the following:

[0028] R2 is selected from H, CH3, CH2CH3, CH(CH3)2, C(CH3)3, OCH3, OCH2CH3, F, Cl, Br, I or NO2.

[0029] The azophenyl heterochain fluorescent polymer has a number-average molecular weight of 5000~30000 g / mol and a molecular weight distribution of 1.01~1.7.

[0030] The azophenyl heterochain fluorescent polymer undergoes repeated cis-trans isomerization under irradiation with ultraviolet light at wavelengths of 365–385 nm and visible light at wavelengths of 410–450 nm. The cis-trans isomerization pathway is as follows: .

[0031] A second aspect of this invention provides a method for preparing an azophenyl heterochain fluorescent polymer, comprising the following steps: Using azobenzene epoxyalkane and cyclic acid anhydride as raw materials, azobenzene heterochain fluorescent polymers are obtained through bulk polymerization, melt polymerization or solution polymerization under the action of a catalyst. The azobenzene epoxy alkane is selected from one or more of the following:

[0032] Where n = 0~7.

[0033] The synthetic route for the azophenyl heterochain fluorescent polymer is as follows: (The original text contains some inconsistencies and inconsistencies. A more accurate translation would require the full context.) ; The cyclic anhydride is selected from one or more of the following: .

[0034] The catalyst includes organic catalysts and organometallic catalysts; The organic catalyst is one or more of the following:

[0035]

[0036] Wherein, A is one of Cl, Br, NO3, and OAc; The organometallic catalyst is:

[0037] In the formula, M represents Al. 3+ Fe 3+ Co 3+ Ni 3+ Cr 3+ Mn 3+ Or Ru 3+ ; B is F - Cl - ,Br - I - NO3 - CH3COO - CCl3COO - CF3COO - ClO4 - BF4 - BPh4 - N3 -p-Toluenesulfonate, p-Nitrophenoloxy, p-Nitrophenoloxy, m-Nitrophenoloxy, 2,4-Dinitrophenoloxy, 3,5-Dinitrophenoloxy, 2,4,6-Trinitrophenoloxy, 3,5-Dichlorophenoloxy, 3,5-Difluorophenoloxy, 3,5-Di-trifluoromethylphenoloxy, or pentafluorophenoloxy anions; R 3 for ; R 4 The possible values ​​are H, CH3, CH2CH3, CH(CH3)2, C(CH3)3, OCH3, OCH2CH3, F, Cl, Br, I, or NO2; R 5 The possible values ​​are H, CH3, CH2CH3, CH(CH3)2, C(CH3)3, OCH3, OCH2CH3, F, Cl, Br, I, or NO2.

[0038] The solvent used for solution polymerization is selected from any one of toluene, dioxane, acetonitrile, tetrahydrofuran, and N,N-dimethylformamide.

[0039] The molar ratio of the azobenzene epoxy alkane to the cyclic anhydride is 1:10 to 10:1; the molar ratio of the azobenzene epoxy alkane to the catalyst is 10:1 to 10000:1.

[0040] The reaction temperatures for bulk polymerization, melt polymerization, or solution polymerization are all -20 to 200 °C, and the reaction times are all 0.1 to 96 h.

[0041] It should be noted that bulk polymerization refers to the use of one of the liquid monomers as a solvent, while melt polymerization refers to the use of a monomer that has been heated and melted as a solvent.

[0042] An exemplary method for preparing a tunable heterochain fluorescent polymer includes the following steps: Using substituent azobenzene epoxyalkane and cyclic acid anhydrides as monomers, heterochain fluorescent polymers are obtained through bulk polymerization, melt polymerization or solution polymerization under the action of a catalyst.

[0043] A third aspect of the present invention provides the application of an azophenyl heterochain fluorescent polymer in medicine, bioimaging, ion detection, photolithography, or smart materials.

[0044] It should be noted that, unless otherwise specified, the experimental methods used in this invention are all conventional methods; and the reagents and materials used, unless otherwise specified, are all commercially available.

[0045] The materials used in the following embodiments are shown in Tables 1-4.

[0046] Table 1 lists the azophenyl epoxide compounds used in the following examples.

[0047] Table 2 lists the cyclic anhydride compounds used in the following examples.

[0048] Table 3 lists the organic catalyst compounds used in the following examples.

[0049] Table 4 lists the organometallic catalyst compounds used in the following examples.

[0050] Example 1 A 10 mL pressure-resistant glass bottle equipped with a magnetic stirrer was dried at 100 °C for at least 4 hours, evacuated, and allowed to cool to room temperature before being filled with nitrogen for use. Under nitrogen protection, 5.7 mg of 3a and 6 mg of 4a were weighed at room temperature, and then 381 mg of azophenyl epoxide alkane 1a and 231 mg of cyclic anhydride 2a were added (1a:2a:3a:4a = 75:75:1:1, molar ratio). The above materials were dissolved in 0.7 mL of toluene. The solution was then placed in an oil bath at 100 °C and magnetically stirred. The reaction was allowed to proceed for 2.5 h, after which stirring was stopped. A very small amount of the reaction mixture was taken out for further processing. 1 HNMR and GPC tests. See also Figure 1 and Figure 3 As shown, 1 ¹H NMR analysis showed a conversion rate of 92.4% for azophenyl epoxides, and GPC analysis showed a polymer molecular weight of 14200 g / mol with a molecular weight distribution of 1.22. The remaining polymer was purified by dissolving the crude product in a small amount of dichloromethane, then adding it dropwise to a large amount of methanol while shaking vigorously to precipitate the polymer. Repeated washing with methanol yielded an orange-red polymer. 122 mg of the polymer was dissolved in 3 mL of spectral-grade dichloromethane in a quartz cuvette to obtain a solution with a repeating unit concentration of 0.1 mol / L. The solution was then purified using a 365 nm wavelength UV lamp (20 mW / cm²). 2 Irradiation for 20 min can change the azophenyl group in the polymer from trans to cis. 6.1 mg of the polymer was placed in a quartz cuvette and dissolved in 3 mL of spectral-grade dichloromethane to obtain a solution with a repeating unit concentration of 0.005 mol / L. The solution was then purified using a 365 nm wavelength UV lamp (20 mW / cm²). 2 Irradiation for 1 minute can change the azophenyl group in the polymer from trans to cis.

[0051] The reaction route is as follows: .

[0052] Figure 2 The fluorescent heteropolymer product prepared in Example 1 is trans- 13 C NMR spectrum; Figure 2 There are 16 peaks in the middle, indicating that there are 16 different chemical environments of carbon in the polymer.

[0053] Figure 4 The image shows the UV-Vis spectrum of the fluorescent heteropolymer product prepared in Example 1. When the trans polymer solution is irradiated with ultraviolet light at a wavelength of 365 nm, the π-π* absorption of the polymer at 345 nm gradually decreases, while the n-π absorption of the polymer at 440 nm gradually increases, indicating that the polymer changes from a trans structure to a cis structure. When the cis polymer solution is irradiated with ultraviolet light at a wavelength of 450 nm, the π-π* absorption of the polymer at 345 nm gradually increases, while the n-π absorption of the polymer at 440 nm gradually decreases, indicating that the polymer changes from a cis structure to a trans structure.

[0054] Figure 5 The image shows the DSC pattern of the fluorescent heteropolymer product prepared in Example 1; from Figure 5 It can be seen that the glass transition temperature of trans polymers ( T g The value is 72.6. o C, the glass transition temperature of cis polymers ( T g The value is 11.6 o C, and at 70 o C to 110 o At temperature C, azobenzene changes from cis to trans, resulting in an exothermic peak.

[0055] Figure 6 The images show the fluorescence spectra of the fluorescent heterochain polymer products prepared in Example 1. a and b are the trans and cis polymer spectra of the 0.1 M polymer structural unit solution, respectively, and c is the spectrum of the 0.005 M polymer structural unit solution in the trans and cis configurations. Figure 6 As shown in (a), the 0.1 M trans polymer emits light at a wavelength of 650 nm, and this emission is wavelength-dependent. Figure 6 As shown in (b), when the polymer is converted to a cis structure by irradiation with 365 nm ultraviolet light, the emission wavelength of the 0.1 M polymer is red-shifted to 666 nm and exhibits excitation wavelength dependence. Figure 6 As shown in (c), at 5×10 -3In a low-concentration solution of M, the trans polymer emitted light at a wavelength of 540 nm and an intensity of 50 au. When the polymer was irradiated with 365 nm ultraviolet light, it was converted to a cis polymer. The cis polymer emitted light at a wavelength of 540 nm and an intensity of 12000 au, which was more than 2000 times stronger than that of the trans polymer.

[0056] Example 2 A 10 mL pressure-resistant glass bottle equipped with a magnetic stir bar was dried at 100 °C for at least 4 hours, evacuated, and allowed to cool to room temperature before being filled with nitrogen for use. Under nitrogen protection, 5.7 mg of 3a and 6 mg of 4a were weighed at room temperature, and then 381 mg of azophenyl epoxide alkane 1a and 221.9 mg of isocyanate 2c (1a:2c:3a:4a = 75:75:1:1, molar ratio) were added. The above materials were dissolved in 0.7 mL of toluene. The solution was then placed in an oil bath at 100 °C and magnetically stirred. The reaction was allowed to proceed for 2.5 h, after which stirring was stopped. A very small amount of the reaction mixture was taken out for further processing. 1 HNMR and GPC tests. See also Figure 7 As shown, 1 HNMR analysis showed that the conversion rate of azophenyl epoxide was 91.3%. (See [reference needed]) Figure 8 As shown, GPC testing revealed a polymer molecular weight of 18300 g / mol and a molecular weight distribution of 1.15. The remaining polymer was purified as follows: the crude product was first dissolved in a small amount of dichloromethane, then added dropwise to a large amount of methanol, and the mixture was vigorously shaken to precipitate the polymer. The polymer was repeatedly washed with methanol to obtain an orange-red polymer. 135.5 mg of the polymer was placed in a quartz cuvette and dissolved in 3 mL of spectral-grade dichloromethane to obtain a solution with a repeating unit concentration of 0.1 mol / L. The solution was then analyzed using a 365 nm wavelength UV lamp (20 mW / cm²). 2 Irradiation for 20 min can change the azophenyl group in the polymer from trans to cis. 6.77 mg of the polymer was placed in a quartz cuvette and dissolved in 3 mL of spectral-grade dichloromethane to obtain a solution with a repeating unit concentration of 0.005 mol / L. The solution was then purified using a 365 nm wavelength UV lamp (20 mW / cm²). 2 Irradiation for 1 minute can change the azophenyl group in the polymer from trans to cis.

[0057] The reaction route is as follows: .

[0058] Example 3 A 10 mL pressure-resistant glass bottle equipped with a magnetic stir bar was dried at 100 °C for at least 4 hours, evacuated, and allowed to cool to room temperature before being filled with nitrogen for use. Under nitrogen protection, 5.7 mg of 3a and 6 mg of 4a were weighed at room temperature, and then 426.5 mg of azophenyl epoxide alkane 1b and 233 mg of cyclic anhydride 2d (1b:2d:3a:4a = 75:75:1:1, molar ratio) were added. The above materials were dissolved in 0.7 mL of toluene. The solution was then placed in an oil bath at 100 °C and magnetically stirred. The reaction was allowed to proceed for 2.5 h, after which stirring was stopped. A very small amount of the reaction mixture was taken out for further processing. 1 HNMR and GPC tests. See also Figure 9 As shown, 1 HNMR analysis showed that the conversion rate of azophenyl epoxide was 88.7%. (See [reference needed]) Figure 10 As shown, GPC testing revealed a polymer molecular weight of 16700 g / mol and a molecular weight distribution of 1.14. The remaining polymer was purified. The purification process involved dissolving the crude product in a small amount of dichloromethane, then adding it dropwise to a large amount of methanol while vigorously shaking to precipitate the polymer. Repeated washing with methanol yielded an orange-red polymer. 131.2 mg of the polymer was placed in a quartz cuvette and dissolved in 3 mL of spectral-grade dichloromethane to obtain a solution with a repeating unit concentration of 0.1 mol / L. The solution was then analyzed using a 365 nm wavelength UV lamp (20 mW / cm²). 2 Irradiation for 20 min can change the azophenyl group in the polymer from trans to cis. 6.5 mg of the polymer was placed in a quartz cuvette and dissolved in 3 mL of spectral-grade dichloromethane to obtain a solution with a repeating unit concentration of 0.005 mol / L. The solution was then purified using a 365 nm wavelength UV lamp (20 mW / cm²). 2 Irradiation for 1 minute can change the azophenyl group in the polymer from trans to cis.

[0059] The reaction route is as follows: .

[0060] Example 4 A 10 mL pressure-resistant glass bottle equipped with a magnetic stir bar was dried at 100 °C for at least 4 hours, evacuated, and allowed to cool to room temperature before being filled with nitrogen for use. Under nitrogen protection, 5.7 mg of 3a and 6 mg of 4a were weighed at room temperature, and then 448.9 mg of azophenyl epoxide alkane 1c and 231 mg of cyclic anhydride 2d were added (1c:2d:3a:4a = 75:75:1:1, molar ratio). The above materials were dissolved in 0.7 mL of toluene. The solution was then placed in an oil bath at 100 °C and magnetically stirred. The reaction was allowed to proceed for 2.5 h, after which stirring was stopped. A very small amount of the reaction mixture was taken out for further processing. 1HNMR and GPC tests. See also Figure 11 As shown, 1 HNMR analysis showed that the conversion rate of azophenyl epoxide was 95.3%. (See [reference needed]) Figure 12 As shown, GPC testing revealed a polymer molecular weight of 11800 g / mol and a molecular weight distribution of 1.17. The remaining polymer was purified. The purification process involved dissolving the crude product in a small amount of dichloromethane, then adding it dropwise to a large amount of methanol while vigorously shaking to precipitate the polymer. Repeated washing with methanol yielded an orange-red polymer. 135.5 mg of the polymer was placed in a quartz cuvette and dissolved in 3 mL of spectral-grade dichloromethane to obtain a solution with a repeating unit concentration of 0.1 mol / L. The solution was then purified using a 365 nm wavelength UV lamp (20 mW / cm²). 2 Irradiation for 20 min can change the azophenyl group in the polymer from trans to cis. 6.8 mg of the polymer was placed in a quartz cuvette and dissolved in 3 mL of spectral-grade dichloromethane to obtain a solution with a repeating unit concentration of 0.005 mol / L. The solution was then purified using a 365 nm wavelength UV lamp (20 mW / cm²). 2 Irradiation for 1 minute can change the azophenyl group in the polymer from trans to cis.

[0061] The reaction route is as follows: .

[0062] Example 5 A 10 mL pressure-resistant glass bottle equipped with a magnetic stirrer was dried at 100 °C for at least 4 hours, evacuated, and allowed to cool to room temperature before being filled with nitrogen for use. Under nitrogen protection, 5.7 mg of 3a and 6 mg of 4a were weighed at room temperature, and then 423.5 mg of azophenyl epoxide alkane 1d and 231 mg of cyclic anhydride 2a were added (1d:2a:3a:4a = 75:75:1:1, molar ratio). The above materials were dissolved in 0.7 mL of toluene. The solution was then placed in an oil bath at 100 °C and magnetically stirred. The reaction was allowed to proceed for 2.5 h, after which stirring was stopped. A very small amount of the reaction mixture was taken out for further processing. 1 HNMR and GPC tests. See also Figure 13 As shown, 1 HNMR analysis showed that the conversion rate of azophenyl epoxide was 94.6%. (See [reference needed]) Figure 14As shown, GPC testing revealed a polymer molecular weight of 13300 g / mol and a molecular weight distribution of 1.21. The remaining polymer was purified. The purification process involved dissolving the crude product in a small amount of dichloromethane, then adding it dropwise to a large amount of methanol while vigorously shaking to precipitate the polymer. Repeated washing with methanol yielded an orange-red polymer. 130.4 mg of the polymer was placed in a quartz cuvette and dissolved in 3 mL of spectral-grade dichloromethane to obtain a solution with a repeating unit concentration of 0.1 mol / L. The solution was then analyzed using a 365 nm wavelength UV lamp (20 mW / cm²). 2 Irradiation for 20 min can change the azophenyl group in the polymer from trans to cis. 6.5 mg of the polymer was placed in a quartz cuvette and dissolved in 3 mL of spectral-grade dichloromethane to obtain a solution with a repeating unit concentration of 0.005 mol / L. The solution was then purified using a 365 nm wavelength UV lamp (20 mW / cm²). 2 Irradiation for 1 minute can change the azophenyl group in a polymer from the trans to the cis configuration. The reaction route is as follows: .

[0063] Example 6 A 10 mL pressure-resistant glass bottle equipped with a magnetic stir bar was dried at 100 °C for at least 4 hours, evacuated, and allowed to cool to room temperature before being filled with nitrogen for use. Under nitrogen protection, 5.7 mg of 3a and 6 mg of 4a were weighed at room temperature, and then 423.5 mg of azophenyl epoxide alkane 1d and 233 mg of cyclic anhydride 2b (1d:2b:3a:4a = 75:75:1:1, molar ratio) were added. The above materials were dissolved in 0.7 mL of toluene. The solution was then placed in an oil bath at 100 °C and magnetically stirred. The reaction was allowed to proceed for 2.5 h, after which stirring was stopped. A very small amount of the reaction mixture was taken out for further processing. 1 HNMR and GPC tests. See also Figure 15 As shown, 1 HNMR analysis showed that the conversion rate of azophenyl epoxide was 87.9%. (See [reference needed]) Figure 16 As shown, GPC testing revealed a polymer molecular weight of 17300 g / mol and a molecular weight distribution of 1.09. The remaining polymer was purified as follows: the crude product was first dissolved in a small amount of dichloromethane, then added dropwise to a large amount of methanol, and the mixture was vigorously shaken to precipitate the polymer. The polymer was repeatedly washed with methanol to obtain an orange-red polymer. 130.7 mg of the polymer was placed in a quartz cuvette and dissolved in 3 mL of spectral-grade dichloromethane to obtain a solution with a repeating unit concentration of 0.1 mol / L. The solution was then analyzed using a 365 nm wavelength UV lamp (20 mW / cm²). 2Irradiation for 20 min can change the azophenyl group in the polymer from trans to cis. 6.5 mg of the polymer was placed in a quartz cuvette and dissolved in 3 mL of spectral-grade dichloromethane to obtain a solution with a repeating unit concentration of 0.005 mol / L. The solution was then purified using a 365 nm wavelength UV lamp (20 mW / cm²). 2 Irradiation for 1 minute can change the azophenyl group in a polymer from the trans to the cis configuration. The reaction route is as follows: .

[0064] This invention describes preferred embodiments and their effects. However, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to include both the preferred embodiments and all changes and modifications falling within the scope of this invention.

[0065] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An azophenyl heterochain fluorescent polymer, characterized in that, The general structural formula of the azophenyl heterochain fluorescent polymer is as follows: In the formula, X is O, S, N or C; R is selected from H, CH3, CH2CH3, (CH2)2CH3, CH(CH3)2, (CH2)3CH3, C(CH3)3, (CH2)4CH3, (CH2)5CH3, (CH2)6CH3, (CH2)7CH3, OCH3, OCH2CH3, N(Me)2, NO2 or CN; When X is N, R1 is selected from one of the following: R2 is selected from H, CH3, CH2CH3, CH(CH3)2, C(CH3)3, OCH3, OCH2CH3, F, Cl, Br, I or NO2.

2. The azophenyl heterochain fluorescent polymer according to claim 1, characterized in that, The azophenyl heterochain fluorescent polymer has a number-average molecular weight of 5000~30000 g / mol and a molecular weight distribution of 1.01~1.

7.

3. The azophenyl heterochain fluorescent polymer according to claim 1, characterized in that, The azophenyl heterochain fluorescent polymer undergoes repeated cis-trans isomerization under irradiation with ultraviolet light at wavelengths of 365–385 nm and visible light at wavelengths of 410–450 nm. The cis-trans isomerization pathway is as follows: 。 4. A method for preparing the azophenyl heterochain fluorescent polymer according to any one of claims 1 to 3, characterized in that, Includes the following steps: Using azobenzene epoxyalkane and cyclic acid anhydride as raw materials, azobenzene heterochain fluorescent polymers are obtained through bulk polymerization, melt polymerization or solution polymerization under the action of a catalyst. The azobenzene epoxy alkane is selected from one or more of the following: Where n = 0~7.

5. The method for preparing the azophenyl heterochain fluorescent polymer according to claim 4, characterized in that, The synthetic route for the azophenyl heterochain fluorescent polymer is as follows: (The original text contains some inconsistencies and inconsistencies. A more accurate translation would require the full context.) ； The cyclic anhydride is selected from one or more of the following: 。 6. The method for preparing the azophenyl heterochain fluorescent polymer according to claim 4, characterized in that, The catalyst includes organic catalysts and organometallic catalysts; The organic catalyst is one or more of the following: Wherein, X is one of Cl, Br, NO3, and OAc; The organometallic catalyst is: In the formula, M represents Al. 3+ Fe 3+ Co 3+ Ni 3+ Cr 3+ Mn 3+ Or Ru 3+ ; B is F - Cl - ,Br - I - NO3 - CH3COO - CCl3COO - CF3COO - ClO4 - BF4 - BPh4 - N3 - p-Toluenesulfonate, p-Nitrophenoloxy, p-Nitrophenoloxy, m-Nitrophenoloxy, 2,4-Dinitrophenoloxy, 3,5-Dinitrophenoloxy, 2,4,6-Trinitrophenoloxy, 3,5-Dichlorophenoloxy, 3,5-Difluorophenoloxy, 3,5-Di-trifluoromethylphenoloxy, or pentafluorophenoloxy anions; R 3 for ; R 4 The possible values ​​are H, CH3, CH2CH3, CH(CH3)2, C(CH3)3, OCH3, OCH2CH3, F, Cl, Br, I, or NO2; R 5 The possible values ​​are H, CH3, CH2CH3, CH(CH3)2, C(CH3)3, OCH3, OCH2CH3, F, Cl, Br, I, or NO2.

7. The method for preparing the azophenyl heterochain fluorescent polymer according to claim 4, characterized in that, The solvent used for solution polymerization is selected from any one of toluene, dioxane, acetonitrile, tetrahydrofuran, and N,N-dimethylformamide.

8. The method for preparing the azophenyl heterochain fluorescent polymer according to claim 4, characterized in that, The molar ratio of the azobenzene epoxy alkane to the cyclic anhydride is 1:10 to 10:1; the molar ratio of the azobenzene epoxy alkane to the catalyst is 10:1 to 10000:

1.

9. The method for preparing the azophenyl heterochain fluorescent polymer according to claim 4, characterized in that, The reaction temperatures for bulk polymerization, melt polymerization, or solution polymerization are all -20 to 200 °C, and the reaction times are all 0.1 to 96 h.

10. The application of the azophenyl heterochain fluorescent polymer according to any one of claims 1 to 3 in medicine, bioimaging, ion detection, photolithography, or smart materials.

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