Boron-containing oxygen heterocyclic ring polymer as well as preparation method and application thereof

Abstract

The invention discloses a boron-containing oxygen heterocyclic ring polymer as well as a preparation method and application thereof, and relates to the technical field of polymer preparation. The preparation method of the boron-containing oxygen heterocyclic ring polymer comprises the following steps: mixing an aldehyde monomer, an alkyne monomer, a triarylboron monomer, a catalyst and a solvent, and reacting to obtain the boron-containing oxygen heterocyclic ring polymer, the structural general formula of the aldehyde monomer is shown in the specification; the structural general formula of the alkyne monomer is shown in the specification. The structural general formula of the triaryl boron monomer is shown in the specification; according to the preparation method provided by the invention, the novel polymer containing the boron-oxygen heterocyclic ring structure can be conveniently and efficiently generated in situ from simple and easily available monomers, the reaction conditions are mild, the polymerization reaction efficiency is high, and the prepared polymer is high in molecular weight, low in cost and high in yield. The compound has good thermal stability, morphology stability, solubility, film-forming property and aggregation state luminescence property.

Description

A boron-oxygen heterocyclic polymer, its preparation method and application Technical Field

[0001] This invention relates to the field of polymer preparation technology, and in particular to a boron-oxygen heterocyclic polymer, its preparation method, and its application. Background Technology

[0002] Boron-containing heterocyclic polymers are a class of advanced materials with unique structures and powerful functions. The introduction of electron-deficient boron atoms endows these materials with a series of special properties. These boron-containing heterocyclic polymers typically possess high Lewis acidity, reversible covalent bonds, excellent thermal stability, and unique optoelectronic properties. They can not only achieve self-healing and reprocessing through dynamic bonding, but also exhibit strong solid-state fluorescence and electron transport capabilities. Based on these properties, boron-containing heterocyclic polymers have shown significant application value in fields such as organic optoelectronics, chemical sensing, self-healing materials, asymmetric catalysis, and gas adsorption and separation, becoming a key platform connecting the forefront of polymer chemistry and materials science.

[0003] However, current traditional methods for preparing boron-containing heterocyclic polymers have several shortcomings, such as the need for prefunctionalized monomer design, complex and cumbersome synthetic steps, harsh polymerization conditions, and difficulty in simultaneously introducing multiple substituents and a wider variety of heteroatoms. Due to these synthetic limitations, existing boron-containing heterocyclic polymers remain relatively limited in terms of product structure and function. Most reported boron-nitrogen heterocycles contain boron-nitrogen heterocycles; in contrast, polymer systems with a large number of boron-oxygen heterocycles in the main chain are still relatively rare. Therefore, developing a method for efficiently preparing boron-oxygen heterocyclic polymer materials with unique structures and advanced functions is of great value in both academic and industrial fields.

[0004] Therefore, existing technologies still need to be improved and developed. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the purpose of this invention is to provide a boron-oxygen heterocyclic polymer and its preparation method and application, aiming to provide a simple and efficient method to prepare boron-oxygen heterocyclic polymers, so as to solve the problem that it is difficult to prepare polymers with a large number of boron-oxygen heterocycles in the main chain.

[0006] The technical solution of the present invention is as follows: In a first aspect, the present invention provides a method for preparing a boron-oxygen heterocyclic polymer, comprising the following steps: mixing an aldehyde monomer, an alkyne monomer, a triarylboron monomer, a catalyst, and a solvent, and reacting the mixture to obtain the boron-oxygen heterocyclic polymer; the general structural formula of the aldehyde monomer is as follows: , or The general structural formula of the alkyne monomer is: The general structural formula of the triarylboron monomer is: The boron-oxygen heterocyclic polymer is a linear boron-oxygen heterocyclic polymer or a hyperbranched boron-oxygen heterocyclic polymer. The general structural formula of the linear boron-oxygen heterocyclic polymer is shown in formula (1). The general structural formula of the repeating unit of the hyperbranched boron-oxygen heterocyclic polymer is shown in formula (2) or formula (3).

[0007] Wherein, n is an integer between 1 and 200 (e.g., it can be 1, 2, 5, 10, 15, 20, 50, 70, 80, 100, 120, 130, 150, 180, or 200, etc.); Ar is an unsubstituted aryl or substituted aryl; R1, R2, R4, and R5 are each independently an unsubstituted aryl, a substituted aryl, an unsubstituted heteroaryl, a substituted heteroaryl, or an aliphatic group; R3 is a hydrogen atom, a halogen atom, a nitro group, a cyano group, an aliphatic group, an unsubstituted heteroaryl, a substituted heteroaryl, an unsubstituted aryl, a substituted aryl, or a first bioactive fragment, wherein the first bioactive fragment includes one of terpenes, steroids, fatty alcohols, and vitamins.

[0008] For example, the aforementioned aliphatic group can be alkyl (e.g., methyl, ethyl, propyl or tert-butyl), alkylamine, alkoxy (e.g., methoxy, ethoxy), allyl or ester (e.g., methyl ester, ethyl ester, etc.), but is not limited thereto; the aliphatic group can also be a fatty alcohol group.

[0009] The preparation method provided by this invention can conveniently and efficiently generate novel boron-oxygen heterocyclic polymers in situ from readily available monomers. Linear boron-oxygen heterocyclic polymers can be easily prepared using simple dialdehyde monomers, and hyperbranched boron-oxygen heterocyclic polymers can be easily prepared using simple ternary or quaternary aldehyde monomers. The preparation method provided by this invention offers good economic efficiency (the monomers used are abundant and inexpensive, and the catalysts can be readily available metal catalysts), relatively mild reaction conditions, high polymerization efficiency, and high molecular weight (weight-average molecular weight of 23,700–134,100, polymer dispersibility index of 1.75–4.56). It also exhibits good thermal stability, morphological stability, solubility, film-forming properties, and aggregated-state luminescence performance, showing unique potential research value in fluorescence emission, fluoride ion fluorescence detection, and fluorescence lithography patterning based on metals and digital masks. This invention effectively solves the problem of the difficulty in preparing polymers with a large number of boron-oxygen heterocyclic main chains.

[0010] In this invention, firstly, a catalyst activates aldehyde and alkyne monomers to generate a five-membered ring intermediate; then, the triarylboron monomer participates in ring closure to cyclize, yielding the target product.

[0011] Optionally, the catalyst comprises a metal catalyst and a ligand, wherein the metal catalyst comprises at least one of cyclooctadiene nickel, nickel chloride, and nickel acetate; the ligand comprises at least one of tributylphosphine, tri-tert-butylphosphine, triphenylphosphine, trimethylbenzylphosphine, tricyclohexylphosphine, tri(2,4,6-trimethoxyphenyl)phosphine, N-heterocyclic carbene, 1,3-bis(diphenylphosphine)propane, and 4,4'-di-tert-butyl-2,2'-bipyridine; and the solvent comprises at least one of toluene, tetrahydrofuran, dimethyl sulfoxide, N,N-dimethylformamide, acetonitrile, 1,4-dioxane, and 1,2-dichloroethane.

[0012] The catalyst used in this invention is a high-yield metal catalyst, which is highly economical.

[0013] In some embodiments, the molar ratio of the metal catalyst to the ligand is 1:2.

[0014] Optionally, the molar ratio of the aldehyde group in the aldehyde monomer, the alkynyl group in the alkynyl monomer, and the triarylboron monomer is 1:1:(2~5); the molar ratio of the alkynyl monomer to the metal catalyst is 1:(0.1~0.3).

[0015] In this invention, the molar amount of the metal catalyst accounts for 10% to 30% of the molar amount of the acetylene monomer. By changing the amount of metal catalyst, the activity of the polymerization reaction can be improved. Preferably, the molar amount of the metal catalyst accounts for 30% of the molar amount of the acetylene monomer.

[0016] For example, the molar ratio of the aldehyde group in the aldehyde monomer, the alkynyl group in the alkynyl monomer, and the triarylboron monomer can be 1:1:2, 1:1:3, 1:1:3, or 1:1:4, etc.

[0017] In this invention, the relationship between the number of moles of aldehyde groups in the aldehyde monomer and the number of moles of the aldehyde monomer is as follows: For example, when the aldehyde monomer is... At that time, if If it is 1 mmoL, then The aldehyde group in the solution is 2 mmol; when the aldehyde monomer is At that time, if If it is 1 mmol, then The aldehyde group in the sample is 3 mmol. The same logic applies to the other cases.

[0018] In some embodiments, the reaction concentration of the aldehyde monomer is 0.05~0.20 mol / L. For example, the reaction concentration of the aldehyde monomer can be 0.05 mol / L, 0.1 mol / L, 0.15 mol / L, or 0.20 mol / L, etc.

[0019] Optionally, the reaction temperature is 25~125℃ (e.g., 25℃, 30℃, 40℃, 50℃, 60℃, 70℃, 80℃, 90℃, 100℃, 110℃, 120℃ or 125℃, etc.), and the reaction time is 1~24 h (e.g., 1h, 2h, 5h, 10h, 12h, 15h, 18h, 20h, 22h or 24h, etc.).

[0020] Optionally, after the reaction and before obtaining the boron-oxygen heterocyclic polymer, the following steps are further included: adding the reaction solution obtained after the reaction to a precipitant for precipitation, and then filtering and drying; the precipitant includes at least one of petroleum ether, n-hexane, methanol, diethyl ether and acetone.

[0021] The polymer products prepared in this invention are easy to separate; a high-purity boron-oxygen heterocyclic polymer can be obtained simply by precipitating once in a precipitant.

[0022] In this invention, specifically, the reaction solution obtained after the reaction is cooled to room temperature (this step is required when the reaction temperature is higher than room temperature; this step is not required when the reaction temperature is less than or equal to room temperature), diluted with dichloromethane, and simply filtered through neutral alumina to obtain a filtrate. The filtrate is then added to a precipitant for precipitation. After filtration, the precipitate is collected and dried to constant weight to obtain a boron-oxygen heterocyclic polymer.

[0023] Optionally, R1 and R2 are each independently selected from any one of the following structural formulas 1 to 21; R3 is selected from any one of the following structural formulas 22 to 23:

[0024]

[0025]

[0026]

[0027]

[0028]

[0029] ;in, Indicates the connection site; where m and q are each independent integers between 1 and 20, X is C, O, S, or Se, and Y and Z are each independent C, N, O, S, or Se; R 6 R 7 and R 8 Each of the following is independently a hydrogen atom, halogen atom, alkylamine, alkyl, alkoxy, allyl, ester, nitro, cyano, heteroaryl, aryl, or a second bioactive fragment, wherein the second bioactive fragment includes one of terpenes, steroids, fatty alcohols, and vitamins.

[0030] Optionally, R4 is selected from any one of the following structural formulas 24 to 30: ;in, Indicates the connection site; R 6 It can be a hydrogen atom, a halogen atom, an alkylamine, an alkyl group, an alkoxy group, an allyl group, an ester group, a nitro group, a cyano group, a heteroaryl group, an aryl group, or a second bioactive fragment, wherein the second bioactive fragment includes one of terpenes, steroids, fatty alcohols, and vitamins.

[0031] Optionally, R5 is selected from any one of the following structural formulas 31 to 37; ;in, Indicates the connection site.

[0032] In a second aspect, the present invention provides a boron-oxygen heterocyclic polymer, wherein the polymer is prepared by the preparation method described above.

[0033] A third aspect of the present invention provides the application of the boron-oxygen heterocyclic polymer of the present invention as described above in fluorescence emission, fluoride ion detection, and fluorescence lithography patterning.

[0034] In this invention, by utilizing the fluorescence properties of polymerization and the affinity of boron atoms for fluoride ions, the resulting polymer can be used for fluoride ion fluorescence detection; by introducing a photosensitive tetraphenylethylene structure, the resulting polymer can be used in traditional fluorescence lithography and digital mask lithography.

[0035] Beneficial Effects: The preparation method provided by this invention can conveniently and efficiently generate novel boron-oxygen heterocyclic polymers in situ from readily available monomers. Linear boron-oxygen heterocyclic polymers can be easily prepared using simple dialdehyde monomers, and hyperbranched boron-oxygen heterocyclic polymers can be easily prepared using simple ternary or quaternary aldehyde monomers. The preparation method provided by this invention offers good economic efficiency (the monomers used are abundant and inexpensive, and the catalysts can be readily available metal catalysts), relatively mild reaction conditions, high polymerization efficiency, and high molecular weight (weight-average molecular weight of 23,700–134,100, polymer dispersibility index of 1.75–4.56). It also exhibits good thermal stability, morphological stability, solubility, film-forming properties, and aggregated-state luminescence performance, demonstrating unique potential research value in fluorescence emission, fluoride ion fluorescence detection, and fluorescence lithography patterning based on metals and digital masks. This invention effectively solves the problem of the difficulty in preparing polymers with a large number of boron-oxygen heterocyclic main chains. Attached Figure Description

[0036] Figure 1 shows the proton NMR spectrum of the linear boron-containing heterocyclic polymer P1 prepared in Example 1 in deuterated dichloromethane.

[0037] Figure 2 shows the proton NMR spectrum of the linear boron-containing heterocyclic polymer P2 prepared in Example 2 in deuterated dichloromethane.

[0038] Figure 3 shows the proton NMR spectrum of the linear boron-containing heterocyclic polymer P3 prepared in Example 3 in deuterated dichloromethane.

[0039] Figure 4 shows the proton NMR spectrum of the hyperbranched boron-oxygen heterocyclic polymer P4 prepared in Example 4 in deuterated dichloromethane.

[0040] Figure 5 shows the proton NMR spectrum of the hyperbranched boron-containing heterocyclic polymer P5 prepared in Example 5 in deuterated dichloromethane.

[0041] Figure 6 shows the proton NMR spectrum of the hyperbranched boron-containing heterocyclic polymer P6 prepared in Example 6 in deuterated dichloromethane.

[0042] Figure 7(A) shows the photofluorescence emission spectrum of the hyperbranched boron-oxygen heterocyclic polymer P5 prepared in Example 5 for fluoride ion detection, and (B) shows the trend of fluorescence intensity of the hyperbranched boron-oxygen heterocyclic polymer P5 prepared in Example 5 compared with the initial intensity in fluoride ion detection.

[0043] Figure 8(A) shows the photoluminescence curves of the hyperbranched boron-oxygen heterocyclic polymer P6 prepared in Example 6 in tetrahydrofuran solutions with different water contents; (B) shows the aggregation-induced emission curve of the hyperbranched boron-oxygen heterocyclic polymer P6 prepared in Example 6.

[0044] Figure 9 shows the fluorescent lithography pattern of the hyperbranched boron-oxygen heterocyclic polymer P6 prepared in Example 6 under a chromium-plated mask.

[0045] Figure 10 shows the fluorescent lithography pattern obtained under a digital mask for the hyperbranched boron-oxygen heterocyclic polymer P6 prepared in Example 6. Detailed Implementation

[0046] This invention provides a boron-oxygen heterocyclic polymer, its preparation method, and its applications. To make the objectives, technical solutions, and effects of this invention clearer and more explicit, the invention is further described in detail below. It should be understood that the specific embodiments described herein are only for explaining the invention and are not intended to limit the invention.

[0047] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0048] The present invention will be further described below through specific embodiments.

[0049] Unless otherwise specified, the raw materials used in the following embodiments are all commercially available products.

[0050] In the following examples, 4'-((1,6-hexane-1,1-diyl)bis(oxy))bis(1-hexyn-1-ylbenzene) was prepared according to the method disclosed in the literature (Gao, M.; Lam, JWY; Liu, Y.; Li, J.; Tang, BZ Polymer Chemistry 2013, 4 (9), 2841-2849.).

[0051] 1,4-Di(prop-1-yn-1-yl)benzene was prepared according to the method disclosed in the literature (Gao, M.; Lam, JWY; Liu, Y.; Li, J.; Tang, BZ Polymer Chemistry 2013, 4 (9), 2841-2849.).

[0052] 1,4-Di(1-propynyl)benzene was prepared according to the method disclosed in the literature (Gao, M.; Lam, JWY; Liu, Y.; Li, J.; Tang, BZ Polymer Chemistry 2013, 4 (9), 2841-2849.).

[0053] Example 1 This example provides a linear boron-oxygen heterocyclic polymer (i.e., linear boron-oxygen heterocyclic polymer P1), whose structural formula is: .

[0054] This embodiment also provides a method for preparing the above-mentioned linear boron-oxygen heterocyclic polymer P1, including the following steps:

[0055] Following the above synthetic route (Bu for tert-butyl, Ph for phenyl), 4,4'-((1,6-hexane-1,1-diyl)bis(oxy))dibenzaldehyde (32.6 mg, 0.10 mmol), 4,4'-((1,6-hexane-1,1-diyl)bis(oxy))bis(1-hexyn-1-ylbenzene) (43.1 mg, 0.10 mmol), triphenylboron (96.8 mg, 0.40 mmol), Ni(cod)2 (8.3 mg, 30 mol%), and tributylphosphine (15 μL, 60 mol%) were sequentially added to a 25 mL sealed tube. Then, in a nitrogen glove box, tetrahydrofuran (THF, 1 mL) was added to the tube, and the mixture was stirred at 125 °C for 24 hours in an oil bath.

[0056] After the reaction was complete, the mixture was cooled to room temperature and diluted with dichloromethane (2 mL). Then, the solution was precipitated by dropwise addition to 150 mL of petroleum ether under vigorous stirring through a 4 cm thick neutral Al₂O₃ column, and the precipitate was collected. The precipitate was then dried under vacuum at 65 °C to constant weight to obtain a linear boron-oxygen heterocyclic polymer P1 with a yield of 99%, a weight-average molecular weight of 32600 g / mol, and a polymer dispersibility index (PDI) of 1.94.

[0057] The proton NMR spectrum of the linear boron-oxygen heterocyclic polymer P1 prepared in Example 1 in deuterated dichloromethane is shown in Figure 1. As can be seen from Figure 1, the solvent peak of deuterated dichloromethane is located at 5.32 ppm. All other peaks represent hydrogen atom signals from the linear boron-oxygen heterocyclic polymer P1, and the characteristic hydrogen atom signals can be assigned accordingly.

[0058] Example 2 This example provides a linear boron-oxygen heterocyclic polymer (i.e., linear boron-oxygen heterocyclic polymer P2), whose structural formula is: .

[0059] This embodiment also provides a method for preparing the above-mentioned linear boron-oxygen heterocyclic polymer P2, including the following steps:

[0060] Following the above synthetic route, 4,4'-oxodibenzaldehyde (22.6 mg, 0.10 mmol), 4,4'-((1,6-hexane-1,1-diyl)bis(oxo))bis(1-hexyn-1-ylbenzene) (43.1 mg, 0.10 mmol), triphenylboron (96.8 mg, 0.40 mmol), Ni(cod)2 (8.3 mg, 30 mol%), and tributylphosphine (15 μL, 60 mol%) were sequentially added to a 25 mL sealed tube. Then, in a nitrogen glove box, THF (1 mL) was added to the tube, and the mixture was stirred at 125 °C for 24 hours in an oil bath.

[0061] After the reaction was complete, the mixture was cooled to room temperature and diluted with dichloromethane (2 mL). The filtrate was then precipitated by dropwise addition to 150 mL of petroleum ether under vigorous stirring through a 4 cm thick neutral Al₂O₃ column, and the precipitate was collected. The precipitate was then dried under vacuum at 65 °C to constant weight to obtain the linear boron-oxygen heterocyclic polymer P₂ in 82% yield, with a weight-average molecular weight of 77,500 g / mol and a PDI of 2.56.

[0062] The proton NMR spectrum of the linear boron-oxygen heterocyclic polymer P2 prepared in Example 2 in deuterated dichloromethane is shown in Figure 2. As can be seen from Figure 2, the solvent peak of deuterated dichloromethane is located at 5.32 ppm. All other peaks represent hydrogen atoms from the linear boron-oxygen heterocyclic polymer P2.

[0063] Example 3 This example provides a linear boron-oxygen heterocyclic polymer (linear boron-oxygen heterocyclic polymer P3), whose structural formula is: .

[0064] This embodiment also provides a method for preparing the above-mentioned linear boron-oxygen heterocyclic polymer P3, including the following steps:

[0065] Following the above synthetic route (Me being methyl), 4,4'-((1,6-hexane-1,1-diyl)bis(oxy))dibenzaldehyde (32.6 mg, 0.10 mmol), 1,4-bis(prop-1-yn-1-yl)benzene (15.4 mg, 0.10 mmol), triphenylboron (96.8 mg, 0.40 mmol), Ni(cod)2 (8.3 mg, 30 mol%), and tributylphosphine (15 μL, 60 mol%) were sequentially added to a 25 mL sealed tube. Then, in a nitrogen glove box, THF (1 mL) was added to the tube, and the mixture was stirred at 125 °C for 24 hours in an oil bath.

[0066] After the reaction was complete, the mixture was cooled to room temperature and diluted with dichloromethane (2 mL). The filtrate was then passed dropwise through a 4 cm thick neutral Al₂O₃ column with vigorous stirring into 150 mL of petroleum ether to precipitate the product. The precipitate was collected and dried under vacuum at 65 °C to constant weight to obtain the linear boron-oxygen heterocyclic polymer P3 in 99% yield, with a weight-average molecular weight of 58,000 g / mol and a PDI of 2.81.

[0067] The proton NMR spectrum of the linear boron-oxygen heterocyclic polymer P3 prepared in Example 3 in deuterated dichloromethane is shown in Figure 3. As can be seen from Figure 3, the solvent peak of deuterated dichloromethane is located at 5.32 ppm. All other peaks represent hydrogen atoms from the linear boron-oxygen heterocyclic polymer P3.

[0068] Example 4 This example provides a hyperbranched boron-oxygen heterocyclic polymer (hyperbranched boron-oxygen heterocyclic polymer P4), whose structural formula is:

[0069] This embodiment also provides a method for preparing the above-mentioned hyperbranched boron-oxygen heterocyclic polymer P4, including the following steps:

[0070] Benzene-1,3,5-tricarboxaldehyde (10.8 mg, 0.067 mmol), 4,4'-((1,6-hexane-1,1-diyl)bis(oxy))bis(1-hexyn-1-ylbenzene) (43.1 mg, 0.10 mmol), triphenylboron (96.8 mg, 0.40 mmol), Ni(cod)2 (8.3 mg, 30 mol%), and tributylphosphine (15 μL, 60 mol%) were added sequentially to a 25 mL sealed tube. Subsequently, in a nitrogen glove box, 1 mL of THF was added to the tube, and the mixture was stirred at 125 °C for 5 minutes in an oil bath. Then, 100 μL of the end-capping agent 1-hexyn-1-ylbenzene was added to the reaction tube, and the mixture was stirred at 125 °C for 1 hour in an oil bath. (Because the product has a hyperbranched structure, its molecular chains are prone to cross-linking, leading to gelation. Therefore, after 5 minutes of reaction, an excess of end-capping agent was added, and the reaction was continued for 1 hour to ensure the polymerization reaction proceeded while avoiding the inability to obtain a soluble polymer due to gelation.)

[0071] After the reaction was complete, the mixture was cooled to room temperature and diluted with dichloromethane (2 mL). The filtrate was then precipitated by dropwise addition to 150 mL of petroleum ether through a 4 cm thick neutral Al₂O₃ column with vigorous stirring, and the precipitate was collected. The precipitate was then dried under vacuum at 65 °C to constant weight to obtain the hyperbranched boron-oxygen heterocyclic polymer P4 in 92% yield, with a weight-average molecular weight of 107,900 g / mol and a PDI of 4.56.

[0072] The proton NMR spectrum of the hyperbranched boron-oxygen heterocyclic polymer P4 prepared in Example 4 in deuterated dichloromethane is shown in Figure 4. As can be seen from Figure 4, the solvent peak of deuterated dichloromethane is located at 5.32 ppm. All other peaks represent hydrogen atoms from the hyperbranched boron-oxygen heterocyclic polymer P4.

[0073] Example 5 This example provides a hyperbranched boron-oxygen heterocyclic polymer (hyperbranched boron-oxygen heterocyclic polymer P5), whose structural formula is: .

[0074] This embodiment also provides a method for preparing the above-mentioned hyperbranched boron-oxygen heterocyclic polymer P5, including the following steps:

[0075] Following the above synthetic route, 4,4',4''-aminotribenzaldehyde (21.9 mg, 0.067 mmol), 4,4'-((1,6-hexane-1,1-diyl)bis(oxy))bis(1-hexyn-1-ylbenzene) (43.1 mg, 0.10 mmol), triphenylboron (96.8 mg, 0.40 mmol), Ni(cod)2 (8.3 mg, 30 mol%), and tributylphosphine (15 μL, 60 mol%) were sequentially added to a 25 mL sealed tube. Then, in a nitrogen glove box, THF (1 mL) was added to the tube, and the mixture was stirred at 25 °C for 5 hours. Next, the end-capping agent 1-hexyn-1-ylbenzene (100 μL) was added to the reaction tube, and the mixture was stirred at 25 °C for another 1 hour.

[0076] After the reaction was complete, the mixture was cooled to room temperature and diluted with dichloromethane (2 mL). The filtrate was then precipitated by dropwise addition to 150 mL of petroleum ether through a 4 cm thick neutral Al₂O₃ column with vigorous stirring, and the precipitate was collected. The precipitate was then dried under vacuum at 65 °C to constant weight to obtain the hyperbranched boron-oxygen heterocyclic polymer P5 in 82% yield, with a weight-average molecular weight of 64,100 g / mol and a PDI of 2.53.

[0077] The proton NMR spectrum of the hyperbranched boron-oxygen heterocyclic polymer P5 prepared in Example 5 in deuterated dichloromethane is shown in Figure 5. As can be seen from Figure 5, the solvent peak of deuterated dichloromethane is located at 5.32 ppm. All other peaks represent hydrogen atom signals from the hyperbranched boron-oxygen heterocyclic polymer P5.

[0078] Example 6 This example provides a hyperbranched boron-oxygen heterocyclic polymer (i.e., hyperbranched boron-oxygen heterocyclic polymer P6), whose structural formula is as follows: .

[0079] This embodiment also provides a method for preparing the above-mentioned hyperbranched boron-oxygen heterocyclic polymer P6, including the following steps:

[0080] Following the above synthetic route, 4,4',4'',4'''-(ethylene-1,1,2,2-tetramethyl)tetrabenzaldehyde (22.2 mg, 0.05 mmol), 1,4-bis(1-propynyl)benzene (15.4 mg, 0.10 mmol), triphenylboron (96.8 mg, 0.40 mmol), Ni(cod)2 (8.3 mg, 30 mol%), and tributylphosphine (15 μL, 60 mol%) were sequentially added to a 25 mL sealed tube. Then, in a nitrogen glove box, THF (1 mL) was added to the tube, and the mixture was stirred at 125 °C for 1 hour. Next, the end-capping agent 1-hexyn-1-ylbenzene (100 μL) was added to the reaction tube, and the mixture was stirred again at 125 °C for 1 hour.

[0081] After the reaction was complete, the mixture was cooled to room temperature and diluted with dichloromethane (2 mL). The filtrate was then precipitated by dropwise addition to 150 mL of petroleum ether through a 4 cm thick neutral Al₂O₃ column with vigorous stirring, and the precipitate was collected. The precipitate was then dried under vacuum at 65 °C to constant weight to obtain the hyperbranched boron-oxygen heterocyclic polymer P6 in 99% yield, with a weight-average molecular weight of 132,400 g / mol and a PDI of 2.82.

[0082] The proton NMR spectrum of the hyperbranched boron-oxygen heterocyclic polymer P6 prepared in Example 6 in deuterated dichloromethane is shown in Figure 6. As can be seen from Figure 6, the solvent peak of deuterated dichloromethane is located at 5.32 ppm. All other peaks represent hydrogen atom signals from the hyperbranched boron-oxygen heterocyclic polymer P6.

[0083] Fluoride ion detection was performed using the hyperbranched boron-oxygen heterocyclic polymer P5 prepared in Example 5. Specifically, tetrabutylammonium fluoride was added to water to prepare solutions with different fluoride ion concentrations. The hyperbranched boron-oxygen heterocyclic polymer P5 was added to a mixed solvent of tetrahydrofuran and water (volume ratio of tetrahydrofuran to water was 1:9) to form several polymer solutions of the same concentration. Then, different concentrations of fluoride ion solutions were added to each solution, and emission spectra were performed. The results are shown in Figure 7. Figure 7(A) shows the photofluorescence emission spectrum of the hyperbranched boron-oxygen heterocyclic polymer P5 prepared in Example 5 for fluoride ion detection. It can be seen that the fluorescence intensity of the polymer system decreases with increasing fluoride ion concentration. Figure 7(B) shows the trend of fluorescence intensity of the hyperbranched boron-oxygen heterocyclic polymer P5 prepared in Example 5 compared to the initial intensity during fluoride ion detection. The fluorescence intensity decreased rapidly in the initial stage, and the decreasing trend of fluorescence intensity tended to level off as the fluoride ion concentration continued to increase. It is evident that polymer P5 can be used for fluoride ion concentration detection.

[0084] The photoluminescence properties of the hyperbranched boron-oxygen heterocyclic polymer P6 prepared in Example 6 were tested in tetrahydrofuran solutions with different water contents. The results are shown in Figure 8. In Figure 8, (A) is the photoluminescence curve of the hyperbranched boron-oxygen heterocyclic polymer P6 prepared in Example 6 in tetrahydrofuran solutions with different water contents; (B) is the aggregation-induced emission curve of the hyperbranched boron-oxygen heterocyclic polymer P6 prepared in Example 6. As the water content of the undesirable solvent increases, the fluorescence intensity of the system increases significantly, reaching its highest value when the water content is 90%.

[0085] Figure 9 shows the polymer film prepared on a silicon wafer by the hyperbranched boron-oxygen heterocyclic polymer P6 obtained in Example 6 using a spin coater, and the fluorescent lithography pattern obtained under strong ultraviolet light using a chromium-plated mask. By changing the mask pattern, clear fluorescent lithography patterns with different shapes and sizes can be easily obtained.

[0086] Figure 10 shows the polymer film prepared on a silicon wafer by the hyperbranched boron-oxygen heterocyclic polymer P6 obtained in Example 6 using a spin coater. Customizable fluorescent lithography patterns with different shapes, sizes and luminescence intensities were obtained by controlling the irradiation shape, irradiation time and intensity of ultraviolet light in different regions using digital mask technology.

[0087] In summary, this invention provides a boron-oxygen heterocyclic polymer, its preparation method, and its applications. The preparation method provided by this invention can conveniently and efficiently generate novel boron-oxygen heterocyclic polymers in situ using readily available monomers. Linear boron-oxygen heterocyclic polymers can be easily prepared using simple dialdehyde monomers, and hyperbranched boron-oxygen heterocyclic polymers can be easily prepared using simple ternary or quaternary aldehyde monomers. The preparation method provided by this invention offers good economic efficiency (the monomers used are abundant and inexpensive, and the catalysts can be readily available metal catalysts), relatively mild reaction conditions, and high polymerization efficiency. All prepared boron-oxygen heterocyclic polymers have high molecular weights (weight-average molecular weight of 23,700–134,100, polymer dispersibility index of 1.75–4.56), and exhibit good thermal stability, morphological stability, solubility, film-forming properties, and aggregated-state luminescence properties. They have unique potential research value in fluoride ion fluorescence detection, metal-based and digital mask-based fluorescent lithography patterning. This invention effectively solves the problem of the difficulty in preparing polymers with a large number of boron-oxygen heterocyclic main chains.

[0088] It should be understood that the application of the present invention is not limited to the examples above. Those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A method for preparing a boron-oxygen heterocyclic polymer, characterized in that, The process includes the following steps: mixing an aldehyde monomer, an alkyne monomer, a triarylboron monomer, a catalyst, and a solvent, reacting the mixture to obtain the boron-oxygen heterocyclic polymer; the general structural formula of the aldehyde monomer is... 、 or The general structural formula of the alkyne monomer is: The general structural formula of the triarylboron monomer is: The boron-oxygen heterocyclic polymer is a linear boron-oxygen heterocyclic polymer or a hyperbranched boron-oxygen heterocyclic polymer. The general structural formula of the linear boron-oxygen heterocyclic polymer is shown in formula (1). The general structural formula of the repeating unit of the hyperbranched boron-oxygen heterocyclic polymer is shown in formula (2) or formula (3). Wherein, n is an integer between 1 and 200; Ar is an unsubstituted aryl or substituted aryl; R1, R2, R4 and R5 are each independently an unsubstituted aryl, a substituted aryl, an unsubstituted heteroaryl, a substituted heteroaryl or an aliphatic group; R3 is a hydrogen atom, a halogen atom, a nitro, a cyano, an aliphatic group, an unsubstituted heteroaryl, a substituted heteroaryl, an unsubstituted aryl, a substituted aryl or a first bioactive fragment, wherein the first bioactive fragment includes one of terpenes, steroids, fatty alcohols and vitamins.

2. The preparation method according to claim 1, characterized in that, The catalyst comprises a metal catalyst and a ligand, wherein the metal catalyst comprises at least one of cyclooctadiene nickel, nickel chloride, and nickel acetate; the ligand comprises at least one of tributylphosphine, tri-tert-butylphosphine, triphenylphosphine, trimethylbenzylphosphine, tricyclohexylphosphine, tri(2,4,6-trimethoxyphenyl)phosphine, N-heterocyclic carbene, 1,3-bis(diphenylphosphine)propane, and 4,4'-di-tert-butyl-2,2'-bipyridine; and the solvent comprises at least one of toluene, tetrahydrofuran, dimethyl sulfoxide, N,N-dimethylformamide, acetonitrile, 1,4-dioxane, and 1,2-dichloroethane.

3. The preparation method according to claim 2, characterized in that, The molar ratio of the aldehyde group in the aldehyde monomer, the alkynyl group in the alkynyl monomer, and the triarylboron monomer is 1:1:(2~5); the molar ratio of the alkynyl monomer to the metal catalyst is 1:(0.1~0.3).

4. The preparation method according to claim 1, characterized in that, The reaction temperature is 25~125 ℃, and the reaction time is 1~24 h.

5. The preparation method according to claim 1, characterized in that, The reaction process, before obtaining the boron-oxygen heterocyclic polymer, further includes the following steps: adding the reaction solution obtained after the reaction to a precipitant for precipitation, followed by filtration and drying; the precipitant includes at least one of petroleum ether hexane, methanol, diethyl ether, and acetone.

6. The preparation method according to claim 1, characterized in that, R1 and R2 are each independently selected from any one of the following structural formulas 1 to 21; R3 is selected from any one of the following structural formulas 22 to 23: ;in, Indicates the connection site; where m and q are each independent integers between 1 and 20, X is C, O, S, or Se, and Y and Z are each independent C, N, O, S, or Se; R 6 R 7 and R 8 Each of the following is independently a hydrogen atom, halogen atom, alkylamine, alkyl, alkoxy, allyl, ester, nitro, cyano, heteroaryl, aryl, or a bioactive fragment, wherein the bioactive fragment includes one of terpenes, steroids, fatty alcohols, and vitamins.

7. The preparation method according to claim 1, characterized in that, R4 is selected from any one of the following structural formulas 24 to 30: ;in, Indicates the connection site; R 6 It can be a hydrogen atom, halogen atom, alkylamine, alkyl, alkoxy, allyl, ester, nitro, cyano, heteroaryl, aryl, or a bioactive fragment, wherein the bioactive fragment includes one of terpenes, steroids, fatty alcohols, and vitamins.

8. The preparation method according to claim 1, characterized in that, R5 is selected from any one of the following structural formulas 31 to 37; ;in, Indicates the connection site.

9. A boron-oxygen heterocyclic polymer, characterized in that, It is prepared by the preparation method according to any one of claims 1-8.

10. The application of the boron-oxygen heterocyclic polymer of claim 9 in fluorescence emission, fluoride ion detection and fluorescence lithography patterning.

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