Branched fluorescent polymer and preparation method thereof

Abstract

The invention relates to the technical field of fluorescent polymers, in particular to a branched fluorescent polymer and a preparation method thereof. The solid fluorescence quantum yield of a linear fluorescent polymer obtained by reaction of an amino alcohol monomer and an activated alkyne monomer is difficult to reach more than 30%. Based on the problems, the invention provides a branched fluorescent polymer, a series of branched fluorescent polymers are obtained through a click reaction of an amino alcohol monomer and an activated alkyne monomer, and the solid fluorescence quantum yield of the obtained branched fluorescent polymer is much higher than that of a linear fluorescent polymer. And the level of more than 30% can be easily reached.

Description

Technical Field

[0001] The invention relates to the technical field of fluorescent polymers, and in particular to a branched fluorescent polymer and a preparation method thereof. Background Art

[0002] In the past decade, non-conjugated fluorescent polymers, such as polyamidoamines, polysiloxanes, polyureas, polyethers, and polyphosphates, have been discovered, which can exhibit unexpected luminescent properties under UV excitation. Generally speaking, the abundant electron-rich heteroatom groups (such as amide, C=O, C=N, etc.) in non-conjugated fluorescent polymers can form intramolecular or intermolecular pendant clusters, thereby triggering fluorescence emission. Unlike conjugated fluorescent polymers, non-conjugated fluorescent polymers usually do not produce strong fluorescence because the main absorption is the result of n-π* excitation rather than π-π* excitation.

[0003] The non-conjugated fluorescent polymers constructed by branched polymers not only have the advantages of abundant and available polymer end groups, but also have adjustable chemical structures and fluorescence, which provides a feasibility for designing non-conjugated fluorescent polymers with high fluorescence quantum yield. Therefore, it is of great value to design non-conjugated fluorescent polymers with high fluorescence quantum yield using effective polymerization methods in practical applications.

[0004] Click reaction is an efficient method for synthesizing polymers because of its advantages such as good selectivity, wide application range, mild conditions, high efficiency, no by-products, and atom economy. At present, researchers have achieved the preparation of nitrogen-containing polymers with high yields by click polymerization of nucleophilic amine monomers and unsaturated bond monomers (double bonds or triple bonds) at room temperature and without catalysis. Hydroxyl monomers, like amino monomers, are also a type of commonly used nucleophilic reagents. Compared with amines, alcohol monomers have the advantages of many types, wide sources, good stability, and non-toxicity and no irritating odor. However, the polymerization of alcohol monomers and unsaturated bond monomers usually requires the addition of additional catalysts.

[0005] Using click reactions, the research team of the present invention has developed a variety of linear fluorescent polymer luminescent materials, but the solid fluorescence quantum yield of the obtained linear fluorescent polymers is difficult to reach more than 30%. Summary of the invention

[0006] The problem in the prior art is that the solid fluorescence quantum yield of the linear fluorescent polymer obtained by reacting an amino alcohol monomer with an activated acetylene monomer is difficult to reach more than 30%. In view of the above technical problems, the present invention provides a branched fluorescent polymer, which is generated by an amino alcohol monomer and an acetylene monomer through a click reaction. During the reaction, the acetylene group in the acetylene monomer structure first undergoes a click reaction with the primary amine group or the secondary amine group in the amino alcohol monomer structure, and then undergoes a click reaction with the hydroxyl group in the primary amine alcohol monomer or the secondary amine alcohol monomer structure; both ends of the acetylene monomer molecular chain are capped by two acetylene groups; the amino alcohol monomer includes a primary amine alcohol monomer or a secondary amine alcohol monomer containing at least two hydroxyl groups.

[0007] Preferably, the alkynyl monomer includes a dialkynyl monomer or a polyalkynyl monomer having two alkynyl groups capping both ends of the molecular chain.

[0008] Preferably, the diacetylenic monomer comprises the following structural formula:

[0009]

[0010] In the above structural formula, m is 1-3, and n>2.

[0011] Preferably, the polyacetylenic monomer comprises the following structural formula:

[0012]

[0013] Preferably, the primary amine alcohol monomer includes monohydroxy primary amine alcohol, dihydroxy primary amine alcohol or polyhydroxy primary amine alcohol.

[0014] Preferably, the monohydroxy primary amine alcohol comprises propanolamine or isopropanolamine.

[0015] Preferably, the dihydroxy primary amine alcohol includes diethanolamine, bis(2-hydroxypropyl)amine or N,N'-bis(2-hydroxyethyl)ethylenediamine.

[0016] Preferably, the polyhydroxy primary amine alcohol comprises 1,3-bis[tris(hydroxymethyl)methylamino]propane.

[0017] Preferably, in the click reaction process, the primary amine alcohol monomer is 1,3-bis[tris(hydroxymethyl)methylamino]propane, the alkynyl monomer is ethylene glycol dipropiolate, and the molar ratio of the primary amine alcohol monomer to the alkynyl monomer is 1:2.

[0018] The present invention has the following beneficial effects:

[0019] (1) The present invention obtains a series of branched fluorescent polymers through click reactions between primary amine alcohol or secondary amine alcohol containing at least two hydroxyl groups and activated alkyne monomers, and by optimizing the types of primary amine and secondary amine alcohol, the obtained branched fluorescent polymers all have a higher solid fluorescence quantum yield, which can reach more than 30%, achieving good technical effects;

[0020] (2) The method of the present invention has high atomic utilization rate, good selectivity, and good yield, does not require the use of any catalyst, can react within the temperature range of 0-60°C, and has good market prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 : is the H-NMR spectrum of the fluorescent polymer obtained in Example 1.

[0022] Figure 2 : is the fluorescence spectrum of the fluorescent polymer obtained in Example 1.

[0023] Figure 3 : is the H-NMR spectrum of the fluorescent polymer obtained in Example 2.

[0024] Figure 4 : is the fluorescence spectrum of the fluorescent polymer obtained in Example 2.

[0025] Figure 5 : is the fluorescence spectrum of the fluorescent polymer obtained in Example 3.

[0026] Figure 6 : is the fluorescence spectrum of the fluorescent polymer obtained in Example 4.

[0027] Figure 7 : is the fluorescence spectrum of the fluorescent polymer obtained in Example 5.

[0028] Figure 8 : is the fluorescence spectrum of the fluorescent polymer obtained in Example 6. DETAILED DESCRIPTION

[0029] The present invention is described in detail below with reference to the examples. However, it should be understood that the following examples are only illustrative of the embodiments of the present invention, and are not intended to limit the scope of the present invention.

[0030] All monomers used in the following examples of the present invention are commercially available or can be easily synthesized.

[0031] in,

[0032] Alkyne monomer It can be synthesized according to the method reported in the literature (ACS Appl. Polym. Mater. 2024, 6, 4127-4137).

[0033] Example 1

[0034] Propanolamine (0.075 g, 1 equiv) and ethylene glycol dipropiolate (0.249 g, 1.5 equiv) were added to a 5 mL single-mouth polymerization bottle and stirred in air at 60°C for 24 h. After the reaction was completed, the mixture was precipitated with n-hexane to obtain a hyperbranched fluorescent polymer with a yield of 80% and an E configuration of 98%. The structure of the branched polymer was confirmed by hydrogen nuclear magnetic resonance (see the attached manual). Figure 1 The weight average molecular weight of the polymer characterized by size exclusion chromatography was 18800 g / mol, and the molecular weight distribution was 2.65, indicating that this method can prepare a branched fluorescent polymer with a relatively high molecular weight. The excitation wavelength and emission wavelength of the fluorescent polymer tested by fluorescence spectrometer were 463 nm and 520 nm, respectively, showing yellow fluorescence characteristics (as shown in the attached manual). Figure 2 The solid fluorescence quantum yield is 32.97%.

[0035] The chemical formula involved in the above reaction is as follows:

[0036]

[0037] Example 2

[0038] Isopropanolamine (0.075 g, 1 equiv), ethylene glycol dipropiolate (0.249 g, 1.5 equiv) and dichloromethane (0.3 mL) were added to a 10 mL single-mouth polymerization bottle, and stirred at 60 ° C in an air environment for 24 hours. After the reaction was completed, the polymer was precipitated with n-hexane to obtain a branched fluorescent polymer with a yield of 88% and an E configuration of 99%. The weight average molecular weight of the polymer characterized by size exclusion chromatography was 16200 g / mol, and the molecular weight distribution was 1.89, indicating that this method can prepare a branched fluorescent polymer with a higher molecular weight. Its nuclear magnetic hydrogen spectrum is shown in the attached manual Figure 3 As shown in the fluorescence spectrum, Figure 4 As shown. The fluorescence spectrometer tests the excitation wavelength and emission wavelength of the fluorescent polymer to be 471nm and 523nm respectively, showing yellow fluorescence characteristics, and the solid fluorescence quantum yield is 34.08%.

[0039] The chemical formula involved in the above reaction is as follows:

[0040]

[0041] Example 3

[0042] Diethanolamine (0.105 g, 1 equiv), ethylene glycol dipropiolate (0.249 g, 1.5 equiv) and N,N-dimethylformamide (0.3 mL) were added to a 10 mL single-mouth polymerization bottle, and stirred at 60 ° C in an air environment for 12 hours. After the reaction was completed, the polymer was precipitated with ether to obtain a branched fluorescent polymer with a yield of 88% and an E configuration of 95%. The weight average molecular weight of the polymer characterized by size exclusion chromatography was 24800 g / mol, and the molecular weight distribution was 2.45, indicating that this method can prepare a branched fluorescent polymer with a higher molecular weight. Its fluorescence spectrum is shown in the attached manual Figure 5 The fluorescence spectrometer tests the excitation wavelength and emission wavelength of the branched fluorescent polymer to be 490 nm and 555 nm respectively, showing yellow fluorescence characteristics, and the solid fluorescence quantum yield is 33.73%.

[0043] The chemical formula involved in the above reaction is as follows:

[0044]

[0045] Example 4

[0046] Add bis(2-hydroxypropyl)amine (0.133 g, 1 equiv), ethylene glycol dipropiolate (0.2490 g, 1.5 equiv) and dichloromethane (0.3 mL) into a 10 mL single-mouth polymerization bottle, and stir the reaction at 45 ° C in an air environment for 12 hours. After the reaction is completed, the polymer is precipitated with ether to obtain a branched fluorescent polymer with a yield of 78% and an E configuration of 96%. The weight average molecular weight of the polymer characterized by size exclusion chromatography is 22600 g / mol, and the molecular weight distribution is 2.48, indicating that this method can prepare a branched fluorescent polymer with a higher molecular weight. The structure of the branched fluorescent polymer (as shown in the attached manual) was confirmed by hydrogen nuclear magnetic resonance spectroscopy. Figure 3 The fluorescence spectrometer tested the excitation wavelength and emission wavelength of the fluorescent polymer to be 482nm and 545nm respectively, showing orange fluorescence characteristics (as shown in the attached manual). Figure 6 The solid fluorescence quantum yield is 30.18%.

[0047] The chemical formula involved in the above reaction is as follows:

[0048]

[0049] Example 5

[0050] 1,3-Bis[tris(hydroxymethyl)methylamino]propane (0.282 g, 1 equiv), ethylene glycol dipropiolate (0.2490 g, 1.5 equiv) and dichloromethane (0.3 mL) were added to a 10 mL single-mouth polymerization bottle, and stirred at 45 ° C in an air environment for 12 hours. After the reaction was completed, the polymer was precipitated with ether to obtain a branched fluorescent polymer with a yield of 88%. The weight average molecular weight of the polymer characterized by size exclusion chromatography was 34200 g / mol, and the molecular weight distribution was 3.18, indicating that this method can prepare a branched fluorescent polymer with a higher molecular weight. The excitation wavelength and emission wavelength of the fluorescent polymer tested by fluorescence spectrometer were 423 nm and 484 nm, respectively, showing blue fluorescence characteristics (as shown in the attached manual Figure 7 The solid fluorescence quantum yield is 33.28%.

[0051] The chemical formula involved in the above reaction is as follows:

[0052]

[0053] Example 6

[0054] N,N'-bis(2-hydroxyethyl)ethylenediamine (0.148 g, 1 equiv), ethylene glycol dipropiolate (0.332 g, 2 equiv) and DMF (0.3 mL) were added to a 10 mL single-mouth polymerization bottle, and stirred at 45 °C in an air environment for 12 h. After the reaction was completed, the polymer was precipitated with ether to obtain a branched fluorescent polymer with a yield of 82%. The weight average molecular weight of the polymer characterized by size exclusion chromatography was 39200 g / mol, and the molecular weight distribution was 3.62, indicating that this method can prepare a branched fluorescent polymer with a higher molecular weight. The excitation wavelength and emission wavelength of the fluorescent polymer tested by fluorescence spectrometer were 446 nm and 513 nm, respectively, showing green fluorescence characteristics (as shown in the attached manual Figure 8 The solid fluorescence quantum yield is 36.28%.

[0055] The chemical formula involved in the above reaction is as follows:

[0056]

[0057] Comparative Example 1

[0058] Triethanolamine (0.1492g, 1equiv), ethylene glycol dipropiolate (0.249g, 1.5equiv) and dichloromethane (0.3mL) were added to a 10mL single-mouth polymerization bottle, stirred and reacted at 25°C in an air environment for 12h. After the reaction was completed, the polymer was precipitated with ether to obtain a branched fluorescent polymer (see Example 10 recorded in the specification of Chinese invention patent CN114716659A), with a yield of 88%. The weight average molecular weight of the polymer characterized by size exclusion chromatography was 69200g / mol, and the molecular weight distribution was 3.04. The excitation wavelength and emission wavelength of the fluorescent polymer tested by fluorescence spectrometer were 420nm and 495nm respectively, showing blue-green fluorescence characteristics, and the solid fluorescence quantum yield was 13.52%.

[0059]

[0060] Comparative Example 2

[0061] Triisopropanolamine (0.1912 g, 1 equiv), ethylene glycol dipropiolate (0.1660 g, 1 equiv) and dichloromethane (0.3 mL) were added to a 10 mL single-mouth polymerization bottle, stirred and reacted at 25 ° C in an air environment for 12 h, and then precipitated with ether to obtain a branched fluorescent polymer (see Example 12 recorded in the specification of Chinese invention patent CN114716659A), with a yield of 81%. The weight average molecular weight of the polymer characterized by size exclusion chromatography was 20200 g / mol, and the molecular weight distribution was 2.94. The excitation wavelength and emission wavelength of the fluorescent polymer tested by fluorescence spectrometer were 375 nm and 440 nm, respectively, showing blue fluorescence characteristics, and the solid fluorescence quantum yield was 9.85%.

[0062]

[0063] Based on the above ideal embodiments of the present invention, the relevant staff can make various changes and modifications without departing from the technical concept of the present invention through the above description. The technical scope of the present invention is not limited to the contents of the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A branched fluorescent polymer, characterized in that: It is generated by a click reaction between an amino alcohol monomer and an alkynyl monomer. During the reaction, the alkynyl group in the alkynyl monomer structure first undergoes a click reaction with the primary amine group or the secondary amine group in the amino alcohol monomer structure, and then undergoes a click reaction with the hydroxyl group in the primary amine alcohol monomer or the secondary amine alcohol monomer structure; both ends of the alkynyl monomer molecular chain are capped by two alkynyl groups; the amino alcohol monomer includes a primary amine alcohol monomer or a secondary amine alcohol monomer containing at least two hydroxyl groups.

2. A branched fluorescent polymer according to claim 1, characterized in that: The alkynyl monomer includes a dialkynyl monomer or a polyalkynyl monomer whose molecular chains are terminated by two alkynyl groups.

3. A branched fluorescent polymer according to claim 2, characterized in that: The diacetylenic monomers include the following structural formulas: In the above structural formula, m is 1-3, and n>2.

4. A branched fluorescent polymer according to claim 3, characterized in that: The bis-acetylenic monomer includes ethylene glycol dipropiolate.

5. A branched fluorescent polymer according to claim 2, characterized in that: Polyacetylenic monomers include the following structural formulas:

6. A branched fluorescent polymer according to claim 1, characterized in that: The primary amine alcohol monomer includes monohydroxy primary amine alcohol, dihydroxy primary amine alcohol or polyhydroxy primary amine alcohol.

7. A branched fluorescent polymer according to claim 6, characterized in that: The monohydroxy primary amine alcohol includes propanolamine or isopropanolamine.

8. A branched fluorescent polymer according to claim 6, characterized in that: The dihydroxy primary amine alcohol includes diethanolamine, bis(2-hydroxypropyl)amine or N,N'-bis(2-hydroxyethyl)ethylenediamine.

9. A branched fluorescent polymer according to claim 6, characterized in that: The polyhydroxy primary amine alcohol includes 1,3-bis[tris(hydroxymethyl)methylamino]propane.

10. A branched fluorescent polymer according to claim 1, characterized in that: In the click reaction process, the primary amine alcohol monomer is 1,3-bis[tris(hydroxymethyl)methylamino]propane, the alkynyl monomer is ethylene glycol dipropiolate, and the molar ratio of the primary amine alcohol monomer to the alkynyl monomer is 1:2.

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