Method for regulating and controlling sequential red shift of emission wavelength of fatty amine type non-traditional fluorescent polymer

Abstract

The invention relates to the technical field of fluorescent sensors, in particular to a method for regulating and controlling sequential red shift of emission wavelengths of fatty amine type non-traditional fluorescent polymers. At present, a method for regulating and controlling the sequential change of the fluorescence color of the aliphatic amine type non-conjugated fluorescent polymer from blue light to red light is lacked. In order to solve the technical problem, the invention provides the method for regulating and controlling the sequential red shift of the emission wavelength of the fatty amine type non-traditional fluorescent polymer. By sequentially changing the length of a straight-chain secondary amine alcohol carbon chain, the variety of substituent groups on an amino group and the relative position of the amino group on a carbocyclic ring and an alkyl alcohol hydroxyl group in reaction raw materials, the aliphatic amine type non-traditional fluorescent polymer is subjected to sequential red shift according to an adjustment sequence, and the method is simple, controllable, environment-friendly and high in yield. Good application prospects are realized in the fields of fluorescence sensors, biomedical imaging, photodynamic therapy and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of fluorescence sensors, and particularly to a method for sequentially red-shifting the emission wavelength of a non-conventional fluorescent polymer of the fatty amine type. Background Art

[0002] In recent years, with the rapid development of polymer luminescent materials, traditional conjugated fluorescent materials (such as polymers containing polycyclic aromatic hydrocarbons or heteroaromatic ring structures) have gradually exposed limitations such as complex preparation processes, poor biocompatibility, and insufficient environmental stability due to their luminescence mechanism relying on the π-π conjugation system. Against this background, a class of non-conjugated polymers without polycyclic or heteroaromatic rings has received extensive attention due to their unique aggregation-induced photoluminescence phenomenon, and is called non-conventional novel luminescent materials. Such materials generate fluorescence through intramolecular or intermolecular non-conjugated interactions (such as steric hindrance, hydrogen bonds, clustering effects, etc.) in the aggregated state, showing a completely different luminescence mechanism from traditional materials, and having significant advantages such as simple preparation, adjustable structure, excellent hydrophilicity, and outstanding biocompatibility, becoming ideal candidate materials in the fields of fluorescence sensors, biomedical imaging, photodynamic therapy, etc.

[0003] Current research shows that non-conjugated polymers (such as polyamides, polyethyleneimines, polyethers, etc.) can achieve luminescence through the following mechanisms:

[0004] Clusteroluminescence: Lone pair electrons (such as N, O atoms) or functional groups (such as hydroxyl groups, amino groups) in the molecular chain form dense electron clouds in the aggregated state, generating fluorescence through space conjugation or charge transfer.

[0005] Dynamic bonding interactions: Dynamic crosslinking such as hydrogen bonds and ionic interactions can regulate luminescence properties.

[0006] Excited state intramolecular proton transfer (ESIPT): Some polymers containing amino or hydroxyl groups can achieve Stokes shift through proton transfer.

[0007] Such materials have been successfully applied to biological labeling, cell imaging, and drug delivery systems. For example, polyethyleneimine (PEI) derivatives show potential in in vivo imaging due to their good water solubility and low toxicity.

[0008] Although non-conventional luminescent materials have significant advantages, their ability to regulate luminescence color is severely limited, specifically manifested as:

[0009] Narrow emission wavelength range: Existing materials mostly focus on the blue or green light region (400 - 550 nm), lacking means to cover the entire visible light spectrum (especially red light, 600 - 700 nm).

[0010] Unclear structure-property relationship: The luminescence mechanism of non-conjugated systems is complex. The effects of the types of functional groups, the topological structure of the molecular chain (such as linear, branched, hyperbranched), and the aggregated microenvironment (such as crystallinity, chain spacing) on the luminescence color have not been systematically elucidated.

[0011] Regulation challenges of aliphatic amine polymers: Polymers of the aliphatic amine type (such as tertiary amine groups) have excellent biocompatibility and pH responsiveness, but their emission wavelengths are mostly limited to the blue-green light region (450 - 520 nm). Strategies for red-shifting to the red light region through chemical modification or physical means have not been reported.

[0012] Insufficient dynamic range: Existing methods (such as changing the solvent polarity, regulating the pH value) can only achieve a limited wavelength shift (<50 nm), which is difficult to meet the requirements of wide spectral coverage for applications such as multicolor labeling and anti-counterfeiting coding.

[0013] The root cause of the above problems lies in the essential difference in the luminescence mechanism between non-conjugated systems and traditional materials:

[0014] Lack of energy level regulation of the conjugated backbone: Traditional π-π conjugated materials can directly adjust the energy gap by extending the conjugation length or introducing substituents, while non-conjugated systems rely on local electronic states and clustering effects, significantly increasing the difficulty of energy level regulation.

[0015] Coupled influence of multiple factors: The luminescence performance is affected by the synergistic action of multiple factors such as the electronic properties of functional groups, the conformation of the molecular chain, and the stacking mode of the aggregated state. Changing a single structural parameter is difficult to achieve a large-range wavelength adjustment. Summary of the Invention

[0016] The problems existing in the prior art are as follows: Currently, there is a lack of a method for regulating the sequential change of the fluorescence color of non-conjugated fluorescent polymers from blue light to red light. To address the above technical problems, the present invention provides a method for regulating the sequential red-shift of the emission wavelength of aliphatic amine-type non-conventional fluorescent polymers, and the aliphatic amine-type non-conventional fluorescent polymers include the following general structural formula:

[0017]

[0018] The above-mentioned aliphatic amine-type non-conventional fluorescent polymers are products obtained by the room-temperature click reaction of the hydroxyl group of aliphatic primary amine alcohol or aliphatic secondary amine alcohol with the alkynyl group of ethylene glycol dipropargylate or dipropargyl acetamide. The value of n is determined by the raw material dosage and reaction conditions in the click reaction. In the above general structural formula, the value range of m is 2 - 6, m is an integer, and R1 includes a straight-chain alkyl group, a cycloalkyl group, or an aryl group;

[0019] By sequentially changing the value of m or the type of R1 substituent, the maximum absorption peak and emission peak of the above-mentioned aliphatic amine-type non-conventional fluorescent polymers undergo sequential red-shifts.

[0020] Preferably, the aliphatic secondary amine alcohol includes the following structural formula:

[0021]

[0022] In the above structural formula, R1 includes a straight-chain alkyl group, a cycloalkyl group or an aryl group; the aliphatic secondary amine alcohol is a straight-chain secondary amine alcohol, and the value range of m is 2-6, and m is an integer.

[0023] Preferably, R1 includes one of phenyl, cyclohexyl, methyl, ethyl, isopropyl, and tert-butyl.

[0024] Preferably, the aliphatic primary amine alcohol includes the following structural formula:

[0025]

[0026] In the above structural formula, the value range of m is 2-6, and m is an integer.

[0027] Preferably, for Formula I, when m = 2 and the molar ratio of the aliphatic secondary amine alcohol to ethylene glycol dipropargylate is 1:1, when R1 is sequentially adjusted to methyl, ethyl, isopropyl, tert-butyl, cyclohexyl or phenyl in sequence, the maximum excitation wavelength and the maximum emission wavelength of the obtained fatty amine type non-conventional fluorescent polymer are successively red-shifted.

[0028] Preferably, for Formula II, when R1 is methyl and the molar ratio of the aliphatic secondary amine alcohol to N-acetyl-2-propyn-1-amine is 1:1, when m is sequentially adjusted to m = 4 or 3 or 2 in sequence, the maximum excitation wavelength and the maximum emission wavelength of the obtained fatty amine type non-conventional fluorescent polymer are successively red-shifted.

[0029] Preferably, for Formula III, when the molar ratio of the aliphatic primary amine alcohol to ethylene glycol dipropargylate is 1:1, when m is sequentially adjusted to m = 2 or 3 or 4 or 6 in sequence, the maximum excitation wavelength and the maximum emission wavelength of the obtained fatty amine type non-conventional fluorescent polymer are successively red-shifted.

[0030] The present invention has the following beneficial effects:

[0031] (1) For the fatty amine type non-conventional fluorescent polymer of the present invention, by sequentially changing the length of the carbon chain of the secondary amine alcohol and the type of the substituent on the amino group in its reaction raw materials, the specific non-conventional fluorescent polymer undergoes sequential red-shift according to the adjustment sequence, realizing the change of the fluorescence color of the specific fatty amine type non-conventional fluorescent polymer from the blue light region to the red light region, and even to the near-infrared region in sequence;

[0032] (2) The method for adjusting the fluorescence color of the fatty amine type non-conventional fluorescent polymer of the present invention is simple, controllable and environmentally friendly;

[0033] (3) The research and development of the present invention will solve the core problem of the single luminescent color of fatty amine non - traditional luminescent materials, and provide key technical support for the following fields:

[0034] Multicolor anti - counterfeiting labels: High - security coding is achieved through the combination of polymers with different luminescent colors;

[0035] In - vivo multi - channel imaging: Fluorescent labels covering blue to red light can avoid the interference of autofluorescence of biological tissues;

[0036] Photodynamic therapy: Materials emitting in the red - light region have deeper tissue penetration ability, which can improve the treatment effect. Brief Description of the Drawings

[0037] Figure 1 : It is the emission diagram of LP - 1, LP - 2, LP - 3, LP - 4, LP - 5 and LP - 6 in Example 1 at their respective maximum excitation wavelengths.

[0038] Figure 2 : It is the emission spectrum diagram of LP - 7, LP - 8 and LP - 9 in Example 2 at their respective maximum excitation wavelengths.

[0039] Figure 3 : It is the emission spectrum diagram of BP - 1, BP - 2, BP - 3 and BP - 4 in Example 4 at their respective maximum excitation wavelengths.

[0040] Figure 4 : It is the visible - light and ultraviolet - light irradiation diagram of the mixture of LP - 1, LP - 2, LP - 3 and LP - 4 and silica powder in a mass ratio of 1:50 in Example 1.

[0041] Figure 5 : It is the application effect diagram of using the DMF solution formed by LP - 1, LP - 2, LP - 3 and LP - 4 in Example 1 as an anti - counterfeiting label.

[0042] Figure 6 : The fluorescence emission spectrum diagram of LP - 6 and the non - traditional linear fluorescent polymer obtained in Comparative Example 1.

[0043] Figure 7 : The fluorescence emission spectrum diagram of LP - 9 and the non - traditional linear fluorescent polymer obtained in Comparative Example 2. Detailed Embodiments

[0044] The present invention will be described in detail below with reference to the embodiments. However, it should be understood that the following embodiments are only illustrative examples of the implementation modes of the present invention, rather than limiting the scope of the present invention.

[0045] The activated alkyne monomers used in the following embodiments of the present invention can all be purchased on the market or easily synthesized. Among them, the activated alkyne monomers in the following embodiments of the present invention It can be synthesized according to the method reported in the reference (ACS Appl. Polym. Mater. 2024, 6, 4127 - 4137).

[0046] Example 1

[0047] Ethylene dipropargylate (0.222 g, 1 equiv) was successively mixed with N - benzylethanolamine (0.151 g, 1 equiv), 2 - (cyclohexylamino)ethanol (0.143 g, 1 equiv), 2 - methylaminoethanol (0.075 g, 1 equiv), 2 - (ethylamino)ethyl - 1 - ol (0.089 g, 1 equiv), 2 - (isopropylamino)ethanol (0.103 g, 1 equiv), 2 - (tert - butylamino)ethanol (0.117 g, 1 equiv) at 25 °C and stirred for reaction for 6 h. After the reaction, the four groups of reaction solutions were respectively subjected to sedimentation with n - hexane, filtration, and drying to obtain six non - traditional linear fluorescent polymers LP - 1, LP - 2, LP - 3, LP - 4, LP - 5, LP - 6 with different structures.

[0048] Through fluorescence spectroscopy tests, the maximum absorption peaks and emission peaks of LP - 1, LP - 2, LP - 3, LP - 4, LP - 5, LP - 6 in the solid state showed obvious red - shifts in turn. The maximum excitation wavelengths of LP - 1, LP - 2, LP - 3, LP - 4, LP - 5, LP - 6 in the solid state were 450 nm, 458 nm, 468 nm, 475 nm, 496 nm, 550 nm respectively, and the maximum emission wavelengths were 488 nm, 502 nm, 511 nm, 530 nm, 548 nm, 592 nm respectively, corresponding to blue light, cyan light, green light, yellow light, orange light, and red light (as shown in the attached instructions Figure 1 ), indicating that this method can regulate the emission color of the aliphatic amine - type non - traditional fluorescent polymer by adjusting the substituents on the amino group of the secondary amino alcohol monomer, making the emission color of the obtained aliphatic amine - type non - traditional linear fluorescent polymer gradually change from the blue - light region to the red - light region. Electron cloud density: phenyl < cyclohexyl < methyl < ethyl < isopropyl < tert - butyl.

[0049] The chemical formulas involved in the above reaction are as follows:

[0050]

[0051] Example 2

[0052] Ethylene glycol dipropargylate (0.222 g, 1 equiv) was successively mixed with 4-methylamino-1-butanol (0.117 g, 1 equiv), 3-(methylamino)-1-propanol (0.089 g, 1 equiv), and 2-methylaminoethanol (0.075 g, 1 equiv), and stirred at 25 °C for 6 h. After the reaction, the three groups of reaction solutions were sedimented with n-hexane to obtain three groups of non-traditional linear fluorescent polymers LP-7 (m = 4), LP-8 (m = 3), and LP-9 (m = 2) with different structures. Through fluorescence spectroscopy testing, the maximum absorption peaks and emission peaks of LP-7, LP-8, and LP-9 in the solid state showed obvious red shifts in turn. The maximum excitation wavelengths of LP-7, LP-8, and LP-9 in the solid state were 468, 579, and 588 nm, respectively, and the maximum emission wavelengths were 515, 619, and 628 nm, respectively, corresponding to cyan, red, and red light materials (as shown in the attached Figure 2 specification), indicating that this method can regulate the emission color of aliphatic amine-type non-traditional fluorescent polymers by adjusting the main chain structure of secondary amino alcohol monomers, making the emission color of the obtained aliphatic amine-type non-traditional linear fluorescent polymers gradually change from the blue light region to the red light region. The chemical formulas involved in the above reactions are as follows:

[0053]

[0054] Example 3

[0055] Ethylenediacetamide dipropargylate (0.220 g, 1 equiv) was successively mixed with 4-ethylamino-1-butanol (0.117 g, 1 equiv), 2-methylaminoethanol (0.075 g, 1 equiv), and 3-(methylamino)-1-propanol (0.089 g, 1 equiv), and stirred at 25 °C for 6 h. After the reaction, the three groups of reaction solutions were sedimented with n-hexane, filtered, and dried to obtain four groups of non-traditional linear fluorescent polymers LP-10, LP-11, and LP-12. Through fluorescence spectroscopy testing, the maximum absorption peaks and emission peaks of LP-10, LP-11, and LP-12 in the solid state showed obvious red shifts in turn. The maximum excitation wavelengths of LP-10, LP-11, and LP-12 in the solid state were 478, 579, and 610 nm, respectively, and the maximum emission wavelengths were 532, 642, and 674 nm, respectively, corresponding to green, red, and red light materials (as shown in the attached Figure 3 specification), indicating that this method can regulate the emission color of aliphatic amine-type non-traditional fluorescent polymers by adjusting the main chain structure of secondary amino alcohol monomers, making the emission color of the obtained aliphatic amine-type non-traditional linear fluorescent polymers gradually change from the blue light region to the red light region. The chemical formulas involved in the above reactions are as follows:

[0056] Example 4

[0057] Ethylene glycol dipropargylate (0.222 g, 1 equiv) was successively mixed and stirred with ethanolamine (0.061 g, 1 equiv), 3-amino-1-propanol (0.075 g, 1 equiv), 4-amino-1-butanol (0.089 g, 1 equiv), and 6-amino-1-hexanol (0.0117 g, 1 equiv) at 30 °C for 12 h. After the reaction, the four groups of reaction solutions were successively subjected to sedimentation with n-hexane, filtration, and drying to obtain three groups of non-traditional linear fluorescent polymers BP-1 (m = 2), BP-2 (m = 3), BP-3 (m = 4), and BP-4 (m = 6). Through fluorescence spectroscopy tests, the maximum absorption peaks and emission peaks of BP-1, BP-2, BP-3, and BP-4 in the solid state showed obvious red shifts in sequence. The maximum excitation wavelengths of BP-1, BP-2, BP-3, and BP-4 in the solid state were 480, 462, 438, and 433 nm, respectively, and the maximum emission wavelengths were 542, 522, 498, and 480 nm, respectively, corresponding to orange light, green light, cyan light, and blue-green light materials (as shown in the attached Figure 4 specification), indicating that this method can regulate the emission color of fatty amine-type non-traditional fluorescent polymers by adjusting the main chain structure of primary amine alcohol monomers, enabling the emission color of the obtained fatty amine-type non-traditional linear fluorescent polymers to gradually change from the blue light region to the red light region in sequence. The chemical formulas involved in the above reactions are as follows:

[0058]

[0059] Comparative Example 1 was the same as Example 1, except that R1 in Comparative Example 1 was a n-butyl group. Although the electron cloud density of the n-butyl group is smaller than that of the isopropyl group, the maximum excitation wavelength of the fluorescent polymer obtained in Comparative Example 1 was 504 nm, and the maximum emission wavelength was 557 nm. The emission spectrum diagram of the fluorescent polymer obtained in Comparative Example 1 is as shown in the attached Figure 6 specification. The reaction process involved in Comparative Example 1 is as follows:

[0060]

[0061] Comparative Example 2 was the same as Example 2, except that m in Comparative Example 2 was 6. The maximum excitation wavelength of the fluorescent polymer obtained in Comparative Example 2 was 582 nm, and the maximum emission wavelength was 609 nm. The emission spectrum diagram of the fluorescent polymer obtained in Comparative Example 2 is as shown in the attached Figure 7 specification. The reaction process involved in Comparative Example 2 is as follows:

[0062]

[0063] Inspired by the above-described ideal embodiments of the present invention, through the above description, relevant staff can make various changes and modifications completely within the scope without departing from the technical idea of the present invention. The technical scope of the present invention is not limited to the content in the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A method for sequentially red-shifting the emission wavelength of a fatty amine-based non-conventional fluorescent polymer, characterized in that, The fatty amine-based non-conventional fluorescent polymer includes the following general structural formula: Formula I, Formula II, Formula III, The above-mentioned fatty amine-based non-conventional fluorescent polymer is a product obtained by the room-temperature click reaction of the hydroxyl group of aliphatic primary amine alcohol or aliphatic secondary amine alcohol with the alkynyl group of ethylene glycol dipropargylate or dipropargyl acetamide. The value of n is determined by the raw material dosage and reaction conditions in the click reaction. In the above general structural formula, the value range of m is 2-6, m is an integer, and R1 includes straight-chain alkyl, cycloalkyl or aryl; By sequentially changing the value of m or the type of R1 substituent, the maximum absorption peak and emission peak of the above-mentioned fatty amine-based non-conventional fluorescent polymer are sequentially redshifted.

2. A method for sequentially red-shifting the emission wavelength of a fatty amine-based non-conventional fluorescent polymer according to claim 1, characterized in that The aliphatic secondary amine alcohol includes the following structural formula: R1 in the above structural formula includes straight-chain alkyl, cycloalkyl or aryl; the aliphatic secondary amine alcohol is a straight-chain secondary amine alcohol, and the value range of m is 2-6, m is an integer.

3. A method for sequentially red-shifting the emission wavelength of a fatty amine-based non-conventional fluorescent polymer according to claim 2, characterized in that R1 includes one of phenyl, cyclohexyl, methyl, ethyl, isopropyl, and tert-butyl.

4. A method for sequentially red-shifting the emission wavelength of a fatty amine-based non-conventional fluorescent polymer according to claim 1, characterized in that, The aliphatic primary amine alcohol includes the following structural formula: In the above structural formula, the value range of m is 2-6, m is an integer.

5. A method for sequentially red-shifting the emission wavelength of a fatty amine-based non-conventional fluorescent polymer according to claim 1, characterized in that, For Formula I, when m = 2 and the molar ratio of aliphatic secondary amine alcohol to ethylene glycol dipropargylate is 1:1, when R1 is sequentially adjusted to phenyl, cyclohexyl, methyl, ethyl, isopropyl or tert-butyl in order, the maximum excitation wavelength and maximum emission wavelength of the obtained fatty amine-based non-conventional fluorescent polymer are sequentially redshifted.

6. A method for sequentially red-shifting the emission wavelength of a fatty amine-based non-conventional fluorescent polymer according to claim 1, characterized in that For Formula II, when R1 is methyl and the molar ratio of aliphatic secondary amine alcohol to dipropargyl acetamide is 1:1, when m is sequentially adjusted to m = 4 or 3 or 2 in order, the maximum excitation wavelength and maximum emission wavelength of the obtained fatty amine-based non-conventional fluorescent polymer are sequentially redshifted.

7. A method for sequentially red-shifting the emission wavelength of a fatty amine-based non-conventional fluorescent polymer according to claim 1, characterized in that For Formula III, when the molar ratio of aliphatic primary amine alcohol to ethylene glycol dipropargylate is 1:1, when m is sequentially adjusted to m = 2 or 3 or 4 or 6 in order, the maximum excitation wavelength and maximum emission wavelength of the obtained fatty amine-based non-conventional fluorescent polymer are sequentially redshifted.

8. An anti-counterfeiting label, characterized in that, A method for sequentially redshift the emission wavelength of a fatty amine-based non-conventional fluorescent polymer as claimed in any one of claims 1-8 is utilized.

9. A fluorescence sensor, characterized in that, A method for sequentially redshift the emission wavelength of a fatty amine-based non-conventional fluorescent polymer as claimed in any one of claims 1-8 is utilized.

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