Functionalized polysiloxane with blue-green atypical fluorescence as well as preparation method and application thereof

Abstract

The invention discloses functionalized polysiloxane with blue-green atypical fluorescence as well as a preparation method and application thereof, and relates to the technical field of synthesis and application of siloxane polymers. Epoxy polysiloxane and a sulfydryl-containing furyl compound are adopted as reaction raw materials, and furyl polysiloxane with beta-hydroxyl is prepared on the basis of a sulfydryl-epoxy click chemical reaction. The space conjugation degree is increased by utilizing the hydrogen-bond interaction between beta-hydroxyl and furyl generated by the reaction, so that blue-green atypical fluorescence is emitted. The method has the advantages of simple process, quick reaction, high reaction conversion rate, high selectivity and the like, the obtained functionalized polysiloxane emits blue-green fluorescence under the irradiation of an ultraviolet lamp, and the light-emitting wave band of the polysiloxane with atypical fluorescence is effectively expanded. In addition, the atypical fluorescence can be enhanced by trifluralin, and pesticide detection is realized. The method has a good application prospect in the fields of preparation of organosilicon atypical fluorescent materials, sensor detection and the like.

Description

Technical Field

[0001] The invention relates to the technical field of synthesis and application of siloxane polymers, and in particular to a functionalized polysiloxane with blue-green atypical fluorescence and a preparation method and application thereof. Background Art

[0002] With the increasing demand for organosilicon materials in emerging fields such as artificial intelligence, new energy and biomedicine, how to effectively utilize existing organic chemical reactions, develop new methods for organosilicon synthesis, and prepare organosilicon materials with new structures and functions has become an important research direction in the organosilicon field. Among the many new functional organosilicon materials, organosilicon materials with atypical fluorescent properties have broad application prospects in the fields of sensors, bioimaging and lighting devices due to their good biocompatibility, flexibility, environmental friendliness and excellent luminescence properties.

[0003] At present, the fluorescence emission of silicone materials with atypical fluorescence properties is mainly concentrated in the blue light region, while the requirements for fluorescent materials in practical applications are rich and diverse. Blue fluorescence cannot meet the needs of many specific scenarios, which to a certain extent restricts the application of atypical fluorescent silicone materials in a wider range of fields. In the prior art, CN117700750A discloses a method for preparing a functionalized polysiloxane with atypical fluorescence. Among them, epoxy polysiloxane and thiol compound are used as raw materials, and under the action of a catalyst, a thiol-epoxy click chemical reaction is carried out to obtain a functionalized polysiloxane with atypical fluorescence. However, the fluorescence emission of the obtained functionalized polysiloxane is still concentrated in the blue region.

[0004] Trifluralin, chemical name is 2,6-dinitro-N,N-dipropyl-4-trifluoromethylaniline, chemical formula is C 13 H 16 F3N3O4. It is an orange-yellow crystalline powder, insoluble in water, but soluble in most organic solvents. It is a selective pre-emergence dinitroaniline herbicide widely used in crop planting, and is used to prevent fungal diseases in shrimp and crab seedling and breeding processes. Fluoralin pesticides can induce kidney and bladder tumors when inhaled by humans, and large doses of ingestion can cause respiratory failure. Due to its long half-life, it has potential effects on microorganisms and nitrogen cycles in the soil. At present, chromatography and photometry are mainly used to detect fluoralin pesticides, but the chromatography method has a long detection cycle and a small processing volume, and the photometry method has high cost and high environmental requirements. The fluorescence method has the advantages of excellent sensitivity, simple operation, and a low detection limit.

[0005] Therefore, it is necessary to prepare a functionalized polysiloxane with blue-green atypical fluorescence, red-shift the atypical fluorescence emission of silicone materials to improve the luminescence efficiency of silicone materials, and enable them to still exhibit good luminescence performance under smaller excitation energy, thereby broadening their application in pesticide detection. Summary of the invention

[0006] In view of the above-mentioned prior art, the purpose of the present invention is to provide a functionalized polysiloxane with blue-green atypical fluorescence and its preparation method and application. The present invention adopts epoxy polysiloxane and thiol-containing furanyl compound as reaction raw materials, and prepares furanyl polysiloxane with β-hydroxyl based on thiol-epoxy click chemistry reaction. The hydrogen bonding between the β-hydroxyl and furanyl generated by the reaction increases the degree of spatial conjugation, so that blue-green atypical fluorescence can be emitted. The present invention has the advantages of simple process, fast reaction, high reaction conversion rate, high selectivity, etc. The obtained functionalized polysiloxane emits blue-green fluorescence under ultraviolet light irradiation, effectively expanding the luminescence band of polysiloxane with atypical fluorescence. In addition, the atypical fluorescence can be enhanced by trifluralin to detect pesticides. The method has good application prospects in the fields of preparing organosilicon atypical fluorescent materials, sensor detection, etc.

[0007] To achieve the above object, the present invention adopts the following technical solution:

[0008] In a first aspect of the present invention, a functionalized polysiloxane having blue-green atypical fluorescence is provided, wherein the structural formula of the functionalized polysiloxane is as shown in Formula I or Formula II.

[0009]

[0010] In Formula I and Formula II, n is an integer greater than or equal to 2, m is an integer greater than or equal to 1, R1, R2, R4, R5, and R6 are selected from C1-C18 straight chain or branched saturated or unsaturated hydrocarbon groups, or hydrocarbon groups with heteroatoms such as O, S, and N, or cycloalkanes or aromatic hydrocarbons, and R1, R2, R4, R5, and R6 are the same or different; R3 and R7 are C1-C18 straight chain or branched saturated or unsaturated hydrocarbon groups, or hydrocarbon groups with heteroatoms such as O and S or cycloalkyl and benzene rings; R8 and R9 are selected from furanyl-containing compounds.

[0011] Preferably, the structural formula of the functionalized polysiloxane is as shown in Formula III or Formula IV,

[0012]

[0013]

[0014] The second aspect of the present invention provides a method for preparing a functionalized polysiloxane having blue-green atypical fluorescence, comprising the following steps:

[0015] After epoxy polysiloxane, a furanyl-containing mercapto compound and a catalyst are mixed, the mixture is subjected to mercapto-epoxy reaction, and separated and purified to obtain a functionalized polysiloxane with blue-green atypical fluorescence.

[0016] Preferably, the epoxy polysiloxane is an epoxy-terminated polysiloxane or a polysiloxane having at least one epoxy group in the side chain.

[0017] Further preferably, the epoxy-terminated polysiloxane has a structural formula as shown in Formula V, and its relative molecular mass is 500-10000 g / mol; the structural formula of the polysiloxane containing at least one epoxy group in the side chain is shown in Formula IV, and its relative molecular mass is 500-10000 g / mol;

[0018]

[0019] In Formula V and Formula VI, n and m are both integers greater than or equal to 1, and R1, R2, R4, R5, and R6 are selected from C1-C 18 A straight-chain saturated or unsaturated hydrocarbon group, or a hydrocarbon group with heteroatoms such as O, S, N, or a cycloalkane or aromatic hydrocarbon, R1, R2, R4, R5, R6 are the same or different; R3, R7 are C1-C 18 A straight-chain or branched saturated or unsaturated hydrocarbon group, or a hydrocarbon group with an O, S heteroatom or a cycloalkyl or benzene ring.

[0020] More preferably, the relative molecular mass of the epoxy polysiloxane in Formula V and Formula VI is 1000-50000 g / mol.

[0021] Preferably, the molar ratio of the epoxy group in the epoxy polysiloxane to the mercapto group in the furyl group-containing mercapto compound is 1:(1-5).

[0022] More preferably, the molar ratio of the epoxy group in the epoxy polysiloxane to the mercapto group in the furyl group-containing mercapto compound is 1:(3-5).

[0023] Preferably, the catalyst is tetramethylammonium hydroxide, lithium hydroxide, tetra-n-butylammonium fluoride, 1,8-diazabicyclo[5.4.0]undec-7-ene or triethylamine.

[0024] Preferably, the amount of the catalyst used is 1-25 mol% of the molar amount of epoxy groups in the epoxy polysiloxane.

[0025] Preferably, in the thiol-epoxy reaction, the reaction temperature is 20-80° C. and the reaction time is 0.5-48 h.

[0026] Preferably, the thiol-epoxy reaction can be carried out in an organic solvent or in the absence of a solvent.

[0027] Further preferably, when the mercapto-epoxy reaction is carried out in an organic solvent, the organic solvent is tetrahydrofuran, dichloromethane or toluene, and the solid-liquid ratio of epoxysiloxane to the organic solvent is 1 g: (1-100) mL.

[0028] The third aspect of the present invention provides the use of functionalized polysiloxane with blue-green atypical fluorescence in pesticide detection.

[0029] Preferably, the pesticide is trifluralin.

[0030] Beneficial effects of the present invention:

[0031] The present invention uses epoxy polysiloxane and a thiol-containing furanyl compound as reaction raw materials, and prepares a furanyl polysiloxane having a β-hydroxyl group based on a thiol-epoxy click chemistry reaction. The hydrogen bonding between the β-hydroxyl group and the furanyl group generated by the reaction increases the degree of spatial conjugation, thereby emitting a blue-green atypical fluorescence.

[0032] The specific reaction principle is: epoxy polysiloxane and thiol-containing furanyl compounds are used as reaction materials. After the thiol group reacts with the base, the thiol anion forms a thiol anion. The thiol anion acts as a nucleophile to attack the carbon atom with small steric hindrance on the epoxy group. After the epoxy ring is opened, a thiolate anion intermediate is formed. After the hydrogen ion in the reaction system is captured, the final product containing β-hydroxyl is formed. The furan oxygen atom and the β-hydroxyl group form a polycyclic ring under the action of hydrogen bonding. Due to the coordination effect of S→Si, the aggregation of electron-rich groups in the molecules (O…O) and the spatial conjugation of the eight-membered ring are increased, thereby enhancing the atypical fluorescence of the functionalized polysiloxane and emitting blue-green fluorescence.

[0033] The present invention provides a new, simple and efficient way to design and prepare atypical fluorescent materials with longer emission wavelengths. The prepared functionalized polysiloxane emits blue-green fluorescence under ultraviolet light, effectively expanding the luminescent band of polysiloxane with atypical fluorescence. In addition, trifluralin and electron-rich groups (S or N atoms) transfer electrons or energy, and this interaction can enhance S→Si coordination, resulting in enhanced fluorescence intensity, thereby achieving detection of trifluralin. It can be seen that the blue-green atypical fluorescence prepared by the present invention can be enhanced by trifluralin, thereby achieving detection of trifluralin pesticides. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 : H-NMR spectrum of the functionalized polysiloxane with blue-green atypical fluorescence obtained in Example 1;

[0035] Figure 2: Fluorescence emission spectra of functionalized polysiloxane solutions of different concentrations in Example 1;

[0036] Figure 3 : Luminescence effect diagram of functionalized polysiloxane solutions of different concentrations under ultraviolet light in Example 1;

[0037] Figure 4 : H-NMR spectrum of the functionalized polysiloxane with blue-green atypical fluorescence obtained in Example 2;

[0038] Figure 5 : Fluorescence emission spectra of functionalized polysiloxane solutions of different concentrations in Example 2;

[0039] Figure 6 : Luminescence effect diagram of functionalized polysiloxane solutions of different concentrations under ultraviolet light in Example 2;

[0040] Figure 7 : Fluorescence emission spectra of the functionalized polysiloxane solution before and after adding trifluralin in Experimental Example 1. DETAILED DESCRIPTION

[0041] It should be noted that the following detailed descriptions are illustrative and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present application belongs.

[0042] In order to enable those skilled in the art to more clearly understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below in conjunction with specific embodiments.

[0043] The experimental materials used in the embodiments of the present invention are all conventional experimental materials in the art and can be purchased through commercial channels.

[0044] Example 1: Preparation of functionalized polysiloxane with blue-green atypical fluorescence

[0045] Using M n =2600g / mol of terminal epoxy silicone oil and furfuryl mercaptan are used as reaction raw materials, wherein the molar amount of epoxy groups in the terminal epoxy silicone oil is 0.0015mol, and anhydrous lithium hydroxide is used as a catalyst.

[0046] 1.95 g of epoxy-terminated silicone oil, 0.3424 g of furfuryl mercaptan and 0.012 g of anhydrous lithium hydroxide were mixed, and the mixture was stirred at 40° C. for 24 h for a thiol-epoxy reaction. After the reaction was completed, a crude product was obtained. Ethanol and water were mixed in a volume ratio of 1:1 to obtain a mixed solution. The mixed solution was added to the crude product for washing and centrifugation. The operation was repeated 4-5 times to remove excess n-butyl mercaptan and residual lithium hydroxide catalyst. The organic phase was then separated and dried to obtain 2.1778 g of a brown transparent viscous liquid, which was a functionalized polysiloxane with blue-green atypical fluorescence, and the yield was 95%.

[0047] The structure of the functionalized polysiloxane prepared by the present invention is as follows:

[0048]

[0049] The functionalized polysiloxane prepared in this example was characterized by the following structure: Figure 1 shown.

[0050] After the thiol-epoxy reaction, the characteristic peak of epoxy in the product of Example 1 disappeared, and the single proton peak of β-hydroxy carbon appeared at 3.77 ppm and the characteristic peaks of furan appeared at 6.13, 6.23, and 7.28 ppm, indicating that the structure of the target product was correct.

[0051] In addition, ethanol was used as a solvent to prepare functionalized polysiloxane solutions of different concentrations (0.1 mg / mL, 1 mg / mL, 2 mg / mL and 5 mg / mL), and the fluorescence emission spectra of the functionalized polysiloxane solutions of different concentrations were detected. The results are as follows: Figure 2 At the same time, the functionalized polysiloxane solutions of different concentrations were irradiated under ultraviolet light to observe the fluorescence phenomenon. The results are as follows Figure 3 shown.

[0052] Depend on Figure 2 It can be seen that when the concentration of the functionalized polysiloxane solution is 5 mg / mL, the maximum emission wavelength is 502 nm. Figure 3 It can be seen that the functionalized polysiloxane solution emits blue-green light under ultraviolet light.

[0053] Example 2: Preparation of functionalized polysiloxane with blue-green atypical fluorescence

[0054] Side chain end-containing epoxy silicone oil and furfuryl mercaptan are used as reaction raw materials, wherein the epoxy molar content of the side chain end-containing epoxy silicone oil is 13%, and the epoxy molar amount is 0.0015 mol. Anhydrous lithium hydroxide is used as a catalyst.

[0055] 0.5 g of side chain epoxy-terminated silicone oil, 0.3425 g of furfuryl mercaptan and 0.012 g of anhydrous lithium hydroxide were mixed, and the mixture was stirred at 50° C. for 24 h for a thiol-epoxy reaction. After the reaction was completed, a crude product was obtained. Ethanol and water were mixed in a volume ratio of 1:1 to obtain a mixed solution. The mixed solution was added to the crude product for washing and centrifugation. The operation was repeated 4-5 times to remove excess n-butyl mercaptan and residual lithium hydroxide catalyst. The organic phase was then separated and dried to obtain 0.8088 g of a brown transparent viscous liquid, which was a functionalized polysiloxane with blue-green atypical fluorescence, and the yield was 96%.

[0056] The structure of the functionalized polysiloxane prepared by the present invention is as follows:

[0057]

[0058] The functionalized polysiloxane prepared in this example was characterized by the following structure: Figure 4 shown.

[0059] After the thiol-epoxy reaction, the characteristic peak of epoxy in the product of Example 2 disappeared, and the single proton peak of β-hydroxy carbon appeared at 3.77 ppm and the characteristic peaks of furan appeared at 6.12, 6.22, and 7.28 ppm, indicating that the structure of the target product was correct.

[0060] In addition, ethanol was used as a solvent to prepare functionalized polysiloxane solutions of different concentrations (0.1 mg / mL, 1 mg / mL, 2 mg / mL and 5 mg / mL), and the fluorescence emission spectra of the functionalized polysiloxane solutions of different concentrations were detected. The results are as follows: Figure 5 At the same time, the functionalized polysiloxane solutions of different concentrations were irradiated under ultraviolet light to observe the fluorescence phenomenon. The results are as follows Figure 6 shown.

[0061] Depend on Figure 5 It can be seen that when the concentration of the functionalized polysiloxane solution is 5 mg / mL, the maximum emission wavelength is 502 nm. Figure 6 It can be seen that the functionalized polysiloxane solution emits blue-green light under ultraviolet light.

[0062] Test Example 1: Trifluralin Detection

[0063] The functionalized polysiloxane with atypical blue-green fluorescence obtained in Example 1 was mixed with ethanol to obtain a functionalized polysiloxane solution with a concentration of 5 mg / mL. A 0.005 mg / ml trifluralin solution and a 5 mg / mL functionalized polysiloxane solution were mixed at a volume ratio of 2:1 to obtain a mixed solution as the test group. A blank control group was also set up, which contained only a 5 mg / mL functionalized polysiloxane solution. The fluorescence intensity of the test group and the blank control group was quickly recorded using a fluorescence spectrophotometer. The results are shown in FIG. Figure 7 shown.

[0064] Depend on Figure 7 It can be seen that after the addition of fluroxypyridine, the fluorescence intensity of the functionalized polysiloxane solution increased by about 2.6 times, and the maximum emission wavelength blue-shifted from 502 nm to about 450 nm, indicating that sample A has a significant responsiveness to fluroxypyridine and can be used for the detection of fluroxypyridine.

[0065] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A functionalized polysiloxane having a blue-green atypical fluorescence, characterized in that: The structural formula of the functionalized polysiloxane is shown in Formula I or Formula II, In Formula I and Formula II, n is an integer greater than or equal to 2, m is an integer greater than or equal to 1, R1, R2, R4, R5, and R6 are selected from C1-C18 straight chain or branched saturated or unsaturated hydrocarbon groups, or hydrocarbon groups with heteroatoms such as O, S, and N, or cycloalkanes or aromatic hydrocarbons, and R1, R2, R4, R5, and R6 are the same or different; R3 and R7 are C1-C18 straight chain or branched saturated or unsaturated hydrocarbon groups, or hydrocarbon groups with heteroatoms such as O and S or cycloalkyl and benzene rings; R8 and R9 are selected from furanyl-containing compounds.

2. The functionalized polysiloxane having blue-green atypical fluorescence according to claim 1, characterized in that: The structural formula of the functionalized polysiloxane is shown in Formula III or Formula IV, 3. The method for preparing the functionalized polysiloxane having blue-green atypical fluorescence according to claim 1 or 2, characterized in that: The following steps are involved: After epoxy polysiloxane, a furanyl-containing mercapto compound and a catalyst are mixed, the mixture is subjected to mercapto-epoxy reaction, and separated and purified to obtain a functionalized polysiloxane with blue-green atypical fluorescence.

4. The method for preparing the functionalized polysiloxane having blue-green atypical fluorescence according to claim 3, characterized in that: The epoxy polysiloxane is an epoxy-terminated polysiloxane or a polysiloxane having at least one epoxy group in a side chain.

5. The method for preparing the functionalized polysiloxane having blue-green atypical fluorescence according to claim 4, characterized in that: The structural formula of the epoxy-terminated polysiloxane is shown in Formula V, and its relative molecular mass is 500-10000 g / mol; the structural formula of the polysiloxane containing at least one epoxy group in the side chain is shown in Formula IV, and its relative molecular mass is 500-10000 g / mol; In Formula V and Formula VI, n and m are both integers greater than or equal to 1, and R1, R2, R4, R5, and R6 are selected from C1-C 18 A straight-chain saturated or unsaturated hydrocarbon group, or a hydrocarbon group with heteroatoms such as O, S, N, or a cycloalkane or aromatic hydrocarbon, R1, R2, R4, R5, R6 are the same or different; R3, R7 are C1-C 18 A straight-chain or branched saturated or unsaturated hydrocarbon group, or a hydrocarbon group with an O, S heteroatom or a cycloalkyl or benzene ring.

6. The functionalized polysiloxane having blue-green atypical fluorescence according to claim 3, characterized in that: The molar ratio of the epoxy group in the epoxy polysiloxane to the mercapto group in the furyl group-containing mercapto compound is 1:(1-5).

7. The functionalized polysiloxane having blue-green atypical fluorescence according to claim 3, characterized in that: The catalyst is tetramethylammonium hydroxide, lithium hydroxide, tetra-n-butylammonium fluoride, 1,8-diazabicyclo[5.4.0]undec-7-ene or triethylamine.

8. The functionalized polysiloxane having blue-green atypical fluorescence according to claim 3, characterized in that: The amount of the catalyst used is 1-25 mol% of the molar amount of epoxy groups in the epoxy polysiloxane.

9. The method for preparing the functionalized polysiloxane having blue-green atypical fluorescence according to claim 3, characterized in that: In the thiol-epoxy reaction, the reaction temperature is 20-80°C and the reaction time is 0.5-48h.

10. Use of the functionalized polysiloxane having blue-green atypical fluorescence according to claim 1 or 2 in pesticide detection.

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