A triphenylamine derivative and its preparation method, pH-responsive color-changing fiber and its preparation method
By synthesizing triphenylamine derivatives and mixing them with cellulose to prepare pH-responsive color-changing fibers, the problem of monitoring solution pH changes in vitro was solved, and visual monitoring of acid solution concentration and multiple uses were achieved.
Patent Information
- Application Number
- CN202410779602.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2024-06-17
- Publication Date
- 2025-09-16
- Estimated Expiration
- 2044-06-17
AI Technical Summary
The prior art lacks effective methods for monitoring changes in solution pH in vitro, especially visualization methods through color changes.
Triphenylamine derivatives were designed and synthesized, and aggregation-induced emission molecules with donor-acceptor structures were generated by Suzuki reaction and reaction with different pyridine groups. These molecules were then mixed with cellulose and prepared into pH-responsive color-changing fibers by wet spinning.
It realizes an intuitive response to the pH change of the acid solution, can monitor the concentration change of the acid solution, has thermal stability, and can be recycled multiple times.
Smart Images
Figure CN118791473B_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the synthesis and application of triphenylamine derivatives, in particular to a triphenylamine derivative and a preparation method thereof, a pH-responsive color-changing fiber and a preparation method thereof. Background Art
[0002] pH monitoring plays an indispensable role in protecting environmental safety, maintaining ecological balance, and safeguarding human health, especially in environmental monitoring, water treatment, biological health, and industrial production. Observing color changes is an effective visual monitoring method for pH response.
[0003] Currently, aggregation-induced emission molecules are widely used in various fields, such as bioimaging, optoelectronic devices, and smart responsive materials, due to their unique photophysical properties and rapid response. However, there are no reports on the pH response of aggregation-induced emission molecules in solvents in vitro. Based on this, the present application is filed. Summary of the Invention
[0004] The purpose of the present invention is to overcome the defects of the prior art and provide a triphenylamine derivative and a preparation method thereof, a pH-responsive color-changing fiber and a preparation method thereof. The present invention utilizes the commonly used skeleton triphenylamine to design and synthesize molecules with pH-responsive function, and utilizes the advantages of fast production and high utilization rate of mature wet spinning technology in the textile field to prepare triphenylamine aggregation-inducing molecules and cellulose into fibers with pH-responsive intelligent function.
[0005] The present invention provides the following technical solutions:
[0006] The present invention provides a triphenylamine derivative comprising the following structure:
[0007]
[0008] The present invention also provides a method for preparing the above-mentioned triphenylamine derivative, comprising the following steps:
[0009] S1, [4-[bis(4-methoxyphenyl)amino]phenyl]boronic acid and 4,7-dibromo-2,1,3-benzothiadiazole undergo Suzuki reaction to synthesize an intermediate molecule;
[0010] S2 and the intermediate molecule react with 4-boronic acid pyridine, 4-vinyl pyridine, and 4-ethynyl pyridine, respectively, to obtain triphenylamine derivative (1), triphenylamine derivative (2), and triphenylamine derivative (3);
[0011] The structural formula of the intermediate molecule is:
[0012]
[0013] The present invention first synthesizes an intermediate molecule through Suzuki reaction, and then the intermediate molecule reacts with different pyridine reactants to generate corresponding triphenylamine derivatives. The triphenylamine derivatives have a pyridine group and a donor-acceptor (DA) structure.
[0014] Furthermore, step S1 includes mixing [4-[bis(4-methoxyphenyl)amino]phenyl]boric acid, 4,7-dibromo-2,1,3-benzothiadiazole, potassium carbonate and tetrakis(triphenylphosphine)palladium, adding a reaction solvent under an inert gas environment for sufficient reaction, and obtaining an intermediate molecule through post-treatment.
[0015] The reaction solvent is tetrahydrofuran and water, and the volume ratio of tetrahydrofuran to water is (3-4):1.
[0016] The molar ratio of [4-[bis(4-methoxyphenyl)amino]phenyl]boric acid, 4,7-dibromo-2,1,3-benzothiadiazole, potassium carbonate and tetrakis(triphenylphosphine)palladium is 1:(1-2):(5-7):(0.04-0.06).
[0017] Furthermore, the step S2 comprises: mixing the intermediate molecule, 4-pyridine borate, potassium carbonate and tetrakis(triphenylphosphine)palladium, adding a reaction solvent under an inert environment to fully react, and obtaining the triphenylamine derivative (1) through post-treatment.
[0018] The reaction solvent is tetrahydrofuran and water, and the volume ratio of tetrahydrofuran to water is (3-4):1.
[0019] The molar ratio of the intermediate molecule, 4-pyridine borate, potassium carbonate and tetrakis(triphenylphosphine)palladium is 1:(1.5-2):(5-7):(0.04-0.06).
[0020] Furthermore, the step S2 comprises: mixing the intermediate molecule, 4-vinylpyridine, palladium acetate and tri(o-methylphenyl)phosphine, adding a reaction solvent under an inert environment to fully react, and obtaining a triphenylamine derivative (2) through post-treatment.
[0021] The reaction solvent is triethylamine and N,N-dimethylformamide, and the volume ratio of triethylamine to N,N-dimethylformamide is 1:(0.5-1).
[0022] The molar ratio of the intermediate molecule, 4-vinylpyridine, palladium acetate and tri(o-methylphenyl)phosphine is 1:(1.5-2):(0.1-0.3):(0.2-0.3).
[0023] Furthermore, the step S2 comprises: mixing the intermediate molecule, 4-ethynylpyridine, cuprous iodide and tetrakis(triphenylphosphine)palladium, adding a reaction solvent under an inert environment to fully react, and obtaining a triphenylamine derivative (3) through post-treatment.
[0024] The reaction solvent is triethylamine.
[0025] The molar ratio of the intermediate molecule, 4-ethynylpyridine, cuprous iodide and tetrakis(triphenylphosphine)palladium is 1:(1-2):(0.3-0.5):(0.1-0.2).
[0026] After sufficient reaction in each of the above steps, the corresponding product can be obtained. Post-processing is required to extract the product for subsequent application. Post-processing includes conventional processing steps such as washing, drying, and purification.
[0027] The present invention also provides the use of the triphenylamine derivative in pH-responsive color change. The triphenylamine derivative designed and synthesized by the present invention exhibits aggregation-induced emission properties. The pyridine group carried by the triphenylamine derivative undergoes protonation in an acidic environment, causing a color change that can intuitively reflect the pH change of the solution. It can be applied in fields related to pH-responsive color change, such as monitoring changes in acid solution concentration.
[0028] The triphenylamine derivative provided by the present invention can be used directly, but for repeated use and cost savings, it can be prepared into pH-responsive color-changing fibers. Based on this, the present invention also provides a method for preparing pH-responsive color-changing fibers, comprising adding the triphenylamine derivative prepared above to a cellulose spinning solution and wet-spinning the fibers to produce pH-responsive color-changing fibers.
[0029] Furthermore, the solvent in the cellulose spinning solution is dimethyl sulfoxide and ionic liquid 1-butyl-3-methylimidazolium chloride, with a mass ratio of 1:(2-3), and the mass proportion of the triphenylamine derivative in the cellulose spinning solution is 0.1%-1%.
[0030] The present invention also provides pH-responsive color-changing fibers prepared by the above preparation method.
[0031] The present invention has the following beneficial effects:
[0032] 1. The triphenylamine derivative prepared by the present invention exhibits an aggregation-induced emission effect and can respond to pH changes in acid solutions by changing color, thus realizing the pH color change response of aggregation-induced emission molecules in in vitro solvents;
[0033] 2. The present invention mixes triphenylamine derivatives with cellulose and then prepares pH color-responsive fibers through wet spinning, which can also respond to changes in acid solution concentration;
[0034] 3. The pH color-changing response fiber prepared by the present invention has different response times to acid solutions of different concentrations and strengths. This characteristic can be used to predict the concentration range of a known acid solution;
[0035] 4. The pH color-changing responsive fiber prepared by the present invention has good thermal stability, can be restored to its original color after alkali treatment, and can be recycled multiple times. BRIEF DESCRIPTION OF THE DRAWINGS
[0036] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.
[0037] Figure 1 is a synthetic route diagram of the triphenylamine derivatives of the present invention;
[0038] Figure 2 is the hydrogen nuclear magnetic resonance spectrum of the intermediate molecule of the present invention;
[0039] Figure 3 The nuclear magnetic resonance characterization diagram of the triphenylamine derivative PS-1 prepared in Example 1 of the present invention (a is the hydrogen spectrum, b is the carbon spectrum);
[0040] Figure 4 The nuclear magnetic resonance characterization diagram of the triphenylamine derivative PS-2 prepared in Example 2 of the present invention (a is the hydrogen spectrum, b is the carbon spectrum);
[0041] Figure 5 The nuclear magnetic resonance characterization diagram of the triphenylamine derivative PS-3 prepared in Example 3 of the present invention (a is the hydrogen spectrum, b is the carbon spectrum);
[0042] Figure 6 Characterization of the aggregation-induced emission properties of PS-1, PS-2, and PS-3 prepared in accordance with the present invention;
[0043] Figure 7 The color change pictures of PS-1, PS-2, and PS-3 prepared in the examples of the present invention at 95% aggregation state in aqueous solvents with different pH values are shown;
[0044] Figure 8 The fluorescence spectra of PS-1, PS-2, and PS-3 prepared in the examples of the present invention in aqueous solutions with different pH values at 95% aggregation are shown;
[0045] Figure 9 These are pictures of different pH-responsive fibers prepared in Application Example 1 of the present invention;
[0046] Figure 10Electron micrographs of the surfaces of fibers with different pH responses in the present invention (a and e are control cellulose fibers, b and f are PS-1 fibers, e and g are PS-2 fibers, and d and h are PS-3 fibers);
[0047] Figure 11 Electron micrographs of cross sections of different pH-responsive fibers in the present invention (a and e are control cellulose fibers, b and f are PS-1 fibers, e and g are PS-2 fibers, and d and h are PS-3 fibers);
[0048] Figure 12 The fluorescence intensity at the peak of the different pH response fiber cycle test (0.5 M sodium hydroxide aqueous solution treatment) in the present invention;
[0049] Figure 13 The thermogravimetric test diagram of the fiber before and after pH cycle response in the present invention (where a is before response and b is after response);
[0050] Figure 14 These are electron microscope images of the fiber surface after pH cycle response in the present invention (where a and d are PS-1 fiber, b and e are PS-2 fiber, and c and f are PS-3 fiber)). DETAILED DESCRIPTION
[0051] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.
[0052] The present invention uses triphenylamine as a skeleton to synthesize and design an aggregation-induced luminescence molecule with pH response function. The synthesis route is shown in Figure 1 First, an intermediate molecule is synthesized through a Suzuki reaction, and the intermediate molecule then reacts with different pyridine reactants to generate the corresponding triphenylamine derivative. The triphenylamine derivative has a pyridine group and a donor-acceptor (DA) structure.
[0053] The target structure of the triphenylamine derivative is:
[0054]
[0055] The preparation method of the triphenylamine derivative of the above structure comprises the steps of:
[0056] S1, [4-[bis(4-methoxyphenyl)amino]phenyl]boronic acid and 4,7-dibromo-2,1,3-benzothiadiazole undergo Suzuki reaction to synthesize an intermediate molecule;
[0057] S2 and the intermediate molecule react with 4-boronic acid pyridine, 4-vinyl pyridine, and 4-ethynyl pyridine, respectively, to obtain triphenylamine derivative (1), triphenylamine derivative (2), and triphenylamine derivative (3).
[0058] The structural formula of the intermediate molecule is:
[0059]
[0060] The present invention is further described below with reference to specific examples. The reagents used in the following examples can all be purchased commercially.
[0061] Example 1:
[0062] The preparation process of the triphenylamine derivative in this embodiment is as follows:
[0063] 1. Synthesis of intermediate molecule: In a 150 mL two-necked round-bottom flask, [4-[bis(4-methoxyphenyl)amino]phenyl]boronic acid (250 mg, 0.71 mmol), 4,7-dibromo-2,1,3-benzothiadiazole (420 mg, 1.42 mmol), potassium carbonate (590 mg, 4.27 mmol), and tetrakis(triphenylphosphine)palladium (42 mg, 0.036 mmol) were added. The air in the round-bottom flask was removed by two cycles of vacuuming and nitrogen filling. Subsequently, tetrahydrofuran (60 mL) and water (20 mL) were added to the flask, and the mixture was refluxed at 66° C. under nitrogen atmosphere overnight. The reaction progress was monitored by thin layer chromatography (TLC).
[0064] After the reaction of the raw materials was complete, the mixture was extracted three times with dichloromethane and washed with water. The organic layer was separated and dried over anhydrous sodium sulfate. After evaporation of the solvent, the crude product was purified by silica gel column chromatography using petroleum ether / dichloromethane (2 / 1, V / V) as the eluent. The eluent containing the product was dried by spin drying to obtain a red powder of the intermediate molecule (271 mg, 73.9%). 1 HNMR (400MHz, Chloroform-d): δ7.88(d,J=7.6Hz,2H),7.76(s,2H),7.50(d,J=7.6Hz,2H),7.10(s,2H),6.87(d,J=8.0Hz,6H),3.83(s,6H).
[0065] 2. Synthesis of triphenylamine derivatives: In a 150 mL two-necked round-bottom flask, the intermediate molecule (200 mg, 0.375 mmol), 4-pyridinium borate (73.8 mg, 0.6 mmol), potassium carbonate (312 mg, 2.26 mmol), and tetrakis(triphenylphosphine)palladium (22 mg, 0.019 mmol) were added. The air in the round-bottom flask was removed by two cycles of vacuuming and nitrogen filling. Subsequently, tetrahydrofuran (60 mL) and water (20 mL) were added to the flask and refluxed overnight at 66°C under nitrogen protection. The reaction progress was monitored by thin layer chromatography (TLC).
[0066] After the reaction of the starting material was complete, the mixture was extracted three times with dichloromethane and washed with water. The organic layer was separated and dried over anhydrous sodium sulfate. After evaporation of the solvent, the crude product was purified by silica gel column chromatography using petroleum ether / dichloromethane (1 / 3, v / v) as the eluent. The eluent containing the product was dried by spin drying to obtain a red powder (150 mg, 73.6%), designated as the triphenylamine derivative PS-1. 1 H NMR (400MHz, Chloroform-d): δ8.78(d,J=5.4Hz,2H),8.12(d,J=5.8Hz,2H),7.94(d,J=7.6Hz,1H),7.85(d,J=8. 6Hz, 2H), 7.78 (d, J = 7.6Hz, 1H), 7.16 (d, J = 8.8Hz, 4H), 7.06 (d, J = 8.4Hz, 2H), 6.88 (d, J = 8.8Hz, 4H), 3.82 (s, 6H). 13 C NMR (101MHz, Chloroform-d): δ156.47,154.27,150.28,149.53,144.98,140.47, 135.11,130.06,129.16,128.98,128.31,127.36,126.58,123.61,114.96,55.66.
[0067] Example 2:
[0068] The preparation process of the triphenylamine derivative in this embodiment is as follows:
[0069] 1. Synthesis of intermediate molecule: In a 150 mL two-necked round-bottom flask, [4-[bis(4-methoxyphenyl)amino]phenyl]boronic acid (250 mg, 0.71 mmol), 4,7-dibromo-2,1,3-benzothiadiazole (420 mg, 1.42 mmol), potassium carbonate (590 mg, 4.27 mmol), and tetrakis(triphenylphosphine)palladium (42 mg, 0.036 mmol) were added. The air in the round-bottom flask was removed by two cycles of vacuuming and nitrogen filling. Subsequently, tetrahydrofuran (60 mL) and water (20 mL) were added to the flask, and the mixture was refluxed at 66° C. under nitrogen atmosphere overnight. The reaction progress was monitored by thin layer chromatography (TLC).
[0070] After the reaction of the raw materials was complete, the mixture was extracted three times with dichloromethane and washed with water. The organic layer was separated and dried over anhydrous sodium sulfate. After evaporation of the solvent, the crude product was purified by silica gel column chromatography using petroleum ether / dichloromethane (2 / 1, V / V) as the eluent. The eluent containing the product was dried by spin drying to obtain a red powder of the intermediate molecule (271 mg, 73.9%). 1 HNMR (400MHz, Chloroform-d): δ7.88(d,J=7.6Hz,2H),7.76(s,2H),7.50(d,J=7.6Hz,2H),7.10(s,2H),6.87(d,J=8.0Hz,6H),3.83(s,6H).
[0071] 2. Synthesis of triphenylamine derivatives: The intermediate molecule (200 mg, 0.375 mmol) and 4-vinylpyridine (60 mg, 0.57 mmol) were added to a 100 ml two-necked round-bottom flask. The air in the round-bottom flask was removed by two cycles of vacuum evacuation and nitrogen refilling. Palladium acetate (9 mg, 0.04 mmol) and tri(o-methylphenyl)phosphine) (24 mg, 0.08 mmol) were then dissolved in ultra-dry and degassed TEA / DMF (2 / 1, v / v) and stirred for 20 min. The degassed solution was poured into a 100 ml round-bottom flask and reacted overnight at 90°C under a nitrogen atmosphere.
[0072] The reaction progress was monitored by thin layer chromatography (TLC). After the reaction of the starting material was complete, the solvent was evaporated and the crude product was purified by silica gel column chromatography using ethyl acetate / petroleum ether (1 / 1, V / V) as eluent to obtain PS-2 as a red powder (150 mg, 71%), which was recorded as the triphenylamine derivative PS-2. 1HNMR (400MHz, Chloroform-d): δ8.65–8.59(m,2H),7.98(d,J=16.4Hz,1H),7.84(d,J=2.0Hz,1H),7.82–7.74(m,3H ),7.68(d,J=7.4Hz,1H),7.53–7.47(m,2H),7.19–7.11(m,4H),7.09–7.01(m,2H),6.91–6.83(m,4H),3.82(s,6H). 13 C NMR (101MHz, CDCl3): δ156.42,154.22,150.37,145.09,140.51,130.19,129.99,12 9.23,129.11,127.30,126.68,121.20,119.64,114.94,77.48,77.16,76.84,55.66.
[0073] Example 3:
[0074] The preparation process of the triphenylamine derivative in this embodiment is as follows:
[0075] 1. Synthesis of intermediate molecule: In a 150 mL two-necked round-bottom flask, [4-[bis(4-methoxyphenyl)amino]phenyl]boronic acid (250 mg, 0.71 mmol), 4,7-dibromo-2,1,3-benzothiadiazole (420 mg, 1.42 mmol), potassium carbonate (590 mg, 4.27 mmol), and tetrakis(triphenylphosphine)palladium (42 mg, 0.036 mmol) were added. The air in the round-bottom flask was removed by two cycles of vacuuming and nitrogen filling. Subsequently, tetrahydrofuran (60 mL) and water (20 mL) were added to the flask, and the mixture was refluxed at 66° C. under nitrogen atmosphere overnight. The reaction progress was monitored by thin layer chromatography (TLC).
[0076] After the reaction of the raw materials was complete, the mixture was extracted three times with dichloromethane and washed with water. The organic layer was separated and dried over anhydrous sodium sulfate. After evaporation of the solvent, the crude product was purified by silica gel column chromatography using petroleum ether / dichloromethane (2 / 1, V / V) as the eluent. The eluent containing the product was dried by spin drying to obtain a red powder of the intermediate molecule (271 mg, 73.9%). 1 HNMR (400MHz, Chloroform-d): δ7.88(d,J=7.6Hz,2H),7.76(s,2H),7.50(d,J=7.6Hz,2H),7.10(s,2H),6.87(d,J=8.0Hz,6H),3.83(s,6H).
[0077] 2. Synthesis of triphenylamine derivatives: In a 150 mL two-necked round-bottom flask, add the intermediate molecule (150 mg, 0.28 mmol), 4-ethynylpyridine (40 mg, 0.388 mmol), cuprous iodide (23 mg, 0.12 mmol), and tetrakis(triphenylphosphine)palladium (47 mg, 0.04 mmol). Remove air from the round-bottom flask by two cycles of vacuuming and nitrogen filling. Subsequently, triethylamine (20 mL) was added to the flask and refluxed overnight at 90°C under nitrogen. The reaction progress was monitored by thin-layer chromatography (TLC).
[0078] After the reaction of the raw materials was complete, the crude product was purified by silica gel column chromatography using dichloromethane / methanol (40 / 1, V / V) as eluent to obtain PS-3 as a purple-red powder (60 mg, 39.6%), which was recorded as the triphenylamine derivative PS-3. 1 HNMR (400MHz, Chloroform-d): δ8.68–8.62(m,2H),7.90(d,J=7.4Hz,1H),7.87–7.80(m,2H),7.67(d,J =7.6Hz,1H),7.54–7.49(m,2H),7.17–7.12(m,4H),7.06–7.02(m,2H),6.90–6.84(m,4H),3.82(s,6H). 13 C NMR (101MHz, CDCl3): δ156.24,155.15,153.01,149.66,149.41,140.06,135.38,133.88,130.92,129.7 9,127.68,127.09,125.77,125.52,119.14,114.68,113.04,92.16,89.88,77.16,76.84,76.52,55.35.
[0079] The obtained triphenylamine derivatives were characterized by nuclear magnetic resonance spectroscopy, see Figures 2 to 5 It can be seen that the chemical structures of the intermediate molecules and triphenylamine derivatives prepared in Examples 1 to 3 above are consistent with the designed synthesis targets.
[0080] Weigh 2.12 mg, 2.23 mg, and 2.22 mg of PS-1, PS-2, and PS-3, respectively, and dissolve them in 2 mL of THF to prepare a 2 mM stock solution. Prepare 10 5 mL sample vials and first add 0, 0.2, 0.4, 0.6, 0.8, 1.0, 1.2, 1.4, 1.6, and 1.8 mL of ultrapure water; then 1.9, 1.7, 1.5, 1.3, 1.1, 0.9, 0.7, 0.5, 0.3, and 0.1 mL of THF. Add 100 μL of the PS-1, PS-2, and PS-3 stock solutions and mix thoroughly. A total volume of 2 mL is prepared, with a 200 μM concentration. The volume ratios of water are 0%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, and 90%, respectively. After uniform dispersion, the sample was photographed indoors under 365nm UV light. The sample was then added to a quartz cuvette and the fluorescence intensity was measured under different water volumes.
[0081] See also Figure 6 Images of THF / water mixed solutions of PS-1, PS-2, and PS-3 (200 μM) in different water volumes under a) indoor conditions and b) UV light at 365 nm; Fluorescence spectra (excitation wavelength λ) of c) PS-1, d) PS-2, and e) PS-3 at a final concentration of 200 μM in THF / water systems with different water volumes. PS1 =460nm,λ PS2 =480nm,λ PS3 =480nm); f) comparison of the fluorescence spectra of PS-1, PS-2, and PS-3 at a peak of 680nm with increasing volume of water), from Figure 6 As can be seen from ab in Figure 1, as the water volume increases, the solution changes from clear and transparent to turbid under indoor lighting, and under 365nm light source, the solution changes from no fluorescence to strong red fluorescence. Figure 6 As shown in cf., their fluorescence spectra results show that as the volume of the poor solvent in the equal amount of solvent increases, the fluorescence intensity becomes stronger, indicating that the triphenylamine derivatives PS-1, PS-2, and PS-3 exhibit obvious aggregation-induced emission effect.
[0082] Prepare 2mM THF mother solutions of PS-1, PS-2 and PS-3 respectively, and prepare aqueous solutions with pH values from 1 to 8 using hydrochloric acid and sodium hydroxide solutions. Add 100μL of the mother solutions and 1.9mL of the prepared pH solution to a fluorescence quartz cuvette to obtain the f w =95% aqueous solution of different pH values. PS-1 was excited with 460nm excitation wavelength, and the change of its peak fluorescence intensity in solutions of pH=1 to pH=8 was tested (PS-2 and PS-3 were both excited at 480nm).
[0083] like Figure 7 As shown in the figure, PS-1, PS-2, and PS-3 all show purple in aqueous solution at pH = 1. As the pH value increases, the color of the PS-1 solution changes to orange, and the colors of the PS-2 and PS-3 solutions gradually turn red. Figure 8 As shown, the fluorescence intensity of the three triphenylamine derivatives gradually increases with decreasing acidity, with the fluorescence intensity ranking from high to low as PS-1 > PS-2 > PS-3. The fluorescence intensity of PS-3 is relatively weak, remaining stable at weakly acidic pH = 6, neutral pH = 7, and weakly alkaline pH = 8.
[0084] It can be seen that PS-1, PS-2, and PS-3 exhibit obvious aggregation-induced emission effects and can respond to changes in pH of acid solutions by changing color. This is because the triphenylamine derivatives PS-1, PS-2, and PS-3 all have pyridine groups, and the pyridine functional group undergoes protonation reaction in an acidic environment. The principle is based on acid-base reaction, in which pyridine acts as a Lewis base and can accept protons (H + ) to form protonated pyridine. The nitrogen atom on the pyridine ring has a lone pair of electrons that can form a covalent bond with the proton in the acid, resulting in the protonation of the nitrogen atom on the pyridine ring.
[0085] Therefore, the triphenylamine derivative prepared by the present invention can be applied in fields related to pH color change response, such as monitoring changes in acid solution concentration.
[0086] Application Example 1:
[0087] The triphenylamine derivatives PS-1, PS-2 and PS-3 prepared in Examples 1 to 3 were wet-spun with cellulose to prepare fibers with pH color change response.
[0088] This application example prepares pH-responsive color-changing fibers, specifically comprising the following steps:
[0089] (1) Take three 50 mL round-bottom flasks, add 12.57 g of ionic liquid 1-butyl-3-methylimidazolium chloride, 5.92 g of DMSO (ionic liquid: DMSO mass ratio 68:32), 1.18 g of microcrystalline cellulose and magnetron, place it in a constant temperature magnetic stirrer at 95 ° C and stir for 2 hours to dissolve the cellulose evenly. The dissolved spinning solution is transparent. Take 5.9 mg of PS-1, PS-2, and PS-3 and add them to the spinning solution respectively to prepare a cellulose spinning solution with a content of 0.5 wt%, and then place it in a magnetic stirrer and stir it thoroughly.
[0090] Among them, the ionic liquid needs to be freeze-dried in a freeze dryer for 48 hours before use to ensure its dryness.
[0091] (2) Defoaming of spinning solution
[0092] Pour the fully dissolved spinning solution in step (1) into the spinning tank and tighten the lid at the air inlet. Close the spinning hole at the lower end, place the spinning tank in a closed environment, and adjust the gas pressure to 3 Bar (slightly higher than the air pressure during spinning) through an air compressor for 10 minutes for defoaming treatment. Observe whether there are still tiny bubbles. If so, repeat the above steps. If not, spin directly. Increasing the air pressure is to eliminate the tiny bubbles in the spinning solution, so that the surface of the spun fiber is smoother.
[0093] (3) Spinning
[0094] Open the spinning port at the bottom of the spinning pot and install a 21G spinning needle (0.51mm inner diameter). Adjust the pot height so that the spinning tank filled with coagulation bath water covers the needle. Turn on the air compressor and adjust the pressure to 2.5 bar. The spun fibers are pulled through the coagulation bath and evenly collected onto a reel.
[0095] (4) Solution replacement
[0096] After all the fibers were collected, they were soaked in water for about 2 hours to allow the solution to be exchanged with the water. They were then placed in a room to dry naturally. Finally, the pH-responsive fibers PS-1, PS-2, and PS-3 were produced.
[0097] Application Example 2:
[0098] The steps are the same as in Example 1, except that 1.18mgPS-1, PS-2, and PS-3 are added to the spinning solution to form a cellulose spinning solution having a content of 0.1wt%.
[0099] Application Example 3:
[0100] The steps are the same as those in Application Example 1, except that 11.8 mg of PS-1, PS-2, and PS-3 are added to the spinning solution respectively to prepare a cellulose spinning solution with a content of 1 wt%.
[0101] In the present invention, pH-responsive fibers can be prepared by adding 0.1-1 wt% of triphenylamine derivatives into the cellulose spinning solution. The prepared fibers have pH color response characteristics, and the response time of response fibers with different contents is slightly different.
[0102] Test Example 1:
[0103] See also Figure 9 The pH-responsive fiber PS-1 Fiber prepared in Example 1 is orange-red in color, while the colors of PS-2 Fiber and PS-3 Fiber tend to be red.
[0104] Thermal field emission scanning electron microscopy was used to investigate the surface and cross-sectional micromorphological changes of the three pH-responsive fibers, and compared with the control cellulose fibers (Cellulose Fiber). The surface morphology and cross-sectional morphology of the responsive fibers were observed under an electron scanning microscope at 200 times and 5000 times. The surfaces of the control cellulose fibers and the pH-responsive fibers were both grooved, and the direction of the grooves was consistent with the spinning direction. The cellulose in the spinning solution solidified when it came into contact with water, so the surface formed uneven grooves. No granular substances appeared on the surface, indicating that the triphenylamine derivatives PS-1, PS-2, and PS-3 were evenly blended with the spinning solution and evenly distributed in the fibers. After quenching, the cross-sectional morphology of the fibers was observed. Figure 10-11 It can be seen that the cross section is uneven, the structure is dense, and there is no pore structure.
[0105] Test Example 2
[0106] We selected strong acids such as sulfuric acid, medium-strong acids such as phosphoric acid, and weak acids such as acetic acid. We prepared five different acid solutions at concentrations of 0.1M, 0.5M, 1M, 2.5M, and 5M. We placed pH-responsive fibers in these solutions. When the fibers were exposed to the acid solutions, their color gradually changed to purple. PS-1, PS-2, and PS-3 fibers all exhibited color-changing responses to varying concentrations of sulfuric acid, phosphoric acid, and acetic acid. The fiber response time was recorded by observing the color changes.
[0107] The response time of pH-responsive fibers in different acid solutions is shown in Table 1, Table 2, and Table 3:
[0108] Table 1 Response time of pH-responsive fibers to different concentrations of sulfuric acid
[0109]
[0110]
[0111] Table 2 Response time of pH-responsive fibers to different concentrations of phosphoric acid
[0112]
[0113] Table 3 Response time of pH response fiber to different concentrations of acetic acid
[0114]
[0115] From the table, we can see that for the same concentration of acid solution, PS-2Fiber responds faster, followed by PS-3Fiber, and PS-1Fiber has the longest response time. The response time is related to the electronic structure of PS-1, PS-2, and PS-3. When the HOMO-LUMO gap is small, it is easier for the electrons of the molecule to jump from one orbital to another. In the protonation reaction, the smaller the HOMO-LUMO gap, the more reactive the molecule is and the easier it is to accept protons (H + ), thereby shortening the response time.
[0116] Since the three pH-responsive fibers have different response times in acid solutions of different concentrations and strengths, the concentration range of a known acid solution can be predicted by the changes in their color and response time.
[0117] Test Example 3
[0118] The fibers were immersed in a 0.5M sodium hydroxide aqueous solution to restore their response. The recovery time of PS-1 Fiber, PS-2 Fiber, and PS-3 Fiber at different concentrations was observed. The results are shown in Tables 4, 5, and 6.
[0119] Table 4 Recovery time of pH-responsive fibers after response to different concentrations of sulfuric acid (alkaline environment)
[0120]
[0121] Table 5 Recovery time of pH-responsive fibers after response to different concentrations of phosphoric acid (alkaline environment)
[0122]
[0123] Table 6 Recovery time of pH-responsive fibers after response to different concentrations of acetic acid (alkaline environment)
[0124]
[0125] It can be seen from the above table that the color recovery time of the fiber in the alkaline environment of sodium hydroxide can be shortened to 0.1s at the fastest.
[0126] Select 0.5M sulfuric acid solution for response test and 0.5M sodium hydroxide solution for response recovery test. Figure 12 As shown in the figure, after the first immersion, the fiber loses its fluorescence in the acidic solution and the fluorescence intensity decreases. When the fiber is immersed in the sodium hydroxide solution, the fluorescence can be quickly restored. After 5 cycles of response, the fluorescence of the fiber remains at a stable level before and after the response.
[0127] Therefore, the pH-responsive color-changing fibers prepared in the present invention can be restored and recycled after the response.
[0128] Test Example 4
[0129] The pH-responsive fiber was treated in an acidic solution with pH = 1, and the thermal stability of the prepared sample was tested using a thermogravimetric analyzer. The changes in the thermogravimetric analysis graphs before and after the response were analyzed. The results are shown in Figure 13 .
[0130] By comparison, it was observed that the mass loss temperature of the response fiber was still concentrated in the range of 100°C and 290°C, indicating that the pH change did not affect the main component of the response fiber, cellulose, and the response components PS-1, PS-2, and PS-3 were not affected during the decomposition of hemicellulose. The test shows the temperature range of pH-responsive fibers. When the temperature is below 290°C, responsive fibers based on cellulose have a wide range of applications.
[0131] At the same time, after the above cyclic response, the surface morphology of PS-1Fiber, PS-2Fiber and PS-3Fiber was analyzed, such as Figure 14 As shown in the figure, the surface of the fiber still has grooves after the response, which is consistent with that before the response. This also shows that the protonation reaction of the pH-responsive fiber in the solution does not damage the surface morphology.
[0132] The triphenylamine derivative prepared by the present invention exhibits an aggregation-induced luminescence effect and can respond to pH changes in an acid solution by changing color, thereby realizing the pH color change response of the aggregation-induced luminescence molecule in an in vitro solvent; the triphenylamine derivative is mixed with cellulose and then wet-spun to prepare a pH color-responsive fiber, which can also respond to changes in the concentration of the acid solution.
[0133] The pH color-changing responsive fiber prepared by the present invention has different response times to acid solutions of different concentrations and strengths. This characteristic can be used to predict the concentration range of a known acid solution; the pH color-changing responsive fiber prepared by the present invention has good thermal stability, can be restored to its original color after alkali treatment, and can be recycled multiple times.
[0134] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.
Claims
1. A triphenylamine derivative, characterized in that Selected from the following structures:
2. The method for preparing the triphenylamine derivative according to claim 1, wherein: The following steps are involved: S1, [4-[bis(4-methoxyphenyl)amino]phenyl]boronic acid and 4,7-dibromo-2,1,3-benzothiadiazole undergo Suzuki reaction to synthesize an intermediate molecule; S2 and the intermediate molecule react with 4-vinylpyridine and 4-ethynylpyridine respectively to obtain triphenylamine derivative (2) and triphenylamine derivative (3); The structural formula of the intermediate molecule is:
3. The method for preparing a triphenylamine derivative according to claim 2, wherein: The step S1 comprises: mixing [4-[bis(4-methoxyphenyl)amino]phenyl]boric acid, 4,7-dibromo-2,1,3-benzothiadiazole, potassium carbonate and tetrakis(triphenylphosphine)palladium, adding a reaction solvent under an inert gas environment for sufficient reaction, and obtaining an intermediate molecule through post-treatment; the reaction solvent is tetrahydrofuran and water.
4. The method for preparing a triphenylamine derivative according to claim 3, wherein: The step S2 comprises: mixing the intermediate molecule, 4-vinylpyridine, palladium acetate and tri(o-methylphenyl)phosphine, adding a reaction solvent under an inert environment to fully react, and obtaining a triphenylamine derivative (2) through post-treatment; the reaction solvent is triethylamine and N,N-dimethylformamide.
5. The method for preparing a triphenylamine derivative according to claim 3, wherein: The step S2 comprises: mixing the intermediate molecule, 4-ethynylpyridine, cuprous iodide and tetrakis(triphenylphosphine)palladium, adding a reaction solvent under an inert environment to fully react, and obtaining a triphenylamine derivative (3) through post-treatment; the reaction solvent is triethylamine.
6. Use of the triphenylamine derivative according to claim 1 in pH-responsive color change.
7. A method for preparing a pH-responsive color-changing fiber, characterized by: The preparation method comprises: adding the triphenylamine derivative according to claim 1 to a cellulose spinning solution, and preparing the pH-responsive color-changing fiber by wet spinning.
8. The method for preparing a pH-responsive color-changing fiber according to claim 7, wherein: The solvents in the cellulose spinning solution are dimethyl sulfoxide and ionic liquid 1-butyl-3-methylimidazolium chloride, and the mass proportion of the triphenylamine derivative in the cellulose spinning solution is 0.1% to 1%.
9. pH-responsive color-changing fiber prepared by the preparation method according to claim 7 or 8.