Fluorescent probe for identifying fluorine ions and preparation method and identification method thereof

Abstract

The invention provides a probe molecule for identifying fluorine ions and a preparation method and an identification method thereof. The preparation method comprises the following steps: 1) carrying out an amide condensation reaction on Boc-L-phenylalanine and octadecylamine to obtain a product A; 2) removing an amino protecting group (Boc) from the product A through trifluoroacetic acid to obtain a product B; 3) dissolving 4-(1, 2, 2-triphenylvinyl) aniline in dichloromethane, adding triethylamine, adding sulfur phosgene in an ice bath, and reacting at room temperature for 4 hours to obtain a product C; and 4) reacting the product B and the product C in dichloromethane at room temperature for 5 hours to obtain the probe molecule. The synthesis method is simple, and the prepared probe molecule can realize rapid, sensitive and accurate detection of fluorine ions, has high efficiency in practical application, and is especially suitable for detection of trace and trace fluorine ions. The fluorescent probe is high in fluorine ion detection selectivity, the lowest detection limit is 8.7 * 10 <-7 > mol / L, a good logarithmic linear quantitative relation is shown in the range of 0-75 micromol / L, and the fluorescent probe is suitable for trace detection.

Description

Technical Field

[0001] The invention relates to a fluoride ion probe and a preparation method and an identification method thereof, in particular to a probe for identifying fluoride ions through ultraviolet absorption spectrum and a preparation method and an identification method thereof. Background Art

[0002] The identification and detection of anions play an important role in the fields of medicine, industry and environmental testing. Among the many anions, fluoride ions have received widespread attention due to their important biomedical significance. Fluorine plays an important role in the human body, participates in the body's metabolism, maintains normal life activities, and is an essential trace element for the human body. Low concentrations of fluoride ions can effectively prevent tooth decay, however, high concentrations of fluoride ions can cause fluoride poisoning, causing tooth and bone lesions, urinary stones, and even endangering life. Therefore, identifying and monitoring the concentration of fluoride ions is crucial to preventing fluoride poisoning.

[0003] There are many methods for detecting fluoride ions, such as ion selective electrode method, atomic absorption spectrometry and ion chromatography, but these methods are relatively costly, time-consuming, complex sample preparation process, and require relatively expensive instruments, which limit the application of these detection methods in practice. Therefore, it is of great practical significance to establish a simple, fast, accurate and economical fluoride ion monitoring system.

[0004] Based on the above theoretical foundation, in this patent, a fluoride ion probe molecule based on thiourea structure was designed and synthesized. The probe forms a specific hydrogen bond with fluoride ions through the NH donor in the thiourea group, which then triggers the intramolecular charge transfer (ICT) effect, and finally presents a significant characteristic response in the ultraviolet absorption spectrum. Summary of the invention

[0005] In view of the above problems, the present invention aims to provide a fluorescent probe for detecting fluoride ions with a simple system, convenient operation, high sensitivity and good selectivity. The present invention has the characteristics of simple synthesis, mild reaction conditions and low cost.

[0006] The technical solution of the present invention:

[0007] A fluorescent probe for recognizing fluoride ions, the molecular formula of the probe is C 54 H 67 N3OS, the structural formula is:

[0008]

[0009] A method for preparing the aforementioned fluorescent probe for identifying fluoride ions comprises the following steps:

[0010]

[0011] 1) Boc-L-phenylalanine and octadecylamine are dissolved in an organic solvent, and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and 1-hydroxybenzotriazole are added thereto. The mixture is stirred at room temperature for 12 h. After the reaction is completed, the reaction solution is washed with 2 mol / L hydrochloric acid solution and saturated brine respectively. The organic phase is dried over anhydrous sodium sulfate, and the solvent is removed under reduced pressure to obtain Product A.

[0012] 2) Product A is dissolved in an organic solvent, trifluoroacetic acid is added under an ice bath, and the reaction is carried out at 0 °C for 3 h. After the reaction is completed, the solvent is removed under reduced pressure. The concentrate is dissolved in tetrahydrofuran and then poured into a saturated aqueous sodium bicarbonate solution to precipitate a solid. The precipitated solid is filtered and dried to obtain Product B.

[0013] 3) 4-(1,2,2-Triphenylethenyl)aniline is dissolved in an organic solvent, triethylamine is added, and thiophosgene is added under an ice bath. The reaction is carried out at room temperature for 4 h. After the reaction is complete, the reaction is quenched with water, and the organic phase is washed successively with water and saturated brine solution. The organic layer is dried over anhydrous sodium sulfate, and the solvent is removed under reduced pressure to obtain Product C.

[0014] 4) Product B is dissolved in an organic solvent, Product C is added, and the reaction is carried out at room temperature for 5 h. After the reaction is completed, the solvent is removed under reduced pressure to obtain the probe molecule.

[0015] The preparation method of the aforementioned fluorescent probe for recognizing fluoride ions, in the step 1), the molar ratio of Boc-L-phenylalanine, octadecylamine, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and 1-hydroxybenzotriazole is (1.2 - 3.0):1:(1.2 - 3.0):(1.2 - 3.0).

[0016] The preparation method of the aforementioned fluorescent probe for recognizing fluoride ions, in the step 1), the organic solvent used for preparing Product A is one of dichloromethane, chloroform and N,N-dimethylformamide.

[0017] The preparation method of the aforementioned fluorescent probe for recognizing fluoride ions, in the step 2), the volume ratio of dichloromethane to trifluoroacetic acid is (2 - 5):1.

[0018] The preparation method of the aforementioned fluorescent probe for recognizing fluoride ions, in the step 3), the molar ratio of 4-(1,2,2-triphenylethenyl)aniline, triethylamine and thiophosgene is 1:(1.5 - 5.0):(1.2 - 3.0).

[0019] The preparation method of the aforementioned fluorescent probe for recognizing fluoride ions, in the step 4), the molar ratio of Product B to Product C is 1:(1.0 - 3.0).

[0020] Characterization of the probe:

[0021] 1H NMR (600 MHz, CDCl3): δ 7.63 (s, 1H), 7.23 (d, J = 7.3 Hz, 1H), 7.22 (s, 1H), 7.18 (d, J = 1.9 Hz, 1H), 7.17 (d, J = 1.7 Hz, 1H), 7.15 (s, 1H), 7.14 (d, J = 2.2 Hz, 1H), 7.13 (d, J = 1.4 Hz, 1H), 7.13 - 7.12 (m, 2H), 7.10 (d, J = 1.4 Hz, 1H), 7.10 (d, J = 2.4 Hz, 1H), 7.04 (d, J = 2.4 Hz, 1H), 7.03 (d, J = 1.7 Hz, 1H), 7.01 (s, 1H), 7.01 (d, J = 2.5 Hz, 1H), 6.73 (d, J = 8.5 Hz, 1H), 6.70 (d, J = 7.6 Hz, 1H), 5.82 (t, J = 5.7 Hz, 1H), 5.09 (td, J = 8.1, 6.8 Hz, 1H), 3.24 (dd, J = 13.8, 6.7 Hz, 1H), 3.18 (dq, J = 13.5, 7.1 Hz, 1H), 3.12 - 3.04 (m, 1H), 2.98 (dd, J = 13.8, 8.4 Hz, 1H), 1.61 (s, 1H), 1.26 (m, 11H), 1.23 (s, 1H), 1.16 (t, J = 7.4 Hz, 1H), 0.88 (t, J = 7.0 Hz, 2H).

[0022] A method for identifying a fluoride ion using the aforementioned fluorescence probe is to dissolve the probe in tetrahydrofuran, dilute it with water to obtain a probe solution, then add the sample to be identified dropwise to the solution, and then measure the ultraviolet absorption spectrum of the sample. Brief Description of the Drawings

[0023] Figure 1 It is a graph showing the change in the absorption spectrum of the probe of the present invention in the presence of different concentrations of fluoride ions.

[0024] Figure 2 It is a graph showing the relationship between the absorbance of the probe solution at 265 nm and the concentration of fluoride ions and its linear fitting equation.

[0025] Figure 3 It is a logarithmic curve between the absorbance of the absorption peak of the probe solution at 265 nm and the concentration of fluoride ions in the range of 0 - 75 μmmol / L.

[0026] Figure 4 It is a graph showing the relationship between the absorbance of the probe solution at 295 nm and the concentration of fluoride ions and its linear fitting equation.

[0027] Figure 5It is a bar graph showing the changes in the ultraviolet absorption spectrum of the probe selectively identifying fluoride ions at 265 nm when there are other coexisting anions in the solution.

[0028] Figure 6 It is the nuclear magnetic resonance hydrogen spectrum of the fluorescent probe molecule. DETAILED DESCRIPTION

[0029] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0030] This patent introduces a thiourea group that can provide double hydrogen bonds and a tetraphenylethylene structure with aggregation-induced emission effect (this type of molecule emits strong fluorescence when in an aggregated state or solid state, and this phenomenon is named aggregation-induced emission) into the molecule, which provides a good application prospect for the detection of fluoride ions in aqueous solution.

[0031] The present invention uses ultraviolet-visible absorption spectroscopy to detect changes in the absorption spectrum after adding various anions to the probe solution to identify anions. Studies have found that the probe specifically binds to fluoride ions, causing changes in the probe's ultraviolet absorption spectrum, and this specific recognition result is not interfered by other anions; at the same time, the minimum detection limit and linear measurement range of the probe's recognition of fluoride ions are determined by data calculation.

[0032] Example:

[0033] Synthesis steps of probe molecules:

[0034] Boc-L-phenylalanine (2.147 g, 8.1 mmol, 1.5 equiv.) was dissolved in dichloromethane (150 ml), and octadecylamine (1.458 g, 5.4 mmol, 1.0 equiv.), 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (1.557 g, 8.1 mmol, 1.5 equiv.) and 1-hydroxybenzotriazole (1.095 g, 8.1 mmol, 1.5 equiv.) were added to the above solution. After reacting at room temperature for 12 hours, the reaction solution was concentrated under reduced pressure and washed with 2 mol / L hydrochloric acid solution (3×50 ml) and saturated brine (3×50 ml) in sequence. The organic phase was dried over anhydrous sodium sulfate and then concentrated by rotary centrifugation to obtain 2.69 g (5.2 mmol, yield 95.5%) of product A.

[0035] Dissolve 2.69 g of Product A in 10 mL of dichloromethane. Add 4 mL of trifluoroacetic acid under an ice bath. After stirring the reaction at 0 °C for 3 h, remove the organic solvent by rotary evaporation under reduced pressure to obtain an oily product. Dissolve the oily product in 10 mL of tetrahydrofuran (THF), pour it into 100 mL of saturated sodium bicarbonate aqueous solution, precipitate out, filter the precipitated solid, and dry it to obtain 2.0 g (4.8 mmol, yield 92.9%) of Product B.

[0036] Dissolve 0.97 g of 4-(1,2,2-triphenylethynyl)aniline (2.8 mmol, 1.0 equiv.) and 1.2 mL of triethylamine (8.4 mmol, 3.0 equiv.) in 30 mL of dichloromethane. Then add 0.30 mL of thiophosgene (3.9 mmol, 1.4 equiv.) under an ice bath and react at room temperature for 4 h. After the reaction is complete, quench with water. Wash the organic phase successively with water and saturated brine solution, dry the organic phase with anhydrous sodium sulfate, and remove the solvent under reduced pressure to obtain a crude product. After purification by column chromatography, 0.94 g (2.4 mmol, yield 84%) of light yellow solid Product C is obtained.

[0037] Dissolve 0.30 g of Product C (0.77 mmol, 1.0 equiv.) in 5 mL of dichloromethane, and then slowly drop it into dichloromethane (5 mL) dissolved with 0.32 g of Product B (0.77 mmol, 1.0 equiv.). Stir the reaction at room temperature for 5 h. After the reaction is complete, remove the organic solvent under reduced pressure to obtain a crude product. Purify the crude product by column chromatography to obtain 0.4 g of the probe molecule (0.5 mmol, yield 65%).

[0038] Recognition and detection of fluoride ions by the probe:

[0039] Weigh 80.6 mg of the probe, dissolve it in 100 mL of tetrahydrofuran to prepare a stock solution with a concentration of 1.0×10 -4 mol / L. Then pipette 50 μL of the stock solution and dilute it to 5 mL with a mixed solvent of tetrahydrofuran:water = 4:1 to obtain a probe solution with a concentration of 1.0×10 -5 mol / L.

[0040] As Figure 1 shown, add different concentrations of fluoride ions to a 10 μmol / L probe molecule solution to prepare probe molecule solutions with fluoride ion concentrations of 0, 5, 10, 25, 50, 75, 100, 150, 200, 250, 350, 500 μmol / L, and measure their absorption spectra. It can be seen from the figure that when the F - concentration increases, the absorbance first increases. However, when the F -When the concentration exceeds 75 μmol / L, the absorbance begins to decrease; meanwhile, it is found that as the F - concentration increases, the absorption peak at 295 nm gradually disappears, and the absorption peak at 265 nm gradually weakens.

[0041] As Figure 2 shown, the absorbance of the absorption peak of the probe solution at 265 nm shows a linear relationship between fluoride ion concentrations of 75 - 500 μmol / L. Its linear equation is y = -0.0009x + 0.5889, and R 2 = 0.9563.

[0042] As Figure 2 shown, the absorbance of the absorption peak of the probe solution at 265 nm shows a logarithmic curve relationship between fluoride ion concentrations of 0 - 75 μmol / L. Therefore, taking Inc as the abscissa and absorbance as the ordinate, we get Figure 3 .

[0043] As Figure 3 shown, Inc and absorbance show a good linear relationship, R 2 = 0.9823. The detection limit calculated using the 3σ IUPAC standard is 8.7×10 -7 mol / L.

[0044] As Figure 4 shown, the absorbance of the absorption peak of the probe solution at 295 nm shows a linear relationship between fluoride ion concentrations of 75 - 500 μmol / L. Its linear equation is y = -0.0011x + 0.6224, and R 2 = 0.9761.

[0045] As Figure 5 shown, using the 10 μmol / L probe molecule solution without anions as a blank control, the ultraviolet absorption spectrum at 265 nm was measured; then 500 μmol / L of F - was added to the probe molecule solution, and its absorption spectrum was measured; subsequently, other anions (SO4 2- , HCO3 - , NO2 - , OH - , SO3 2- , Cl - , Br - ) were added respectively to make the anion concentration 500 μmol / L, and the absorption spectrum of the solution was measured. It can be seen from Figure 5 that when there are a large number of other anions in the solution, the selective recognition of fluoride ions by the probe molecule is not affected.

[0046] Figure 6 is the 1H NMR spectrum of the probe molecule.

Claims

1. A probe for identifying fluoride ions, characterized in that: The molecular formula of the probe is C 54 H 67 N3OS, the structural formula is:

2. The method for preparing the fluoride ion recognition probe according to claim 1, characterized in that: The steps include: 1) Compound Boc-L-phenylalanine and octadecylamine are dissolved in an organic solvent, and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and 1-hydroxybenzotriazole are added thereto. The mixture is stirred at room temperature for 12 hours. After the reaction is completed, the reaction solution is washed with 2 mol / L hydrochloric acid solution and saturated brine respectively, the organic phase is dried over anhydrous sodium sulfate, and the solvent is removed under reduced pressure to obtain product A. 2) Dissolve product A in an organic solvent, add trifluoroacetic acid under ice bath, react at 0°C for 3 h. After the reaction is completed, remove the solvent under reduced pressure, dissolve the concentrate in tetrahydrofuran, pour into saturated sodium bicarbonate aqueous solution, filter the precipitate, and dry to obtain product B. 3) Dissolve 4-(1,2,2-triphenylvinyl)aniline in an organic solvent, add triethylamine, add thiophosgene in an ice bath, and react at room temperature for 4 hours. After the reaction is complete, add water to quench, wash the organic phase with water and saturated saline solution in turn, dry the organic layer with anhydrous sodium sulfate, and remove the solvent under reduced pressure to obtain product C. 4) Dissolve product B in an organic solvent, add product C, and react at room temperature for 5 hours. After the reaction is completed, remove the solvent under reduced pressure to obtain the probe.

3. The method for preparing a fluorescent probe for identifying fluoride ions according to claim 2, characterized in that: In the aforementioned method for preparing a fluorescent probe for recognizing fluoride ions, in step 1), the molar ratio of Boc-L-phenylalanine, octadecylamine, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and 1-hydroxybenzotriazole is (1.2-3.0):1:(1.2-3.0):(1.2-3.0).

4. The method for preparing a fluorescent probe for recognizing fluoride ions according to claim 2, characterized in that: The organic solvent used to prepare product A is one of dichloromethane, chloroform and N,N-dimethylformamide.

5. The method for preparing a fluorescent probe for identifying fluoride ions according to claim 2, characterized in that: The volume ratio of dichloromethane to trifluoroacetic acid is (2-5):

1.

6. The method for preparing a fluorescent probe for recognizing fluoride ions according to claim 2, characterized in that: The molar ratio of 4-(1,2,2-triphenylvinyl)aniline, triethylamine and thiophosgene is 1:(1.5-5.0):(1.2-3.0).

7. The method for preparing a fluorescent probe for recognizing fluoride ions according to claim 2, characterized in that: The molar ratio of product B to product C is 1:(1.0-3.0).

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