Supramolecular sensor based on pentafluorophenyl-functionalized tetrapod azine and its preparation and application in fluorescence detection of perfluorooctanoic acid

Abstract

The present invention discloses a supramolecular sensor based on pentafluorophenyl functionalized tetrapod azine, which is obtained by using pentafluorobenzaldehyde and 4,4'-biphenyl diphenol tetrahydrazine derivative as reaction substrates. In DMSO solution, the sensor TF5 can undergo supramolecular interaction with perfluorooctanoic acid and fluorescence enhancement occurs at the same time, so it can be used for fluorescence recognition of perfluorooctanoic acid, with a minimum detection limit of 9.27×10 ‑6 M, the sensor TF5 has important application value in the field of detecting perfluorooctanoic acid.

Description

Technical Field

[0001] The present invention relates to a synthesis method of a sensor based on pentafluorophenyl functionalized tetrapod azine. The present invention also relates to the specific application of supramolecular sensor in fluorescence identification of perfluorooctanoic acid (PFOA), belonging to the field of chemical synthesis and dangerous substance detection. Background Art

[0002] Per- and polyfluoroalkyl substances (PFAS) include perfluoroalkyl sulfonic acid, fluorotelomer sulfonic acid and perfluoroalkyl carboxylic acid, which are widely used in the preparation of food packaging bags, anti-fouling and waterproof fabrics, leather and clothing, as well as cleaning products and fire-retardant foams. However, these compounds can pollute groundwater and surface water, which has caused many environmental and health crises. These compounds can also cause damage to human health, including liver damage, thyroid disease, cancer and other diseases. Therefore, people are particularly concerned about the presence of perfluorooctanoic acid (PFOA) in the environment, and the detection of PFOA in the environment has important application value.

[0003] At present, people have developed a variety of PFOA detection methods, and the fluorescence method is a major detection method due to its advantages of simple operation, rapidity, high sensitivity, etc. The present invention is based on the fact that the pentafluorophenyl group has a strong electron-withdrawing property, which has a significant effect on the fluorescence and other properties of the molecule, and the fluorine atoms on the pentafluorophenyl group are fluorine-philic and can effectively bind to PFOA. The use of a tetrapod structure can improve the selectivity of the sensor molecule binding to PFOA and the sensitivity of detection. Summary of the invention

[0004] The object of the present invention is to provide a supramolecular sensor based on pentafluorophenyl functionalized tetrapod azine;

[0005] Another object of the present invention is to provide a method for synthesizing the supramolecular sensor;

[0006] Another object of the present invention is to provide an application of the supramolecular sensor for fluorescent detection of PFOA.

[0007] 1. Synthesis of supramolecular sensors

[0008] The method for synthesizing the supramolecular sensor of the present invention comprises the following steps:

[0009] (1) Preparation of 4,4´-biphenyl tetraaldehyde derivatives: 4,4´-biphenyl diphenol and hexamethylenetetramine are used as substrates, trifluoroacetic acid is used as solvent, and the reaction is carried out at 135-145°C for 70-75 h. After the reaction is completed, dilute hydrochloric acid is added, stirred and filtered, and the product is an orange solid. It is recrystallized from dimethyl sulfoxide to obtain 4,4´-biphenyl diphenol tetraaldehyde derivatives, and the obtained product is recorded as TA. The molar ratio of 4,4´-biphenyl diphenol to hexamethylenetetramine is 1:8-1:10.

[0010] (2) Using hydrazine hydrate and 4,4´-biphenyl tetrahydraldehyde derivative TA as substrates and anhydrous ethanol as solvent, the reaction was carried out at 75-85°C for 20-25 hours. After the reaction, an orange-yellow solid was precipitated, which was filtered and rinsed with hot ethanol to obtain a 4,4´-biphenyl tetrahydrazine derivative, which was recorded as TB. The molar ratio of hydrazine hydrate to TA was 1:2-1:4.

[0011] (3) Using ethanol as solvent and glacial acetic acid as catalyst, pentafluorobenzaldehyde and 4,4´-biphenyl tetrahydrazine derivative TB as reaction substrates, the reaction was carried out at 70-80 °C for 45-50 h, cooled to room temperature, and filtered under reduced pressure to obtain a pale yellow crude product, which was washed with hot anhydrous ethanol to obtain a yellow solid product, which is the supramolecular sensor TF5. The molar ratio of 4,4´-biphenyl tetrahydrazine derivative TB to pentafluorobenzaldehyde is 1:4-1:5. The amount of glacial acetic acid used is 0.02-0.08 times the total molar amount of the reaction substrate.

[0012] The molecular formula of the fluorescent sensor prepared above is: 44 H 14 F 20 N8O2, marked as TF5, has the following synthesis route:

[0013] .

[0014] The mass spectra and hydrogen spectra of intermediates TA and TB are shown in Figure 1 , Figure 2 , Figure 3 and Figure 4 .

[0015] The mass spectrum and infrared spectrum of the sensor molecule TF5 are shown in Figure 5 and Figure 6 .

[0016] 2. Supramolecular sensor TF5 fluorescence detection of PFOA

[0017] 1. Fluorescence properties of supramolecular sensor TF5

[0018] The fluorescence properties of the supramolecular sensor TF5 were studied and it was found that the fluorescence emission of the supramolecular sensor TF5 was low in DMSO solution (e.g. Figure 7 ).

[0019] 2. Supramolecular sensor TF5 fluorescence recognition of PFOA

[0020] In the DMSO solution of the supramolecular sensor TF5, a PFOA aqueous solution was added. The results showed that the addition of PFOA could enhance the fluorescence of the DMSO solution of TF5 (e.g. Figure 7), indicating that the supramolecular sensor TF5 can be used for the qualitative detection of PFOA by fluorescence.

[0021] PFOA solutions of different concentrations were added dropwise to DMSO solution of TF5 (C TF5 =5×10 -5 M), the fluorescence intensity of TF5 was measured and linear fitting was performed. The fluorescence intensity of the supramolecular sensor and the ratio of the concentration of PFOA to the concentration of the supramolecular sensor showed the following linear relationship: Y = 0.84X1 / X2 + 79.59, R 2 =0.9948, where Y is the fluorescence intensity, X1 is the concentration of perfluorooctanoic acid, in mol / L, and X2 is the concentration of the supramolecular sensor, in mol / L. The minimum detection limit of the supramolecular sensor TF5 for PFOA is 9.27×10 -6 M (such as Figure 8 , 9 As shown in Figure 2 ). The concentration of the supramolecular sensor is known, and the concentration of PFOA can be quantitatively detected by substituting the measured fluorescence intensity of the supramolecular sensor into the linear relationship.

[0022] 3. Analysis of recognition mechanism

[0023] In order to study the interaction between TF5 and PFOA, we conducted a systematic study using experimental and quantitative calculation methods. Fig.10 The experiment shows that after adding PFOA, the OH peak and C=N peak in TF5 moved significantly, indicating that there is an interaction between PFOA and OH and C=N. The host-guest mass spectrometry experiment confirmed that TF5 and PFOA interact in a 1:1 manner (as shown in Figure 2). Fig.11 As shown in the quantitative calculation results, it can be seen that the PFOA molecule is wrapped between the four legs of TF5 (as shown in the figure). Fig.12 From the frontier molecular orbital diagrams of TF5 and TF5+PFOA (as shown in Fig.13 As shown in the figure, after adding PFOA, the HOMO-LUMO energy gap increases from 3.274 eV to 3.295 eV, which is attributed to the redistribution of charges in TF5 after adding PFOA. From the charge distribution diagram of TF5 and TF5+PFOA, it can be seen that after adding PFOA, the electronegativity of TF5 increases (as shown in the figure). Fig.14 IGM diagram (as shown). Fig.15 The results show that there is an intermolecular hydrogen bond between TF5 and PFOA. Therefore, the fluorescence of the fluorescent sensor TF5 is enhanced after adding PFOA.

[0024] In summary, the supramolecular sensor TF5 synthesized in the present invention can interact with PFOA in DMSO solution and enhance the fluorescence of TF5, so it can detect PFOA qualitatively and quantitatively with low detection limit and high detection sensitivity, and has good application prospects in the detection of PFOA. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is the mass spectrum of the intermediate TA of the present invention;

[0026] Figure 2 is the hydrogen spectrum of the intermediate TA of the present invention;

[0027] Figure 3 is the mass spectrum of the intermediate TB of the present invention;

[0028] Figure 4 is the hydrogen spectrum of the intermediate TB of the present invention;

[0029] Figure 5 is the mass spectrum of the sensor molecule TF5 of the present invention;

[0030] Figure 6 This is the infrared spectrum of the sensor molecule TF5 of the present invention;

[0031] Figure 7 This is a fluorescence change diagram when PFOA is added to the DMSO solution of the sensor molecule TF5 of the present invention;

[0032] Figure 8 This is a fluorescence titration graph of adding PFOA into a DMSO solution of the sensor molecule TF5 of the present invention;

[0033] Fig. 9 This is the fluorescence titration fitting curve of the sensor molecule TF5 of the present invention to PFOA;

[0034] Fig.10 The infrared spectra of the sensor molecules TF5 and TF5+PFOA of the present invention are shown;

[0035] Fig.11 This is the mass spectrum of the sensor molecule TF5+PFOA of the present invention;

[0036] Fig.12 It is the optimized configuration diagram of the sensor molecules TF5 and TF5+PFOA of the present invention;

[0037] Fig.13 The frontier molecular orbital diagram of the sensor molecules TF5 and TF5+PFOA of the present invention;

[0038] Fig.14 The charge distribution diagram of the sensor molecules TF5 and TF5+PFOA of the present invention;

[0039] Fig.15 This is a diagram of the weak interaction between the sensor molecule TF5 of the present invention and PFOA. DETAILED DESCRIPTION

[0040] The preparation of the sensor molecule TF5 of the present invention and the application of fluorescence recognition of PFOA are further described below through specific examples.

[0041] Example 1. Synthesis of sensor TF5

[0042] (1) Preparation of 4,4´-biphenyl tetraaldehyde derivative: 4,4´-biphenyl tetraaldehyde (0.37 g, 2.0 mmol) and hexamethylenetetramine (2.24 g, 16 mmol) were added to 30 mL of trifluoroacetic acid and reacted at 140 °C for 72 h. After the reaction, dilute hydrochloric acid was added and the mixture was stirred and filtered. The product was an orange solid, which was recrystallized from dimethyl sulfoxide to obtain a 4,4´-biphenyl tetraaldehyde derivative TA.

[0043] (2) Add hydrazine hydrate (0.2 g, 4 mmol) and TA (0.30 g, 1 mmol) to 40 mL of anhydrous ethanol and react at 80 °C for 24 h. After the reaction, an orange-yellow solid precipitates. Filter it and rinse it with hot ethanol. The obtained product is recorded as TB.

[0044] (3) Add pentafluorobenzaldehyde (0.98 g, 5 mmol), 4,4´-biphenyl tetrahydrazine derivative TB (0.35 g, 1 mmol), and glacial acetic acid (1 mL) into 40 mL of ethanol and react at 70-80 °C for 48 h. Cool to room temperature and filter under reduced pressure to obtain a pale yellow crude product. Wash with hot anhydrous ethanol to obtain a yellow solid product, which is the supramolecular sensor TF5.

[0045] Example 2: Fluorescence detection of PFOA by sensor TF5

[0046] Pipette 2 mL of DMSO solution of fluorescent sensor TF5 (C TF5 =5×10 -5 M) in a colorimetric tube, and gradually added PFOA aqueous solution (0.1 M). The fluorescence intensity of the DMSO solution of the sensor molecule increased from 70 to about 140, and the fluorescence intensity was significantly enhanced.

Claims

1. A supramolecular sensor based on pentafluorophenyl-functionalized tetrapod azine, the molecular formula of which is C 44 H 14 F 20 N8O2, the structural formula is: 。 2. The method for synthesizing the supramolecular sensor based on pentafluorophenyl functionalized tetrapod azine as claimed in claim 1, comprising the following steps: (1) Preparation of 4,4´-biphenyl tetraaldehyde derivatives: 4,4´-biphenyl tetraaldehyde and hexamethylenetetramine are used as substrates and trifluoroacetic acid is used as solvent. The reaction is carried out at 135-145°C for 70-75 h. After the reaction is completed, dilute hydrochloric acid is added, stirred and filtered, and the product is an orange solid. It is recrystallized from dimethyl sulfoxide to obtain a 4,4´-biphenyl tetraaldehyde derivative TA. The structural formula of 4,4´-biphenyl diphenol tetraaldehyde derivative TA is: ； (2) Using hydrazine hydrate and 4,4´-biphenyl tetrahydraldehyde derivative TA as substrates and anhydrous ethanol as solvent, the reaction was carried out at 75-85°C for 20-25 hours. After the reaction, an orange-yellow solid was precipitated, which was filtered and washed with hot ethanol to obtain 4,4´-biphenyl tetrahydrazine derivative TB; The structural formula of 4,4´-biphenyl diphenol tetrahydrazine derivative TB is: (3) Using ethanol as solvent, glacial acetic acid as catalyst, pentafluorobenzaldehyde and 4,4´-biphenyl tetrahydrazine derivative TB as reaction substrates, the reaction was carried out at 70-80 °C for 45-50 h, cooled to room temperature, and filtered under reduced pressure to obtain a pale yellow crude product, which was washed with hot anhydrous ethanol to obtain a yellow solid product, which is the supramolecular sensor TF5.

3. The method for synthesizing a supramolecular sensor based on pentafluorophenyl functionalized tetrapod azine according to claim 2, characterized in that: In step (1), the molar ratio of 4,4'-biphenol to hexamethylenetetramine is 1:8 to 1:

10.

4. The method for synthesizing a supramolecular sensor based on pentafluorophenyl functionalized tetrapod azine according to claim 2, characterized in that: In step (2), the molar ratio of 4,4'-biphenyl tetraaldehyde derivative TA to hydrazine hydrate is 1:2 to 1:

4.

5. The method for synthesizing the supramolecular sensor of pentafluorophenyl functionalized tetrapod azine according to claim 2, characterized in that: In step (3), the molar ratio of 4,4'-biphenyl tetrahydrazine derivative TB to pentafluorobenzaldehyde is 1:4 to 1:

5.

6. The method for synthesizing a supramolecular sensor based on pentafluorophenyl functionalized tetrapod azine according to claim 2, characterized in that: In step (3), the amount of glacial acetic acid used is 0.02 to 0.08 times the total molar amount of the reaction substrate.

7. The use of a supramolecular sensor based on pentafluorophenyl functionalized tetrapod azine in fluorescence detection of perfluorooctanoic acid as claimed in claim 1, characterized in that: When an aqueous solution of perfluorooctanoic acid is added to the DMSO solution of the supramolecular sensor molecules, the fluorescence of the DMSO solution of the supramolecular sensor becomes stronger.

8. The use of a supramolecular sensor based on pentafluorophenyl functionalized tetrapod azine in the quantitative detection of perfluorooctanoic acid as claimed in claim 1, characterized in that: The fluorescence intensity of the supramolecular sensor is linearly related to the ratio of the concentration of PFOA to the concentration of the supramolecular sensor as follows: Y = 0.84X1 / X2 + 79.59, R 2 =0.9948, where Y is the fluorescence intensity, X1 is the concentration of PFOA, in mol / L, and X2 is the concentration of the supramolecular sensor, in mol / L. Substituting the measured fluorescence intensity of the supramolecular sensor into the linear relationship can quantitatively detect the concentration of PFOA, and the minimum detection limit is 9.27×10 -6 M.

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