A kind of triphenylamine-based Schiff base Hg 2+ Method for preparing fluorescent probe and application thereof

Abstract

This invention discloses a triphenylamino Schiff base Hg 2+ The fluorescent probe is a triphenylamino Schiff base compound obtained by condensation reaction of 4-(diphenylamino)-2-hydroxybenzaldehyde and 2-aminophenol, and its chemical structure is shown in formula (I). The fluorescent probe of this invention exhibits Hg activity in DMSO:PBS (v / v = 1:1) solution. 2+ It has specific identification capabilities, high sensitivity, and strong anti-interference ability, with a detection limit as low as 0.23 μM; this invention provides a simple and rapid method for detecting Hg. 2+ Fluorescent probes have broad application prospects in the environmental and biological fields.

Description

Technical Field

[0001] This invention belongs to the fields of organic synthesis, fluorescent probes, and fine chemicals, specifically relating to a triphenylamino Schiff base Hg. 2+ Fluorescent probe. Background Technology

[0002] Compared to other heavy metals, mercury is more toxic. Mercury (Hg) is one of the most prevalent and deadly toxins on Earth, a toxic heavy metal that seriously harms the environment and human health, and is widely present in water and soil. Mercury is produced from many sources, such as metallurgy and coal combustion, but primarily from industrial wastewater discharge. With the accelerating pace of industrialization, large amounts of Hg are being produced... 2+ Ions are released into the environment. (Hg) 2+ It exhibits persistent ionic toxicity, is difficult to degrade, and has a high bioaccumulation rate. Meanwhile, Hg deposited in water... 2+ Ultimately, mercury accumulates in the human body through the food chain, causing cellular dysfunction, damaging the central nervous system and endocrine system, and leading to a series of diseases, including acne, Alzheimer's disease, and Huntington's disease. It causes multiple damages to the central nervous system and leads to kidney and stomach dysfunction, posing a significant threat to human health. Therefore, rapid and effective detection of mercury ions is of great importance to human health and environmental protection.

[0003] In recent years, the most commonly used method for detecting Hg 2+ Methods include atomic absorption spectrometry and inductively coupled plasma mass spectrometry, such as gas chromatography, liquid chromatography, capillary electrophoresis, neutron activation analysis, and anodic stripping voltammetry. However, most of these methods are expensive, require large amounts of sample preparation, have long detection times, and can only measure Hg. 2+ Total content. Compared to other methods, fluorescent probes offer advantages such as high sensitivity, good selectivity, simple operation, low cost, and real-time monitoring, and are increasingly attracting attention. Therefore, developing efficient fluorescent probes with good selectivity and sensitivity for the detection of Hg is crucial. 2+ This has significant practical implications. In recent years, the detection of Hg based on rhodamine, fluoroboron dipyrrole, and benzothiazole derivatives has been studied. 2+ There are many reports on this topic, but it has drawbacks such as complex synthesis steps, low compound yield, and the fact that most of them involve fluorescence quenching mechanisms.

[0004] Based on the above considerations, this invention prepares a novel triphenylamine Schiff base fluorescent probe, which is effective against Hg. 2+ It has specific recognition properties, and its synthesis is simple and yield is high; it is similar to Hg. 2+The fluorescence intensity was significantly enhanced after treatment, and the detection limit was low. Due to its advantages such as fast response, high selectivity and sensitivity, and minimal interference from other metal cations, this probe has great application potential. Summary of the Invention

[0005] For existing Hg detection 2+ To address the shortcomings of the existing methods, this invention utilizes molecular design to prepare a triphenylamine Schiff base Hg with good selectivity, high sensitivity, strong anti-interference ability, and low detection limit. 2+ Fluorescent probe.

[0006] The present invention also provides a method for preparing the above-mentioned triphenylamine Schiff base fluorescent probe.

[0007] This invention also provides the application of the above-mentioned triphenylamine Schiff base fluorescent probes in the field of detection.

[0008] Technical solution: To achieve the above-mentioned objective, the technical solution of this invention is a triphenylamino Schiff base Hg 2+ The fluorescent probe has the chemical structure shown in formula (I).

[0009]

[0010] The above triphenylamine Schiff bases Hg 2+ A method for synthesizing a fluorescent probe, characterized in that it is synthesized according to the following experimental steps;

[0011] In the presence of p-toluenesulfonic acid, 4-(diphenylamino)-2-hydroxybenzaldehyde (II) and 2-aminophenol were reacted via an intermolecular condensation reaction to yield compound (I);

[0012] The above-mentioned triphenylamino Schiff bases Hg 2+ The specific synthetic reaction formula for the fluorescent probe is as follows:

[0013]

[0014] The steps are carried out by the following method: 4-(diphenylamino)-2-hydroxybenzaldehyde (II), 2-aminophenol, and p-toluenesulfonic acid (PTSA) are dissolved in N,N-dimethylformamide (DMF), and reacted at 70°C for 7 hours under N2 protection to obtain compound (I);

[0015] The triphenylamine Schiff base fluorescent probe of the present invention reacts with Hg in a dimethyl sulfoxide (DMSO): phosphate buffered saline (PBS) (v / v = 1:1) mixture. 2+ It exhibits a significant fluorescence response signal.

[0016] Prepare a DMSO:PBS (v / v = 1:1) solution for the fluorescent probe (I), and add quantitative amounts of different metal cations, including Ca. 2+ Na + La + Mn 2+ Ba 2+ Ag + Cu 2+ Zn 2+ Cd 2+ Cr 3+ Fe 3+ Fe 2+ Al 3+ Co 2+ Ni + K + Mg 2+ Hg 2 + The selective recognition of different metal cations by probe (I) was studied by measuring their fluorescence emission spectra. The results are as follows: Figure 1 As shown, by examining the changes in fluorescence emission spectral intensity, it was found that the fluorescent probe (I) described in this invention is effective against Hg. 2+ It exhibits strong fluorescence responsiveness; when this fluorescent probe reacts with Hg... 2+ The fluorescence intensity increased significantly after treatment, while other metal ions did not cause significant changes in fluorescence intensity under the same conditions, indicating that this probe is effective against Hg. 2+ It exhibits high specificity and selectivity. Additionally, a certain amount of probe solution was taken, and Hg was gradually added... 2+ Up to 42 μM; the fluorescence intensity of the fluorescent probe (I) gradually increased at 527 nm and reached Hg. 2+ The fluorescence intensity reaches its maximum at 34 μM. Further increasing the mercury ion content results in almost no change in fluorescence intensity, indicating that mercury ion saturation has been reached. The results are as follows: Figure 2 As shown. Fluorescent probe (I) is added with Hg 2+ During the process, the maximum fluorescence emission intensity at 527 nm was selected as the ordinate, Hg 2+ Using concentration as the abscissa, linear fitting yielded two linear regression equations with different ranges: y = 12.69473x + 41.66668 and y = 38.18359x - 513.65845. The results are as follows... Figure 3 As shown, therefore, this fluorescent probe can be used for Hg in this range. 2+ Quantitative analysis and detection.

[0017] The triphenylamino Schiff bases Hg described in this invention 2+ Fluorescent probes for detecting Hg 2+It exhibits superior robustness against various potential competing analytes, as shown in the following results. Figure 4 As shown, the fluorescence intensity of the fluorescent probe (I) hardly changed upon the addition of other analytes, thus confirming that the fluorescent probe (I) described in this invention is effective against Hg in DMSO:PBS (v / v = 1:1) solution. 2+ It has unique fluorescence selectivity and strong anti-interference ability.

[0018] The triphenylamino Schiff bases Hg described in this invention 2+ Fluorescent probes are characterized by short response times, such as Figure 5 As shown, in Hg 2+ In the presence of Hg, the probe exhibits fluorescence enhancement within 1 second, and the fluorescence emission intensity gradually reaches saturation after 2 seconds. This fast-response probe can be used for Hg. 2+ The real-time detection indicates that the probe has high sensitivity.

[0019] The triphenylamino Schiff bases Hg described in this invention 2+ Fluorescent probes exhibit good performance at pH values ​​of 8-12, with a significant decrease in alkaline pH ranges of 10-12. The probes still show strong and stable fluorescence emission for mercury ion recognition. The wide pH range of application helps to improve the actual detection performance of fluorescent probes.

[0020] The beneficial effects of the present invention are: (1) The synthesis method of the fluorescent probe is simple, the reaction conditions are mild, and the purification and separation methods are convenient; (2) The fluorescent probe has good selectivity, strong anti-interference ability, high sensitivity, and a detection limit as low as 0.23 μM, and has broad application prospects in analytical chemistry, environmental detection, food detection and other fields. Attached Figure Description

[0021] Figure 1 The concentration of fluorescent probe (I) is 1×10 -5 Fluorescence emission intensity diagrams of 5 equivalents of different metal ions added to a mol / L DMSO:PBS (v / v = 1:1) solution.

[0022] Figure 2 The concentration of fluorescent probe (I) is 1×10 -5 Hg was carried out in a mol / L DMSO:PBS (v / v = 1:1) solution. 2+ Fluorescence emission intensity titration plot, with the vertical axis representing fluorescence emission intensity and the horizontal axis representing emission wavelength, and the excitation spectrum wavelength being 380 nm.

[0023] Figure 3 The fluorescent probe (I) uses selected concentrations of Hg 2+This is a linear fit graph with the x-axis and the y-axis as the maximum fluorescence emission intensity at the maximum fluorescence emission wavelength of 527 nm; the x-axis represents the result of adding Hg. 2+ The concentration, in units of 10 -5 mol / L.

[0024] Figure 4 The concentration of fluorescent probe (I) is 1×10 -5 mol / L and Hg 2+ A bar chart showing the fluorescence intensity changes at the maximum emission wavelength of 527 nm after adding 5 equivalents of other metal cation competitive analytes to a coexisting DMSO:PBS (v / v = 1:1) solution.

[0025] Figure 5 The concentration of fluorescent probe (I) is 1×10 -5 mol / L Hg-free in DMSO:PBS (v / v = 1:1) solution 2+ and has Hg 2+ The graph shows the change in fluorescence emission intensity over time when it is present.

[0026] Figure 6 The concentration of fluorescent probe (I) is 1×10 -5 mol / L when adding Hg 2+ The graph shows the change in fluorescence intensity before and after pH values. Detailed Implementation

[0027] The present invention will now be described in further detail with reference to embodiments and accompanying drawings.

[0028] Example 1

[0029] Triphenylamine Schiff bases Hg 2+ Preparation of fluorescent probe (I).

[0030] 0.52 mmol of 4-(diphenylamino)-2-hydroxybenzaldehyde (II) and 0.78 mmol of 2-aminophenol were added to a 50 mL reaction flask, followed by 5 mL of LDM and 15 mg of p-toluenesulfonic acid. The reaction was carried out under N2 protection at 70 °C for 7 h. After the reaction was complete, the mixture was cooled to room temperature, poured into 100 mL of deionized water, and extracted with dichloromethane. The organic layer was dried over anhydrous sodium sulfate. The filtrate was evaporated to dryness and purified by silica gel column chromatography (eluents: ethyl acetate and petroleum ether) to obtain a brownish-yellow powder solid (I) in 70% yield. 1H NMR (600MHz, DMSO-d6, ppm): 14.18 (s, 1H), 9.65 (s, 1H), 8.79 (s, 1H), 7.41-7.37 (q, J=7.8Hz, 6H), 7.32 (d, J=7.8Hz, 1H), 7.19 (s, 1H), 7.17 (d , J=7.8Hz, 4H), 7.08-7.05 (m, 1H), 6.93-6.92 (m, 1H), 6.86-6.84 (m, 1H), 6.34 (dd, J=8.4Hz, J=2.4Hz, 1H), 6.16 (d, J=1.8Hz, 1H); Esi-HRMS [C 25 H 21 N2O2 + The theoretical value is 381.1598[M+H] + The actual measured value is 381.1590.

[0031] Example 2

[0032] Study on the selective recognition of different metal ions by triphenylamine Schiff base fluorescent probe (I).

[0033] Prepare a precise DMSO:PBS (v / v = 1:1) solution of 10 μM fluorescent probe (I). Figure 1 As shown, 5 equivalents of different metal ions, such as Hg, are added to the test solution containing the fluorescent probe (I). 2+ Ca 2+ Na + La + Mn 2+ Ba 2+ Ag + Cu 2 + Zn 2+ Cd 2+ Cr 3+ Fe 3+ Fe 2+ Al 3+ Co 2+ Ni - K + Mg 2+ It was discovered that only by adding Hg 2+ Subsequently, the fluorescence intensity of the fluorescent probe (I) at 527 nm was significantly enhanced. The fluorescence intensity of the probe remained almost unchanged after the addition of other metal cations, indicating that, except for Hg... 2+ In addition, the other metal ions studied had almost no significant effect on the fluorescence spectrum of probe (I), indicating that the fluorescent probe (I) has a positive effect on Hg. 2+ It has high specificity and selectivity and can be used as a detection method for Hg.2+ Specific fluorescent probes.

[0034] Example 3

[0035] Triphenylamine Schiff base fluorescent probe (I) with Hg 2+ Graph showing the change in fluorescence intensity with increasing concentration.

[0036] The fluorescence intensity of the fluorescent probe (I) and Hg were further investigated using titration experiments. 2+ Linear relationship between concentrations. Hg was detected in a 10 μM fluorescent probe (I) DMSO:PBS (v / v = 1:1) solution. 2+ Fluorescent titration, such as Figure 2 As shown, in the absence of Hg 2+ Under these conditions, when excited at a wavelength of 380 nm, the fluorescent probe (I) exhibits very weak fluorescence intensity at 527 nm. However, with Hg... 2 + As the concentration (0 μM–42 μM) increased, the fluorescence intensity of probe (I) at 527 nm gradually increased until it reached saturation. Figure 2 As shown. The maximum fluorescence emission intensity at 527 nm is selected as the ordinate, Hg 2+ Using different concentrations as the abscissa, linear fitting was performed to obtain two linear regression equations for different concentration ranges: y = 12.69473x + 41.66668 and y = 38.18359x - 513.65845. The results are as follows: Figure 3 As shown, the linear correlation coefficients R² are all greater than 0.99, and the fluorescent probe (I) and Hg... 2+ It exhibits a good linear relationship (e.g.) Figure 3 It has a minimum detection limit of 0.23 μM, exhibits good sensitivity, and can be used for the detection of Hg within a certain concentration range. 2+ Quantitative analysis and detection.

[0037] Example 4

[0038] Triphenylamine Schiff base fluorescent probe (I) for detecting Hg 2+ The robustness to interference from different potentially competing analytical objects. For example... Figure 4 As shown.

[0039] To verify the effect of probe (I) on Hg 2+ To further investigate the specificity of the probe (I) for identification, we also studied its resistance to interference from other potential analytes by adding Hg to the solution of probe (I). 2+ After adding 34 μM, the probe (I) solution showed a significant fluorescence enhancement at 527 nm. Subsequently, other metal ions (170 μM), containing Hg, were added. 2+The fluorescence intensity of the probe (I) solution did not change significantly, indicating that the presence of other potentially competing analytes does not interfere with the efficacy of probe (I) against Hg. 2+ The identification and detection of Hg, probe (I) for Hg 2+ It has good anti-interference capabilities.

[0040] Example 5

[0041] Triphenylamine Schiff base fluorescent probe (I) recognizes Hg 2+ The fluorescence response time.

[0042] To determine the detection of Hg 2+ The response time was measured, and the presence or absence of Hg in the DMSO:PBS (v / v = 1:1) solution of the fluorescent probe (I) was tested. 2+ Fluorescence changes over time, such as Figure 5 As shown. No Hg added. 2+ At the initial stage, the fluorescence intensity was very low, and the fluorescence intensity did not change over time; when Hg was added... 2+ Subsequently, the fluorescence intensity significantly increased within 1 second, and reached its maximum value within 2 seconds. After 2 seconds, the fluorescence intensity tended to stabilize, indicating that the fluorescent probe (I) has a short response time and high sensitivity, and can monitor Hg in real time. 2+ .

[0043] Example 6

[0044] Different pH values ​​affect the recognition of Hg by triphenylamine Schiff base fluorescent probe (I). 2+ Impact

[0045] In order to obtain Hg detection 2+ The optimal pH range was determined, and the fluorescence intensity of a 10 μM fluorescent probe (I) was tested within the pH range of 2–12. Figure 5 As shown, in the absence of Hg 2+ In DMSO:PBS (v / v = 1:1), when the pH range was 2-12, the fluorescence intensity of probe (I) showed no significant change. However, when Hg was added... 2+ After being heated to 34 μM, the fluorescence intensity of probe (I) significantly increased over a wide alkaline pH range (8-12), indicating that probe (I) has a wide pH applicability.

Claims

1. The use of a triphenylamine Schiff base fluorescent probe, characterized in that, Hg was carried out in a DMSO:PBS solution with a v / v ratio of 1:

1. 2+ The quantitative and qualitative detection of Hg, wherein the detection is fluorescence detection; the fluorescent probe is effective against Hg. 2+ It exhibits excellent detection performance, with a detection limit as low as 0.23 μM; The chemical structure of the triphenylamine Schiff base fluorescent probe is shown in formula (I):

2. The use of the triphenylamino Schiff base fluorescent probe according to claim 1, characterized in that, The triphenylamine Schiff base fluorescent probes were synthesized according to the following experimental steps: Using N,N-dimethylformamide as a solvent, 4-(diphenylamino)-2-hydroxybenzaldehyde (II) and 2-aminophenol were reacted via an intermolecular condensation reaction in the presence of p-toluenesulfonic acid to yield compound (I):

3. The use of the triphenylamino Schiff base fluorescent probe according to claim 2, characterized in that, 4-(diphenylamino)-2-hydroxybenzaldehyde (II), 2-aminophenol, and p-toluenesulfonic acid were dissolved in N,N-dimethylformamide and reacted at 70°C for 7 h under N2 protection to obtain compound (I).

4. The use of the triphenylamino Schiff base fluorescent probe according to claim 2, characterized in that, The molar ratio of 4-(diphenylamino)-2-hydroxybenzaldehyde (II) to 2-aminophenol is 1:1.

5.

5. The use of the triphenylamino Schiff base fluorescent probe according to claim 2, characterized in that, Under a nitrogen atmosphere, the reaction mixture was heated to 70°C and stirred for 7 hours to obtain compound (I).

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