A fluorescent probe based on 2-hydrazylpyridine-modified aminobenzophenoxazinone derivative and its application

Abstract

This invention discloses a fluorescent probe based on 2-hydrazylpyridine-modified aminobenzophenoxazinone derivative and its application. The invention is based on 2-hydrazylpyridine-modified aminobenzophenoxazinone derivative, abbreviated as CdP, with the structure shown below. This invention obtains an "on-off" fluorescent probe by modifying the aminobenzophenoxazinone derivative with 2-hydrazylpyridine. This probe can identify Cd in aqueous solutions and e-cigarette vapors. 2+ Furthermore, it exhibits significantly enhanced fluorescence intensity, making it a promising candidate for Cd-based electronic cigarette smoke compounds. 2+ Rapid detection of content provides a powerful tool.

Description

Technical Field

[0001] This invention belongs to the field of fluorescent materials, specifically relating to a fluorescent probe based on 2-hydrazylpyridine modified aminobenzophenoxazinone derivative and its application. Background Technology

[0002] Cadmium (Cd) is a heavy metal that is severely toxic to human health, causing kidney failure, calcium metabolism disorders, and increasing the incidence of various cancers. Therefore, rapid and efficient detection of Cd is crucial. 2+ It is of great significance for environmental monitoring and disease prevention.

[0003] A fluorescent probe is a chemical reagent that can detect specific molecules or ions by detecting changes in fluorescence signals. When excited by light of a specific wavelength, a fluorescent probe emits fluorescence of that specific wavelength, and changes in its intensity or wavelength can reflect the presence and concentration of the target ion.

[0004] In recent years, numerous fluorescent probes for cadmium ions have been reported and applied in various fields such as environmental monitoring and in vivo biological research. However, these probes may encounter some problems, such as low quantum yield and small Stokes shift. Aminobenzophenone-oxazinone derivative dyes have been chosen to improve the optical performance of probes and solve the problems of low quantum yield, small Stokes shift, and low fluorescence intensity due to their advantages such as good photostability, near-infrared emission wavelength, large Stokes shift, high quantum yield, and easy observation with the naked eye. Furthermore, the rigid structure of benzophenone-oxazinone allows for the specific binding of cadmium ions, resulting in a selectivity far superior to other existing probes. In summary, this invention provides a Cd... 2+ Fluorescent probes, with their high selectivity, sensitivity, and rapid response, have broad application prospects in environmental monitoring and biomedical research. Summary of the Invention

[0005] This invention provides a fluorescent probe based on 2-hydrazopyridine-modified aminobenzophenoxazinone derivatives and its application. This invention obtains an "off-on" fluorescent probe by modifying aminobenzophenoxazinone derivatives with 2-hydrazopyridine. This probe can identify Cd in aqueous solutions and e-cigarette vapors. 2+ Furthermore, it exhibits significantly enhanced fluorescence intensity, making it a promising candidate for Cd-based electronic cigarette smoke compounds. 2+ Rapid detection of content provides a powerful tool.

[0006] This invention relates to a fluorescent probe based on a 2-hydrazylpyridine-modified aminobenzophenoxazinone derivative, with the molecular formula C. 22 H 15 N5O2, abbreviated as CdP, has the following structure:

[0007] .

[0008] The method for preparing the fluorescent probe CdP of the present invention includes the following steps:

[0009] Step 1: 5.2 g (30 mmol) of 2-hydroxy-1,4-naphthoquinone and 4.6 g (30 mmol) of 2-hydroxy-4-nitroaniline were dissolved in an 80% aqueous acetic acid solution and stirred at 100 °C for 12 h. Most of the acetic acid was removed by rotary evaporation, and the remaining liquid was poured into water. The pH was adjusted to neutral with sodium bicarbonate, and the precipitate was collected by filtration. The precipitate was extracted with ethyl acetate and water, and the organic phase was collected and separated by silica gel column chromatography to obtain 6.54 g of compound 1 (yellow solid powder, yield 74.6%).

[0010] Step 2: Dissolve 2.92 g (10 mmol) of compound 1 in anhydrous ethanol, add 5.23 g (80 mmol) of zinc powder and 2 mL of dilute hydrochloric acid, reflux at 80 °C for 4 h, filter, collect the filtrate, and perform column chromatography with petroleum ether and ethyl acetate (1:1) as the mobile phase to obtain 2.28 g of compound 2 (black solid powder, yield 87.7%).

[0011] Step 3: 1.31 g (5 mmol) of compound 2 and 1.28 g (10 mmol) of dichloromethyl methyl ether were dissolved in dichloromethane and stirred at room temperature for 5 min. Then, 3.8 g (20 mmol) of titanium tetrachloride was added and the mixture was stirred for another 30 min. The reaction was quenched with ice water, and the organic phase was extracted with ethyl acetate and collected. Column chromatography was performed using petroleum ether and ethyl acetate (2:1) as the mobile phase to give 1.15 g of compound 3 (dark red solid powder, yield 79.3%).

[0012] Step 4: Dissolve 1.45 g (5 mmol) of compound 3 and 0.55 g (5 mmol) of 2-hydrazinopyridine in ethanol, add 0.5 mL of acetic acid, reflux and stir for 8 h, and filter to obtain 1.65 g of target product 4 (CdP, dark red solid powder, yield 86.6%).

[0013] The synthesis route is shown below:

[0014] .

[0015] The fluorescent probe CdP of this invention is used in the preparation of Cd 2+ Applications in testing reagents.

[0016] Furthermore, Cd 2+ When the concentration is in the equivalent range of 0.1-0.6 eq, the fluorescence intensity of the fluorescent probe at 610 nm is similar to that of Cd. 2+ The concentration showed a linear relationship, and the detection limit was 1.54 nM.

[0017] Recognition mechanism of fluorescent probe (CdP):

[0018] .

[0019] Compared with the prior art, the probe of the present invention has better selectivity. Due to the rigid structure of benzophenoxazinone, it can specifically bind cadmium ions. After binding, the solution changes from yellow to deep red and emits red fluorescence with a longer wavelength. The color change is more obvious under natural light than that of the prior art probe and is more obvious to the naked eye. It can be judged without the aid of instruments.

[0020] In addition, due to the existing Cd 2+ Fluorescent probes have limited detection capabilities for low concentrations of cadmium ions, while Cd in e-cigarette vapors is limited. 2+ At low concentrations, it is difficult to displace the Cd present. 2+ Zinc ions in the fluorescent probe show no significant fluorescence change. Therefore, existing Cd... 2+ Fluorescent probes cannot be used in Cd-containing e-cigarettes. 2+ The detection.

[0021] Compared with the prior art, the beneficial effects of the present invention are reflected in:

[0022] Due to the PET effect of 2-hydrazinopyridine, the fluorescence of the aminobenzophenoxazinone backbone of the probe CdP in this invention is in a closed state. After the reaction, due to Cd... 2+ The binding of this substance blocked the PET effect and the high quantum yield of the aminobenzophenoxazinone skeleton itself, resulting in a bright, visible color change and red fluorescence.

[0023] The CdP probe of this invention is yellow in solution before reaction and turns dark red after reaction. The phenomenon is obvious and can be observed with the naked eye. Its fluorescence is significantly enhanced at 610 nm, making it a "turn-on" probe.

[0024] The CdP probe of this invention can rapidly and specifically identify Cd in aqueous solutions and e-cigarette vapors. 2+ . Attached Figure Description

[0025] Figure 1 It is a fluorescent probe CdP and Cd 2+ Images taken under 365 nm ultraviolet light before and after the reaction. From Figure 1 As can be seen from this, CdP and Cd 2+ After the reaction, the fluorescence changed from a darker yellow fluorescence to a bright red fluorescence.

[0026] Figure 2 It is a fluorescent probe CdP (20 μM) and Cd 2+ (20 μM) UV spectrum after reaction. From Figure 2 As can be seen, the maximum absorption peak underwent a redshift after the reaction.

[0027] Figure 3 It is a fluorescent probe CdP and Cd 2+ Fluorescence intensity changes in the range of 475 nm to 725 nm after the reaction (0-18 μM). From... Figure 3 As can be seen from this, CdP and Cd 2+ The fluorescence emission gradient was enhanced after the reaction (0-18 μM).

[0028] Figure 4 It is a fluorescent probe CdP and Cd 2+ Linear fitting plot of relative fluorescence intensity at 610 nm after (0-20 μM) reaction. From Figure 4 As can be seen from this, CdP and Cd 2+ The relative fluorescence intensity after the reaction (0-20 μM) and C Cd 2+ / C CdP (The equivalent ratio of the two) has a good linear correlation.

[0029] Figure 5 This is a selectivity test result for the fluorescent probe CdP. From... Figure 5 As can be seen from this, CdP affects Cd 2+ It offers good selectivity.

[0030] Figure 6 This is a graph showing the interference of the fluorescent probe CdP. From... Figure 6 It can be seen from this that when Cd 2+ When coexisting with potentially interfering substances, CdP and Cd 2+ The reaction is unaffected. Detailed Implementation

[0031] The technical solution of the present invention will be further analyzed and explained through specific embodiments below.

[0032] Example 1: Preparation of CdP

[0033]

[0034] 1.45 g (5 mmol) of compound 3 and 0.55 g (5 mmol) of 2-hydrazinopyridine were dissolved in ethanol, 0.5 mL of acetic acid was added, and the mixture was refluxed and stirred for 8 h. After the reaction was stopped, the mixture was filtered to obtain 1.65 g of compound 4 (CdP, dark red solid powder, yield 86.6%). 1H NMR (600 MHz, Chloroform-d) δ 9.07 (s, 2H), 8.66 (d, J = 0.6 Hz,2H), 8.39 (dd, J = 4.3, 1.7 Hz, 2H), 8.14 (dd, J = 7.5, 1.3 Hz, 2H), 7.99(dd, J = 7.6, 1.3 Hz, 2H), 7.74 (td, J = 7.0, 1.5 Hz, 2H), 7.70 (s, 2H), 7.68(td, J = 7.6, 1.3 Hz, 2H), 7.53 (td, J = 7.8, 1.3 Hz, 2H), 7.37 (dd, J = 7.0,1.4 Hz, 2H), 7.14 – 7.09 (m, 2H), 6.95 (s, 2H), 6.49 (s, 2H), 6.08 (s, 4H).

[0035] Example 2: Spectral properties of CdP

[0036] First, a 1 mM CdP stock solution was prepared using dimethyl sulfoxide (DMSO), and then diluted to 20 μM with ethanol. The cadmium ion standard solution was obtained by dissolving cadmium chloride in deionized water. The absorption spectrum of CdP in the ethanol solution (20 μM) is approximately 463 nm. 2+ When (20 μM) was added to the probe solution, we found that in Cd 2+ After addition, the probe and Cd 2+ The reaction occurs immediately, accompanied by a change in solution color; the absorption peak at 463 nm shifts to blue at 520 nm. Figure 1 , Figure 2 )

[0037]

[0038] For quantitative analysis, we then recorded the probe (20 μM) and 0-20 μM d. 2+ Fluorescence intensity after reaction (Ex: 543 nm, Em = 610 nm) Figure 3 ), and it was found that the probe CdP was added to Cd 2+ The fluorescence intensity at 610 nm was then in the equivalent range of 0.1–0.6 eq, similar to that of Cd. 2+ The concentrations showed a linear relationship, and a standard curve was plotted. Figure 4 The detection limit of the probe was calculated to be as low as 1.54 nM, and the high accuracy and reliability of the measurement results were ensured through multiple calibrations and verifications.

[0039]

[0040] Next, we tested the probe with various common interfering ions and determined that the CdP probe has significant high selectivity and anti-interference ability for cadmium ions. Figure 5 , Figure 6 )

[0041] Subsequently, this invention uses a spiking method, by adding Cd to the e-liquid. 2+ The standard was used, and its concentration was expressed as the ratio (equivalent ratio) of its concentration to the detection probe CdP. The concentration gradient was set to 0.15, 0.25, 0.35, 0.45, and 0.55. The fluorescence intensity after the reaction with the fluorescent probe CdP in the optimized reaction system was measured using a fluorescence spectrophotometer. Based on the obtained linear fitting equation, the corresponding CdP concentration was calculated. 2+ Concentration. The results are shown in Table 3. The recovery rates ranged from 97.8% to 103.6%, indicating that CdP can accurately detect Cd in e-cigarette liquids within the concentration range of 0-0.6 equivalents. 2+ .

[0042]

Claims

1. A 2-hydrazylpyridine-modified aminobenzophenoxazinone derivative, abbreviated as CdP, characterized in that... Its structure is as follows: 。 2. The preparation method of the 2-hydrazylpyridine-modified aminobenzophenoxazinone derivative according to claim 1, characterized in that... Includes the following steps: Step 1: Dissolve 2-hydroxy-1,4-naphthoquinone and 2-hydroxy-4-nitroaniline in an aqueous acetic acid solution and stir the reaction at 100°C. After the reaction is complete, remove most of the acetic acid by rotary evaporation. Pour the remaining liquid into water, adjust the pH to neutral with sodium bicarbonate, filter and collect the precipitate, extract with ethyl acetate and water, collect the organic phase, and separate it with silica gel column to obtain compound 1. Step 2: Dissolve compound 1 in anhydrous ethanol, add zinc powder and dilute hydrochloric acid, react under reflux, filter after the reaction is complete, collect the filtrate, and separate compound 2 by column chromatography; Step 3: Dissolve compound 2 and dichloromethyl methyl ether in dichloromethane, stir at room temperature, then add titanium tetrachloride and continue stirring for 30 min. Quench the reaction with ice water, extract with ethyl acetate and collect the organic phase, and separate by column chromatography to obtain compound 3. Step 4: Dissolve compound 3 and 2-hydrazinopyridine in ethanol, add acetic acid, reflux and stir to react, and filter to obtain target product 4 after the reaction is complete; The synthesis route is shown below: 。 3. The method of preparing Cd based on 2-hydrazylpyridine-modified aminobenzophenoxazinone derivatives according to claim 1 2+ Applications in testing reagents.

4. The application according to claim 3, characterized in that: The detection reagent can specifically identify Cd in aqueous solutions and / or e-cigarette vapors. 2+ .

5. The application according to claim 4, characterized in that: In the detection system, Cd 2+ When the concentration is in the equivalent range of 0.1-0.6 eq, the fluorescence intensity of the detection reagent at 610 nm is similar to that of Cd. 2+ The concentration shows a linear relationship.

6. The application according to claim 5, characterized in that: The detection reagent for Cd 2+ The detection limit is 1.54 nM.

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