Preparation method and application of quinolinyl imidazole boron trifluoride fluorescent probe

Abstract

This invention discloses a quinolinyl imidazole boron trifluoride fluorescent probe. The fluorescent probe is a quinolinyl imidazole compound synthesized by the Debus-Radziszewski imidazole synthesis method using 8-(2-(2-(2-methoxyethoxy))ethoxy)ethoxy)quinoline-2-carboxaldehyde, benzoyl, and aniline. Its chemical structure is shown in formula (I). The fluorescent probe of this invention exhibits specific selectivity for BF3 in acetonitrile solvent, extremely high sensitivity, and strong resistance to interference from other potential competing analytes, with a detection limit as low as 23.7 nM. This invention provides a simple and sensitive fluorescent probe for detecting BF3, with broad application prospects.

Description

Technical Field

[0001] This invention belongs to the fields of organic compound synthesis, fluorescent probes and fine chemical technology, and specifically relates to a quinolinyl imidazole BF3 fluorescent probe. Background Technology

[0002] Boron halides are widely used in industrial and laboratory research as boron donors for organoboron and inorganic boron compounds and as catalysts in organic synthesis. Among them, boron trifluoride (BF3), due to its electron-withdrawing properties, is often used as a Lewis acid catalyst and has been widely applied in various organic chemical reactions such as cationic polymerization, isomerization, (cyclic) condensation, etherification, N-benzylation, and Friedel-Crafts acylation. Despite its widespread use, BF3's corrosiveness and toxicity mean that even minor leaks can lead to environmental pollution and biological hazards. Therefore, developing ratiometric fluorescence sensing technology for identifying, detecting, and quantifying the absorbance of boron halides is crucial. Furthermore, due to its high reactivity, BF3 can react with materials such as metals and organic matter. Exposure to water or humid environments can cause explosions and release hydrogen gas, which can cause severe irritation to the respiratory tract, eyes, and skin, and even death. Therefore, the need for useful and reliable BF3 leak detection methods during production, storage, transportation, use, and waste disposal is particularly urgent.

[0003] Currently, various methods have been developed for identifying and detecting BF3, such as Fourier transform infrared spectroscopy, quartz microbalances, mixed-medium structure thin films, and electrochemical techniques. However, these methods are expensive, slow, energy-intensive, have high detection limits, and low sensitivity. In practical applications, they require large equipment and sample pretreatment, making them unsuitable for on-site detection of such highly toxic substances and unable to provide quantitative detection. Fluorescence methods offer advantages such as rapid detection, simple operation, low cost, high selectivity, and real-time monitoring, making them a powerful tool for detecting trace analytes and imaging. In recent years, compared to other volatile toxic gases such as carbon monoxide, sulfur dioxide, hydrazine, phosgene, and hydrogen sulfide, only a few reports have used common fluorophores such as rhodamine, Schiff bases, coumarin, and benzothiazole derivatives to detect BF3. Most chemical sensor probes suffer from drawbacks such as long response times, high detection limits, irreversible responses, and fluorescence quenching.

[0004] Based on the above considerations, this invention prepares a novel quinolinylimidazolium fluorescent probe that can specifically recognize BF3, exhibiting a significant change in fluorescence intensity after interaction with BF3, and possessing a low detection limit. This probe can also be applied to the selective and sensitive detection of gas-phase BF3. Due to its advantages of fast response speed, high selectivity, and high sensitivity, this probe has great application potential. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention synthesizes a quinolinyl imidazole BF3 fluorescent probe with good selectivity, strong anti-interference ability, short response time, and low detection limit through molecular design.

[0006] The present invention also provides a method for preparing the above-mentioned quinolinyl imidazole BF3 fluorescent probe.

[0007] The present invention also provides applications of the above-mentioned quinolinyl imidazole BF3 fluorescent probe.

[0008] Technical Solution: To achieve the above-mentioned objectives, the technical solution of this invention is: a quinolinyl imidazolium BF3 fluorescent probe, the chemical structure of which is shown in formula (I):

[0009]

[0010] The above-mentioned method for synthesizing quinolinyl imidazole BF3 fluorescent probes is characterized by the fact that it is synthesized according to the following experimental steps;

[0011] Compound (I) was obtained by reacting benzoyl with 8-(2-(2-(2-methoxyethoxy))ethoxy)ethoxy)quinoline-2-carboxaldehyde (II) and benzoyl with aniline via the Debus-Radziszewski imidazole synthesis method.

[0012] The specific synthetic route of the above-mentioned quinolinyl imidazole BF3 fluorescent probe is as follows:

[0013]

[0014] The steps are carried out by the following method: 8-(2-(2-(2-methoxyethoxy))ethoxy)ethoxy)quinoline-2-carboxaldehyde (II), benzoyl, aniline and ammonium acetate are dissolved in acetic acid, and the mixture is heated to 110°C and stirred for 12 hours under light-protected conditions to obtain compound (I);

[0015] The quinolinyl imidazole fluorescent probe of the present invention exhibits a unique fluorescence response to BF3 in an acetonitrile environment.

[0016] An acetonitrile solution of the fluorescent probe (I) was prepared, and then quantitative amounts of potential competing analytes, including phenylboronic acid, 2-fluoro-5-nitrobenzoic acid, trifluoroacetic acid, acetic acid, sodium borohydride, sodium fluoroborate, tetrabutylammonium fluoride, oxalic acid, pinacol diboronate, boric acid, and boron trioxide, were added. The selective recognition of the potential competing analytes was studied by fluorescence spectroscopy. The results are as follows: Figure 1As shown, the fluorescence emission intensity changes revealed that the fluorescent probe (I) of this invention exhibits a unique fluorescence response to BF3. Upon interaction with BF3, the fluorescence undergoes a significant red shift. In contrast, the spectral changes of other analytes under the same conditions are negligible, indicating that the probe has high selectivity for BF3. Furthermore, when a certain amount of the fluorescent probe solution was taken and BF3 was gradually added to 40 μM, the fluorescence intensity of the fluorescent probe (I) gradually decreased at 427 nm, while the fluorescence intensity gradually increased at 499 nm. The results are as follows. Figure 2 As shown. During the addition of BF3, the fluorescence intensity ratio (F) of the fluorescent probe (I) was selected. 499nm / F 427nm Using y = 0.1543x + 0.0919 and BF3 concentration as the x-axis, a linear regression was performed, yielding two linear regression curves: y = 0.1543x + 0.0919 and y = 1.1111x - 7.0952. The results are as follows: Figure 3 As shown, the linear correlation is high; therefore, this fluorescent probe can be used for the quantitative analysis and detection of boron trifluoride.

[0017] The quinolinylimidazolium-based BF3 fluorescent probe described in this invention exhibits superior resistance to interference from various potential competing analytes when detecting BF3, as shown in the following results. Figure 4 As shown, the fluorescence intensity of the fluorescent probe (I) hardly changed when other analytes were added, which confirms that the fluorescent probe (I) of the present invention has unique fluorescence selectivity for BF3 in acetonitrile and strong resistance to interference from other analytes.

[0018] The quinolinyl imidazole BF3 fluorescent probe described in this invention has the characteristic of short response time, such as... Figure 5 As shown, in the presence of boron trifluoride, the fluorescence intensity of the probe reaches saturation after 30 s. This ultrafast response probe can be used for real-time detection of BF3, indicating that the probe has high sensitivity.

[0019] The quinolinylimidazolium-based BF3 fluorescent probe described in this invention can sensitively, rapidly, and selectively detect gaseous BF3. After exposure to different amounts of BF3 (0-30%) CH3CN solution for 10 minutes, the fluorescence emission color of the test paper containing probe (I) changes from blue to green. For example... Figure 6 As shown. Furthermore, the fluorescence color changed drastically when the test strip was exposed to BF3 vapor. However, other volatile organic compounds (ethyl ether, cyclohexane, chloroform, ethyl acetate, boron trifluoride, toluene, n-butanol, acetonitrile, ethylene glycol, tetrahydrofuran, and isopropanol) did not cause significant changes in the fluorescence color of the test strip, such as... Figure 7 As shown, this indicates that the probe can be used as a portable, highly sensitive chemical sensor for on-site detection of gaseous BF3.

[0020] The beneficial effects of the present invention are: (1) the synthesis route of the fluorescent probe is simple, the reaction conditions are mild, and the purification method is convenient; (2) the fluorescent probe has good selectivity, strong anti-interference ability, high sensitivity, and a detection limit as low as 23.7 nM, and has broad application prospects in the fields of analytical chemistry and environmental detection. Attached Figure Description

[0021] Figure 1 The concentration of fluorescent probe (I) is 1×10 -5 Fluorescence intensity diagram of M after adding 8 equivalents of a potential competing analyte to an acetonitrile solution;

[0022] Figure 2 The concentration of fluorescent probe (I) is 1×10 -5 A fluorescence titration diagram of BF3 was performed in an acetonitrile solution of M. The vertical axis represents fluorescence emission intensity, and the horizontal axis represents emission wavelength. The excitation wavelength was 425 nm.

[0023] Figure 3 The fluorescent probe (I) uses the ratio of ion concentration at different equivalents of BF3 as the x-axis to fluorescence intensity (F). 499nm / F 427nm The vertical axis represents the linear fit; the horizontal axis represents the concentration of BF3 added, in units of 10⁻⁶. -6 M;

[0024] Figure 4 The concentration of fluorescent probe (I) is 1×10 -5 A bar chart showing the change in fluorescence intensity ratio after adding 8 equivalents of other competing analytes to an acetonitrile solution in which M and 4 equivalents of BF3 coexist.

[0025] Figure 5 The concentration of fluorescent probe (I) is 1×10 -5 Fluorescence changes of M in acetonitrile with and without BF3 over time;

[0026] Figure 6 This is a fluorescence effect image of a test strip loaded with fluorescent probe (I) exposed to gaseous boron trifluoride in a boron trifluoride solution (0-30%) under 365nm ultraviolet light;

[0027] Figure 7 This is a fluorescence effect diagram of a test strip loaded with fluorescent probe (I) exposed to different volatile organic compounds (VOCs) under 365nm ultraviolet light. Detailed Implementation

[0028] The present invention will now be described in further detail with reference to the embodiments and accompanying drawings.

[0029] Example 1

[0030] Preparation of quinolinylimidazolium trifluoride fluorescent probe (I).

[0031] 8-(2-(2-(2-methoxyethoxy))ethoxy)ethoxy)quinoline-2-carboxaldehyde (II) (0.32 mmol), benzoyl (0.47 mmol), aniline (0.47 mmol), ammonium acetate (1.6 mmol), and acetic acid (1.6 mL) were sequentially added to a round-bottom flask. The mixture was heated to 110 °C and stirred for 12 h under light-protected conditions. After the reaction was complete, the mixture was cooled to room temperature, and the reaction solution was poured into 100 mL of deionized water, resulting in the precipitation of organic solids. The residue was filtered and purified by silica gel column chromatography (eluent: ethyl acetate) to give a brownish-yellow viscous liquid (I) in 64% yield. 1 H NMR (400MHz, CDCl3, ppm) δ8.3 (d, J=8Hz, 1H), 8.2 (d, J=8Hz, 1H), 7.7 (d, J=7.2Hz, 2H), 7.4 (d, J=0.8Hz, 2H), 7.3 (d, J=4Hz, 7H), 7.2 (d, J=10.8H z, 4H), 7.2 (d, J = 6.8Hz, 2H), 7.0 (s, 1H), 4.1 (d, J = 4.8Hz, 2H), 3.8 (t, J = 4.8Hz, 2H), 3.7 (s, 2H), 3.7 (s, 2H), 3.7 (s, 2H), 3.6 (s, 2H), 3.4 (s, 3H)

[0032] Example 2

[0033] Selectivity study of quinolinyl imidazole fluorescent probes (I) against different potential competing analytes.

[0034] Prepare a precise acetonitrile solution of the 10 μM fluorescent probe (I). Figure 1As shown, the fluorescent probe (I) solution exhibits a distinct fluorescence emission spectrum at 427 nm. When eight equivalents of different potential competing analytes ((1) phenylboronic acid, (2) 2-fluoro-5-nitrobenzoic acid, (3) trifluoroacetic acid, (4) acetic acid, (5) sodium borohydride, (6) sodium fluoroborate, (7) tetrabutylammonium fluoride, (8) oxalic acid, (9) pinacol diboronate, (10) boric acid, and (11) boron trioxide) were added to the test solution containing the fluorescent probe (I), it was found that only after adding BF3 did the fluorescence intensity of the fluorescent probe (I) at 427 nm decrease, while the emission peak intensity at 499 nm showed a significant increase. Other potential competing analytes had almost no significant effect on the fluorescence spectrum of the probe (I). These results indicate that the fluorescent probe (I) has a high selective response to BF3. The above results indicate that the fluorescent probe (I) has excellent specific recognition ability for BF3 in complex analyte environments and can be used as a specific fluorescent probe for detecting BF3.

[0035] Example 3

[0036] Graph showing the change in fluorescence intensity of quinolinyl imidazole fluorescent probe (I) with increasing BF3 concentration.

[0037] The linear relationship between the fluorescence intensity of the fluorescent probe (I) and the concentration of BF3 was further investigated through titration experiments. Fluorescent titration of BF3 was performed in a 10 μM acetonitrile solution of the fluorescent probe (I), as follows: Figure 2 As shown, in the absence of BF3, the fluorescent probe (I) exhibits significant fluorescence intensity at 427 nm under 425 nm excitation. However, with increasing BF3 concentration (0-40 μM), the fluorescence intensity of probe (I) at 427 nm gradually decreases, while the emission peak intensity at 499 nm shows a significant increase. The fluorescent probe (I) shows a good linear relationship with BF3. Figure 3 The detection limit was 23.7 nM. These results indicate that probe (I) exhibits high selectivity and sensitivity for BF3 detection, making it feasible for real-world applications.

[0038] Example 4

[0039] The quinolinyl imidazole fluorescent probe (I) demonstrates resistance to interference from various potential competing analytes when detecting BF3.

[0040] To verify the specific recognition of BF3 by probe (I), we also investigated the anti-interference characteristics of probe (I) against other related analytes, and the results are as follows: Figure 4As shown, when BF3 was added to the solution of probe (I), a significant fluorescence enhancement was observed in the test solution at 499 nm. Subsequently, the addition of other analytes besides BF3 did not result in a significant change in the fluorescence intensity of the probe (I) solution. This indicates that the presence of other potential competing analytes does not interfere with the recognition and detection of BF3 by probe (I), and probe (I) exhibits good anti-interference capability for BF3 recognition.

[0041] Example 5

[0042] The fluorescence response time of the quinolinyl imidazole fluorescent probe (I) to recognize BF3.

[0043] To determine the response time for detecting BF3, the fluorescence changes of 10 μM fluorescent probe (I) in acetonitrile with and without BF3 were tested. The results are as follows: Figure 5 As shown, when BF3 (40 μM) is added, the fluorescent probe (I) in F 499nm / F 427nm The fluorescence intensity at the point increases instantaneously and reaches saturation and stabilizes after 30 seconds, indicating that probe (I) has high sensitivity to recognize BF3 and a short response time, and can be used as a fluorescent probe for real-time detection of BF3.

[0044] Example 6

[0045] Application of quinolinyl imidazole fluorescent probe (I) in the detection of gaseous BF3.

[0046] Prepare an accurate ethanol solution of 1 mM fluorescent probe (I). Immerse the test paper in the above solution and dry at room temperature. Figure 6 As shown, before exposure to BF3 vapor, the test paper containing probe (I) exhibited bright blue fluorescence. After exposure to different amounts of BF3 (0-30%) CH3CN solution for 10 minutes, the fluorescence emission color of the test paper containing probe (I) changed from blue to green. In addition, the selectivity of the test paper for BF3 and other volatile organic compounds was evaluated, including (1) diethyl ether, (2) cyclohexane, (3) chloroform, (4) ethyl acetate, (5) boron trifluoride, (6) toluene, (7) n-butanol, (8) acetonitrile, (9) ethylene glycol, (10) tetrahydrofuran, and (11) isopropanol. Figure 7 As shown, the fluorescence color changed significantly when the test strip was exposed to BF3 vapor. However, other volatile organic compounds did not cause significant changes in fluorescence. These results demonstrate that a rapid, portable solid-state platform can be prepared using probe (I) for the sensitive, rapid, and selective detection of gaseous BF3.

Claims

1. A quinolinylimidazolium-based BF3 fluorescent probe, characterized in that, Its chemical structural formula is shown in formula (I):

2. The method for synthesizing the quinolinylimidazolium-based BF3 fluorescent probe according to claim 1, characterized in that, It was synthesized according to the following experimental steps; Compound (I) was synthesized by the Debus-Radziszewski imidazole method using benzoyl and 8-(2-(2-(2-methoxyethoxy))ethoxy)ethoxy)quinoline-2-carboxaldehyde (II), with the following structural formula:

3. The method for preparing quinolinyl imidazole BF3 fluorescent probes according to claim 2, characterized in that, 8-(2-(2-(2-methoxyethoxy))ethoxy)ethoxy)quinoline-2-carboxaldehyde (II), benzoyl, aniline and ammonium acetate were dissolved in acetic acid and heated and stirred at 110°C in the dark for 12 h to obtain compound (I).

4. The method for preparing the quinolinyl imidazolium-based BF3 fluorescent probe according to claim 3, characterized in that, The molar ratio of 8-(2-(2-(2-methoxyethoxy))ethoxy)ethoxy)quinoline-2-carboxaldehyde(II) to benzoyl and aniline is 1:1.5:1.

5.

5. The method for preparing the quinolinyl imidazole BF3 fluorescent probe according to claim 2, characterized in that, The steps are carried out by the following method: under light-protected conditions, the reaction mixture is heated to 110°C and stirred for 12 hours to obtain compound (I).

6. The application of the compound of formula (1) of claim 1 as a BF3 fluorescent probe, characterized in that, The quantitative and qualitative detection of BF3 can be performed in acetonitrile. The detection method is fluorescence detection, and this application is not intended for the diagnosis or treatment of diseases.

Images