A benzoquinoline-based AIE fluorescent probe, preparation method and its application in Fe 3+ Application in detection

Abstract

The present invention provides a benzoquinoline-based AIE fluorescent probe, a preparation method thereof and a benzoquinoline-based AIE fluorescent probe in Fe 3+ The present invention relates to an application in detection, belonging to the technical field of fluorescent probe preparation and analytical chemistry; in the present invention, a benzoquinoline-based AIE fluorescent probe is first prepared, wherein the benzoquinoline-based benzoquinoline-based AIE fluorescent probe is a 4-phenyl-2-(4-hydroxyphenyl)benzoquinoline fluorescent probe modified by a dansyl group, and the fluorescent probe has obvious aggregation-induced emission enhancement (AIE) characteristics, which can avoid the limitation of the ACQ effect on the application of fluorescent materials; the fluorescent probe can detect Fe in an aqueous medium. 3+ Rapid, highly selective fluorescence response and quantitative analysis without interference from common metal cations.

Description

Technical Field

[0001] The present invention belongs to the technical field of fluorescent probe preparation and analytical chemistry, and specifically relates to a benzoquinoline-based AIE fluorescent probe, a preparation method and a method for preparing the same in Fe 3+ Application in detection. Background Art

[0002] Iron is the most abundant and widely used transition metal in biological systems, playing a vital role in oxygen uptake, oxygen metabolism, electron transfer and transcriptional regulation. In humans, the development of many serious diseases is associated with excessive Fe 3+ Related diseases include various cancers, hepatitis, hemochromatosis and organ dysfunction such as liver, heart and pancreas. 3+ It is also involved in neurodegenerative diseases such as Alzheimer's disease and Parkinson's disease. Therefore, a method is needed to neutralize Fe in the water environment and in cells. 3+ Conduct follow-up testing.

[0003] Currently, Fe 3+ The detection methods mainly include atomic absorption spectroscopy, electrochemical method, inductively coupled plasma mass spectrometry, spectrophotometry, etc., but these methods have the disadvantages of long detection time, use of toxic organic reagents, high cost, and cumbersome operation process. Fluorescence detection method has the advantages of high sensitivity and fast detection speed. Detection methods based on fluorescent probes have been developed and applied in various industries. However, fluorescent materials have aggregation-induced fluorescence quenching (ACQ) phenomenon in aqueous solution, which limits the application of fluorescent materials in aqueous media, especially in the field of cell imaging and ion monitoring in living bodies. The application is restricted to varying degrees. Aggregation-induced fluorescence enhancement (AIE) material is a fluorescent dye that can effectively overcome the limitations of traditional ACQ. Its fluorescence is very weak or even non-luminescent in dilute solution, but its fluorescence is greatly enhanced in the aggregated state. It can be used for the detection of ions in the environment, fluorescent labeling of living cells, fingerprint detection, tracking and monitoring of small molecules and anions and cations in living bodies, etc. However, there is currently no information on the preparation of benzoquinoline-based AIE fluorescent materials and their application in detecting Fe in water environment. 3+ Therefore, given the characteristics of AIE fluorescent materials, it is necessary to prepare new fluorescent probes with AIE properties to meet the needs of Fe 3+ testing needs. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the present invention provides a benzoquinoline-based AIE fluorescent probe, a preparation method and a method for preparing the same. 3+In the present invention, a benzoquinoline-based AIE fluorescent probe is first prepared. The benzoquinoline-based AIE fluorescent probe is a 4-phenyl-2-(4-hydroxyphenyl)benzoquinoline fluorescent probe modified with a dansyl group. The fluorescent probe has obvious aggregation-induced emission enhancement (AIE) characteristics and can avoid the limitation of the ACQ effect on the application of fluorescent materials. The fluorescent probe can detect Fe in aqueous medium. 3+ Rapid and highly selective fluorescence response without interference from common metal cations.

[0005] The present invention first provides a benzoquinoline-based AIE fluorescent probe, the chemical structure of which is:

[0006] The benzoquinoline-based AIE fluorescent probe is denoted as probe QPNS.

[0007] The present invention also provides a method for synthesizing the above-mentioned benzoquinoline-based AIE fluorescent probe, which specifically comprises the following steps:

[0008] 4-phenyl-2-(4-hydroxyphenyl)benzoquinoline, dansyl chloride, dichloromethane and triethylamine are mixed evenly and stirred for reaction. After the reaction, dichloromethane is evaporated to obtain a solid, which is washed, filtered and dried to obtain a benzoquinoline-based AIE fluorescent probe.

[0009] Preferably, the chemical structural formula of the 4-phenyl-2-(4-hydroxyphenyl)benzoquinoline is

[0010]

[0011] Preferably, the molar ratio of the 4-phenyl-2-(4-hydroxyphenyl)benzoquinoline, dansyl chloride and triethylamine is 1 mmol: 0.8-1.5 mmol: 2-5 mmol.

[0012] Preferably, the usage ratio of the 4-phenyl-2-(4-hydroxyphenyl)benzoquinoline and dichloromethane is 1 mmol:15-25 mL.

[0013] Preferably, the stirring reaction is carried out at room temperature for 18 to 30 hours.

[0014] Preferably, the washing conditions are: washing with an ethanol-water mixed solvent and then washing with cold ethanol.

[0015] The present invention also provides the above-mentioned benzoquinoline-based AIE fluorescent probe for quantitative detection of Fe 3+ Application in.

[0016] Preferably, the application is the quantitative detection of Fe in aqueous media 3+ .

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] (1) The benzoquinoline-based fluorescent probe (QPNS) prepared by the present invention has two freely rotatable phenyl and dansyl derivatives at positions 2 and 4 of the luminescent group (benzoquinoline). In solution, the probe exhibits almost no fluorescence emission due to the non-radiative energy loss caused by the rotation of these two groups. When the probe molecules are in an aggregated state, the rotation of the intramolecular groups is restricted, resulting in a reduction in non-radiative energy loss, an increase in the fluorescence quantum yield, and bright enhanced fluorescence emission (AIE). This invention provides a simple design strategy and preparation method for the design and synthesis of new benzoquinoline-based AIE fluorescent materials.

[0019] (2) The benzoquinoline fluorescent probe QPNS of the present invention can be used to detect Fe in aqueous media 3+ , showing good optical responsiveness. In the highly aqueous DMSO / H20 test system, the selective experimental results of 19 common metal ions showed that the probe was only sensitive to Fe 3+ It has obvious fluorescence response. 3+ The fluorescence titration results showed that as Fe 3 + With the increase of the concentration of Fe 3+ The concentration of Ag(10-100μM) showed a good linear relationship. + 、Fe 2+ Cr 3+ and Hg 2+ The addition of 18 common metals such as Fe 3+ There were no noticeable disturbances. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is the synthetic route of the benzoquinoline-based AIE fluorescent probe QPNS described in the present invention.

[0021] Figure 2 Fluorescence spectra of benzoquinoline-based AIE fluorescent probe in DMSO-H2O test systems with different water content ratios.

[0022] Figure 3 This is a graph showing the relationship between the fluorescence intensity of the probe QPNS (5.0 μM) at 510 nm and the water content.

[0023] Figure 4 This is a diagram showing the selectivity of probe QPNS (5.0 μM) for different metal ions.

[0024] Figure 5 For the probe QPNS and excess Fe 3+ The relationship between the fluorescence intensity of the system at 510 nm and time.

[0025] Figure 6 The fluorescence intensity of the probe QPNS changes with Fe 3+ Fluorescence emission spectra of the concentration changes.

[0026] Figure 7 The fluorescence intensity of the probe QPNS at 510 nm is related to the Fe 3+ Linear relationship plot in the concentration range of 10-100 μM.

[0027] Figure 8 For the probe QPNS and excess Fe 3+ The fluorescence intensity bar graph at 510 nm after adding other metal cations to the system. DETAILED DESCRIPTION

[0028] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but the protection scope of the present invention is not limited thereto.

[0029] Example 1:

[0030] The synthetic route of the benzoquinoline-based AIE fluorescent probe of the present invention is as follows: Figure 1 As shown, the specific process is as follows: 4-phenyl-2-(4-hydroxyphenyl)benzoquinoline (0.347 g, 1 mmol) and dansyl chloride (0.270 g, 1 mmol) are added to a flask containing 20 mL of dichloromethane, mixed evenly, and then 500 μL of triethylamine is added to the above solution. The mixture is stirred at room temperature in a flask equipped with a condenser for 24 hours, and TLC tracking is performed until the reaction is completed. The dichloromethane is evaporated to obtain a crude product, and the crude product is washed with an ethanol-water mixed solvent 3 times (5 mL / time), washed with cold ethanol 3 times (5 mL / time), and dried to obtain 0.394 g of a benzoquinoline-based AIE fluorescent probe with a yield of 68%.

[0031] The synthesis method of 4-phenyl-2-(4-hydroxyphenyl)benzoquinoline was based on the literature (X. Zhang, Xuefeng Xu, Lintao Yu, Qiang Zhao, Bronsted acid-mediated reactions of aldehydes with 2-vinylaniline and biphenyl-2-amine, Tetrahedron Lett., 55 (2014) 2280–2282.)

[0032] In this example, the product was characterized.1 H NMR (600MHz, CDCl3) δ (ppm): 8.58 (d, J = 8.5Hz, 1H), 8.53 (d, J = 8.6Hz, 1H), 8.08 (dd,J=7.3,1.3Hz,1H),8.02(dd,J=9.5,7.8Hz,3H),7.94(d,J=9.0Hz,1H),7.83 (d,J=7.8Hz,1H),7.71–7.67(m,1H),7.65–7.61(m,2H),7.52–7.48(m,3H),7.4 7–7.36(m,4H),7.26–7.24(m,1H),7.13(m,1H),7.06–7.01(m,2H),2.90(s,6H). 13 C NMR (151 MHz, CDCl3) δ (ppm): 153.85, 151.96, 150.59, 149.70, 149.31, 142.76, 137.80, 132.92, 132.05, 131.69, 131.44, 130.84, 129.24, 129.07, 128.86, 128.62, 128.59, 128.26, 128.21, 128.03, 126.60, 125.62, 122.99, 122.41, 121.54, 119.49, 115.65, 45.44. This indicates that the benzoquinoline-based AIE fluorescent probe was successfully synthesized.

[0033] Example 2:

[0034] The synthetic route of the benzoquinoline-based AIE fluorescent probe of the present invention is as follows: Figure 1 As shown, the specific process is as follows: 4-phenyl-2-(4-hydroxyphenyl)benzoquinoline (0.347 g, 1 mmol) and dansyl chloride 2 (0.215 g, 0.8 mmol) are added to a flask containing 15 mL of dichloromethane, mixed evenly, and then 276 μL of triethylamine is added to the above solution. The mixture is stirred at room temperature in a flask equipped with a condenser for 18 hours, and TLC tracking is performed until the reaction is completed. Dichloromethane is evaporated to obtain a crude product, and the crude product is washed with an ethanol-water mixed solvent 3 times (5 mL / time), washed with cold ethanol 3 times (5 mL / time), and dried to obtain a benzoquinoline-based AIE fluorescent probe.

[0035] Example 3:

[0036] The synthetic route of the benzoquinoline-based AIE fluorescent probe of the present invention is as follows: Figure 1As shown, the specific process is as follows: 4-phenyl-2-(4-hydroxyphenyl)benzoquinoline (0.347 g, 1 mmol) and dansyl chloride 2 (0.403 g, 1.5 mmol) are added to a flask containing 25 mL of dichloromethane, mixed evenly, and then 691 μL of triethylamine is added to the above solution. The mixture is stirred at room temperature in a flask equipped with a condenser for 30 hours, and TLC tracking detection is performed until the reaction is completed. The dichloromethane is evaporated to obtain a crude product, and the crude product is washed with an ethanol-water mixed solvent 3 times (5 mL / time), washed with cold ethanol 3 times (5 mL / time), and dried to obtain a benzoquinoline-based AIE fluorescent probe.

[0037] Example 4:

[0038] In this example, the AIE performance of the benzoquinoline-based AIE fluorescent probe prepared in Example 1 was investigated. The specific investigation method and results are shown below.

[0039] Preparation of probe stock solution: Accurately weigh 29.0 mg of probe QPNS and place it in a 50 mL volumetric flask. Dose the flask with DMSO to obtain a probe stock solution with a concentration of 1.0 mM.

[0040] (1) AIE performance of probe QPNS:

[0041] Add 15 μL of probe stock solution to each of 10 stoppered test tubes, and then add 3 mL of DMSO-H2O (V / V) mixed solvents with different water content ratios to increase the water content in the 10 stoppered test tubes from 0% to 90%. Then mix the probe stock solution and DMSO-H2O mixed solvent to obtain the test solution. Use 368 nm as the excitation wavelength to measure the fluorescence spectrum of each test solution. The measurement results are as follows: Figure 2 and 3 shown.

[0042] Figure 2 The fluorescence spectra of benzoquinoline-based AIE fluorescent probe in DMSO-H2O test systems with different water content ratios are shown in Figure 2. Figure 3 The graph shows the relationship between the fluorescence intensity of the probe QPNS (5.0 μM) at 510 nm and the water content. Figure 2 and Figure 3 As can be seen, QPNS exhibits two very weak fluorescence emission peaks at 414nm and 534nm in pure DMSO. The intensities of these two emission peaks gradually decrease with increasing water content (fw ≤ 30%). When fw = 50%, the fluorescent probe QPNS exhibits a significantly enhanced fluorescence emission peak at 510nm, indicating a significant AIE effect. When fw increases from 60% to 90%, the fluorescence intensity of the fluorescent probe decreases slightly due to precipitation.

[0043] Therefore, the benzoquinoline-based AIE fluorescent probe described in this embodiment has obvious AIE properties and can be used as an AIE fluorescent material.

[0044] Example 5:

[0045] 750 μL of the probe QPNS stock solution was placed in a 150 mL volumetric flask, 29.25 mL of dimethyl sulfoxide was added, and the volume was adjusted with ultrapure water to obtain a probe QPNS test solution with a concentration of 5.0 μM.

[0046] (1) Investigation of the ion selectivity of the probe QPNS:

[0047] Take 3mL of the above probe QPNS test solution and place it in a four-way cuvette, then add 15μL of 10mM common metal Ag + 、Fe 2+ 、Li + Cr 3+ , K + Mg 2+ , Ca 2+ 、Na + 、Ni 2+ 、Cu + 、Cu 2+ 、Cd 2+ 、Co 2+ 、Ni + , Pb 2+ 、Zn 2 + 、Fe 3+ 、Hg 2+ and Al 3+ Nitrate or chloride water solution is used to obtain test solutions containing various metal ions. The fluorescence emission spectra of various test solutions are tested, and the test results are as follows: Figure 4 shown.

[0048] Figure 4 The selectivity of probe QPNS (5.0 μM) to different metal ions is shown in the figure. It can be seen from the figure that only Fe 3+ The addition of Fe ions significantly reduced the fluorescence intensity of the probe QPNS at 510 nm, while other metal ions had little effect on the fluorescence intensity of the probe QPNS. 3+ The detection has good selectivity.

[0049] (2) Probe QPNS for Fe 3+ Response dynamics testing:

[0050] Take 3mL of probe QPNS (5.0μM) in a cuvette and add excess Fe 3+, test the fluorescence emission spectrum for a total of 1200 seconds, the test results are as follows Figure 5 shown. Figure 5 Containing probe QPNS and excess Fe 3+ The fluorescence intensity change diagram of the system shows that the fluorescence emission intensity of the probe QPNS at a wavelength of 510 nm decreases rapidly and then changes slowly, which indicates that the probe QPNS has a strong effect on Fe 3+ The response was quick.

[0051] Example 6:

[0052] Take 15 μL of probe QPNS mother solution, 585 μL of dimethyl sulfoxide solution and 2400 μL of ultrapure water and place them in a four-way cuvette, then add 3 μL of 10 mM Fe 3+ After mixing the solution evenly, wait for 3 minutes and test the fluorescence spectrum of the test solution. The fluorescence titration experiment results are as follows: Figure 6 and Figure 7 shown.

[0053] Figure 6 The fluorescence intensity of the probe QPNS changes with Fe 3+ Fluorescence emission spectra of concentration changes, Figure 7 is the fluorescence intensity of the probe QPNS at 510 nm and Fe 3+ The linear relationship diagram of Fe 3+ As the concentration of Fe increases, the fluorescence intensity of the probe QPNS gradually decreases, and the fluorescence intensity at 510 nm is similar to that of Fe 3+ The concentration of β-catenin was linear (R 2 =0.9509), and the detection limit formula LOD = 3σ / K was used to calculate the detection limit of QPNS probe for Fe in the DMSO / H2O (2 / 8, v / v) test system. 3+ The lowest detection limit was 0.81 μM.

[0054] Example 7:

[0055] 3 mL of 5.0 μM probe QPNS and 15 μL of 10 mM Fe 3+ Place in a stoppered test tube, and then add 15 μL of 10 mM Ag + 、Fe 2+ 、Li + Cr 3+ , K + Mg 2+ , Ca 2+ 、Na + 、Ni 2+ 、Cu + 、Cu 2+ 、Cd2+ 、Co 2+ 、Ni + , Pb 2+ 、Zn 2+ 、Fe 3+ 、Hg 2+ and Al 3+ Nitrate or chloride aqueous solution, respectively, to obtain the test solution containing various metal cation interference. Test the fluorescence emission spectrum of the test solution containing various metal cation interferences, the test results are as follows Figure 8 shown.

[0056] Figure 8 For the presence of probe QPNS and excess Fe 3+ The fluorescence intensity of the system after adding other metal cations is shown in the figure. It can be seen from the figure that the addition of other metal cations has almost no effect on the fluorescence intensity of the solution at 510nm, indicating that the probe QPNS has a strong effect on Fe 3+ The tested one has good anti-interference ability.

[0057] In summary, the benzoquinoline-based AIE fluorescent probe of the present invention has obvious aggregation-induced emission enhancement (AIE) characteristics, which can avoid the limitation of the ACQ effect on the application of fluorescent materials; the fluorescent probe can be used to detect Fe in aqueous medium. 3+ Rapid, highly selective fluorescence response and quantitative analysis without interference from common metal cations.

[0058] The embodiments described are preferred implementations of the present invention, but the present invention is not limited to the above implementations. Any obvious improvements, substitutions or modifications that can be made by those skilled in the art without departing from the essence of the present invention are within the scope of protection of the present invention.

Claims

1. A benzoquinoline-based AIE fluorescent probe, characterized in that The chemical structural formula of the benzoquinoline-based AIE fluorescent probe is:

2. The method for synthesizing the benzoquinoline-based AIE fluorescent probe according to claim 1, wherein: include: 4-phenyl-2-(4-hydroxyphenyl)benzoquinoline, dansyl chloride, dichloromethane and triethylamine were mixed evenly and stirred for reaction. After the reaction, dichloromethane was evaporated to obtain a solid, which was washed, filtered and dried to obtain a benzoquinoline-based AIE fluorescent probe. The chemical structural formula of the 4-phenyl-2-(4-hydroxyphenyl)benzoquinoline is The molar ratio of 4-phenyl-2-(4-hydroxyphenyl)benzoquinoline, dansyl chloride and triethylamine is 1 mmol: 0.8-1.5 mmol: 2-5 mmol; The ratio of 4-phenyl-2-(4-hydroxyphenyl)benzoquinoline to dichloromethane is 1 mmol: 15-25 mL; The stirring reaction is carried out at room temperature for 18 to 30 hours.

3. The benzoquinoline-based AIE fluorescent probe according to claim 1 is used for quantitative detection of Fe for non-therapeutic and diagnostic purposes 3+ The application is the quantitative detection of Fe in aqueous medium 3+ .

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