A copper ion ratio fluorescent probe and its preparation and application

Abstract

The present invention relates to a copper ion ratio fluorescent probe and its preparation and application. The fluorescent probe has a molecular formula of C 24 H 19 IN 2 O 2 The preparation of the fluorescent probe comprises the following steps: (1) reacting 4-methylquinoline with iodomethane to obtain 1,4-dimethylquinoline iodide, i.e., compound 3; (2) reacting compound 3 with 4-hydroxybenzaldehyde to obtain 4-(4-hydroxyphenylvinyl)-1-methylquinoline iodide, i.e., compound 2; (3) reacting compound 2 with 2-picolinic acid to obtain a copper ion ratio fluorescent probe 1-methyl-4-(4-(2-pyridinecarbonyloxy)phenylvinyl)quinoline iodide, i.e., compound 1; and the application of the fluorescent probe is to identify copper ions with the fluorescent probe in a pure aqueous solution, and to use the ratio of fluorescence intensities at two different emission wavelengths (F 560nm / F 495nm ) changes to detect the presence or absence of copper ions. The probe of the present invention is simple to prepare and separate and purify, and the fluorescent probe molecule has the advantages of good selectivity, high sensitivity and fast response speed in a system where copper ions and other cations coexist.

Description

Technical Field

[0001] The invention belongs to the technical field of fluorescent probes for metal ion detection, and particularly relates to a copper ion ratio fluorescent probe and a preparation and application thereof. Background Art

[0002] In recent years, the development of monitoring technology for heavy metal and transition metal ions has attracted more and more attention. 2+ ) is the third most abundant cation in the human body and plays a vital role in physiological processes. In order to maintain a regular intake of Cu 2+ mediate the process and maintain an appropriate amount of Cu 2+ Cu in blood is very important. 2+ The average concentration of Cu was between 15.7 and 23.6 μM. 2+ Concentration levels, either deficiency or excess, can lead to serious diseases. Due to the wide application of Cu-mediated materials in industry and agriculture, Cu 2+ The continued discharge of Cu in drinking water will cause serious environmental pollution. For these reasons, the World Health Organization and the U.S. Environmental Protection Agency have determined that the 2+ The maximum permissible levels of Cu and Mg are 30 μM and 20 μM, respectively. 2+ physiological effects and environmental issues, and develop effective detection methods for Cu in biological and environmental systems 2+ method is very important.

[0003] To date, many quantitative detection methods for Cu have been developed. 2+ There are many analytical techniques, such as inductively coupled plasma mass spectrometry, atomic absorption spectroscopy, atomic emission spectroscopy and electrochemistry. However, these methods usually require expensive instruments, cumbersome sample preparation procedures, skilled operators, and long time consumption. Fluorescent probes have the advantages of strong specificity, high sensitivity, simple instruments, convenient operation, real-time monitoring, and fast response, which can be used to detect Cu 2+ Therefore, a large number of selective detection methods for Cu 2+ Usually, the coordination-based fluorescent probes cause the fluorescence signal to be turned off, which may lead to false positive results. In contrast, the chemical reaction strategy has become a new method for constructing fluorescent enhanced Cu 2+ An effective method for fluorescent probes. In fact, the design of Cu 2+ Ratiometric fluorescence probes are an attractive strategy. Fluorescent probes based on fluorescence intensity enhancement or attenuation are easily affected by many factors such as probe concentration, instrument efficiency, excitation intensity, and environmental changes. In contrast, ratiometric fluorescence probes can eliminate most or all of the above interferences through the self-calibration effect of two different fluorescence emission wavelengths. However, only a few Cu2+ Ratiometric fluorescent probes have been reported, and most of them are used to detect Cu in pure organic solvents or aqueous solutions containing organic solvents. 2+ Therefore, it is urgent to develop and research methods for the rapid and efficient detection of Cu in pure aqueous solution at room temperature. 2+ A new ratiometric fluorescent probe.

[0004] The semicyanine 4-(4-hydroxyphenylvinyl)-1-methylquinoline iodide based on quinoline salt not only has a typical "push-pull" structure and excellent optical properties, but also has good water solubility. Therefore, the copper ion ratio fluorescent probe of the present invention is a ratio fluorescent probe with 4-(4-hydroxyphenylvinyl)-1-methylquinoline iodide as a fluorophore and picolinate as a recognition unit. No literature or patent application similar to the present application was found after searching. Summary of the invention

[0005] The purpose of the present invention is to synthesize a copper ion ratio fluorescent probe for detecting copper ions in pure aqueous solution through molecular design in view of the deficiencies of the prior art and having good selectivity, high sensitivity and fast response speed.

[0006] The invention also provides a method for preparing the copper ion ratio fluorescent probe.

[0007] The present invention also provides application of the copper ion ratio fluorescent probe.

[0008] The present invention solves the technical problem by adopting the following technical solutions:

[0009] A copper ion ratio fluorescent probe, its molecular formula is C 24 H 19 IN2O2, the structural formula is as follows:

[0010]

[0011] A method for preparing a copper ion ratio fluorescent probe comprises the following steps:

[0012] (1) 4-Methylquinoline reacts with iodomethane to obtain 1,4-dimethylquinoline iodide, i.e., compound 3, whose structural formula is as follows:

[0013]

[0014] (2) reacting the compound 3 obtained in step (1) with 4-hydroxybenzaldehyde to obtain 4-(4-hydroxyphenylvinyl)-1-methylquinoline iodide, i.e., compound 2, whose structural formula is as follows:

[0015]

[0016] (3) reacting the compound 2 obtained in step (2) with 2-picolinic acid to obtain the copper ion ratio fluorescent probe 1-methyl-4-(4-(2-pyridinecarbonyloxy)phenylvinyl)quinoline iodide, i.e., compound 1, whose structural formula is as follows:

[0017]

[0018] Moreover, the specific method for obtaining compound 3 in step (1) is: dissolving 4-methylquinoline and iodomethane in toluene, heating under reflux for reaction for 3 hours under argon protection, cooling to room temperature after the reaction is complete, adding ethyl acetate to precipitate solid, filtering and washing with ethyl acetate, and collecting the solid to obtain compound 3.

[0019] Moreover, the ratio of 4-methylquinoline to methyl iodide is 1:1.5.

[0020] Moreover, the specific method for obtaining compound 2 in step (2) is: dissolving compound 3, 4-hydroxybenzaldehyde and piperidine in anhydrous ethanol, heating under reflux for reaction for 5 hours under argon protection, cooling to room temperature after the reaction is complete, adding ethyl acetate to precipitate solid, filtering and washing with anhydrous ethyl acetate, and collecting the solid to obtain compound 2.

[0021] Moreover, the ratio of the compound 3 to 4-hydroxybenzaldehyde and piperidine is 1:1.2:0.2.

[0022] Moreover, the specific method for obtaining compound 1 in step (3) is: dissolving compound 2, 2-pyridinecarboxylic acid, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride and 4-dimethylaminopyridine in dichloromethane, reacting at room temperature for 14 hours under argon protection, after the reaction is complete, solid precipitates, is filtered and washed with dichloromethane, and the collected solid is the copper ion ratio fluorescent probe, i.e., compound 1.

[0023] Moreover, the ratio of the compound 2 to 2-picolinic acid, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride and 4-dimethylaminopyridine is 1:1.3:2:0.4.

[0024] An application of a copper ion ratio fluorescent probe, the application is to use the fluorescent probe to identify copper ions in a pure aqueous solution, using the ratio of fluorescence intensity at two different emission wavelengths (F 560nm / F 495nm 0.41~9.55) changes to detect the presence or absence of copper ions.

[0025] Moreover, the maximum fluorescence emission wavelength of the probe solution is at 495 nm. When copper ions are added, the maximum fluorescence emission wavelength of the probe solution is red-shifted to 560 nm. The detection limit of copper ions is 0.62 μM.

[0026] Advantages and effects of the present invention

[0027] 1. The synthesis of the probe of the present invention only requires three steps, and the post-treatment only requires filtration, and the process is simple.

[0028] 2. The fluorescent probe molecule of the present invention has the advantages of good selectivity, high sensitivity and fast response speed in the coexistence system of copper ions and other cations. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 For compound 3 in implementation case 1 1 H NMR spectrum;

[0030] Figure 2 For compound 3 in implementation case 1 13 C NMR spectrum;

[0031] Figure 3 is the ESI-MS spectrum of compound 3 in implementation case 1;

[0032] Figure 4 For compound 2 in implementation case 1 1 H NMR spectrum;

[0033] Figure 5 For compound 2 in implementation case 1 13 C NMR spectrum;

[0034] Figure 6 is the ESI-MS spectrum of compound 2 in implementation case 1;

[0035] Figure 7 For compound 1 in implementation case 1 1 H NMR spectrum;

[0036] Figure 8 For compound 1 in implementation case 1 13 C NMR spectrum;

[0037] Fig. 9 is the ESI-MS spectrum of compound 1 in implementation case 1;

[0038] Fig.10 (a) is the fluorescence intensity ratio of compound 1 and compound 2 (F 560nm / F 495nm ), (b) the effect of pH on compound 1 and Cu 2+ The fluorescence intensity ratio before and after the reaction (F 560nm / F 495nm )’s impact diagram;

[0039] Fig.11(a) shows the reaction of compound 1 with Cu under the optimal test conditions. 2+ Schematic diagram of the absorption spectrum change of the reaction, (b) is compound 1 and Cu 2+ The absorbance ratio (A 415nm / A385 nm ) Schematic diagram of changes over time;

[0040] Fig.12 (a) shows the reaction of compound 1 with Cu under the optimal test conditions. 2+ Schematic diagram of the fluorescence spectrum changes of the reaction, (b) is compound 1 and Cu 2+ The fluorescence intensity ratio of the reaction (F 560nm / F 495nm ) Schematic diagram of changes over time;

[0041] Fig.13 (a) shows the reaction of compound 1 with different concentrations of Cu 2+ The fluorescence intensity ratio of the reaction (F 560nm / F 495nm ) is a schematic diagram of the change of the fluorescence intensity ratio (F 560nm / F 495nm ) 2+ Schematic diagram of concentration changes;

[0042] Fig.14 is the fluorescence intensity ratio of compound 1 before and after the reaction with different metal ions (F 560nm / F 495nm ) (black columns represent probes treated with the labeled metal ions only, gray columns represent probes treated with the labeled metal ions and then treated with Cu 2+ ). DETAILED DESCRIPTION

[0043] The embodiments of the present invention are further described in detail below: It should be emphasized that the embodiments described in the present invention are illustrative rather than restrictive, and therefore the present invention is not limited to the embodiments described in the specific implementation manners, and any other implementation manners derived by those skilled in the art based on the technical solutions of the present invention also fall within the scope of protection of the present invention.

[0044] Example

[0045] (I) Preparation of target compound copper ion fluorescent probe

[0046] (1) Synthesis of Compound 3

[0047]

[0048] 4-Methylquinoline (1.43 g, 10 mmol) and iodomethane (2.13 g, 15 mmol) were dissolved in toluene (10 ml), and heated under reflux for 3 hours under argon protection. After the reaction was complete, the mixture was cooled to room temperature, ethyl acetate was added to precipitate the solid, and the solid was filtered and washed with ethyl acetate. The solid was collected with a yield of 95%.

[0049] Compound 3 1 H NMR spectrum Figure 1 As shown, 1 HNMR (400MHz, d6-DMSO, ppm) δ9.42 (d, J = 6.0 Hz, 1H), 8.49 (d, J = 8.8 Hz, 2H), 8.26-8.22 (m, 1H), 8.07-8.01 (m, 2H), 4.59 (s, 3H), 2.98 (s, 3H).

[0050] Compound 3 13 C NMR spectrum Figure 2 As shown, 13 C NMR (100MHz, d6-DMSO, ppm) δ157.97,148.75,137.45,134.81,129.52,128.28,126.66,122.33,119.41,45.15,19.67.

[0051] The ESI-MS spectrum of compound 3 is as follows Figure 3 As shown, MS-ESI m / z for C 11 H 12 N + ([MI] + ):calcd:158.1,found:158.1.

[0052] (2) Synthesis of Compound 2

[0053]

[0054] Compound 3 (1.43 g, 5 mmol), 4-hydroxybenzaldehyde (0.73 g, 6 mmol) and piperidine (0.1 mL, 1 mmol) were dissolved in anhydrous ethanol (15 mL) and heated under reflux under argon protection for 5 hours. After the reaction was complete, it was cooled to room temperature, ethyl acetate was added to precipitate the solid, filtered and washed with anhydrous ethyl acetate, and the solid was collected. The yield was 90%.

[0055] Compound 2 1 H NMR spectrum Figure 4 As shown, 1HNMR(400MHz,d6-DMSO,ppm)δ9.25(d,J=6.4Hz,1H),9.01(d,J=8.4Hz,1H),8.43-8.38(m,2H),8.23(t,J=7.6 Hz, 1H), 8.16-8.05 (m, 2H), 8.00 (t, J = 8.0Hz, 1H), 7.86 (d, J = 8.4Hz, 2H), 6.89 (d, J = 8.8Hz, 2H), 4.50 (s, 3H).

[0056] Compound 2 13 C NMR spectrum Figure 5 As shown, 13 C NMR(100MHz,d6-DMSO,ppm)δ160.49,152.96,147.49,143.51,138.67,134.77,1 31.14,128.90,126.68,126.35,126.00,119.16,115.98,115.90,115.18,44.41.

[0057] The ESI-MS spectrum of compound 2 is as follows Figure 6 As shown, MS-ESI m / z for C 18 H 16 NO + ([MI] + ):calcd:262.1,found:262.1.

[0058] (3) Synthesis of Compound 1

[0059]

[0060] Compound 2 (583.9 mg, 1.5 mmol), 2-picolinic acid (244.2 mg, 2 mmol), 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (575.1 mg, 3 mmol) and 4-dimethylaminopyridine (73.3 mg, 0.6 mmol) were dissolved in dichloromethane (15 mL) and reacted at room temperature for 14 hours under argon protection. After the reaction was complete, solid precipitated, which was filtered and washed with dichloromethane. The solid was collected with a yield of 81%.

[0061] Compound 1 1 H NMR spectrum Figure 7 As shown, 1HNMR(400MHz,d6-DMSO,ppm)δ9.45(d,J=6.4Hz,1H),9.07(d,J=8.4Hz,1H),8.84-8.83(m,1H),8.54(d,J=6.4Hz,1H),8.47(d,J= 8.8Hz,1H),8.35(d,J=16.0Hz,1H),8.29-8.20(m,3H),8.14-8.04(m,4H),7.78-7.75(m,1H),7.48(d,J=8.8Hz,2H),4.58(s,3H).

[0062] Compound 1 13 C NMR spectrum Figure 8 As shown, 13 C NMR(100MHz,d6-DMSO,ppm)δ163.26,152.42,152.25,150.06,148.25,146.57,141.72,138.71,137.80,1 35.01,133.50,130.18,129.31,128.10,126.53,126.38,125.81,122.49,120.19,119.38,116.45,44.76.

[0063] The ESI-MS spectrum of compound 1 is as follows Fig. 9 As shown, MS-ESI z / m for C 24 H 19 N2O2 + ([MI] + ):calcd:367.1,found:367.1.

[0064] (II) Effects of pH changes on compound 1 and its recognition of copper ions and the fluorescence intensity of compound 2

[0065] Compound 1 and Compound 2 synthesized in Example (I) were dissolved in dimethyl sulfoxide to prepare 2 mmol / L stock solutions. When the pH value was different, the fluorescence properties of Compound 1 and its recognition of copper ions and Compound 2 were measured at room temperature with 405 nm as the excitation light. The results were as follows: Fig.10 shown. Fig.10 (a) (a) is the fluorescence intensity ratio of compounds 1 and 2 to pH value (F 560nm / F 495nm ), (b) the effect of pH on the 2+ The fluorescence intensity ratio before and after the reaction (F 560nm / F 495nmThe experimental results show that when pH = 4.0-12.0, the fluorescence intensity ratio (F 560nm / F 495nm ) remained basically unchanged, and the fluorescence intensity ratio of compound 2 (F 560nm / F 495nm ) was almost unaffected at pH = 4.0-9.0, but decreased rapidly from pH 9.0 to 12.0; Compound 1 had no effect on Cu 2+ The fluorescence intensity ratio (F 560nm / F 495nm ) The pH value increased rapidly from 5.0 to 7.4; increased slightly from 7.4 to 9.0; and decreased rapidly from 9.0 to 12.0. The optimal pH value tested was 7.4.

[0066] (III) Absorption and fluorescence spectra of compound 1

[0067] Under the optimal test conditions, i.e., 10 mM HEPES, pH 7.4, 25°C, the absorption and fluorescence spectra of compound 1 were studied. The results are as follows: Fig.11 and Fig.12 shown. Fig.11 (a) shows the reaction of compound 1 with Cu under the optimal test conditions. 2+ Absorption spectrum changes of the reaction, (b) is compound 1 and Cu 2+ The absorbance ratio (A 415nm / A385 nm ) changes over time; Fig.12 (a) shows the reaction of compound 1 with Cu under the optimal test conditions. 2+ The fluorescence spectrum changes of the reaction, (b) is compound 1 and Cu 2+ The fluorescence intensity ratio of the reaction (F 560nm / F 495nm ) changes with time. The experimental results show that compound 1 can achieve Cu 2+ Rapid detection.

[0068] (IV) Detection of Cu by Compound 1 2+ Sensitivity study

[0069] Under the optimal test conditions, compound 1 was tested for Cu 2+ The sensitivity of Fig.13 shown. Fig.13 (a) shows the reaction of compound 1 with different concentrations of Cu 2+ The fluorescence intensity ratio of the reaction (F 560nm / F 495nm ) changes with time, and (b) is the fluorescence intensity ratio of compound 1 (F 560nm / F 495nm ) 2+The experimental results show that Cu 2+ The higher the concentration, the higher the fluorescence intensity ratio (F 503nm / F 448nm ) changes more and faster, when Cu 2+ When the concentration is 36 μM, the maximum Fig.13 (a)). Fig.13 (b) It can be inferred that compound 1 has an affinity for Cu 2+ The detection limit is 0.62 μM, which is much lower than the maximum Cu content in safe drinking water specified by the World Health Organization and the U.S. Environmental Protection Agency. 2+ concentration.

[0070] (V) Compound 1 for Cu 2+ Selective research

[0071] To test the effect of compound 1 on Cu 2+ The selectivity of the fluorescence intensity ratio (F 560nm / F 495nm ) were experimentally studied (e.g. Fig.14 The results showed that compound 1 has a 2+ The detection is not interfered by other potentially competitive metal ions. 2+ Highly selective.

Claims

1. A copper ion ratio fluorescent probe, characterized in that: Its molecular formula is C 24 H 19 IN2O2, the structural formula is as follows:

2. A method for preparing the copper ion ratio fluorescent probe according to claim 1, characterized in that The steps include: (1) 4-Methylquinoline reacts with iodomethane to obtain 1,4-dimethylquinoline iodide, i.e., compound 3, whose structural formula is as follows: (2) reacting the compound 3 obtained in step (1) with 4-hydroxybenzaldehyde to obtain 4-(4-hydroxyphenylvinyl)-1-methylquinoline iodide, i.e., compound 2, whose structural formula is as follows: (3) reacting the compound 2 obtained in step (2) with 2-picolinic acid to obtain the copper ion ratio fluorescent probe 1-methyl-4-(4-(2-pyridinecarbonyloxy)phenylvinyl)quinoline iodide, i.e., compound 1, whose structural formula is as follows:

3. The method for preparing the copper ion ratio fluorescent probe according to claim 2, characterized in that: The specific method for obtaining compound 3 in step (1) is as follows: 4-methylquinoline and iodomethane are dissolved in toluene, and the mixture is heated under reflux for 3 hours under argon protection. After the reaction is complete, the mixture is cooled to room temperature, ethyl acetate is added to precipitate a solid, and the solid is filtered and washed with ethyl acetate. The solid collected is compound 3.

4. The method for preparing the copper ion ratio fluorescent probe according to claim 3, characterized in that: The ratio of 4-methylquinoline to methyl iodide is 1:1.

5.

5. The method for preparing the copper ion ratio fluorescent probe according to claim 2, characterized in that: The specific method for obtaining compound 2 in step (2) is as follows: dissolving compound 3, 4-hydroxybenzaldehyde and piperidine in anhydrous ethanol, heating under reflux for reaction for 5 hours under argon protection, cooling to room temperature after the reaction is complete, adding ethyl acetate to precipitate solid, filtering and washing with anhydrous ethyl acetate, and collecting the solid to obtain compound 2.

6. The method for preparing the copper ion ratio fluorescent probe according to claim 5, characterized in that: The ratio of the compound 3 to 4-hydroxybenzaldehyde and piperidine is 1:1.2:0.

2.

7. The method for preparing the copper ion ratio fluorescent probe according to claim 2, characterized in that: The specific method for obtaining compound 1 in step (3) is as follows: dissolving compound 2, 2-pyridinecarboxylic acid, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride and 4-dimethylaminopyridine in dichloromethane, reacting at room temperature for 14 hours under argon protection. After the reaction is complete, solid precipitates, which is filtered and washed with dichloromethane. The collected solid is the copper ion ratio fluorescent probe, i.e., compound 1.

8. The method for preparing the copper ion ratio fluorescent probe according to claim 7, characterized in that: The ratio of the compound 2 to 2-pyridinecarboxylic acid, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride and 4-dimethylaminopyridine is 1:1.3:2:0.

4.

9. An application of the copper ion ratio fluorescent probe according to claim 1, characterized in that: This application is to use fluorescent probes to identify copper ions in pure aqueous solution, using the ratio of fluorescence intensities at two different emission wavelengths. 560nm / F 495nm Changes to detect the presence or absence of copper ions.

10. The use of the copper ion ratio fluorescent probe according to claim 9, characterized in that: The maximum fluorescence emission wavelength of the probe solution is at 495 nm. When copper ions are added, the maximum fluorescence emission wavelength of the probe solution is red-shifted to 560 nm. The detection limit of copper ions is 0.62 μM.

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