A benzimidazole Cu 2+ Fluorescent probes, their preparation methods and applications
By synthesizing benzimidazole-based Cu2+ fluorescent probes, the problems of high cost and complexity of existing detection methods have been solved, achieving high sensitivity and specificity for Cu2+ detection and enabling real-time monitoring.
Patent Information
- Application Number
- CN202211463629.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2022-11-22
- Publication Date
- 2025-10-31
- Estimated Expiration
- 2042-11-22
AI Technical Summary
Existing Cu2+ detection methods are costly, complex, and lack timeliness and sensitivity, making it difficult to achieve large-scale operations and real-time monitoring.
A benzimidazole-based Cu2+ fluorescent probe was designed and synthesized by nucleophilic addition reaction of o-phenylenediamine and terephthalaldehyde followed by a dehydration step, and then reacted with 4-phenyl-3-thioaminourea in glacial acetic acid and methanol solvents to prepare a Cu2+ fluorescent probe with high sensitivity and specific recognition.
It achieves highly sensitive detection of Cu2+, with timeliness and specificity, enabling real-time monitoring under low-cost conditions, and is not affected by interference from other metal ions.
Smart Images
Figure CN116102503B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of fluorescent probe technology, and more specifically to a benzimidazole Cu 2+ Fluorescent probes, their preparation methods, and applications. Background Technology
[0002] With continuous industrial development, environmental pollution has become severe, and more and more heavy metals are gradually infiltrating our lives. The human body contains various essential metallic elements to maintain normal bodily functions. Both excessive and insufficient levels of these elements can cause varying degrees of harm to human health. Copper, in particular, is an indispensable trace element in living organisms, participating in various physiological activities as a nutrient. A deficiency of Cu in the body... 2+ This can lead to nutritional imbalances in organisms, resulting in metabolic disorders and subsequently disrupting the body's internal cycles. Additionally, Cu... 2+ Cu participates in various physiological activities in the human body, such as balancing enzyme activity and transmitting and receiving neurotransmitters. Excessive intake can lead to serious illnesses such as poisoning. Cu in the environment... 2+ The accumulation of Cu can inhibit the growth of plants, animals, and microorganisms, and disrupt the activity of soil enzymes, significantly impacting ecosystem stability. Therefore, Cu... 2+ It plays a crucial role in life systems and the ecological environment.
[0003] Common Cu 2+ Detection methods include atomic absorption spectrometry, spectrophotometry, and cyclic voltammetry. However, these common methods are costly, complex, and difficult to implement in large-scale operations and real-time monitoring, thus lacking timeliness to some extent. Fluorescence analysis is a superior modern analytical tool. In biological cells, the detection of metal ion content is based on changes in the position and intensity of fluorescence signals. Its advantages include lower cost, simple operation, specific selection of particular ions, high sensitivity, and the ability to meet the real-time monitoring requirements of the analyte, thus possessing timeliness. Currently, many methods for detecting Cu... 2+ Fluorescent probe molecules have been widely used in various fields, but due to their shortcomings in selectivity and sensitivity, and in practical applications for detecting Cu... 2+ The detection process involves complex and demanding conditions; therefore, a novel sensitive and convenient Cu detection method was designed and synthesized. 2+ Fluorescent probes are of great significance in the fields of life sciences and ecological environment. Summary of the Invention
[0004] To address the above problems, this invention provides a benzimidazole-based Cu 2+ Fluorescent probes, their preparation methods, and applications.
[0005] The first objective of this invention is to provide a benzimidazole Cu 2+ The fluorescent probe has the following structural formula:
[0006]
[0007] A second objective of this invention is to provide the above-mentioned benzimidazole Cu 2+ The fluorescent probe is prepared according to the following steps:
[0008] Step 1: Using anhydrous ethanol as a solvent, o-phenylenediamine and terephthalaldehyde undergo a nucleophilic addition reaction to further dehydrate. After the reaction is complete, a reaction solution is obtained. The reaction solution is then post-treated to obtain the intermediate 4-(1H-benzimidazol-2-yl)benzaldehyde.
[0009] The synthesis route is as follows:
[0010]
[0011] Step 2: Using methanol as the reaction solvent, 4-(1H-benzimidazol-2-yl)benzaldehyde and 4-phenyl-3-thioaminourea undergo a nucleophilic addition reaction under the catalysis of glacial acetic acid to prepare benzimidazolium-based Cu. 2+ Fluorescent probe;
[0012] The synthesis route is as follows:
[0013]
[0014] Preferably, in step 1, the synthesis steps of intermediate 4-(1H-benzimidazol-2-yl)benzaldehyde are as follows:
[0015] Anhydrous ethanol was added to o-phenylenediamine and terephthalaldehyde, and the solution changed from colorless to orange-red. The mixture was heated under reflux at 75-85℃ for 1-4 hours until the reaction was complete, and the reaction solution was obtained. After cooling, the pH was adjusted to 5.0-5.5 with NaHCO3, and the solution was rotated to evaporate to obtain the crude product. After separation and purification, the crude product was rotated to evaporate and dried to obtain the intermediate 4-(1H-benzimidazol-2-yl)benzaldehyde.
[0016] The ratio of o-phenylenediamine, terephthalaldehyde, and ethanol is 4 mmol: 12 mmol: 50-60 mL.
[0017] Preferably, in step 1, the crude product is separated and purified twice by silica gel column chromatography, with the eluent being dichloromethane and ethyl acetate in a volume ratio of 8-10:1; and the developing solvent being dichloromethane and ethyl acetate in a volume ratio of 3-6:1.
[0018] Preferably, in step 2, benzimidazole Cu 2+ The synthesis steps of the fluorescent probe are as follows:
[0019] Glacial acetic acid and methanol were added to 4-(1H-benzimidazol-2-yl)benzaldehyde and 4-phenyl-3-thioaminourea, and the mixture was heated under reflux at 70-75°C for 12-16 h. After the reaction was completed, post-treatment was performed to obtain benzimidazol-based Cu. 2+ Fluorescent probe;
[0020] The ratio of 4-(1H-benzimidazol-2-yl)benzaldehyde, 4-phenyl-3-thioaminourea, glacial acetic acid and methanol is 1 mmol: 1 mmol: 0.15-0.2 mL: 30-35 mL.
[0021] Preferably, the post-processing steps in step 2 are as follows: After the reaction is complete, the solid is cooled and filtered, dissolved in methanol, allowed to crystallize twice, filtered, rotary evaporated, and dried to obtain benzimidazole Cu. 2+ Fluorescent probe.
[0022] A third objective of this invention is to provide the above-mentioned benzimidazole Cu 2+ Fluorescent probes for detecting Cu 2+ Applications in [the context of the text].
[0023] Preferably, acetonitrile is used as the detection solution to test for Cu content. 2+ The solution was added to a benzimidazole Cu 2+ An acetonitrile solution of the fluorescent probe was prepared, and fluorescence detection was performed at 333-600 nm.
[0024] Preferably, the detection wavelength is 426 nm.
[0025] Preferably, the Cu 2+ The concentration is ≥2.04×10 -7 mol / L.
[0026] Compared with the prior art, the present invention has the following beneficial effects:
[0027] This invention synthesizes a benzimidazole-based Cu using benzimidazole as the backbone. 2+ Fluorescent probe P1, compared to other competing ions in solution, exhibits higher resistance to Cu. 2+ It exhibits significant specificity. When excitation light is emitted at an excitation wavelength of 333 nm, the fluorescence intensity of probe P1 decreases significantly at 426 nm, indicating that probe P1 is effective against Cu. 2+ It has high sensitivity, and the addition of Cu 2+ The molecule reacts with probe P1 to form a stable complex, resulting in a significant decrease in fluorescence intensity, which is unaffected by other metal ions. Sensitivity studies of probe P1 revealed that the fluorescence intensity of probe P1 decreases with increasing Cu content. 2+As the concentration increases, the quenching phenomenon becomes more pronounced. Additionally, probe P1 has an effect on Cu... 2+ The detection showed good linear correlation and a low detection limit. Experiments using probe P1 revealed that Cu... 2+ Probe P1 can achieve specific recognition, and the acetonitrile solution has no effect on the process. Probe P1 and Cu 2+ The binding reaches a stable state within 12 minutes, demonstrating time-sensitivity. Probe P1 detects Cu... 2+ It has potential application value. Attached Figure Description
[0028] Figure 1 The infrared spectrum of 4-(1H-benzimidazol-2-yl)benzaldehyde prepared in Example 1;
[0029] Figure 2 The mass spectrum of 4-(1H-benzimidazol-2-yl)benzaldehyde prepared in Example 1;
[0030] Figure 3 The infrared absorption spectrum of 2-(4-(1H-benzimidazol-2-yl)benzyl)-N-phenylhydrazine-1-carbon thioamide prepared in Example 1;
[0031] Figure 4 The mass spectrum of 2-(4-(1H-benzimidazol-2-yl)benzylidene)-N-phenylhydrazine-1-carbonthioamide prepared in Example 1;
[0032] Figure 5 This is a graph showing the determination of ions using ultraviolet-visible absorption spectroscopy.
[0033] Figure 6 This is a fluorescence spectroscopy ion determination diagram;
[0034] Figure 7 To improve the anti-interference capability of probe P1;
[0035] Figure 8 The effect of different copper ion concentrations on probe P1;
[0036] Figure 9 The fluorescence intensity of probe P1 at 426 nm and Cu 2+ Linear fitting plot between;
[0037] Figure 10 For probe P1 to Cu 2+ Time response. Detailed Implementation
[0038] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0039] Unless otherwise specified, the raw materials used in the following examples are all conventional raw materials. Test methods in the following examples that do not specify specific conditions are generally performed under conventional conditions or as recommended by the respective manufacturers.
[0040] The benzimidazole Cu provided by this invention 2+ The fluorescent probe has the following structural formula:
[0041]
[0042] The benzimidazole Cu provided by this invention 2+ The preparation method of the fluorescent probe is as follows:
[0043] Step 1: o-phenylenediamine and terephthalaldehyde undergo a nucleophilic addition reaction and further condensation and dehydration to generate the product under the condition of anhydrous ethanol as solvent. After the reaction is completed, the reaction solution is obtained. After cooling, the reaction solution is acidified and purified to obtain the intermediate 4-(1H-benzimidazol-2-yl)benzaldehyde.
[0044] The synthesis route is as follows:
[0045]
[0046] Step 2: In the presence of methanol as the reaction solvent and glacial acetic acid as the catalyst, 4-(1H-benzimidazol-2-yl)benzaldehyde and 4-phenyl-3-thioaminourea undergo a nucleophilic addition reaction to prepare benzimidazol-based Cu. 2+ Fluorescent probe;
[0047] The synthesis route is as follows:
[0048]
[0049] Specific examples for preparing the compounds of the present invention are as follows:
[0050] Example 1
[0051] A benzimidazole Cu 2+ The fluorescent probe is prepared according to the following steps:
[0052] Step 1: Weigh 4 mmol (0.5395 g) of o-phenylenediamine and 12 mmol (1.6755 g) of terephthalaldehyde, place them in a 100 mL three-necked flask, add 50 mL of anhydrous ethanol. The solution rapidly changes from colorless to a bright orange-red. Heat at 78 °C and reflux for 2 h. After the reaction is complete, allow the reaction solution to cool, adjust the pH to 5.0 with NaHCO3, and monitor the reaction by TLC throughout. Rotary evaporation yields the crude product. The crude product is then purified twice by silica gel column chromatography, using dichloromethane:ethyl acetate = 10:1 (v / v) as the eluent and dichloromethane:ethyl acetate = 5:1 (v / v) as the developing solvent. Rotary evaporation and drying yield a pale yellow solid, the intermediate 4-(1H-benzimidazol-2-yl)benzaldehyde, denoted as X1. The weight of X1 was 0.482 g, the yield was 54.29%, and its melting point was measured to be 279.3–289.4 °C.
[0053] Step 2: Weigh 1 mmol (0.2208 g) of 4-(1H-benzimidazol-2-yl)benzaldehyde and 1 mmol (0.167 g) of 4-phenyl-3-thioaminourea, place them in a 100 mL three-necked flask, add 0.15 mL of glacial acetic acid and 30 mL of methanol, heat at 70 °C, and reflux for 12 h. After the reaction is complete, allow the reaction solution to cool, filter, dissolve the obtained solid in an appropriate amount of methanol, allow to stand for crystallization twice, filter, evaporate by rotary evaporation, and dry to obtain a light yellow solid (4-(1H-benzimidazol-2-yl)benzylene)-N-phenylhydrazine-1-carbon thioamide, i.e., benzimidazole Cu 2+ The fluorescent probe, denoted as P1, was weighed to be 0.177 g, with a yield of 47.63%, and its melting point was measured to be 226.1–241.3 °C.
[0054] Example 2
[0055] A benzimidazole Cu 2+ The fluorescent probe is prepared according to the following steps:
[0056] Step 1: Weigh 4 mmol (0.5395 g) of o-phenylenediamine and 12 mmol (1.6755 g) of terephthalaldehyde, place them in a 100 mL three-necked flask, add 60 mL of anhydrous ethanol. The solution rapidly changes from colorless to a bright orange-red. Heat at 75 °C and reflux for 4 h. After the reaction is complete, allow the reaction solution to cool, adjust the pH to 5.1 with NaHCO3, and monitor the reaction by TLC throughout. Rotary evaporation yields the crude product. The crude product is then purified twice by silica gel column chromatography, using dichloromethane:ethyl acetate = 10:1 (v / v) as the eluent and dichloromethane:ethyl acetate = 5:1 (v / v) as the developing solvent. Rotary evaporation and drying yield a pale yellow solid, the intermediate 4-(1H-benzimidazol-2-yl)benzaldehyde.
[0057] Step 2: Weigh 1 mmol (0.2208 g) of 4-(1H-benzimidazol-2-yl)benzaldehyde and 1 mmol (0.167 g) of 4-phenyl-3-thioaminourea, place them in a 100 mL three-necked flask, add 0.20 mL of glacial acetic acid and 35 mL of methanol, and heat at 75 °C for reflux evaporation for 13 h. After the reaction is complete, allow the reaction solution to cool, filter, dissolve the obtained solid in an appropriate amount of methanol, allow to stand for crystallization twice, filter, evaporate by rotary evaporation, and dry to obtain a light yellow solid (4-(1H-benzimidazol-2-yl)benzyl)-N-phenylhydrazine-1-carbon thioamide, i.e., benzimidazole Cu 2+ Fluorescent probe.
[0058] Example 3
[0059] A benzimidazole Cu 2+ The fluorescent probe is prepared according to the following steps:
[0060] Step 1: Weigh 4 mmol (0.5395 g) of o-phenylenediamine and 12 mmol (1.6755 g) of terephthalaldehyde, place them in a 100 mL three-necked flask, add 55 mL of anhydrous ethanol. The solution rapidly changes from colorless to a bright orange-red. Heat at 85 °C and reflux for 1 h. After the reaction is complete, allow the reaction solution to cool, adjust the pH to 5.5 with NaHCO3, and monitor the reaction by TLC throughout. Rotary evaporation yields the crude product. The crude product is then purified twice by silica gel column chromatography, using dichloromethane:ethyl acetate = 8:1 (v / v) as the eluent and dichloromethane:ethyl acetate = 6:1 (v / v) as the developing solvent. Rotary evaporation and drying yield a pale yellow solid, the intermediate 4-(1H-benzimidazol-2-yl)benzaldehyde.
[0061] Step 2: Weigh 1 mmol (0.2208 g) of 4-(1H-benzimidazol-2-yl)benzaldehyde and 1 mmol (0.167 g) of 4-phenyl-3-thioaminourea, place them in a 100 mL three-necked flask, add 0.18 mL of glacial acetic acid and 32 mL of methanol, and heat at 73 °C for reflux evaporation for 16 h. After the reaction is complete, allow the reaction solution to cool, filter, dissolve the obtained solid in an appropriate amount of methanol, allow to stand for crystallization twice, filter, evaporate by rotary evaporation, and dry to obtain a light yellow solid (4-(1H-benzimidazol-2-yl)benzylene)-N-phenylhydrazine-1-carbon thioamide, i.e., benzimidazole Cu 2+ Fluorescent probe.
[0062] Example 4
[0063] A benzimidazole Cu 2+ The fluorescent probe is prepared according to the following steps:
[0064] Step 1: Weigh 4 mmol (0.5395 g) of o-phenylenediamine and 12 mmol (1.6755 g) of terephthalaldehyde, place them in a 100 mL three-necked flask, add 57 mL of anhydrous ethanol. The solution rapidly changes from colorless to a bright orange-red. Heat at 80 °C and reflux for 3 h. After the reaction is complete, allow the reaction solution to cool, adjust the pH to 5.3 with NaHCO3, and monitor the entire process by TLC. Rotary evaporation yields the crude product. The crude product is then purified twice by silica gel column chromatography, with dichloromethane:ethyl acetate = 9:1 (v / v) as the eluent and dichloromethane:ethyl acetate = 3:1 (v / v) as the developing solvent. Rotary evaporation and drying yield a pale yellow solid, namely the intermediate 4-(1H-benzimidazol-2-yl)benzaldehyde.
[0065] Step 2: Weigh 1 mmol (0.2208 g) of 4-(1H-benzimidazol-2-yl)benzaldehyde and 1 mmol (0.167 g) of 4-phenyl-3-thioaminourea, place them in a 100 mL three-necked flask, add 0.15 mL of glacial acetic acid and 35 mL of methanol, and heat at 70 °C for reflux evaporation for 12 h. After the reaction is complete, allow the reaction solution to cool, filter, dissolve the obtained solid in an appropriate amount of methanol, allow to stand for crystallization twice, filter, evaporate by rotary evaporation, and dry to obtain a light yellow solid (4-(1H-benzimidazol-2-yl)benzylene)-N-phenylhydrazine-1-carbon thioamide, i.e., benzimidazole Cu 2+ Fluorescent probe.
[0066] The benzimidazole Cu prepared in Examples 1-4 2+ The performance of fluorescent probes is basically the same. To verify the effectiveness of this invention, the following only describes the benzimidazole Cu prepared in Example 1.2+ The performance of the fluorescent probe was tested, and the specific process is as follows.
[0067] I. Structural Analysis
[0068] Figure 1 The infrared spectrum of 4-(1H-benzimidazol-2-yl)benzaldehyde (X1) is shown below. Figure 1 It can be determined that the range is 2000-1500cm. -1 The presence of absorption peaks indicates the presence of double bonds, including skeletal vibrations in aromatic hydrocarbons, -NH2, and C=N; 3100-3000 cm⁻¹ -1 The presence of three relatively weak absorption peaks indicates the stretching vibration of the CH bond on the benzene ring; 1520-1430 cm⁻¹ -1 The presence of an absorption peak at 825 cm⁻¹ indicates the presence of a benzene ring; -1 The presence of an absorption peak at 1690 cm⁻¹ indicates the presence of para-substitution of the benzene ring; -1 The presence of an absorption peak at 1690-1640 cm⁻¹ indicates the presence of an aldehyde carbonyl group on the benzene ring; -1 The presence of a moderate absorption peak at 1360-1310 cm⁻¹ indicates the presence of stretching vibrations of the C=N group; -1 An absorption peak appears at the point, indicating the presence of a CN bond; based on the above, it can be deduced that the structure of the measured substance is 4-(1H-benzimidazol-2-yl)benzaldehyde (X1).
[0069] Figure 2 The mass spectrum of 4-(1H-benzimidazol-2-yl)benzaldehyde is shown below. Figure 2 The display shows that ([C) 14 H 10 [N2O]+H) + If the value is 223.0875, then the molecular ion peak should be 222.0875, which is consistent with the mass fraction of 4-(1H-benzimidazol-2-yl)benzaldehyde, 222.08, indicating that the obtained substance is consistent with the theoretical product.
[0070] Figure 3 The infrared absorption spectrum of 2-(4-(1H-benzimidazol-2-yl)benzyl)-N-phenylhydrazine-1-carbonthioamide (P1) is shown below. Figure 3 It can be determined that it is between 2000-1500cm -1 The presence of absorption peaks indicates the presence of double bonds, including skeletal vibrations in aromatic hydrocarbons, -NH2, and C=N; 3100-3000 cm⁻¹ -1 The presence of three relatively weak absorption peaks indicates the stretching vibration of the CH bond on the benzene ring; 1520-1430 cm⁻¹ -1 The presence of an absorption peak at 825 cm⁻¹ indicates the presence of a benzene ring; -1The presence of an absorption peak at 1690-1640 cm⁻¹ indicates the presence of para-substitution of the benzene ring; -1 The presence of a moderate absorption peak at 1360-1310 cm⁻¹ indicates the presence of stretching vibrations of the C=N group; -1 An absorption peak appears at 1254 cm⁻¹, indicating the presence of CN bonds; -1 1203cm -1 The presence of an absorption peak at 1690-1640 cm⁻¹ indicates the presence of stretching vibrations of the C=S thiourea group; -1 The presence of a moderate absorption peak indicates the presence of stretching vibrations of the C=N group; therefore, it can be deduced that the structure of the measured substance is the target probe P1.
[0071] Figure 4 The mass spectrum of 2-(4-(1H-benzimidazol-2-yl)benzyl)-N-phenylhydrazine-1-carbonthioamide is obtained from... Figure 4 The display shows that ([C) 21 H 17 N5S]+H) + If the value is 373.1575, then the molecular ion peak is 372.1575, which is consistent with the mass fraction of 372.12 for 2-(4-(1H-benzimidazol-2-yl)benzylidene)-N-phenylhydrazine-1-carbon thioamide, indicating that the obtained substance is consistent with the theoretical product.
[0072] II. Research on Optical Performance
[0073] 1. Preparation of the detection solution
[0074] Weigh a certain mass of 2-(4-(1H-benzimidazol-2-yl)benzyl)-N-phenylhydrazine-1-carbosulfan, dissolve it in acetonitrile solution, and prepare a solution with a concentration of 10. -4 mol / L, 10 -5 A sample solution of mol / L was prepared. Different nitrates were weighed, dissolved in pure water, and prepared to a concentration of 10 mol / L. -1 A mol / L solution of metal cations.
[0075] 2. Selectivity study of probe P1
[0076] To investigate the selectivity of probe P1 for specific metal ions, this invention primarily employs ultraviolet-visible spectroscopy and fluorescence spectroscopy analysis methods, such as... Figures 5-6 As shown. The selectivity of the probe was determined by wavelength shift and changes in fluorescence intensity. A series of P1 concentrations of 10 were used in a test background of acetonitrile solution. -4 Add 5 μl of each mol / L sample to a concentration of 10 - 1 The solutions are in mol / L concentrations containing different metal ions, with the metal ions being Ag. + Al3+ Ba 2+ Cd 2+ Cu 2+ Ca 2+ Hg 2+ K + Mg 2+ Na + Mix well and allow to stabilize before performing spectral detection (333-600nm). Figure 5 As shown, Cu was added 2+ The sample solution relative to that containing only P1 (10 -4 The spectrum of the (mol / L) sample solution showed a significant blue shift. For example... Figure 6 As shown, in the control group sample containing only P1, a strong fluorescence emission was observed at 426 nm when the excitation wavelength was 333 nm. The addition of Cu... 2+ Then, using probe P1-Cu 2+ The fluorescence intensity of the solution in the system was significantly reduced in the fluorescence spectrum. This indicates that probe P1 is effective in selectively recognizing Cu. 2+ It has a very good effect.
[0077] 3. Study on the anti-interference ability of probe P1
[0078] To further investigate whether probe P1 affects Cu 2+ It possesses specific recognition capabilities, allowing for competition experiments when other metal ions are introduced into the system. For example... Figure 7 As shown, in this invention, other metal ions are first added, and after they stabilize, Cu is added to the system of probe P1 and other metal ions. 2+ The fluorescence intensity of each mixture was observed using fluorescence spectroscopy to study the effect of other metal ions on probe P1 using Cu. 2+ The degree of interference detected. Experimental results show that after adding a series of metal ions to the probe P1 solution, the fluorescence intensity in the system did not change significantly, while the addition of Cu... 2+ Subsequently, the fluorescence intensity decreased significantly, indicating that probe P1 can react with Cu. 2+ It can perform specific recognition and is not affected by other metal ions.
[0079] 4. Sensitivity study of probe P1
[0080] To investigate the effect of probe P1 on Cu 2+ The sensitivity of the detection varies depending on the concentration of Cu. 2+ Add to probe P1(10 - 4 In a sample solution with a concentration of (mol / L), the change in fluorescence intensity was observed using fluorescence spectroscopy. For example... Figure 8 As shown, Cu was added 2+ (3.3×10-8 -5.49945×10 -4 The fluorescence intensity gradually decreased (mol / L) until it stabilized. The results indicate that the probe P1-Cu... 2+ Fluorescence intensity in the system and Cu 2+ The concentration of Cu is inversely proportional to its concentration. 2+ The higher the concentration of Cu, the more pronounced the quenching phenomenon becomes. 2+ The concentration reached 5.4995 × 10⁻⁶. -4 At mol / L, the fluorescence intensity of probe P1 remained essentially stable.
[0081] Figure 9 The fluorescence intensity of probe P1 at 426 nm and Cu 2+ Linear fitting plot between, such as Figure 9 As shown, in Cu 2+ The concentration is 3.3 × 10⁻⁶. -8 -8.25×10 -7 In the mol / L range, probe P1-Cu 2+ The fluorescence intensity of the sample solution at 426 nm and Cu 2+ The concentration showed a good linear correlation, with a correlation coefficient R² = 0.96196 and a detection limit of 2.04 × 10⁻⁶. - 7 mol / L.
[0082] 5. Time response study of probe P1
[0083] The binding duration of a fluorescent probe to a target ion is an important indicator of its suitability for practical application. In this experiment, 5 μL Cu was added to the P1 solution. 2+ Fluorescence spectroscopy was performed on it every 1 minute to understand the relationship between probe P1 and Cu. 2+ The binding speed. For example... Figure 10 As shown, Cu was added 2+ The fluorescence intensity gradually decreased over time, reaching a stable value after 3 minutes, indicating that probe P1 reacts with Cu. 2+ They combine to form a complex, and the combination rate is relatively fast.
[0084] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.
[0085] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.
Claims
1. A benzimidazole Cu 2+ Fluorescent probe, characterized in that, The structure is as follows: 。 2. A benzimidazole Cu according to claim 1 2+ A method for preparing a fluorescent probe, characterized in that, Prepare according to the following steps: Step 1: Using anhydrous ethanol as a solvent, o-phenylenediamine and terephthalaldehyde undergo a nucleophilic addition reaction to further dehydrate. After the reaction is complete, a reaction solution is obtained. The reaction solution is then post-treated to obtain the intermediate 4-(1H-benzimidazol-2-yl)benzaldehyde. The synthesis route is as follows: ； Step 2: Using methanol as the reaction solvent, 4-(1H-benzimidazol-2-yl)benzaldehyde and 4-phenyl-3-thioaminourea undergo a nucleophilic addition reaction under the catalysis of glacial acetic acid to prepare benzimidazolium-based Cu. 2+ Fluorescent probe; The synthesis route is as follows: 。 3. A benzimidazole Cu according to claim 2 2+ A method for preparing a fluorescent probe, characterized in that, In step 1, the synthesis steps of intermediate 4-(1H-benzimidazol-2-yl)benzaldehyde are as follows: Anhydrous ethanol was added to o-phenylenediamine and terephthalaldehyde, and the solution changed from colorless to orange-red. The mixture was heated under reflux at 75-85℃ for 1-4 hours until the reaction was complete, and the reaction solution was obtained. After cooling, the pH was adjusted to 5.0-5.5 with NaHCO3, and the solution was rotated to evaporate to obtain the crude product. After separation and purification, the crude product was rotated to evaporate and dried to obtain the intermediate 4-(1H-benzimidazol-2-yl)benzaldehyde. The ratio of o-phenylenediamine, terephthalaldehyde, and ethanol is 4 mmol: 12 mmol: 50-60 mL.
4. A benzimidazole Cu according to claim 3 2+ A method for preparing a fluorescent probe, characterized in that, In step 1, the crude product is separated and purified twice by silica gel column chromatography. The eluent is dichloromethane and ethyl acetate in a volume ratio of 8-10:1, and the developing solvent is dichloromethane and ethyl acetate in a volume ratio of 3-6:
1.
5. A benzimidazole Cu according to claim 2 2+ A method for preparing a fluorescent probe, characterized in that, In step 2, benzimidazole Cu 2+ The synthesis steps of the fluorescent probe are as follows: Glacial acetic acid and methanol were added to 4-(1H-benzimidazol-2-yl)benzaldehyde and 4-phenyl-3-thioaminourea, and the mixture was heated under reflux at 70-75°C for 12-16 h. After the reaction was completed, post-treatment was performed to obtain benzimidazol-based Cu. 2+ Fluorescent probe; The ratio of 4-(1H-benzimidazol-2-yl)benzaldehyde, 4-phenyl-3-thioaminourea, glacial acetic acid and methanol is 1 mmol: 1 mmol: 0.15-0.2 mL: 30-35 mL.
6. A benzimidazole Cu according to claim 5 2+ A method for preparing a fluorescent probe, characterized in that, The post-processing steps in step 2 are as follows: After the reaction is complete, the solid is cooled, filtered, dissolved in methanol, allowed to crystallize twice, filtered, rotary evaporated, and dried to obtain benzimidazole Cu. 2+ Fluorescent probe.
7. A benzimidazole Cu according to claim 1 2+ Fluorescent probes in the preparation and detection of Cu 2+ Applications in materials.
8. The benzimidazole Cu according to claim 7 2+ Fluorescent probes in the preparation and detection of Cu 2+ The application of the material is characterized by, Using acetonitrile as the detection solution, the sample containing Cu was placed in the solution. 2+ The solution was added to a benzimidazole Cu 2+ An acetonitrile solution of the fluorescent probe was prepared, and fluorescence detection was performed at 333-600 nm.
9. The benzimidazole Cu according to claim 8 2+ Fluorescent probes in the preparation and detection of Cu 2+ The application of the material is characterized by... The detection wavelength is 426 nm.
10. The benzimidazole Cu according to claim 8 2+ Fluorescent probes in the preparation and detection of Cu 2+ The application of the material is characterized by... The Cu 2+ The concentration is ≥2.04×10 -7 mol / L.