A dithiophene ethanol hydrazine aluminum ion fluorescent probe and a preparation method thereof

Abstract

The application relates to a dithiophene glycol hydrazine aluminum ion fluorescent probe and a preparation method. The dithiophene glycol hydrazine aluminum ion fluorescent probe is prepared by carrying out an amidation reaction on 2,2-dithiophenyl glycolic acid methyl ester and hydrazine hydrate, and then carrying out an amine aldehyde condensation on 2-hydroxy-1-naphthaldehyde. The material ratio of 2,2-dithiophenyl glycolic acid methyl ester, hydrazine hydrate and methanol is 1g:2mL:16mL, the mass concentration of hydrazine hydrate is 40%-50%, the molar ratio of the intermediate 1 and 2-hydroxy-1-naphthaldehyde is 1:1, and the eluent is petroleum ether / ethyl acetate with a volume ratio of 1:4. The dithiophene glycol hydrazine aluminum ion fluorescent probe preparation method is simple, fast in response speed, strong in anti-interference ability, wide in pH application range, beneficial to convenient and trace detection of aluminum ions in an ecological environment and water, and has popularization and application values.

Description

Technical Field

[0001] This invention relates to a dithiophene glycolylhydrazine aluminum ion fluorescent probe and its preparation method, specifically belonging to the field of organic functional materials technology. Background Technology

[0002] Aluminum is the most abundant metallic element in the Earth's crust, playing a vital role in numerous fields such as food packaging, drinking water supply, manufacturing, and cookware. However, excessive aluminum intake can damage the human nervous system and induce various diseases, such as anemia, dementia, and gastrointestinal disorders, the most common being Alzheimer's disease. Therefore, highly sensitive detection of aluminum ions in environmental water bodies and organisms is of great significance for ecological environmental protection and human health.

[0003] Currently, aluminum ion detection technologies mainly involve spectrophotometry, electrochemical methods, atomic absorption spectrometry, and inductively coupled plasma atomic emission spectrometry. However, these methods are costly, complex, and have poor biocompatibility. Fluorescence analysis has attracted widespread attention due to its high sensitivity, low cost, simplicity, and short detection time. Most reported aluminum ion fluorescent probes exhibit poor water solubility and low specificity. Therefore, a dithiophene ethanol group with multiple sulfur and oxygen atoms was introduced into the probe molecule design. This group allows for more precise coordination with aluminum ions, resulting in more efficient identification. The introduction of hydroxyl groups further enhances water solubility. Therefore, designing and developing fluorescent probes with high selectivity and water solubility for aluminum ions is of significant importance and holds promising commercial applications. Summary of the Invention

[0004] To overcome the shortcomings of the prior art, the purpose of this invention is to provide a dithiophene glycolyl hydrazine aluminum ion fluorescent probe and its preparation method. This fluorescent probe can be used to detect aluminum ions in water and the environment, and has the characteristics of fast response, good selectivity, high sensitivity, simple operation, strong anti-interference ability, and wide pH range.

[0005] The purpose of this invention is to provide a fluorescent probe for efficient detection of aluminum ions and its preparation method. The chemical structural formula of a dithiophene glycolylhydrazine aluminum ion fluorescent probe is as follows:

[0006] .

[0007] A method for preparing a dithiophene glycolyl hydrazine aluminum ion fluorescent probe involves an amidation reaction of methyl 2,2-dithiophene glycolate with hydrazine hydrate, followed by an aminoaldehyde condensation reaction with 2-hydroxy-1-naphthaldehyde. The specific steps are as follows:

[0008] Step 1: Methyl 2,2-dithienyl glycolate and hydrazine hydrate were heated under reflux in methanol for 4-6 h. After the product was cooled to room temperature, methanol was removed by vacuum distillation. Then, ethyl acetate was added to extract the organic phase. The extract was washed with saturated brine, dried with anhydrous sodium sulfate, filtered and distilled under vacuum to obtain intermediate 1.

[0009] Step 2: Intermediate 1 and 2-hydroxy-1-naphthaldehyde were heated and refluxed in anhydrous ethanol for 4-6 h. The resulting white flocculent precipitate was filtered and purified by chromatography with eluent to obtain a dithiophene glycolylhydrazine aluminum ion fluorescent probe.

[0010] In step 1, the material ratio of methyl 2,2-dithienyl glycolate, hydrazine hydrate, and methanol is 1 g: 2 mL: 16 mL, wherein the mass concentration of hydrazine hydrate is 40% to 50%.

[0011] In step 2, the molar ratio of intermediate 1 and 2-hydroxy-1-naphthaldehyde is 1:1, and the eluent is a petroleum ether / ethyl acetate solvent with a volume ratio of 1:4.

[0012] The reaction equation for this invention is as follows:

[0013] ;

[0014] Where: 1 represents intermediate 1; NS represents dithiophene glycolylhydrazine aluminum ion fluorescent probe.

[0015] Method of using the aluminum ion fluorescent probe of the present invention:

[0016] The method of using the dithiophene glycolyl hydrazine aluminum ion fluorescent probe is to add a solution containing aluminum ions dropwise into a MeOH / H2O solution of the probe molecule NS. During the process, a change from no fluorescence to strong blue fluorescence is observed. However, no fluorescence change is observed when other cation solutions other than aluminum ions are added.

[0017] Specifically, a dilute solution of the probe molecule NS was placed in 21 5 mL centrifuge tubes, and Li was added dropwise to each tube. + Na + Mg 2 + Al 3+ K + Ca 2+ Cr 3+ Mn 2+ Fe 2+ Fe 3+ Co 2+ Ni 2+ Cu 2+ Zn 2+ Ag+ Cd 2+ Ba 2+ Hg 2+ Pb 2+ Ce 3+ Zr 4+ In aqueous solution, a dilute solution of the probe molecule NS was observed to change from no fluorescence to strong blue fluorescence in a centrifuge tube containing aluminum ions, while no fluorescence change was observed when other cation solutions were added.

[0018] 1. The molecular structure of the aluminum ion fluorescent probe of dithiophene glycolyl hydrazine of the present invention is synthesized for the first time. It has good ion selectivity, strong anti-interference ability, and high sensitivity detection is not affected by other common metal ions. It can effectively distinguish aluminum ions from other common metal ions.

[0019] 2. The preparation process and usage method of this invention are simple and applicable to a wide range of conditions. It can show good detection effect in a wide pH range from weak acid to weak base. The emission wavelength is 450 nm, which is a blue fluorescence visible to the naked eye. It has strong identification specificity, high sensitivity, and fast response speed. It can respond in a short time and detect sensitively and rapidly. It is beneficial for the convenient and trace detection of aluminum ions in the ecological environment and water bodies, and has a wide range of practical application prospects. Attached Figure Description

[0020] Figure 1 The proton NMR spectrum of the aluminum ion fluorescent probe of dithiopheneethanolhydrazide of this invention ( 1 H-NMR spectrum;

[0021] Figure 2 The image shows the UV absorption spectrum of the aluminum ion fluorescent probe of dithiophene glycolyl hydrazide in aqueous solution in response to aluminum ions according to the present invention.

[0022] Figure 3 The fluorescence emission spectrum of the aluminum ion fluorescent probe of dithiophene glycolyl hydrazide of the present invention in response to aluminum ions in an aqueous solution system is shown.

[0023] Figure 4 This is a graph showing the UV spectrum changes of the aluminum ion fluorescent probe of dithiophene glycolyl hydrazide of the present invention in an aqueous solution system for different concentrations of aluminum ions;

[0024] Figure 5 This is a curve showing the absorbance of the dithiophene glycolyl hydrazide aluminum ion fluorescent probe of the present invention at 452 nm and the corresponding aluminum ion concentration.

[0025] Figure 6 This is a columnar spectrum of the metal ion selectivity of the aluminum ion fluorescent probe of dithiophene glycolyl hydrazine in the presence of different metal ions.

[0026] Figure 7This is a graph showing the fluorescence intensity changes of the aluminum ion fluorescent probe of dithiophene glycolyl hydrazide under different pH conditions.

[0027] Figure 8 This is a graph showing the fluorescence intensity changes of the aluminum ion fluorescent probe of dithiophene glycolyl hydrazine of the present invention at different response times. Detailed Implementation

[0028] The present invention will now be described in detail with reference to the accompanying drawings, but it should be noted that the implementation of the present invention is not limited to the following embodiments.

[0029] Example 1

[0030] Synthesis of dithiophene glycolylhydrazine aluminum ion fluorescent probe

[0031] Synthesis of intermediate 1:

[0032] 2,2-Dithienyl glycolate methyl ester (2.5401 g, 10 mmol) was dissolved in 40 mL of methanol, and then 5 mL of hydrazine hydrate was added. The mixture was heated under reflux for 6 h at an oil bath temperature of 70 °C until the reaction was complete (the reaction progress was tracked by TLC). The reaction product was cooled to room temperature, and methanol was removed by vacuum distillation using a rotary evaporator. The organic phase was extracted with ethyl acetate, washed with saturated brine, and separated. The organic phase was then dried with anhydrous sodium sulfate and filtered. Finally, 1.9583 g of white solid powder intermediate 1 was obtained by vacuum distillation, with a yield of 77%.

[0033] Synthesis of the probe molecule NS:

[0034] Intermediate 1 (0.2543 g, 1 mmol) and 2-hydroxy-1-naphthaldehyde (0.1722 g, 1 mmol) were dissolved in 20 mL of ethanol and heated under reflux for 6 h at an oil bath temperature of 80 °C. The mixture was refluxed until the reaction was complete (TLC tracer). The reaction solution was cooled to room temperature, and a white flocculent precipitate formed. The crude product obtained by filtration was further separated by column chromatography (eluent: petroleum ether:ethyl acetate = 1:4) to obtain 0.3479 g of a white dithiophene glycolylhydrazine aluminum ion fluorescent probe (NS), with a yield of 85%. 1 H NMR (400MHz, DMSO- d 6) δ:12.78 (s, 1H), 12.12 (s, 1H), 9.77 (s, 1H), 8.25 ~ 8.07 (m,1H), 8.06 ~ 7.75 (m, 3H), 7.59 (s, 1H), 7.51 (s, 2H), 7.40 (s, 1H), 7.21 (s,3H), 7.02 (s,2H).

[0035] Example 2

[0036] The selectivity of the dithiophene glycolylhydrazine aluminum ion fluorescent probe for ultraviolet detection of aluminum ions.

[0037] Experimental conditions were controlled using MeOH / H2O (1:1, v / v) and HEPES (1 mmol / L, pH=7.4) buffer solutions.

[0038] The dithiophene glycolylhydrazine aluminum ion fluorescent probe was dissolved in MeOH solvent and diluted to 100 mL in a volumetric flask to prepare a 1 mmol / L solution, which is the ion detection solution.

[0039] Take 22 5 mL centrifuge tubes. Add 0.1 mL of 1 mmol / L ion detection solution, 1 mL of HEPES buffer, and 1.4 mL of MeOH solution to each tube. Use the solution in the first centrifuge tube as a blank control. Add 0.5 mL of 1 mol / L Li+ solution to each of the other 21 centrifuge tubes. + Na + Mg 2+ Al 3+ K + Ca 2+ Cr 3+ Mn 2+ Fe 2+ Fe 3+ Co 2+ Ni 2+ Cu 2+ Zn 2+ Ag + Cd 2+ Ba 2+ Hg 2+ Pb 2+ Ce 3+ Zr 4+ Aqueous solution. After allowing the sample solution in each centrifuge tube to stand for 2 min, transfer it to a 1 cm × 1 cm standard quartz cuvette and measure the change curve of its ultraviolet spectrum.

[0040] The effect of the dithiophene glycolyl hydrazine aluminum ion fluorescent probe on the ultraviolet detection of aluminum ions is as follows: Figure 2 As shown in the figure. The results indicate that the fluorescent probe molecule exhibits a significant ultraviolet absorption peak at 391 nm after binding with aluminum ions. The results demonstrate that the dithiophene glycolylhydrazine aluminum ion fluorescent probe involved in this invention has ultraviolet selectivity for aluminum ions.

[0041] Example 3

[0042] The selectivity of the dithiophene glycolylhydrazine aluminum ion fluorescent probe for the fluorescence detection of aluminum ions.

[0043] Experimental conditions were controlled using MeOH / H2O (1:1, v / v) and HEPES (1 mmol / L, pH=7.4) buffer solutions.

[0044] Take 22 5 mL centrifuge tubes. Add 0.1 mL of 1 mmol / L ion detection solution, 1 mL of HEPES buffer solution, and 1.4 mL of MeOH solution to each tube. Use the solution in the first centrifuge tube as the blank group. Add 0.5 mL of 1 mol / L Li+ solution to each of the other 21 centrifuge tubes. + Na + Mg 2+ Al 3+ K + Ca 2+ Cr 3+ Mn 2+ Fe 2+ Fe 3+ Co 2 + Ni 2+ Cu 2+ Zn 2+ Ag + Cd 2+ Ba 2+ Hg 2+ Pb 2+ Ce 3+ Zr 4+ Aqueous solution. After allowing the sample solution in each centrifuge tube to stand for 2 min, it was transferred to a 1 cm × 1 cm standard quartz cuvette, and the fluorescence spectrum change curves were measured. The excitation wavelength was selected as 391 nm, and the maximum emission wavelength was 452 nm.

[0045] The fluorescence detection effect of the dithiophene glycolyl hydrazine aluminum ion fluorescent probe on aluminum ions is as follows: Figure 3 As shown in the figure. The results indicate that the fluorescent probe molecule exhibits significant fluorescence enhancement (approximately 77-fold increase) at 452 nm when bound to aluminum ions. These results demonstrate that the dithiophene glycolylhydrazine aluminum ion fluorescent probe described in this invention exhibits highly sensitive fluorescence changes in response to aluminum ions.

[0046] Example 4

[0047] Quantitative UV detection of aluminum ions using a dithiophene glycolylhydrazine aluminum ion fluorescent probe.

[0048] Experimental conditions were controlled using MeOH / H2O (1:1, v / v) and HEPES (1 mmol / L, pH=7.4) buffer solutions.

[0049] Weigh 0.0375 g Al(NO3)3·9 H2O, dissolve it in 30 mL of deionized water, transfer it to a 100 mL volumetric flask, add water to make up to the final volume, and prepare an aluminum ion aqueous solution with a concentration of 1 mmol / L.

[0050] The sample solutions were divided into 11 groups in 5 mL centrifuge tubes. Each group of tubes contained 0.06 mL of 1 mmol / L ion detection solution, 1.44 mL of MeOH solution, and then 1 eq to 8 eq of aluminum ion aqueous solution (0.06 mL to 0.48 mL). Finally, 1.44 mL to 1.02 mL of HEPES buffer solution was added to ensure a MeOH:H₂O ratio of 1:1 (v / v). After standing for 2 min, each sample solution was transferred to a 1 cm × 1 cm standard quartz cuvette, and its UV spectral changes were measured. Figure 4 This is the UV spectrum of the probe compound NS involved in this invention in an aqueous solution system as a function of aluminum ion concentration. The fitting curve (e.g., [image of the curve is missing]) is obtained by fitting the UV intensity at 391 nm with the corresponding aluminum ion equivalent ratio. Figure 5 As shown in the figure, the aluminum ion fluorescent probe of dithiophene ethanol hydrazine involved in this invention can quantitatively detect the aluminum ion concentration in an aqueous solution system.

[0051] Example 5

[0052] Ion interference-resistant detection using aluminum dithiophene glycolylhydrazine ion fluorescent probe.

[0053] Experimental conditions were controlled using MeOH / H2O (1:1, v / v) and HEPES (1 mmol / L, pH=7.4) buffer solutions.

[0054] The sample solutions were divided into two groups, A and B, with 21 samples in each group. In group A, each centrifuge tube contained 0.1 mL of a 1 mmol / L ion detection solution, 1 mL of HEPES buffer, and 1.4 mL of MeOH solution. The solution in the first centrifuge tube served as a blank. The other 20 centrifuge tubes contained 0.5 mL of a 1 mol / L Li+ solution. + Na + Mg2+ Al 3+ K + Ca 2+ Cr 3+ Mn 2+ Fe 2+ Fe 3+ Co 2+ Ni 2+ Cu 2+ Zn 2+ Ag + Cd 2+ Ba 2+ Hg 2+ Pb 2+ Ce 3+ Zr 4+ Aqueous solutions. In Group B, each centrifuge tube contained 0.1 mL of a 1 mmol / L ion detection solution, 0.5 mL of HEPES buffer solution, 0.5 mL of a 1 mmol / L aluminum ion aqueous solution, and 1.4 mL of MeOH solution. The solution in the first centrifuge tube served as a blank. The other 20 centrifuge tubes contained 0.5 mL of a 1 mol / L Li₂O₃ solution. + Na + Mg 2+ Al 3+ K + Ca 2+ Cr 3+ Mn 2+ Fe 2+ Fe 3+ Co 2+ Ni 2+ Cu 2+ Zn 2+ Ag + Cd 2+ Ba 2+ Hg 2+ Pb 2+ Ce 3+ Zr 4+ Aqueous solution. After the sample solution was allowed to stand for 2 minutes, each sample solution was transferred to a 1 cm × 1 cm standard quartz cuvette, and its fluorescence intensity value at the maximum emission wavelength of 452 nm was measured. Figure 6 This is a columnar spectrum of the fluorescent probe molecule NS according to the present invention, in the presence of different metal ions. This result indicates that the dithiophene glycolyl hydrazine aluminum ion fluorescent probe of the present invention has strong anti-interference ability in the presence of different metal ions.

[0055] Example 6

[0056] Effect of pH on the recognition of aluminum ions by a dithiophene glycolylhydrazide fluorescent probe

[0057] Experimental conditions were controlled using MeOH / H2O (1:1, v / v) and HEPES (1 mmol / L, pH=7.4) buffer solutions.

[0058] Eleven groups of aqueous solutions with different pH values ​​ranging from 2 to 12 were prepared using NaOH solution, HCl solution, and HEPES buffer solution, with pH gradients measured by a pH meter.

[0059] The sample solutions were divided into two groups, C and D, with 11 samples in each group. In group C, each centrifuge tube contained 0.1 mL of a 1 mmol / L ion detection solution, 1.4 mL of MeOH solution, and 1.5 mL of an aqueous solution with a pH range of 2–12. In group D, each centrifuge tube contained 0.1 mL of a 1 mmol / L ion detection solution, 0.3 mL of a 1 mmol / L aluminum ion aqueous solution, 1.4 mL of MeOH solution, and 1.2 mL of an aqueous solution with a pH range of 2–12. After standing for 2 min, each sample solution was transferred to a 1 cm × 1 cm standard quartz cuvette, and the fluorescence intensity was measured at the maximum emission wavelength of 452 nm. Figure 7 This diagram shows the fluorescence intensity changes of the dithiophene glycolyl hydrazine aluminum ion fluorescent probe of the present invention under different pH conditions. The results indicate that the dithiophene glycolyl hydrazine aluminum ion fluorescent probe of the present invention exhibits strong fluorescence changes at pH values ​​between 4 and 10, and this fluorescent probe can be well applied to the detection of aluminum ions under different pH conditions.

[0060] Example 7

[0061] Response time detection of aluminum ion fluorescent probes for dithiophene glycolylhydrazine

[0062] Experimental conditions were controlled using MeOH / H2O (1:1, v / v) and HEPES (1 mmol / L, pH=7.4) buffer solutions.

[0063] Take a 1 cm × 1 cm standard quartz cuvette, add 0.1 mL of 1 mmol / L ion detection solution, 1.2 mL of HEPES buffer solution, 1.4 mL of MeOH solution, and 0.3 mL of aluminum ion aqueous solution to the cuvette, and immediately place the cuvette into a fluorescence spectrometer for time-fluorescence value detection. Figure 8 This diagram shows the fluorescence intensity changes of the aluminum dithiophene glycol hydrazide fluorescent probe of the present invention at different response times. The results indicate that the aluminum dithiophene glycol hydrazide fluorescent probe of the present invention begins to respond within 30 s and reaches its peak fluorescence value at 240 s.

Claims

1. A fluorescent probe for dithiophene glycolylhydrazine aluminum ions, characterized in that: The chemical structural formula of the dithiophene glycolylhydrazine aluminum ion fluorescent probe is as follows: 。 2. A method for preparing a dithiophene glycolylhydrazine aluminum ion fluorescent probe, characterized in that: The preparation method involves an amidation reaction of methyl 2,2-dithienyl glycolate with hydrazine hydrate, followed by an amino-aldehyde condensation reaction with 2-hydroxy-1-naphthaldehyde. The specific steps include: Step 1: Methyl 2,2-dithienyl glycolate and hydrazine hydrate were heated under reflux in methanol for 4-6 h. After the product was cooled to room temperature, methanol was removed by vacuum distillation. Then, ethyl acetate was added to extract the organic phase. The extract was washed with saturated brine, dried with anhydrous sodium sulfate, filtered and distilled under vacuum to obtain intermediate 1. Step 2: Intermediate 1 and 2-hydroxy-1-naphthaldehyde were heated and refluxed in anhydrous ethanol for 4-6 h. The resulting white flocculent precipitate was filtered and purified by chromatography with eluent to obtain a dithiophene glycolylhydrazine aluminum ion fluorescent probe.

3. The method for preparing a dithiophene glycolylhydrazine aluminum ion fluorescent probe according to claim 2, characterized in that: In step 1, the material ratio of methyl 2,2-dithienyl glycolate, hydrazine hydrate, and methanol is 1 g: 2 mL: 16 mL, wherein the mass concentration of hydrazine hydrate is 40% to 50%.

4. The method for preparing a dithiophene glycolylhydrazine aluminum ion fluorescent probe according to claim 2, characterized in that: In step 2, the molar ratio of intermediate 1 and 2-hydroxy-1-naphthaldehyde is 1:1, and the eluent is a petroleum ether / ethyl acetate solvent with a volume ratio of 1:4.

Images