A cellulose acetate-based 1,8-naphthalimide fluorescent probe for the detection of hydrazine, its preparation method and application.

Abstract

This invention discloses a cellulose acetate-based 1,8-naphthalenedimide fluorescent probe for detecting hydrazine, its preparation method, and its application. The invention uses 4-bromo-1,8-naphthalenedimide as a raw material, which undergoes a condensation reaction with 4-aminobutyric acid to obtain 4-(4-bromo-1,8-naphthalenedimide)butyric acid (BNA-B); BNA-B undergoes a coupling reaction with 4-formylphenylboronic acid to obtain 4-(4-(4-formylphenyl)-1,8-naphthalenedimide)butyric acid (FNA-B); compound FNA-B then undergoes an esterification reaction with cellulose acetate (CA) to obtain the cellulose acetate-based 1,8-naphthalenedimide fluorescent probe FNA-B-CA. This compound specifically recognizes hydrazine. Under 365 nm ultraviolet light irradiation, the addition of hydrazine to a DMF / H2O solution of FNA-B-CA changes the fluorescence color of the solution from bright blue to colorless, indicating a detection limit of 8.4 × 10⁻⁶ for hydrazine. ‑8 M has promising applications as a fluorescent probe for the detection of hydrazine.

Description

Technical Field

[0001] This invention belongs to the field of fluorescence detection technology, and relates to a cellulose acetate-based 1,8-naphthalimide fluorescent probe for detecting hydrazine, its preparation method, and its application. Background Technology

[0002] Hydrazine is a colorless, oily liquid with a pungent odor that fumes and emits an irritating odor when exposed to air. With strong nucleophilic and reducing properties, hydrazine is an important chemical raw material widely used in aerospace rocket and jet engine fuels, dyes, antioxidants, polymer crosslinking agents, pharmaceuticals, pesticides, and plastics. However, hydrazine is highly toxic, has high alkalinity, and good water solubility, posing a significant threat to environmental safety. It can enter the human body through inhalation, skin contact, and drug ingestion, damaging human DNA sequences and harming the lungs, liver, and central nervous system, causing irreversible and serious harm. Currently, methods for detecting hydrazine mainly include electrochemical methods, chemical titration, and spectrophotometry. These methods have several limitations: cumbersome operation, limited practicality, and low sensitivity. In contrast, fluorescent probe technology offers advantages such as ease of operation and high sensitivity.

[0003] Cellulose is a widely available and abundant natural polymer. Each glucose ring in cellulose contains three hydroxyl groups, which can undergo reactions such as oxidation, etherification, crosslinking, and esterification to achieve functional modification and applications of cellulose, endowing it with new properties. Cellulose acetate, an acetate ester of cellulose, is a derivative of cellulose and is more soluble in organic solvents than cellulose itself. Furthermore, it possesses advantages such as good biodegradability and mechanical properties, low cost, and non-toxicity. Therefore, cellulose acetate has been widely used in food packaging materials, biosensing, and electrochemistry in recent years. 1,8-Naphthalimide is a high-performance small molecule fluorophore commonly used in the field of fluorescent probes. However, these small molecule fluorescent probes have some drawbacks: high cytotoxicity, low quantum yield, and poor processability. Grafting small-molecule fluorescent probes onto cellulose chains yields cellulose-based macromolecular fluorescent probes. These probes not only possess the excellent properties of cellulose polymers themselves but also overcome many limitations of small-molecule fluorescent compounds. Furthermore, the stable chemical bonds between the small-molecule fluorophores and the cellulose backbone effectively address the issue of fluorescent molecule loss in materials prepared by physical mixing of small molecules with polymers. Therefore, the development of cellulose acetate-based macromolecular fluorescent probes is of great significance and holds broad application prospects in fields such as bioimaging, detection sensing, and information anti-counterfeiting. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the technical problem this invention aims to solve is to provide a cellulose acetate-based 1,8-naphthalenediimide fluorescent probe, FNA-B-CA, for the detection of hydrazine. The DMF / H₂O solution of this fluorescent probe emits bright blue fluorescence under 365 nm ultraviolet light irradiation, but the solution does not fluoresce upon the addition of hydrazine, thus it can be used for hydrazine detection. Another technical problem this invention aims to solve is to provide a method for preparing the above-mentioned cellulose acetate-based 1,8-naphthalenediimide fluorescent probe FNA-B-CA. Yet another technical problem this invention aims to solve is to provide an application of the above-mentioned cellulose acetate-based 1,8-naphthalenediimide fluorescent probe FNA-B-CA.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0006] A fluorescent probe FNA-B-CA based on cellulose acetate-based 1,8-naphthalimide for the detection of hydrazine has the following structural formula:

[0007]

[0008] The preparation method of the cellulose acetate-based 1,8-naphthalimide fluorescent probe includes the following steps:

[0009] (1) 4-Bromo-1,8-naphthalenedicarboxylic anhydride reacts with 4-aminobutyric acid to prepare compound BNA-B;

[0010] (2) Compound BNA-B undergoes a coupling reaction with 4-formylphenylboronic acid to prepare compound FNA-B;

[0011] (3) Compound FNA-B undergoes an esterification reaction with the hydroxyl groups on cellulose acetate to prepare cellulose acetate-based 1,8-naphthalimide fluorescent probe FNA-B-CA.

[0012] The preparation steps of compound BNA-B in step (1) are as follows:

[0013] 1) Add 1 mmol of 4-bromo-1,8-naphthalenedicarboxylic anhydride, 1-2 mmol of 4-aminobutyric acid and 20-40 mL of ethanol sequentially to a 50 mL single-necked flask equipped with a stirrer, thermometer and reflux condenser. Stir and reflux at 80 °C for 4-6 h. Monitor the reaction by TLC until it is complete and then stop the reaction.

[0014] 2) After the reaction was cooled to room temperature, the precipitated solid was filtered and washed with distilled water, and then dried under vacuum at 45°C for 24–36 h to obtain compound BNA-B.

[0015] The preparation steps of compound FNA-B in step (2) are as follows:

[0016] 1) Add 1 mmol of compound BNA-B, 20-30 mL of 1,4-dioxane, 2-3 mmol of 4-formylphenylboronic acid, and 5-10 mL of potassium carbonate aqueous solution (2 mol / L) to a 50 mL three-necked flask equipped with a stirrer, thermometer, and reflux condenser in sequence. React at 90 °C for 20-40 min under nitrogen atmosphere.

[0017] 2) Add 0.1–0.2 mmol of tetra(triphenylphosphine)palladium to the above reaction solution and continue the reaction for 10–14 h. Monitor the reaction by TLC until it is complete and then stop the reaction.

[0018] 3) After the reaction was completed, the solvent was evaporated, and dichloromethane was added for extraction three times. The organic phase was dried over anhydrous sodium sulfate, filtered, concentrated to obtain the crude product, and then purified by silica gel column chromatography (dichloromethane:methanol = 30:1) to obtain compound FNA-B.

[0019] The preparation steps of the fluorescent probe FNA-B-CA in step (3) are as follows:

[0020] 1) Add 0.6-0.8 g of cellulose acetate, 1-2 mmol of compound FNA-B, 0.4-0.6 mmol of 4-dimethylaminopyridine and 50-70 mL of DMF to a 100 mL three-necked flask equipped with a stirrer and thermometer. React in an ice bath for 20-40 min under nitrogen atmosphere.

[0021] 2) Add 2-3 mmol of dicyclohexylcarbodiimide dissolved in 5 mL of DMF to the above reaction solution and continue the reaction at room temperature for 36-48 h;

[0022] 3) After the reaction is complete, pour the reaction solution into 200 mL of distilled water. After filtration and washing with distilled water, the precipitate is dried under vacuum at 45 °C for 24–36 h to obtain the fluorescent probe FNA-B-CA.

[0023] The application of the cellulose acetate-based 1,8-naphthalimide fluorescent probe in the detection of hydrazine. The DMF / H₂O solution of this probe emits blue fluorescence under 365 nm ultraviolet light. Upon addition of hydrazine, the fluorescence color of the solution changes from blue to colorless, making it suitable for the detection of hydrazine.

[0024] Beneficial Effects: Compared with existing technologies, the advantages of this invention are as follows: Cellulose, as the most widely distributed and abundant natural polymer in nature, is readily available and inexpensive. 1,8-Naphthalimide is a high-performance fluorophore often used in the field of fluorescent probes. Grafting 1,8-naphthalimide derivatives onto cellulose chains yields cellulose-based fluorescent probes that not only possess the excellent properties of cellulose polymers themselves but also overcome many limitations of small-molecule fluorescent compounds. The resulting fluorescent probe FNA-B-CA exhibits good luminescence performance and structural stability. When hydrazine is added to the DMF / H2O solution of this probe under 365nm ultraviolet light irradiation, the fluorescence color of the solution gradually changes from blue to colorless, and the detection limit for hydrazine reaches 8.4 × 10⁻⁶. -8 M has promising applications as a fluorescent probe for the detection of hydrazine. Attached Figure Description

[0025] Figure 1 The infrared spectrum of CA, the infrared spectrum of the fluorescent probe FNA-B-CA, and the infrared spectrum of the compound FNA-B are shown below.

[0026] Figure 2 Fluorescence spectra of the fluorescent probe FNA-B-CA solution (DMF / H2O = 2:8) before and after the addition of hydrazine;

[0027] Figure 3 Fluorescence spectra of different analytes added to the fluorescent probe FNA-B-CA solution (DMF / H2O = 2:8);

[0028] Figure 4 Fluorescence spectra of fluorescent probe FNA-B-CA solution (DMF / H2O = 2:8) with different concentrations of hydrazine added. Detailed Implementation

[0029] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the examples in the specification.

[0030] Example 1

[0031] The synthesis of the fluorescent probe FNA-B-CA follows the reaction formula below:

[0032]

[0033] The specific steps are as follows:

[0034] 1) 1 mmol of 4-bromo-1,8-naphthalenedicarboxylic anhydride, 1.1 mmol of 4-aminobutyric acid, and 20 mL of ethanol were added sequentially to a 50 mL single-necked flask equipped with a stirrer, thermometer, and reflux condenser. The mixture was stirred and refluxed at 80 °C for 4 h. The reaction was monitored by TLC until it was complete, and then the reaction was stopped. After cooling to room temperature, the precipitated solid was filtered, washed with distilled water, and dried under vacuum at 45 °C for 24 h to obtain compound BNA-B with a yield of 90%. 1 H NMR (600MHz, DMSO-d6) δ: 11.97 (s, 1H), 8.50 (dd, J=16.6, 7.9Hz, 2H), 8.27 (d, J=7.8Hz, 1H), 8.16 (d, J= 7.8Hz, 1H), 7.94 (t, J=7.9Hz, 1H), 4.03 (t, J=6.9Hz, 2H), 2.27 (t, J=7.3Hz, 2H), 1.85 (p, J=7.1Hz, 2H). 13 CNMR (150MHz, DMSO-d6) δ: 174.48, 163.42, 163.37, 132.91, 131.92, 131.7 2, 131.30, 130.16, 129.44, 129.16, 128.73, 123.23, 122.46, 31.81, 23.38.

[0035] 2) To a 50 mL three-necked flask equipped with a stirrer, thermometer, and reflux condenser, add 1 mmol of compound BNA-B, 20 mL of 1,4-dioxane, 2 mmol of 4-formylphenylboronic acid, and 5 mL of potassium carbonate aqueous solution (2 mol / L). React at 90 °C for 20 min under nitrogen atmosphere. Then, add 0.1 mmol of tetrakis(triphenylphosphine)palladium to the above reaction solution and continue the reaction for 12 h, monitoring the reaction by TLC until complete. After the reaction, evaporate the solvent, extract three times with dichloromethane, dry the organic phase with anhydrous sodium sulfate, filter, concentrate to obtain the crude product, and then purify by silica gel column chromatography (dichloromethane:methanol = 30:1) to obtain compound FNA-B, with a yield of 52%. 1 H NMR (600MHz, DMSO-d6) δ: 12.02 (s, 1H), 10.16 (s, 1H), 8.53 (q, J=9.1, 8.5Hz, 2H), 8.19 (dd, J=8.2, 3.9Hz, 1H), 8.13 (d, J =7.8Hz, 2H), 7.85 (t, J = 7.8Hz, 2H), 7.79 (d, J = 7.8Hz, 2H), 4.11 (t, J = 6.9Hz, 2H), 2.35-2.30 (m, 2H), 1.94-1.87 (m, 2H). 13C NMR (150MHz, DMSO-d6) δ: 192.78, 173.86, 163.31, 163.08, 144.36, 143.95, 135.73, 132.34, 131.55, 131.35 , 131.14, 130.67, 130.53, 130.06, 129.67, 128.80, 127.96, 127.75, 127.60, 122.39, 121.84, 31.18, 22.81.

[0036] 3) Add 0.6 g CA, 1 mmol of compound FNA-B, 0.4 mmol of 4-dimethylaminopyridine and 50 mL of DMF to a 100 mL three-necked flask equipped with a stirrer and thermometer. React in an ice bath under nitrogen atmosphere for 30 min. Then add 2 mmol of dicyclohexylcarbodiimide dissolved in 5 mL of DMF to the above reaction solution and continue to react at room temperature for 48 h. After the reaction is completed, pour the reaction solution into 200 mL of distilled water. After the precipitate is filtered and washed with distilled water, it is dried under vacuum at 45 °C for 24 h to obtain the fluorescent probe FNA-B-CA.

[0037] The structure of the fluorescent probe FNA-B-CA was analyzed using FT-IR. Figure 1 The figures show the infrared spectra of CA, the fluorescent probe FNA-B-CA, and the compound FNA-B. As can be seen from the figures, CA and FNA-B-CA are at 3511 cm⁻¹. -1 A distinct characteristic absorption peak is observed at 1700 cm⁻¹, which corresponds to the stretching vibration absorption peak of the OH bonds in the cellulose chain. The fluorescent probe FNA-B-CA shows an absorption peak at 1700 cm⁻¹. -1 A new absorption peak appeared, which belongs to the stretching vibration absorption peak of C=O, indicating that CA and FNA-B are linked together through an esterification reaction. In addition, the fluorescent probe FNA-B-CA also showed some new peaks belonging to the characteristic peaks of the benzene ring, such as the skeletal vibration peaks of C=C (1590, 1516 cm⁻¹). -1 ) and the bending vibration peak of hydrocarbons (783 cm⁻¹) -1 Therefore, FT-IR analysis showed that the fluorescent probe FNA-B-CA was successfully prepared.

[0038] Example 2

[0039] The fluorescent probe FNA-B-CA was added to a DMF / H2O solution (DMF / H2O = 2:8, v / v) to prepare a solution with a concentration of 0.025 mg / mL. Its fluorescence emission spectrum was measured on a fluorescence spectrophotometer using a fluorescence spectrophotometric titration method. Figure 2As shown. The results indicate that in DMF / H2O solution, the fluorescent probe FNA-B-CA emits a strong fluorescence intensity at 432 nm, while the fluorescence intensity at 432 nm decreases sharply after the addition of hydrazine. (Excitation wavelength: 360 nm; excitation slit bandwidth: 10 nm; emission slit bandwidth: 3.5 nm).

[0040] The fluorescent probe FNA-B-CA was added to a DMF / H2O solution (DMF / H2O = 2:8, v / v) to prepare a solution with a concentration of 0.025 mg / mL. One portion was used as a blank sample, and the other portions were prepared by adding other analytes, with 1-15 representing Ca2+, B-CA, and C-CA, respectively. 2+ Mg 2+ Cu 2+ Fe 2+ Zn 2+ The fluorescence emission spectra of solutions containing isoniazid, 2,4-dinitrophenylhydrazine, phenylhydrazine, acetylhydrazine, formylhydrazine, glycine, valine, leucine, cysteine, and lysine were measured, and the results are as follows: Figure 3 As shown, the fluorescence intensity of the solution at 432 nm decreased sharply after the addition of hydrazine, while the fluorescence intensity at 432 nm changed very little when other analytes were added. This indicates that the fluorescent probe FNA-B-CA has good selectivity for the detection of hydrazine.

[0041] The fluorescent probe FNA-B-CA was added to a DMF / H2O solution (DMF / H2O = 2:8, v / v) to prepare a solution with a concentration of 0.025 mg / mL. The fluorescence emission spectra were measured after adding different concentrations of hydrazine (0-90 μM), as shown below. Figure 4 As shown in the figure, the results indicate that the fluorescence signal intensity of the fluorescent probe FNA-B-CA at 432 nm gradually decreased with increasing hydrazine concentration (0-90 μM), demonstrating that the fluorescent probe FNA-B-CA can be used to detect the concentration of hydrazine in solution, with a detection limit of 8.4 × 10⁻⁶. -8 M.

Claims

1. A method for preparing a cellulose acetate-based 1,8-naphthalimide fluorescent probe, characterized in that, Includes the following steps: (1) 4-Bromo-1,8-naphthalenedicarboxylic anhydride and 4-aminobutyric acid undergo a condensation reaction to produce 4-(4-bromo-1,8-naphthalenedimide)butyric acid, namely BNA-B; (2) BNA-B undergoes a coupling reaction with 4-formylphenylboronic acid to prepare 4-(4-(4-formylphenyl)-1,8-naphthalenedimide)butyric acid, i.e., FNA-B; (3) The carboxyl group on FNA-B undergoes an esterification reaction with the hydroxyl group on cellulose acetate to prepare a cellulose acetate-based 1,8-naphthalimide fluorescent probe, namely FNA-B-CA.

2. The method for preparing the cellulose acetate-based 1,8-naphthalimide fluorescent probe according to claim 1, characterized in that, The specific preparation steps of BNA-B in step (1) are as follows: 1) Add 1 mmol of 4-bromo-1,8-naphthalenedicarboxylic anhydride, 1-2 mmol of 4-aminobutyric acid and 20-40 mL of ethanol sequentially to a 50 mL single-necked flask equipped with a stirrer, thermometer and reflux condenser. Stir and reflux at 80 °C for 4-6 h. Monitor the reaction by TLC until it is complete and then stop the reaction. 2) After the reaction solution is cooled to room temperature, the precipitated solid precipitate is filtered, washed with distilled water, and then dried under vacuum at 45°C for 24–36 h to obtain compound BNA-B.

3. The method for preparing the cellulose acetate-based 1,8-naphthalimide fluorescent probe according to claim 1, characterized in that, The specific preparation steps of FNA-B in step (2) are as follows: 1) Add 1 mmol of compound BNA-B, 20-30 mL of 1,4-dioxane, 2-3 mmol of 4-formylphenylboronic acid and 5-10 mL of 2 mol / L potassium carbonate aqueous solution to a 50 mL three-necked flask equipped with a stirrer, thermometer and reflux condenser in sequence. React at 90 °C for 20-40 min under nitrogen atmosphere. 2) Add 0.1–0.2 mmol of tetra(triphenylphosphine)palladium to the above reaction solution and continue the reaction for 10–14 h. Monitor the reaction by TLC until it is complete and then stop the reaction. 3) After the reaction was completed, the solvent was evaporated, and dichloromethane was added for extraction three times. The organic phase was dried with anhydrous sodium sulfate, filtered, and concentrated to obtain the crude product, which was then purified by silica gel column chromatography to obtain compound FNA-B.

4. The method for preparing the cellulose acetate-based 1,8-naphthalimide fluorescent probe according to claim 1, characterized in that, The preparation steps of FNA-B-CA in step (3) are as follows: 1) Add 0.6-0.8 g of cellulose acetate, 1-2 mmol of compound FNA-B, 0.4-0.6 mmol of 4-dimethylaminopyridine and 50-70 mL of DMF to a 100 mL three-necked flask equipped with a stirrer and thermometer. React for 20-40 min under nitrogen atmosphere and ice bath. 2) Add 2-3 mmol of dicyclohexylcarbodiimide dissolved in 5 mL of DMF to the above reaction solution and continue the reaction at room temperature for 36-48 h; 3) After the reaction is complete, pour the reaction solution into 200 mL of distilled water. After filtration and washing with distilled water, the precipitate is dried under vacuum at 45 °C for 24–36 h to obtain the fluorescent probe FNA-B-CA.

5. The cellulose acetate-based 1,8-naphthalimide fluorescent probe prepared by the method described in claim 1.

6. The application of the cellulose acetate-based 1,8-naphthalimide fluorescent probe according to claim 5 in the detection of hydrazine.

7. The application according to claim 6, characterized in that, Under 365nm ultraviolet light irradiation, the DMF / H2O solution of cellulose acetate-based 1,8-naphthalimide fluorescent probes emits bright blue fluorescence. After the addition of hydrazine, the fluorescence color of the solution changes from blue to colorless.

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