Colorimetric-fluorescent dual-channel near-infrared probe for H2S specific detection, preparation method and application of colorimetric-fluorescent dual-channel near-infrared probe

Abstract

The invention discloses a colorimetric-fluorescent dual-channel near-infrared probe for H2S specific detection, and a preparation method and application thereof, and belongs to the field of chemical analysis and detection. The preparation method comprises the following steps: firstly, preparing a compound 1 by taking anhydrous N, N-dimethylformamide, dichloromethane, phosphorus tribromide and cyclohexanone as reaction raw materials; reacting the compound 1, cesium carbonate and 2-hydroxy-4-methoxybenzaldehyde to prepare a compound 2; secondly, dropwise adding boron tribromide into a dichloromethane solution in which the compound 2 is dissolved, and reacting to obtain a compound 3; the preparation method comprises the following steps: enabling 3-hydroxy-3-methyl-2-butanone, malononitrile and sodium ethoxide to react to obtain TCF; thirdly, the compound 3 and TCF are subjected to a dissolution reaction, and TEC-OH is obtained; and finally, dropwise adding a dichloromethane solution containing 2, 4-dinitrofluorobenzene into a dichloromethane solution containing TEC-OH and triethylamine, and reacting to obtain the probe TEC-H2S. The colorimetric-fluorescent near-infrared probe TEC-H2S is successfully designed and synthesized on the basis of an intramolecular charge transfer (ICT) mechanism and is used for specific detection of H2S, and a sensing technology with a great application prospect is provided for H2S detection.

Description

Technical Field

[0001] This invention belongs to the field of chemical analysis and detection, and relates to a colorimetric-fluorescence dual-channel near-infrared probe for specific detection of H2S, its preparation method and application. Background Technology

[0002] Hydrogen sulfide (H2S) is considered a potential energy storage medium because it can release hydrogen gas through decomposition reactions. It is widely present in underground environments and is also a common byproduct of various industrial processes such as leather tanning, food processing, papermaking, and oil refining. However, it is a colorless and highly toxic gas, and has become a significant pollutant in aquatic systems, causing mass mortality of aquatic organisms and severely disrupting the underwater ecological balance. Furthermore, low concentrations of H2S can irritate the eyes and lungs and cause olfactory fatigue; high concentrations can lead to loss of consciousness, respiratory failure, and even death. Therefore, establishing accurate and convenient H2S detection methods is of great significance for ensuring safe production and achieving comprehensive environmental safety monitoring.

[0003] In recent years, fluorescent probe detection methods have attracted much attention from researchers. Compared with traditional H2S detection methods such as electrochemical analysis, colorimetric determination, gas chromatography, and chemiluminescence (CL), fluorescent probe methods have significant advantages such as high sensitivity, good selectivity, simple operation, low cost, and real-time non-invasive detection. Based on this, a series of H2S fluorescent probes designed through different mechanisms such as reduction reactions, thiolysis reactions, metal substitution reactions, and disulfide bond exchange reactions have been successfully developed. Although existing probes have achieved good detection performance, they still generally suffer from problems such as short emission wavelength, small Stokes shift, high detection limit, and insufficient selectivity, which limit their application in practical sample detection. More importantly, background fluorescence interference remains a key factor restricting the improvement of the performance of these probes. Near-infrared (NIR) fluorescent probes, with their characteristics of weak light scattering, strong tissue penetration, and low autofluorescence, can significantly reduce background interference in environmental and biological samples, providing an effective way to solve this problem. Furthermore, fluorescent probes with clear colorimetric signals can be directly observed for color changes with the naked eye, thus enabling naked-eye detection without instruments and further enhancing their potential for field applications.

[0004] Therefore, developing novel colorimetric-fluorescence dual-channel near-infrared fluorescent probes is of great research significance and application prospect for achieving convenient, highly sensitive and reliable H2S detection. Summary of the Invention

[0005] To address the shortcomings of existing H2S detection methods, this invention constructs a novel colorimetric-fluorescence dual-channel near-infrared probe using xanthracene as the basic framework and 2,4-dinitrophenyl (DNP) as the specific recognition group. This probe exhibits high selectivity, high sensitivity, and good stability, enabling specific quantitative analysis and visual detection of H2S.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: The primary objective of the present invention is to provide a colorimetric-fluorescence dual-channel near-infrared probe for specific detection of H2S, the structural formula of which is as follows:

[0007]

[0008] Another object of the present invention is to provide a method for preparing the colorimetric-fluorescence dual-channel near-infrared probe for specific detection of H2S, the preparation and synthesis route of which is as follows:

[0009]

[0010] The preparation method includes the following steps:

[0011] Step (1): Compound 1 was prepared using anhydrous N,N-dimethylformamide (DMF), dichloromethane (CH2Cl2), phosphorus tribromide (PBr3), and cyclohexanone as reactants;

[0012] Step (2): Compound 1, cesium carbonate Cs2CO3 and 2-hydroxy-4-methoxybenzaldehyde were added to organic solvent A and reacted under stirring. After post-treatment, compound 2 was obtained.

[0013] Step (3): At 0 °C, boron tribromide (BBr3) was slowly added dropwise to a dichloromethane solution containing compound 2; the reaction was carried out with stirring, and the compound 3 was obtained after post-treatment.

[0014] Step (4): At 0°C, 3-hydroxy-3-methyl-2-butanone, malononitrile and sodium ethoxide are dissolved in organic solvent B to obtain a mild solution, which is then heated and reacted to obtain TCF.

[0015] Step (5): Compound 3 and TCF are dissolved in organic solvent C and reacted under inert gas protection. After the reaction is completed, post-treatment is performed to obtain TEC-OH.

[0016] Step (6): Under the protection of an inert gas at 0°C, slowly add a dichloromethane solution B containing 2,4-dinitrofluorobenzene to a dichloromethane solution A containing TEC-OH and triethylamine; then heat the reaction solution to carry out the reaction, and post-process to obtain the probe TEC-H2S.

[0017] The specific preparation method is as follows:

[0018] Step (1): At 0°C, phosphorus tribromide (PBr3) was slowly added dropwise to a mixed solution of anhydrous N,N-dimethylformamide (DMF) and dichloromethane (CH2Cl2). The solution was then heated to 10–40°C to form a white suspension, and cyclohexanone was added dropwise. The reaction was stirred at 10–40°C for 8–16 hours. After the reaction was complete, the mixture was poured into ice water, and the pH was adjusted to neutral with sodium bicarbonate (NaHCO3) solid. The mixture was then extracted multiple times with dichloromethane (CH2Cl2), and the organic phase was collected and concentrated to obtain a yellow oily substance, compound 1.

[0019] Furthermore, the volume ratio of anhydrous N,N-dimethylformamide (DMF) to dichloromethane (CH2Cl2) in the mixed solution is 1:2 to 1:5. 0.5 to 1.5 mL of phosphorus tribromide (PBr3) and 0.2 to 0.8 mL of cyclohexanone are added to every 10.0 mL of the mixed solution.

[0020] Step (2): Compound 1, cesium carbonate (Cs₂CO₃), and 2-hydroxy-4-methoxybenzaldehyde were added to organic solvent A to dissolve the mixture, and the mixture was stirred at 10–40°C for 8–16 hours. After the reaction was completed, the mixture was quenched with water, extracted multiple times with dichloromethane (CH₂Cl₂), and the organic phase was collected and concentrated to obtain the crude product. The crude product was recrystallized from ethyl acetate to obtain a yellow solid, which is compound 2.

[0021] Furthermore, the organic solvent A includes N,N-dimethylformamide (DMF), dichloromethane (CH2Cl2), and ethanol (CH3CH2OH). Each 15.0 mL of organic solvent A contains 2.0–6.0 g of compound 1, 2.00–6.00 g of cesium carbonate (Cs2CO3), and 0.50–1.50 g of 2-hydroxy-4-methoxybenzaldehyde.

[0022] Step (3): Boron tribromide (BBr3) was slowly added dropwise to a dichloromethane (CH2Cl2) solution containing compound 2 at 0 °C. The reaction solution was then heated to 10–40 °C and stirred for 8–16 hours. After the reaction was complete, water was added to quench the reaction, and the mixture was extracted multiple times with dichloromethane (CH2Cl2). The organic phase was collected and concentrated to obtain the crude product. Finally, the crude product was purified by silica gel column chromatography using a mixed solvent of dichloromethane and methanol as washing agent to obtain the orange solid, which is compound 3.

[0023] Furthermore, 2.00~9.00 g of boron tribromide (BBr3) and 0.50~1.50 g of compound 2 are added to each 10.0 mL of dichloromethane (CH2Cl2) solution.

[0024] Step (4): At 0°C, 3-hydroxy-3-methyl-2-butanone, malononitrile, and sodium ethoxide are dissolved in organic solvent B to obtain a mild solution. The solution is then heated at 60-100°C for 0.5-2.5 hours. After the reaction solution cools to room temperature, the precipitate is collected by filtration to obtain a grayish-white solid, TCF.

[0025] Furthermore, the organic solvent B includes ethanol and N,N-dimethylformamide. Each 6.0 mL of organic solvent B contains 0.50-1.50 g of 3-hydroxy-3-methyl-2-butanone, 0.50-1.50 g of malononitrile, and 0.05-0.30 g of sodium ethoxide.

[0026] Step (5): Compound 3 and TCF were dissolved in organic solvent C and reacted under inert gas protection at 60-100°C for 8-16 hours with stirring. After the reaction was completed, the mixture was cooled to room temperature and filtered to obtain the crude product. The crude product was then purified by silica gel column chromatography using a mixed solvent of dichloromethane and methanol as washing agent to obtain a dark green solid, namely compound TEC-OH.

[0027] Furthermore, the organic solvent C includes ethanol and N,N-dimethylformamide, and the inert gas includes nitrogen and argon. The molar ratio of compound 3 to TCF is 1:1 to 1:3.

[0028] Step (6): Under inert gas protection at 0°C, a solution B of dichloromethane (CH2Cl2) containing 2,4-dinitrofluorobenzene was slowly added dropwise to dichloromethane (CH2Cl2) A containing TEC-OH and triethylamine. The reaction solution was then heated to 10–40°C and stirred for 8–16 hours. After the reaction was complete, the solvent was removed by concentration to obtain the crude product. The crude product was then purified by silica gel column chromatography using a mixed solvent of dichloromethane and methanol as washing agent to obtain the dark green solid product, namely the probe TEC-H2S.

[0029] Furthermore, the inert gas includes nitrogen and argon. The volume ratio of dichloromethane (CH2Cl2) solution A to dichloromethane (CH2Cl2) solution B is 5:1 to 10:1. 0.10 to 1.00 g of TEC-OH and 0.10 to 1.00 g of triethylamine are added to every 30.0 mL of dichloromethane (CH2Cl2) solution A. 0.10 to 0.50 g of 2,4-dinitrofluorobenzene is added to every 3.0 mL of dichloromethane (CH2Cl2) solution B.

[0030] Another object of the present invention is to provide the application of the colorimetric-fluorescence dual-channel near-infrared probe for specific detection of H2S. Specifically:

[0031] The colorimetric-fluorescence dual-channel near-infrared probe is used for the detection of H2S in water bodies. It is used for highly sensitive and visual detection of trace H2S in environmental water samples. Specifically, it achieves qualitative and quantitative analysis of H2S through a dual response mechanism of colorimetric and fluorescence signals.

[0032] The colorimetric-fluorescence dual-channel near-infrared probe loaded on the test paper is used for the rapid, sensitive, and real-time detection of trace H2S in water and gas. Specifically, by observing the color changes of different concentrations of H2S in water and gas environments through the probe test paper, it is possible to achieve low-cost, convenient, and visual detection of H2S.

[0033] The beneficial effects of this invention are as follows:

[0034] (1) The fluorescent probe molecule of this invention is constructed with xanthracene modified with a strong electron-withdrawing group tricyanofuran (TFC) as the basic backbone and 2,4-dinitrophenyl (DNP) as the specific recognition group. Under the shielding effect of DNP, the intramolecular charge transfer (ICT) process of the probe is inhibited, resulting in its fluorescence quenching state. In the presence of H2S, the probe molecule first undergoes nucleophilic attack by H2S, undergoes thiolysis, releases a strongly electron-donating hydroxyl group, and then forms a conjugated large π structure with a significant push-pull electron effect, which restores the ICT process, thereby producing strong fluorescence in the 783 nm near-infrared region and exhibiting a large Stokes shift of 103 nm. That is, the probe has the advantages of long emission wavelength (783 nm), large Stokes shift (103 nm), high sensitivity (detection limit up to 81.79 nM), and excellent selectivity and anti-interference ability.

[0035] (2) When the probe molecule of the present invention is used to detect H2S in solution, the solution color changes from blue to cyan, which can realize the visual detection of H2S.

[0036] (3) The probe molecule of the present invention is applied to H2S detection, with a wide detection range, good stability, high sensitivity, a detection limit as low as 81.79 nM, and strong specificity, and is effective for various common metal ions (K). + Na + NH4 + Ba 2+ Zn 2+ Ca 2+ Mg 2+ ,Fe 2+ Fe 3+ , ), inorganic anions (.Cl - , Br - , I - NO2 - NO3 -, ClO - HPO4 - SCN - SO3 2- HSO4 - HCO3 - CO3 2- SO4 2- S2O3 2- C2O4 2- The lack of response and interference from small organic molecules (Cys, Ala) indicates that the probe molecules of this invention can be applied to the sensitive and specific detection of H2S.

[0037] (4) The probe molecules of the present invention are loaded on the test paper and can quickly show obvious color changes in water and gas H2S. It can be used as a low-cost portable tool for the visual semi-quantitative detection of water and gas H2S. Attached Figure Description

[0038] Figure 1 This is the proton NMR spectrum of the colorimetric-fluorescence dual-channel near-infrared probe used for H2S specific detection according to the present invention.

[0039] Figure 2 This is a high-resolution mass spectrum of the colorimetric-fluorescence dual-channel near-infrared probe used for H2S specific detection according to the present invention.

[0040] Figure 3 The absorption and fluorescence spectra of the colorimetric-fluorescence dual-channel near-infrared probe for H2S specific detection of this invention before and after reaction with H2S are shown. Figure 3 (a) in the diagram is the absorption spectrum; Figure 3 (b) in the image is the fluorescence spectrum.

[0041] Figure 4 The fluorescence spectrum and linear relationship diagram of the colorimetric-fluorescence dual-channel near-infrared probe for H2S specific detection of the present invention after reacting with different concentrations of H2S; Figure 4 (a) in the image is the fluorescence spectrum; Figure 4 (b) in the diagram is a linear relationship graph.

[0042] Figure 5 The images show the fluorescence spectra of the colorimetric-fluorescence dual-channel near-infrared probe for H2S specific detection in this invention, along with the fluorescence spectra of H2S and different analytes, and the anti-interference detection results. Figure 5 (a) in the image is the fluorescence spectrum; Figure 5 (b) in the figure shows the anti-interference detection results.

[0043] Figure 6The images show the color change of the colorimetric-fluorescence dual-channel near-infrared probe test paper for H2S specific detection in this invention with H2S solution of different concentrations and H2S gas of different concentrations. Figure 6 (a) in the figure shows the color change of the colorimetric-fluorescence dual-channel near-infrared probe test paper with H2S solutions of different concentrations; Figure 6 (b) in the figure shows the color changes of H2S gas at different concentrations. Detailed Implementation

[0044] The present invention will be further described in detail below with reference to examples, but the embodiments of the present invention are not limited thereto.

[0045] Example 1: Preparation of a colorimetric-fluorescence dual-channel near-infrared probe for H2S specific detection.

[0046] Step (1): Phosphorus tribromide (0.6 mL, 6.4 mmol) was slowly added dropwise to a solution of N,N-dimethylformamide (4.0 mL, 52.0 mmol) and dichloromethane (8.0 mL) at 0°C. The solution was then heated to 10°C and stirred for 30 minutes to form a white suspension. Cyclohexanone (0.3 mL, 2.9 mmol) was added dropwise, and the mixture was stirred at 10°C for 16 hours. After the reaction was complete, the mixture was poured into ice water, and the pH was adjusted to neutral with sodium bicarbonate. The mixture was then extracted multiple times with dichloromethane, the organic phases were combined, dried over anhydrous sodium sulfate, and concentrated to give a yellow oil and compound 1.

[0047] Step (2): Compound 1 (4.54 g, 24.0 mmol), cesium carbonate (2.00 g, 6.1 mmol), and 2-hydroxy-4-methoxybenzaldehyde (0.50 g, 3.3 mmol) were added sequentially to a round-bottom flask. Dichloromethane (15.0 mL) was added to dissolve the mixture, and the mixture was stirred at 10°C for 16 hours. After the reaction was completed, the mixture was quenched with water, extracted multiple times with dichloromethane, and the organic phases were combined, dried over anhydrous sodium sulfate, and concentrated to obtain the crude product. The crude product was recrystallized from ethyl acetate to obtain a yellow solid, namely compound 2 (0.37 g, 46%).

[0048] Step (3): Boron tribromide (2.00 g, 8.0 mmol) was slowly added dropwise to a solution of dichloromethane (10.0 mL) containing compound 2 (0.50 g, 2.1 mmol) at 0°C. The reaction solution was then heated to 10°C and stirred for 16 hours. After the reaction was completed, the mixture was quenched with water, extracted multiple times with dichloromethane, and the organic phases were combined, dried over anhydrous sodium sulfate, and concentrated to obtain the crude product. The crude product was then purified by silica gel column chromatography (dichloromethane:methanol = 30:1~10:1, v / v) to obtain an orange solid, compound 3 (0.29 g, 60%).

[0049] Step (4): Dissolve 0.50 g (5.0 mmol) of 3-hydroxy-3-methyl-2-butanone, 0.50 g (7.6 mmol) of malononitrile, and 0.05 g (0.8 mmol) of sodium ethoxide in 6.0 mL of ethanol. Stir the mixture in an ice bath for 2 hours, then heat to 60°C for 2.5 hours. After the reaction solution cools to room temperature, filter and collect the precipitate to obtain a grayish-white solid, TCF (0.29 g, 28%).

[0050] Step (5): Compound 3 (0.57 g, 2.5 mmol) and TCF (0.49 g, 2.5 mmol) were dissolved in N,N-dimethylformamide (50.0 mL), and the mixture was stirred at 60°C for 16 hours under a nitrogen atmosphere. After the reaction was completed, the mixture was cooled to room temperature and filtered to obtain the crude product. The crude product was then purified by silica gel column chromatography (dichloromethane:methanol = 25:1~10:1, v / v) to obtain a dark green solid, namely compound TEC-OH (0.56 g, 55%).

[0051] Step (6): Under a nitrogen atmosphere, a solution of 3.0 mL of dichloromethane containing 0.10 g (0.2 mmol) of 2,4-dinitrofluorobenzene (0.10 g, 0.5 mmol) was slowly added dropwise to a solution of 30.0 mL of dichloromethane containing TEC-OH (0.10 g, 0.2 mmol) and triethylamine (0.10 g, 1.0 mmol). The reaction solution was then heated to 10°C and stirred for 16 hours. After the reaction was completed, the solvent was removed by concentration to obtain the crude product. The crude product was finally purified by silica gel column chromatography (dichloromethane:methanol = 100:0~100:1, v / v) to obtain a dark green solid product, TEC-H2S (0.07 g, 61%).

[0052] Example 2: Preparation of a colorimetric-fluorescence dual-channel near-infrared probe for H2S specific detection.

[0053] Step (1): At 0°C, phosphorus tribromide (1.9 mL, 20.1 mmol) was slowly added dropwise to a solution of N,N-dimethylformamide (4.0 mL, 52.0 mmol) and dichloromethane (15.0 mL). The solution was then heated to 25°C and stirred for 30 minutes to form a white suspension. Cyclohexanone (1.2 mL, 11.6 mmol) was added dropwise, and the mixture was stirred at 25°C for 12 hours. After the reaction was complete, the mixture was poured into ice water, and the pH was adjusted to neutral with sodium bicarbonate. The mixture was then extracted multiple times with dichloromethane, the organic phases were combined, dried over anhydrous sodium sulfate, and concentrated to give a yellow oily substance, compound 1.

[0054] Step (2): Compound 1 (4.54 g, 24.0 mmol), cesium carbonate (3.92 g, 12.0 mmol), and 2-hydroxy-4-methoxybenzaldehyde (0.91 g, 6.0 mmol) were added sequentially to a round-bottom flask. N,N-dimethylformamide (15.0 mL) was added to dissolve the mixture, and the mixture was stirred at 25°C for 12 hours. After the reaction was complete, the mixture was quenched with water, extracted multiple times with dichloromethane, and the organic phases were combined, dried over anhydrous sodium sulfate, and concentrated to obtain the crude product. The crude product was recrystallized from ethyl acetate to obtain a yellow solid, compound 2 (0.87 g, 60%).

[0055] Step (3): Boron tribromide (7.24 g, 29.0 mmol) was slowly added dropwise to a solution of dichloromethane (10.0 mL) containing compound 2 (1.21 g, 5.0 mmol) at 0°C. The reaction solution was then heated to 25°C and stirred for 12 hours. After the reaction was completed, the mixture was quenched with water, extracted multiple times with dichloromethane, and the organic phases were combined, dried over anhydrous sodium sulfate, and concentrated to obtain the crude product. The crude product was then purified by silica gel column chromatography (dichloromethane:methanol = 30:1~10:1, v / v) to obtain an orange solid, compound 3 (1.04 g, 91%).

[0056] Step (4): Dissolve 1.00 g (10.0 mmol) of 3-hydroxy-3-methyl-2-butanone, 1.33 g (20.1 mmol) of malononitrile, and 0.10 g (1.5 mmol) of sodium ethoxide in 6.0 mL of ethanol. Stir the mixture in an ice bath for 2 hours, then heat to 80°C for 1.5 hours. After the reaction solution cools to room temperature, filter and collect the precipitate to obtain a grayish-white solid, TCF (0.79 g, 40%).

[0057] Step (5): Compound 3 (0.57 g, 2.5 mmol) and TCF (0.98 g, 5.0 mmol) were dissolved in ethanol (50.0 mL), and the mixture was stirred at 80°C for 12 hours under a nitrogen atmosphere. After the reaction was completed, the mixture was cooled to room temperature and filtered to obtain the crude product. The crude product was then purified by silica gel column chromatography (dichloromethane:methanol = 25:1~10:1, v / v) to give a dark green solid, namely compound TEC-OH (0.81 g, 80%).

[0058] Step (6): Under a nitrogen atmosphere at 0°C, a solution of 2,4-dinitrofluorobenzene (0.23 g, 1.2 mmol) in dichloromethane (5.0 mL) was slowly added dropwise to a solution of TEC-OH (0.41 g, 1.0 mmol) and triethylamine (0.30 g, 3.0 mmol) in dichloromethane (30.0 mL). The reaction solution was then heated to 25°C and stirred for 12 hours. After the reaction was completed, the solvent was removed by concentration to obtain the crude product. The crude product was finally purified by silica gel column chromatography (dichloromethane:methanol = 100:0~100:1, v / v) to obtain a dark green solid product, TEC-H2S (0.50 g, 87%).

[0059] Example 3: Preparation of a colorimetric-fluorescence dual-channel near-infrared probe for H2S specific detection.

[0060] Step (1): At 0°C, phosphorus tribromide (3.6 mL, 38.1 mmol) was slowly added dropwise to a solution of N,N-dimethylformamide (4.0 mL, 52.0 mmol) and dichloromethane (20.0 mL). The solution was then heated to 40°C and stirred for 30 minutes to form a white suspension. Cyclohexanone (1.9 mL, 18.4 mmol) was added dropwise, and the mixture was stirred at 40°C for 8 hours. After the reaction was complete, the mixture was poured into ice water, and the pH was adjusted to neutral with sodium bicarbonate. The mixture was then extracted multiple times with dichloromethane, the organic phases were combined, dried over anhydrous sodium sulfate, and concentrated to obtain a yellow oil.

[0061] Step (2): Compound 1 (4.54 g, 24.0 mmol), cesium carbonate (6.00 g, 18.4 mmol), and 2-hydroxy-4-methoxybenzaldehyde (1.5 g, 9.9 mmol) were added sequentially to a round-bottom flask. Ethanol (15.0 mL) was added to dissolve the mixture, and the mixture was stirred at 40°C for 8 hours. After the reaction was complete, the mixture was quenched with water, extracted multiple times with dichloromethane, and the organic phases were combined, dried over anhydrous sodium sulfate, and concentrated to obtain the crude product. The crude product was recrystallized from ethyl acetate to give a yellow solid, compound 2 (1.89 g, 79%).

[0062] Step (3): Boron tribromide (9.00 g, 36.0 mmol) was slowly added dropwise to a solution of dichloromethane (10.0 mL) containing compound 2 (1.50 g, 6.3 mmol) at 0°C. The reaction solution was then heated to 40°C and stirred for 8 hours. After the reaction was completed, the mixture was quenched with water, extracted multiple times with dichloromethane, and the organic phases were combined, dried over anhydrous sodium sulfate, and concentrated to obtain the crude product. The crude product was then purified by silica gel column chromatography (dichloromethane:methanol = 30:1~10:1, v / v) to obtain an orange solid, compound 3 (1.35 g, 94%).

[0063] Step (4): Dissolve 1.50 g (15.0 mmol) of 3-hydroxy-3-methyl-2-butanone, 1.50 g (22.8 mmol) of malononitrile, and 0.30 g (4.5 mmol) of sodium ethoxide in 6.0 mL of N,N-dimethylformamide. Stir the mixture in an ice bath for 2 hours, then heat to 100°C for 0.5 hours. After the reaction solution cools to room temperature, filter and collect the precipitate to obtain a grayish-white solid, TCF (1.85 g, 62%).

[0064] Step (5): Compound 3 (0.57 g, 2.5 mmol) and TCF (1.47 g, 7.5 mmol) were dissolved in N,N-dimethylformamide (50.0 mL), and the mixture was stirred at 100°C for 8 hours under an argon atmosphere. After the reaction was completed, the mixture was cooled to room temperature and filtered to obtain the crude product. The crude product was then purified by silica gel column chromatography (dichloromethane:methanol = 25:1~10:1, v / v) to obtain a dark green solid, namely compound TEC-OH (0.91 g, 89%).

[0065] Step (6): Under an argon atmosphere, a solution of 2,4-dinitrofluorobenzene (1.00 g, 5.4 mmol) in dichloromethane (6.0 mL) was slowly added dropwise to a solution of TEC-OH (1.00 g, 2.4 mmol) and triethylamine (1.00 g, 10.0 mmol) in dichloromethane (30.0 mL). The reaction solution was then heated to 40°C and stirred for 8 hours. After the reaction was completed, the solvent was removed by concentration to obtain the crude product. The crude product was finally purified by silica gel column chromatography (dichloromethane:methanol = 100:0~100:1, v / v) to obtain a dark green solid product, TEC-H2S (1.28 g, 93%).

[0066] Characterization data of probe TEC-H2S:

[0067] 1 HNMR ( Figure 1 )(500 MHz, DMSO) δ 8.92 (d, J = 2.8 Hz, 1H), 8.61 (d, J =15.6 Hz, 1H), 8.47 (dd, J = 9.3, 2.8 Hz, 1H), 7.60 (d, J = 8.5 Hz, 1H), 7.34(d, J = 9.3 Hz, 1H), 7.27 (s, 1H), 7.19 (s, 1H), 7.12 (dd, J = 8.4, 2.4 Hz,1H), 6.37 (d, J = 15.4 Hz, 1H), 2.68 (s, 2H), 2.56 (t, J = 5.8 Hz, 2H), 1.78(t, J = 5.7 Hz, 2H), 1.68 (s, 6H).

[0068] HRMS ( Figure 2 ): calculated for [M+Na + : 598.1333, m / z found: 598.1334.

[0069] Application Example 1: Absorption and fluorescence spectra of the probe (using the probe synthesized in Example 2) before and after reaction with H2S.

[0070] A probe solution and an aqueous H₂S solution were prepared, and then the probe solution and the aqueous H₂S solution were mixed and reacted for 40 minutes before the absorption and fluorescence spectra were measured. The concentration of the probe in the reaction system was 10 μM, and the concentration of H₂S was 400 μM. All tests were performed in a dimethyl sulfoxide:phosphate buffer (PBS, pH 7.4) aqueous solution (6:4 V / V) system at 25 °C. The absorption spectra are shown below. Figure 3 As shown in (a), the fluorescence spectrum is as follows: Figure 3 As shown in (b), it can be seen from the figure that before reacting with H2S, the probe emits almost no fluorescence and the solution is blue; after the reaction, its fluorescence intensity is significantly enhanced and the solution turns cyan-green, indicating that the probe has the ability to be used for colorimetric visualization detection of H2S.

[0071] Application Example 2: Fluorescence spectra and linear relationships of the probe (using the probe synthesized in Example 2) after reacting with different concentrations of H2S.

[0072] A probe solution and H₂S aqueous solutions of different concentrations were prepared. The probe solution and H₂S aqueous solutions were then mixed and reacted for 40 minutes before fluorescence spectra were measured. The probe concentration in the reaction system was 10 μM, and the H₂S concentration ranged from 0 to 400 μM. The fluorescence spectra are shown below. Figure 4 As shown in (a), the linear relationship is as follows: Figure 4 As shown in (b), the fluorescence intensity of the probe gradually increases with increasing H2S concentration. Within the H2S concentration range of 5–100 μM, the fluorescence intensity exhibits a good linear relationship with the concentration, and the calculated detection limit is 81.79 nM, indicating that this probe can be used for the quantitative detection of trace H2S.

[0073] Application Example 3: Fluorescence and color changes after the probe (using the probe synthesized in Example 2) reacts with H2S and different analytes.

[0074] A probe solution, along with aqueous solutions of H2S and various analytes, were prepared. The probe solution was then mixed with the H2S and analyte aqueous solutions and reacted for 40 minutes before fluorescence spectra were measured. The concentration of the probe in the reaction system was 10 μM, and the concentrations of H2S and various analytes were 400 μM.

[0075] The analytes include: metal ions (K) + Na + NH4 + Ba 2+ Zn 2+ Ca 2+ Mg 2+ Fe 2+ Fe 3+ , ), inorganic anions (.Cl - , Br - , I - NO2 - NO3 - , ClO - HPO4 - SCN - SO3 2- HSO4 - HCO3 - CO3 2- SO4 2- S2O3 2- C2O4 2- ,) and small organic molecules (Cys, Ala).

[0076] like Figure 5 As shown in (a), the probe exhibits a significant fluorescence response only to H2S; Figure 5 (b) shows that common ions do not significantly interfere with the fluorescence response of the probe to H2S, indicating that the probe has excellent selectivity and anti-interference ability for H2S.

[0077] Application Example 4: Application of the probe (using the probe synthesized in Example 2) in the detection of water samples from different real environments.

[0078] Probe solutions and H2S solutions of different concentrations were prepared by filtering lake water, mineral water, and tap water using microporous membranes. Then, a spiked recovery method was used to add different concentrations of H2S to the probe solution, and the recovery rate and relative standard deviation were tested. The probe concentration in the reaction system was 10 μM, and the H2S concentrations were 20.00, 40.00, and 60.00 μM.

[0079] Table 1. Detection of H2S recovery rate in three environmental water samples using the probe TEC-H2S

[0080]

[0081] As shown in Table 1, the H2S recovery rates of the three different water samples ranged from 97.40% to 110.80%, and the relative standard deviations (RSD) were all less than 3.00%, indicating that the probe can be used for accurate quantitative analysis of H2S in environmental water samples.

[0082] Application Example 5: Color change response of probe (using the probe synthesized in Example 2) test paper to different concentrations of water and gas H2S.

[0083] A simple probe test strip can be prepared by immersing filter paper in a 200 μM probe dimethyl sulfoxide solution for 1 minute, then removing it and blowing it with a hair dryer for a period of time.

[0084] Prepare water and gaseous H2S samples of different concentrations, add water phase H2S of different concentrations to probe test paper and observe the color change; at the same time, pass H2S gas of different concentrations into a closed device containing probe test paper and observe the color change of the test paper.

[0085] like Figure 6 As shown in (a), as the concentration of H2S solution added increases, the color of the probe paper gradually changes from blue to yellow, and the color depth gradually increases; Figure 6 (b) shows that as the concentration of H2S in the gas increases, the test strip not only turns significantly yellow, but its response time also shortens with increasing concentration. These results indicate that the probe test strip can be used for convenient, low-cost, and visual detection of H2S in water and gas.

[0086] The above embodiments are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, combinations, or simplifications made within the spirit and principle of the present invention should be considered as equivalent embodiments of the present invention and included within the scope of the claims of the present invention.

Claims

1. A method for preparing a colorimetric-fluorescent dual-channel near-infrared probe for H2S-specific detection, characterized in that, Comprise the following steps: Step (1): with anhydrous N, N-dimethylformamide DMF, dichloromethane CH2Cl2, phosphorus tribromide PBr3, cyclohexanone as the reaction raw material, compound 1 is prepared; Step (2): compound 1, cesium carbonate Cs2CO2 and 2-hydroxy-4-methoxybenzaldehyde are added to organic solvent A, and the reaction is carried out under stirring, and compound 2 is obtained after treatment; Step (3): at 0 °C, boron tribromide BBr2 is slowly added dropwise into a dichloromethane solution containing compound 2; the reaction is carried out under stirring, and compound 3 is obtained after treatment; Step (4): at 0 °C, 3-hydroxy-3-methyl-2-butanone, malononitrile and sodium ethoxide are dissolved in organic solvent B to obtain a mild solution, and then heated reaction is carried out, and TCF is obtained after treatment; Step (5): compound 3 and TCF are dissolved in organic solvent C and reacted under inert gas protection, after the reaction is completed, treatment is carried out to obtain TEC-OH; Step (6): at 0 °C and under inert gas protection, a dichloromethane solution A containing TEC-OH and triethylamine is slowly added dropwise with a dichloromethane solution B containing 2, 4-dinitrofluorobenzene; then the reaction solution is warmed to carry out the reaction, and the probe TEC-H2S is obtained after treatment.

2. The preparation method of a colorimetric-fluorescent dual-channel near-infrared probe for H2S specific detection according to claim 1, characterized in that, Said step (1) is specifically: At 0 °C, phosphorus tribromide PBr3 is slowly added dropwise into a mixed solution of anhydrous N, N-dimethylformamide DMF and dichloromethane CH2Cl2; after the solution is warmed to 10~40 °C, cyclohexanone is added dropwise, and the reaction is carried out under stirring for 8~16 hours, and compound 1 is obtained after treatment.

3. The method according to claim 2, wherein, In said step (1): In the mixed solution, the volume ratio of anhydrous N, N-dimethylformamide and dichloromethane is 1:2~1:5; 0.5~1.5 milliliters of phosphorus tribromide PBr3 and 0.2~0.8 milliliters of cyclohexanone are added for every 10.0 milliliters of the mixed solution; The treatment is as follows: the mixture after the reaction is completed is poured into ice water, sodium bicarbonate is used to adjust the pH to neutral, dichloromethane is used for multiple extractions, the organic phase is collected and concentrated, and yellow oil, i.e. compound 1, is obtained.

4. The method according to claim 1, wherein, In said step (2): The organic solvent A includes N, N-dimethylformamide DMF, dichloromethane CH2Cl2 and ethanol CH3CH2OH; 2.0~6.0 grams of compound 1, 2.00~6.00 grams of cesium carbonate Cs2CO3 and 0.50~1.50 grams of 2-hydroxy-4-methoxybenzaldehyde are added for every 15.0 milliliters of the organic solvent A; The reaction temperature is 10~40 °C, and the time is 8~16 hours The treatment is as follows: after the reaction is completed, water is added for quenching, dichloromethane is used for multiple extractions, the organic phase is collected and concentrated, the crude product is obtained, ethyl acetate is used for recrystallization, and yellow solid, i.e. compound 2, is obtained.

5. The method according to claim 1, wherein, In said step (3): 2.00~9.00 grams of boron tribromide BBr3 and 0.50~1.50 grams of compound 2 are added for every 10.0 milliliters of the dichloromethane solution; The reaction temperature is 10~40 °C, and the time is 8~16 hours; The post-treatment is: after the reaction is completed, quenching with water, extracting with dichloromethane for multiple times, collecting and concentrating the organic phase to obtain a crude product; the obtained crude product is purified by silica gel column chromatography with dichloromethane and methanol mixed solvent as a washing agent to obtain an orange solid, i.e. compound 3.

6. The method according to claim 1, wherein, In the step (4), the organic solvent B includes ethanol, N,N-dimethylformamide; 0.50-1.50 g of 3-hydroxy-3-methyl-2-butanone and 0.50-1.50 g of malononitrile are added in 6.0 ml of the organic solvent B, and 0.05-0.30 g of sodium ethoxide is added; The heating reaction temperature is 60-100°C, and the time is 0.5-2.5 hours; The post-treatment is: after the reaction is completed, quenching with water, extracting with dichloromethane for multiple times, collecting and concentrating the organic phase to obtain a crude product; the obtained crude product is purified by silica gel column chromatography with dichloromethane and methanol mixed solvent as a washing agent to obtain an orange solid, i.e. compound 3. In the step (5), the molar ratio of the compound 3 to TCF is 1:1-1:3; 7. The method according to claim 1, wherein, The organic solvent C includes ethanol, N,N-dimethylformamide, and the inert gas includes nitrogen and argon; The reaction temperature is 60-100°C, and the time is 8-16 hours; The post-treatment is: after the reaction is completed, quenching with water, extracting with dichloromethane for multiple times, collecting and concentrating the organic phase to obtain a crude product; the obtained crude product is purified by silica gel column chromatography with dichloromethane and methanol mixed solvent as a washing agent to obtain an orange solid, i.e. compound 3. In the step (6), the volume ratio of the dichloromethane solution A to the dichloromethane solution B is 5:1-10:1; 0.10-1.00 g of TEC-OH and 0.10-1.00 g of triethylamine are added in 30.0 ml of the dichloromethane solution A, and 0.10-0.50 g of 2,4-dinitrofluorobenzene is added in 3.0 ml of the dichloromethane solution B; The reaction temperature is 10-40°C, and the time is 8-16 hours; 8. The method according to claim 1, wherein, The inert gas includes nitrogen and argon; The post-treatment is: after the reaction is completed, quenching with water, extracting with dichloromethane for multiple times, collecting and concentrating the organic phase to obtain a crude product; the obtained crude product is purified by silica gel column chromatography with dichloromethane and methanol mixed solvent as a washing agent to obtain an orange solid, i.e. compound 3. The colorimetric-fluorescent dual-channel near-infrared probe is prepared by the preparation method in any one of claims 1-8, and has the following structure: The colorimetric-fluorescent dual-channel near-infrared probe is applied to specific H2S specific detection, in particular: The colorimetric-fluorescent dual-channel near-infrared probe is applied to detection of water H2S; 9. A colorimetric-fluorescent dual-channel near-infrared probe for H2S specific detection, characterized in that, The colorimetric-fluorescent dual-channel near-infrared probe is loaded on a test paper and applied to water and gas H2S. 。 10. The colorimetric-fluorescent dual-channel near-infrared probe for H2S specific detection according to claim 9, characterized in that, ​ ​ ​

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