Application of phenoxazine thiazolothiazole as fluorescent probe for sensing and detecting sarin and simulant thereof

Abstract

The invention discloses an application of phenoxazine thiazolothiazole as a fluorescent probe for sensing and detecting sarin and a simulant thereof, the fluorescent probe takes a thiazolothiazole group as an electron withdrawing group and a phenoxazine group as an electron donating group, the electron donating-withdrawing effect is obvious, the Stokes shift is large, the fluorescence quantum yield is high, and the phenoxazine thiazolothiazole fluorescent probe can be used for detecting sarin and simulants thereof. The compound shows good ICT characteristics and excellent photophysical properties, and shows excellent sensing properties of high sensitivity, fast response speed, short recovery time and the like to sarin poison gas simulant DCP. According to the invention, phenoxazine thiazolothiazole is prepared into a fluorescent sensing film with good photochemical stability through a dispensing method, the film is converted into a device, a film-based fluorescent sensor is further prepared, high-sensitivity detection of sarin poison gas is expected to be realized, and the phenoxazine thiazolothiazole fluorescent sensor has great potential and application value in practical application.

Description

Technical Field

[0001] The invention belongs to the technical field of nerve agent detection, and particularly relates to the application of phenoxazine thiazolylthiazole as a fluorescent probe in sensing and detecting sarin and its analog diethyl chlorophosphate (DCP). Background Art

[0002] Chemical warfare agents are a class of toxic chemicals used specifically in military operations. These substances are often highly toxic, irritating and destructive, among which nerve agents are particularly deadly. They usually enter the human body through the respiratory tract or skin mucosa, and pose a huge threat to the lives of humans and animals by inhibiting the function of acetylcholinesterase (AChE). Considering the difficulty of handling such analytes, scientists around the world have been focusing on developing probes for nerve agent simulants (diethyl chlorophosphate, diethyl cyanophosphate), which have similar chemical structures to nerve agents but are less toxic. However, most of these probes have some common problems, such as low sensitivity in aqueous media, long response time, poor selectivity, low sensitivity, etc., which greatly limit their application in actual sample analysis.

[0003] In order to deal with this threat, scientists have actively developed a variety of methods for detecting nerve agents, including mass spectrometry, enzyme biosensors, electrochemical sensors, and photochemical sensors. Among the many technologies, fluorescent sensors are favored because of their simple operation, high sensitivity, low cost, rapid real-time response, and easy integration into equipment. In particular, thin-film-based fluorescent sensors are considered to have great application potential in the field of gas phase detection of nerve agents due to their good compatibility with equipment and their ability to more comprehensively contact the gas to be tested. Thin-film-based fluorescence sensing technology involves complex surface and interface interactions, mainly including two core processes: "energy transfer" and "mass transfer." "Therefore, the performance of the sensing film depends to a certain extent on the structural design of the sensing molecules and the structure of the active layer of the sensing film, which affects the occurrence of the sensing mechanism and the adsorption, diffusion, and analysis behavior of the analyte molecules. In order to achieve highly sensitive detection of trace harmful substances, it is particularly important to design a thin-film-based fluorescent sensor with excellent sensing units and porous structures. Summary of the invention

[0004] The present invention aims to provide an application of phenoxazine thiazolylthiazole (POZ-TTZ) as a fluorescent probe for sensing and detecting sarin and its simulants.

[0005] The structural formula of the POZ-TTZ is shown below:

[0006]

[0007] The method for using POZ-TTZ as a fluorescent probe to detect sarin and its simulants is as follows: POZ-TTZ is added to an organic solvent to prepare 1×10 -4 ~1×10 -3 mol / L POZ-TTZ solution; then the POZ-TTZ solution was drop-coated on a glass plate, and after drying, a POZ-TTZ fluorescent sensing film was obtained, which was used to sense and detect sarin and its simulants.

[0008] Furthermore, it is preferred that the organic solvent is toluene or dichloromethane.

[0009] Furthermore, the POZ-TTZ fluorescent sensing film can also be prepared into a film-based fluorescent sensor for sensing and detecting sarin and its simulants.

[0010] The beneficial effects of the present invention are as follows:

[0011] The POZ-TTZ used in the present invention uses the thiazolyl thiazole group as an electron acceptor and the phenoxazine group as an electron-pushing donor to adjust the push-pull electron effect in the molecule. The push-pull electron effect is obvious, the Stokes shift is large, and the fluorescence quantum yield is high. Different fluorescence colors are shown in solvents of different polarities. The fluorescence emission spectrum has a strong red shift, showing good ICT (intramolecular charge transfer) characteristics and excellent photophysical properties. It shows high sensitivity, fast response speed, short recovery time and other excellent sensing performances for the sarin gas simulant DCP. The present invention prepares POZ-TTZ azole into a fluorescent sensing film with good photochemical stability by a drop coating method, and the film is deviceized to further prepare a film-based fluorescent sensor. The sensor shows excellent performances such as high sensitivity (detection limit as low as 1 ppb), fast response speed (less than 2s), and short recovery time (60s) for DCP vapor. It shows a highly sensitive and reversible sensing effect for DCP, and is expected to achieve high-sensitivity detection of sarin gas, and has great potential and application value in practical applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 is the UV-visible absorption spectra of POZ-TTz with different concentrations in DCM.

[0013] Figure 2 is the fluorescence emission spectra of POZ-TTz with different concentrations in DCM.

[0014] Figure 3 is the UV-visible absorption spectra of POZ-TTz in different solvents (concentration 1×10 -5 mol / L).

[0015] Figure 4is the fluorescence emission spectra of POZ-TTz in different solvents (concentration 1×10 -5 mol / L; excitation wavelength is 346nm).

[0016] Figure 5 It is the fluorescence emission spectrum of POZ-TTz fluorescence sensing film before and after the action of DCP.

[0017] Figure 6 This is the stability test result of POZ-TTz fluorescent sensing film (excitation wavelength is 430nm).

[0018] Figure 7 These are the sensitivity test results of POZ-TTz fluorescent sensing film to DCP vapor of different concentrations.

[0019] Figure 8 This is the sensing kinetic result of POZ-TTz fluorescent sensing film to DCP vapor.

[0020] Fig. 9 This is the reversibility test result of POZ-TTz fluorescent sensing film to DCP vapor.

[0021] Fig.10 This is the selectivity test result of POZ-TTz fluorescent sensing film to DCP vapor. DETAILED DESCRIPTION

[0022] The technical scheme of the present invention is further illustrated by specific embodiments below. Those skilled in the art should understand that the specific embodiments are only used to illustrate the present invention, but not to limit the present invention. Those of ordinary skill in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, all equivalent technical solutions also belong to the scope of the present invention, and the patent protection scope of the present invention should be defined by the claims.

[0023] Example 1

[0024] 1. Preparation of POZ-TTz

[0025]

[0026] Step 1: Under anhydrous and oxygen-free conditions, a mixture of dithioacetamide (0.60 g, 5 mmol) and 4-bromobenzaldehyde (2.00 g, 11 mmol) was added to a 50 mL double-mouthed round-bottom flask, 30 mL of DMF was added, and the mixture was refluxed at 150 ° C for 8 h. After the reaction was completed, the reaction solution was cooled to room temperature, extracted with dichloromethane and washed with water, and water was removed with anhydrous sodium sulfate. The organic solvent was removed by rotary evaporation, and column chromatography was separated and purified (the developing solvent was a mixture of petroleum ether and dichloromethane in a volume ratio of 1:1), and finally recrystallized with cyclohexanone. After vacuum drying, 1.20 g of yellow compound 1 was obtained with a yield of 53%. The structural characterization results of compound 1 are as follows: 1 H NMR (600 MHz, CDCl 3 ): δ(ppm)7.88(d,4H),7.63(d,4H); APCI-HRMS:[(M+H)] + (C 16 H 8 Br 2 N 2 S 2 ):Theoretical value 452.8548, measured value 452.8547.

[0027] Step 2: Under anhydrous and oxygen-free conditions, compound 1 (0.90 g, 2 mmol), phenoxazine (0.85 g, 5 mmol), tri-tert-butylphosphine tetrafluoroborate (0.09 g, 0.30 mmol), palladium acetate (0.023 g, 0.10 mmol) and sodium tert-butoxide (0.45 g, 4.69 mmol) were added to a 50 mL Shrek bottle, completely dissolved in freshly distilled toluene (30 mL), and the reaction solution was stirred at 110 ° C for 48 h. After the reaction was completed, the reaction solution was cooled to room temperature, quenched with saturated brine, extracted with chloroform, and the solvent was removed by rotary evaporation. Column chromatography was separated and purified (the developing solvent was a mixture of petroleum ether: dichloromethane in a volume ratio of 1:1), and finally recrystallized with dichloromethane / n-hexane. After vacuum drying, 0.97 g of the orange target compound POZ-TTz was obtained with a yield of 71%. The structural characterization results of POZ-TTz are as follows: 1 H NMR (600 MHz, CDCl 3 ): δ(ppm)7.44(d,4H),7.26(d,4H),7.04(d,4H),6.99(d,4H),6.96(t,8H); APCI-HRMS:[(M+H)] + (C 40 H 24 N 4 O 2 S 2):Theoretical value 657.1424, measured value 657.1413.

[0028] POZ-TTz was dissolved in DCM to a concentration of 2.5×10 -6 mol / L~1.0×10 -4 mol / L POZ-TTz solution, and measured its UV-visible absorption and fluorescence emission spectra. The results are shown in Figure 1 and Figure 2 .Depend on Figure 1 The UV-visible absorption spectrum shows that the maximum absorption peak wavelength of POZ-TTz is located at 340nm. With the increase of POZ-TTz concentration, the maximum absorption peak intensity gradually increases. At the same time, the shape and position of its characteristic absorption peak do not change significantly, indicating that within this concentration range, POZ-TTz does not associate or dissociate in DCM. Figure 2 The fluorescence emission spectrum shows that the maximum emission wavelengths of POZ-TTz are at 410nm and 630nm, respectively. Within the measured concentration range, the maximum emission peak intensity of POZ-TTz is proportional to the concentration, and the peak shape and peak position do not change significantly, indicating that POZ-TTz does not have aggregation-induced quenching effect.

[0029] POZ-TTz was dissolved in different solvents to prepare a concentration of 1.0×10 -5 mol / L POZ-TTz solution to explore the solvent dependence effect of POZ-TTz. Figure 3 The UV-visible absorption spectrum shows that the UV-visible absorption peak wavelength does not change when the solvent polarity is changed, indicating that the polarity of the solvent has almost no effect on the electronic structure of the ground state of POZ-TTz. Figure 4 The fluorescence emission spectrum shows that with the increase of solvent polarity, the maximum emission peak of POZ-TTz has an obvious red shift, indicating that POZ-TTz has strong intramolecular charge transfer characteristics.

[0030] 2. POZ-TTz sensor detection DCP

[0031] POZ-TTz was added to toluene to prepare 1×10 -4 mol / L POZ-TTz toluene solution; 30 μL 1×10 - 4 mol / L POZ-TTz toluene solution was drop-coated on a glass plate and dried to obtain the POZ-TTz fluorescent sensing film.

[0032] The POZ-TTz fluorescent sensor film was used to preliminarily test DCP vapor. DCP vapor was applied to the POZ-TTz fluorescent sensor film to test its fluorescence emission spectrum. It was observed that the film fluorescence was significantly quenched after the addition of DCP (see Figure 5 ).

[0033] The stability of the POZ-TTz fluorescent sensor film was investigated on the sensing platform. The fluorescence intensity of the POZ-TTz fluorescent sensor film was quenched by only 1.5% using a 430 nm lamp for 8 h. Figure 6 ).

[0034] The sensitivity test of POZ-TTz fluorescent sensing film shows that POZ-TTz fluorescent sensing film can detect DCP vapor at ppt level (see Figure 7 ), indicating that the sensing film is expected to be applied to the detection of ultra-low concentration DCP.

[0035] In addition, the response kinetics of the POZ-TTz fluorescent sensing film to DCP vapor was analyzed in detail (see Figure 8 ), the sensing process is indexed and quantified, and the sensing performance of the POZ-TTz fluorescent sensor film is evaluated at a deeper level. The response time of the POZ-TTz fluorescent sensor film to DCP vapor is less than 2s. When the injection is stopped, the signal begins to decrease, and the recovery time of the sensor film (defined as the duration for the output to recover from the maximum intensity to 90% of the initial intensity) is 73s. The excellent reversibility, fast response time and short recovery period shown by the sensor film prove that the POZ-TTz fluorescent sensor film of the present invention has the value of manufacturing a film-based fluorescent sensor that can be practically applied.

[0036] Further reversible sensing tests of POZ-TTz fluorescent sensing film to DCP were carried out, such as Fig. 9 As shown, at lower DCP vapor concentrations, the POZ-TTz fluorescent sensing film showed nearly complete reversibility in the fluorescent response to DCP vapor in at least 20 cycles, with only a slight decrease in the film performance and fluorescence response intensity. This sensing test showed that the POZ-TTz fluorescent sensing film has good reusability and can achieve continuous real-time monitoring of DCP vapor.

[0037] The selective detection results of POZ-TTz fluorescent sensing film for DCP are shown in Fig.10 .Depend on Fig.10 It can be seen that compared with some common VOCs gases (hydrochloric acid, trichloromethane (TCM), acetone, dichloromethane, n-hexane, benzene, methanol, and toluene), the response intensity of DCP vapor is the largest, indicating that the obtained POZ-TTz fluorescent sensing film has good selectivity for the detection of DCP vapor.

[0038] The performance of POZ-TTz fluorescent sensing film in sensing DCP was compared with the fluorescent materials TCzP-CMP (Nat. Commun., 2022, 13, 5189.), P1 (ACS Appl. Mater. Interfaces, 2020, 12, 11055-11062.), QN (J. Mol. Liq., 2021, 327, 114799.), NDTAZ (ACS Sens., 2022, 7, 1946-1957.) and color visualization paper PDAC (Anal. Chem., 2019, 91, 12070-12076.), TPPyP (Sens. Actuators B Chem., 2025, 425, 136983.), TAZ-P1 (Sens. Actuators B Chem., 2025, 425, 136983.). Chem., 2020, 322, 128611.) for performance comparison, and the results are shown in Table 1.

[0039] Table 1 Performance comparison of POZ-TTz fluorescent sensing film and reported DCP vapor sensing materials

[0040]

[0041] In summary, the POZ-TTz fluorescent sensing film of the present invention has good performance in terms of stability, selectivity and reusability in the detection of DCP vapor, and the detection limit can be as low as 1 ppb, which is much lower than the detection limit reported in previous studies.

Claims

1. Application of phenoxazine thiazolyl thiazole as a fluorescent probe for sensing and detecting sarin and its analogs, wherein the structural formula of the phenoxazine thiazolyl thiazole is as follows:

2. The use of the phenoxazine thiazolylthiazole according to claim 1 as a fluorescent probe for sensing sarin and its simulants, characterized in that: Phenoxazine thiazole and thiazole were added to the organic solvent to prepare 1×10 -4 ~1×10 -3 mol / L phenoxazine thiazolyl thiazole solution; then the phenoxazine thiazolyl thiazole solution is drop-coated on a glass plate, and after drying, a phenoxazine thiazolyl thiazole fluorescent sensing film is obtained, which is used for sensing and detecting sarin and its simulants.

3. The use of the phenoxazine thiazolylthiazole as a fluorescent probe for sensing sarin and its simulants according to claim 2, characterized in that: The organic solvent is toluene or dichloromethane.

4. The use of the phenoxazine thiazolylthiazole as a fluorescent probe for sensing sarin and its simulants according to claim 2, characterized in that: The phenoxazine thiazolylthiazole fluorescence sensing film is prepared into a film-based fluorescence sensor for sensing and detecting sarin and its simulants.

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