An imine molecular sensor with five detection functions, a two-component gel, and its preparation method and application

Abstract

The present invention relates to the technical field of organic material detection, and in particular to an imine molecular sensor with five detection functions, a two-component gel, and a preparation method and application thereof. 3+ 、Co 2+ 、Ni 2+ It has three signal responses: fluorescence on-off, ultraviolet absorption, and color change, and has dual detection performance of ultraviolet absorption and fluorescence on-off for acid and alkali changes; the imine molecular sensor and cholesterol half ester can form a two-component gel through heating-low temperature ultrasonic cooling method; Fe 3+ 、Co 2+ 、Ni 2+ After the addition of NaOH and HCl, the orange-yellow color of the gel changes to milky white, reddish brown, transparent red, milky white, and milky white under sunlight, and the orange-red fluorescence of the gel disappears under ultraviolet light, realizing the dual state of the imine molecule solution and gel for Fe 3+ 、Co 2+ 、Ni 2+ The imine molecular sensor provided by the present invention has the advantages of mild synthesis conditions and simple preparation, which creates favorable conditions for its promotion and application.

Description

Technical Field

[0001] The present invention relates to the technical field of organic material detection, in particular to a method for detecting Fe in both solution and gel state. 3+ 、Co 2 + 、Ni 2+ Imine molecular sensors and their applications with fast and sensitive detection capabilities in acidic and alkaline environments. Background Art

[0002] With the rapid development of industrial production, metal ion pollution in the environment is becoming increasingly serious, especially the ecological risks posed by heavy metal ions such as iron, cobalt, and nickel. These metal pollutants are not only highly toxic, but also bioaccumulative and environmentally persistent. Once discharged into the natural environment in excess of permitted levels, they pose serious risks to soil, ecosystems, and human health. Related studies have shown that metal ions in industrial wastewater can penetrate into groundwater systems through surface runoff, and heavy metal ions carried in atmospheric particulate matter can accumulate in soil through dry and wet deposition. This cumulative effect not only inhibits crop growth but also disrupts the structure of soil microbial communities. Epidemiological surveys have shown that excessive levels of heavy metals in the human body can cause a variety of malignant diseases, including malignant tumors, liver and kidney dysfunction, and neurological diseases. Therefore, the precise detection and identification of metal ions has become a core research area in environmental science. It not only facilitates the control of environmental pollution but also serves as a key guarantee for green and sustainable development. Furthermore, with the continuous development of society, the discharge of various waste acids and alkalis from industrial production processes is increasing. When these untreated acids or bases are released directly into the soil, they can cause changes in the acidity or alkalinity of the surrounding environment, causing plant wilt and animal death, bringing significant harm to human production and life. Therefore, the chemical production industry requires sensitive analytical testing technologies to constantly monitor acid and alkali discharges that can pollute the water and soil resources that people rely on for survival. At the same time, industrial and agricultural production processes that require specific acidic or alkaline environments to function properly also require efficient pH testing technologies to track and improve product quality and work efficiency.

[0003] Currently, ion detection is typically performed using high-performance liquid chromatography (HPLC) and inductively coupled plasma mass spectrometry (ICP-MS). While these methods can accurately monitor the concentrations of target ions in various systems, they often suffer from limitations such as expensive instrumentation, lengthy testing times, high costs, and difficulty in on-site testing. Fluorescent molecular sensing technology has garnered increasing attention due to its high sensitivity, low cost, and ease of use. Fluorescent molecular sensors convert molecular-level recognition into easily detectable optical signals, such as ultraviolet and fluorescence, enabling real-time, rapid, and sensitive in-situ detection. They have been widely applied in fields such as industrial and agricultural production and environmental monitoring. Numerous molecular sensors with diverse functionalities have been developed to meet diverse test targets. However, most current fluorescent molecular sensors offer sensitive detection capabilities for only a single specific ion and exhibit relatively limited functionality. Multifunctional fluorescent molecular sensors not only avoid the complex preparation of multiple single-molecule sensors but also overcome the technical bottleneck of single-dimensional detection. They can simultaneously detect multiple ions, shortening detection time and steps, saving resources, improving efficiency, and achieving both time and cost savings. However, due to the complex preparation and high cost of multifunctional molecular sensors, the number of currently developed sensors is limited, making it difficult to meet the growing market demand. Therefore, the development of multifunctional molecular sensors that are easy to prepare, sensitive and fast, and have a wide range of practical applications is also urgently needed in various monitoring fields.

[0004] Thiadiazole is a five-membered heterocyclic ring containing two nitrogen atoms and one sulfur atom. Its easily modifiable structure makes it a promising building block for molecular sensors. Schiff base compounds are organic compounds containing an imine group (-C=N-). The lone electron pair on the nitrogen atom in the imine group (-C=N-) can coordinate with metal ions to form stable coordination compounds, which have broad applications in analytical chemistry, catalytic materials, and optical technology. However, imine molecular sensors with multiple detection capabilities based on thiadiazole as the central unit have not yet been developed. Summary of the Invention

[0005] In view of the problems existing in the prior art, the present invention provides a solution and gel state of Fe 3+ 、Co 2+ 、Ni 2+ A molecular sensor with five detection functions in acid, alkali and acidic environments, wherein the molecular sensor is a symmetrical thiadiazole-diethylamino salicylimine molecule.

[0006] The present invention is achieved through the following technical solutions:

[0007] An imine molecular sensor with five detection functions, the sensor is a symmetrical thiadiazole-diethylamino salicylimine molecule, and its structure is:

[0008] .

[0009] The molecular sensor is easy to prepare and can react with Fe in solution. 3+ 、Co 2+ 、Ni 2+ With different fluorescence emission "on-off", UV absorption and intuitive color three-detection signals, it can realize the detection of Fe in different systems. 3+ 、Co 2+ 、Ni 2+ Fast and sensitive detection on site.

[0010] Another object of the present invention is to provide a method for preparing the thiadiazole-diethylamino salicylimine molecule, comprising the following steps: dissolving 1,3,4-thiadiazole-2,5-diamine in a DMF-EtOH mixed solvent, then sequentially adding 4-diethylamino salicylic aldehyde and concentrated sulfuric acid, heating to 79°C and continuing the reaction for 6-8 hours; cooling the reaction mixture to room temperature, filtering, washing the obtained crude product with anhydrous ethanol, and drying to obtain the thiadiazole-diethylamino salicylimine molecule.

[0011] Furthermore, the ratio of the 1,3,4-thiadiazole-2,5-diamine and 4-diethylamino salicylaldehyde is 1:2, the volume ratio of EtOH and DMF in the mixed solvent is 4:1, the amount of the mixed solvent added is limited to 25 mL of the mixed solvent for every 1 mmol of 1,3,4-thiadiazole-2,5-diamine, and the amount of concentrated sulfuric acid added is 50 μL of concentrated sulfuric acid for every 1 mmol of 1,3,4-thiadiazole-2,5-diamine.

[0012] The preparation reaction formula of the thiadiazole-diethylamino salicylimine molecule is:

[0013] .

[0014] The third object of the present invention is to provide the application of the thiadiazole-diethylamino salicylimine molecule solution state in acidic environment detection.

[0015] The specific performance is as follows: the thiadiazole-diethylamino salicylimine molecule has a maximum absorption at 496 nm. As the concentration of HCl increases, its maximum absorption blue shifts and the absorbance gradually decreases, while its absorption near 345 nm gradually increases. During this period, as the concentration of HCl increases, the maximum fluorescence emission of the imine molecule near 565 nm gradually decreases and then quenches, indicating that the thiadiazole-diethylamino salicylimine molecule has a double-peak change in ultraviolet absorption and an "on-off" dual-signal detection performance of fluorescence emission in an acidic environment.

[0016] The fourth object of the present invention is to provide the application of the thiadiazole-diethylamino salicylimine molecule solution state in alkaline environment detection.

[0017] The specific performance is as follows: with the increase of the concentration of NaOH added, the maximum absorption absorbance of the thiadiazole-diethylamino salicylimine molecule at 496 nm first decreases, then increases and red-shifts, and the maximum fluorescence emission of the molecule near 565 nm is quenched, indicating that the imine molecule has fluorescence "on-off" and dynamic ultraviolet absorption dual-signal detection performance in alkaline environment.

[0018] The fifth object of the present invention is to provide a method for forming a two-component organic gel by using the thiadiazole-diethylamino salicylimine molecule (TS) and the cholesterol half ester gelator (CS).

[0019] Furthermore, the “heating-low-temperature ultrasonic cooling” gelation method was adopted: with a TS:CS molar mass ratio of 1:35, 0.5 mg of TS and the corresponding amount of CS gel were weighed and placed in a 2 mL glass vial, 0.3 mL of tert-butanol was added, and the mixture was heated until the two-component gel factor was completely dissolved, and then ultrasonically cooled at about -5°C for 2 min to form an orange-yellow TSCS two-component gel.

[0020] The sixth object of the present invention is to provide the application of the TSCS two-component gel formed by the thiadiazole-diethylamino salicylimine molecule and the cholesterol half ester gelator for NaOH detection.

[0021] The specific performance is as follows: TSCS two-component gel is orange-yellow under sunlight and has orange-red fluorescence emission properties under ultraviolet light. After the addition of NaOH, it changes from orange-yellow gel to milky white gel under sunlight, and its orange-red fluorescence emission disappears under 365 nm ultraviolet light.

[0022] The seventh object of the present invention is to provide the application of the TSCS two-component gel formed by the thiadiazole-diethylamino salicylimine molecule and the cholesterol half ester gelator for acidic environment detection.

[0023] The specific performance is as follows: the orange-yellow color of the TSCS two-component gel changes to milky white after the addition of HCl, and the orange-red fluorescence emission disappears under 365 nm ultraviolet light.

[0024] The eighth object of the present invention is to provide a TSCS two-component gel formed by the thiadiazole-diethylamino salicylimine molecule and the cholesterol half ester gel to Fe 3+ 、Co 2+ 、Ni 2+ The detection application is as follows:

[0025] Fe 3+ After the addition, the TSCS two-component gel turned from orange to white under sunlight, and its orange-red fluorescence emission disappeared under 365 nm ultraviolet light.

[0026] Co 2+After the addition, the TSCS two-component gel changed from orange-yellow to reddish-brown under sunlight, and its orange-red fluorescence emission disappeared under 365 nm ultraviolet light.

[0027] Ni 2+ After the addition, the TSCS two-component gel changes from orange-yellow to transparent red under sunlight, and its orange-red fluorescence emission disappears under 365 nm ultraviolet light.

[0028] Compared with the prior art, the present invention has the following technical effects: the thiadiazole-diethylamino salicylimine molecule solution state has a great influence on Fe 3+ 、Co 2+ 、Ni 2+ The imine molecular sensor has three-signal detection responses: different fluorescence emission "on-off", ultraviolet absorption and intuitive color change; the imine molecular sensor has ultraviolet absorption double-peak change and fluorescence emission "on-off" dual-signal detection performance in acidic environment, and has fluorescence "on-off" and dynamic ultraviolet absorption dual-signal detection performance in different alkaline environments; through the "heating-low temperature ultrasonic cooling" gelation method, the imine molecular sensor and cholesterol half ester gelator form a two-component gel with orange-yellow fluorescence emission under sunlight and orange-red fluorescence emission under ultraviolet light; Fe 3+ After the addition, the gel turned from orange to white under sunlight, and its orange-red fluorescence emission disappeared under 365 nm ultraviolet light. 2+ After the addition, the gel changes from orange to reddish brown under sunlight, and its orange-red fluorescence emission disappears under 365 nm ultraviolet light. 2+ After the addition, the orange-yellow gel turned into transparent red under sunlight, and its orange-red fluorescence emission disappeared under 365 nm ultraviolet light; after the addition of NaOH and HCl, the orange-yellow gel turned into milky white and the orange-red fluorescence emission disappeared, realizing the dual-state imine molecular sensor solution and gel for Fe 3+ 、Co 2+ 、Ni 2+ The thiadiazole-diethylamino salicylimine molecular sensor provided by the present invention has the advantages of mild synthesis conditions and simple preparation, which creates favorable conditions for its promotion and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is the NMR image of the thiadiazole-diethylamino salicylimide molecular sensor.

[0030] Figure 2 Select the UV absorption spectrum of the thiadiazole-diethylamino salicylimide molecular sensor for metal ions.

[0031] Figure 3 Selective fluorescence emission diagram of thiadiazole-diethylamino salicylimide molecular sensor for metal ions.

[0032] Figure 4 Diagram of selective UV light irradiation of thiadiazole-diethylamino salicylimide molecular sensor for metal ions.

[0033] Figure 5 Thiadiazole-diethylamino salicylimine molecular sensor for different concentrations of Fe 3+ Fluorescence emission graph.

[0034] Figure 6 The thiadiazole-diethylamino salicylimine molecular sensor was used to detect different concentrations of Ni 2+ Fluorescence emission graph.

[0035] Figure 7 Thiadiazole-diethylamino salicylimine molecular sensor for different concentrations of Co 2+ Fluorescence emission graph.

[0036] Figure 8 This is the UV absorption diagram of the thiadiazole-diethylamino salicylimide molecular sensor in different alkaline environments.

[0037] Figure 9 The fluorescence emission diagram of the thiadiazole-diethylamino salicylimide molecular sensor in different alkaline environments.

[0038] Figure 10 This is the UV absorption diagram of the thiadiazole-diethylamino salicylimide molecular sensor in different acidic environments.

[0039] Figure 11 The fluorescence emission diagram of the thiadiazole-diethylamino salicylimide molecular sensor in different acidic environments.

[0040] Figure 12 This is a diagram of a two-component gel formed by a thiadiazole-diethylamino salicylimide molecular sensor and a sterol gelator.

[0041] Figure 13 SEM image of the two-component gel formed by the thiadiazole-diethylamino salicylimine molecular sensor and the sterol gelator.

[0042] Figure 14 Diagram of acid detection using a two-component gel formed by a thiadiazole-diethylamino salicylimine molecular sensor and a sterol gelator.

[0043] Figure 15 This is a diagram of alkali detection formed by a two-component gel of thiadiazole-diethylamino salicylimine molecular sensor and a sterol gelator.

[0044] Figure 16 The figure below shows the daylight-induced formation of a two-component gel for metal ion detection using a thiadiazole-diethylamino salicylimide molecular sensor and a sterol gelator.

[0045] Figure 17 The figure below shows the thiadiazole-diethylamino salicylimine molecular sensor and the sterol gelator forming a two-component gel for metal ion detection under ultraviolet light irradiation. DETAILED DESCRIPTION

[0046] The present invention discloses a method for treating Fe in both solution and gel state. 3+ 、Co 2+ 、Ni 2+ The thiadiazole-diethylamine-based salicylimine molecular sensor has five detection functions in acid, alkali and acid environments, and its molecular structure is:

[0047] .

[0048] It can be prepared by a one-step polymerization reaction using 1,3,4-thiadiazole-2,5-diamine and 4-diethylamino salicylaldehyde as reaction raw materials. The synthesis reaction formula is:

[0049] .

[0050] Example 1

[0051] Preparation of compound A: Dissolve 1 mmol of 1,3,4-thiadiazole-2,5-diamine in 25 mL of a 1:4 DMF-EtOH mixed solvent, add 2 mmol of 4-diethylaminosalicylaldehyde and 50 μL of concentrated sulfuric acid, and heat under reflux for 6 hours. The reaction mixture is cooled to room temperature, filtered, washed with anhydrous ethanol, and dried to obtain an orange-red compound (373 mg, 80% yield).

[0052] Example 2

[0053] Preparation of compound B: Dissolve 1 mmol of 1,3,4-thiadiazole-2,5-diamine in 25 mL of a 1:4 DMF-EtOH mixed solvent, add 2 mmol of 4-diethylaminosalicylaldehyde and 50 μL of concentrated sulfuric acid, and heat under reflux for 8 hours. The reaction solution is cooled to room temperature, filtered, washed with anhydrous ethanol, and dried to obtain an orange-red compound (382 mg, 82% yield).

[0054] Compounds A and B obtained in Examples 1 and 2 were analyzed and determined by NMR. Figure 1 To, see Figure 1 , the NMR data are as follows: 1H NMR (400 MHz, DMSO-d6) δ 11.96 (s, 2H), 8.76 (s, 2H), 7.55 (d,2H), 6.45 (d, 2H), 6.34 (s, 2H), 3.48 (m, 8H), 1.17 (s, 12H); MS: ion peak m / z 466.22, [theoretical calculated value M + is 466.38]; indicating that compound A / B is basically consistent with the theoretical value of thiadiazole-diethylamino salicylimide. Therefore, the molecular structures of compounds A and B can be confirmed as follows:

[0055] That is, the thiadiazole-diethylamino salicylimine molecule.

[0056] Example 3

[0057] UV detection performance of thiadiazole-diethylamino salicylimide molecular solution for metal ions: in 90% DMF aqueous solution, the concentration was 1×10 -5 mol / L thiadiazole-diethylamino salicylimide molecule was added with 10 times the molar equivalent of Na + 、Fe 3+ , K + 、Li + 、Hg 2+ 、Co 2+ , Pb 2+ Cr 3+ 、Al 3+ 、Cd 2+ , Ca 2+ 、Mn 2+ 、Ni 2+ 、Cu 2+ , Pb 2+ 、Zn 2+ The ultraviolet absorption spectrum test of metal ions showed that the molecule had a maximum ultraviolet absorption peak at 496 nm; the addition of Co 2+ After addition of Ni 2+ After adding Fe 3+ After the addition of 2% ion of 4% ion, the molecule showed a broad peak with no structural characteristics at around 450-350 nm. After the addition of other metal ions, the UV-visible absorption spectrum of the molecule did not change significantly. Figure 2 These results indicate that the thiadiazole-diethylamino salicylimine molecule has a strong affinity for Fe. 3+ 、Co 2+ 、Ni 2+ Has good UV detection response to Fe 3+、Co 2+ 、Ni 2+ It has multiple ultraviolet absorption signal detection capabilities.

[0058] Example 4

[0059] Fluorescence detection performance of thiadiazole-diethylamino salicylimine molecular solution for metal ions: in 90% DMF aqueous solution, the concentration was 1×10 -5 mol / L thiadiazole-diethylamino salicylimide molecule was added with 10 times the molar equivalent of Na + 、Fe 3+ , K + 、Li + 、Hg 2+ 、Co 2+ , Pb 2+ Cr 3+ 、Al 3+ 、Cd 2+ , Ca 2+ 、Mn 2+ 、Ni 2+ 、Cu 2+ , Pb 2+ 、Zn 2+ The fluorescence emission spectrum test shows that the maximum emission wavelength of thiadiazole-diethylamino salicylimine molecule is around 565 nm; Ni 2+ After addition, the maximum fluorescence emission red-shifted to 570 nm and the fluorescence emission intensity decreased by 87%; Co 2+ After addition, its maximum fluorescence emission red-shifted to 572 nm and the fluorescence emission intensity decreased by 89%; Fe 3+ After addition, its maximum fluorescence emission was quenched; after the addition of other metal ions, the fluorescence emission spectrum of the molecule did not change significantly. Figure 3 Under 365 nm ultraviolet (UV) light, the thiadiazole-diethylamino salicylimine molecular solution showed an orange-red fluorescence emission solution. 2+ 、Ni 2+ After adding, the orange-red fluorescence emission of the solution weakened, and Fe 3+ After addition, the orange-red fluorescence emission disappears, and after the addition of other metal ions, the orange-red fluorescence emission remains basically unchanged. For specific results, see Figure 4 These results indicate that the thiadiazole-diethylamino salicylimine molecule has a strong affinity for Fe 3+ 、Co 2+ 、Ni 2+ It has the potential for sensitive and intuitive fluorescence "off-on" detection.

[0060] Example 5

[0061] Effect of Thiadiazole-Diethylamino Salicylimide Molecular Solution on Fe 3+Ion fluorescence detection function: in 90% DMF aqueous solution, the concentration is 1×10 -5 mol / L thiadiazole-diethylamino salicylimine molecules and different concentrations of Fe 3+ The fluorescence emission spectrum in the presence of Fe 3+ When the concentration increased from 0 to 10 times the molar amount, the maximum fluorescence emission intensity of the compound at around 565 nm gradually decreased or was even completely quenched; then the Fe 3+ When the concentration is from 10 to 20 times the molar amount, the fluorescence emission spectrum remains basically unchanged. For specific results, see Figure 5 , indicating that the thiadiazole-diethylamino salicylimine molecule has a strong affinity for Fe 3+ It has sensitive fluorescence "off-on" detection performance.

[0062] Example 6

[0063] Effect of Thiadiazole-Diethylamino Salicylimide Molecular Solution on Ni 2+ Ion fluorescence detection function: in 90% DMF aqueous solution, the concentration is 1×10 -5 mol / L thiadiazole-diethylamino salicylimine molecules and different concentrations of Ni 2+ The fluorescence emission spectra in the presence of Ni ions are as follows: in the free state, the maximum emission of the imine molecular sensor is around 565 nm; when different concentrations of Ni are added, the fluorescence emission spectra of the imine molecular sensor ... 2+ After that, the fluorescence emission intensity decreased significantly between 0-1.8 times the molar equivalent, decreasing by 78%. 2+ The fluorescence emission intensity decreased slightly and remained basically unchanged at the concentration of 10 times the molar equivalent. Figure 6 , indicating that the thiadiazole-diethylamino salicylimine molecule and Ni 2+ There is good complexing performance between them, and Ni 2+ It has fluorescence emission "on-off" signal recognition performance.

[0064] Example 7

[0065] Thiadiazole-diethylamino salicylimide molecular solution for Co 2+ Ion fluorescence detection function: in 90% DMF aqueous solution, the concentration is 1×10 -5 mol / L thiadiazole-diethylamino salicylimine molecules and different concentrations of Co 2+ The fluorescence emission spectrum in the presence of Co ions is as follows: 2+ As the concentration increased from 0 to 1.4 times the molar equivalent, the maximum fluorescence emission intensity of the imine molecular sensor at around 565 nm decreased significantly, by 80%; 2+When the concentration reaches 10 times the molar equivalent, the fluorescence intensity decreases slowly and then remains basically unchanged. For specific results, see Figure 7 , indicating that the thiadiazole-diethylamino salicylimine molecule has a strong affinity for Co 2+ It has fluorescence emission "on-off" signal recognition performance.

[0066] Example 8

[0067] Optical detection function of thiadiazole-diethylamino salicylimine molecular solution in different alkaline environments: in 90% DMF aqueous solution, the concentration is 1×10 -5 The UV absorption spectra of 1 mol / L thiadiazole-diethylamino salicylimine molecules mixed with different concentrations of NaOH for 5 minutes are as follows: As the NaOH concentration increases from 0 to 200 times the molar equivalent, the maximum absorption of the thiadiazole-diethylamino salicylimine molecule at 496 nm first decreases, then increases and red-shifts to 538 nm. Figure 8 The fluorescence emission spectrum of thiadiazole-diethylamino salicylimine in the presence of different concentrations of base showed that as the concentration of sodium hydroxide increased from 0 to 200 times the molar equivalent, the maximum fluorescence emission of the molecule near 565 nm gradually decreased and was quenched. For specific results, see Figure 9 This indicates that the thiadiazole-diethylamino salicylimine molecule not only has a sensitive UV dynamic response to different alkaline environments, but also has the potential for dual detection of fluorescence "off-on" signals.

[0068] Example 9

[0069] Optical detection function of thiadiazole-diethylamino salicylimine molecular solution in different acidic environments: in 90% DMF aqueous solution, the concentration was 1×10 -5 The UV absorption spectra of 10 mol / L thiadiazole-diethylamino salicylimine molecules after 5 minutes of mixing with different concentrations of HCl are as follows: When the HCl concentration is increased from 0 to 100 times the molar equivalent, the maximum absorption of the molecule at 496 nm shifts to the blue, and the absorbance gradually decreases, while the absorption around 345 nm gradually increases. Figure 10 The fluorescence emission spectrum of the mixed system showed that as the HCl concentration increased from 0 to 100 times the molar equivalent, the fluorescence emission of the thiadiazole-diethylamino salicylimine molecule at around 565 nm gradually decreased and was quenched. For specific results, see Figure 11 This indicates that the thiadiazole-diethylamino salicylimide molecule has ultraviolet double-peak absorption changes and fluorescence emission "on-off" signal properties in response to different acidic environment changes.

[0070] Example 10

[0071] Performance of two-component gel formed by thiadiazole-diethylamino salicylimide molecules: The gel was prepared by the "heating-low-temperature ultrasonic cooling" method, with thiadiazole-diethylamino salicylimide molecules (TS) and cholesterol half ester gelator (CS) as the two-component gel factors. According to the TS:CS molar mass ratio of 1:35, 0.5 mg of TS and the corresponding amount of CS gelator were weighed and placed in a 2 mL glass vial. 0.3 mL of tert-butanol was added and heated until the two-component gel factors were completely dissolved. The gel was then ultrasonically cooled at about -5°C for 2 min to form a two-component gel TSCS that emitted orange-yellow fluorescence under sunlight and orange-red fluorescence under ultraviolet light. Figure 12 Field emission scanning electron microscopy (SEM) was used to characterize the micromorphology of the TSCS two-component xerogel. It was found that in the tert-butyl alcohol system, the TSCS two-component self-assembled gel exhibited a fiber-rod network structure that was intertwined and interwoven. Figure 13 .

[0072] Example 11

[0073] Detection performance of the two-component gel TSCS in acidic environments: After adding 0.1 mol / L HCl solution to the TSCS two-component gel, the orange-yellow gel turned milky white under sunlight, and the orange-red fluorescence emission of the two-component gel disappeared under 365 nm ultraviolet light (Figure 14), indicating that the TSCS two-component gel has intuitive and rapid dual-signal detection performance in acidic environments such as HCl.

[0074] Example 12

[0075] Detection performance of the two-component gel TSCS in alkaline environments: After adding 0.1 mol / L NaOH dilution to the TSCS two-component gel, the orange-yellow gel turned milky white under sunlight. Under irradiation with a 365 nm ultraviolet lamp, the orange-red fluorescence emission of the two-component gel turned into a gel with no fluorescence emission (Figure 15). This shows that the TSCS two-component gel has in-situ, real-time, on-site, intuitive, and rapid dual-signal detection performance in alkaline environments such as NaOH.

[0076] Example 13

[0077] Two-component gel TSCS for Fe 3+ 、Co 2+ 、Ni 2+ Detection performance: The orange-yellow TSCS two-component gel was first prepared in tert-butyl alcohol by the "heating-low temperature ultrasonic cooling" method; then 0.1 mol / LFe 3+ 、Co 2+ 、Ni 2+ The solutions were added dropwise to the above gels: Under sunlight, Fe 3+ After adding, the orange gel turns white. 2+After adding, the orange gel turns reddish brown. 2+ After the addition, the orange gel turned into transparent red, Figure 16; under 365 nm UV light, Fe 3+ 、Co 2+ 、Ni 2+ After addition, its orange-red fluorescence emission disappeared, Figure 17. These studies show that TSCS two-component gel has a strong effect on Fe 3+ 、Co 2+ 、Ni 2+ It has intuitive signal and fast dual detection performance.

Claims

1. An imine molecular sensor with five detection functions, the sensor is a symmetrical thiadiazole-diethylamino salicylimine molecule, and its structure is: 。 2. An imine molecular sensor as claimed in claim 1 in Co 2+ 、Ni 2+ Applications in detection, which do not involve the diagnosis and treatment of diseases, are characterized by: The imine molecular sensor is used for the three-signal detection of Co by fluorescence emission "on-off", ultraviolet absorption red shift and direct emission color change. 2+ ; The imine molecular sensor is used for the three-signal detection of Ni by fluorescence emission "on-off", ultraviolet absorption red shift and direct emission color change. 2+ .

3. An application of the imine molecular sensor according to claim 1 in acidic environment detection, characterized in that: As the concentration of HCl increases, the maximum absorption of the imine molecular sensor at 496 nm shifts to the blue and the absorbance gradually decreases, while the absorption near 345 nm gradually increases, and the maximum fluorescence emission near 565 nm is quenched.

4. An application of the imine molecular sensor according to claim 1 in alkaline environment detection, characterized in that: As the amount of NaOH added increases, the maximum absorption of the imine molecular sensor at 496 nm first decreases, then increases and red-shifts to 538 nm. At the same time, the maximum fluorescence emission of the molecule near 565 nm gradually decreases and is quenched.

5. A method for preparing a two-component gel, characterized in that: A heating-low-temperature ultrasonic cooling gelation method is adopted, wherein the imine molecular sensor according to claim 1 and the cholesterol half ester gelator are mixed in a molar mass ratio of 1:35, tert-butanol solvent is added, and the mixture is heated until the two-component gel factor is completely dissolved, and then ultrasonically cooled at about -5°C for 2 minutes to form a two-component gel material. 6 . A two-component gel comprising an imine molecular sensor prepared by the preparation method according to claim 5 .

7. Use of the two-component gel comprising an imine molecular sensor as claimed in claim 5 in acidic environment detection, characterized in that: After the addition of HCl, the orange-yellow color of the two-component gel changes to milky white under sunlight, and the orange-red fluorescence emission disappears under 365 nm ultraviolet light.

8. Use of the two-component gel comprising an imine molecular sensor as claimed in claim 5 in alkaline environment detection, characterized in that: After the addition of NaOH, the orange-yellow color of the two-component gel changes to milky white under sunlight, and the orange-red fluorescence emission disappears under 365 nm ultraviolet light.

9. A two-component gel comprising an imine molecular sensor as claimed in claim 5 in Co 2+ 、Ni 2+ Applications in detection, which do not involve the diagnosis and treatment of diseases, are characterized by: Co 2+ After the addition, the orange-yellow color of the two-component turns reddish brown under sunlight, and its orange-red fluorescence emission disappears under 365 nm ultraviolet light. Ni 2+ After the addition, the orange-yellow color of the two-component gel changes to transparent red under sunlight, and the orange-red fluorescence emission disappears under irradiation with a 365 nm ultraviolet lamp.

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