An asymmetric imine molecular sensor with six detection functions regulated by solvent and a preparation method and application thereof

Abstract

The present application relates to the technical field of organic small molecule material detection, in particular to a solvent-regulated six-detection-function asymmetric imine molecular sensor, a preparation method and application thereof. The imine molecular sensor exhibits different fluorescence "on-off" detection responses, fluorescence "on-off" and absorption change double signal responses to acidic environment changes in 90% CH3CN aqueous solution 2+ / Co 2+ / Mn 2+ ; different fluorescence "on-off" responses, fluorescence "on-off" and absorption double signal detection performances to basic environment changes in 90% DMF aqueous solution 3+ / Cu 2+ ; and fluorescence different "on-off" detection performances of the binary system formed by the imine molecular sensor and Co 2+ / Mn 2+ to Cu 2+ , which is fast and sensitive. The imine molecular sensor provided by the present application has the advantages of mild synthesis conditions and simple preparation, thus creating favorable conditions for its popularization and application.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of organic small molecule material detection, and particularly relates to a non-symmetrical imine molecular sensor capable of sensitive detection of Fe 3+ , Cu 2+ , Co 2+ , Mn 2+ , acid and base environment changes and application. BACKGROUND

[0002] The rapid development of China's metal industry is driven by scientific and technological progress, and the related environmental pollution brought by the development of the metal industry restricts its sustainable development. The metal industry is complex, with various processes and large amounts of pollution factors. The smelting process produces a large amount of heavy metal pollutants. Because metal ions are not easy to be degraded, they are easily enriched and expanded in the biological chain, and their pollution has the characteristics of concealment, accumulation and irreversibility. Once discharged into the environment, they can form a complex, dynamic and long-chain migration system, causing great harm to the ecological system and human living environment. Irrigating land with wastewater containing excessive amounts of heavy metal ions can not only lead to a decrease in crop yield and quality, but also cause plants to wither and die. Although metals in the soil are not easy to be decomposed or disappear, they can be easily absorbed by organisms, causing food pollution. Once people eat water and food contaminated by metal ions, the metal ions will accumulate in the body, causing serious harm to the human body. In the pollution prevention and control process, accurate and rapid detection of metal ion pollutants, especially accurate and rapid detection of their pollution sources, is of great significance to effectively prevent and control heavy metal pollution and protect the health of the people.

[0003] Current metal ion detection methods include atomic absorption, atomic fluorescence spectroscopy, high-performance liquid chromatography and gas chromatography, inductively coupled plasma mass spectrometry, etc. Although these analysis methods can accurately detect the content of metal ions, they have limitations such as expensive instruments, complex operation, long detection time, high requirements for detection and analysis personnel, and high detection cost. Fluorescent molecular sensors rely on the fluorescence change response of photosensitizers to the measured substance, and realize qualitative and visual detection of the measured substance at the molecular level. The results are accurate and sensitive, and fluorescent molecular sensors have become an important technology for detecting metal ions and have been widely used in industrial and agricultural production, environmental engineering, etc. However, most fluorescent molecular sensors currently only show sensitive detection performance for a specific metal ion, have single functions, and have large application limitations. Moreover, they have the characteristics of complex preparation process, low yield and high cost, which makes it difficult to meet the growing market demand. Multifunctional fluorescent molecular sensors not only avoid the preparation process of multiple single molecular sensors, but also have higher detection efficiency than single-function molecular sensors. However, there are relatively few multifunctional fluorescent molecular sensors, and they are less used in metal pollution detection, especially in on-site analysis of pollution sources.

[0004] In addition, with the rapid development of society, various waste acids and alkalis generated in the process of industrial and agricultural production are increasing; when these untreated acids or alkalis are directly discharged into the soil, they can cause changes in the surrounding environment, causing plants to wither and animals to die, and causing great harm to human production and life. Therefore, in the field of industrial and agricultural production, sensitive analysis and testing technology is needed to monitor the discharge of acid and alkali liquids that can pollute the water and soil resources on which people depend. At the same time, the industrial and agricultural production processes that can only be carried out in a specific acid or alkaline environment also need efficient pH detection technology to track, improve product quality and work efficiency. Fluorescent molecular sensors have become a powerful tool for detecting pH changes in various fields due to their high sensitivity, good selectivity, and simple operation. However, most of the reported pH molecular sensors have a single direction of fluorescence signal change, i.e. with increasing / decreasing acidity, the fluorescence shows a single signal change of "off-on" or "on-off", while the demand for dynamic pH change detection in people's work and life is increasing. Therefore, developing pH molecular sensors that are easy to prepare, sensitive and fast, and have a wide range of practical applications is an urgent need in various monitoring fields.

[0005] The imine-C=N-group is easy to synthesize and has strong proton complexing ability, and the p-π conjugation after connecting with the fluorophore can increase the conjugation of the fluorescent molecule; when the nitrogen atom in the-C=N-group is complexed with a proton, it can induce sensitive fluorescence intensity or dual-channel spectral changes. As a multi-site modified bridging group, the imine molecular sensor constructed by diamino maleonitrile has also attracted more and more attention [Y. Kang, Z. Liao, M. Wu, S. Li, D.-C. Fang, X.-J. Zheng, L.-P. Jin, Dalton Trans ., 2018, 47, 13730–13738; H. Zhou a, J. Wang, Y. Chen, W. Xi, Z. Zheng, D. Xu, Y. Cao, G. Liu, W. Zhu, J. Wu, Y. Tian, Dyes and Pigments, 2013, 98, 1-10]. However, a molecular sensor with six detection functions for Fe 3+ , Cu 2+ , Co 2+ , Mn 2+ and changes in acid-base environment has not been developed. SUMMARY

[0006] In view of the problems in the prior art, the present application provides a solvent-regulated Fe3+ Cu 2+ Co 2+ Mn 2+ and acid, base environment change has six detection function's molecular sensor, the molecular sensor is asymmetric trifluoromethyl benzene-maleic nitrile-diethyl amino salicylic molecule.

[0007] The present application is realized by the following technical solutions:

[0008] A solvent regulated six detection function's molecular sensor, the sensor is asymmetric trifluoromethyl benzene-maleic nitrile-diethyl amino salicylic molecule, and its structure is: .

[0009] The molecular sensor is easy to prepare, and has different optical detection signals for Fe 3+ Cu 2+ Co 2+ Mn 2+ , acid and base environment change, and can realize fast and accurate detection of different systems Fe 3+ Cu 2+ Co 2+ Mn 2+ , acid and base environment change.

[0010] Another object of the present application is to provide a preparation method of the asymmetric trifluoromethyl benzene-maleic nitrile-diethyl amino salicylic molecule, comprising the following steps:

[0011] S1. Put the diamino maleic nitrile into a round-bottom flask containing anhydrous ethanol, and sequentially add 4-diethyl amino salicylaldehyde and glacial acetic acid, and heat to reflux for 4 hours. The reaction mixture is filtered, washed with anhydrous ethanol, and dried to obtain a red single amino maleic nitrile-4-diethyl amino salicylic compound;

[0012] S2. Put the single amino maleic nitrile-4-diethyl amino salicylic compound obtained in step S1 into a dichloromethane-anhydrous ethanol mixed solvent, and add 4-trifluoromethyl benzaldehyde and concentrated sulfuric acid, and heat to reflux for 4-6 hours. The reaction mixture is filtered, washed with anhydrous ethanol, and dried to obtain a black green trifluoromethyl benzene-maleic nitrile-diethyl amino salicylic compound.

[0013] Further, in step S2, the molar ratio of the single amino maleic nitrile-4-diethyl amino salicylic compound and 4-trifluoromethyl benzaldehyde is 1:1, the volume ratio of dichloromethane and anhydrous ethanol in the mixed solvent is 1:4, the addition amount of the mixed solvent is limited to 30 mL of mixed solvent per 1 mmol of single amino maleic nitrile-4-diethyl amino salicylic compound, and the addition amount of the concentrated sulfuric acid is 100 μL of concentrated sulfuric acid per 1 mmol of 4-trifluoromethyl benzaldehyde.

[0014] The preparation reaction formula of the trifluoromethyl benzene-maleonitrile-diethylaminosalicylic molecular sensor is as follows:

[0015] .

[0016] A third object of the present application is to provide the application of the trifluoromethyl benzene-maleonitrile-diethylaminosalicylic molecule in the detection of Cu 2+ , Co 2+ , Mn 2+ .

[0017] The specific performance is as follows: in 90% CH3CN aqueous solution, the asymmetric molecular sensor has a strong maximum fluorescence emission near 623 nm; after adding 10 times of Co 2+ , the maximum fluorescence emission intensity is reduced by 51%; after adding 10 times of Mn 2+ , the maximum fluorescence emission intensity is reduced by 75%; after adding 10 times of Cu 2+ , the maximum fluorescence emission is quenched; after adding other metal ions, the maximum fluorescence emission of the asymmetric molecular sensor does not change obviously.

[0018] A fourth object of the present application is to provide the application of the trifluoromethyl benzene-maleonitrile-diethylaminosalicylic molecule in the detection of Fe 3+ , Cu 2 + .

[0019] The specific performance is as follows: in 90% DMF aqueous solution, the asymmetric molecular sensor has a strong maximum fluorescence emission near 633 nm; after adding 10 times of Fe 3+ , the maximum fluorescence emission intensity is reduced by 65%; after adding 10 times of Cu 2+ , the maximum fluorescence emission intensity is reduced by 82%; after adding other metal ions, the maximum fluorescence emission of the molecular sensor does not change obviously.

[0020] A fifth object of the present application is to provide the application of the trifluoromethyl benzene-maleonitrile-diethylaminosalicylic molecule in the detection of acidic environment.

[0021] The specific performance is as follows: in 90% CH3CN aqueous solution, with the gradual increase of the amount of HCl, the maximum fluorescence emission of the asymmetric molecular sensor near 623 nm is red-shifted to near 629 nm, accompanied by a decrease of 80% in emission intensity, at the same time, the maximum absorption at 560 nm is gradually reduced and disappears, at the same time, a weak absorption peak near 350 nm appears, which endows the asymmetric molecular sensor with the fluorescence “off-on” and UV absorption dual signal detection performance in acidic environment.

[0022] The sixth object of the present application is to provide the trifluoromethyl benzene-maleonitrile-diethylaminosalicylate molecule pair for the basic environment detection application.

[0023] The specific performance is as follows: in 90% DMF aqueous solution, with the gradual increase of the amount of NaOH, the asymmetric molecule sensor is red-shifted from the maximum fluorescence emission near 633 nm to the maximum fluorescence emission near 640 nm, accompanied by a gradual decrease of 76% in fluorescence emission intensity, and at the same time, the maximum absorption is red-shifted from 570 nm to 600 nm, which endows the asymmetric molecule sensor with the fluorescence "off-on" and absorption double signal detection performance for the acidic environment.

[0024] Compared with the prior art, the present application has the following technical effects: the trifluoromethyl benzene-maleonitrile-diethylaminosalicylate molecule sensor has a strong coordination ability to metal ions at multiple sites such as imine and hydroxyl groups, and the imine group can induce sensitive optical signal changes after participating in coordination, so that it exhibits different fluorescence emission "on-off" detection responses in 90% CH3CN aqueous solution for Fe 2+ / Co 2+ / Mn 2+ , and different fluorescence emission "on-off" signal responses in 90% DMF aqueous solution for Fe 3+ / Cu 2+ ; the imine molecule sensor exhibits fluorescence "on-off" and absorption change double signal detection performance for the acidic environment in 90% CH3CN aqueous solution and for the basic environment in 90% DMF aqueous solution; the binary system formed by the imine molecule sensor and Co 2+ / Mn 2+ has different fluorescence "on-off" signal detection performance for Cu 2+ , which endows the imine monomolecular sensor with the detection function for Fe 3+ / Cu 2+ / Co 2+ / Mn 2+ / acid / base six targets and four analysis detection characteristics for Cu 2+ , which is fast, sensitive and has high application value; the trifluoromethyl benzene-maleonitrile-diethylaminosalicylate molecule sensor provided by the present application has the advantages of high yield and mild synthesis conditions, and is suitable for industrial implementation, which creates favorable conditions for the popularization and application of the trifluoromethyl benzene-maleonitrile-diethylaminosalicylate molecule sensor. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 It is the nuclear magnetic resonance spectrum of the trifluoromethyl benzene-maleonitrile-diethylaminosalicylate molecule.

[0026] Figure 2The fluorescence emission detection performance of the trifluoromethyl benzene-maleonitrile-diethylaminosalicylic molecule in 90% CH3CN aqueous solution on different metal ions.

[0027] Figure 3 The photos under the ultraviolet lamp after the trifluoromethyl benzene-maleonitrile-diethylaminosalicylic molecule in 90% CH3CN aqueous solution reacts with different metal ions.

[0028] Figure 4 The fluorescence emission spectrum of the trifluoromethyl benzene-maleonitrile-diethylaminosalicylic molecule in 90% CH3CN aqueous solution after reacting with different concentrations of copper.

[0029] Figure 5 The photos under the ultraviolet lamp after the trifluoromethyl benzene-maleonitrile-diethylaminosalicylic molecule in 90% CH3CN aqueous solution reacts with different concentrations of copper.

[0030] Figure 6 The fluorescence emission detection performance of the trifluoromethyl benzene-maleonitrile-diethylaminosalicylic molecule in 90% CH3CN aqueous solution on Co 2+ Competitive selection performance with other metal ions.

[0031] Figure 7 The fluorescence emission detection performance of the trifluoromethyl benzene-maleonitrile-diethylaminosalicylic molecule in 90% CH3CN aqueous solution on Mn 2+ Competitive selection performance with other metal ions.

[0032] Figure 8 The fluorescence emission detection performance of the trifluoromethyl benzene-maleonitrile-diethylaminosalicylic molecule in 90% CH3CN aqueous solution on Cu 2+ Competitive selection performance with other metal ions.

[0033] Figure 9 The fluorescence emission detection performance of the trifluoromethyl benzene-maleonitrile-diethylaminosalicylic molecule in 90% DMF aqueous solution on different metal ions.

[0034] Figure 10 The fluorescence emission performance of the trifluoromethyl benzene-maleonitrile-diethylaminosalicylic molecule in 90% CH3CN aqueous solution after reacting with different concentrations of HCl.

[0035] Figure 11 The ultraviolet absorption performance of the trifluoromethyl benzene-maleonitrile-diethylaminosalicylic molecule in 90% CH3CN aqueous solution after reacting with different concentrations of HCl.

[0036] Figure 12 The fluorescence emission performance of the trifluoromethyl benzene-maleonitrile-diethylaminosalicylic molecule in 90% DMF aqueous solution after reacting with different concentrations of HCl.

[0037] Figure 13The UV absorption performance of the trifluoromethyl benzene-maleonitrile-diethylaminosalicylic molecule in 90% DMF aqueous solution is affected by different concentrations of HCl.

[0038] Figure 14 The fluorescence emission performance of the trifluoromethyl benzene-maleonitrile-diethylaminosalicylic molecule in 90% DMF aqueous solution is affected by different concentrations of NaOH.

[0039] Figure 15 The UV absorption performance of the trifluoromethyl benzene-maleonitrile-diethylaminosalicylic molecule in 90% DMF aqueous solution is affected by different concentrations of NaOH. DETAILED DESCRIPTION

[0040] The disclosed trifluoromethyl benzene-maleonitrile-diethylaminosalicylic molecule sensor with solvent regulation six detection functions has a molecular structure as follows: .

[0041] The trifluoromethyl benzene-maleonitrile-diethylaminosalicylic molecule can be prepared by using 4-diethylaminosalicylaldehyde, diamino maleonitrile and 4-trifluoromethyl benzaldehyde as raw materials through a two-step polymerization reaction, and the synthesis reaction formula is as follows: .

[0042] Example 1

[0043] Preparation of compound A: 1 mmol of 4-diethylaminosalicylaldehyde was placed in a round-bottom flask containing 15 mL of anhydrous ethanol, 1 mmol of diamino maleonitrile and 100 μL of glacial acetic acid were sequentially added, and the reaction was carried out at reflux for 4 hours; the obtained mixture was filtered, washed with anhydrous ethanol, and dried to obtain a single amino maleonitrile-4-diethylaminosalicylic compound with a meat red color;

[0044] 1 mmol of the single amino maleonitrile-4-diethylaminosalicylic compound was placed in a round-bottom flask containing 30 mL of a mixed solvent of dichloromethane and ethanol in a volume ratio of 1:4, 1 mmol of 4-trifluoromethyl benzaldehyde and 100 μL of concentrated sulfuric acid were added, and the reaction was carried out at reflux for 4 hours; the obtained mixture was filtered, washed with anhydrous ethanol, and dried to obtain a black green trifluoromethyl benzene-maleonitrile-diethylaminosalicylic compound A, 276.7 mg, with a yield of 63%.

[0045] Preparation of compound B: 1 mmol of 4-diethylaminosalicylaldehyde was placed in a round-bottom flask containing 15 mL of anhydrous ethanol, 1 mmol of diamino maleonitrile and 100 μL of glacial acetic acid were sequentially added, and the reaction was carried out at reflux for 4 hours; the obtained mixture was filtered, washed with anhydrous ethanol, and dried to obtain a single amino maleonitrile-4-diethylaminosalicylic compound with a meat red color;

[0046] The 1 mmol of monoamino maleonitrile-4-diethylamino salicylate compound was put into a 30 mL mixed solvent of dichloromethane-ethanol with a volume ratio of 1:4, 1 mmol of 4-trifluoromethyl benzaldehyde, 100 μL of concentrated sulfuric acid were added, and the reaction was carried out at reflux for 6 hours; the reaction mixture was filtered, washed with anhydrous ethanol, and dried to obtain black green trifluoromethyl benzene-maleonitrile-diethylamino salicylate compound B, 285.4 mg, with a yield of 65%.

[0047] The compounds A and B obtained in Examples 1 and 2, respectively, were analyzed and measured, and the nuclear magnetic resonance (NMR) data of the two were as follows: Figure 1 Figure 1 1 H NMR (400 MHz, CDCl3) δ 12.85 (s, 1H), 8.55 (d, 2H), 7.26 (m,4H), 6.43 (t, 3H), 3.49 (m, 4H), 3.28 (t, 2H), 1.28 (m, 6H);MS: ion peak m / z 439.45, [theoretical calculation value M + 439.16];indicating that the compound A / B is basically consistent with the theoretical value of trifluoromethyl benzene-maleonitrile-diethylamino salicylate compound. It can be confirmed that the molecular structure of the compound A and B is:

[0048] trifluoromethyl benzene-maleonitrile-diethylamino salicylate molecule.

[0049] Example 3

[0050] The fluorescence detection function of the trifluoromethyl benzene-maleonitrile-diethylamino salicylate molecule sensor on different metal ions in 90% CH3CN aqueous solution: in 90% CH3CN aqueous solution, the trifluoromethyl benzene-maleonitrile-diethylamino salicylate molecule sensor with a concentration of 1×10 -5 mol / L has a maximum fluorescence emission near 623 nm; after 10 times of Co 2+ is added, the maximum fluorescence emission intensity decreases by 51%; after 10 times of Mn 2+ is added, the maximum fluorescence emission intensity decreases by 75%; after 10 times of Cu 2+ is added, the maximum fluorescence emission is quenched; other metal ions such as K + , Mg 2+ , Li + , Cr 3+ , Cd 2+ , Al 3+ , Hg 2+ , Pb 2+ , Zn 2+ , Ca​​2+ , Ba 2+ , Na + and Ni 2+ , the fluorescence emission spectrum of the trifluoromethylbenzene-maleonitrile-diethylaminosalicylic molecule sensor did not change significantly, and the specific results are shown in Figure 2 . Under the irradiation of a 365 nm ultraviolet (UV) lamp, the trifluoromethylbenzene-maleonitrile-diethylaminosalicylic molecule sensor solution emitted red fluorescence. When Co 2+ , Mn 2+ was added, the red fluorescence emission was weakened, when Cu 2+ was added, the red fluorescence emission disappeared, and when other metal ions were added, the red fluorescence emission was basically unchanged, and the specific results are shown in Figure 3 . These results show that the trifluoromethylbenzene-maleonitrile-diethylaminosalicylic molecule sensor has sensitive and intuitive fluorescence “off-on” detection potential for Co 2+ , Mn 2+ , and Cu 2+ .

[0051] Example 4

[0052] Fluorescence detection function of the trifluoromethylbenzene-maleonitrile-diethylaminosalicylic molecule sensor for different concentrations of Cu 2+ ions: In 90% CH3CN aqueous solution, when the trifluoromethylbenzene-maleonitrile-diethylaminosalicylic molecule sensor with a concentration of 1 × 10 -5 mol / L was present with different concentrations of Cu 2+ , the fluorescence emission spectrum was as follows: as the Cu 2+ concentration increased from 0 to 4 times the molar amount, the maximum fluorescence emission intensity of the compound gradually decreased, and was even completely quenched; after the Cu 2+ concentration continued to increase even to 10 times the molar amount, the fluorescence emission spectrum was basically unchanged, and the specific results are shown in Figure 4 ; under the irradiation of a 365 nm ultraviolet (UV) lamp, as the Cu 2+ concentration increased from 0 to 4 times the molar amount, the red fluorescence emission of the trifluoromethylbenzene-maleonitrile-diethylaminosalicylic molecule sensor solution gradually weakened and disappeared, and the specific results are shown in Figure 5 , indicating that the trifluoromethylbenzene-maleonitrile-diethylaminosalicylic molecule sensor has sensitive and intuitive fluorescence “off-on” recognition potential for Cu 2+ .

[0053] Example 5

[0054] Co 2+Optical competitiveness with other metal ions: In a 90% CH3CN aqueous solution, at a concentration of 1×10⁻⁶ -5 Adding 10 times the amount of Co to a mol / L trifluoromethylbenzene-maleonitrile-diethylaminosalicylic acid molecule 2+ Fluorescence emission spectroscopy studies of mixed systems with other different metal ions show that adding 10 times the amount of Co to the trifluoromethylbenzene-maleonitrile-diethylaminosalicylic acid molecule... 2+ Subsequently, the binary system exhibits a weak maximum fluorescence emission near 623 nm; when K... + Mg 2+ Li + Co 2+ Cr 3+ Cd 2+ Al 3+ Hg 2+ Pb 2+ Ca 2+ Ba 2+ Na + and Ni 2+ Metal ions and Co 2+ Simultaneous addition of a trifluoromethylbenzene-maleonitrile-diethylaminosalicylic acid molecular solution to the ternary mixture system and the molecular sensor-Co 2+ The fluorescence emission spectra of the binary system are similar; however, this molecular sensor -Co 2+ Adding Cu to a binary system 2+ Subsequently, the fluorescence emission of the mixed system was quenched; see the detailed results below. Figure 6 These indicate that the trifluoromethylbenzene-maleonitrile-diethylaminosalicylic acid molecule not only affects Co 2+ It exhibits good selective detection performance, compared with Co 2+ Binary system for Cu 2+ It has fluorescence "on-off" detection performance.

[0055] Example 6

[0056] Mn in a trifluoromethylbenzene-maleonitrile-diethylaminosalicylic acid molecular sensor 2+ Spectroscopic competitiveness with other metal ions: In a 90% CH3CN aqueous solution, at a concentration of 1×10⁻⁶ -5 Adding 10 times the amount of Mn to a mol / L trifluoromethylbenzene-maleonitrile-diethylaminosalicylic acid molecule 2+ Fluorescence emission spectroscopy studies of mixed systems with other different metal ions show that adding 10 times the amount of Mn to the trifluoromethylbenzene-maleonitrile-diethylaminosalicylic acid molecule... 2+ Subsequently, the binary system exhibits a weak maximum fluorescence emission near 622 nm; when K... + Mg 2+ Li + Co2+ Cr 3+ Cd 2+ Al 3+ Hg 2+ Pb 2+ Ca 2+ Ba 2+ Na + and Ni 2+ Metal ions and Mn 2+ Simultaneous addition of a trifluoromethylbenzene-maleonitrile-diethylaminosalicylic acid molecule solution results in a fluorescence emission spectrum of the ternary system that is in contrast to the trifluoromethylbenzene-maleonitrile-diethylaminosalicylic acid molecule-Mn 2+ The fluorescence spectra of the binary system are similar; however, when Cu is added to this binary system... 2+ Subsequently, the fluorescence emission of the mixed system was quenched; see the detailed results below. Figure 7 These indicate that the trifluoromethylbenzene-maleonitrile-diethylaminosalicylic acid molecule not only affects Mn 2+ It exhibits good selective detection performance, compared with Mn 2+ Binary system for Cu 2+ It has fluorescence "on-off" detection performance.

[0057] Example 7

[0058] Cu in trifluoromethylbenzene-maleonitrile-diethylaminosalicylic acid molecular sensor 2+ Spectroscopic competitiveness with other metal ions: In a 90% CH3CN aqueous solution, at a concentration of 1×10⁻⁶ -5 Adding 10 times the amount of Cu to a mol / L trifluoromethylbenzene-maleonitrile-diethylaminosalicylic acid molecule 2+ Fluorescence emission spectroscopy studies of mixed systems with other different metal ions show that adding 10 times the amount of Cu to the trifluoromethylbenzene-maleonitrile-diethylaminosalicylic acid molecule... 2+ Afterwards, the fluorescence emission of the molecular sensor was almost completely quenched; when K... + Mg 2+ Li + Co 2+ Cr 3+ Cd 2+ Al 3+ Hg 2+ Pb 2+ Ca 2+ Ba 2+ Na + and Ni 2+ Metal ions and Cu 2+ Simultaneous addition of a trifluoromethylbenzene-maleonitrile-diethylaminosalicylic acid molecule solution resulted in almost no fluorescence emission in the ternary system, and the system reacted with the trifluoromethylbenzene-maleonitrile-diethylaminosalicylic acid molecule-Cu. 2+The binary system fluorescence spectrum is similar, and the specific results are shown in Figure 8 . These show that the trifluoromethyl benzene-maleonitrile-diethylaminosalicylic molecule has good selective detection performance on Cu 2+ .

[0059] Example 8

[0060] The fluorescence detection function of the trifluoromethyl benzene-maleonitrile-diethylaminosalicylic molecule sensor on different metal ions in 90% DMF aqueous solution: in 90% DMF aqueous solution, the trifluoromethyl benzene-maleonitrile-diethylaminosalicylic molecule sensor with a concentration of 1 × 10 -5 mol / L has a maximum fluorescence emission near 633 nm; after the addition of 10 times Fe 3+ , the maximum fluorescence emission intensity decreases by 65%; after the addition of 10 times Cu 2+ , the maximum fluorescence emission intensity decreases by 82%; after the addition of other metal ions such as K + , Mg 2+ , Li + , Cr 3+ , Cd 2+ , Al 3+ , Hg 2+ , Pb 2+ , Zn 2+ , Mn 2+ , Co 2+ , Ca 2+ , Ba 2+ , Na + and Ni 2+ , the fluorescence emission of the trifluoromethyl benzene-maleonitrile-diethylaminosalicylic molecule changes little, and the specific results are shown in Figure 9 . These results show that the trifluoromethyl benzene-maleonitrile-diethylaminosalicylic molecule sensor has different fluorescence “on-off” detection potential for Fe 3+ , Cu 2+ .

[0061] Example 9

[0062] The optical detection function of the trifluoromethyl benzene-maleonitrile-diethylaminosalicylic molecule sensor on different acidic environments in 90% CH3CN aqueous solution: in 90% CH3CN aqueous solution, the fluorescence emission spectrum of the trifluoromethyl benzene-maleonitrile-diethylaminosalicylic molecule with a concentration of 1 × 10 -5 mol / L in the presence of different concentrations of HCl is as follows: as the concentration of HCl added increases from 0 to 100 times the molar equivalent, the maximum fluorescence emission of the molecule sensor near 623 nm red shifts to 629 nm, and the fluorescence emission intensity decreases by 80%, and the specific results are shown in Figure 10UV-Vis absorption spectral properties studies show that with the increase of HCl concentration from 0 to 100 times molar amount, the maximum absorption of the molecular sensor around 560 nm disappears, and a new weak absorption around 350 nm appears; then continue to increase the HCl concentration even to 300 times molar amount, its UV-Vis absorption spectrum is basically unchanged, see Figure 11 for details. These results show that the trifluoromethylbenzene-maleonitrile-diethylaminosalicylic molecular sensor has sensitive fluorescence "on-off" and UV-Vis absorption double peak ratio dual signal detection potential for changes in acidic environment in 90% CH3CN aqueous solution.

[0063] Example 10

[0064] Optical detection function of trifluoromethylbenzene-maleonitrile-diethylaminosalicylic molecular sensor for different acidic environments in 90% DMF aqueous solution: In 90% DMF aqueous solution, the fluorescence emission spectrum of trifluoromethylbenzene-maleonitrile-diethylaminosalicylic molecule with a concentration of 1 × 10 -5 mol / L in the presence of different concentrations of HCl is as follows: with the increase of HCl concentration from 0 to 300 times molar equivalent, the maximum fluorescence emission intensity of the molecular sensor around 633 nm decreases by 25%, see Figure 12 for details. UV-Vis absorption spectral properties studies show that with the increase of HCl concentration from 0 to 300 times molar amount, the maximum absorption of the molecular sensor around 570 nm slightly decreases, see Figure 13 for details. It shows that the trifluoromethylbenzene-maleonitrile-diethylaminosalicylic molecular sensor has no sensitive optical signal detection response for changes in acidic environment in 90% DMF aqueous solution.

[0065] Example 11

[0066] Optical detection function of trifluoromethylbenzene-maleonitrile-diethylaminosalicylic molecular sensor for different basic environments in 90% DMF aqueous solution: In 90% DMF aqueous solution, the fluorescence emission spectrum of trifluoromethylbenzene-maleonitrile-diethylaminosalicylic molecule with a concentration of 1 × 10 -5 mol / L in the presence of different concentrations of NaOH is as follows: with the increase of NaOH concentration from 0 to 150 times molar equivalent, the maximum fluorescence emission of the molecular sensor around 633 nm red shifts to 640 nm, and the fluorescence emission intensity decreases by 76%, see Figure 14 for details. UV-Vis absorption spectral properties studies show that with the increase of NaOH concentration from 0 to 150 times molar amount, the maximum absorption of the molecular sensor around 570 nm red shifts to around 600 nm, see Figure 15 for details. In 90% CH3CN aqueous solution, the fluorescence emission spectrum of trifluoromethylbenzene-maleonitrile-diethylaminosalicylic molecule with a concentration of 1 × 10 -5The maximum fluorescence emission of the sensor around 623 nm and the corresponding UV absorption spectrum changed little after adding 300 times molar equivalent of NaOH to the sensor. These indicated that the sensor had the potential to detect the basic environment in 90% DMF aqueous solution by fluorescence "on-off" and UV absorption double-peak ratio dual signal.

Claims

1. A solvent-regulated six-detection-function asymmetric imine molecular sensor, the sensor being an asymmetric trifluoromethyl benzene-maleonitrile-diethylaminosalicylic molecule, and the structure of the sensor being: comprising the following steps:

2. A method for preparing the asymmetric imine molecular sensor as described in claim 1, characterized in that: S1.placing diamino maleonitrile into a round-bottom flask containing anhydrous ethanol, sequentially adding 4-diethylaminosalicylaldehyde and glacial acetic acid, and heating to reflux for 4 hours; filtering, washing with anhydrous ethanol, and drying the obtained mixture to obtain a red single-amino maleonitrile-4-diethylaminosalicylic compound; S2.placing the single-amino maleonitrile-4-diethylaminosalicylic compound obtained in step S1 into a mixed solvent of dichloromethane and anhydrous ethanol, adding 4-trifluoromethyl benzaldehyde and concentrated sulfuric acid, and heating to reflux for 4-6 hours; filtering, washing with anhydrous ethanol, and drying the obtained mixture to obtain a black-green trifluoromethyl benzene-maleonitrile-diethylaminosalicylic molecular sensor. In step S2, the molar ratio of the single-amino maleonitrile-4-diethylaminosalicylic compound to 4-trifluoromethyl benzaldehyde is 1:1, the volume ratio of dichloromethane to anhydrous ethanol in the mixed solvent is 1:4, the addition amount of the mixed solvent is limited to 30 mL of the mixed solvent per 1 mmol of the single-amino maleonitrile-4-diethylaminosalicylic compound, and the addition amount of the concentrated sulfuric acid is 100 μL of the concentrated sulfuric acid per 1 mmol of the 4-trifluoromethyl benzaldehyde.

3. The method for preparing the asymmetric imine molecular sensor according to claim 2, characterized in that: ​ 4. Use of the asymmetric imine molecular sensor according to claim 1 in the detection of Cu 2+ not involving the diagnosis and treatment of diseases, characterized in that: In 90% aqueous CH3CN, the asymmetric imine molecular sensor binds to Co 2+ The constructed binary system was used for fluorescent "on-off" detection of Cu 2+ ; or in 90% aqueous CH3CN, the unsymmetrical imine molecular sensor with Mn 2+ The constructed binary system was used for fluorescent "on-off" detection of Cu 2+ .

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