Tri-state red light emission imine gelator, gel material, preparation method and application

Abstract

The invention relates to the technical field of organic supramolecular chemical materials, in particular to an imine gelator with tri-state red light emission, a three-dimensional network-shaped gel material of the imine gelator, a preparation method and application of the imine gelator. The gel factor is an asymmetric cholesterol-phenoxy-maleonitrile-diethylamino salicyl gel factor, and can be self-assembled in different solvents to form three-dimensional structure gel of a short rod shape, a fiber net shape and a flat strip shape; due to the highly conjugated asymmetric molecular structure, the fluorescent probe presents three-state red fluorescence emission in a solid state, a solution state and a gel state; the gelator shows intuitive colorimetric change and fluorescence'on-off 'double-signal detection performance on Fe < 3 + > and Co < 2 + > in toluene gel, and has colorimetric change, fluorescence'on-off' and gel-to-sol conversion three-signal response on Cu < 2 + >; the gelator has fluorescence'on-off 'detection response to Cu < 2 + > in a solution state, and double-state four-detection response performance to Cu < 2 + > is achieved; the gelator-Cu < 2 + > binary system has fluorescent on-off detection potential on Pb < 2 + >.

Description

Technical Field

[0001] The present invention relates to the technical field of supramolecular chemical materials, and in particular to an asymmetric imine gel factor with triple-state red light emission, a gel material thereof, and a preparation method and application thereof. Background Art

[0002] Organic small molecule gels, as smart soft materials, form a "jelly-like" three-dimensional network structure by entangling and immobilizing organic solvents with gelling agents. The driving force during self-assembly is primarily non-covalent forces, such as π-π interactions, hydrogen bonds, van der Waals forces, and hydrophilic-hydrophobic interactions. These intermolecular interactions are weak and are easily affected by external stimuli (such as light, electricity, pH, ions, and small molecules). Furthermore, organic small molecule gels often respond to external stimuli in ways that are visible to the naked eye, such as color changes (colorimetric responses) and gel-sol transitions (state responses). Furthermore, the structure of organic small molecule gelling agents is easily modifiable, allowing the introduction of specific functional groups at peripheral sites to construct intelligent organic small molecule gels that are characteristically responsive to external stimuli. Therefore, as a new type of smart soft material, organic small molecule gels offer excellent properties such as moderate flexibility and elasticity, rapid response to external stimuli, intuitive signal generation, high sensitivity, and simple operation, giving them broad application prospects in areas such as adsorption and separation, drug delivery, and optoelectronic devices. Organic small-molecule fluorescent gels are materials in which luminescent groups are embedded within a three-dimensional network structure, combining the dynamic reversibility and optical activity of gels. These materials can change the color or intensity of their luminescence in response to external stimuli (light, heat, chemicals, etc.), and possess advantages such as self-healing and biocompatibility. They are widely used in flexible displays, biomedical imaging, environmental sensing, and other fields, and are currently at the forefront of research at the intersection of materials science and chemistry. Organic small-molecule gel factors with red light emission are particularly garnering interest and attention from researchers, as they avoid interference from sample autoluminescence and offer highly sensitive chemical analysis and bioluminescent imaging.

[0003] Organic fluorescent small molecules are primarily categorized by their aggregation-induced emission properties into aggregation-induced emission (AIE) and aggregation-quenched fluorescence (ACQ) materials. ACQ materials exhibit strong fluorescence emission in dilute solutions. However, at high concentrations, in the aggregated state or in the solid state, strong intermolecular π-π stacking interactions can lead to energy loss in the excited state, increased nonradiative transitions, and fluorescence quenching. Therefore, ACQ materials have broad applications in bioimaging and fluorescence sensing in dilute solutions. However, their practical applications are limited by their weak or absent fluorescence in the aggregated state. In contrast to ACQ materials, AIE materials exhibit weak fluorescence emission in dilute solutions but exhibit strong fluorescence emission efficiency in the aggregated state at higher concentrations, making them promising for applications in aggregated materials such as thin films and nanoparticles. Dual-state emission (DSE) organic fluorescent small molecules are a new class of materials that exhibit strong fluorescence emission in both dilute solutions and in the aggregated state. Their excellent fluorescence emission properties in solution make them suitable for sensing and bioimaging. Furthermore, their excellent fluorescence emission properties in the solid state offer broad application prospects in flat-panel displays and electronic devices. The development of DSE materials addresses the limitations of ACQ and AIE materials in the field of optical materials and opens up new horizons for the development of new fluorescent materials. By introducing DSE molecules into gels and constructing dynamic gel systems, the material achieves dual fluorescence emission characteristics in both solution and aggregated states. This overcomes the limitation of traditional fluorophores in the preparation of organic small molecule luminescent gels, which suffer from fluorescence quenching due to aggregation, resulting in the inability of fluorescent gels to emit light normally. This provides a new strategy for the development of high-performance fluorescent soft materials. In the preparation of organic small molecule gel factors, imine-based luminescent materials have attracted widespread attention due to their readily available raw materials, low cost, and easy structural modification. However, there are relatively few studies on organic small molecule gel factors with triple-state red light emission based on imine materials. Summary of the Invention

[0004] In response to the problems existing in the prior art, the present invention provides an asymmetric imine gel factor with three-state red light emission, a gel material thereof, and a preparation method and application thereof.

[0005] The present invention is achieved through the following technical solutions: An imine gelator with triple-state red light emission, wherein the gelator is an asymmetric cholesterol-phenoxy-maleonitrile-diethylamino salicylic acid gelator, and its structure is:

[0006] The asymmetric imine gelator exhibits red fluorescence emission in the form of solid powder, solution and gel self-assembled in toluene.

[0007] Another object of the present invention is to provide a method for preparing the triple-state red-light-emitting asymmetric imine gelator, comprising the following steps: S1. 4-diethylamino salicylaldehyde was placed in a round-bottom flask containing anhydrous ethanol, followed by the addition of diaminomaleonitrile and glacial acetic acid, and the reaction was heated to reflux for 5 hours; the reaction mixture was filtered, washed with anhydrous ethanol, and dried to obtain a monomaleonitrile-diethylamino salicylic acid compound; S2. Under nitrogen, 4-hydroxybenzaldehyde was placed in a round-bottom flask containing anhydrous acetonitrile, K2CO3 was added, and the mixture was refluxed for 2 hours. Then, a white cholesterol chloroacetate compound was added and refluxed for another 5 hours. The resulting reaction mixture was washed with water, extracted with a 2% CH3OH-CHCl3 mixture, dried, filtered, and the solvent evaporated to dryness. The mixture was recrystallized to obtain the cholesterol acetate-modified benzaldehyde compound. S3. The monomaleonitrile-diethylamino salicylic acid compound obtained in step S1 is placed in a dichloromethane-anhydrous ethanol mixed solvent, and the cholesterol acetate-modified benzaldehyde and sulfuric acid obtained in step S2 are added. The temperature is raised to reflux and the reaction is reacted for 5-8 hours. The resulting reaction mixture is filtered, washed with anhydrous ethanol, and dried to obtain a cholesterol-phenoxy-maleonitrile-diethylamino salicylic acid gelling factor.

[0008] Furthermore, in step S3, the molar ratio of the monomaleonitrile-diethylamino salicylic compound and the cholesterol acetate-modified benzaldehyde is 1:1, the volume ratio of dichloromethane and anhydrous ethanol in the mixed solvent is 2:3, the amount of the mixed solvent added is limited to 40 mL of the mixed solvent for every 1 mmol of the monomaleonitrile-diethylamino salicylic compound, and the amount of sulfuric acid added is 100 μL of sulfuric acid for every 1 mmol of the cholesterol acetate-modified benzaldehyde.

[0009] The preparation reaction formula of the cholesterol-phenoxy-maleonitrile-diethylamino salicylic acid gel factor is: .

[0010] The third object of the present invention is to provide a method for forming a three-dimensional network gel using the imine gelator.

[0011] Furthermore, a "heating-cooling" gelation method was adopted: 10 mg of imine gel factor was weighed and placed in a series of 2 mL penicillin vials, 0.5 mL of toluene, 1,2-dichloroethane, and chloroform / methanol were added respectively, and heated until the gel factor was completely dissolved. The gel was allowed to stand and cool to room temperature, and three-dimensional network gels with different morphologies were formed after 1 minute.

[0012] The fourth object of the present invention is to provide the imine gel factor of the triple red light emission in Fe 3+ 、Co 2+ Application of detection.

[0013] The specific manifestations are as follows: the gel formed by the asymmetric imine gel factor in toluene has red fluorescence emission properties. After the addition of Fe³⁺ and Co²⁺, its red fluorescence emission properties decrease and the gel color shows a colorimetric response from red to black.

[0014] The fifth object of the present invention is to provide the imine gel factor of the triple red light emission in Cu 2+ Applications of ion detection.

[0015] Furthermore, the three-state red light emitting imine gel factor has a great effect on Cu 2+ It exhibits intuitive color and fluorescence "on-off" signal detection functions, as shown below: Cu is added to the three-dimensional network gel soft material system formed by the imine gel factor of the triple red light emission 2+ After that, the red fluorescence emission of the system was quenched, the gel color showed a colorimetric response from red to black, and at the same time, it showed a triple signal response from gel to sol phase transition, which gave the cholesterol-phenoxy-maleonitrile-diethylamino salicylic acid gel system a fast, sensitive, multi-signal analysis and monitoring of Cu 2+ Function; In the fluorescence emission spectrum of the triple red light emitting imine gel factor solution, when no metal ions are added, the imine gel factor has a strong maximum fluorescence emission near 630 nm. 2+ After the addition of other metal ions, the maximum fluorescence emission of the compound did not change significantly, giving the cholesterol-phenoxy-maleonitrile-diethylamino salicylic gel factor a fluorescence "on-off" detection of Cu 2+ potential.

[0016] The sixth object of the present invention is to provide the imine gel factor of the triple red light emission in Pb 2+ Applications of ion detection.

[0017] Furthermore, the triple red light emitting imine gel factor-Cu 2+ The system has a certain red fluorescence emission, Pb 2+ After addition, the fluorescence of the binary system is completely quenched. After the addition of other metal ions, the fluorescence emission of the binary system remains basically unchanged. 2+ System for Pb 2+ It has a clear fluorescence "on-off" detection response.

[0018] Compared with the prior art, the present invention has the following technical effects: the cholesterol-phenoxy-maleonitrile-diethylamino salicylic gel factor can form three-dimensional nano-network gels with different morphologies in 1,2-dichloroethane, toluene, and chloroform / methanol; the gel and solution states formed in solid powder and toluene all exhibit red fluorescence emission; the red light emitting gel formed in toluene encounters Fe 3+ 、Co 2+ When the red light emission is quenched, the gel color changes from red to black; Cu 2+ The presence of Cu in the solution not only changes the color of the gel from red to black and weakens the fluorescence emission, but also induces the gel to transform into a sol phase. 2+ The red light emission weakened, and the dual state of gel and solution was achieved. 2+ Fast and sensitive detection, especially for Cu 2+ The dual-state detection response is fast, convenient, and sensitive, and has high application value; the cholesterol-phenoxy-maleonitrile-diethylamino salicylic gel factor assembly gel process provided by the present invention has the advantages of mild synthesis conditions and simple preparation, creating favorable conditions for its promotion and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is the NMR spectrum of the triple-state red-emitting imine gel factor.

[0020] Figure 2 SEM image of the gel formed by the triple-state red-light-emitting imine gel factor in 1,2-dichloroethane.

[0021] Figure 3 SEM image of the gel formed by the triple-state red-emitting imine gel factor in chloroform / methanol.

[0022] Figure 4 This is the SEM image of the gel formed by the triple-state red light-emitting imine gel factor in toluene.

[0023] Figure 5 These are red light emission photos of the three-state red light emitting imine gel factor in solid, gel and solution states under ultraviolet light.

[0024] Figure 6 These are photos of the gel formed by the triple-state red-light-emitting imine gel factor after adding different metal ions under sunlight and ultraviolet light.

[0025] Figure 7 The fluorescence detection performance of the imine gel factor with triple red light emission in solution state for different metal ions.

[0026] Figure 8 The red emission of the imine gel factor in the three-state solution is affected by different concentrations of Cu 2+ Fluorescence detection performance.

[0027] Figure 9 The imine gel factor solution state Cu is a triple red light emitting 2+ Compete with other metal ions for performance. DETAILED DESCRIPTION

[0028] The present invention discloses an asymmetric cholesterol-phenoxy-maleonitrile-diethylamino salicylic acid gel factor with triple red light emission, and its molecular structure is:

[0029] It can be prepared by a three-step polymerization reaction using diaminomaleonitrile, 4-diethylamino salicylaldehyde, cholesterol chloroacetate and p-hydroxybenzaldehyde as reaction raw materials. The synthetic reaction formula is: .

[0030] Example 1 Preparation of Compound A: Place 1 mmol of 4-diethylaminosalicylaldehyde in a round-bottom flask containing 20 mL of anhydrous ethanol, followed by 1 mmol of diaminomaleonitrile and 100 μL of glacial acetic acid. Heat to reflux and react for 5 hours. Filter the resulting reaction mixture, wash with anhydrous ethanol, and dry to obtain a monomaleonitrile-diethylaminosalicylaldehyde compound. Under N2 protection, 1 mmol of 4-hydroxybenzaldehyde was placed in a round-bottom flask containing 20 mL of anhydrous acetonitrile, 2 mmol of K2CO3 was added, and the mixture was refluxed for 2 h. Then, 1 mmol of cholesterol chloroacetate was added and the reaction was continued under reflux for 5 h. The resulting mixture was washed with water, extracted with a 2% CH3OH-CHCl3 mixture, dried, filtered, and the solvent was evaporated to dryness. The mixture was recrystallized to obtain a cholesterol acetate-modified benzaldehyde compound. 1 mmol of monomaleonitrile-diethylamino salicylate was placed in 40 mL of a 2:3 dichloromethane-ethanol mixed solvent. 1 mmol of a cholesterol acetate-modified benzaldehyde compound and 100 μL of sulfuric acid were added, and the mixture was heated to reflux for 5 hours. The reaction mixture was filtered, washed with anhydrous ethanol, and dried to obtain 587 mg of a pink-purple compound A with a yield of 72%.

[0031] Example 2 Place 1 mmol of 4-diethylamino salicylaldehyde in a round-bottom flask containing 20 mL of anhydrous ethanol, followed by 1 mmol of diaminomaleonitrile and 100 μL of glacial acetic acid. Heat to reflux and react for 5 hours. Filter the resulting reaction mixture, wash with anhydrous ethanol, and dry to obtain a monomaleonitrile-diethylamino salicylaldehyde compound. Under N2 protection, 1 mmol of 4-hydroxybenzaldehyde was placed in a round-bottom flask containing 20 mL of anhydrous acetonitrile, 2 mmol of K2CO3 was added, and the mixture was refluxed for 2 h. Then, 1 mmol of cholesterol chloroacetate was added and the reaction was continued under reflux for 5 h. The resulting mixture was washed with water, extracted with a 2% CH3OH-CHCl3 mixture, dried, filtered, and the solvent was evaporated to dryness. The mixture was recrystallized to obtain a cholesterol acetate-modified benzaldehyde compound. 1 mmol of monomaleonitrile-diethylamino salicylate was placed in 40 mL of a 2:3 dichloromethane-ethanol mixed solvent. 1 mmol of a cholesterol acetate-modified benzaldehyde compound and 100 μL of sulfuric acid were added, and the mixture was heated to reflux for 8 hours. The reaction mixture was filtered, washed with anhydrous ethanol, and dried to obtain 611 mg of a pink-purple compound B with a yield of 75%.

[0032] 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, CDCl3) δ 12.30 (s, 1H), 8.53 (d, J = 9.9 Hz, 1H), 8.38 (s, 1H), 7.81 (d, J = 8.8 Hz, 2H), 7.23 (t, J = 8.4 Hz, 1H), 6.99 (d, J= 8.8 Hz, 2H), 6.38 (d, J = 10.3 Hz, 2H), 5.41 (d, J = 4.0 Hz, 1H), 5.13 (s,2H), 4.78 (d, J = 8.7 Hz, 1H), 4.69 (s, 2H), 3.46 (dd, J = 7.1, 2.1 Hz, 4H),2.37 (d, J = 8.0 Hz, 2H), 2.02 (s, 2H), 1.89 (s, 4H), 1.60 (s, 6H), 1.52 (s,4H), 1.35 (s, 3H), 1.26 (d, J = 2.1 Hz, 6H), 1.14 (s, 6H), 1.04 (s, 4H), 0.94(d, J = 6.5 Hz, 3H), 0.89 (dd, J = 6.6, 1.7 Hz, 6H), 0.70 (s, 3H). Elemental analysis results of compound A / B were: Measured: C, 75.24; H, 8.30; N, 8.60. Theoretical: C, 75.38; H, 8.49; N, 8.76; indicating that the theoretical values ​​of the gelation factors of compounds A / B are basically consistent with those of cholesterol-phenoxy-maleonitrile-diethylamino salicylic acid. This confirms that the molecular structures of compounds A and B are: That is, cholesterol-phenoxy-maleonitrile-diethylamino salicylic acid gel factor.

[0033] Example 3 Gel-forming properties of the cholesterol-phenoxy-maleonitrile-diethylamino salicylic gelator: The gel formation process was tested using both the "heating-cooling" and "test tube inversion" methods. 10 mg of the gelator was added to separate vials of penicillin, followed by 0.5 mL of various organic solvents, such as methanol, ethanol, toluene, 1,2-dichloroethane, acetonitrile, DMF, DMSO, chloroform-methanol (3:2, v:v), and dichloromethane-methanol (3:2, v:v). After heating to dissolve, the mixture was allowed to cool slowly. After 1 minute, the cholesterol-phenoxy-maleonitrile-diethylamino salicylic gelator formed stable gels in solvents such as 1,2-dichloroethane, toluene, and chloroform:methanol (3:2 v / v). Furthermore, in order to explore the morphology of the formed gel, the obtained cholesterol-phenyl-maleonitrile-diethylamino salicylic gel was prepared into a dry gel: the cholesterol-phenoxy-maleonitrile-diethylamino salicylic gel factor was heated in toluene / 1,2-dichloroethane / chloroform: methanol (3 / 2 v / v) until it dissolved to form a uniform solution. The solution was drawn up while hot and evenly spread on a small glass slide of an electron microscope to form a gel at room temperature. The solution was vacuumed at low temperature until the solution evaporated. The prepared dry gel was placed under a scanning electron microscope to observe its morphology and structure, and the following morphology gel was obtained: In 1,2-dichloroethane, the cholesterol-phenoxy-maleonitrile-diethylamino salicylic gel factor self-assembled to form a fiber network structure with a diameter of about 0.3 μm. Its dense interpenetration and microporous characteristics can efficiently capture solvent molecules ( Figure 2 When the solvent was switched to chloroform:methanol (3:2, v / v), the solvent polarity increased, causing the compound's morphology to transform into a flat ribbon structure (1-2 μm in diameter) ( Figure 3 Based on the rigid planar structure of toluene, the cholesterol-phenoxy-maleonitrile-diethylamino salicylic gel factor is driven to form short rod-shaped nanounits (diameter 0.5 μm, length 5-10 μm) through the π-π stacking effect. For specific results, see Figure 4 , indicating that the solvent polarity and its spatial matching can regulate the strength of the interaction force and stacking pattern between gel factors, thereby assembling organic small molecule gels of different dimensions.

[0034] Example 4 The triple-state fluorescence emission characteristics of cholesterol-phenoxy-maleonitrile-diethylamino salicylic acid gel factor: The gel factor was dissolved in DMF solvent to prepare a concentration of 2 x10 -5 M concentration solution; 10 mg of the gel factor was placed in a penicillin vial, 0.5 mL of toluene was added, and the mixture was heated to dissolve and then allowed to cool slowly. A stable gel was formed after 1 minute; 5 mg of cholesterol-phenoxy-maleonitrile-diethylamino salicylic acid gel factor was placed side by side with the above solution and gel; under 365 nm ultraviolet light excitation, the solid powder, solution and self-assembled gel state all showed red fluorescence emission ( Figure 5 ), indicating that the gel factor has good triple-state red light emission characteristics.

[0035] Example 5 The performance of the gel formed by cholesterol-phenoxy-maleonitrile-diethylamino salicylic acid gel factor for metal ion detection was studied by adding 1 equivalent of Fe to the gel formed by self-assembly of the gel factor in toluene. 3+ 、Co 2+ and Cu 2+ After the ionization, the gel color changes from red to black, especially Cu 2+ After addition, the gel was induced to transform into sol phase; under 365 nm ultraviolet light, Fe 3+ 、Co 2+ and Cu 2+ After the addition of Na ions, the red fluorescence of the gel system is completely quenched, while the remaining Na + , K + 、Li + Mg 2+ , Ca 2+ , Pb 2+ Cr 3+ 、Al 3+ 、Cd 2+ 、Mn 2+ 、Ni 2+ , Pb 2+ 、Zn 2+ No obvious optical and physical changes occurred after the addition of metal ions ( Figure 6 ). These results indicate that cholesterol-phenoxy-maleonitrile-diethylamino salicylic acid gel factor toluene gel not only has a positive effect on Fe 3+ 、Co 2+ It has colorimetric signal and fluorescence emission dual detection response; 2+ It has colorimetric signal change, red light emission quenching, and gel-sol phase transition response to achieve Cu 2+ Two-state, three-signal detection potential.

[0036] Example 6 Detection performance of cholesterol-phenoxy-maleonitrile-diethylamino salicylic acid gel factor solution for metal ions: in 10% H2O-DMF mixed solvent, the concentration was 1×10 -5 mol / L cholesterol-phenoxy-maleonitrile-diethylamino salicylic gel factor has a maximum fluorescence emission at 630 nm; 10 times the molar equivalent of Cu 2+ After addition, the maximum fluorescence emission peak position of the gel factor did not change, but its fluorescence emission intensity was greatly reduced, by 60%; other metal ions such as Li + 、Na + , K +、Ba 2 + , Ca 2+ Mg 2+ 、Zn 2+ 、Co 2+ , Pb 2+ 、Cd 2+ 、Mn 2+ 、Ni 2+ 、Al 3+ 、Fe 3+ After addition, the fluorescence emission of the gel factor showed almost no significant change ( Figure 7 ). These results indicate that cholesterol-phenoxy-maleonitrile-diethylamino salicylic acid gel factor has an effect on Cu 2+ The ions showed obvious fluorescence "on-off" monitoring response.

[0037] Example 7 Effect of cholesterol-phenoxy-maleonitrile-diethylamino salicylic acid gel factor on the effect of different concentrations of Cu 2+ Optical detection function: In 10% H2O-DMF mixed solvent, the concentration is 1×10 -5 mol / L cholesterol-phenoxy-maleonitrile-diethylamino salicylic gel factor was added with different concentrations of Cu 2+ Fluorescence emission spectrum performance is as follows: With the Cu 2+ When the concentration increases from 0 to 10 times the molar equivalent, the maximum fluorescence emission of the compound near 630 nm gradually decreases; then continue to increase Cu 2+ The fluorescence emission spectrum remains essentially unchanged even at a concentration of 20 times the molar equivalent. For specific results, see Figure 8 , indicating that cholesterol-phenoxy-maleonitrile-diethylamino salicylic acid gel factor has an effect on Cu 2+ It has the potential for sensitive fluorescence "off-on" signal detection.

[0038] Example 8 Cu in cholesterol-phenoxy-maleonitrile-diethylamino salicylic acid gel factor 2+ Competitive performance with other metal ions: at a concentration of 1×10 -5 mol / L cholesterol-phenoxy-maleonitrile-diethylamino salicylic gel factor 10% H2O-DMF mixed solvent was added with 10 times the molar equivalent of Cu 2+ and other different metal ions. The fluorescence emission spectrum study of the mixed system showed that when 10 times the molar equivalent of Cu was added to the cholesterol-phenoxy-maleonitrile-diethylamino salicylic acid gel factor, the 2+ After that, the maximum fluorescence emission intensity at 630 nm decreased by 60%; when Li + 、Na + , K +、Ba 2+ , Ca 2+ Mg 2+ 、Zn 2+ 、Co 2+ 、Cd 2+ 、Mn 2+ 、Ni 2+ 、Al 3+ 、Fe 3+ Metal ions such as Cu 2+ After adding cholesterol-phenoxy-maleonitrile-diethylamino salicylic gel factor at the same time, the fluorescence emission of the three mixed system is similar to that of cholesterol-phenoxy-maleonitrile-diethylamino salicylic gel factor-Cu 2+ The fluorescence of the system is similar; while Pb 2+ After addition, cholesterol-phenoxy-maleonitrile-diethylamino salicylic acid gel factor-Cu 2+ The fluorescence emission of the system is completely quenched. For detailed results, see Figure 9 , indicating that cholesterol-phenoxy-maleonitrile-diethylamino salicylic gel factor not only 2+ With good selectivity, it 2+ The mixed binary system has a great influence on the Pb 2+ It has a clear fluorescence "on-off" detection response.

[0039] In summary, the cholesterol-phenoxy-maleonitrile-diethylamino salicylic gel factor can form different three-dimensional network gels in 1,2-dichloroethane, chloroform-methanol (3:2), and toluene solvents; and it exhibits red fluorescence emission in solid, gel and solution states; the gel formed in toluene has a strong affinity for Fe 3+ 、Co 2+ It has intuitive colorimetric change and fluorescence "on-off" dual signal detection response, and is sensitive to Cu 2 It has three signal responses: colorimetric signal, fluorescence "on-off" and gel to sol state conversion; the gel factor solution state is sensitive to Cu 2 It has fluorescence "on-off" detection performance; 2+ The formed binary system has a great influence on the Pb 2+ It has a sensitive red fluorescence emission "on-off" detection signal, which realizes the single factor Fe 3+ 、Co 2+ 、Cu 2 , Pb 2+ Four ion detection is fast, intuitive and accurate.

Claims

1. An imine gelator with triple-state red light emission, characterized in that: The imine gel factor is an asymmetric cholesterol-phenoxy-maleonitrile-diethylamino salicylic acid gel factor, and its structure is: 。 2. A method for preparing the imine gelator according to claim 1, characterized in that: The steps include: S1. 4-diethylamino salicylaldehyde was placed in a round-bottom flask containing anhydrous ethanol, followed by the addition of diaminomaleonitrile and glacial acetic acid, and the reaction was heated to reflux for 5 hours; the reaction mixture was filtered, washed with anhydrous ethanol, and dried to obtain a monomaleonitrile-diethylamino salicylic acid compound; S2. Under nitrogen, 4-hydroxybenzaldehyde was placed in a round-bottom flask containing anhydrous acetonitrile, K2CO3 was added, and the mixture was refluxed for 2 hours. Then, a white cholesterol chloroacetate compound was added and refluxed for another 5 hours. The resulting reaction mixture was washed with water, extracted with a 2% CH3OH-CHCl3 mixture, dried, filtered, and the solvent evaporated to dryness. The mixture was recrystallized to obtain the cholesterol acetate-modified benzaldehyde compound. S3. The monomaleonitrile-diethylamino salicylic acid compound obtained in step S1 is placed in a dichloromethane-anhydrous ethanol mixed solvent, and the cholesterol acetate-modified benzaldehyde and sulfuric acid obtained in step S2 are added. The temperature is raised to reflux and the reaction is reacted for 5-8 hours. The resulting reaction mixture is filtered, washed with anhydrous ethanol, and dried to obtain a cholesterol-phenoxy-maleonitrile-diethylamino salicylic acid gelling factor.

3. The method for preparing the imine gelator according to claim 2, wherein: In step S3, the molar ratio of the monomaleonitrile-diethylamino salicylic compound and the cholesterol acetate-modified benzaldehyde is 1:1, the volume ratio of dichloromethane and anhydrous ethanol in the mixed solvent is 2:3, the amount of the mixed solvent added is limited to 40 mL of the mixed solvent per 1 mmol of the monomaleonitrile-diethylamino salicylic compound, and the amount of sulfuric acid added is 100 μL of sulfuric acid per 1 mmol of the cholesterol acetate-modified benzaldehyde.

4. The gelling material performance of the imine gelator according to claim 1, characterized in that: 10 mg of imine gel factor was placed in a series of small reagent bottles, and 0.5 mL of toluene, 1,2-dichloroethane, chloroform and methanol (3:2) solvents were added respectively. After heating to dissolve, the mixture was allowed to stand and cooled. After 1 minute, the gel materials self-assembled into short rod-shaped, fiber network and flat ribbon-shaped three-dimensional network structure gel materials.

5. The triple-state red light emission characteristic of the imine gelator according to claim 1, characterized in that: The imine gel factor exhibits red fluorescence emission properties in the form of solid powder, DMF solution and gel formed in toluene.

6. An imine gelling factor as claimed in claim 1 forms a gel in toluene 3+ 、Co 2+ The application in detection is characterized by: The gel formed by the imine gel factor in toluene has red fluorescence emission properties. 3+ 、Co 2+ After that, the color of the gel changes from red to black, and the red fluorescence emission performance decreases. 3+ 、Co 2+ It has fast and intuitive detection performance.

7. An imine gel factor as claimed in claim 1 in Cu 2+ Application in detection.

8. imine gel factor according to claim 7 in Cu 2+ The application in detection is characterized by: The imine gelator forms a red fluorescence emitting gel in toluene, Cu 2+ After addition, the red fluorescence emission of the gel was quenched, the gel color changed from red to black, and the gel became a sol. 2+ It has triple intuitive signal detection performance: colorimetric change, fluorescence "on-off", and gel-to-sol transformation.

9. The imine gel factor according to claim 7 in Cu 2+ The application in detection is characterized by: The gel factor has a maximum fluorescence emission near 630 nm in a 10% H2O-DMF mixed solvent. 2+ After that, the maximum fluorescence emission intensity decreased by 60%, which gave the imine gel factor the ability to inhibit Cu 2+ Fluorescence "on-off" signal detection performance.

10. An imine gel factor as claimed in claim 1 in Pb 2+ The application in detection is characterized by: The imine gel factor-Cu 2+ The binary system has a certain red fluorescence emission, Pb 2+ After the addition of metal ions, the fluorescence of the binary system is completely quenched. After the addition of other metal ions, the fluorescence of the binary system remains basically unchanged, making the imine gel factor-Cu 2+ Binary system for Pb 2+ It has obvious fluorescence "on-off" detection performance.

Images