Cucurbituril[7]-cyclodextrin cascade assembly supramolecular system for specifically detecting trivalent gold and preparation method thereof
By assembling a supramolecular system using cucurbituril[7]-cyclodextrin cascades, the problem of large error in gold ion detection was solved, and Au3+ detection with high selectivity and low cost was achieved. The fluorescence intensity and lifetime were significantly improved, making it suitable for specific detection of Au3+ in aqueous and solid environments.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- QUFU NORMAL UNIV
- Filing Date
- 2024-01-08
- Publication Date
- 2026-07-24
Smart Images
Figure CN117866620B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a novel cascaded confined luminescent pseudorotaxane complex for the specific recognition of gold ions. Background Technology
[0002] Gold is a precious metal with a wide range of uses. In the chemical industry, its unique properties and stability make it an indispensable component in many chemical products. Due to its excellent electrical conductivity and chemical stability, gold is also widely used in the manufacture of electronic devices. However, gold is non-biodegradable and accumulates in the environment. Gold can bind tightly to biomolecules such as enzymes and DNA, posing a toxic risk to humans. Furthermore, intermediates and precursors from gold processing, such as Au(I) and Au(III) compounds, are highly reactive and potentially harmful to humans. Trivalent gold (such as gold chloride (AuCl3)) can damage the liver, kidneys, and peripheral nervous system.
[0003] Currently, there are many methods for detecting gold content, including titration, spectrophotometry, electrochemical methods, atomic absorption spectrometry, and fluorescence spectrometry. Titration is based on the fact that gold is usually in a trivalent state, and a reduction reaction is used to convert the trivalent gold ions to a monovalent or zero-valent state. 1) Titration to zero valence: Hydroquinone is usually used as the titrant, and 3',3-dimethylbenzidine or benzidine or their derivatives are used as indicators. 2) Titration to monovalent state: The most representative method is iodometric titration: AuCl4 - +3KI=AuI+I2+3KCl+Cl - The disadvantage of titration is that the determination of the titration endpoint often involves subjective factors of the analyst, which can easily lead to errors and affect the accuracy of the detection. Electrochemical analysis can only detect trace amounts of gold, making it unsuitable for the determination of trace gold ions. Among these methods, fluorescence spectroscopy for gold content detection has attracted widespread attention due to its advantages such as convenience, speed, and low detection limits. Therefore, exploring a low-cost, highly selective method for detecting gold ions that can be performed in an aqueous phase and is suitable for environmental use has become an important research goal. Thus, developing a method specifically for detecting Au in the environment is crucial. 3+ The supramolecular system has great development potential.
[0004] In recent years, pseudorotaxanes containing two or more components have received widespread attention as a typical representative of mechanically interlocked molecules. They are bound by non-covalent forces such as hydrogen bonds, hydrophobic interactions, π-π stacking, ionic dipole interactions, electrostatic interactions, host-guest interactions, and coordination bonds. Pseudorotaxanes contain a linear axis and two or more macrocycles. As a precursor of multifunctional supramolecular materials such as rotaxanes and cyclohexanes, pseudorotaxanes have inherent dynamic potential applications. The most commonly used macrocycle for preparing pseudorotaxanes is cucurbituril[n] (CB[n]), which is composed of different numbers of glycoure units and forms inclusion complexes with organic cationic guests (i.e., ammonium, pyridine, and imidazole cations, etc.), exhibiting high selectivity and bonding ability in aqueous solutions. For example, CB[8] can simultaneously bind two different types of fluorescent guest molecules within its cavity to form a ternary complex. However, most cucurbituril[n] (CB[6] and CB[7], etc.) cavities are too small to accommodate two or more guests simultaneously. Therefore, it is necessary to develop new host-guest recognition modes in cucurbituril[n] with smaller cavities and stronger binding capacity, but this is also quite difficult. In addition, confining guest molecules within the cavity of cucurbituril[n] can significantly alter the acidity, photostability, chemical and physical properties of the guests. From a structural perspective, cucurbituril[n] provides a rigid environment for the encapsulated fluorescent dye molecules, preventing the aggregation of dyes at high concentrations, and can even generate macrocyclic assembly-induced fluorescence. For example, Ni et al. reported a color-tunable pseudopolyrotaxane that, by using different numbers of CB[8] hosts to encapsulate poly(styrene derivatives), achieved color variations from blue to cyan, white, yellow or green, and gave it a long fluorescence lifetime and high fluorescence quantum yield. Compared with primary assembly, the cascade assembly of amphiphilic macrocyclic compounds can improve the hydrophobic microenvironment of the assemblies. Simultaneously, it can co-assemble with drug molecules, dye molecules, and photoresponsive molecules to form nanofibers, nanoparticles, and nanorods, further promoting the luminescence behavior and delivery of the target substance, and enabling applications in targeted drug delivery, bioimaging, and information anti-counterfeiting. Therefore, designing a novel cascaded assembly confined fluorescent pseudorotaxane complex is urgently needed by engineers and scientists in the fields of imaging and recognition. Summary of the Invention
[0005] Fluorescence analysis is relatively accurate for analyzing the types and contents of metal ions in samples, but it may be affected by some interfering factors during the analysis process. Therefore, the purpose of this invention is to solve the problem that gold ions in the environment are difficult to detect and have large errors. It provides a novel cascaded assembly confined luminescent pseudorotaxane complex - cucurbituril[7]-cyclodextrin cascaded assembly supramolecular system and its preparation method; and uses the prepared supramolecular system for specific detection of Au in the environment. 3+ .
[0006] This invention utilizes 4,4',4”,4”'-((6,7,9,10,12,13,20,21,23,24,26,27-dodecahydrodibenzo[b,n][1,4,7,10,13,16,19,22]octaoxacyclotetracosine-2,3,16,17-tetrayl)tetrakis(benzene-4,1-diyl))tetrakis(1-((2-oxo-2H-chromen-6-yl)methyl)pyridin-1-ium)bromide(G), CB[7], and sulfobutyl-β-cyclodextrin (SBE-β-CD) to construct the first CB[7]-mediated molecular slip and cascade assembly pseudo[5] rotaxane supramolecular complex in aqueous solution. This assembly exhibits Au resistance in aqueous solution and solid PVA membrane. 3+ It exhibits a specific fluorescence quenching effect.
[0007] Based on the host-guest interactions and electrostatic interactions of G, CB[7], and SBE-β-CD, this invention successfully prepared a cascaded assembly fluorescence-enhanced supramolecular complex with green fluorescence and tunable morphology. Due to the strong confinement effect of CB[7], primary assembly increased the fluorescence intensity of G by 53 times, and the fluorescence lifetime significantly increased from 0.65 ns to 3.76 ns. Subsequent secondary assembly with SBE-β-CD further blue-shifted the fluorescence wavelength from 530 nm to 515 nm, increasing the intensity by 9.9 times, but without a significant increase in fluorescence lifetime. It is noteworthy that in… In the middle, Au 3+ and The binding of crown ether groups can serve as an excellent dedicated probe for gold ions, whether in solution or on a solid PVA film.
[0008] The technical solution of the present invention:
[0009] One of the schemes is the preparation method of a macrocyclic mediated supramolecular system of cucurbituril[7]-cyclodextrin cascade assembly for specific detection of trivalent gold.
[0010] The present invention utilizes a co-assembly of a leucomatin-modified dibenzo-24 crown-8 guest (G), CB[7], and sulfobutyl-β-cyclodextrin (SBE-β-CD) to construct the first CB[7]-mediated molecular slip and cascade assembly-confined pseudo[5] rotaxane supramolecular complex in aqueous solution. In the process, when G is encapsulated by CB[7] in a dynamic sliding manner to form pseudo[5] rotaxane, At the same time, macrocyclic confinement not only effectively achieved blue shift, increased fluorescence intensity, and increased fluorescence lifetime, but also yielded larger nanoparticles. Larger nanoparticles were formed through electrostatic interactions and the cascade assembly of negatively charged SBE-β-CD. It further improved fluorescence emission, but the increase in fluorescence lifetime was minimal. The chemical structural formula of its building blocks is as follows:
[0011]
[0012] Macrocyclic-mediated specific detection The preparation method of the system includes the following steps:
[0013] Step 1, Preparation of G,
[0014] The synthesis route is as follows:
[0015]
[0016] The preparation method is as follows:
[0017] Step 1.1: Synthesize compound 1 according to the literature.
[0018] Step 1.2: Compound 1, (4-(pyridin-4-yl)phenyl)boronic acid, K2CO3, THF, and H2O were added to a container in a molar volume ratio of 1:5:10:40:20, and degassed by a freeze-thaw cycle. Under argon protection, 0.1% Pd(PPh3)4 was added, and the mixture was refluxed overnight to remove the organic solvent. Then, 60% CHCl3 was added, and the mixture was washed with H2O. The organic phase was collected, dried over anhydrous Na2SO4, and filtered. After removing CHCl3, the sample was purified by column chromatography to obtain the desired compound 2.
[0019] Step 1.3: Add compound 2, compound 3 and DMF to a container at a molar volume ratio of 1:60:100, react overnight under reflux (100°C), then cool the reaction mixture, add excess acetone to the solution, filter the precipitate, wash with petroleum ether and acetone to obtain yellow solid G.
[0020] Step 2, Preparation of 1-((2-oxo-2H-chromen-6-yl)methyl)-4-phenylpyridin-1-iumbromide1-(G1),
[0021] The synthesis route is as follows:
[0022]
[0023] Compounds 3 and 4-phenylpyridine were added to dry MeCN in a molar volume ratio of 1:10:50, and the mixture was stirred at reflux (85°C) for 60–72 h. The reaction mixture was then cooled, and excess diethyl ether was added to the solution. The precipitate was filtered and washed with diethyl ether to give a white solid, G1.
[0024] Step 3: Macrocyclic-mediated specific detection of Au3+ Preparation of the system
[0025] The first CB[7]-mediated molecular slip and cascade assembly-confined pseudo[5] rotaxane supramolecular complex was constructed in aqueous solution by co-assembly of G, CB[7] and sulfobutyl-β-cyclodextrin (SBE-β-CD). The method is as follows:
[0026] Step 3.1: Add 4 equivalents of cucurbitaureine [7] to G obtained in step 1, and obtain a binary supramolecular system by simple mechanical stirring.
[0027] Step 3.2: After forming the binary supramolecular system, SBE-β-CD is further added to the solution to form a ternary supramolecular system.
[0028] The molar ratio of G, CB[7] and sulfobutyl-β-cyclodextrin (SBE-β-CD) is 1:6:0.6.
[0029] Option Two: Macrocyclic-mediated Specific Detection Application of the system.
[0030] When in Add Tb to the solution 3+ Eu 3+ Pb 2+ Al 3+ K + Ca 2+ Mg 2+ Cs + Ag + Ni + Cu 2+ 、Rb + Li + Hg 2+ and Co 2+ When different metal cations were used, the fluorescence intensity exhibited a slight quenching effect (3.7%-25.4%). However, Na... + This promoted a slight increase in fluorescence. Au was dropped onto a PVA film containing a ternary assembled supramolecular system. 3+ Or use Au 3+ When used as ink to write letters or characters (such as "NK"), The green fluorescence completely disappeared, revealing clear black dots and written letters or characters. Clearly, It can be used as a probe to selectively detect Au in water and solid PVA membranes. 3+ .
[0031] Advantages and beneficial effects of the present invention:
[0032] Based on G, CB[7], and SBE-β-CD, this invention successfully prepared a morphology-tunable cascade assembly-enhanced supramolecular assembly system with green fluorescence through host-guest interactions and electrostatic interactions. Based on the confinement effect of CB[7], primary assembly enhanced the fluorescence of G by 53 times, significantly increasing the fluorescence lifetime from 0.65 ns to 3.76 ns. Subsequent secondary assembly with SBE-β-CD further blue-shifted the fluorescence from 530 nm to 515 nm, increasing the intensity by 9.9 times, and expanding the topological microscale through multivalent interactions, but without a significant increase in fluorescence lifetime. Furthermore, through… Au 3+ The combination with crown ether groups forms It can be used as an excellent source of Au in both solution and solid PVA films. 3+ Specialized probe. Attached Figure Description
[0033] Figure 1 This is the synthesis route for G.
[0034] Figure 2 This is the 1H NMR spectrum of compound 2.
[0035] Figure 3 This is the carbon NMR spectrum of compound 2.
[0036] Figure 4 The image shows the hydrogen NMR spectrum of G.
[0037] Figure 5 The image shows the carbon NMR spectrum of G.
[0038] Figure 6 The synthetic route for 1-((2-oxo-2H-chromen-6-yl)methyl)-4-phenylpyridin-1-ium bromide (G1) is given.
[0039] Figure 7 This is the hydrogen NMR spectrum of G1.
[0040] Figure 8 This is the carbon NMR spectrum of G1.
[0041] Figure 9 For G11 H- 1 H COSY NMR spectrum.
[0042] Figure 10 The figures show (a) the UV absorption spectrum and (b) the fluorescence emission spectrum of G after the addition of CB[7] at 25 °C. The insets are: G (left) and (Right) Image at 365nm.
[0043] Figure 11 The Job plots for G and CB[7] at 315 nm are shown.
[0044] Figure 12 The Job plots for G1 and CB[7] at 315 nm are shown.
[0045] Figure 13 for Two-dimensional ROESY spectrum in D2O.
[0046] Figure 14 The 1H NMR spectra of G2 with 0 equivalent (Ⅰ) and 1.5 equivalent (Ⅱ)CB[7].
[0047] Figure 15 The NMR spectra of G with 0 equivalent (Ⅰ), 1.0 equivalent (Ⅱ), 4.0 equivalent (Ⅲ) and 6.0 equivalent (Ⅳ) and CB[7] are shown.
[0048] Figure 16 for Two-dimensional ROESY spectrum of D2O.
[0049] Figure 17 (a) The 1H NMR spectra of G1 at 0 equivalent (Ⅰ), 0.5 equivalent (Ⅱ), 1.0 equivalent (Ⅲ) and 1.5 equivalent (Ⅳ) CB[7]; (b) The NMR spectra of G. 1 H- 1 H COSY spectrum; (c) Nonlinear least squares fitting of G1 absorbance intensity at 300 nm as a function of CB[7] concentration; (d) G at 560 nm, At 530nm, At 515nm, At 515nm, Fluorescence lifetime at 515 nm.
[0050] Figure 18 For G, and Zeta potential.
[0051] Figure 19 After adding (a) SC4A12 and (b) SC4A8 to water at 25°C The fluorescence emission spectrum.
[0052] Figure 20 The fluorescence emission spectrum of G after adding SBE-β-CD to water at 25℃ is shown.
[0053] Figure 21 For (a) pseudo[5] rotaxane after adding SBE-β-CD to water at 25°C The fluorescence emission spectrum. Illustration: (left) and (Right) Image at 365nm; (b) and Transmittance in aqueous solution and the corresponding Tyndall effect. Illustration: (c) and High-resolution transmission electron microscopy (HR-TEM) images; (d) and Dynamic light scattering analysis diagram.
[0054] Figure 22 for Fluorescence emission spectra after the addition of different metal cations.
[0055] Figure 23 To add Au to water at 25°C 3+ back The fluorescence emission spectrum.
[0056] Figure 24 To add Au to water at 25°C 3+ back The fluorescence emission spectrum.
[0057] Figure 25 (a) The fluorescence emission spectrum of G1 after adding CB[7] to water at 25°C; (b) The fluorescence emission spectrum of G1 after adding SBE-β-CD. The fluorescence emission spectrum.
[0058] Figure 26 For G and Au at 560nm 3+ Fluorescence spectrum in water.
[0059] Figure 27 For (a) (a) Fluorescence quenching efficiency of metal cations in water at 515 nm; (b) In Au 3+ Existence Photographs of the solution and the luminescent film.
[0060] Figure 28 The cascade assembly mechanism of G, CB[7] and SBE-β-CD and Au 3+ Schematic diagram of the detection principle. Detailed Implementation
[0061] Example 1:
[0062] A macrocyclic-mediated specific detection of Au 3+ The system, the system is
[0063] The system described in this invention In the process, when G is encapsulated by the CB[7] host molecule to form pseudo[5] rotaxane At this time, macrocyclic confinement not only effectively achieved blue shift and improved fluorescence intensity, but also increased fluorescence lifetime, and yielded larger nanoparticles. Larger nanoparticles were formed by the cascade assembly of negatively charged SBE-β-CD. The chemical structural formulas of its building blocks are as follows:
[0064]
[0065] I. Macrocyclic-mediated specific detection of Au 3+ of Preparation of the system
[0066] Includes the following steps:
[0067] (1) Preparation of G, the synthetic route is as follows:
[0068]
[0069] The preparation method is as follows:
[0070] Compound 1 was synthesized according to the literature.
[0071] Compound 1 (1.0 mmol), (4-(pyridin-4-yl)phenyl)boronic acid (5 mmol), K₂CO₃ (10.0 mmol), THF (40.0 mL), and H₂O (20.0 mL) were added to a container and degassed by a freeze-thaw cycle. Then, 0.1 mmol of Pd(PPh₃)₄ was added under argon protection. The mixture was refluxed overnight at 100 °C. After removing the organic solvent under vacuum, CHCl₃ (60.0 mL) was added, and the mixture was washed with H₂O. The organic layer was collected, dried over anhydrous Na₂SO₄, and filtered. After removing CHCl₃, the filter cake was purified by column chromatography to obtain the desired compound 2.
[0072] Compound 2 (0.01 mmol), compound 3 (0.6 mmol), and DMF (10.0 ml) were added to a container and reacted overnight at 100 °C. The reaction mixture was then cooled, and excess acetone was added to the solution. The precipitate was filtered and washed with petroleum ether and acetone to give a yellow solid G.
[0073] (2) Ternary supramolecular system Preparation
[0074] Four equivalents of cucurbituril[7] were added to G obtained in step 1, and the binary supramolecular system was obtained by simple mechanical stirring. After forming a binary supramolecular system, adding 0.4 equivalents of SBE-β-CD to the solution further forms a ternary supramolecular system.
[0075] Figure 2 This is the 1H NMR spectrum of compound 2. The figure shows that the structure of compound 2 is correct.
[0076] Figure 3 This is the carbon NMR spectrum of compound 2. The figure shows that the structure of compound 2 is correct.
[0077] Figure 4 This is the hydrogen NMR spectrum of G. The figure shows that the structure of G is correct.
[0078] Figure 5 The image shows the carbon NMR spectrum of G, which indicates that the structure of G is correct.
[0079] Comparative Example 1:
[0080] (1) Preparation of 1-((2-oxo-2H-chromen-6-yl)methyl)-4-phenylpyridin-1-ium bromide1(G1), the synthetic route is as follows:
[0081]
[0082] Compound 3 (1.0 mmol) and 4-phenylpyridine (10.0 mmol) were added to dry MeCN (50 mL), and the mixture was stirred at 85 °C for 72 h. The reaction mixture was then cooled, and excess diethyl ether (200 mL) was added to the solution. The precipitate was filtered and washed with diethyl ether to give a white solid G1.
[0083] (2) Referring to the method in step (2) of Example 1, 4 equivalents of cucurbitaureine [7] were added to G1 obtained in the above step, and the binary supramolecular system was obtained after simple mechanical stirring. After forming a binary supramolecular system, adding 2.5 equivalents of SBE-β-CD to the solution allows for the preparation of a reference supramolecular assembly. The ideal ratio of G1, CB[7] and SBE-β-CD is 1:1:1.6.
[0084] II. Au 3+ Detection
[0085] The standard Au in this embodiment 3+ The aqueous solution and the sample solution to be tested are prepared with chloroauric acid (HAuCl4) as solute and water as solvent.
[0086] Four equivalents of cucurbituril[7] were added to G obtained in step 1, and the binary supramolecular system was obtained by simple mechanical stirring. After forming a binary supramolecular system, adding 0.4 equivalents of SBE-β-CD to the solution further forms a ternary supramolecular system. When in Add Tb to the solution 3+ Eu 3+ Pb 2+ Al 3+ K + Ca 2+ Mg 2+ Cs + Ag + Ni + Cu 2+ 、Rb + Li + Hg 2+ and Co 2+ When different metal cations were used, the fluorescence intensity exhibited a slight quenching effect (3.7%–25.4%). However, Na… + This promoted a slight increase in fluorescence. Au was dropped onto a PVA film containing the above ternary assembly. 3+ Or use Au 3+ When writing the letter "NK" with ink The green fluorescence completely disappeared, revealing clear black dots and letters. Clearly, It can be used as a probe to selectively detect Au in water and solid PVA membranes. 3+ Different metal ions were added to a fluorescence spectrophotometer, and the fluorescence spectra are shown in Figure 27.
[0087] Figure 7 This is the hydrogen NMR spectrum of G1. The figure shows that the structure of G1 is correct.
[0088] Figure 8This is the carbon NMR spectrum of G1. The figure shows that the structure of G1 is correct.
[0089] Figure 9 For G1 1 H- 1 H COSY NMR spectrum. The figure shows the assignment of each hydrogen atom in G1.
[0090] Figure 10 The figures show (a) the UV absorption spectrum of G and (b) the fluorescence emission of G after the addition of CB[7] at 25°C. The insets show G (left) and... (Right) Image at 365 nm. The host-guest bonding behavior of CB[7] and G was studied using UV-Vis absorption spectroscopy and fluorescence emission spectroscopy. Meanwhile, the guest molecule G showed a very weak fluorescence signal at 560 nm. With the addition of CB[7], the fluorescence signal gradually increased. Under a 365 nm UV lamp, when 6.0 equivalents of CB[7] were added, the fluorescence intensity began to stabilize and the color turned yellow.
[0091] Figure 11 To obtain the Job plots of G and CB[7] in water based on the absorbance at 315 nm. The Job plots are shown in X CB[7] When the value is 0.2, an inflection point appears, which initially indicates that G and CB[7] are bound together in a 4:1 host-guest ratio.
[0092] Figure 12 Job plots of G1 and CB[7] at 315 nm. Job's analysis showed a 1:1 stoichiometric relationship between G1 and CB[7]. 1 H NMR analysis also confirmed this, that the chemical shift of G1 / CB[7] remained unchanged when 1.0 or more of CB[7] were added.
[0093] Figure 13 for Two-dimensional ROESY spectra in D2O. The figure shows that the coumarin moiety and the pyridine moiety in G1 are not correlated.
[0094] Figure 14 The NMR spectra of G2 with 0 (Ⅰ) and 1.5 (Ⅱ) equivalents of CB[7]. The figure shows that CB[7] is in a dynamic shuttle process on the G1 axis. As expected, another reference guest, 1-((2-oxo-2H-chromen-6-yl)methyl)pyridin-1-ium bromide(G2), also exhibits a similar NMR shift after the addition of CB[7].
[0095] Figure 15The figure shows the 1H NMR spectra of G with 0 (Ⅰ), 1.0 (Ⅱ), 4.0 (Ⅲ) and 6.0 (Ⅳ) equivalents of CB[7]. The figure shows that, as with G1 and G2, the protons in the four side arms of G are in pseudo[5] rotaxane. Significant high-field shifts also occurred in the middle.
[0096] Figure 16 for Two-dimensional ROESY spectra in D2O. The figure shows that G and CB[7] have obvious NOE effects and spatial correlation.
[0097] Figure 17 (a) The NMR spectra of G1 with 0 (Ⅰ), 0.5 (Ⅱ), 1.0 (Ⅲ) and 1.5 (Ⅳ) equivalents of CB[7] are shown. The figures show that all the hydrogens in G1 undergo a high-field shift after interacting with CB[7]. CB[7] is in a dynamic sliding process on the G1 chain. Furthermore, the NMR does not change after adding 1 equivalent or more of CB[7], which also proves the 1:1 bonding ratio between G1 and CB[7]; (b) of 1 H- 1 H COSY 1 The 1H NMR spectrum, as shown in the figure, indicates Each hydrogen atom has a good assignment; (c) The nonlinear least squares fitting of the absorbance intensity of G1 at 300 nm with the concentration of CB[7] yielded a binding constant (Ks) of 8.2 × 10⁻⁶ for CB[7] and G1. 6 M -1 (d)G at 560nm, At 530nm, exist exist At the fluorescence lifetime of 515 nm, the figure shows that as primary and secondary assembly occur, the fluorescence lifetime of the assembled molecules gradually increases compared to the guest molecules.
[0098] Figure 18 Results for Zeta potential and Unlike G and Excessive positive charge on the surface The zeta potential is approximately 6.8 mV, indicating a reduction in the positive charge on the surface of the ternary nanocomposite.
[0099] Figure 19 for Fluorescence emission spectra after the addition of (a)SC4A12 and (b)SC4A8. In the comparative experiment, two other anionic macrocyclic compounds, dodecyl-modified sulfonyl[4]arene (SC4A12) and octadecyl-modified sulfonyl[4]arene (SC4A8), also enhanced the fluorescence intensity by 5.5 times and 9.5 times, respectively, and the fluorescence lifetimes reached 3.08 and 3.17 ns, respectively.
[0100] Figure 20 The fluorescence emission spectrum of G after the addition of SBE-β-CD is shown. In contrast, the direct assembly of G with SBE-β-CD via multivalent electrostatic interactions only produces a relatively weak increase in fluorescence.
[0101] Figure 21 For (a) pseudo[5] rotaxane Fluorescence emission spectrum after addition of SBE-β-CD. (Illustration:) (left) and (Right) Image at 365 nm. The image shows that the luminescence intensity of the solution gradually increases with the addition of SBE-β-CD, reaching its maximum when 0.6 equivalents of SBE-β-CD are added, and the color of the solution changes from yellow to green; (b) and Transmittance in aqueous solution and the corresponding Tyndall effect. Illustration: I II And Ⅲ(G), the figure shows that G and Ⅲ(G) Its small size results in approximately 100% transmittance at 450nm, with no obvious Tyndall effect; Its microscopic size is relatively large, and its transmittance decreases rapidly at 450 nm, exhibiting a significant Tyndall effect; (c) and The high-resolution transmission electron microscope (HR-TEM) image shows and The microstructure of all particles is nanoparticle, and their size gradually increases; (d) and The dynamic light scattering analysis diagram is shown. TEM images reveal that free G exists in the form of spherical nanoparticles with an average diameter of approximately 6.5 nm. The topological morphologies are similar, but the particle sizes are relatively large, at 20.6 nm and 131.9 nm, respectively. Meanwhile, DLS experiments show corresponding hydrodynamic diameters of 9.9, 29.1, and 166.9 nm, all larger than the TEM results.
[0102] Figure 22 for Fluorescence emission spectra of different metal cations added to water at 25°C. (Adding Au) 3+After (0-85eq.), The fluorescence exhibited a good quenching effect, with a quenching efficiency of 93.7%, and could be observed with the naked eye under a 365nm ultraviolet lamp.
[0103] Figure 23 To add Au to water at 25°C 3+ back The fluorescence emission spectrum was obtained. Simultaneously, Au was calculated based on LOD = 3σ / slope. 3+ The limit of detection (LOD) was 5.8 nmol / L, and the following was given: Fluorescence intensity at 515 nm and Au 3+ Linear relationship of concentration.
[0104] Figure 24 To add Au to water at 25°C 3+ back The fluorescence emission spectrum.
[0105] Figure 25 (a) The fluorescence emission spectrum of G1 after adding CB[7] to water at 25℃; (b) The fluorescence emission spectrum of G1 after adding SBE-β-CD to water at 25℃. The fluorescence emission spectrum. When When used as a probe, with Au 3+ With the gradual addition of [a substance], its fluorescence was significantly enhanced.
[0106] Figure 26 Add Au to water at 25°C 3+ back The fluorescence emission spectrum was obtained. Au was measured by fluorescence titration experiments, specifically by the change in fluorescence intensity at 560 nm. 3+ The stoichiometric ratio of the ions to the G complex is 1:2.
[0107] Figure 27 For G and Au at 560nm 3+ Fluorescence spectrum in water. When in Add Tb to the solution 3+ Eu 3+ Pb 2+ Al 3+ K + Ca 2+ Mg 2+ Cs + Ag + Ni + Cu 2+ 、Rb + Li + Hg 2+ and Co 2+When different metal cations are used, the fluorescence intensity exhibits a slight quenching effect (3.7%–25.4%).
[0108] Figure 28 The cascade assembly mechanism of CB[7] and SBE-β-CD and Au 3+ Schematic diagram of the detection process. A multi-level assembly of green fluorescent supramolecular assembly consisting of a macrocyclic confinement activated yellow fluorescent pseudo[5] rotaxane and subsequently assembled with an anionic cyclodextrin derivative sulfobutyl-β-cyclodextrin (SBE-β-CD). G has 4 cationic coumarin arms and can be encapsulated by cucurbituril[7] (CB[7]) in a stoichiometric ratio of 1:4 in a dynamic sliding mode to form pseudo[5] rotaxane. This not only increased the fluorescence intensity of G, but also its fluorescence lifetime. Subsequently, SBE-β-CD was combined with... Co-assembly controls the topological changes of nanoparticles from small to large, further shifting fluorescence from 530nm to 515nm and increasing intensity by 9.9 times.
Claims
1. A method for preparing a macrocyclic-mediated supramolecular system of cucurbituril[7]-cyclodextrin cascade assembly for specific detection of trivalent gold, namely The system was prepared by co-assembling coumarin-modified dibenzo-24 crown-8 guest G, CB[7] and sulfobutyl-β-cyclodextrin SBE-β-CD in aqueous solution to construct a CB[7]-mediated molecular slip and cascade assembly confinement pseudo[5] rotaxane supramolecular complex. The chemical structural formulas of its building units are as follows: The preparation method includes the following steps: Step 1, Preparation of G; The synthetic route is as follows: 2,3,16,17-tetrakis(4-(pyridin-4-yl)phenyl)-6,7,9,10,12,13,20,21,23,24,26,27-dodecylhydrodibenzo[b,n][1,4,7,10,13,16,19,22]octaoxetane, 2,6-(bromomethyl)coumarin, and DMF were added to a container at a molar volume ratio of 1:60:
100. The mixture was refluxed overnight, and then the reaction mixture was cooled. Excess acetone was added to the solution, and the precipitate was filtered and washed with petroleum ether and acetone to give a yellow solid G. Step 2: Macrocyclic-mediated specific detection of Au 3+ of Preparation of the system: By co-assembling G, CB[7] and sulfobutyl-β-cyclodextrin SBE-β-CD, a pseudo[5] rotaxane supramolecular complex mediated by molecular slip and cascade assembly was constructed in aqueous solution.
2. The method for preparing a macrocyclic-mediated, specific detection supramolecular system of trivalent gold cucurbituril [7]-cyclodextrin cascade assembly as described in claim 1, characterized in that, The molar ratio of G, CB[7] and sulfobutyl-β-cyclodextrin SBE-β-CD is 1:6:0.
6.
3. The method for preparing a macrocyclic-mediated, specific detection supramolecular system of trivalent gold cucurbituril [7]-cyclodextrin cascade assembly as described in claim 1, characterized in that, The preparation method of G in step 1 is as follows: Synthesis route: The preparation method is as follows: Step 1.1: Compound 1, (4-(pyridin-4-yl)phenyl)boronic acid, K2CO3, THF and H2O were added to a container in a molar volume ratio of 1:5:10:40:
20. The mixture was degassed by a freeze-thaw cycle. Then, under an argon atmosphere, 0.1% Pd(PPh3)4 was added as a catalyst in a molar volume ratio. The reaction was carried out overnight. After removing the organic solvent under vacuum, 60% CHCl3 was added in a molar volume ratio. The mixture was washed with H2O, and the organic layer was collected. The organic layer was dried with anhydrous Na2SO4 and filtered to remove CHCl3. The filter cake was then purified by column chromatography to obtain the desired compound 2. Step 1.2: Compound 2, Compound 3 and DMF are added to a container at a molar volume ratio of 1:60:
100. The mixture is reacted overnight under reflux. The reaction mixture is then cooled, and excess acetone is added to the solution. The precipitate is filtered and washed with petroleum ether and acetone to obtain a yellow solid G.
4. The method for preparing a macrocyclic-mediated, specific detection supramolecular system of trivalent gold cucurbituril [7]-cyclodextrin cascade assembly as described in claim 1, characterized in that, The preparation method of the ternary supramolecular assembly solution of the supramolecular system described in step 2 is as follows: Step 2.1: Add 4 equivalents of cucurbituril [7] to G prepared in step 1, and obtain a binary supramolecular system by mechanical stirring. ; Step 2.2: After forming the binary supramolecular system, SBE-β-CD is further added to the solution to form a ternary supramolecular system. .
5. A macrocyclic-mediated supramolecular system for the specific detection of trivalent gold using a cucurbituril[7]-cyclodextrin cascade assembly prepared by the method of any one of claims 1 to 4.
6. The application of the cucurbituril[7]-cyclodextrin cascade assembly supramolecular system for the specific detection of trivalent gold as described in claim 5, characterized in that, The application is for detecting Au in water or biological samples. 3+ .