A six-membered cucurbitacin-based supramolecular framework material and its preparation method and application

Abstract

The present invention relates to the technical field of chemical synthesis, and in particular to a six-membered cucurbitacin-based supramolecular framework material and a preparation method and application thereof. The preparation method comprises: placing 4,4'-biphenyl disulfonic acid and a six-membered cucurbitacin in water and stirring evenly to obtain a mixed solution, adding a lanthanum nitrate solution as an inducer to the mixed solution, and continuously placing the mixed solution in a hydrothermal reactor for heating, cooling the product, standing it, and drying it to obtain a six-membered cucurbitacin-based supramolecular framework material. The fluorescent probe in the present invention is useful for detecting Cu in water. 2+ The invention has the characteristics of convenient and quick operation, good selectivity and reusability.

Description

Technical Field

[0001] The invention relates to the technical field of chemical synthesis, and in particular to a six-membered cucurbitacin-based supramolecular framework material and a preparation method and application thereof. Background Art

[0002] During industrial production activities, heavy metal ions are released into the environment, entering rivers, lakes, oceans and soil. Moreover, heavy metal ions continue to circulate with the water cycle and atmospheric cycle and enter the ecological environment. Heavy metal ions are highly toxic, persistent and cumulative, causing serious harm to human health. Therefore, it is imperative to develop reliable, rapid, sensitive and simple methods for detecting heavy metal residues.

[0003] At present, the traditional detection methods include atomic absorption spectroscopy (AAS), inductively coupled plasma optical emission spectroscopy (ICP-OES), and inductively coupled plasma mass spectrometry (ICP-MS). These methods are usually very cumbersome and expensive to detect, and cannot be widely used.

[0004] Fluorescence sensing is a sensing technology based on the change of fluorescence signals. As a method for detecting target pollutants, it has the following advantages: high sensitivity, high selectivity, real-time monitoring, non-destructive detection, and ease of use. Therefore, it has broad application prospects in detecting pollutants. However, there are few reports on this type of material.

[0005] Therefore, a six-membered cucurbitacin-based supramolecular framework material fluorescent probe was invented for the detection of heavy metal ions in water, which is of great significance for environmental protection. Summary of the invention

[0006] The first aspect of the present invention provides a method for preparing a six-membered cucurbitacin-based supramolecular framework material, comprising:

[0007] 4,4'-biphenyldisulfonic acid and six-membered cucurbitacin are placed in water and stirred evenly to obtain a mixed solution, lanthanum nitrate solution is added to the mixed solution as an inducer, and the mixed solution is continuously heated in a hydrothermal reactor. The product is cooled, allowed to stand, and dried to obtain a six-membered cucurbitacin-based supramolecular framework material.

[0008] In some embodiments, the molar ratio of the 4,4'-biphenyldisulfonic acid to the six-membered cucurbitacin is 1:(1-1.1).

[0009] Furthermore, the molar ratio of the 4,4'-biphenyldisulfonic acid to the six-membered cucurbitacin is 1:1.

[0010] In some embodiments, the heating reaction conditions are: first raise the temperature of the mixed solution to 180°C, keep the temperature constant for 10 hours, then cool down to 50°C at a rate of 1°C / 10min, keep the temperature constant for 10 hours, then cool down to 30°C at a rate of 1°C / 10min, keep the temperature constant for 12-24 hours.

[0011] The second aspect of the present invention provides a six-membered cucurbitacin-based supramolecular framework material obtained by the above-mentioned preparation method.

[0012] In some embodiments, the molecular formula of the six-membered cucurbitacin-based supramolecular framework material is: 192 H 184 N 96 O 72 S8.

[0013] Furthermore, the relative molecular mass of the six-membered cucurbitacin-based supramolecular framework material is 15563.7.

[0014] The third aspect of the present invention provides an application of a six-membered cucurbitacin-based supramolecular framework material, wherein the six-membered cucurbitacin-based supramolecular framework material is used to detect Cu in water. 2+ .

[0015] In some embodiments, Cu 2+ The detection limit is 0.0849M-0.1041M.

[0016] A fourth aspect of the present invention provides a Cu in water 2+ The detection method comprises: preparing a six-membered cucurbit ring-based supramolecular framework material into a probe standard solution, recording the fluorescence emission spectrum of the probe standard solution at an excitation wavelength of 235 nm; 2+ A single aqueous solution of Cu was added to the probe standard solution and the concentration of Cu 2+ The fluorescence spectrum of the probe standard solution produced at an excitation wavelength of 235nm; the change value of the fluorescence intensity at the maximum emission wavelength of 320nm was calculated to achieve the detection of Cu in water 2+ Detection.

[0017] A fifth aspect of the present invention provides a method for detecting Cu in water. 2+ The probe standard solution is prepared by dispersing a six-membered cucurbitacin-based supramolecular framework material in water.

[0018] In some embodiments, the method for preparing the probe standard solution includes: grinding the six-membered cucurbitacin-based supramolecular framework material into powder, and ultrasonically immersing it in deionized water to obtain a probe standard solution; the concentration of the probe standard solution is 1 mg / mL.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] 1. The present invention provides a method for preparing a six-membered cucurbitacin-based supramolecular framework material, which utilizes sulfonic acid-containing organic ligands to achieve bridging through non-covalent forces, and synthesizes a "sheet-like" three-dimensional framework structure by adjusting the material ratio and temperature. It has the advantages of simple operation and high yield.

[0021] 2. Compared with the prior art, the fluorescent probe in the present invention is more effective in detecting Cu 2+ The method has the characteristics of convenient and fast operation, good selectivity, low detection limit and reusability. It only needs to synthesize the materials in advance, put the materials of the invention into a specific polluted environment, preserve the water samples for detection by fluorescence spectrometer, and then it can be known whether the water environment contains pollutants.

[0022] 3. Compared with the prior art, the synthesis route of the material of the present invention is convenient and fast, with high yield, can overcome background interference during the detection process, has excellent stability, and can be used as a portable, temporary and rapid detection method for Cu in water environment. 2+ . BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0024] Figure 1 This is the crystal structure diagram of the six-membered cucurbitacin-based supramolecular framework material prepared in Example 1.

[0025] Figure 2 This is the PXRD structural characterization of the six-membered cucurbitacin-based supramolecular framework material prepared in Example 1.

[0026] Figure 3 This is the thermogravimetric (TG) characterization of the six-membered cucurbitacin-based supramolecular framework material prepared in Example 1.

[0027] Figure 4 This is a diagram of the experimental results of Example 4.

[0028] Figure 5 This is a diagram of the experimental results of Example 5.

[0029] Figure 6 This is a diagram of the experimental results of Example 6. DETAILED DESCRIPTION

[0030] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] Example 1

[0032] The present embodiment provides a six-membered cucurbitacin-based supramolecular framework material, and the preparation method includes: weighing Q[6] (23.52 mg, 0.02 mmol), placing it in a reagent tube containing 7 mL of distilled water, ultrasonically shaking for 30 min to disperse the Q[6] particles uniformly, and then adding 4,4'-biphenyl disulfonic acid (6.2866 mg, 0.02 mmol) to the above solution, ultrasonically shaking for 5 min to obtain a mixed solution. Add 0.1 mL of lanthanum nitrate solution with a concentration of 32.4 mg / mL as an inducer to the mixed solution, place the mixed solution in a hydrothermal reactor, program the temperature to 180°C, keep the temperature constant for 10 h, then cool it to 50°C at 1°C / 10 min, keep the temperature constant for 10 h, then cool it to 30°C at 1°C / 10 min, keep the temperature constant for 12.0 h, turn off the program temperature oven, cool the hydrothermal reactor to room temperature, let it stand for 24 h, and directly filter to obtain orange-yellow block crystals.

[0033] The yield of the six-membered cucurbitacin-based supramolecular framework material in this example is 48%.

[0034] Structural characterization Figure 1 and Figure 2 The results showed that the obtained sample was pure phase; thermogravimetric analysis showed Figure 3 .Depend on Figure 1 It can be seen that the microstructure of the six-membered cucurbitacin-based supramolecular framework material was characterized by X-ray single crystal diffractometer, which provides theoretical support for Example 1 to be used as a fluorescent probe; Figure 2 It can be seen that the PXRD spectrum proves that the obtained six-membered cucurbitacin-based supramolecular framework material is a pure phase, proving that the six-membered cucurbitacin-based supramolecular framework material of Example 1 can be stably synthesized; Figure 3 It can be seen that the TG spectrum proves that the six-membered cucurbitacin-based supramolecular framework material of Example 1 has excellent thermal stability and can withstand a high temperature of 400°C, providing theoretical support for the multi-environment application of the material.

[0035] Example 2

[0036] The present embodiment provides a six-membered cucurbitacin-based supramolecular framework material probe standard solution, and the preparation method comprises: weighing 50 mg of the sample obtained in Example 1, grinding it thoroughly, adding 10 mL of distilled water, ultrasonically shaking it for 30 minutes, and then transferring it to a 50 mL volumetric flask to make up the volume, to obtain a probe standard solution with a concentration of 1 mg / mL.

[0037] Example 3

[0038] This embodiment provides a method for detecting Cu 2+ The method comprises: adding 2 mL of a probe standard solution with a concentration of 1 mg / mL into a quartz glass vessel, fixing the excitation wavelength at 235 nm, and measuring the fluorescence spectrum within the range of 255-450 nm. 2+ After adding the standard solution, stir the suspension at a constant rate to ensure uniform mixing, and measure a series of fluorescence curves until the ordinate value of the fluorescence curve changes slowly, then stop the titration operation.

[0039] The fluorescence emission intensity of the probe at 320 nm was used and the nonlinear Stern-Volmer equation I0 / I=Ae k[Q] + B (where I0 and I are the fluorescence emission intensities of the suspension before and after the addition of MClx solution, A, B and k are constants, and [Q] is the concentration of ions) and fitted according to K SV =A×k Calculate the quenching constant and measure the standard deviation σ of the blank value 5 times. According to the formula, the detection limit (DL) = 3σ / K SV , calculate the fluorescent probe to detect Cu 2+ The detection limit of the standard solution is 0.0849M-0.1041M.

[0040] Example 4

[0041] This embodiment provides the detection of the fluorescence property of the six-membered cucurbit ring-based supramolecular framework material, and the specific method is: add 3mL of the probe standard solution to a quartz cuvette with smooth surfaces, measure the emission spectrum of the probe standard solution with an incident wavelength of 235nm as the excitation wavelength, and record the data at the peak as I0, and add 50μL of 0.1M sodium chloride, potassium chloride, rubidium chloride, cesium chloride, magnesium chloride, calcium chloride, strontium chloride, barium chloride, cobalt chloride, nickel chloride, copper chloride, cadmium chloride, zinc chloride, and manganese chloride solution, respectively, and record the data at the peak as I. The quenching efficiency formula is Quenching Efficiency = (I0-I) / I0*100%.

[0042] The experimental results are shown in Figure 4 ,Depend on Figure 4 It can be seen that the fluorescence spectrum proves that the six-membered cucurbit ring-based supramolecular framework material obtained in Example 1 has a strong effect on Cu after the metal ion solution is added. 2+ Specific fluorescence quenching recognition was generated, and the quenching efficiency reached 40%, proving that the six-membered cucurbitacin-based supramolecular framework material prepared in Example 1 has the potential to become a "Turn-Off" type optical probe.

[0043] Example 5

[0044] This example provides a six-membered cucurbit ring-based supramolecular framework material fluorescent probe prepared in Example 2 for Cu 2+ The specific method for detecting the aqueous solution is as follows: 3 mL of the probe standard solution is added to a quartz cuvette with smooth surfaces, the emission spectrum of the probe standard solution is measured with an incident wavelength of 235 nm as the excitation wavelength, and the data at the peak is recorded as I0. A quantitative volume of Cu is added gradually with a pipette. 2+ The peak data of aqueous solution is recorded as I, and the volume of pollutant solution added is recorded at the same time. The quenching constant I0 / I=Aek[Q]+B (where A, K, B are all constants, [Q] is the concentration. Quenching constant Ksv=A*K) is calculated using the Stern-Volmer equation. The detection limit is calculated according to the detection limit formula 3σ / s (σ is the standard deviation, s is the quenching constant).

[0045] The experimental results are shown in Figure 5 , Figure 5 The fluorescence quenching phenomenon can be described. Through the obtained experimental parameters, it can be judged whether the six-membered cucurbitacin-based supramolecular framework material prepared in Example 1 has the performance as a fluorescent probe, and a theoretical basis can be provided for this purpose. Figure 5 It can be seen that the fluorescence quantitative titration spectrum proves that as the copper ion content increases, the fluorescence of the six-membered cucurbitacin-based supramolecular framework material prepared in Example 1 is gradually quenched, indicating that it can be used as a fluorescent probe for detecting copper ions.

[0046] Example 6

[0047] This example provides a six-membered cucurbit ring-based supramolecular framework material fluorescent probe prepared in Example 2 for multiple cycles to detect Cu 2+ The specific method for detecting the aqueous solution is as follows: after each fluorescence titration experiment of Example 4, the solid powder is collected and washed with a distilled water solution, the solid powder is retained after centrifugation, and the quenching efficiency of the solid powder for copper ions is retested after drying.

[0048] The experimental results are shown in Figure 6 ,Depend on Figure 6 It can be seen that the six-membered cucurbit ring-based supramolecular framework material fluorescent probe prepared by the present invention can still maintain a high recognition ability in the first three cycles, and after five cycles, the fluorescence recognition ability decreases. This shows that it can be used as a potential Cu 2+ Fluorescent probes.

[0049] Comparative Example 1

[0050] This comparative example provides a six-membered cucurbitacin-based supramolecular framework material, and the preparation method is basically the same as that of Example 1, except that Q[6] (23.52 mg, 0.02 mmol) and 4,4′-biphenyldisulfonic acid (12.5732 mg, 0.04 mmol) are used.

[0051] The yield of the six-membered cucurbitacin-based supramolecular framework material in this comparative example is 48.5%.

[0052] Comparative Example 2

[0053] This comparative example provides a six-membered cucurbitacin-based supramolecular framework material, and the preparation method is basically the same as that of Example 1, except that Q[6] (11.76 mg, 0.01 mmol) and 4,4′-biphenyldisulfonic acid (6.2866 mg, 0.02 mmol) are used.

[0054] The yield of the six-membered cucurbitacin-based supramolecular framework material in this comparative example is 39.2%.

[0055] Comparative Example 3

[0056] This comparative example provides a six-membered cucurbitacin-based supramolecular framework material, and the preparation method is substantially the same as that of Example 1, except that the temperature is programmed to rise to 120°C.

[0057] The yield of the six-membered cucurbitacin-based supramolecular framework material in this comparative example is 30.7%.

[0058] Comparative Example 4

[0059] This comparative example provides a six-membered cucurbitacin-based supramolecular framework material, and the preparation method is substantially the same as that of Example 1, except that the temperature is programmed to rise to 150°C.

[0060] The yield of the six-membered cucurbitacin-based supramolecular framework material in this comparative example is 35%.

[0061] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. An application of a six-membered cucurbitacin-based supramolecular framework material, characterized in that: The six-membered cucurbit ring-based supramolecular framework material is used to detect Cu in water 2+ ; The preparation method of the six-membered cucurbitacin-based supramolecular framework material comprises: placing 4,4'-biphenyldisulfonic acid and a six-membered cucurbitacin in water and stirring them uniformly to obtain a mixed solution, adding a lanthanum nitrate solution as an inducer to the mixed solution, and continuously placing the mixed solution in a hydrothermal reactor for heating, cooling the product, standing it, and drying it to obtain the six-membered cucurbitacin-based supramolecular framework material; The molar ratio of the 4,4'-biphenyldisulfonic acid to the six-membered cucurbitacin is 1:1; The heating reaction conditions are as follows: firstly, the mixed solution is heated to 180°C, kept at the constant temperature for 10 hours, then cooled to 50°C at a rate of 1°C / 10min, kept at the constant temperature for 10 hours, then cooled to 30°C at a rate of 1°C / 10min, kept at the constant temperature for 12.0-24.0 hours.

2. The use according to claim 1, characterized in that: Cu 2+ The detection limit is 0.0849M-0.1041M.

3. A kind of Cu in water 2+ The detection method is characterized in that include: The six-membered cucurbit ring-based supramolecular framework material of claim 1 is made into a probe standard solution, and the fluorescence emission spectrum generated by the probe standard solution at an excitation wavelength of 235 nm is recorded; 2+ A single aqueous solution of Cu was added to the probe standard solution and the concentration of Cu 2+ The fluorescence spectrum of the probe standard solution produced at an excitation wavelength of 235nm; the change value of the fluorescence intensity at the maximum emission wavelength of 320nm was calculated to achieve the Cu in water 2+ Detection.

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