Supramolecular compound of bicyclic compound and application of supramolecular compound in selective recognition of cerium

Abstract

The invention discloses a supramolecular compound with a specific spatial size, which belongs to the field of supramolecular chemistry, and the molecular structural formula of the supramolecular compound is as follows: the invention aims to synthesize a cyclic compound with a specific cavity size through a simple and efficient method, and the internal cavity of the cyclic compound has a size of about 3 angstroms; specific cations (such as cerium ions) can be effectively identified, and the cyclic compound becomes a novel supramolecular material for extracting rare earth elements.

Description

Technical Field

[0001] This invention belongs to the field of supramolecular chemistry, particularly to macrocyclic compounds with cavities of specific sizes. Background Technology Cyclic compounds, due to their pre-organized structure and specific cavity sizes, exhibit higher selectivity and stronger complexation ability for guest molecules. For the host molecule to achieve high selectivity for the guest molecule, two conditions must be met: firstly, the cavity size of the host molecule must be well-matched to the size of the acceptor molecule; secondly, the recognition groups modified on the host molecule must have strong interactions with the guest molecule. Previously reported macrocyclic molecules often suffer from long synthetic routes and low yields. This chapter will introduce dynamically reversible bonds for the synthesis of macrocyclic molecules to address this low yield problem. Based on the excellent guest molecule recognition properties of imines and pyrroles and their derivatives, and the fact that ester groups can act as hydrogen bond acceptors, their molecular recognition ability is obvious. Therefore, compounds that combine hydrogen bond donors and acceptors often exhibit high complexation ability for guest molecules.

[0002] This invention constructs highly symmetric bicyclic compounds with imine, pyrrole, and ester groups as recognition functional groups, possessing multiple recognition sites and specific cavity sizes. These bicyclic compounds are expected to exhibit selective recognition properties for anions with small molecular radii and certain cations. Summary of the Invention

[0003] The purpose of this invention is to synthesize a cyclic compound with a specific cavity size of about 3 angstroms through a simple and efficient method. This cyclic compound can effectively recognize specific cations (such as cerium ions), and thus becomes a novel supramolecular material for extracting rare earth elements.

[0004] The target compound of this invention is a highly symmetrical bicyclic supramolecular compound with recognition function, and its structural formula is as follows:

[0005] The synthetic route for the highly symmetric bicyclic supramolecular compounds with recognition function is as follows: The reaction equation is: Synthesis of precursor compound C:

[0006] Synthesis of the target compound

[0007] Compound a and benzyl bromide compound b were dissolved in a solvent and stirred until completely dissolved to obtain a reaction solution. A base was added to the reaction solution to carry out the reaction. After the reaction was completed, the reaction solution was added to water to induce crystallization. The solution was filtered and washed to obtain compound c containing four aldehyde groups. Compound C was dissolved in a solvent and stirred until completely dissolved to obtain a reaction solution. Hydrazine hydrate was added to the reaction solution to carry out the reaction. After the reaction was completed, the solid in the reaction solution was separated, filtered, and washed to obtain a compound containing a bicyclic ring, i.e., a supramolecular compound.

[0008] Specific steps: The molar ratio of compound a to compound b is 4-6:1, preferably 4.4:1. The alkali includes potassium hydroxide and sodium hydroxide.

[0009] The molar ratio of compound c to hydrazine hydrate is 2-3:1, preferably 2.2:1. The solvent includes a mixed solution of methanol and chloroform.

[0010] In some specific embodiments, the following steps are included: Compound a and KOH were weighed into a container, and anhydrous DMF was added. After stirring at room temperature for 1 hour, compound b was weighed and added to the system, and the mixture was stirred at room temperature for 10-12 hours. After the reaction was complete, the solvent was removed by vacuum distillation, and the mixture was then extracted three times with DCM:H2O = 1:1 (V:V). The organic phases were combined, dried with anhydrous sodium sulfite, and the solvent was removed by rotary evaporation to obtain the crude product. The crude product was then purified by column chromatography using DCM:MeOH = 100:3 (V:V) as the eluent, resulting in a grayish-white solid compound. This solid compound was then recrystallized multiple times using EA to obtain a white solid compound.

[0011] In the synthesis of the target compound, the four-arm compound C was weighed into a round-bottom flask, and then CHCl3 was added. The mixture was sonicated for 5 minutes until completely dissolved in chloroform, at which point the system was a pale yellow, clear liquid. Then, hydrazine hydrate was weighed into a volumetric flask, methanol was added, and after mixing, the mixture was transferred to the above system and stirred at room temperature for 20-24 hours. After the reaction was complete, a large amount of yellow precipitate was observed to form in the system. This precipitate was filtered, and the collected yellow solid was recrystallized twice with methanol. After drying, the target compound was obtained as a yellow solid.

[0012] The present invention also provides an application of the supramolecular compound of the aforementioned bicyclic compound in selectively recognizing cerium among metal elements.

[0013] The application of the supramolecular compound in selectively recognizing the metallic element cerium from solution, wherein the solution includes dichloromethane and N,N-dimethylformamide.

[0014] The metallic elements mentioned include one or more of nickel, cerium, lanthanum, dysprosium, europium, barium, zinc, cobalt, and chromium.

[0015] A supramolecular material for recognizing the metallic element cerium, comprising the supramolecular compound having a bicyclic structure.

[0016] The advantages and beneficial effects of this invention are as follows: (1) The method for synthesizing and separating supramolecular compounds with specific cavity structures of the present invention is simple and the raw materials are readily available.

[0017] (2) The cavity size of the compound molecule with a specific cavity structure of the present invention is 3 angstroms, which can complex halogen anions and some cations with small molecular radii, thereby enabling effective recognition. This supramolecular material is expected to become a new material for the extraction of rare earth elements.

[0018] (3) The target compound is stable and can be efficiently recycled. Attached Figure Description

[0019] Figure 1 shows the color change of a dichloromethane solution of the target compound in Example 3 of the present invention after the addition of various cations. Detailed Implementation

[0020] The features and advantages of the present invention can be further understood through the following detailed description in conjunction with the accompanying drawings. The provided embodiments are merely illustrative of the method of the present invention and do not limit the rest of the content disclosed herein in any way.

[0021] The present invention will be further described below with reference to embodiments and accompanying drawings: Example 1 Synthesis of precursor compound C

[0022] A 100 mL round-bottom flask was selected, and compound a (0.5 g, 2.56 mmol) and KOH (0.14 g, 2.56 mmol) were weighed into the flask. Anhydrous DMF (40 mL) was added, and the mixture was stirred at room temperature for two hours. Then, compound b (0.26 g, 0.58 mmol) was weighed and added to the above system, and the mixture was stirred at room temperature for 12 hours. After the reaction was completed, the solvent was removed by vacuum distillation, and the mixture was extracted three times with DCM:H2O = 1:1 (V:V). The organic phases were combined, dried with anhydrous sodium sulfite, and the solvent was removed by rotary evaporation to obtain the crude product. The crude product was then purified by column chromatography using DCM:MeOH = 100:3 (V:V) as the eluent to obtain a grayish-white solid compound. This was then recrystallized multiple times with EA to obtain a white solid compound c (0.39 g, 0.435 mmol), with a yield of 75%.

[0023] 1 H NMR (400 MHz, DMSO- d 6) δ 12.42 (s, 4H), 9.79 (s, 4H), 7.74 (s, 2H), 5.51 (s, 8H), 2.58 (dd,J = 21.6, 7.3 Hz, 16H), 0.98 (d, J = 26.6 Hz, 24H). 13 C NMR (101 MHz, DMSO-) d 6) δ 182.2, 160.4, 132.9, 131.0, 63.4, 40.6, 40.2, 39.9,39.7, 39.5, 17.3, 17.1, 16.5, 16.2.HRMS: m / z ; [ M +Na] + : calcd forC 50 H 58 N4O 12 Found: 929.39434.

[0024] Example 2 Synthesis of the target compound

[0025] A 100 mL round-bottom flask was used to weigh out the four-arm compound c (300 mg, 0.33 mmol). Then, 15 mL of CHCl3 was added, and the mixture was sonicated for 5 min to completely dissolve it in chloroform, resulting in a pale yellow, clear liquid. Next, hydrazine hydrate (165.3 mg, 3.3 mmol) was weighed into a volumetric flask, and 35 mL of methanol was added. After mixing, the mixture was transferred to the above system and stirred at room temperature for 24 h. After the reaction was complete, a large amount of yellow precipitate was observed to form. The precipitate was filtered, and the collected yellow solid was recrystallized twice with methanol. After drying, the target compound was obtained as a yellow solid (252.2 mg), with a yield of 85%.

[0026] 1 H NMR (400 MHz, CDCl3) δ 11.30 (s, 2H), 9.22 (s, 2H), 8.45 (s, 2H), 7.73 (d, J = 15.4 Hz, 4H), 5.36 (s, 8H), 2.85 (dd, J = 18.4, 8.0 Hz, 8H), 2.61(t, J = 7.3 Hz, 8H), 1.29 – 1.08 (m, 24H). 13C NMR (101 MHz, CDCl3) δ 159.8,158.6, 150.4, 144.4, 138.23, 135.6, 135.5, 134.8, 134.7, 134.6, 134.4, 134.2,132.8, 126.1, 125.8, 125.8, 121.2, 120.2, 64.4, 60.5, 17.7, 17.6, 17.2, 17.1,16.9, 16.8, 15.5, 15.3.HRMS: m / z ; [ M +Na] + : calcd for C 50 H 58 N8O8 found: 921.42698. Example 3 The target compound was formulated to a concentration of 3.12 × 10⁻⁶. -6 In a dichloromethane solution of M, the addition of the organic base N,N-diisopropylethylamine (DIPEA) reacts with the proton H of the NH bond in pyrrole, making the cavity within the target compound's ring more conducive to complexation with metal cations. The color changes of the target compound and those after the addition of 5 equivalents of various cations (nickel acetate, cerium acetate, lanthanum acetate, dysprosium acetate, europium acetate, barium acetate, zinc acetate, cobalt acetate, and chromium acetate) were observed.

[0027] Figure 1 The color change after adding various cations to the target compound following the addition of DIPEA is shown above. Figure 1 As shown, the first column shows the state of various cations after being added to methanol solvent, and the second column shows the state of the target compound after being added to DIPEA followed by various cations (except for bottle 1). Bottle 1 shows the state of the target compound after being added to DIPEA (clear and transparent). Bottles 2, 3, 4, 5, 6, 7, 8, 9, and 10 show the state of the target compound after being added to DIPEA, followed by the addition of nickel acetate, cerium acetate, lanthanum acetate, dysprosium acetate, europium acetate, barium acetate, zinc acetate, cobalt acetate, and chromium acetate, respectively. It was observed that the solution in bottle 3, after the addition of cerium acetate, changed from clear and transparent to light orange. By comparing the color with that without the addition of metals, the target compound can effectively react with Ce. 2+ Perform identification.

Claims

1. A supramolecular compound of a bicyclic compound, characterized in that, The molecular structure is as follows: 。 2. The method for synthesizing the supramolecular compound of the bicyclic compound according to claim 1, characterized in that, The synthesis route is as follows: ； Compound a and benzyl bromide compound b were dissolved in a solvent and stirred until completely dissolved to obtain a reaction solution. A base was added to the reaction solution to carry out the reaction. After the reaction was completed, the reaction solution was added to water to induce crystallization. The solution was filtered and washed to obtain compound c containing four aldehyde groups. Synthetic route of the target compound: ； Compound C was dissolved in a solvent and stirred until completely dissolved to obtain a reaction solution. Hydrazine hydrate was added to the reaction solution to carry out the reaction. After the reaction was completed, the solid in the reaction solution was separated, filtered, and washed to obtain a compound containing a bicyclic ring, i.e., a supramolecular compound.

3. The synthesis method according to claim 2, characterized in that, During the synthesis of precursor c, the molar ratio of compound a to compound b is 4-6:1, preferably 4.4:

1.

4. The synthesis method according to claim 2, characterized in that, The method for synthesizing the target compound, wherein the molar ratio of compound c to hydrazine hydrate is 2-3:1, preferably 2.2:

1.

5. The synthesis method according to claim 2, characterized in that, The reaction temperature is room temperature, and the reaction time is 10-24 hours.

6. The supramolecular compound prepared by the method according to any one of claims 2-5, characterized in that, The supramolecular compound is a cyclic compound with a specific cavity size of 3 angstroms.

7. The application of the supramolecular compound of the bicyclic compound of claim 6 in the selective recognition of cerium among metal elements.

8. The application according to claim 7, characterized in that, The application of the supramolecular compound in selectively recognizing the metallic element cerium from solution, wherein the solution comprises dichloromethane and N,N-dimethylformamide.

9. The application according to claim 7, characterized in that, The metallic elements mentioned include one or more of nickel, cerium, lanthanum, dysprosium, europium, barium, zinc, cobalt, and chromium.

10. A supramolecular material for recognizing the metallic element cerium, comprising the supramolecular compound having a bicyclic structure as described in claim 1.

Images