C3 symmetrical conical mononuclear metal organic cage compound as well as preparation and application thereof

Abstract

The invention discloses a C3 symmetrical conical mononuclear metal organic cage compound as well as preparation and application thereof. The C3 symmetrical conical mononuclear metal organic cage compound comprises a metal cation node and a conjugate of a tridentate organic ligand and organic amine, wherein the conjugate is in coordination connection with the metal cation node; the tridentate organic ligand is formed by connecting a C3 symmetrical bottom center structure with three support arm structures through an ether chain; the organic amine is aromatic amine and / or aliphatic amine; the center structure of the C3 symmetrical bottom is C3 symmetrical polybasic aromatic phenol; a support arm structure contains benzyl and ether chain groups, and the tail end of the support arm structure is a pyridine-2-formaldehyde group; the C3 symmetric conical mononuclear metal organic caged compound is formed by self-assembly of a tridentate organic ligand and aliphatic amine under solvothermal conditions, has a unique cavity structure, and can realize high-sensitivity anion recognition; the product is high in yield and stable in structure, and the problems that a traditional multi-core metal cage is complex in synthesis and low in yield, and a cavity is difficult to accurately regulate and control are effectively solved.

Description

Technical Field

[0001] This invention relates to the interdisciplinary fields of supramolecular chemistry and coordination chemistry, and in particular to a C3-symmetric cone-shaped mononuclear metal-organic cage compound and its preparation and application. Background Technology

[0002] Metal-organic cages (MOCs) are discrete supramolecular structures formed by the self-assembly of metal ions and organic ligands through coordination bonds. These compounds possess well-defined cavities and designable channels, and are widely used in molecular recognition, catalysis, drug delivery, and environmental remediation.

[0003] The main shortcomings of existing metal-organic cages (MOCs) include: (1) poor stability, such as the Pd2L4 spherical cage (L is a bidentate ligand) which is prone to dissociation in physiological environment; (2) functionally, it is difficult to construct ordered ion / electron confined transport channels by means of the induction effect of anions, which leads to limited efficiency in fields such as electrocatalysis, batteries or sensors; (3) the synthesis of polynuclear structures is complicated, and the cost of systems that rely on noble metals such as Pd(II) and Pt(II) is high, making it difficult to apply on a large scale.

[0004] Therefore, it is essential to provide a technical solution for a mononuclear metal-organic cage compound that is structurally stable, has a high yield, and possesses anion recognition capability. Summary of the Invention

[0005] In view of this, this application provides a C3-symmetric cone-shaped mononuclear metal-organic cage compound and its preparation and application, in order to solve the problem of how to provide a mononuclear metal-organic cage compound with stable structure, high yield and anion recognition capability.

[0006] To achieve the above technical objectives, this application adopts the following technical solution: In a first aspect, this application provides a C3-symmetric cone-shaped mononuclear metal-organic cage compound comprising a metal cation node and a combination of a tridentate organic ligand coordinated to the metal cation node and an organic amine; the tridentate organic ligand is composed of a C3-symmetric bottom central structure connected by three branch arm structures via ether chains; the organic amine is an aromatic amine and / or an aliphatic amine; the C3-symmetric bottom central structure is a C3-symmetric polyphenolic compound; the branch arms contain benzyl and ether chain groups, and the ends are pyridine-2-carboxaldehyde groups.

[0007] Preferably, the outrigger structure is selected from formula (II): Equation (II), where n is a natural number; Preferably, the symmetrical bottom center structure of C3 is selected from formula (Ⅲ): Formula (III).

[0008] Preferably, the fatty amine is selected from one or more of tris(2-aminoethyl)amine and tris(3-aminopropyl)amine; the aromatic amine is selected from one or more of aniline, methylaniline, halogenated aniline, methoxyaniline, phenylaniline, and benzylaniline.

[0009] Preferably, the metal cation is selected from one of Cr(II), Mn(II), Fe(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II), Rh(II) / (III), and Ru(II) / (III).

[0010] Preferably, the three arms have the same structure.

[0011] Secondly, this application provides a method for preparing a C3-symmetric cone-shaped mononuclear metal-organic cage compound, comprising the following steps: Obtaining tridentate organic ligands; A tridentate organic ligand, an organic amine, and a metal salt are mixed in an organic solvent and subjected to a coordination self-assembly reaction to obtain a C3-symmetric cone-shaped mononuclear metal-organic cage compound.

[0012] The preferred method for preparing the tridentate organic ligand is as follows: Obtain the intermediate body of the extended arm; Using extended-arm intermediates and C3-symmetric polyphenols as raw materials, etherification reactions were carried out in organic solvents under the conditions of azodicarbonate diester, phosphine reagent and inert atmosphere to obtain tridentate ligand precursors; The tridentate ligand precursor was subjected to hydrolysis protection under acidic conditions to obtain the tridentate organic ligand.

[0013] Preferably, the steps for obtaining the extended arm intermediate are as follows: Using a pyridinaldehyde protecting body containing boric acid / ester and a halotetraphenyl derivative containing benzyl alcohol as raw materials, a coupling reaction was carried out in an organic solvent under palladium catalyst, alkaline and inert atmosphere conditions to obtain an extended-arm intermediate containing benzyl alcohol.

[0014] Preferably, the steps for obtaining the extended-arm intermediate are as follows: using a halopyridine aldehyde protectant and a boric acid / ester containing a phenolic hydroxyl group as raw materials, a coupling reaction is carried out in an organic solvent under the conditions of palladium catalyst, alkali and inert atmosphere to obtain a biphenyl intermediate containing a phenolic hydroxyl group; using the biphenyl intermediate and an aromatic diol as raw materials, an etherification reaction is carried out in an organic solvent under the conditions of azodicarbonate diester, phosphine reagent and inert atmosphere to obtain the extended-arm intermediate.

[0015] Thirdly, this application provides a crystal material prepared from a C3-symmetric cone-shaped mononuclear metal-organic cage compound according to a crystal culture template.

[0016] Fourthly, this application provides an application of a symmetrical cone-shaped mononuclear metal-organic cage compound in the field of anion detection.

[0017] The beneficial effects of this application are as follows: This application is formed by the self-assembly of a tridentate organic ligand (C3 symmetric ligand) and aliphatic amine under solvothermal conditions. The preparation method includes ligand synthesis, metal coordination self-assembly and crystallization purification steps. The resulting C3 symmetric cone-shaped mononuclear metal-organic cage compound has a unique cavity structure and can achieve highly sensitive anion recognition. The preparation method of this application yields products with high yield and stable product structure, effectively overcoming the problems of complex synthesis, low yield and difficulty in precise control of cavity in traditional polynuclear metal cage synthesis. Attached Figure Description

[0018] Figure 1 For the reason C 3. Symmetrical ligand L1 is assembled with Zn(NTf2)2 and tris(2-aminoethyl)amine. C 3-Zn cage 1 HNMR spectrum; Figure 2 For the reason C 3. Symmetrical ligand L1 is assembled with Fe(BF4)2 and tris(2-aminoethyl)amine. C 3-Fe cage 1 HNMR spectrum; Figure 3 for C Chloride ion recognition process of 3-Zn cage and corresponding conditions under different equivalences 1 H NMR spectrum; Figure 4 A schematic diagram of the structure of a tridentate organic ligand; Figure 5 This is a schematic diagram of the overall structure of a C3-symmetric, cone-shaped, mononuclear metal-organic cage compound. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0020] This application provides a C3-symmetric cone-shaped mononuclear metal-organic cage compound comprising a metal cation node and a combination of a tridentate organic ligand coordinated to the metal cation node and an organic amine; the tridentate organic ligand is composed of a C3-symmetric bottom central structure connected by three arm structures via ether chains; the organic amine is an aromatic amine and / or an aliphatic amine; the C3-symmetric bottom central structure is a C3-symmetric polyphenol; the arm contains benzyl and ether chain groups, and the terminal is a pyridine-2-carboxaldehyde group.

[0021] This application describes a C3-symmetric cone-shaped mononuclear metal-organic cage compound. The compound uses a metal cation in a metal salt as a node and a pre-assembled tridentate organic ligand (C3-type organic ligand) as a conjugate with an aliphatic or aromatic amine. Through self-assembly, a C3-symmetric cone-shaped metal-organic cage compound is formed. The bottom structure connects to three supporting arms, the ends of which are connected to the same metal cation, forming a vertex. The overall geometry exhibits C3 symmetry, and the ratio of metal cation to tridentate organic ligand molecules is 1:1. A schematic diagram of the tridentate organic ligand structure is shown below. Figure 4 As shown, Figure 4 (a) is a schematic diagram of the overall tridentate organic ligand. Figure 4 (b) is a schematic diagram of the support structure of a tridentate organic ligand. Figure 4 (c) is a schematic diagram of the bottom central structure of a tridentate organic ligand; Figure 5 (a) is a schematic diagram of the overall structure of a C3-symmetric cone-shaped mononuclear metal-organic cage compound. Figure 5 (b) is a metal cation.

[0022] Among them, the tridentate organic ligand undergoes a Schiff base condensation reaction with aliphatic or aromatic amines, forming a complex through an imine bond, and then coordinates with a single metal ion to finally form a C3 symmetrical cone-shaped mononuclear organometallic cage compound.

[0023] In some embodiments, the structural formula of the tridentate organic ligand is selected from formula (I):

[0024]

[0025]

[0026] In some embodiments, corresponding Figure 4 (b) The outrigger structure is selected from formula (II): Equation (II), where n is a natural number; In some embodiments, corresponding Figure 4 (c) The symmetrical bottom center structure of C3 is selected from formula (Ⅲ): Formula (Ⅲ); the symmetrical bottom central structure of C3 is any one of a benzene ring modified with a phenolic hydroxyl group, triphenylamine, or 2,4,6-triphenyltriazine.

[0027] In some embodiments, the C3-symmetrical bottom central structure is triphenylphenol.

[0028] In some embodiments, the aliphatic amine is selected from one or more of tris(2-aminoethyl)amine and tris(3-aminopropyl)amine; the aromatic amine is selected from one or more of aniline, methylaniline, haloaniline, methoxyaniline, phenylaniline, and benzylaniline.

[0029] In some embodiments, the metal cation is selected from one of Cr(II), Mn(II), Fe(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II), Rh(II) / (III), and Ru(II) / (III).

[0030] In some embodiments, the three arms have the same structure.

[0031] This application provides a method for preparing a C3-symmetric cone-shaped mononuclear metal-organic cage compound, comprising the following steps: obtaining a tridentate organic ligand; mixing the tridentate organic ligand, an organic amine, and a metal salt in an organic solvent, and carrying out a coordination self-assembly reaction to obtain a C3-symmetric cone-shaped mononuclear metal-organic cage compound.

[0032] In some embodiments, the molar ratio of the tridentate organic ligand, organic amine, and metal salt is 1:1-1.15:1-1.3; the coordination self-assembly reaction is carried out at a temperature of 50-80°C for 10-20 hours; and the organic solvent includes acetonitrile and / or dimethyl sulfoxide.

[0033] In some embodiments, the metal salt is a divalent or trivalent transition metal salt.

[0034] In some embodiments, the metal salt is one of the metal salts of Cr(II), Mn(II), Fe(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II), Rh(II) / (III), and Ru(II) / (III).

[0035] In some embodiments, the anion of the metal salt includes one of tetrafluoroborate ion, nitrate ion, sulfate ion, chloride ion, bromide ion, iodide ion, hexafluorophosphate ion, trifluoromethanesulfonylimide ion, and trifluoromethanesulfonate ion.

[0036] In some embodiments, the preparation method of the tridentate organic ligand is as follows: S1. Using a halopyridine aldehyde protector and a boric acid / ester containing phenolic hydroxyl groups as raw materials, a coupling reaction is carried out in an organic solvent under palladium catalyst, alkaline and inert atmosphere conditions to obtain a biphenyl intermediate containing phenolic hydroxyl groups; S2. Using biphenyl intermediates and aromatic diols as raw materials, an etherification reaction is carried out in an organic solvent under the conditions of azodicarbonate diester, phosphine reagent and inert atmosphere to obtain an extended-arm intermediate; S3. Using an extended-arm intermediate and a C3-symmetrical polyphenol as raw material, an etherification reaction is carried out in an organic solvent under the conditions of azodicarbonate diester, phosphine reagent and inert atmosphere to obtain a tridentate ligand precursor; S4. The tridentate ligand precursor is subjected to hydrolysis protection under acidic conditions to obtain the tridentate organic ligand.

[0037] Specifically, in some embodiments, the preparation method of the tridentate organic ligand is as follows: S1. Using 5-bromo-2-(dimethoxymethyl)pyridine and 4-hydroxyphenylboronic acid as raw materials, under the conditions of palladium catalyst tetra(triphenylphosphine)palladium, potassium carbonate and inert atmosphere, the reaction is carried out in a mixed solvent of toluene, ethanol and water at 90-110℃ for 1-2 days to obtain a biphenyl intermediate containing phenolic hydroxyl groups. S2. Using a biphenyl intermediate containing a phenolic hydroxyl group and 1,3-benzenedimethanol as raw materials, the mixture is reacted in anhydrous tetrahydrofuran at 25-40°C for 2-3 days under the conditions of azodicarbonate diester, triphenylphosphine and an inert atmosphere to obtain an extended-arm intermediate. S3. Using the extended arm intermediate and pyrogallol as raw materials, the mixture is heated in anhydrous tetrahydrofuran at 25-40°C for 2-3 days under the conditions of azodicarbonate diester, triphenylphosphine and inert atmosphere to obtain the tridentate ligand precursor. S4. Mix the tridentate ligand precursor with acid, introduce nitrogen gas, and heat at 25-40℃ for 2-3 days to obtain the tridentate organic ligand.

[0038] This application provides a crystal material prepared from a C3-symmetric cone-shaped mononuclear metal-organic cage compound according to a crystal culture template. Different crystal culture templates yield crystal materials of different shapes, including but not limited to cylindrical, spherical, prismatic, and cubic shapes, which can be used to prepare core materials for intelligent detection devices and light change sensors.

[0039] This application provides an application of a symmetrical cone-shaped mononuclear metal-organic cage compound in the field of anion detection, such as the detection of chloride ions, fluoride ions, bromide ions, iodide ions, nitrate ions, sulfate ions, trifluoromethanesulfonate ions, and trifluoromethanesulfonamide ions.

[0040] The following specific embodiments further illustrate this solution.

[0041] Example 1 A C3-symmetric, cone-shaped, mononuclear, organometallic cage-like compound containing a Zn group. 2+ Nodes, and with Zn 2+ A combination of a tridentate organic ligand with tris(2-aminoethyl) via node coordination; the tridentate organic ligand is composed of three branched structures of tris(triphenol) connected by an ether chain; The outrigger structure is , where n=1; The preparation method of C3-symmetric cone-shaped mononuclear metal-organic cage compounds includes the following steps: K1. Obtaining tridentate organic ligands ( C 3. Symmetrical ligand L1), its preparation method is as follows: 5-bromo-2-(dimethoxymethyl)pyridine, 4-hydroxyphenylboronic acid, tetra(triphenylphosphine)palladium and potassium carbonate were added to 120 mL of a mixed solvent of toluene, ethanol and water with a volume ratio of 10:10:8 in a molar ratio of 5:6.25:0.25:25. Nitrogen gas was introduced and the mixture was heated at 110 °C for 1 day. After the reaction was completed, the mixture was processed to obtain compound (1). Equation (1); Compound (1), 1,3-benzenedimethanol and triphenylphosphine were added to 6 mL of anhydrous tetrahydrofuran in a molar ratio of 2:6:4. Nitrogen gas was introduced and 0.9 mL of azodicarboxylic acid diisopropionate was added dropwise at 0 °C. The mixture was heated at 40 °C for 3 days. After the reaction was completed, the mixture was processed to obtain compound (2). Equation (2); Compound (2), triphenylphenol and triphenylphosphine were added to 10 mL of anhydrous tetrahydrofuran in a molar ratio of 4.2:1:4. Nitrogen gas was introduced and 0.9 mL of diisopropionate azodicarbonate was added dropwise at 0 °C. The mixture was heated at 40 °C for 2 days. After the reaction was completed, the mixture was processed to obtain compound (3). Equation (3); Mix 0.5 g of compound (3) with 10 mL of 4 M HCl aqueous solution, purge with nitrogen gas, heat at 30 °C for 2 days, and process after the reaction to obtain compound (4), which is the tridentate organic ligand. Equation (4); K2. Weigh 103.02 mg (0.10 mmol) of tridentate organic ligand, 275.08 mg (0.12 mmol) of Zn(NTf2) and 16.09 mg (0.11 mmol) of tris(2-aminoethyl) and transfer them to a reaction flask containing 60 mL of acetonitrile solvent. Replace the nitrogen (or argon) gas three times under reduced pressure. Then heat the reaction at 80 °C for 25 hours. Filter the reaction solution through a 0.22 µm PTFE filter membrane. Transfer the filtrate to a crystallization container and slowly diffuse diethyl ether (diffusion rate: 1 mL / h). After 7 days, collect colorless prismatic crystals, wash them three times with diethyl ether, and dry them under vacuum (40 °C, 10-2 bar) to obtain 157.50 mg (90.1%) of the compound C3-L1-Zn cage of formula (5), which is a C3 symmetrical cone-shaped mononuclear metal-organic cage compound. Figure 1 For the reason C 3. Symmetrical ligand L1 is assembled with Zn(NTf2)2 and tris(2-aminoethyl)amine. C 3-L1-Zn cage 1 H NMR spectrum; Equation (5).

[0042] Example 2 A C3-symmetric, cone-shaped, mononuclear metal-organic cage-like compound containing an Fe group. 2+ Nodes, and with Fe 2+ A combination of a tridentate organic ligand with tris(2-aminoethyl) via node coordination; the tridentate organic ligand is composed of three branched structures of tris(triphenol) connected by an ether chain; The outrigger structure is , where n=1; Preparation method of C3 symmetrical cone-shaped mononuclear metal-organic cage compounds: K1. Obtaining tridentate organic ligands ( C 3. Symmetrical ligand L1), whose structure and preparation method are the same as in Example 1; K2. Weigh 103.02 mg (0.10 mmol) of tridentate organic ligand, 42.25 mg (0.125 mmol) of Fe(BF4)2·6H2O, and 16.09 mg (0.11 mmol) of tris(2-aminoethyl) and transfer them to a reaction flask containing 60 mL of acetonitrile solvent. Replace the nitrogen (or argon) gas three times under reduced pressure. Then heat the reaction at 80 °C for 25 hours. Filter the reaction solution through a 0.22 µm PTFE filter membrane. Transfer the filtrate to a crystallization container and slowly diffuse diethyl ether (diffusion rate: 1 mL / h). After 7 days, collect the colorless prismatic crystals, wash them three times with diethyl ether, and dry them under vacuum (40 °C, 10-2 bar) to obtain 120.58 mg (yield 89.2%) of compound C3-L1-Fe cage of formula (6), which is a C3 symmetrical cone-shaped mononuclear metal-organic cage compound. Figure 2 For the reason C 3. Symmetrical ligand L1 is assembled with Fe(BF4)2 and tris(2-aminoethyl)amine. C 3-L1-Fe cage 1 H NMR spectrum; Equation (6).

[0043] Example 3 A C3-symmetric, cone-shaped, mononuclear, organometallic cage-like compound containing a Zn group. 2+ Nodes, and with Zn 2+ A combination of a tridentate organic ligand with tris(2-aminoethyl) via node coordination; the tridentate organic ligand is composed of three branched structures of tris(triphenol) connected by an ether chain; The outrigger structure is , where n=1; The preparation method of C3-symmetric cone-shaped mononuclear organometallic cage compounds includes the following steps: K1. Obtaining tridentate organic ligands ( C 3. Symmetrical ligand L2), its preparation method is as follows: Compound (2), 4,4',4''-phosphotriol and triphenylphosphine were added to 10 mL of anhydrous tetrahydrofuran in a molar ratio of 4.2:1:4. Nitrogen gas was introduced and 0.9 mL of azodicarboxylic acid diisopropionate was added dropwise at 0 °C. The mixture was heated at 40 °C for 2 days. After the reaction was completed, the mixture was processed to obtain compound (7). Equation (7); Mix 0.5 g of compound (7) with 10 mL of 4 M HCl aqueous solution, purge with nitrogen gas, heat at 30 °C for 2 days, process after reaction to obtain compound (8), which is the tridentate organic ligand; Equation (8); K2. Weigh 119.64 mg (0.10 mmol) of tridentate organic ligand, 275.08 mg (0.12 mmol) of Zn(NTf2) and 16.09 mg (0.11 mmol) of tris(2-aminoethyl) and transfer them to a reaction flask containing 60 mL of acetonitrile solvent. Replace the nitrogen (or argon) gas three times under reduced pressure. Then heat the reaction at 80 °C for 25 hours. Filter the reaction solution through a 0.22 µm PTFE filter membrane. Transfer the filtrate to a crystallization container and slowly diffuse diethyl ether (diffusion rate: 1 mL / h). After 7 days, collect the colorless prismatic crystals, wash them three times with diethyl ether, and dry them under vacuum (40 °C, 10-2 bar) to obtain the compound C3-L2-Zn cage of formula (9), which is a C3 symmetrical cone-shaped mononuclear metal-organic cage compound. Equation (9).

[0044] Example 4 A C3-symmetric, cone-shaped, mononuclear, organometallic cage-like compound containing a Zn group. 2+ Nodes, and with Zn 2+ A combination of a tridentate organic ligand with tris(2-aminoethyl) via node coordination; the tridentate organic ligand is composed of three branched structures of tris(triphenol) connected by an ether chain; The outrigger structure is , where n=1; The preparation method of C3-symmetric cone-shaped mononuclear organometallic cage compounds includes the following steps: K1. Obtaining tridentate organic ligands ( C 3. Symmetrical ligand L3), its preparation method is as follows: Compound (2), 4,4',4''-(1,3,5-triazine-2,4,6-trimethylene)triol and triphenylphosphine were added to 10 mL of anhydrous tetrahydrofuran in a molar ratio of 4.2:1:4. Nitrogen gas was introduced, and 0.9 mL of azodicarboxylic acid diisopropionate was added dropwise at 0 °C. The mixture was heated at 40 °C for 2 days. After the reaction was completed, the mixture was processed to obtain compound (10). Equation (10); Mix 0.5 g of compound (10) with 10 mL of 4 M HCl aqueous solution, purge with nitrogen gas, heat at 30 °C for 2 days, and process after the reaction to obtain compound (11), which is the tridentate organic ligand. Equation (11); K2. Weigh 126.04 mg (0.10 mmol) of tridentate organic ligand, 275.08 mg (0.12 mmol) of Zn(NTf2) and 16.09 mg (0.11 mmol) of tris(2-aminoethyl) and transfer them to a reaction flask containing 60 mL of acetonitrile solvent. Replace the nitrogen (or argon) gas three times under reduced pressure. Then heat the reaction at 80 °C for 25 hours. Filter the reaction solution through a 0.22 µm PTFE filter membrane. Transfer the filtrate to a crystallization container and slowly diffuse diethyl ether (diffusion rate: 1 mL / h). After 7 days, collect the colorless prismatic crystals, wash them three times with diethyl ether, and dry them under vacuum (40 °C, 10-2 bar) to obtain the compound C3-L3-Zn cage of formula (12), which is a C3 symmetrical cone-shaped mononuclear metal-organic cage compound. Equation (12).

[0045] Example 5 A C3-symmetric, cone-shaped, mononuclear, organometallic cage-like compound containing a Zn group. 2+ Nodes, and with Zn 2+ A combination of a tridentate organic ligand with tris(2-aminoethyl) via node coordination; the tridentate organic ligand is composed of three branched structures of tris(triphenol) connected by an ether chain; The outrigger structure is ; The preparation method of C3-symmetric cone-shaped mononuclear organometallic cage compounds includes the following steps: K1. Obtaining tridentate organic ligands ( C 3. Symmetrical ligand L4), its preparation method is as follows: 2-(dimethoxymethyl)-5-(4,4,5,5-tetramethyl-1,3,2-dioxoboronyl-2-yl)pyridine, (4'-(1-(4-(6-bromopyridin-3-yl)phenyl)-2,2-diphenylvinyl)-[1,1'-biphenyl]-3-yl)methanol, tetra(triphenylphosphine)palladium and potassium carbonate were added to 120 mL of a mixed solvent of toluene, ethanol and water with a volume ratio of 10:10:8 in a molar ratio of 5:6.25:0.25:25. Nitrogen gas was introduced and the mixture was heated at 110 °C for 1 day. After the reaction was completed, the mixture was processed to obtain compound (13). Equation (13); Compound (13), 4,4',4''-phosphotriol and triphenylphosphine were added to 10 mL of anhydrous tetrahydrofuran in a molar ratio of 4.2:1:4. Nitrogen gas was introduced and 0.9 mL of azodicarboxylic acid diisopropionate was added dropwise at 0 °C. The mixture was heated at 40 °C for 2 days. After the reaction was completed, the mixture was processed to obtain compound (14). Equation (14); Mix 0.5 g of compound (14) with 10 mL of 4 M HCl aqueous solution, purge with nitrogen gas, heat at 30 °C for 2 days, process after reaction to obtain compound (15), which is the tridentate organic ligand; Equation (15); K2. Weigh 187.03 mg (0.10 mmol) of tridentate organic ligand, 275.08 mg (0.12 mmol) of Zn(NTf2) and 16.09 mg (0.11 mmol) of tris(2-aminoethyl) and transfer them to a reaction flask containing 60 mL of acetonitrile solvent. Replace the nitrogen (or argon) gas three times under reduced pressure. Then heat the reaction at 80 °C for 25 hours. Filter the reaction solution through a 0.22 µm PTFE filter membrane. Transfer the filtrate to a crystallization container and slowly diffuse diethyl ether (diffusion rate: 1 mL / h). After 7 days, collect the colorless prismatic crystals, wash them three times with diethyl ether, and dry them under vacuum (40 °C, 10-2 bar) to obtain the compound C3-L4-Zn cage of formula (16), which is a C3 symmetrical cone-shaped mononuclear metal-organic cage compound. Equation (16).

[0046] Example 6 A C3-symmetric, cone-shaped, mononuclear, organometallic cage-like compound containing a Zn group. 2+ Nodes, and with Zn 2+ A combination of a tridentate organic ligand with tris(2-aminoethyl) via node coordination; the tridentate organic ligand is composed of three branched structures of tris(triphenol) connected by an ether chain; The outrigger structure is ; The preparation method of C3-symmetric cone-shaped mononuclear metal-organic cage compounds includes the following steps: K1. Obtaining tridentate organic ligands ( C 3. Symmetrical ligand L5), its preparation method is as follows: Compound (13), triphenylphenol and triphenylphosphine were added to 10 mL of anhydrous tetrahydrofuran in a molar ratio of 4.2:1:4. Nitrogen gas was introduced and 0.9 mL of diisopropionate azodicarboxylate was added dropwise at 0 °C. The mixture was heated at 40 °C for 2 days. After the reaction was completed, the mixture was processed to obtain compound (17). Equation (17); 0.5 g of compound (17) was mixed with 10 mL of 4 M HCl aqueous solution, nitrogen gas was introduced, and the mixture was heated at 30 °C for 2 days. After the reaction was completed, compound (18) was obtained, which is the tridentate organic ligand. Equation (18); K2. Weigh 170.02 mg (0.10 mmol) of tridentate organic ligand, 275.08 mg (0.12 mmol) of Zn(NTf2) and 16.09 mg (0.11 mmol) of tris(2-aminoethyl) and transfer them to a reaction flask containing 60 mL of acetonitrile solvent. Replace the nitrogen (or argon) gas three times under reduced pressure. Then heat the reaction at 80 °C for 25 hours. Filter the reaction solution through a 0.22 µm PTFE filter membrane. Transfer the filtrate to a crystallization container and slowly diffuse diethyl ether (diffusion rate: 1 mL / h). After 7 days, collect the colorless prismatic crystals, wash them three times with diethyl ether, and dry them under vacuum (40 °C, 10-2 bar) to obtain the compound C3-L5-Zn cage of formula (19), which is a C3 symmetrical cone-shaped mononuclear metal-organic cage compound. Equation (19).

[0047] Example 7 A C3-symmetric, cone-shaped, mononuclear, organometallic cage-like compound containing a Zn group. 2+ Nodes, and with Zn 2+ A combination of a tridentate organic ligand with tris(2-aminoethyl) via node coordination; the tridentate organic ligand is composed of three branched structures of tris(triphenol) connected by an ether chain; The outrigger structure is ; The preparation method of C3-symmetric cone-shaped mononuclear organometallic cage compounds includes the following steps: K1. Obtaining tridentate organic ligands ( C 3. Symmetrical ligand L6), its preparation method is as follows: Compound (13), 4,4',4''-(1,3,5-triazine-2,4,6-trimethylene)triol and triphenylphosphine were added to 10 mL of anhydrous tetrahydrofuran in a molar ratio of 4.2:1:4. Nitrogen gas was introduced, and 0.9 mL of azodicarboxylic acid diisopropionate was added dropwise at 0 °C. The mixture was heated at 40 °C for 2 days. After the reaction was completed, the mixture was processed to obtain compound (20). Equation (20); Mix 0.5 g of compound (20) with 10 mL of 4 M HCl aqueous solution, purge with nitrogen gas, heat at 30 °C for 2 days, and process after the reaction to obtain compound (21), which is the tridentate organic ligand. Equation (21); K2. Weigh 170.02 mg (0.10 mmol) of tridentate organic ligand, 275.08 mg (0.12 mmol) of Zn(NTf2) and 16.09 mg (0.11 mmol) of tris(2-aminoethyl) and transfer them to a reaction flask containing 60 mL of acetonitrile solvent. Replace the nitrogen (or argon) gas three times under reduced pressure. Then heat the reaction at 80 °C for 25 hours. Filter the reaction solution through a 0.22 µm PTFE filter membrane. Transfer the filtrate to a crystallization container and slowly diffuse diethyl ether (diffusion rate: 1 mL / h). After 7 days, collect colorless prismatic crystals, wash them three times with diethyl ether, and dry them under vacuum (40 °C, 10-2 bar) to obtain the compound C3-L6-Zn cage of formula (22), which is a C3 symmetrical cone-shaped mononuclear metal-organic cage compound. Equation (22).

[0048] Testing and Evaluation The C3-symmetric cone-shaped mononuclear organometallic cage compound (1.75 mg, 1.00 μmol) obtained in Example 1 was dissolved in acetonitrile, followed by the addition of an acetonitrile solution containing tetra-n-butylammonium chloride (0.56 mg, 2.00 μmol). After shaking to homogenize, the mixture was heated at 45°C for 30 minutes. Figure 3 As shown, after NMR (nuclear magnetic resonance) analysis, the solution was found to contain... C 3-L1-Zn 1 HNMR spectrum and without any added substances C 3-L1-Zn 1 The H NMR spectrum showed significant changes. And towards the above... C Adding different equivalents of chloride ions (0.25 equiv., 0.50 equiv., 0.75 equiv., 1.00 equiv., 2.00 equiv., 4.00 equiv., 6.00 equiv., 8.00 equiv., 10.00 equiv.) to a 3-L1-Zn solution also resulted in... 1 The HNMR spectrum showed certain changes; the higher the concentration of chloride ions, the more pronounced the changes. Therefore, the HNMR spectrum obtained in Example 1... CThe 3-L1-Zn cage has the ability to identify and detect chloride ions. Furthermore, replacing chloride ions with fluoride ions, bromide ions, iodide ions, nitrate ions, sulfate ions, trifluoromethanesulfonate ions, and trifluoromethanesulfonylimide ions can also lead to… C 3-L1-Zn solution 1 The H NMR spectrum changed, therefore the H NMR spectrum obtained in Example 1 C The 3-L1-Zn cage also has the ability to identify and detect the above-mentioned anions.

[0049] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A C3-symmetric, cone-shaped, mononuclear, metal-organic cage-like compound, characterized in that, It comprises a metal cation node and a combination of a tridentate organic ligand and an organic amine coordinated to the metal cation node; the tridentate organic ligand is composed of a C3-symmetric bottom central structure connected by three branch structures via ether chains; the organic amine is an aromatic amine and / or an aliphatic amine; the C3-symmetric bottom central structure is a C3-symmetric polyphenol; the branch structures contain benzyl and ether chain groups, and are terminated by pyridine-2-carboxaldehyde groups.

2. The C3-symmetric cone-shaped mononuclear metal-organic cage compound according to claim 1, characterized in that, The arm structure is selected from formula (II): Equation (Ⅱ), where n is a natural number.

3. The C3-symmetric cone-shaped mononuclear metal-organic cage compound according to claim 1, characterized in that, The symmetrical bottom center structure of C3 is selected from formula (Ⅲ): Formula (III).

4. The C3-symmetric cone-shaped mononuclear metal-organic cage compound according to claim 1, characterized in that, The fatty amine is selected from one or more of tris(2-aminoethyl)amine and tris(3-aminopropyl)amine; the aromatic amine is selected from one or more of aniline, methylaniline, haloaniline, methoxyaniline, phenylaniline, and benzylaniline.

5. The C3-symmetric cone-shaped mononuclear metal-organic cage compound according to claim 1, characterized in that, The metal cation is selected from one of Cr(II), Mn(II), Fe(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II), Rh(II) / (III), and Ru(II) / (III).

6. The C3-symmetric cone-shaped mononuclear metal-organic cage compound according to claim 1, characterized in that, The three arms have the same structure.

7. A method for preparing a C3-symmetric cone-shaped mononuclear metal-organic cage compound as described in any one of claims 1-6, characterized in that, Includes the following steps: Obtaining tridentate organic ligands; A tridentate organic ligand, an organic amine, and a metal salt are mixed in an organic solvent and subjected to a coordination self-assembly reaction to obtain a C3-symmetric cone-shaped mononuclear metal-organic cage compound.

8. The preparation method according to claim 7, characterized in that, The preparation method of the tridentate organic ligand is as follows: Obtain the intermediate body of the extended arm; Using extended-arm intermediates and C3-symmetric polyphenols as raw materials, etherification reactions were carried out in organic solvents under the conditions of azodicarbonate diester, phosphine reagent and inert atmosphere to obtain tridentate ligand precursors; The tridentate ligand precursor was subjected to hydrolysis protection under acidic conditions to obtain the tridentate organic ligand.

9. A crystalline material, characterized in that, It is prepared from a C3-symmetric cone-shaped mononuclear metal-organic cage compound as described in any one of claims 1-6 according to a crystal culture template.

10. The application of a symmetrical cone-shaped mononuclear metal-organic cage compound as described in any one of claims 1-6 in the field of anion detection.

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