Platinum-based coordination assemblies with controllable cavity structures and methods of making the same

Abstract

The application belongs to the technical field of supramolecular chemistry, and particularly relates to a platinum-based coordination assembly with a controllable cavity structure and a preparation method thereof. The platinum-based coordination assembly is formed by self-assembly through coordination bonds, with a tetradentate pyridine ligand as a structural guiding core, sodium carboxylate ligands as cavity regulating units, and an organic metal platinum (II) ligand as a metal node. The tetradentate pyridine ligand is a tetrapyridyl ligand based on 9,10-bis(diphenylmethylene)-9,10-dihydroanthracene. The organic metal platinum (II) ligand is cis-bis(triethylphosphine)bis(trifluoromethylsulfonate) platinum (II). The sodium carboxylate ligand is a bidentate sodium carboxylate ligand or a tetradentate sodium carboxylate ligand. The coordination assembly provided by the application can realize fine regulation of the configuration and cavity size of the final assembly by only changing one organic ligand, significantly reducing the complexity of synthesis and screening, and effectively breaking through the limitations of dynamic regulation and precise size control in traditional methods.

Description

Technical Field

[0001] This invention belongs to the field of supramolecular chemistry technology, specifically relating to a platinum-based coordination assembly with a controllable cavity structure and its preparation method. Background Technology

[0002] Metal coordination assemblies are supramolecular structures formed by the self-assembly of metal ions and organic ligands through coordination bonds. They have attracted widespread attention due to their potential applications in catalysis, molecular recognition, sensing, drug delivery, and functional materials. Among them, assemblies with specific geometries and cavity structures can mimic the functional cavities of biological enzymes, achieving highly selective host-guest chemical behavior, and have become a research hotspot in this field.

[0003] In supramolecular chemistry, existing strategies for constructing coordination assemblies with controllable cavities mainly rely on the following: First, designing and synthesizing a series of rigid ligands with different structures and lengths to directly control the cavity size. However, this process usually involves cumbersome organic synthesis, multi-step purification, and complex characterization, resulting in long development cycles, high costs, and low efficiency. Furthermore, due to the rigid structure of the ligands themselves and the thermodynamic characteristics of the assembly process, the obtained cavity structures are often discretely distributed and cannot be systematically regulated, making it difficult to achieve precise matching with guest molecules of specific sizes, severely limiting the predictability and functional customization of host-guest chemical properties. Second, indirectly regulating the cavity environment by changing metal nodes, post-synthetic modification, or template induction. However, these methods either cannot accurately predict the final structure or cannot substantially change the physical size of the cavity. Therefore, no universally applicable scheme that is simple to synthesize, efficient, and allows for precise control of cavity size has been achieved in the current technologies, severely limiting its application in functional scenarios requiring high-precision host-guest matching. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a platinum-based coordination assembly with a controllable cavity structure and its preparation method.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A platinum-based coordination assembly with a controllable cavity structure is prepared by self-assembly of coordination bonds using a tetradentate pyridine ligand as the structure guiding core, a sodium carboxylate ligand as the cavity control unit, and an organometallic platinum(II) ligand as the metal node.

[0006] The tetradentate pyridine ligand is a tetrapyridyl derivative based on 9,10-bis(diphenylmethylene)-9,10-dihydroanthracene (BDPM-DHA), preferably 9,10-bis(bis(4-(pyridin-4-yl)phenyl)methylene)-9,10-dihydroanthracene. This ligand is derived from a previously reported literature (Qian Feng, et al. 9,10-Bis(diphenylmethylene)-9,10-dihydroanthracene-based metal-organic assemblies with aggregation-induced emission for multiple sensing. Chin. Chem. Lett., 2023, 34, 108439), and possesses a unique "butterfly" configuration. Its anthracene core can dynamically flip, and the outer benzene ring can rotate freely, endowing the ligand with significant structural flexibility and conformational adaptability. When performing multi-component self-assembly with sodium carboxylate ligands of different lengths and organometallic platinum (II) ligands, the pyridine ligand can undergo conformational adaptive adjustment according to the spatial size and coordination requirements of the carboxylate ligand. By dynamically flipping and rotating to match different coordination geometries and spatial environments, it can guide the assembly to form coordination assemblies with different configurations and cavity sizes.

[0007] The sodium carboxylate ligand is either a bidentate sodium carboxylate ligand or a tetradentate sodium carboxylate ligand. The bidentate sodium carboxylate ligand is sodium terephthalate, and the tetradentate sodium carboxylate ligand is [1,1':4',1'']terphenyl-3,3'',5,5''-tetracarboxylate sodium or 1,1':4',1'':4'',1'''-tetraphenyl-3,3''',5,5'''-tetracarboxylate sodium. All of the above sodium carboxylates can be conveniently and efficiently prepared from their corresponding carboxylic acids (commercially available raw materials) through a simple acid-base neutralization reaction.

[0008] The organometallic platinum(II) ligand is cis-bis(triethylphosphine)bis(trifluoromethanesulfonic acid)platinum(II) with a tetragonal planar configuration.

[0009] The structural formula of the tetradentate pyridine ligand is as follows: .

[0010] The structural formula of the organometallic platinum(II) ligand is as follows: Wherein, -OTf is trifluoromethanesulfonate ion and -PEt3 is triethylphosphine group.

[0011] The structural formula of sodium terephthalic acid is: .

[0012] The structural formula of sodium terphenyl-3,3'',5,5''-tetracarboxylate is: .

[0013] The structural formula of sodium 1,1':4',1'':4'',1'''-tetraphenyl-3,3''',5,5'''-tetracarboxylate is: .

[0014] Further, the molar ratio of the tetradentate pyridine ligand, the sodium carboxylate ligand, and the organometallic platinum(II) ligand is 1:1 to 2:4. Preferably, the molar ratio of the tetradentate pyridine ligand, the bidentate sodium carboxylate ligand, and the organometallic platinum(II) ligand is 1:2:4; and the molar ratio of the tetradentate pyridine ligand, the tetradentate sodium carboxylate ligand, and the organometallic platinum(II) ligand is 1:1:4. Deviations from these ratios make it difficult to purify target assemblies with specific configurations and cavities.

[0015] Divalent platinum metal centers, with their well-defined and stable tetragonal planar coordination configuration, are ideal nodes for constructing directed supramolecular assemblies. Currently, numerous studies have successfully constructed various two-dimensional or three-dimensional supramolecular structures based on platinum nodes and various nitrogen-containing and carboxylate-containing ligands. However, existing techniques largely focus on obtaining thermodynamically stable single configurations using rigid ligands, which has significant limitations in terms of flexibility and diversity in structure control. Insufficient precision in configuration control: Traditional assembly synthesis strategies often rely on the inherent geometry of the ligands themselves; once the ligands are determined, the resulting assembly configuration is essentially fixed. Methods that control the final assembly structure by changing the ligands are not only labor-intensive and time-consuming, but also difficult to achieve fine-tuning of cavity size and shape. Lack of forward-looking design methods: Experimental studies often employ a "trial and error" approach, i.e., synthesis followed by characterization. This lack of prior theoretical guidance and precise prediction of the thermodynamics and kinetics of the assembly process leads to low efficiency in the controllable preparation of target assemblies and makes it difficult to customize assemblies with specific cavity structures as needed. The sodium carboxylate ligands of this invention were obtained by optimizing the assembly structure configuration using Materials Studio software, followed by geometric optimization, annealing calculations, and selection. This invention develops a novel strategy for precisely pre-designing and efficiently controlling the assembly configuration. Utilizing computational chemistry-assisted rational design methods, the assembly structure configuration is optimized using Materials Studio software. By selecting suitable sodium carboxylate ligands and constructing a library of multidentate ligands of different sizes, a series of platinum-based coordination assemblies with tunable cavity structures are provided. This invention solves the problem of difficulty in precisely controlling the configuration of existing assemblies, achieving simple and efficient control over the cavity size and shape of the assembly.

[0016] This invention also provides a method for preparing a platinum-based coordination assembly with a controllable cavity structure, comprising the following steps: Tetradentate pyridine ligand, sodium carboxylate ligand, and organometallic platinum(II) ligand were reacted in a mixed solvent by stirring to obtain an assembly solution; the assembly solution was deliquescent, redissolved in acetonitrile, and filtered to obtain a crude product solution; the crude product solution was recrystallized with diethyl ether to obtain a platinum-based coordination assembly with a controllable cavity structure.

[0017] Furthermore, in the preparation of the assembly solution, when the sodium carboxylate ligand is a bidentate sodium carboxylate ligand, the tetradentate pyridine ligand is reacted with the organometallic platinum(II) ligand for 3 to 5 hours, and then the bidentate sodium carboxylate ligand is added and reacted for 6 to 8 hours.

[0018] Furthermore, in the preparation of the assembly solution, when the sodium carboxylate ligand is a tetradentate sodium carboxylate ligand, the tetradentate sodium carboxylate ligand is first reacted with the organometallic platinum(II) ligand for 3 to 5 hours, and then the tetradentate pyridine ligand is added and reacted for 6 to 8 hours.

[0019] In the preparation of the above platinum-based coordination assemblies, if the order of addition of pyridine and carboxylic acid ligands is changed, more impurity assemblies will appear. Since the properties of the impurity assemblies are similar to those of the target assembly, they are difficult to purify, which will reduce the purity of the target product and restrict the acquisition of high-purity platinum-based coordination assembly materials.

[0020] Furthermore, the mixed solvent consists of acetonitrile and water.

[0021] Furthermore, the temperature of the stirred reaction is 50℃~70℃. The reaction needs to be carried out at a suitable temperature. Too high a temperature will trigger side reactions, reducing the purity and yield of the target assembly; too low a temperature will significantly slow down the coordination reaction rate, prolong the reaction time, and lead to incomplete reaction, which will also reduce the yield and purity of the target assembly.

[0022] Furthermore, the liquid was removed by blowing it dry in a metal bath with a nitrogen stream. Filtration was performed using glass fiber filtration. The recrystallization process of the crude product solution with diethyl ether was repeated at least twice, and drying was carried out under vacuum conditions at room temperature.

[0023] Compared with the prior art, the present invention has the following beneficial effects: This invention utilizes a tetradentate pyridine ligand as the structure-directing core, a sodium carboxylate ligand as the cavity control unit, and an organometallic platinum(II) ligand as the metal node to prepare platinum-based coordination assemblies through coordination bond self-assembly. These coordination assemblies rely on a butterfly-shaped tetradentate pyridine ligand with a dynamic conformation and a metal center with a specific coordination configuration. During multi-component self-assembly with sodium carboxylate ligands of different lengths, the tetradentate pyridine ligand can adaptively adjust its conformation according to the spatial size and coordination requirements of the sodium carboxylate ligand. Through dynamic flipping and rotation matching different coordination geometries and spatial environments, it guides the assemblies to form coordination assemblies with different configurations and cavity sizes. This invention discloses a universal strategy that allows for precise control of the final assembly configuration and cavity size by changing only one organic ligand. The synthesis method is simple and efficient, effectively overcoming the limitations of traditional methods in achieving dynamic adjustment and precise size control. It provides a general strategy for constructing active cavities with specific recognition, catalysis, or sensing functions on demand at the molecular scale.

[0024] This invention discloses a method for preparing platinum-based coordination assemblies with controllable cavity structures. During the assembly design phase, Materials Studio software was used to simulate and optimize the assembly structure. The simulation process included geometric optimization and annealing to determine the most stable configuration of the assembly. Based on the optimal configuration, suitable sodium carboxylate ligands were then screened, thereby achieving precise assembly design. This simulation process transforms traditional trial-and-error experiments into rational design, significantly improving R&D efficiency and reducing time and costs.

[0025] This invention develops a stepwise one-pot assembly method that significantly improves the purity of platinum-based multi-component butterfly-shaped coordination assemblies. In traditional one-pot assembly processes, due to the complexity of kinetic competition and thermodynamic control, various mismatched assembly impurities often exist in the product. These impurities have properties similar to the target product and are difficult to separate effectively using conventional methods (such as recrystallization), severely limiting the acquisition of high-purity materials. This method introduces reactants stepwise, first allowing a portion of the metal ions to react with structure-directed pyridine ligands. After the key intermediate is stably formed, sodium carboxylate ligands of different lengths are then introduced. By adding reactants stepwise and controlling the timing, statistically chaotic pairing of all ligands and metal ions is avoided in the initial stage, eliminating the possibility of most mismatches from the outset. The entire assembly process becomes a coordinated and ordered process, ultimately forming target coordination assemblies with specific configurations and cavity sizes with high yield and high selectivity. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 Flowcharts showing the preparation of platinum-based coordination assemblies with different configurations.

[0028] Figure 2 The platinum-based coordination assembly obtained in Example 1 1 H NMR spectrum.

[0029] Figure 3 The platinum-based coordination assembly obtained in Example 1 31 P NMR spectrum.

[0030] Figure 4 This is the mass spectrum of the platinum-based coordination assembly obtained in Example 1.

[0031] Figure 5 The distribution of observed and theoretical values ​​of the trivalent characteristic peaks of the platinum-based coordination assembly obtained in Example 1.

[0032] Figure 6 This is a simulated structural diagram of the platinum-based coordination assembly obtained in Example 1.

[0033] Figure 7 The platinum-based coordination assembly obtained in Example 2 1 H NMR spectrum.

[0034] Figure 8 The platinum-based coordination assembly obtained in Example 2 31 P NMR spectrum.

[0035] Figure 9 This is the mass spectrum of the platinum-based coordination assembly obtained in Example 2.

[0036] Figure 10 The distribution of observed and theoretical values ​​of the pentavalent characteristic peak of the platinum-based coordination assembly obtained in Example 2.

[0037] Figure 11 This is a simulated structural diagram of the platinum-based coordination assembly obtained in Example 2.

[0038] Figure 12 The platinum-based coordination assembly obtained in Example 3 1 H NMR spectrum.

[0039] Figure 13 The platinum-based coordination assembly obtained in Example 331 P NMR spectrum.

[0040] Figure 14 This is the mass spectrum of the platinum-based coordination assembly obtained in Example 3.

[0041] Figure 15 The distribution of observed and theoretical values ​​of the trivalent characteristic peak of the platinum-based coordination assembly obtained in Example 3.

[0042] Figure 16 This is a simulated structural diagram of the platinum-based coordination assembly obtained in Example 3. Detailed Implementation

[0043] The specific embodiments of the present invention are described in detail below, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Unless otherwise specified, the experimental methods described in the embodiments of the present invention are conventional methods, and the materials and reagents used in the following embodiments are commercially available unless otherwise specified.

[0044] This invention discloses a platinum-based coordination assembly with a controllable cavity structure based on BDPM-DHA and its preparation method. A schematic diagram of its self-assembly is shown below. Figure 1 As shown, this series of platinum-based coordination assemblies are thermodynamically stable products formed by the self-assembly of tetradentate pyridine ligands, bidentate / tetradentate sodium carboxylate ligands, and organometallic platinum(II) ligands in a mixed solution. These coordination assemblies rely on butterfly-shaped organic ligands with dynamic conformations and metal centers with specific coordination configurations. During multi-component self-assembly with sodium carboxylate ligands of different lengths, the pyridine ligands can undergo conformational adaptive adjustment according to the spatial size and coordination requirements of the sodium carboxylate ligands. Through dynamic flipping and rotation to match different coordination geometries and spatial environments, the assemblies are guided to form coordination assemblies with different configurations and cavity sizes.

[0045] The specific experimental steps are as follows: The first step is the reaction process of the platinum-based coordination assembly.

[0046] For the platinum-based coordination assembly formed by sodium bidentate carboxylate, the tetradentate pyridyl ligand, sodium bidentate carboxylate ligand, and organometallic platinum(II) ligand were precisely weighed using a precision balance at a molar ratio of 1:2:4. First, the tetradentate pyridyl ligand and organometallic platinum(II) ligand were dispersed in acetonitrile and sonicated until completely dissolved. Then, the mixture was reacted in a metal bath at 50℃–70℃ for 3–5 hours to obtain a mixed solution. Next, the weighed sodium bidentate carboxylate ligand was dissolved in distilled water and added dropwise to the mixed solution, and the reaction was continued for 6–8 hours.

[0047] For the platinum-based coordination assembly formed by sodium tetradentate carboxylate, the components are weighed at a molar ratio of 1:1:4, and the sodium tetradentate carboxylate ligand and the organometallic platinum(II) ligand are reacted in a mixed solvent of acetonitrile and distilled water for 3–5 hours to obtain a mixed solution. Then, the sodium tetradentate carboxylate ligand is added to the mixed solution, and the reaction continues for 6–8 hours. The remaining procedures remain unchanged.

[0048] Step 2: Purification process of platinum-based coordination assemblies.

[0049] The reaction mixture obtained in the first step was dried in a metal bath under a nitrogen stream. Acetonitrile was then added to dissolve the residual solid, resulting in a turbid mixed solution. This turbid solution was filtered through a glass fiber filter to obtain a clear solution. Diethyl ether was added dropwise to the clear solution for recrystallization, during which flocculent solids were observed to gradually precipitate. The supernatant was then discarded by centrifugation, and the solution was vacuum dried at room temperature for 4–6 hours to obtain the platinum-based coordination assembly. Repeating the recrystallization process 2–3 times ensures a pure target product and reduces the incorporation of byproduct assemblies.

[0050] The present invention will now be described in detail with reference to specific embodiments and accompanying drawings: Example 1: Preparation method of platinum-based coordination assemblies based on BDPM-DHA The sodium bidentate ligand structure used in this embodiment is shown in the following formula: ; Step 1: The reaction process of platinum-based coordination assemblies.

[0051] Precisely weigh the tetradentate pyridyl ligand 9,10-bis(bis(4-(pyridin-4-yl)phenyl)methylene)-9,10-dihydroanthracene (5.00 mg, 6.12 μmol, 1 equiv) and the organometallic platinum(II) ligand cis-bis(triethylphosphine)bis(trifluoromethanesulfonic acid)platinum(II) (17.86 mg, 24.48 μmol, 4 equiv) in 8 mL of acetonitrile. Sonicate until completely dissolved, then react in a metal bath at 60 °C for 3 h to obtain a mixed solution. Precisely weigh the disodium bidentate carboxylate ligand sodium terephthalate (2.57 mg, 12.24 μmol, 2 equiv) in 2 mL of distilled water using a precision balance. Add the disodium bidentate carboxylate ligand dropwise to the mixed solution over 2 min. Continue the reaction in a metal bath at 60 °C for 6 h.

[0052] Step 2: Purification process of platinum-based coordination assemblies.

[0053] The reaction mixture obtained in the first step was dried in a metal bath at 60°C with a nitrogen stream to obtain a residual solid. Then, 2 mL of acetonitrile was added to dissolve the residual solid, and the solution was filtered through glass fiber to obtain a clear solution. 4 mL of diethyl ether was added dropwise to the clear solution, and flocculent solids were observed to gradually precipitate out. After centrifugation, the supernatant was discarded to obtain a pale yellow solid. The above process of dissolution, filtration, recrystallization, and centrifugation was repeated twice. Then, the mixture was vacuum dried at room temperature for 6 hours to obtain 16.34 mg of the assembly, with a yield of 77%.

[0054] Figures 2-6 The platinum-based coordination assemblies prepared in Example 1 are respectively 1 H NMR spectrum, 31 P NMR spectrum, mass spectrum, distribution of observed and theoretical values ​​of trivalent characteristic peaks, and simulated structure diagram. 1 The chemical shifts of each peak in the H NMR spectrum correspond one-to-one with the positions of hydrogen atoms in the platinum-based coordination assembly, and the ratio of the integral areas of each peak matches the ratio of the number of protons at the corresponding positions in the platinum-based coordination assembly. This indicates that the assembly was successfully synthesized with a pre-defined, highly symmetrical, and regular structure, and that the product is pure and structurally stable. 31 In the P NMR spectrum, the phosphorus peak splits into two sets of doublets of equal intensity. This is because the N and O atoms on the pyridinyl and carboxylic acid groups are coordinated with platinum atoms, resulting in the phosphorus atom being in two different chemical environments. This result confirms that the coordination assembly forms a discrete, charge-separated, three-dimensional bicyclic butterfly structure. In the mass spectrum, the stoichiometry of the ligands in the assembly confirms its chemical composition. With the counterion OTf... – The absence of the positive charge resulted in a series of characteristic peaks in the assembly, and the peak distribution of the measured trivalent characteristic peaks closely matched the theoretical simulation values. The simulated structural diagram visually demonstrated the rationality of the formation of the three-dimensional double-ring structure. These results collectively indicate the successful preparation of the platinum-based coordination assembly.

[0055] Example 2: Preparation method of platinum-based coordination assemblies based on BDPM-DHA The tetradentate sodium carboxylate ligand structure used in this example is shown in the following formula: ; Step 1: The reaction process of platinum-based coordination assemblies.

[0056] The tetradentate sodium carboxylate ligand [1,1':4',1'']terphenyl-3,3'',5,5''-tetracarboxylate sodium (3.02 mg, 6.12 μmol, 1 equiv) and the organometallic platinum(II) ligand cis-bis(triethylphosphine)bis(trifluoromethanesulfonic acid)platinum(II) (17.86 mg, 24.48 μmol, 4 equiv) were accurately weighed using a precision balance (1 / 100,000) and dispersed in a mixed solvent of 8 mL acetonitrile and 2 mL distilled water. The solution was sonicated until completely dissolved, and then reacted in a metal bath at 50 °C for 4 h to obtain a mixed solution. The tetradentate pyridine ligand 9,10-bis(bis(4-(pyridin-4-yl)phenyl)methylene)-9,10-dihydroanthracene (5.00 mg, 6.12 μmol, 1 equiv) was accurately weighed using a precision balance (1 / 100,000) and added to the mixed solution. The reaction was then continued in a metal bath at 50 °C for 7 h.

[0057] Step 2: Purification of the coordination assemblies.

[0058] The reaction mixture obtained in the first step was dried in a metal bath at 50°C with a nitrogen stream to obtain a residual solid. Then, 2 mL of acetonitrile solvent was added to dissolve the solid, and the solution was filtered through glass fiber to obtain a clear solution. 4 mL of diethyl ether was added dropwise to the clear solution, and flocculent solids were observed to gradually precipitate out. After centrifugation, the supernatant was discarded to obtain a pale yellow solid. The above dissolution, filtration, recrystallization, and centrifugation process was repeated 3 times. Then, the mixture was vacuum dried at room temperature for 6 hours to obtain 14.35 mg of the assembly, with a yield of 66%.

[0059] Figures 7-11 The platinum-based coordination assemblies prepared in Example 2 are respectively 1 H NMR spectrum, 31 P NMR spectrum, mass spectrum, distribution of observed and theoretical values ​​of pentavalent characteristic peaks, and simulated structure diagram. 1 The chemical shifts of each peak in the 1H NMR spectrum correspond one-to-one with the positions of hydrogen atoms in the assembly, and the ratio of the integrated areas of each peak matches the ratio of the number of protons at the corresponding positions in the assembly. α-Pyridine hydrogen atoms (H a ) and β-pyridyl hydrogen atom (H b The peak shape splits because the protons are located inside and outside the assembly, respectively. These results indicate that the assembly was successfully synthesized with a pre-defined, highly symmetrical, and regular structure, and the product is pure and structurally stable. 31In the P NMR spectrum, the phosphorus peak splits into two sets of doublets of equal intensity. This is because the N and O atoms on the pyridinyl and carboxylic acid groups are coordinated with platinum atoms, resulting in the phosphorus atom being in two different chemical environments. This result confirms that the coordination assembly forms a cage-like structure with discrete structure and charge separation. In the mass spectrum, the stoichiometry of the ligands in the assembly confirms the chemical composition of the assembly. With the counterion OTf... – After the removal of the positive charge, the assembly exhibited a series of characteristic peaks with positive charges, and the peak distribution of the measured pentavalent characteristic peaks was in excellent agreement with the peak distribution of the theoretical simulation. The simulated structural diagram visually demonstrated the rationality of the formation of the large cavity cage structure. All these results collectively indicate the successful preparation of the platinum-based coordination assembly.

[0060] Example 3: Preparation method of platinum-based coordination assemblies based on BDPM-DHA The tetradentate sodium carboxylate ligand structure used in this example is shown in the following formula: ; Step 1: The reaction process of platinum-based coordination assemblies.

[0061] The sodium tetradentate sodium carboxylate ligand 1,1':4',1'':4'',1'''-tetraphenyl-3,3''',5,5'''-tetracarboxylate sodium (3.49 mg, 6.12 μmol, 1 equiv) and the organometallic platinum(II) ligand cis-bis(triethylphosphine)bis(trifluoromethanesulfonic acid)platinum(II) (17.86 mg, 24.48 μmol, 4 equiv) were accurately weighed using a precision balance of 0.0001 and dispersed in a mixed solvent of 8 mL acetonitrile and 2 mL distilled water. The solution was completely dissolved by sonication and then reacted in a metal bath at 70 °C for 5 h to obtain a mixed solution. The tetradentate pyridine ligand 9,10-bis(bis(4-(pyridin-4-yl)phenyl)methylene)-9,10-dihydroanthracene (5.00 mg, 6.12 μmol, 1 equiv) was accurately weighed using a precision balance of 1 / 100,000 and added to the mixed solution. The reaction was then continued for 8 h in a metal bath at 70 °C.

[0062] Step 2: Purification process of platinum-based coordination assemblies.

[0063] The reaction mixture obtained in the first step was dried in a metal bath at 70°C with a nitrogen stream to obtain a residual solid. Then, 2 mL of acetonitrile solvent was added to dissolve the solid, and the solution was filtered through glass fiber to obtain a clear solution. 4 mL of diethyl ether was added dropwise to the clear solution, and flocculent solids were observed to gradually precipitate out. After centrifugation, the supernatant was discarded to obtain a pale yellow solid. The above process of dissolution, filtration, recrystallization, and centrifugation was repeated twice. Finally, the mixture was vacuum dried at room temperature for 4-6 hours to obtain 18.57 mg of the assembly, with a yield of 84%.

[0064] Figures 12-16 The platinum-based coordination assemblies prepared in Example 3 are respectively platinum-based coordination assemblies. 1 H NMR spectrum 31 P NMR spectrum, mass spectrum, distribution of observed and theoretical values ​​of trivalent characteristic peaks, and simulated structure diagram. 1 The chemical shifts of each peak in the 1H NMR spectrum correspond one-to-one with the positions of hydrogen atoms in the assembly, and the ratio of the integrated areas of each peak matches the ratio of the number of protons at the corresponding positions in the assembly. These results indicate that the assembly was successfully synthesized with a pre-defined, highly symmetrical, and regular structure, and that the product is pure and structurally stable. 31 In the P NMR spectrum, the phosphorus peak splits into two sets of doublets of equal intensity. This is because the N and O atoms on the pyridinyl and carboxylic acid groups are coordinated with platinum atoms, resulting in the phosphorus atom being in two different chemical environments. This result confirms that the coordination assembly forms a cage-like structure with discrete structure and charge separation. In the mass spectrum, the stoichiometry of the ligands in the assembly confirms the chemical composition of the assembly. With the counterion OTf... – After the removal of the positive charge, the assembly exhibits a series of characteristic peaks with positive charges, and the peak distribution of the measured trivalent characteristic peaks is in excellent agreement with the peak distribution of the theoretical simulation. The simulated structural diagram visually demonstrates the rationality of the formation of the small cavity cage structure. All these results collectively indicate the successful preparation of the platinum-based coordination assembly.

[0065] This invention discloses a novel class of platinum-based coordination assemblies, whose different cavity sizes directly determine the selectivity, affinity, and subsequent application range of host-guest recognition. Based on this, the platinum-based coordination assemblies provided by this invention can be used in fields such as dual-functional platforms integrating adsorption and detection. Specifically, the small-cavity structure can target volatile organic pollutants (VOCs) and phenolic compounds (such as benzene and cresol) with small molecular sizes, achieving high-capacity and high-selectivity adsorption through size-matching effects and hydrophobic interactions, making it suitable for efficient air / water purification. The large-cavity structure is specifically designed to capture large-molecule dyes (such as methyl orange and rhodamine B) and persistent organic pollutants with planar conjugated structures (such as pyrene, anthracene, and other polycyclic aromatic hydrocarbons). Its cavities can efficiently enrich and stably encapsulate these pollutants through multiple interactions (such as π-π stacking, hydrophobic interactions, and electrostatic interactions), enabling advanced wastewater treatment and resource recovery (such as dye adsorption and recovery). The inclusion effect of guest molecules can also significantly alter their photophysical properties (such as initiating fluorescence enhancement or quenching effects). This characteristic makes the adsorption process a visual sensing process. The adsorption capacity, treatment progress, and adsorbent saturation of pollutants can be monitored in real time and in situ through fluorescence spectroscopy or visual observation (if the color change is obvious), thereby realizing the intelligent function of "detection during treatment and alarm during saturation".

[0066] Although preferred embodiments of the present invention have been described, those skilled in the art, upon learning the inventive concept of the present invention, can make other changes and modifications to these embodiments, all of which fall within the scope of the present invention.

[0067] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. If such modifications and variations fall within the scope of equivalents of this invention, then this invention also intends to include these modifications and variations.

Claims

1. A platinum-based coordination assembly with a controllable cavity structure, characterized in that, The platinum-based coordination assembly is prepared by self-assembly of coordination bonds using a tetradentate pyridine ligand as the structure-directing core, a sodium carboxylate ligand as the cavity control unit, and an organometallic platinum(II) ligand as the metal node. The tetradentate pyridine ligand is 9,10-bis(bis(4-(pyridin-4-yl)phenyl)methylene)-9,10-dihydroanthracene; The sodium carboxylate ligand is a bidentate sodium carboxylate ligand or a tetradentate sodium carboxylate ligand. The bidentate sodium carboxylate ligand is sodium terephthalate, and the tetradentate sodium carboxylate ligand is [1,1':4',1'']terphenyl-3,3'',5,5''-tetracarboxylate sodium or 1,1':4',1'':4'',1'''-tetraphenyl-3,3''',5,5'''-tetracarboxylate sodium.

2. The platinum-based coordination assembly with a controllable cavity structure according to claim 1, characterized in that, The molar ratio of tetradentate pyridine ligand, sodium carboxylate ligand, and organometallic platinum(II) ligand is 1:1 to 2:

4.

3. The platinum-based coordination assembly with a controllable cavity structure according to claim 1, characterized in that, The molar ratio of tetradentate pyridine ligand, dipentate sodium carboxylate ligand, and organometallic platinum(II) ligand is 1:2:4; the molar ratio of tetradentate pyridine ligand, tetradentate sodium carboxylate ligand, and organometallic platinum(II) ligand is 1:1:

4.

4. The platinum-based coordination assembly with a controllable cavity structure according to claim 1, characterized in that, The organometallic platinum(II) ligand is cis-bis(triethylphosphine)bis(trifluoromethanesulfonic acid)platinum(II).

5. The platinum-based coordination assembly with a controllable cavity structure according to claim 1, characterized in that, Sodium carboxylate ligands were obtained by performing geometry optimization and annealing calculations using Materials Studio software.

6. A method for preparing a platinum-based coordination assembly with a controllable cavity structure as described in any one of claims 1 to 5, characterized in that, Includes the following steps: Tetradentate pyridine ligand, sodium carboxylate ligand and organometallic platinum(II) ligand were reacted in a mixed solvent by stirring to obtain an assembly solution; The assembly solution was dehydrated, redissolved in acetonitrile, and filtered to obtain a crude product solution. The crude product solution was recrystallized with diethyl ether to obtain a platinum-based coordination assembly with a controllable cavity structure.

7. The method for preparing a platinum-based coordination assembly with a controllable cavity structure according to claim 6, characterized in that, In the preparation of the assembly solution, when the sodium carboxylate ligand is a bidentate sodium carboxylate ligand, the tetradentate pyridine ligand is reacted with the organometallic platinum(II) ligand for 3 to 5 hours, and then the bidentate sodium carboxylate ligand is added and reacted for 6 to 8 hours.

8. The method for preparing a platinum-based coordination assembly with a controllable cavity structure according to claim 6, characterized in that, In the preparation of the assembly solution, when the sodium carboxylate ligand is a tetradentate sodium carboxylate ligand, the tetradentate sodium carboxylate ligand is first reacted with the organometal platinum(II) ligand for 3 to 5 hours, and then the tetradentate pyridine ligand is added and reacted for 6 to 8 hours.

9. The method for preparing a platinum-based coordination assembly with a controllable cavity structure according to claim 6, characterized in that, The mixed solvent is composed of acetonitrile and water.

10. The method for preparing a platinum-based coordination assembly with a controllable cavity structure according to claim 6, characterized in that, The temperature for the stirring reaction is 50℃~70℃.

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