Preparation methods and applications of a series of zirconium-based MOFs and their electrochromic thin films

Abstract

This invention discloses a series of zirconium-based MOFs and their preparation methods and applications for electrochromic thin films, specifically involving two MOF materials with electrochromic properties. The materials are framework materials with one-dimensional channels, one example having a unique csq topology. The metal is zirconium, and the ligand is a tetracarboxylic acid ligand containing a naphthalimide group. The one-dimensional channels include triangular channels with a diameter of 1.2 nm and hexagonal channels with a diameter of 2.7 nm. Both MOFs crystallize in the hexagonal P6 / mmm crystal system. The cell parameters of NKM-908 are a = b = 40.285, c = 23.6990, α = β = 90°, γ = 120°. The cell parameters of NKM-908-TPDC-X are a = b = 40.54, c = 23.45, α = β = 90°, γ = 120°. Here, X represents different substituents modified by the linear dicarboxylic acid ligand side chain. This application also provides the two methods for preparing the aforementioned MOF thin films, which feature simple processes, mild reaction conditions, and good reproducibility. The NKM-908 electrochromic thin film can achieve reversible color switching, changing from essentially colorless to light yellow and then to green. The NKM-908-TPDC-X thin film exhibits different color changes depending on the difference in X.

Description

Technical Field

[0001] This invention belongs to the field of electrochromic metal-organic framework materials and thin film preparation technology. Specifically, it relates to the synthesis and electrochromic application of two mesoporous zirconium-based metal-organic framework materials and thin films based on 5',5”-(1,3,6,8-tetraoxo-1,3,6,8-tetrahydrobenzo[lmn][3,8]phenanthroline-2,7-diyl)bis(2'-methoxy-[1,1'-:3',1'-triphenyl]-4,4'-dicarboxylic acid)(H4NDTB) as ligands. Background Technology

[0002] Metal-organic frameworks (MOFs) are porous crystalline materials with ordered and repeating structures, composed of metal ions / clusters and organic ligands linked periodically. Their unique advantages enable MOFs to be used in many cutting-edge fields, such as gas adsorption / separation, smart sensors, energy catalysis, and biomedicine. Among them, stimulus-responsive MOFs can change their physicochemical properties in response to external stimuli (including temperature, force, light, and electricity), making them ideal candidates for designing smart functional materials. In particular, electrochromic MOFs exhibit stable and reversible color changes when stimulated by an applied electric field, which has applications in anti-glare rearview mirrors, smart windows, optical displays, and other diverse fields. MOFs are undoubtedly recognized as one of the hottest research areas in electrochromic materials. Due to their highly ordered porous structure, the entire framework of electrochromic MOFs can directly contact electrolytes. Simultaneously, the diffusion of ions in the electrolyte and the transfer of electrons in this process can be greatly improved, thereby promoting efficient electrochromic conversion. Furthermore, the outstanding tunability and designability of MOF structures allow for a variety of electrochromic behaviors, and various redox units have been used to construct electrochromic MOFs. The team was the first to pass Zn in 2013. 2+ Electrochromic MOF films were prepared by a solvothermal reaction of ions with ligands containing naphthalenediimide (NDI). By grafting different functional groups onto the ligands, the color changes of these MOFs could be further tuned. In 2016, Two types of mesoporous electrochromic MOF-74-like MOFs films with inserted naphthalene dicarboxylate imide were constructed, exhibiting rapid and reversible color transitions. Furthermore, the design of mesoporous MOFs facilitates the separation and intercalation of ions in the electrolyte, promoting efficient electron transfer during the electrochromic process. Wang et al. developed MOF-74-type materials, introducing perylene tetracarboxylic dianhydride (PDI) units to achieve ideal electrochromic properties with excellent electrochemical stability. Besides NDI and PDI-based ligands, Farha and Hupp et al. also introduced pyrene-containing linkers to construct the NU-901 electrochromic film. Similarly, ligands characterized by viologen, triphenylamine, or triphenylamine have also been used to design MOF films with different electrochromic properties. However, currently, methods to modify the electrochromic properties of MOFs can only be achieved through de novo synthesis, resulting in time-consuming design cycles, high financial investment, and low success rates. Therefore, there is an urgent need to develop simple, rapid, and effective methods to tune the electrochromic properties of specific MOFs. Summary of the Invention

[0003] The technical problem to be solved by this invention is to overcome the shortcomings and deficiencies of existing strategies for controlling electrochromic behavior, such as difficulty, long cycle, high capital investment and low success rate, and to provide a simple, efficient and low cost strategy for controlling electrochromic behavior.

[0004] A second objective of this invention is to provide a method for synthesizing the aforementioned metal-organic framework material and thin film;

[0005] A third objective of this invention is to provide the application of the aforementioned metal-organic framework materials in electrochromism;

[0006] This invention utilizes zirconium metal as a node and 5',5”-(1,3,6,8-tetraoxo-1,3,6,8-tetrahydrobenzo[lmn][3,8]phenanthroline-2,7-diyl)bis(2'-methoxy-[1,1'-:3',1'-triphenyl]-4,4'-dicarboxylic acid)(H4NDTB) as an organic ligand, with N,N-dimethylformamide as the solvent, to synthesize a metal-organic framework material with a CSQ topology and one-dimensional mesoporous channels using a solvothermal method. Furthermore, post-synthetic modifications were performed on the above material to synthesize another metal-organic framework material containing different redox centers.

[0007] Based on the above objectives, the technical solution adopted by the present invention is as follows:

[0008] Two mesoporous zirconium-based metal-organic framework materials are characterized by using Zr as the metal and 5',5”-(1,3,6,8-tetraoxo-1,3,6,8-tetrahydrobenzo[lmn][3,8]phenanthroline-2,7-diyl)bis(2'-methoxy-[1,1'-:3',1'-triphenyl]-4,4'-dicarboxylic acid), abbreviated as H4NDTB, as the ligand. All the carboxylic acid groups in the ligand participate in coordination with the zirconium metal to form a metal-organic framework material. The framework structure is a three-dimensional network structure containing one-dimensional mesoporous channels.

[0009] The two mesoporous zirconium-based metal-organic framework materials have hexagonal crystal lattice characteristics with space group P6 / mmm; the cell parameters of the materials are a=b=40.285, c=23.6990, α=β=90°, γ=120° and a=b=40.54, c=23.45, α=β=90°, γ=120°, respectively; the pore types of the two materials are 1.2 nm triangular micropores and 2.7 nm one-dimensional hexagonal mesoporous channels.

[0010] The method for synthesizing the two mesoporous zirconium-based metal-organic framework materials and their thin films is characterized by comprising the following steps:

[0011] (1) Preparation of 2,6-dibromo-4-nitrophenol:

[0012] 4-Nitrophenol, 4-methylbenzenesulfonic acid, potassium bromide and NBS were dissolved in water. The mixture was stirred at 40°C for 2 hours. The reaction was cooled to room temperature, filtered to obtain a solid, washed with sodium metabisulfite aqueous solution, and dried to obtain the product.

[0013] (2) Preparation of 1,3-dibromo-2-methoxy-5-nitrobenzene:

[0014] Compound 2,6-dibromo-4-nitrophenol, methyl iodine, and K2CO3 were dissolved in acetonitrile. The reaction mixture was heated under reflux for 18 hours and then cooled to room temperature. Acetonitrile was removed by rotary evaporation. The resulting mixture was poured into water and extracted with dichloromethane. Before removing the solvent again using a rotary evaporator, the combined organic layers were dried on anhydrous MgSO4. The product was purified by column chromatography on silica gel using hexane as eluent. After evaporation of the fraction containing the product, a white powdery compound was obtained as the product.

[0015] (3) Preparation of 3,5-dibromo-4-methoxyaniline:

[0016] Iron and NH4Cl were added to a 100 mL round-bottom flask, followed by H2O. The mixture was stirred and refluxed in an oil bath at 100 °C for 30 minutes. Then, 1,3-dibromo-2-methoxy-5-nitrobenzene was added. After the reaction was complete, the reaction mixture was diluted with dichloromethane, washed with water, dried with anhydrous sodium sulfate, filtered, and the solvent was evaporated under vacuum to obtain a yellow solid, 3,5-dibromo-4-methoxyaniline.

[0017] (4) Preparation of diethyl 5'-amino-2'-methoxy-[1,1'-:3'-,1'-triphenyl]-4,4'-dicarboxylic acid:

[0018] 3,5-Dibromo-4-methoxyaniline, (4-(ethoxycarbonyl)phenyl)boronic acid, K2CO3, and tetra(triphenylphosphine)palladium were added to a 500 mL Schlenk flask equipped with a stir bar. 1,4-Dioxane was transferred to the system. The reaction mixture was heated to 85 °C under N2 atmosphere for 72 hours. After cooling the reaction mixture to room temperature, the organic solvent was removed using a rotary evaporator. The resulting mixture was poured into water and extracted with dichloromethane. The combined organic layers were dried with anhydrous MgSO4 and the solvent was removed again using a rotary evaporator. The product fraction was purified by column chromatography on silica gel containing ethyl acetate / hexane at a ratio of 1:4 = v / v, yielding a pale yellow solid, diethyl 5'-amino-2'-methoxy-[1,1'-:3'-,1'-triphenyl]-4,4'-dicarboxylic acid.

[0019] (5) Preparation of 5'-amino-2'-methoxy-[1,1'-:3'-,1'-triphenyl]-4,4'-dicarboxylic acid:

[0020] Diethyl 5'-amino-2'-methoxy-[1,1'-:3'-,1'-triphenyl]-4,4'-dicarboxylic acid was dissolved in tetrahydrofuran, and an aqueous solution of NaOH was added. The mixture was stirred under reflux for 10 hours, and then the organic solvent was removed using a rotary evaporator. The aqueous phase was acidified to pH 2 using an aqueous solution of HCl. The precipitate was collected by filtration, washed with water, and dried under vacuum to give 5'-amino-2'-methoxy-[1,1'-:3'-,1'-triphenyl]-4,4'-dicarboxylic acid.

[0021] (6) Preparation of 5',5'-(1,3,6,8-tetraoxo-1,3,6,8-tetrahydrobenzo[lmn][3,8]phenanthroline-2,7-diyl)bis(2'-methoxy-[1,1'-:3',1'-triphenyl]-4,4'-dicarboxylic acid)(H4NDTB):

[0022] 5'-Amino-2'-methoxy-[1,1'-:3'-,1'-triphenyl]-4,4'-dicarboxylic acid and 1,4,5,8-naphthalenetetracarboxylic anhydride were added to a 250 mL Schlenk flask equipped with a stir bar. Degassed N,N-dimethylformamide (DMF) was transferred to the system. The reaction mixture was heated to 160 °C under N2 atmosphere for 12 hours. After cooling the reaction mixture to room temperature, hydrochloric acid was added to the product for acidification. The product was then poured into water, collected by filtration, washed with water, ethanol and acetone, and dried under vacuum to obtain a light yellow solid as ligand H4NDTB.

[0023] (7) Preparation of linear dicarboxylic acid TPDC-X:

[0024] Step 1:

[0025] p-Bromobenzene / 1,4-dibromo-2,3,5,6-tetramethylbenzene / 9,10-dibromoanthracene / 4,7-dibromobenzo[c][1,2,5]thiadiazole / 2,5-dibromopyridine / 1,4-dibromo-2,5-dimethoxybenzene, (4-(ethoxycarbonyl)phenyl)boronic acid / (4-(ethoxycarbonyl)-3,5-difluorophenyl)boronic acid, cesium carbonate, and tetra(triphenylphosphine)palladium were added to a 500 mL agitator. In a Schlenk flask, the degassed 1,4-dioxane was transferred to the system. The reaction mixture was heated to 85°C for 72 hours under a N2 atmosphere. After cooling the reaction mixture to room temperature, the organic solvent was removed using a rotary evaporator. The resulting mixture was poured into water and extracted with dichloromethane. The combined organic layers were dried over anhydrous MgSO4, and the solvent was removed again using a rotary evaporator. Ethyl acetate / hexane in a 1:4 v / v ratio was used as the eluent. The product fraction was purified by column chromatography on silica gel, and the fraction containing the product was evaporated to obtain compound 3,3'. 5,5'-Tetrafluoro-[1,1':4'-triphenyl]-4,4'-diethyl carboxylate / 2',3',5',6'-Tetramethyl-[1,1':4'-triphenyl]-4,4'-diethyl carboxylate / 4,4'-(anthracene-9,10-diyl)diethyl benzoate / 4,4'-(benzo[c][1,2,5]thiadiazole-4,7-diyl)diethyl benzoate / 4,4'-(pyridine-2,5-diyl)diethyl benzoate / 2',5'-dimethoxy-[1,1'-:4'-triphenyl]-4,4'-diethyl carboxylate;

[0026] Step 2:

[0027] Compounds 3,3',5,5'-tetrafluoro-[1,1':4'-triphenyl]-4,4'-diethyl dicarboxylate / 2',3',5',6'-tetramethyl-[1,1':4'-triphenyl]-4,4'-diethyl dicarboxylate / 4,4'-(anthracite-9,10-diyl)diethyl dibenzoate / 4,4'-(benzo[c][1,2,5]thiadiazole-4,7-diyl)diethyl dibenzoate / 4,4'-(pyridine-2,5-diyl)diethyl dibenzoate / 2',5'-dimethoxy-[1,1'-:4'-triphenyl]-4,4'-diethyl dicarboxylate were dissolved in tetrahydrofuran, and an aqueous solution of sodium hydroxide was added to the solution. The mixture was stirred under reflux for 10 hours, and then the organic solvent was removed using a rotary evaporator. The aqueous phase was acidified to pH 2 using hydrochloric acid solution. The precipitate was collected by filtration, washed with water, and dried under vacuum to give 3,3”,5,5”-tetrafluoro-[1,1'-:4'-triphenyl]-4,4'-dicarboxylic acid / 2',3',5',6'-tetramethyl-[1,1':4'-triphenyl]-4,4'-dicarboxylic acid / 4,4'-(anthracene-9 The ligands 1,10-diyl)dibenzoic acid / 4,4'-(benzo[c][1,2,5]thiadiazole-4,7-diyl)dibenzoic acid / 4,4'-(pyridine-2,5-diyl)dibenzoic acid / 2',5'-dimethoxy-[1,1'-:4'-triphenyl]-4,4'-dicarboxylic acid are named TPDC-X, where X represents different substituents modified on TPDC, including but not limited to 4Me, 4F, TDA, AN, Py, or 2OMe;

[0028] (8) Synthesis of NKM-908: Ligand H4NDTB, zirconium metal salt and benzoic acid were dissolved in an organic solvent, mixed thoroughly, and then subjected to a solvothermal reaction at 80-150℃. After the reaction was completed, the temperature was lowered to room temperature to obtain light yellow powder crystals. After washing and drying, metal-organic framework material was obtained.

[0029] (9) Synthesis of NKM-908-TPDC-X: The linear dicarboxylic acid ligand TPDC-X was dissolved in an organic solvent, where X represents different substituents modified by the side chain of the linear dicarboxylic acid ligand. Then NKM-908 was placed in the solvent, and after reaction at 80-150℃, it was washed and dried to obtain the metal-organic framework material.

[0030] (10) Synthesis of NKM-908 thin film: Ligand H4NDTB, zirconium metal salt and benzoic acid were dissolved in an organic solvent, ultrasonically mixed, inserted into an ITO conductive glass plate, and subjected to a solvothermal reaction at 80-150℃. After the reaction was completed, the temperature was lowered to room temperature to obtain a metal-organic framework thin film on ITO.

[0031] (11) Synthesis of NKM-908-TPDC-X film: The linear dicarboxylic acid ligand TPDC-X was dissolved in an organic solvent, and then the NKM-908 film was placed in it. After reacting at 80-150℃, it was washed and dried to obtain a metal-organic framework film.

[0032] The organic solvent is N,N-dimethylformamide or N,N-dimethylacetamide; the zirconium metal salt is selected from zirconium oxychloride octahydrate or anhydrous zirconium chloride.

[0033] The molar ratio of ligand H4NDTB to zirconium metal salt is 1:5 to 30.

[0034] When synthesizing zirconium-based metal-organic framework materials, the ratio of zirconium chloride to organic solvent and benzoic acid is 20 mg: 1-4 mL: 300-800 mg, preferably 20 mg: 3 mL: 500 mg;

[0035] When synthesizing zirconium-based metal-organic framework films, the ratio of zirconium oxychloride octahydrate to organic solvent and benzoic acid is 90 mg: 5-15 mL: 800-1600 mg, preferably 90 mg: 10 mL: 1000 mg.

[0036] The solvothermal reaction temperature for synthesizing the two mesoporous zirconium-based metal-organic framework powder materials is 100-130℃, and the time is 1 to 4 days; the solvothermal reaction temperature for synthesizing the thin film is 80-130℃, and the time is 30 minutes to 3 days.

[0037] The synthesis method of the two mesoporous zirconium-based metal-organic framework materials and their thin films is characterized by,

[0038] The ratio of ligand H4NDTB to organic solvent is 90 mg: 5-15 mL, preferably 80 mg: 10 mL.

[0039] This invention further protects the application of the two mesoporous zirconium-based metal-organic framework materials in electrochromism.

[0040] The beneficial effects of this invention are as follows:

[0041] (1) The ligands designed in this invention possess both redox activity and saturated uncoordinated open windows. The metal-organic framework material formed by the self-assembly of the designed ligands with zirconium metal has suitable pore sizes, which greatly facilitates the extraction and insertion of electrolyte cations during electrochromic processes. In addition, the presence of saturated uncoordinated open windows makes post-synthetic modification possible. By installing the linear dicarboxylic acid ligand TPDC-X into the original MOF, the electrochromic color change is altered, thus providing a simple and efficient electrochromic color control strategy.

[0042] (2) One example of the zirconium-based metal-organic framework material designed in this invention has a CSQ topology, which makes the material have good stability. After 10 electrochromic cycles, it can still maintain the original crystal phase, providing a reliable guarantee for the commercialization of this type of material in electrochromic processes.

[0043] This material largely addresses the challenges of color control in the current design of electrochromic MOF materials, which is both difficult, time-consuming, and labor-intensive. Furthermore, both zirconium-based metal-organic framework materials demonstrate significant potential for stable electrochromic cycling. This invention provides new insights for the design of subsequent metal-organic framework materials, greatly promoting their practical application in the field of electrochromism. Attached Figure Description

[0044] Figure 1 This is a schematic diagram of the synthesis of the organic ligands used in the materials of Example 1.

[0045] Figure 2 This is a schematic diagram illustrating the synthesis of the TPDC-X organic ligand used in this invention.

[0046] Figure 3 The NKM-908 material is respectively along c( Figure 3 a) and a( Figure 3 b) Crystal structure diagram of the axis.

[0047] Figure 4 The NKM-908-TPDC-X material is respectively along c( Figure 4 a) and a( Figure 4 b) Crystal structure diagram of the axis.

[0048] Figure 5 This is a topological diagram of the NKM-908 material.

[0049] Figure 6 This is a topological diagram of the NKM-908-TPDC-X material.

[0050] Figure 7 These are the X-ray powder diffraction (XRD) patterns of the NKM-908 and NKM-908-TPDC-X materials.

[0051] Figure 8 The image shows the X-ray powder diffraction (XRD) patterns of the NKM-908 and NKM-908-TPDC-X films.

[0052] Figure 9 The 77K nitrogen isotherm total adsorption curves of the NKM-908 and NKM-908-TPDC-X materials are shown below. Figure 3 a) and aperture distribution diagram

[0053] Figure 10 This is a pore size distribution diagram of the NKM-908 and NKM-908-TPDC-X materials.

[0054] Figure 11 This is a graph showing the electrochromic properties of the NKM-908 material. Figure 11 a is the cyclic voltammetry curve. Figure 11 b is the in-situ ultraviolet-visible spectrum. Figure 11 c represents the color obtained by CV scanning at a specific voltage.

[0055] Figure 12 This is a graph showing the electrochromic properties of the NKM-908-TPDC-X material. Figure 12 a represents the cyclic voltammetry curve of NKM-908-TPDC-2OMe. Figure 12 b is the in-situ UV-Vis spectrum of NKM-908-TPDC-2OMe. Figure 12 c represents the color of NKM-908-TPDC-2OMe under a specific voltage during CV scanning; Figure 12 d represents the cyclic voltammetry curve of NKM-908-TPDC-4F. Figure 12 e is the in-situ UV-Vis spectrum of NKM-908-TPDC-4F. Figure 12 f represents the color of the NKM-908-TPDC-4F under a specific voltage during CV scanning; Figure 12 g represents the cyclic voltammetry curve of NKM-908-TPDC-4Me. Figure 12 h is the in-situ UV-Vis spectrum of NKM-908-TPDC-4Me. Figure 12 i represents the color of NKM-908-TPDC-4Me under a specific voltage during CV scanning.

[0056] Figure 13 This is a graph showing the electrochromic properties of the NKM-908-TPDC-X material. Figure 13 a represents the cyclic voltammetry curve of NKM-908-TPDC-TDA. Figure 13 b is the in-situ UV-Vis spectrum of NKM-908-TPDC-TDA. Figure 13 c represents the color of the NKM-908-TPDC-TDA under a specific voltage during CV scanning; Figure 13 d represents the cyclic voltammetry curve of NKM-908-TPDC-AN. Figure 13 e is the in-situ UV-Vis spectrum of NKM-908-TPDC-AN. Figure 13 f represents the color of NKM-908-TPDC-AN under a specific voltage during CV scanning; Figure 13 g represents the cyclic voltammetry curve of NKM-908-TPDC-Py. Figure 13h is the in-situ UV-Vis spectrum of NKM-908-TPDC-Py. Figure 13 i represents the color of NKM-908-TPDC-Py under a specific voltage during CV scanning.

[0057] Figure 14 These are cyclic stability test diagrams of the NKM-908 and NKM-908-TPDC-X materials. Detailed Implementation

[0058] Example 1:

[0059] (1) Preparation of 2,6-dibromo-4-nitrophenol:

[0060] 4-Nitrophenol (2.78 g, 20 mmol), 4-methylbenzenesulfonic acid (7.61 g, 44.2 mmol), potassium bromide (7.14 g, 60 mmol), and NBS (7.12 g, 40 mmol) were dissolved in 50 mL of water, and the mixture was stirred at 40 °C for 2 hours. The reaction was cooled to room temperature, filtered to obtain a solid, washed with an aqueous solution of sodium bisulfite (3 × 100 mL), and dried to give the product (4.22 g, yield: 71%). 1 H NMR (400MHz, DMSO-d6) δ 8.38 (s, 2H) ppm, 11.04 (s, 1H).

[0061] (2) Preparation of 1,3-dibromo-2-methoxy-5-nitrobenzene:

[0062] Compound 2,6-dibromo-4-nitrophenol (5.94 g, 20 mmol), methyl iodine (3.8 mL, 60 mmol), and K₂CO₃ (4.14 g, 30 mmol) were dissolved in 100 mL of acetonitrile. The reaction mixture was heated under reflux for 18 hours and then cooled to room temperature. Acetonitrile was removed by rotary evaporation, and the resulting mixture was poured into water and extracted with dichloromethane (3 × 100 mL). The combined organic layers were dried over anhydrous MgSO₄ before further solvent removal using a rotary evaporator. The product was purified by column chromatography on silica gel using hexane as eluent, and the fraction containing the product was evaporated to give a white powdery compound as the product (4.31 g, yield: 70%). 1 H NMR (400MHz, CDCl3) δ3.98 (s, 3H), 8.42 (s, 2H) ppm.

[0063] (3) Preparation of 3,5-dibromo-4-methoxyaniline:

[0064] Iron (5 g, 89.2 mmol) and NH4Cl (3.6 g, 66 mmol) were added to a 100 mL round-bottom flask, followed by 10 mL of H2O. The mixture was stirred and refluxed in an oil bath at 100 °C for 30 min, and then 1,3-dibromo-2-methoxy-5-nitrobenzene (6.84 g, 22 mmol) was added. After the reaction was complete, the reaction mixture was diluted with 100 mL of dichloromethane, washed successively with water (50 mL), dried over anhydrous sodium sulfate, filtered, and the solvent was evaporated under vacuum. A yellow solid was given as 3,5-dibromo-4-methoxyaniline (4.55 g, yield: 74%). 1 H NMR (400MHz, CDCl3): δ3.78 (s, 3H), 5.33 (s, 2H), 6.80 (s, 1H) ppm.

[0065] (4) Preparation of diethyl 5'-amino-2'-methoxy-[1,1'-:3'-,1'-triphenyl]-4,4'-dicarboxylic acid:

[0066] 3,5-Dibromo-4-methoxyaniline (4.2 g, 15 mmol), (4-(ethoxycarbonyl)phenyl)boronic acid (8.73 g, 45 mmol), K₂CO₃ (8.28 g, 60 mmol), and tetrakis(triphenylphosphine)palladium (0.867 g, 0.75 mmol) were added to a 500 mL Schlenk flask equipped with a stir bar. 200 mL of 1,4-dioxane was transferred to the system. The reaction mixture was heated to 85 °C under a nitrogen atmosphere for 72 hours. After cooling the reaction mixture to room temperature, the organic solvent was removed using a rotary evaporator. The resulting mixture was poured into water and extracted with dichloromethane (3 × 50 mL). The combined organic layers were dried over anhydrous MgSO₄, and the solvent was removed again using a rotary evaporator. After purification by column chromatography on silica gel containing the product fraction using ethyl acetate / hexane (1:4 = v / v) as eluent, 4.27 g of 5'-amino-2'-methoxy-[1,1'-:3'-,1'-triphenyl]-4,4'-dicarboxylic acid diethyl ester (yield: 68%) was obtained as a pale yellow solid. 1 H NMR (400MHz, CDCl3): δ1.40 (t, 6H), 4.40 (q, 4H), 5.16 (s, 2H), 6.71 (s, 2H), 7.66 (d, 4H).

[0067] (5) Preparation of 5'-amino-2'-methoxy-[1,1'-:3'-,1'-triphenyl]-4,4'-dicarboxylic acid:

[0068] Diethyl 5'-amino-2'-methoxy-[1,1'-:3'-,1'-triphenyl]-4,4'-dicarboxylic acid (0.58 g, 1.4 mmol) was dissolved in 20 mL of tetrahydrofuran, and 30 mL of 10 M NaOH aqueous solution was added. The mixture was stirred under reflux for 10 hours, and then the organic solvent was removed using a rotary evaporator. The aqueous phase was acidified to pH 2 using 6 M HCl aqueous solution. The resulting precipitate was collected by filtration, washed with water (200 mL), and dried under vacuum to give 5'-amino-2'-methoxy-[1,1'-:3'-,1'-triphenyl]-4,4'-dicarboxylic acid (0.457 g, 90%). 1 H NMR (400MHz, CDCl3): δ2.95 (s, 3H), 5.17 (s, 2H), 6.63 (s, 2H), 7.67 (d, 4H), 7.99 (d, 4H), 12.91 (s, 2H) ppm.

[0069] (6) Preparation of 5',5'-(1,3,6,8-tetraoxo-1,3,6,8-tetrahydrobenzo[lmn][3,8]phenanthroline-2,7-diyl)bis(2'-methoxy-[1,1'-:3',1'-triphenyl]-4,4'-dicarboxylic acid)(H4NDTB):

[0070] 5'-Amino-2'-methoxy-[1,1'-:3'-,1'-triphenyl]-4,4'-dicarboxylic acid (3.64 g, 10 mmol) and 1,4,5,8-naphthalenetetracarboxylic anhydride (1.34 g, 5.0 mmol) were added to a 250 mL Schlenk flask equipped with a stir bar. 50 mL of degassed N,N-dimethylformamide (DMF) was transferred to the system. The reaction mixture was heated to 160 °C under a nitrogen atmosphere for 12 hours. After cooling the reaction mixture to room temperature, 5 mL of 1 mol / L hydrochloric acid was added to the product for acidification, followed by dissolution in 500 mL of water. The product was collected by filtration, washed with water, ethanol, and acetone, and dried under vacuum to give a pale yellow solid as ligand H4NDTB (3.95 g, yield = 82.3%). 1 H NMR (400MHz, DMSO-d6) δ3.19 (s, 6H), 7.64 (s, 4H), 7.75 (d, 8H), 8.05 (d), 8.68 (d, 8H), 13.02 (s, 4H) ppm. .

[0071] (7) Preparation of linear dicarboxylic acid TPDC-X:

[0072] Step 1:

[0073] p-Bromobenzene / 1,4-dibromo-2,3,5,6-tetramethylbenzene / 9,10-dibromoanthracene / 4,7-dibromobenzo[c][1,2,5]thiadiazole / 2,5-dibromopyridine / 1,4-dibromo-2,5-dimethoxybenzene (5 mmol), (4-(ethoxycarbonyl)phenyl)boronic acid / (4-(ethoxycarbonyl)-3,5-difluorophenyl)boronic acid (15 mmol), cesium carbonate (20 mmol), and tetra(triphenylphosphine)palladium (0.25 mmol) were added to a 500 mL Schlenk flask equipped with a magnetic stirrer. 200 mL of degassed 1,4-dioxane was transferred to the system. The reaction mixture was heated to 85 °C for 72 hours under a nitrogen atmosphere. After cooling the reaction mixture to room temperature, the organic solvent was removed using a rotary evaporator. The resulting mixture was poured into water and extracted with dichloromethane (3 × 50 mL). The combined organic layers were dried with anhydrous MgSO4, and then the solvent was removed again using a rotary evaporator. Using ethyl acetate / hexane (1:4 = v / v) as eluent, the product fraction was purified by column chromatography on silica gel and the fraction containing the product was evaporated to obtain compounds 3,3',5,5'-tetrafluoro-[1,1':4'-triphenyl]-4,4'-diethyl carboxylate / 2',3',5',6'-tetramethyl-[1,1':4'-triphenyl]-4,4'-diethyl carboxylate / 4,4'-(anthracite-9,10-diyl)diethyl benzoate / 4,4'-(benzo[c][1,2,5]thiadiazole-4,7-diyl)diethyl benzoate / 4,4'-(pyridine-2,5-diyl)diethyl benzoate / 2',5'-dimethoxy-[1,1'-:4'-triphenyl]-4,4'-diethyl carboxylate.

[0074] 3,3',5,5'-Tetrafluoro-[1,1':4'-triphenyl]-4,4'-dicarboxylic acid diethyl ester (yield: 72%). 1 HNMR (400MHz, CDCl3): δ7.93(s,4H),7.71(d,4H),4.34(q,4H),1.28(t,6H)ppm.

[0075] 2',3',5',6'-Tetramethyl-[1,1':4'-triphenyl]-4,4'-dicarboxylic acid diethyl ester (yield: 70%). 1 HNMR (400MHz, CDCl3): δ1.30(t,6H),1.92(s,12H),4.36(q,4H),7.30(d,4H),8.16(d,4H)ppm.

[0076] Diethyl 4,4'-(anthracene-9,10-diyl)dibenzoate (yield: 64%). 1H NMR (400MHz, CDCl3): δ1.50(t,6H),4.51(q,4H),7.39(d,4H),7.61(d,4H),7.64(d,4H),8.32(d,4H)ppm.

[0077] Diethyl 4,4'-(benzo[c][1,2,5]thiadiazole-4,7-diyl)dibenzoate (yield: 66%). 1 H NMR (400MHz, CDCl3): δ1.46(t,6H),4.45(q,4H),7.89(d,2H),8.10(d,4H),8.24(d,4H)ppm.

[0078] Diethyl 4,4'-(pyridin-2,5-diyl)dibenzoate (yield: 64%). 1 H NMR (400MHz, CDCl3): δ1.36(t,6H),4.36(q,4H),7.66(d,2H),7.83(d,1H),7.95(d,1H),8.05(d,2H),8.10(d,2H),8.12(d,2H),8.92(s,1H)ppm.

[0079] 2',5'-Dimethoxy-[1,1'-:4'-triphenyl]-4,4'-dicarboxylic acid diethyl ester (yield: 67%). 1 H NMR (400MHz, CDCl3): δ1.44(t,6H),3.83(s,6H),4.44(q,4H),7.02(s,2H),7.69(d,4H),8.13(d,4H)ppm.

[0080] Step 2:

[0081] Compound 3,3',5,5'-tetrafluoro-[1,1':4'-triphenyl]-4,4'-diethyl dicarboxylate / 2',3',5',6'-tetramethyl-[1,1':4'-triphenyl]-4,4'-diethyl dicarboxylate / 4,4'-(anthracite-9,10-diyl)diethyl dibenzoate / 4,4'-(benzo[c][1,2,5]thiadiazole-4,7-diyl)diethyl dibenzoate / 4,4'-(pyridine-2,5-diyl)diethyl dibenzoate / 2',5'-dimethoxy-[1,1'-:4'-triphenyl]-4,4'-diethyl dicarboxylate (1.4 mmol) was dissolved in 20 mL of tetrahydrofuran, and 30 mL of 10 M sodium hydroxide aqueous solution was added. The mixture was stirred under reflux for 10 hours, and then the organic solvent was removed using a rotary evaporator. The aqueous phase was acidified to pH 2 using an aqueous hydrochloric acid solution. The precipitate was collected by filtration, washed with water (200 mL), and dried under vacuum to obtain 3,3”, 5,5”-tetrafluoro-[1,1'-:4'-triphenyl]-4,4'-dicarboxylic acid / 2',3',5',6'-tetramethyl-[1,1':4'-triphenyl]-4,4'-dicarboxylic acid / 4,4'-(anthracite-9,10-diyl)dibenzoic acid / 4,4'-(benzo[c][1,2,5]thiadiazole-4,7-diyl)dibenzoic acid / 4,4'-(pyridine-2,5-diyl)dibenzoic acid / 2',5'-dimethoxy-[1,1'-:4'-triphenyl]-4,4'-dicarboxylic acid. The above ligands were named TPDC-X, where X represents different substituents modified on TPDC, such as 4Me, 4F, TDA, AN, Py, and 2OMe.

[0082] 3,3”,5,5”-Tetrafluoro-[1,1'-:4'-triphenyl]-4,4'-dicarboxylic acid (yield: 91%). 1 H NMR (400MHz, DMSO-d6): δ13.93(s,2H),7.96(s,4H),7.68(d,4H)ppm.

[0083] 2',3',5',6'-Tetramethyl-[1,1':4'-triphenyl]-4,4'-dicarboxylic acid (yield: 93%). 1 HNMR (400MHz, DMSO-d6): δ1.83(s,12H),7.26(d,4H),8.02(d,4H),13.01(s,2H)ppm.

[0084] 4,4'-(anthracite-9,10-diyl)dibenzoic acid (yield: 93%). 1HNMR (400MHz, DMSO-d6): δ7.48(d,4H),7.55(d,4H),7.63(d,4H),8.22(d,4H),13.14(s,2H)ppm.

[0085] 4,4'-(benzo[c][1,2,5]thiadiazole-4,7-diyl)dibenzoic acid (yield: 94%). 1 H NMR (400MHz, DMSO-d6): δ8.10(d,2H),8.15(d,4H),8.17(d,4H),13.04(s,2H)ppm.

[0086] 4,4'-(pyridin-2,5-diyl)dibenzoic acid (yield: 94%). 1 HNMR (400MHz, DMSO-d6): δ7.98(d,1H),8.04(d,2H),8.09(d,3H),8.22(d,2H),8.31(d,2H),9.12(s,1H),13.02(s,2H)ppm.

[0087] 2',5'-Dimethoxy-[1,1'-:4'-triphenyl]-4,4'-dicarboxylic acid (yield: 90%). 1 H NMR (400MHz, DMSO-d6): δ3.80(s,6H),7.13(s,2H),7.73(d,4H),8.02(d,4H),12.95(s,2H)ppm.

[0088] Please refer to the appendix for the above steps as well. Figure 1 and Figure 2 .

[0089] (8) Synthesis of NKM-908: Ligand H4NDTB (10mg), zirconium chloride (20mg) and benzoic acid (500mg) were dissolved in 3mL DMF and mixed thoroughly. Then, a solvothermal reaction was carried out at 120℃ for 3 days. After the reaction was completed, the mixture was cooled to room temperature to obtain light yellow powder crystals. After washing and drying, the metal-organic framework material NKM-908 was obtained.

[0090] (9) Synthesis of NKM-908-TPDC-X: 30 mg of linear dicarboxylic acid ligand TPDC-X (X represents different substituents modified by the side chain of the linear dicarboxylic acid ligand) was dissolved in DMF, and then 30 mg of NKM-908 was placed in it. After reacting at 100 °C for 1 day, the mixture was washed and dried to obtain the metal-organic framework material NKM-908-TPDC-X.

[0091] (10) Synthesis of NKM-908 thin film: 90 mg of ligand H4NDTB, 90 mg of zirconium oxychloride octahydrate and 1000 mg of benzoic acid were dissolved in 10 mL of DMF, ultrasonically mixed, inserted into an ITO conductive glass plate, and subjected to a solvothermal reaction at 120 °C for 3 days. After the reaction was completed, the temperature was lowered to room temperature to obtain NKM-908 metal-organic framework thin film on ITO.

[0092] (11) Synthesis of NKM-908-TPDC-X film: 30 mg of linear dicarboxylic acid ligand TPDC-X was dissolved in an organic solvent, and then NKM-908 film was placed in it. After reacting at 100°C for 1 day, the film was washed and dried to obtain NKM-908-TPDC-X metal-organic framework film.

[0093] The present invention uses the following instruments or methods to characterize and test the properties of materials.

[0094] (1) Single-crystal X-ray diffraction (XRD) tests were performed on NKM-908 material. Crystals were picked from the mother liquor, transferred to oil, and mounted on a loop ring for single-crystal XRD analysis. Diffraction data were obtained at 100 K using a Rigaku XtalAB ProMM007DW diffractometer. Data collection and reconstruction were performed using the CrystAlisPro program. The crystal structure of NKM-908 is shown below. Figure 3 As shown (drawn using Dianond software).

[0095] (2) Three-dimensional electron diffraction tests were performed on NKM-908-TPDC-4F material. Electron diffraction data of the NKM-908-TPDC-4F crystal were collected at room temperature using a Rigaku XtaLABSynergy ED, HyPix ED, and an electron source at 200 keV. The sample powder was dispersed in an ethanol solution and sonicated for 5 minutes, then dropped onto a copper grid. 3D electron diffraction data were collected after the surface of the copper grid had completely dried. Data processing was performed using CrysAlisPro, and all structures were solved using the intrinsic phase-determining method with ShelXT, and refined using ShelXL in the Olex2 graphical user interface. The crystal structure of NKM-908-TPDC-4F is shown below. Figure 4 As shown (drawn using Dianond software).

[0096] (3) The topology of NKM-908 was calculated using ToposPro software. The topology of NKM-908 is as follows: Figure 5 As shown (drawn using Dianond software).

[0097] (4) The topology of NKM-908-TPDC-4F was calculated using ToposPro software. The topology of NKM-908-TPDC-4F is as follows: Figure 6 As shown (drawn using Dianond software).

[0098] (5) The powder X-ray diffraction (PXRD) patterns of the NKM-908 and NKM-908-TPDC-4F materials prepared in this invention were collected on a Rigaku MiniFlex 600 diffractometer equipped with a copper target. The powder X-ray diffraction patterns of the NKM-908 and NKM-908-TPDC-4F materials are shown below. Figure 7 As shown (drawn using Origin software, simulated using Mercury software).

[0099] (6) The X-ray diffraction (PXRD) patterns of the NKM-908 and NKM-908-TPDC-4F thin films prepared in this invention were collected on a Rigaku MiniFlex 600 diffractometer equipped with a copper target. The X-ray diffraction patterns of the NKM-908 and NKM-908-TPDC-4F thin films are shown below. Figure 8 As shown (drawn using Origin software, simulated using Mercury software).

[0100] (7) N2 adsorption measurements were performed using a Micromeritics ASAP 2020 surface area and pore size analyzer. Low-pressure N2 adsorption isotherms of NKM-908 and NKM-908-TPDC-4F were measured at 77 K in a liquid nitrogen bath. The test results are as follows: Figure 9 and Figure 10 As shown, the BET specific surface areas of NKM-908, NKM-908-TPDC-4Me, NKM-908-TPDC-2OMe, NKM-908-TPDC-AN, NKM-908-TPDC-TDA, NKM-908-TPDC-Py, and NKM-908-TPDC-4F are 2924, 2196, 2291, 2125, 2569, 2566, and 2429 m², respectively. 2 .g -1 The apertures are approximately 2.7 nm and 1.2 nm, respectively, and they have triangular channels with a diameter of 1.2 nm and hexagonal channels with a diameter of 2.7 nm.

[0101] (8) The cyclic voltammetry curves of NKM-908 in this invention were tested on a CHI760E, and all measurements were performed using a standard three-electrode system. All measurements were performed with the electrolyte purged with nitrogen for 30 minutes in 0.1M [( nThe process was carried out in Bu)4N]PF6 / DMF. The working electrode was an NKM-908 thin-film ITO electrode, the reference electrode was Ag / AgCl, and a platinum mesh electrode was used as the counter electrode. In-situ UV-Vis spectroscopy testing: The UV-Vis spectrum of the thin-film electrode was tested using a 10mm long quartz cuvette, with a platinum wire as the counter electrode and Ag / AgCl as the reference electrode. 0.1M[( n Bu)4N]PF6 / DMF is the electrolyte. The color change of the film during CV scanning was captured using an iPhone 13.

[0102] Figure 11 a shows that the NKM-908 film exhibits two pairs of distinct redox peaks, located near -0.51V / -0.43V and -0.9V / -0.73V, respectively. Figure 11 c. It can be observed that the almost colorless NKM-908 film exhibits two reversible color changes (light yellow and green) under the potential changes during the CV scan. Figure 11 b represents in-situ UV-Vis absorption spectroscopy used to monitor real-time changes in the NKM-908 film. Without an external electric field, characteristic π-π* absorption bands of the NDI group at 364 nm and 382 nm were observed in the UV-Vis spectrum of the NKM-908 film. As the potential was applied to -0.6 V, these two peaks gradually decreased, while new absorption peaks appeared and intensified at 475 nm, 606 nm, 706 nm, and 786 nm, corresponding to NDI... ·- The formation of the species corresponds to the first color, pale yellow. When a potential is continuously applied to -1.4V, NDI... ·- Species continue to be reduced to NDI 2- At this point, the absorption peak at 475 nm decreases, while new absorption peaks appear at 398 nm, 422 nm, 575 nm, and 625 nm. These absorption peaks increase as the potential rises to -1.4 V. This corresponds to the second color, green.

[0103] (9) The cyclic voltammetry curves of NKM-908-TPDC-X in this invention were tested on a CHI760E, and all measurements were performed using a standard three-electrode system. All measurements were performed with the electrolyte purged with nitrogen for 30 minutes in 0.1M [( n The process was carried out in Bu)4N]PF6 / DMF. The working electrode was an NKM-908-TPDC-X thin-film ITO electrode, the reference electrode was Ag / AgCl, and a platinum mesh electrode was used as the counter electrode. In-situ UV-Vis spectroscopy testing: The UV-Vis spectrum of the thin-film electrode was tested using a 10mm long quartz cuvette, with a platinum wire as the counter electrode and Ag / AgCl as the reference electrode. 0.1M[( nBu)4N]PF6 / DMF is the electrolyte. The color change of the film during CV scanning was captured using an iPhone 13.

[0104] First, three non-redox linear dicarboxylic acid ligands, TPDC-2OMe, TPDC-4Me, and TPDC-4F, were successfully mounted onto NKM-908 films for investigation. The CV curves of the NKM-908-TPDC-2OMe, NKM-908-TPDC-4Me, and NKM-908-TPDC-4F films showed no difference from those of NKM-908. Figure 12 a, d, g (inset shows the installed TPDC-X ligand), and two sets of redox peaks were detected at -0.51V / 0.43V and -0.9V / 0.73V, respectively. Simultaneously, their color changed from pale yellow to deep yellow, and then to green. Figure 12 (c, f, i). However, throughout the entire electrochromic process, the color of the film after the connector was mounted was darker than that of NKM-908. In-situ UV-Vis spectroscopy revealed the electrochromic groups NDI, NDI... ·- and NDI 2- Characteristic absorption peaks ( Figure 12 b, e, h).

[0105] This invention further designs the in-situ mounting of three redox-active TPDC ligands (TPDC-TDA, TPDC-AN, and TPDC-Py) into an NKM-908 film. Unlike the CV curve of the NKM-908 film, the NKM-908-TPDC-TDA film exhibits two sets of redox peaks with different positions, located at -0.9V / -0.73V and -1.42V / -1.3V, respectively. Figure 13 a. The illustration shows the installed TPDC-TDA ligand. The first set of peaks corresponds to the oxidation and reduction processes of the NDI unit, while the second set of peaks corresponds to the oxidation and redox processes of the TDA component. During the CV process, the NKM-908-TPDC-TDA film exhibits a reversible color transition from light yellow to dark yellow, then to purple, and finally to green. Figure 13 c) Simultaneously monitored ultraviolet-visible spectra, such as Figure 13As shown in b, when the potential is applied from 0V to -1.1V, a gradual increase in the absorption band at 384nm can be observed. This observation is consistent with the characteristic π-π* absorption band of the NDI group, which corresponds to a gradual color change from light yellow to deep yellow. Interestingly, when the potential is increased from -1.6V to -2V, a new absorption peak at 520nm appears at -1.6V and gradually weakens with increasing potential. This new peak is in the purple state during the color change, which is attributed to the single-electron reduction process of the TDA portion. When a potential is further applied from -2V to -2.3V, the absorption peak at 520nm gradually weakens and disappears. Simultaneously, new absorption peaks are generated at 398nm, 422nm, 575nm, and 625nm, which are attributed to NDI. 2- Therefore, the film turns green.

[0106] Two sets of redox peaks, -0.91V / -0.77V and -1.80V / -1.97V, can be clearly observed in the CV curve of the NKM-908-TPDC-AN film. These correspond to the redox processes of NDI and anthracene, respectively. Figure 13 d). During the CV scanning process, the film color changed from almost colorless to blue, and then to light green. Figure 13 f). Exploring color changes during electrochromic processes using in-situ ultraviolet-visible absorption spectroscopy ( Figure 13 e). Absorption peaks were detected at 356 nm, 374 nm, and 395 nm without an applied potential, due to the characteristic absorption peaks of anthracene in TPDC-AN and the characteristic π-π* absorption band of NDI. As the potential increased to -1.1 V, the absorption at these three positions gradually increased, attributed to the characteristic absorption peaks during the redox reaction of anthracene. When the potential was further changed to -2.2 V, the film turned light green, and new absorption peaks appeared at 625 nm, 575 nm, and 422 nm, indicating the presence of NDI. 2- The formation of.

[0107] Installing the TPDC Py connector also enables electrochromic color adjustment. Figure 13 The CV curve of the NKM-908-TPDC-Py film is shown in the image, clearly showing two sets of redox peaks (-0.9V / -0.73V and -2.16V / -2.04V). The first set of peaks corresponds to the redox peaks of the NDI unit, while the second set belongs to the redox peaks of TPDC Py. Simultaneously, during the CV scan, the film color changes from almost colorless to deep yellow and then to deep pink at 0V, -1.1V, and -2.2V. Figure 13 i). Figure 13h represents the in-situ UV-Vis absorption spectrum of the tested NKM-908-TPDC-Py thin film. No absorption peak was detected at 0 V. As the potential gradually increased to -1.1 V, new absorption peaks appeared at 355 nm and 378 nm, with the intensity gradually increasing along this process, corresponding to the deep yellow state in electrochromism. During the potential change from -1.1 V to -2.2 V, new absorption peaks were generated at 448 nm, 488 nm, and 810 nm, corresponding to the deep pink state in electrochromism.

[0108] (10) The cycling stability curves of NKM-908 and NKM-908-TPDC-X in this invention were tested on a CHI760E and a Kenfan Electronics Technology KU-T1810. All measurements were performed using a standard three-electrode system. A 10mm long quartz cuvette was used as the container, the thin film was used directly as the working electrode, a platinum wire was used as the counter electrode, Ag / AgCl was used as the reference electrode, and 0.1M [( n Bu)4N]PF6 / DMF is the electrolyte.

[0109] The cycle stability of NKM-908, NKM-908-TPDC-2OMe, NKM-908-TPDC-4F, and NKM-908-TPDC-4Me was determined by alternating cycles at 0V and -1.4V. The values ​​for NKM-908-TPDC-TDA, NKM-908-TPDC-AN, and NKM-908-TPDC-Py were also assessed. Figure 14 The results showed that neither NKM-908 nor NKM-908-TPDC-X exhibited significant degradation after 10 cycles.

[0110] It should be further noted that the above embodiments are only used for understanding the technical solution of the present invention and are not intended to limit the scope of protection of the present invention. Any obvious adjustments and modifications made to the technical concept of the present invention should also be within the scope of protection of the present invention.

Claims

1. Two mesoporous zirconium-based metal-organic framework materials, characterized in that, The metal is Zr, and 5',5''-(1,3,6,8-tetraoxo-1,3,6,8-tetrahydrobenzo[lmn][3,8]phenanthroline-2,7-diyl)bis(2'-methoxy-[1,1'-:3',1'-triphenyl]-4,4'-dicarboxylic acid) (H4NDTB) is used as a ligand. All the carboxylic acid groups in the ligand participate in coordination and coordinate with zirconium to form a metal-organic framework material. The framework structure is a three-dimensional network structure containing one-dimensional mesoporous channels. Two mesoporous zirconium-based metal-organic framework materials exhibit hexagonal lattice characteristics with space group P6 / mmm. The cell parameters of the materials are a=b=40.285, c=23.6990, α=β=90°, γ=120° and a=b=40.54, c=23.45, α=β=90°, γ=120°, respectively. The pore types of the two materials are 1.2 nm triangular micropores and 2.7 nm one-dimensional hexagonal mesopores.

2. The preparation method of the two mesoporous zirconium-based metal-organic framework materials according to claim 1, characterized in that, Includes the following steps: (1) Preparation of 2,6-dibromo-4-nitrophenol: 4-Nitrophenol, 4-methylbenzenesulfonic acid, potassium bromide and NBS were dissolved in water. The mixture was stirred at 40 °C for 2 hours. The reaction was cooled to room temperature, filtered to obtain a solid, washed with sodium metabisulfite aqueous solution, and dried to obtain the product. (2) Preparation of 1,3-dibromo-2-methoxy-5-nitrobenzene: Compound 2,6-dibromo-4-nitrophenol, methyl iodine, and K2CO3 were dissolved in acetonitrile. The reaction mixture was heated under reflux for 18 hours and then cooled to room temperature. Acetonitrile was removed by rotary evaporation. The resulting mixture was poured into water and extracted with dichloromethane. Before removing the solvent again using a rotary evaporator, the combined organic layers were dried with anhydrous MgSO4. The mixture was purified by silica gel column chromatography using hexane as eluent to obtain a white powder product. (3) Preparation of 3,5-dibromo-4-methoxyaniline: Iron and NH4Cl were added to a 100 mL round-bottom flask, followed by H2O. The mixture was stirred and refluxed in an oil bath at 100°C for 30 minutes. Then, 1,3-dibromo-2-methoxy-5-nitrobenzene was added. After the reaction was complete, the reaction mixture was diluted with dichloromethane, washed with water, dried with anhydrous sodium sulfate, and filtered. The solvent was removed by rotary evaporation to obtain a yellow solid, 3,5-dibromo-4-methoxyaniline. (4) Preparation of diethyl 5'-amino-2'-methoxy-[1,1'-:3'-,1'-triphenyl]-4,4'-dicarboxylic acid: 3,5-Dibromo-4-methoxyaniline, (4-(ethoxycarbonyl)phenyl)boronic acid, K2CO3, and tetra(triphenylphosphine)palladium were added to a 500 mL Schlenk flask equipped with a stir bar. 1,4-Dioxane was transferred to the system. The reaction mixture was heated to 85 °C under N2 atmosphere for 72 hours. After cooling the reaction mixture to room temperature, the organic solvent was removed using a rotary evaporator. The resulting mixture was poured into water and extracted with dichloromethane. The combined organic layers were dried with anhydrous MgSO4 and the solvent was removed again using a rotary evaporator. The mixture was purified by silica gel column chromatography using ethyl acetate / hexane at a volume ratio of 1:4 as the eluent to obtain a pale yellow solid, 5'-amino-2'-methoxy-[1,1'-:3'-,1'-triphenyl]-4,4'-dicarboxylic acid diethyl ester. (5) Preparation of 5'-amino-2'-methoxy-[1,1'-:3'-,1'-triphenyl]-4,4'-dicarboxylic acid: Diethyl 5'-amino-2'-methoxy-[1,1'-:3'-,1'-triphenyl]-4,4'-dicarboxylic acid was dissolved in tetrahydrofuran, and an aqueous solution of NaOH was added. The mixture was stirred under reflux for 10 hours, and then the organic solvent was removed using a rotary evaporator. The aqueous phase was acidified to pH 2 using an aqueous solution of HCl. The precipitate was collected by filtration, washed with water, and dried under vacuum to give 5'-amino-2'-methoxy-[1,1'-:3'-,1'-triphenyl]-4,4'-dicarboxylic acid. (6) Preparation of 5',5'-(1,3,6,8-tetraoxo-1,3,6,8-tetrahydrobenzo[lmn][3,8]phenanthroline-2,7-diyl)bis(2'-methoxy-[1,1'-:3',1'-triphenyl]-4,4'-dicarboxylic acid) (H4NDTB): 5'-Amino-2'-methoxy-[1,1'-:3'-,1'-triphenyl]-4,4'-dicarboxylic acid and 1,4,5,8-naphthalenetetracarboxylic anhydride were added to a 250 mL Schlenk flask equipped with a stir bar. Degassed N,N-dimethylformamide was transferred to the system. The reaction mixture was heated to 160 °C under N2 atmosphere for 12 hours. After cooling the reaction mixture to room temperature, hydrochloric acid was added to the product for acidification. The product was then poured into water, collected by filtration, washed with water, ethanol and acetone, and dried under vacuum to obtain a light yellow solid as ligand H4NDTB. (7) Preparation of linear dicarboxylic acid TPDC-X: Step 1: p-Bromobenzene / 1,4-dibromo-2,3,5,6-tetramethylbenzene / 9,10-dibromoanthracene / 4,7-dibromobenzo[c][1,2,5]thiadiazole / 2,5-dibromopyridine / 1,4-dibromo-2,5-dimethoxybenzene, (4-(ethoxycarbonyl)phenyl)boronic acid / (4-(ethoxycarbonyl)-3,5-difluorophenyl)boronic acid, cesium carbonate, and tetra(triphenylphosphine)palladium were added to a 500 mL Schlenk flask equipped with a magnetic stirrer. The degassed 1,4-dioxane was transferred to the system, and the reaction mixture was heated to 85 °C under a nitrogen atmosphere. After 72 hours, the reaction mixture was cooled to room temperature, and the organic solvent was removed using a rotary evaporator. The resulting mixture was poured into water and extracted with dichloromethane. The combined organic layers were dried over anhydrous MgSO4, and the solvent was removed again using a rotary evaporator. The mixture was purified by silica gel column chromatography using ethyl acetate / hexane at a volume ratio of 1:4 to obtain compounds 3,3',5,5'-tetrafluoro-[1,1':4'-triphenyl]-4,4'-dicarboxylic acid diethyl ester / 2',3',5',6'-tetramethyl-[1,1':4'-triphenyl]-4,4'-dicarboxylic acid diethyl ester / 4,4'-(anthracite-9,10-diyl)dibenzoate diethyl ester / 4,4'-(benzo[c][1,2,5]thiadiazole-4,7-diyl)dibenzoate diethyl ester / 4,4'-(pyridine-2,5-diyl)dibenzoate diethyl ester / 2',5'-dimethoxy-[1,1'-:4'-triphenyl]-4,4'-dicarboxylic acid diethyl ester; Step 2: The compounds 3,3',5,5'-tetrafluoro-[1,1':4'-triphenyl]-4,4'-diethyl dicarboxylate / 2',3',5',6'-tetramethyl-[1,1':4'-triphenyl]-4,4'-diethyl dicarboxylate / 4,4'-(anthracite-9,10-diyl)diethyl dibenzoate / 4,4'-(benzo[c][1,2,5]thiadiazole-4,7-diyl)diethyl dibenzoate / 4,4'-(pyridine-2,5-diyl)diethyl dibenzoate / 2',5'-Dimethoxy-[1,1'-:4'-triphenyl]-4,4'-dicarboxylic acid diethyl ester was dissolved in tetrahydrofuran, and an aqueous sodium hydroxide solution was added. The mixture was stirred under reflux for 10 hours, and the organic solvent was removed using a rotary evaporator. The aqueous phase was acidified to pH 2 using an aqueous hydrochloric acid solution. The precipitate was collected by filtration, washed with water, and dried under vacuum to give 3,3'',5,5''-tetrafluoro-[1,1'-:4'-triphenyl]-4,4'-dicarboxylic acid / 2',3',5',6'-tetramethyl-[1,1'-:4'-triphenyl]-4,4'-dicarboxylic acid. The ligands ':4'-triphenyl]-4,4'-dicarboxylic acid / 4,4'-(anthracite-9,10-diyl)dibenzoic acid / 4,4'-(benzo[c][1,2,5]thiadiazole-4,7-diyl)dibenzoic acid / 4,4'-(pyridine-2,5-diyl)dibenzoic acid / 2',5'-dimethoxy-[1,1'-:4'-triphenyl]-4,4'-dicarboxylic acid are named TPDC-X, where X represents a different substituent modified on TPDC, including 4Me, 4F, TDA, AN, Py, or 2OMe; (8) Synthesis of NKM-908: The ligand H4NDTB, zirconium metal salt and benzoic acid were dissolved in an organic solvent and mixed thoroughly. Then, a solvothermal reaction was carried out at 80-150 °C. After the reaction was completed, the temperature was lowered to room temperature to obtain light yellow powder crystals. After washing and drying, the metal-organic framework material was obtained. (9) Synthesis of NKM-908-TPDC-X: The linear dicarboxylic acid ligand TPDC-X was dissolved in an organic solvent, where X represents different substituents modifying the side chain of the linear dicarboxylic acid ligand. Then, NKM-908 was added to the solvent. After reaction at 80-150 ℃, the material is washed and dried to obtain a metal-organic framework material. (10) Synthesis of NKM-908 thin films: The ligand H4NDTB, zirconium metal salt and benzoic acid were dissolved in an organic solvent, ultrasonically mixed, inserted into an ITO conductive glass sheet, and subjected to a solvothermal reaction at 80-150 °C. After the reaction was completed, the temperature was lowered to room temperature to obtain a metal-organic framework film on ITO. (11) Synthesis of NKM-908-TPDC-X film: The linear dicarboxylic acid ligand TPDC-X was dissolved in an organic solvent, and then the NKM-908 film was placed in it. After reacting at 80-150 °C, the film was washed and dried to obtain a metal-organic framework film.

3. The preparation method of the two mesoporous zirconium-based metal-organic framework materials according to claim 2, characterized in that, The organic solvent is N,N-dimethylformamide or N,N-dimethylacetamide; the zirconium metal salt is selected from zirconium oxychloride octahydrate or anhydrous zirconium chloride.

4. The preparation method of the two mesoporous zirconium-based metal-organic framework materials according to claim 2, characterized in that, The molar ratio of ligand H4NDTB to zirconium metal salt is 1:5 to 30.

5. The preparation method of the two mesoporous zirconium-based metal-organic framework materials according to claim 3, characterized in that, When synthesizing zirconium-based metal-organic framework materials, the ratio of zirconium metal salt to organic solvent and benzoic acid is 20 mg: 1-4 mL: 300-800 mg; When preparing zirconium-based metal-organic framework films, the ratio of zirconium metal salt to organic solvent and benzoic acid is 90 mg: 5-15 mL: 800-1600 mg.

6. The method for synthesizing the two mesoporous zirconium-based metal-organic framework materials according to claim 2, characterized in that, The solvothermal reaction temperature for synthesizing powder materials is 100-130 ℃, and the time is 1 to 4 days; the solvothermal reaction temperature for synthesizing thin films is 80-130 ℃, and the time is 30 minutes to 3 days.

7. The method for synthesizing the two mesoporous zirconium-based metal-organic framework materials according to claim 2, characterized in that, The ratio of ligand H4NDTB to organic solvent is 90 mg: 5–15 mL.

8. The application of the two mesoporous zirconium-based metal-organic framework materials as described in claim 1 in electrochromism.

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