A porous crystalline material, a method for preparing the same and use as a thermoluminescent material

Abstract

The application provides a kind of porous crystalline material and its preparation method and application as variable temperature luminescent material, belong to metal organic framework material technical field.The molecular formula is: C 25 H 21 NO8PLn, wherein Ln is europium ion or terbium ion.The material contains dynamic molecular rotor module ligand H3TPO, and the energy level of the lowest excited singlet state (S1) and triplet state (T1) can be elastically adjusted with temperature change, and this characteristic makes isomorphic materials Eu-PO and Tb-PO exhibit rare and completely opposite thermoluminescence behavior.The application not only provides a new idea for regulating the energy level of dynamic antenna to construct artificial intelligent luminescent material, but also opens up a new direction for developing high-performance X-ray scintillators based on Ln-MOFs.

Description

Technical Field

[0001] This invention relates to the field of metal-organic framework materials technology, and in particular to a porous crystalline material, its preparation method, and its application as a temperature-variable luminescent material. Background Technology

[0002] Metal-organic frameworks (MOFs) are periodic porous crystalline materials formed by the self-assembly of inorganic metal nodes and organic ligands through coordination bonds. They have become a research hotspot in chemistry and materials science due to their ultra-high specific surface area, tunable structure, and ease of functionalization. Lanthanide complex luminescent materials have attracted considerable attention due to their unique optical properties, such as pure-color emission, long luminescence lifetime, large Stokes shift, narrow full width at half maximum (FWHM), and excellent light absorption.

[0003] Currently, the core strategy for constructing such luminescent materials still mainly relies on "static" organic fluorophores with highly conjugated and rigid structures as antenna units. The energy levels of these fluorophores are very precise and difficult to dynamically change, thus preventing flexible control of excited-state energy levels. Against this backdrop, the emergence of aggregation-induced emission (AIE) luminescent materials (AIEgens) has brought new opportunities to this field. Compared to traditional rigid fluorophores, the optical properties and energy levels of AIEgens are closely related to their molecular conformation and rotor motion. Even small perturbations of the external environment to AIE molecules can rapidly change the degree of motion or twisting state of their molecular rotors, leading to dynamic changes in their energy levels. One innovative strategy utilizes lanthanide ions or lanthanide clusters with excellent photophysical properties and characteristic emission spectra as secondary building blocks (SBUs), and alternately connects them with dynamic molecular rotors as organic linkers through self-assembly, thereby forming dynamic lanthanide organic frameworks (Ln-MOFs). The degree of twisting and conformational changes of the molecular rotor in the AIE ligand directly affect the changes in its energy levels, thus achieving an adaptive antenna effect for lanthanide ions at different energy levels. This mechanism can not only effectively regulate the characteristic luminescence of lanthanide ions, but also lay the theoretical foundation for the development of intelligent multifunctional luminescent materials. Summary of the Invention

[0004] The purpose of this invention is to provide a porous crystalline material, its preparation method, and its application as a temperature-variable luminescent material, in order to solve the technical problem of controlling the change in luminescence intensity of the material at different temperatures.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides a porous crystalline material, the molecular formula of which is: C 25 H 21 NO8PLn, where Ln is a europium ion or a terbium ion.

[0006] Furthermore, when Ln is europium ion, the material is represented as Eu-PO with cell parameters a = 10.8175 (3) Å, b = 11.7886 (3) Å, c = 14.3357 (3) Å, α = 75.317 (2) (deg), β = 74.143 (2) (deg), γ = 68.352 (2) (deg).

[0007] Furthermore, the Eu-PO is a porous three-dimensional structure formed by H3TPO linker chelating secondary building units SBUs; SBUs consist of eight twisted TPOs 3- The connector connects two LnO8 polyhedra, and each SBU contains Ln 3+ Ions are respectively connected to six TPO 3- TPO with a linker and a terminal-coordinated solvent molecule twisted in the Eu-PO structure. 3- The dihedral angles between the three benzene rings of the linker are 54.61° / 82.05° / 76.46°, respectively; the twisted and dynamic TPO within the Eu-PO structure 3- The linker has only one coordination mode. μ 6- η 2 : η 1 : η 1 : η 1 : η 1 : η 1 It exhibits a 4,8-c topological connectivity and {4 12 0.6 12 0.8 4}{4 6 Connect the topological points of}2.

[0008] Furthermore, when Ln is a terbium ion, the material is represented as Tb-PO with cell parameters a = 10.7967 (1) Å, b = 11.7607 (2) Å, c = 14.2246 (2) Å, α = 75.745 (1) (deg), β = 74.563 (1) (deg), and γ = 68.170 (1) (deg).

[0009] Furthermore, the Tb-PO is a porous three-dimensional structure formed by H3TPO linker chelating secondary building units SBUs; SBUs consist of eight twisted TPOs 3-The connector connects two LnO8 polyhedra, and each SBU contains Ln 3+ Ions are respectively connected to six TPO 3- A linker and a terminal-coordinated DMA solvent molecule, TPO twisted in a Tb-PO structure. 3- The dihedral angles between the three benzene rings of the linker are 54.34°, 82.56°, and 77.88°, respectively.

[0010] This invention also provides a method for preparing porous crystalline materials, comprising the following steps: The porous crystalline material is obtained by reacting 4,4',4''-phosphoryltribenzoic acid, europium nitrate, or terbium nitrate in a solvent and then cooling the mixture.

[0011] Furthermore, the molar ratio of the 4,4',4''-phosphoryltribenzoic acid to europium nitrate or terbium nitrate is 1:0.8~1.2; The solvent is water and N , N -A mixed solvent of dimethylacetamide, water and N , N The volume ratio of dimethylacetamide is 1:1~3.

[0012] Furthermore, the ratio of 4,4',4''-phosphoryltribenzoic acid to solvent is 0.05 mmol: 2~5 mL.

[0013] Furthermore, the reaction temperature is 90~110℃, and the reaction time is ≥48h.

[0014] This invention also provides an application of porous crystalline materials as temperature-variable luminescent materials.

[0015] The beneficial effects of this invention are: The present invention provides a simple and efficient synthetic route for crystalline porous materials constructed from 4,4',4''-phosphoryltribenzoic acid, with ideal yields and products exhibiting bright red (Eu-PO) and green (Tb-PO) luminescence. Within the temperature range of 80 K to 460 K, the luminescence intensity of Eu-PO shows a temperature-dependent thermally enhanced luminescence behavior, while the luminescence intensity of Tb-PO shows a significant thermal quenching behavior with increasing temperature. Attached Figure Description

[0016] Figure 1 This is a structural diagram of the porous material Eu-PO; Figure 2 This is a structural diagram of the porous material Tb-PO; Figure 3The diagram shows the ligand coordination mode and topological structure of porous materials Eu-PO and Tb-PO. Figure 4 Powder diffraction (PXRD) patterns of porous materials Eu-PO and Tb-PO; Figure 5 SEM, TEM, and EDS images of porous materials Eu-PO and Tb-PO; Figure 6 Thermogravimetric curve of the porous material Eu-PO; Figure 7 The temperature-varying emission spectrum of the porous material Eu-PO in the temperature range of 80-460 K is shown. Figure 8 The temperature-varying emission spectrum of the porous material Tb-PO in the temperature range of 80-460 K is shown. Figure 9 The single-crystal structures of the porous material Eu-PO under different temperature conditions (100 K, 150 K, 200 K, 300 K, 373 K) are shown. Figure 10 The temperature-dependent phosphorescence spectrum of porous material Gd-PO in the range of 80-480 K; Figure 11 This is a schematic diagram illustrating the distinctly different temperature-dependent luminescence behaviors of porous materials Eu-PO and Tb-PO due to the dynamic changes in the T1 state energy level. Figure 12 The diagram shows the excellent X-ray scintillator performance of the porous material Tb-PO. Detailed Implementation

[0017] This invention provides a porous crystalline material, the molecular formula of which is: C 25 H 21 NO8PLn, where Ln is a europium ion or a terbium ion.

[0018] In this invention, when Ln is europium ion, the material is represented as Eu-PO with cell parameters a = 10.8175 (3) Å, b = 11.7886 (3) Å, c = 14.3357 (3) Å, α = 75.317 (2) (deg), β = 74.143 (2)(deg), γ = 68.352 (2) (deg).

[0019] In this invention, the Eu-PO is a porous three-dimensional structure formed by H3TPO linker chelating secondary building units SBUs; SBUs consist of eight twisted TPOs 3- The connector connects two LnO8 polyhedra, and each SBU contains Ln3+ Ions are respectively connected to six TPO 3- TPO with a linker and a terminal-coordinated solvent molecule twisted in the Eu-PO structure. 3- The dihedral angles between the three benzene rings of the linker are 54.61° / 82.05° / 76.46°, respectively; the twisted and dynamic TPO within the Eu-PO structure 3- The linker has only one coordination mode. μ 6- η 2 : η 1 : η 1 : η 1 : η 1 : η 1 It exhibits a 4,8-c topological connectivity and {4 12 0.6 12 0.8 4}{4 6 Connect the topological points of}2.

[0020] In this invention, when Ln is a terbium ion, the material is represented as Tb-PO with cell parameters a = 10.7967 (1) Å, b = 11.7607 (2) Å, c = 14.2246 (2) Å, α = 75.745 (1) (deg), β = 74.563 (1) (deg), and γ = 68.170 (1) (deg).

[0021] In this invention, the Tb-PO is a porous three-dimensional structure formed by H3TPO linker chelating secondary building units SBUs; SBUs consist of eight twisted TPOs 3- The connector connects two LnO8 polyhedra, and each SBU contains Ln 3+ Ions are respectively connected to six TPO 3- A linker and a terminal-coordinated DMA solvent molecule, TPO twisted in a Tb-PO structure. 3- The dihedral angles between the three benzene rings of the linker are 54.34°, 82.56°, and 77.88°, respectively.

[0022] This invention also provides a method for preparing porous crystalline materials, comprising the following steps: The porous crystalline material is obtained by reacting 4,4',4''-phosphoryltribenzoic acid, europium nitrate, or terbium nitrate in a solvent and then cooling the mixture.

[0023] In this invention, the molar ratio of 4,4',4''-phosphoryltribenzoic acid to europium nitrate or terbium nitrate is 1:0.8~1.2, preferably 1:0.9~1.1, and more preferably 1:1; The solvent is water and N , N -A mixed solvent of dimethylacetamide, water and N , N The volume ratio of dimethylacetamide is 1:1 to 3, preferably 1:1.2 to 2.8, and more preferably 1:2.

[0024] In this invention, the ratio of 4,4',4''-phosphoryltribenzoic acid to solvent is 0.05 mmol: 2~5 mL, preferably 0.05 mmol: 3 mL.

[0025] In this invention, the reaction temperature is 90~110℃, preferably 95~105℃, and more preferably 100℃; the reaction time is ≥48h, preferably ≥60h, and more preferably 72h.

[0026] This invention also provides an application of porous crystalline materials as temperature-variable luminescent materials.

[0027] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0028] Example 1

[0029] Synthesis and structural analysis of crystalline porous material Eu-PO

[0030] 0.05 mmol of 4,4',4''-phosphoryltribenzoic acid (H3TPO) and 0.05 mmol of europium nitrate hexahydrate were added to a 25 mL polytetrafluoroethylene reactor, followed by the addition of 1 mL of water and 2 mL of [unspecified ingredient]. N , N Dimethylacetamide (DMA) was stirred with a magnetic stirrer for 30 minutes and then reacted in an oven at 100°C for 72 hours. After slow cooling, colorless and transparent bulk crystals were obtained, with a yield of approximately 87.67% (based on the amount of europium nitrate hexahydrate). The unit cell parameters are... a =10.8175 (3) Å, b = 11.7886 (3) Å, c = 14.3357 (3) Å, α = 75.317 (2) (deg), β = 74.143 (2) (deg), γ =68.352 (2) (deg).

[0031] Figure 1 This is a structural diagram of the crystalline porous material Eu-PO, which has a porous three-dimensional structure formed by H3TPO linker chelate secondary building units (SBUs). The SBUs consist of eight twisted TPO... 3- Connectors link two LnO8 polyhedra. Each SBU contains Ln... 3+ Ions are respectively connected to six TPO 3- A linker and a terminal group coordinated DMA solvent molecule. TPO twisted within an Eu-PO structure. 3- The dihedral angles between the three benzene rings of the linker are 54.61°, 82.05°, and 76.46°, respectively.

[0032] Example 2

[0033] Synthesis and structural analysis of crystalline porous material Tb-PO

[0034] Add 0.05 mmol of 4,4',4''-phosphoryltribenzoic acid (H3TPO) and 0.05 mmol of terbium nitrate hexahydrate to a 25 mL polytetrafluoroethylene reactor, then add 1 mL of water and 2 mL of [other chemicals]. N , N After reacting with dimethylacetamide (DMA), the mixture was stirred magnetically for 30 minutes, then placed in an oven at 100°C for 72 hours. Following slow cooling, colorless, transparent bulk crystals were obtained, with a yield of approximately 90.32% (based on the amount of terbium nitrate hexahydrate). The unit cell parameters are... a = 10.7967 (1) Å, b = 11.7607 (2) Å, c = 14.2246 (2) Å, α = 75.745 (1) (deg), β = 74.563 (1)(deg), γ = 68.170 (1) (deg).

[0035] Figure 2 This is a structural diagram of the crystalline porous material Tb-PO, which has a porous three-dimensional structure formed by H3TPO linker chelate secondary building units (SBUs). The SBUs consist of eight twisted TPO... 3- Connectors link two LnO8 polyhedra. Each SBU contains Ln... 3+ Ions are respectively connected to six TPO 3- A linker and a terminal group coordinated DMA solvent molecule. TPO twisted in a Tb-PO structure. 3-The dihedral angles between the three benzene rings of the linker are 54.34°, 82.56°, and 77.88°, respectively.

[0036] Figure 3 Ligand coordination patterns and topological structures of Eu-PO and Tb-PO. Twisted and dynamic TPO structures within Eu-PO and Tb-PO structures. 3- The linker has only one coordination mode. μ 6- η 2 : η 1 : η 1 : η 1 : η 1 : η 1 Furthermore, both exhibit a 4,8-c topological connectivity and {4 12 0.6 12 0.8 4}{4 6 Connect the topological points of}2.

[0037] Example 3

[0038] Characterization analysis of crystalline porous materials Eu-PO and Tb-PO

[0039] Figure 4 The images show the powder X-ray diffraction (PXRD) patterns of the crystalline porous materials Eu-PO and Tb-PO. The experimental and simulated values ​​of the powder diffraction are in excellent agreement, proving that the crystalline porous materials Eu-PO and Tb-PO synthesized by the above method are both pure phases.

[0040] Figure 5 Images show scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HR-TEM) images of Eu-PO and Tb-PO. The images reveal that both Eu-PO and Tb-PO are clearly bulk crystals with very clean surfaces. Energy dispersive spectroscopy (EDS) measurements in HR-TEM mode show that Eu / Tb, C, N, O, and P elements exhibit a uniform distribution.

[0041] Figure 6Thermogravimetric analysis (TGA) plots are shown for the crystalline porous materials Eu-PO and Tb-PO. Thermal stability tests were conducted under a flowing nitrogen atmosphere, with the temperature slowly increased from 35 °C to 1000 °C at a rate of 5 °C / min. TGA analysis revealed that the guest molecules surrounding Eu-PO contained one DMA and one water molecule (theoretical value 13.97%, experimental value 13.52%). The guest molecules surrounding Tb-PO contained one DMA and two water molecules (theoretical value 15.80%, experimental value 14.90%). Upon further temperature increases above 600 °C, the framework of both Eu-PO and Tb-PO decomposed.

[0042] Example 4

[0043] Temperature-dependent photoluminescence spectroscopy of Eu-PO and Tb-PO

[0044] Using a steady-state transient fluorescence spectrometer (FLS1000) manufactured in Edinburgh, UK, variable-temperature emission spectra were performed on Eu-PO and Tb-PO in the temperature range of 80-460 K. Eu-PO and Tb-PO, which have the same structural connection, exhibited completely opposite intelligent response behaviors as the temperature increased.

[0045] like Figure 7 As shown, under excitation at 387 nm, the temperature-dependent emission spectrum of Eu-PO was tested in the temperature range of 80-460 K. When the temperature increased from 80 K to 460 K, the photoluminescence intensity of Eu-PO gradually increased with increasing temperature, exhibiting a temperature-dependent thermo-enhanced luminescence behavior. The intensity of the emission peak showed an excellent linear correlation with temperature (R0). 2 =0.984).

[0046] In stark contrast, the luminescence intensity of Tb-PO exhibits a significant thermal quenching behavior with increasing temperature, such as... Figure 8 As shown, under the excitation condition of 367 nm, the temperature-varying emission spectrum of Tb-PO in the temperature range of 80-460 K was obtained. The emission intensity of Tb-PO gradually decreases with increasing temperature, and the emission intensity also exhibits an excellent linear correlation with temperature (R0). 2 = 0.989).

[0047] Example 5

[0048] An in-depth exploration of the contrasting temperature-dependent luminescence behaviors of Eu-PO and Tb-PO with the same structural connections.

[0049] like Figure 9As shown, the single-crystal structures of Eu-PO were tested under different temperature conditions (100 K, 150 K, 200 K, 300 K, 373 K), and the TPO within the Eu-PO channels was analyzed. 3- The relationship between the twist angle of the molecular rotor module and temperature. As temperature increases, the TPO within the Eu-PO channels... 3- The included angles between the three benzene rings in the molecular rotor module are 54.61° / 82.05° / 76.46° (100K), 54.14° / 82.44° / 74.79° (150K), 54.49° / 81.32° / 74.40° (200K), 54.47° / 81.96° / 73.27° (300K), 57.64° / 88.66° / 72.00° (373 K), and 56.70° / 81.87° / 72.85° (373 K). Clearly, with increasing temperature, the TPO within the Eu-PO channels... 3- The torsion angles between the molecular rotor modules exhibited a clear and regular variation.

[0050] like Figure 10 As shown, the inventors also tested the temperature-dependent phosphorescence spectrum of Gd-PO in the range of 80-480 K. Within this temperature range, the temperature-dependent phosphorescence spectrum of Gd-PO exhibited a significant redshift (from 445 nm to 548 nm) with increasing temperature, demonstrating that the energy level of the lowest triplet state (T1) of the ligands within the Gd-PO structure significantly decreased with increasing temperature. When the temperature increased from 180 K to 480 K, the fluorescence intensity gradually increased with increasing temperature due to the thermally activated delayed fluorescence (TADF) effect.

[0051] The above results demonstrate that H3TPO can change the conformation and twisting of the molecular rotor under temperature-driven conditions, thereby exhibiting a dynamically changing T1 state energy level and inducing an elastic antenna effect.

[0052] like Figure 11 As shown, a schematic diagram illustrates the distinctly different temperature-dependent luminescence behaviors of Eu-PO and Tb-PO due to the dynamic changes in the T1 state energy level. According to Latva's rule of thumb, when the T1 state energy level of H3TPO is between 19500 and 22883 cm⁻¹... -1 It can efficiently sensitize Eu 3+ Characteristic luminescence of ions, and efficient sensitization of Tb 3+ The characteristic luminescence of ions requires the T1 state to have an energy level between 22500 and 22883 cm⁻¹. -1 Between. It is obvious that the energy level of the T1 state of H3TPO matches Eu. 3+The energy level range is much larger than Tb 3+ The significant difference in energy level matching range leads to opposite thermochromic luminescence behaviors in Eu-PO and Tb-PO, which have the same structural connections, in the temperature range of 80 K to 460 K: Eu-PO exhibits obvious thermally enhanced luminescence behavior, while Tb-PO exhibits obvious thermally quenched luminescence behavior.

[0053] Example 6

[0054] Tb-PO exhibits excellent X-ray scintillator performance.

[0055] like Figure 12 As shown, the Tb-PO and inorganic scintillator Bi4Ge3O were calculated using the XCOM database. 12 (BGO) in 1-10 8 The X-ray absorption coefficient in the photon energy range of keV was determined. The results indicate that Tb-PO possesses good X-ray absorption capability. Tb-PO exhibits a characteristic emission spectrum consistent with photoluminescence in X-ray radioluminescence testing, with a peak value of BGO (10000 Photons / MeV). -1 For reference, the light yield of Tb-PO is as high as 43372.1 Photons·MeV. -1 Tb-PO exhibits an excellent linear relationship between XEL intensity and X-ray dose, with a detection line as low as 20.22 nGy / s, which is far below the permissible radiation dose of 5.5 μGy / s for medical trials (a reduction of approximately 272 times).

[0056] As can be seen from the above embodiments, the present invention provides a porous crystalline material, its preparation method, and its application as a temperature-variable luminescent material. This porous crystalline material contains the ligand H3TPO, which is a dynamic molecular rotor module. The energy levels of its lowest excited singlet state (S1) and triplet state (T1) can be elastically tuned with temperature changes. This characteristic causes the isomorphic materials Eu-PO and Tb-PO to exhibit rare and diametrically opposed thermoluminescent behaviors. Specifically, the energy level range required for the optimal antenna effect of Eu(III) ions closely matches the dynamically and elastically varying T1 state energy level in H3TPO, thus endowing Eu-PO with significant "thermally enhanced luminescence" characteristics. In contrast, the dynamically and elastically varying T1 state energy level in H3TPO has a lower matching degree with the energy level range required for the optimal antenna effect of Tb(III) ions, leading to a significant "thermally quenched luminescence" phenomenon in Tb-PO. Furthermore, Tb-PO exhibits excellent performance as an X-ray scintillator: a light yield as high as 43,372.1 photons·MeV. -1The detection limit is as low as 20.22 nGy / s (272 times lower than the typical medical X-ray diagnostic dose (5.5 μGy / s)). This invention not only provides a new approach to modulating the energy levels of dynamic antennas to construct artificial intelligence luminescent materials, but also opens up new directions for developing high-performance X-ray scintillators based on Ln-MOFs.

[0057] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A porous crystalline material, characterized in that, The molecular formula of the porous crystalline material is: C 25 H 21 NO8PLn, where Ln is a europium ion or a terbium ion.

2. The porous crystalline material according to claim 1, characterized in that, When Ln is europium ion, the material is represented as Eu-PO with cell parameters a = 10.8175 (3) Å, b = 11.7886 (3) Å, c = 14.3357 (3) Å, α = 75.317 (2) (deg), β = 74.143 (2) (deg), γ = 68.352 (2) (deg).

3. The porous crystalline material according to claim 2, characterized in that, The Eu-PO is a porous three-dimensional structure formed by H3TPO linker chelating secondary building units (SBUs). SBUs consist of eight twisted TPOs 3- The connector connects two LnO8 polyhedra, and each SBU contains Ln 3+ Ions are respectively connected to six TPO 3- TPO with a linker and a terminal-coordinated solvent molecule twisted in the Eu-PO structure. 3- The dihedral angles between the three benzene rings of the linker are 54.61° / 82.05° / 76.46°, respectively; the twisted and dynamic TPO within the Eu-PO structure 3- The linker has only one coordination mode. μ 6- η 2 : η 1 : η 1 : η 1 : η 1 : η 1 It exhibits a 4,8-c topological connectivity and {4 12 0.6 12 0.8 4 }{4 6 Connect the topological points of}2.

4. The porous crystalline material according to claim 1, characterized in that, When Ln is a terbium ion, the material is represented as Tb-PO with cell parameters a = 10.7967 (1) Å, b = 11.7607 (2) Å, c = 14.2246 (2) Å, α = 75.745 (1) (deg), β = 74.563 (1) (deg), γ = 68.170 (1) (deg).

5. The porous crystalline material according to claim 4, characterized in that, The Tb-PO is a porous three-dimensional structure formed by H3TPO linker chelate secondary building units SBUs; SBUs consist of eight twisted TPOs 3- The connector connects two LnO8 polyhedra, and each SBU contains Ln 3+ Ions are respectively connected to six TPO 3- A linker and a terminal-coordinated DMA solvent molecule, TPO twisted in a Tb-PO structure. 3- The dihedral angles between the three benzene rings of the linker are 54.34°, 82.56°, and 77.88°, respectively.

6. The method for preparing the porous crystalline material according to any one of claims 1 to 5, characterized in that, Includes the following steps: The porous crystalline material is obtained by reacting 4,4',4''-phosphoryltribenzoic acid, europium nitrate, or terbium nitrate in a solvent and then cooling the mixture.

7. The preparation method according to claim 6, characterized in that, The molar ratio of the 4,4',4''-phosphoryltribenzoic acid to europium nitrate or terbium nitrate is 1:0.8~1.2; The solvent is water and N , N -A mixed solvent of dimethylacetamide, water and N , N The volume ratio of dimethylacetamide is 1:1~3.

8. The preparation method according to claim 7, characterized in that, The ratio of 4,4',4''-phosphoryltribenzoic acid to solvent is 0.05 mmol: 2~5 mL.

9. The preparation method according to claim 6, characterized in that, The reaction temperature is 90~110℃, and the reaction time is ≥48h.

10. The application of the porous crystalline material according to any one of claims 1 to 5 as a temperature-variable luminescent material.

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