Calixarene rare earth cluster fluorescent materials, their synthesis methods and applications

Abstract

The present invention provides calixarene rare earth cluster fluorescent materials, their synthesis methods and applications. The calixarene rare earth clusters of the present invention include at least two calixarene ligands and one rare earth metal oxygen cluster luminescent group. The calixarene ligands are located outside the luminescent group, and the rare earth metal oxygen cluster luminescent group is covered by calixarene coordination. The calixarene ligands and the rare earth metal oxygen cluster luminescent group are combined by coordination bonds to form a wrapped structure. The fluorescent materials prepared in the present invention containing double calixarene rare earth metal oxygen clusters have strong water stability, thermal quenching stability and radiation resistance stability and other properties without encapsulation or surface treatment, and have broad application prospects in high humidity and high radiation environments.

Description

Technical Field

[0001] The present invention belongs to the technical field of fluorescent materials, and particularly relates to calixarene rare earth cluster fluorescent materials, their synthesis methods and applications. Background Art

[0002] Lanthanide photoluminescent materials have been widely used in various aspects of our lives, such as lighting, display, clinical diagnosis, radiation detection and security detection. The special luminescent properties of rare earth (RE) ions (such as narrow emission bandwidth, long emission lifetime and small Stokes shift) make it possible for rare earth fluorescent materials to be applied in related fields. The photoluminescence properties of rare earth ions originate from the transition of 4f electrons and the shielding effect of the 5s 2 and 5p 6 shells. Although the luminescent properties of 4f-4f transitions have been widely studied, the study of the luminescence stability of lanthanide complexes under extreme conditions (such as in humid, high temperature and ultraviolet irradiation) is relatively less, and the research in this aspect is of great significance for the practical application of related materials.

[0003] A common problem in the application of lanthanide fluorescent materials is the attenuation of fluorescence intensity caused by humidity, high temperature or ultraviolet irradiation. For example, when exposed to a high humidity environment, water molecules coordinate with rare earth ions, and the vibration of water molecules causes vibrational quenching of the luminescence centers of rare earth ions, thereby causing attenuation of fluorescence intensity. To solve this problem, researchers have used different materials to encapsulate devices or phosphor materials, including poly(methyl acrylate), poly(vinylidene fluoride), polystyrene, silicone resin, Al2O3, zeolite-Y and silica, etc. (see references). Such encapsulation methods effectively slow down the diffusion of water molecules into the interior of the luminescence device under humid conditions, kinetically delay the binding of water molecules to the fluorescent material, and slow down the occurrence of vibrational quenching. However, the encapsulation strategy cannot prevent the coordination of solvent molecules (such as water molecules) thermodynamically, but only delays the occurrence of the reaction.

[0004] On the other hand, the above-mentioned encapsulation methods can only improve the fluorescence stability of fluorescent materials in a humid environment, and when the fluorescence properties of rare earth fluorescent materials are also affected by other adverse conditions (such as high temperature or long-term ultraviolet radiation), the improvement effect of the encapsulation strategy is relatively limited. The reason is that the decay of fluorescence properties caused by high temperature and radiation usually originates from the structural changes that occur during the application of the material, which cannot be solved by exogenous encapsulation methods. Therefore, designing the atomic environment of the lanthanide photoluminescence center is the key to solving the above various fluorescence stability problems. Summary of the Invention

[0005] The technical solution of the present invention is as follows:

[0006] A calixarene rare earth cluster, wherein the calixarene rare earth cluster includes at least a calixarene ligand and a luminescent group, the calixarene ligand is located outside the luminescent group, one luminescent group is covered by coordination of two calixarene ligands, and the calixarene ligand and the luminescent group are combined by a coordination bond to form a wrapped structure; wherein, the luminescent group is selected from rare earth metal oxygen clusters.

[0007] According to an embodiment of the present invention, the rare earth metal oxygen cluster includes at least one cluster, and each cluster contains at least one rare earth ion, preferably two or more rare earth ions. Exemplarily, the rare earth metal oxygen cluster is selected from a tetranuclear rare earth metal oxygen cluster and / or a nonanuclear rare earth metal oxygen cluster, wherein, the tetranuclear rare earth metal oxygen cluster means that each cluster contains four rare earth ions, and the nonanuclear rare earth metal oxygen cluster means that each cluster contains nine rare earth ions.

[0008] According to an embodiment of the present invention, the rare earth ion is provided by a rare earth element. Preferably, the rare earth element can be selected from the rare earth elements known in the art, such as at least one of Eu, Tb, Gd, Sm, etc.

[0009] According to an embodiment of the present invention, the rare earth element is provided by a rare earth salt. Preferably, the rare earth salt is selected from chlorides of rare earth elements, nitrates of rare earth elements, perchlorates of rare earth elements, hydroxides of rare earth elements, carbonates of rare earth elements.

[0010] Exemplarily, the rare earth salt is selected from Eu chloride, Eu nitrate, Eu perchlorate, Eu hydroxide, Eu carbonate.

[0011] Exemplarily, the rare earth salt is selected from Tb chloride, Tb nitrate, Tb perchlorate, Tb hydroxide, Tb carbonate.

[0012] Exemplarily, the rare earth salt is selected from Gd chloride, Gd nitrate, Gd perchlorate, Gd hydroxide, Gd carbonate.

[0013] According to an embodiment of the present invention, the calixarene ligand is provided by a residue of a calixarene analog. In the present invention, the residue refers to, for example, the group after the calixarene analog removes hydrogen ions.

[0014] Preferably, the calixarene analogues are selected from at least one of tetra-tert-butyl (tetrahydroxy) tetrathiacalix[4]arene (also known as 4-tert-butylthiacalix[4]arene, p-tert-Butylthiacalix[4]arene), monocarboxylatocalix[4]arene, p-dicarboxylatocalix[4]arene, p-tetracarboxylato-calix[4]arene, p-tetra m-(carboxyphenyl)-azocalix[4]arene, p-tetracyano-calix[4]arene, sulfonatocalix[n]arene, p-phosphonatocalix[4]arene, p-phosphineoxide-calix[4]arene. In the present invention, the dehydrogenation residue of p-tert-Butylthiacalix[4]arene is TC4A, the dehydrogenation residue of Monocarboxylatocalix[4]arene is MCC4A, the dehydrogenation residue of p-Tetracarboxylato-calix[4]arene is TCC4A, the dehydrogenation residue of p-Tetra m-(carboxyphenyl)-azocalix[4]arene is TMCAC4A, the dehydrogenation residue of p-Tetracyano-calix[4]arene is TCyC4A, the dehydrogenation residue of Sulfonatocalix[n]arene is SC4A, the dehydrogenation residue of p-Phosphonatocalix[4]arene is PC4A, and the dehydrogenation residue of p-Phosphineoxide-calix[4]arene is PPOC4A.

[0015] According to an embodiment of the present invention, the molecular formula of the calixarene rare earth cluster is [Ln a M b X c N d Q e ·nY; wherein,

[0016] M is selected from at least one of μ3-OH, μ4-OH, μ5-OH;

[0017] N is selected from at least one of -OCH3, -Cl, -OH, -OOCH;

[0018] Q is selected from at least one of DMA (dimethyl adipate), DMSO (dimethyl sulfoxide), DMF (N,N-dimethylformamide), HCOOH, H2O, CH3OH, CH3CH2OH;

[0019] X is selected from at least one of TC4A, TCC4A, TMCAC4A, TCyC4A, SC4A, PC4A, PPOC4A;

[0020] Y is selected from at least one of CH3OH, H2O, DMA, DMSO, DMF, CH3CH2OH;

[0021] a is an integer selected from 1 - 10, for example 4 or 9; b is an integer selected from 1 - 30, for example 1 or 10; c is an integer not less than 2, for example 2; d is an integer selected from 1 - 30, for example 1, 2; e is an integer selected from 1 - 30, for example 1.

[0022] According to an embodiment of the present invention, the calixarene rare earth cluster is a crystal or polycrystalline powder.

[0023] Preferably, in the structure of the crystal of the calixarene rare earth cluster, the rare earth metal oxygen cluster has an isolated structure, and the isolated structure means that the rare earth metal oxygen cluster exists independently in the crystal of the calixarene rare earth cluster.

[0024] Preferably, in the crystal of the calixarene rare earth cluster, the rare earth metal oxygen clusters are bridged by chemical bonds to form a chain-like structure, and the chain-like structures are preferably connected by hydrogen bonds to form a 1D-MOF structure.

[0025] According to an embodiment of the present invention, the calixarene rare earth cluster has fluorescence stability in a water-containing atmosphere and / or an oxygen-containing atmosphere. In the present invention, the water-containing atmosphere means that the water content in the atmosphere is 0.1-100 wt%, preferably 1-100 wt%, for example 100%. In the present invention, the oxygen-containing atmosphere means an atmosphere in the presence of oxidizing substances such as oxygen, ozone, nitrogen oxides, etc., wherein the oxygen content is 0.1-30 wt%, preferably 1-20 wt%, for example 20%. In the present invention, the fluorescence stability refers to at least one of water stability, thermal stability, and irradiation stability. Among them, the water stability means that the fluorescence emission intensity of the calixarene rare earth cluster after being soaked in water for 10 days is more than 50% of the original. Among them, the thermal stability means that the fluorescence emission intensity of the calixarene rare earth cluster after being placed at a temperature higher than 50 °C for 10 days is more than 50% of the original. Among them, the irradiation stability means that the fluorescence emission intensity of the calixarene rare earth cluster after being continuously irradiated with a 365 nm ultraviolet lamp for 10 days is more than 50% of the original. In the present invention, the calixarene rare earth cluster can achieve the above fluorescence stability without encapsulation or surface treatment.

[0026] According to an exemplary embodiment of the present invention, the calixarene rare earth cluster includes 2 calixarene ligands and 1 luminescent group. The calixarene ligands are located on the upper and lower sides of the luminescent group. The rare earth metal oxygen cluster is covered by calixarene coordination. The calixarene ligand and the luminescent group are combined by a coordination bond to form a wrapping structure; wherein, the luminescent group is selected from rare earth metal oxygen clusters.

[0027] According to a preferred embodiment of the present invention, the calixarene rare earth cluster includes at least 2 calixarene ligands and 1 tetranuclear rare earth metal oxygen cluster, and its chemical formula is [Ln4(μ4-OH)(TC4A)2(OCH3)2(DMF)2(HCOOH)2Cl2]·nCH3OH, where Ln is selected from Tb or Eu; n is selected from 0.1-1, for example 0.33, 0.66. Preferably, the tetranuclear rare earth metal oxygen cluster has an isolated structure.

[0028] According to an exemplary embodiment of the present invention, the chemical formula of the calixarene rare earth cluster is [Eu4(μ4-OH)(TC4A)2(OCH3)2(DMF)2(HCOOH)2Cl2]·0.33CH3OH, and its molecular weight is 2572.80 g / mol. Preferably, the crystal of the calixarene rare earth cluster belongs to the triclinic system, the space group is P-1, and the unit cell parameters are α = 69.3320(10)°, β = 83.0420(10)°, γ = 86.5600(10), Z = 2. Preferably, the calixarene rare earth cluster has red fluorescence. Preferably, the tetranuclear rare earth metal oxygen cluster has an isolated structure.

[0029] According to an exemplary embodiment of the present invention, the chemical formula of the calixarene rare earth cluster is [Tb4(μ4-OH)(TC4A)2(OCH3)2(DMF)2(HCOOH)2Cl2]·0.66CH3OH, and its molecular weight is 2618.24 g / mol. Preferably, the crystal of the calixarene rare earth cluster belongs to the triclinic system, the space group is P-1, and the unit cell parameters are α = 69.3000(10)°, β = 83.0000(10)°, γ = 86.5820(10), Z = 2. Preferably, the calixarene rare earth cluster has green fluorescence. Preferably, the tetranuclear rare earth metal oxygen cluster has an isolated structure.

[0030] According to a preferred embodiment of the present invention, the calixarene rare earth cluster at least includes a calixarene ligand and a tetranuclear rare earth metal oxygen cluster. Optionally, the tetranuclear rare earth metal oxygen clusters form a chain structure, and the chain structures are connected by hydrogen bonds to form a 1D-MOF structure. Its chemical formula is {Ln4(μ4-OH)(TC4A)2(H2O)2(CH3O)(HCOO)2(HCOOH)}·nCH3OH, where Ln is selected from Tb or Eu; n is selected from 1-10, for example 1 or 5; the tetranuclear rare earth metal oxygen clusters are bridged by chemical bonds to form a chain structure.

[0031] According to an exemplary embodiment of the present invention, the chemical formula of the calixarene rare earth cluster is {Tb4(μ4-OH)(TC4A)2(H2O)2(CH3O)(HCOO)2(HCOOH)}·CH3OH, and its molecular weight is 2319.82 g / mol. Preferably, the crystal of the calixarene rare earth cluster belongs to the orthorhombic system, its space group is Pnma, and its unit cell parameters are Z = 4. Preferably, in the crystal of the calixarene rare earth cluster, the tetranuclear rare earth metal oxygen clusters are bridged by chemical bonds to form a chain structure, and the chain structures are connected by hydrogen bonds to form a 1D-MOF structure. Preferably, the calixarene rare earth cluster has green fluorescence.

[0032] According to an exemplary embodiment of the present invention, the chemical formula of the calixarene rare earth cluster is {Eu4(μ4-OH)(TC4A)2(H2O)2(CH3O)(HCOO)2(HCOOH)}·5CH3OH, and its molecular weight is 2420.14 g / mol. Preferably, the crystal of the calixarene rare earth cluster belongs to the orthorhombic system, the space group is Pnma, and the unit cell parameters are Z = 4. Preferably, in the crystal of the calixarene rare earth cluster, the tetranuclear rare earth metal oxygen clusters are bridged by chemical bonds to form a chain structure, and the chain structures are connected by hydrogen bonds to form a 1D-MOF structure. Preferably, the calixarene rare earth cluster has red fluorescence.

[0033] According to a preferred embodiment of the present invention, the calixarene rare earth cluster comprises at least 2 calixarene ligands and 1 nonanuclear rare earth metal oxygen cluster, and its chemical formula is [Ln9(μ5-OH)2(μ3-OH)8(OCH3)(TC4A)2(H2O) 24 Cl8]·nCH3OH, wherein, Ln is selected from Tb or Eu; n is selected from 1-10, for example 2.6. Preferably, the nonanuclear rare earth metal oxygen cluster has an isolated structure.

[0034] According to an exemplary embodiment of the present invention, the chemical formula of the calixarene rare earth cluster is [Tb9(μ5-OH)2(μ3-OH)8(OCH3)(TC4A)2(H2O) 24 Cl8]·2.6CH3OH, and its molecular weight is 3703.03 g / mol. Preferably, the crystal of the calixarene rare earth cluster belongs to the tetragonal system, the space group is P4 / nnc, and the unit cell parameters are Z = 2. Preferably, the calixarene rare earth cluster has green fluorescence. Preferably, the nonanuclear rare earth metal oxygen cluster has an isolated structure.

[0035] According to a preferred embodiment of the present invention, the calixarene rare earth cluster comprises at least a calixarene ligand and a nonanuclear rare earth metal oxygen cluster, and the rare earth metal oxygen clusters are optionally bridged by chemical bonds to form a chain structure, and the chain structures are connected by hydrogen bonds to form a 1D-MOF structure, and its chemical formula is {Ln9(μ5-OH)2(μ3-OH)8(TC4A)2(HCOO)7(H2O) 10 (OCH2CH3)2}·nCH3CH2OH, wherein, Ln is selected from Tb or Eu; n is selected from 1-10, for example 5.86.

[0036] According to an exemplary embodiment of the present invention, the chemical formula of the calixarene rare earth cluster is {Tb9(μ5-OH)2(μ3-OH)8(TC4A)2(HCOO)7(H2O) 10 (OCH2CH3)2}·CH3CH2OH, n = 5.86, and its molecular weight is 3811.61 g / mol. Preferably, the crystal of the calixarene rare earth cluster belongs to the monoclinic system, the space group is P4 / nnc, and the unit cell parameters are Z = 4. Preferably, in the crystal of the calixarene rare earth cluster, the nonanuclear rare earth metal oxygen clusters are bridged by chemical bonds to form a chain structure, and the chain structures are connected by hydrogen bonds to form a 1D-MOF structure. Preferably, the calixarene rare earth cluster has green fluorescence.

[0037] In the present invention, the fluorescence of the calixarene rare earth cluster is obtained by excitation under light conditions known in the art, for example, at 547 nm.

[0038] The present invention also provides a method for synthesizing the above-mentioned calixarene rare earth cluster. The synthesis method includes placing a rare earth salt and a calixarene analog in a solvent, and the calixarene rare earth cluster can be prepared by a hydrothermal method or a solvothermal method.

[0039] According to an exemplary embodiment of the present invention, the synthesis method is as Figure 1 shown.

[0040] According to an embodiment of the present invention, the rare earth salt and the calixarene analog have the meanings as described above.

[0041] According to an embodiment of the present invention, the molar ratio of the rare earth salt to the calixarene analog is (0.1 - 10):1, preferably (1 - 5):1, for example, 1:1, 2:1, 3:1.

[0042] According to an embodiment of the present invention, the solvent is selected from at least one of methanol, acetonitrile, DMF, DMA, DME, and H2O. Exemplarily, the solvent is selected from a mixed solvent of methanol and DMF with a volume ratio of 3:1.

[0043] According to an embodiment of the present invention, the present invention does not specifically limit the amount of the solvent used, as long as the solvothermal reaction can be carried out. Exemplarily, the molar volume ratio of the rare earth salt to the solvent is 0.01 - 0.1 mmol:1 - 10 ml, for example, 0.03 mmol:7 ml.

[0044] According to an embodiment of the present invention, the solvothermal method can be carried out using equipment known in the art, for example, a hydrothermal reaction kettle, and its inner lining is, for example, polytetrafluoroethylene.

[0045] According to an embodiment of the present invention, the conditions of the solvothermal method include: maintaining the temperature at 80 - 180 °C for 1 - 50 h and then cooling down. Preferably, the cooling down includes cooling down at a cooling rate of 1 - 5 °C / h. In the present invention, the formation of crystals is controlled by controlling the cooling rate. When the cooling rate is 1 - 5 °C / h, the quality of the crystals is better and the yield is also greatly improved; while when the cooling rate is greater than 5 °C / h (for example, greater than 10 °C / h), the quality of the crystals is poor and the yield is also significantly reduced, and even crystals cannot be prepared. Exemplarily, maintain the temperature at 120 °C, 130 °C, 140 °C, 150 °C or 160 °C for 48 h, and then cool down to room temperature at a cooling rate of 3 °C / h.

[0046] According to an embodiment of the present invention, the synthesis method further includes washing after obtaining a solid by the solvothermal method.

[0047] Preferably, the solid can be obtained by methods known in the art, such as filtration or evaporation. Preferably, the washing can be carried out by methods known in the art, such as washing with the solvent. Exemplarily, it is washed with a mixed solution of methanol and DMF (volume ratio 1:1).

[0048] The present invention also provides a fluorescent material, which comprises the above-mentioned calixarene rare earth cluster.

[0049] The present invention also provides the application of the above-mentioned calixarene rare earth cluster and / or fluorescent material in the fields of lighting, display, clinical diagnosis, radiation detection or safety detection, etc.

[0050] Advantageous Effects

[0051] The present invention adopts the method of double-ligand coordination protection. By coordinating and protecting the luminescence center of the rare earth metal oxygen cluster with calixarene, a double-calixarene rare earth metal oxygen cluster is obtained, which exhibits excellent fluorescence stability as a fluorescent material, such as water stability, high-temperature stability, ultraviolet light aging stability, etc.

[0052] Significantly different from the traditional surface coating and surface modification technologies, the present invention prepares a fluorescent material containing a double-calixarene rare earth metal oxygen cluster. By using a calixarene ligand with hydrophobic properties to form a strong coordination bond with the luminescence group of the rare earth metal oxygen cluster, its structural stability can be significantly improved. The fluorescent material containing a double-calixarene rare earth metal oxygen cluster prepared by the present invention has strong water stability, thermal quenching stability and radiation resistance stability, etc. without encapsulation or surface treatment, and has broad application prospects in high-humidity and high-radiation environments. Description of the Drawings

[0053] Figure 1 It is a schematic diagram of the synthesis process of the calixarene rare earth cluster.

[0054] Figure 2 It is a schematic diagram of the structure of the fluorescent material crystal 1.

[0055] Figure 3 It is a schematic diagram of the structure of the fluorescent material crystal 4.

[0056] Figure 4 It is a schematic diagram of the structure of the fluorescent material crystal 5.

[0057] Figure 5 It is a schematic diagram of the structure of the fluorescent material crystal 6.

[0058] Figure 6 It is the stability test of the fluorescent material crystal 2.

[0059] Figure 7 It is the test result of the white light LED device in Application Example 1.

[0060] Figure 8 It is for the water stability test of the fluorescent material crystals 4 (a-c) and crystal 5 (d-f).

[0061] Figure 9 It is for the thermal stability and irradiation stability test of the fluorescent material crystal 4. Specific implementation mode

[0062] The technical solution of the present invention will be further described in detail below in conjunction with specific embodiments. It should be understood that the following embodiments are only illustrative explanations of the present invention and should not be construed as limiting the protection scope of the present invention. All technologies implemented based on the above content of the present invention are covered within the scope of protection intended by the present invention.

[0063] Unless otherwise specified, the raw materials and reagents used in the following embodiments are all commercially available products or can be prepared by known methods.

[0064] Example 1

[0065] The synthesis method of the bis-calixarene coordinated tetra-nuclear rare earth metal oxygen cluster is as follows:

[0066] A mixture of H4TC4A (0.074 g, 0.10 mmol), 2-mercaptonicotinic acid (H2mna) (0.017 g, 0.11 mmol), TbCl3·6H2O (0.11 g, 0.30 mmol), MeOH (3.5 mL) and DMF (3.5 mL) was placed in the polytetrafluoroethylene liner of a 23 mL stainless steel autoclave, kept at 130 °C for 7 days, and then cooled to 30 °C at a rate of 3 °C / h. The colorless block crystals were separated by filtration, washed with 1:1 MeOH-DMF, and dried to obtain the fluorescent material crystal 1.

[0067] The tetra-nuclear chain-like green fluorescent material crystal 1 prepared in this example has the chemical formula {Tb4(μ4-OH)(TC4A)2(H2O)2(CH3O)(HCOO)2(HCOOH)}·CH3OH, with a molecular weight of 2319.82 g / mol, belonging to the orthorhombic system, space group Pnma, and unit cell parameters of Z = 4.

[0068] The crystal structure of the fluorescent material crystal 1 in this example is a chain-like structure formed by bridging of formate groups between tetra-nuclear rare earth metal oxygen clusters. The tetra-nuclear rare earth metal oxygen clusters are all wrapped by ligands with strong coordination ability such as TC4A, -OCH3, and DMF, H2O, -OOCH, HCOOH, etc. to form a shell-like wrapping structure. The structural schematic diagram of the fluorescent material crystal 1 is as Figure 2As shown, the chain structures are connected by hydrogen bonds to form a one-dimensional chain-like metal-organic framework (1D-MOF) structure. This crystal has a stable coordination mode, with excellent water stability, thermal quenching stability, and anti-irradiation stability.

[0069] Example 2

[0070] The synthesis method of the double-calixarene coordinated tetranuclear rare-earth metal-oxygen cluster is as follows:

[0071] A mixture of H4TC4A (0.074 g, 0.10 mmol), 2-mercaptonicotinic acid (H2mna) (0.017 g, 0.11 mmol), EuCl3·6H2O (0.15 g, 0.30 mmol), MeOH (3.5 mL), and DMF (3.5 mL) was placed in the PTFE liner of a 23 mL stainless-steel autoclave, kept at 130 °C for 7 days, and then cooled to 30 °C at a rate of 3 °C / h. The colorless block crystals were separated by filtration, washed with 1:1 MeOH-DMF, and dried to obtain the fluorescent material crystal 2.

[0072] The tetranuclear chain-like red fluorescent material crystal 2 prepared in this example has the chemical formula {Eu4(μ4-OH)(TC4A)2(H2O)2(CH3O)(HCOO)2(HCOOH)}·5CH3OH, with a molecular weight of 2420.14 g / mol. It belongs to the orthorhombic system, the space group is Pnma, and the unit cell parameters are Z = 4.

[0073] The crystal structure of the fluorescent material crystal 2 in this example is similar to that of the fluorescent material crystal 1 in Example 1. The chains are connected by hydrogen bonds to form a 1D-MOF structure. This crystal has a stable coordination mode, with excellent water stability, thermal quenching stability, and anti-irradiation stability.

[0074] Example 3

[0075] Synthesis method of isolated double-calixarene coordinated tetranuclear rare-earth metal-oxygen cluster:

[0076] A mixture of EuCl3·6H2O (0.86 g, 2.36 mmol) and H4TC4A (0.28 g, 0.38 mmol) was dissolved in a mixed solvent of MeOH and DMF (24 ml, v:v = 1:1). The solution was stirred at room temperature for 5 hours, and then triethylamine (60 μl) was added. The solution was sealed in the PTFE liner of a 50 mL autoclave, kept at 140 °C for two days, and then slowly cooled to 30 °C at a rate of about 3 °C / h. The colorless block crystals were separated by filtration, then washed with 1:1 MeOH / DMF and dried in air to obtain the fluorescent material crystal 3.

[0077] The red fluorescent material crystal 3 prepared in this example has the chemical formula [Eu4(μ4-OH)(TC4A)2(OCH3)2(DMF)2(HCOOH)2Cl2]·0.33CH3OH, a molecular weight of 2572.80 g / mol, belongs to the triclinic system, the space group is P-1, and the unit cell parameters are α = 69.3320(10)°, β = 83.0420(10)°, γ =

[0078] 86.5600(10), Z = 2.

[0079] Example 4

[0080] Synthesis method of isolated double-calixarene coordinated tetranuclear rare-earth metal-oxygen clusters: Dissolve a mixture of TbCl3·6H2O (0.88 g, 2.36 mmol) and H4TC4A (0.28 g, 0.38 mmol) in a mixed solvent of MeOH and DMF (24 ml, v:v = 1:1). Stir the solution at room temperature for 5 hours, and then add triethylamine (60 ul). Seal the solution in the polytetrafluoroethylene liner of a 50 mL autoclave, keep it at 140 °C for two days, and then slowly cool it to 30 °C at a rate of about 3 °C / h. Separate the colorless block crystals by filtration, then wash them with 1:1 MeOH / DMF and dry them in air to obtain the fluorescent material crystal 4.

[0081] The green fluorescent material crystal 4 prepared in this example has the chemical formula [Tb4(μ4-OH)(TC4A)2(OCH3)2(DMF)2(HCOOH)2Cl2]·0.66CH3OH, a molecular weight of 2618.24 g / mol, belongs to the triclinic system, the space group is P-1, and the unit cell parameters are α = 69.3000(10)°, β = 83.0000(10)°, γ = 86.5820(10), Z = 2.

[0082] The crystal structure of the fluorescent material crystal 4 in this example is the structure of isolated tetranuclear rare-earth metal-oxygen clusters. Figure 3 As shown in the structure schematic diagram of the fluorescent material crystal 4, the periphery of the tetranuclear rare-earth metal-oxygen clusters is wrapped by ligands with strong coordination ability such as TC4A, -OCH3, DMF, and HCOOH to form a shell-like wrapping structure, which brings about super strong water stability, thermal quenching stability, and anti-irradiation stability.

[0083] The fluorescent material crystal 3 and the fluorescent material crystal 4 have similar crystal structures.

[0084] Example 5

[0085] Synthesis method of isolated double - calixarene coordinated nonanuclear rare - earth metal - oxygen cluster: A mixture of TbCl3·6H2O (0.2139 g, 0.58 mmol) and H4TC4A (0.691 g, 0.10 mmol) was dissolved in 6 mL of MeOH and DMF (1:1, v / v) and stirred at room temperature for 10 h. TEA (20 μL) was added to the solution, and then it was loaded into a 23 - mL Teflon - lined autoclave. The Teflon - lined autoclave was heated at 130 °C for two days, and then slowly cooled to 30 °C at a rate of about 3 °C / h, filtered, and the filtrate was volatilized at room temperature for 2 weeks to obtain the fluorescent crystal material 5.

[0086] The green fluorescent material crystal 5 prepared in this example has the chemical formula [Tb9(μ5 - OH)2(μ3 - OH)8(OCH3)(TC4A)2(H2O) 24 Cl8]·2.6CH3OH, with a molecular weight of 3703.03 g / mol, belonging to the tetragonal system, space group P4 / nnc, and the unit - cell parameters are Z = 2.

[0087] The structural schematic diagram of the fluorescent material crystal 5 is as Figure 4 shown, which is the structure of an isolated nonanuclear rare - earth metal - oxygen cluster. The nonanuclear rare - earth metal - oxygen cluster is surrounded by ligands such as TC4A, - OCH3, and H2O with strong coordination ability to form a shell - like encapsulation structure. It has a double - cone structure, which brings about super strong water stability, thermal - quenching stability, and anti - irradiation stability.

[0088] Example 6

[0089] Synthesis method of interconnected double - calixarene coordinated nonanuclear rare - earth metal - oxygen cluster: A mixture of Tb(ClO4)3 (1 mol / L, 3 ml), Ni(NO3)2·6H2O (0.3431 g, 1.20 mmol), 2 - hydroxy succinic acid (0.0911, 0.68 mmol), and 5 - mercapto - 1 - methyltetrazole (0.0847 g, 0.73 mmol) was dissolved in a mixed solvent of CH3CH2OH (8 ml), N - methylformamide (2 ml), and H2O (500 μl). The mixed solution was stirred at room temperature for 5 h and filtered. Then H4TC4A (0.0433 g, 0.06 mmol) was added and encapsulated in the Teflon liner of a 23 - mL stainless - steel autoclave, and heated at 160 °C for 4 days. The system was cooled to room temperature at a rate of 3 °C / h, filtered, and the filter residue was washed with absolute ethanol to obtain the fluorescent crystal material 6.

[0090] The green fluorescent material crystal 6 prepared in this example has a chemical formula of

[0091] {Tb9(μ5-OH)2(μ3-OH)8(TC4A)2(HCOO)7(H2O) 10 (OCH2CH3)2}·CH3CH2OH, with a molecular weight of 3811.61 g / mol, belonging to the monoclinic system, space group P4 / nnc, and unit cell parameters of Z = 4.

[0092] The structural schematic diagram of the fluorescent material crystal 6 is as shown in Figure 5 Shown, its crystal structure is a chain structure formed by bridging between nine-nuclear rare-earth metal oxygen clusters through formate ligands. The nine-nuclear rare-earth metal oxygen clusters are all wrapped by ligands with strong coordination abilities such as TC4A, H2O, -OOCH, and -OCH2CH3 to form a shell-like wrapping structure. The structural schematic diagram of the fluorescent material crystal 6 is as shown in Figure 5 Shown, the chain structures are connected by hydrogen bonds to form a 1D-MOF structure. This crystal has a stable coordination mode, with excellent water stability, thermal quenching stability, and anti-irradiation stability.

[0093] Test Example 1

[0094] (1) Water stability test: The fluorescent material crystal 2 prepared in Example 2 was soaked in water for 0 days, 5 days, 10 days, 15 days, and 20 days respectively, and its fluorescence emission intensity was measured.

[0095] (2) Thermal stability test: The fluorescent material crystal 2 prepared in Example 2 was continuously irradiated under light at 547 nm for 0 days, 5 days, 10 days, and 15 days respectively, and its fluorescence emission intensity was measured.

[0096] (3) Anti-irradiation stability test: The fluorescent material crystal 2 prepared in Example 2 was continuously irradiated at 50 °C, 75 °C, 100 °C, 125 °C, 150 °C, 175 °C, 200 °C, 225 °C, 250 °C, and 275 °C for 10 days respectively, and its fluorescence emission intensity was measured.

[0097] As shown in Figure 6 Shown, the fluorescent material crystal 2 has strong water stability, and can still maintain 96.5% of its previous fluorescence emission after being soaked in water for 10 days, and can still maintain 94.5% of its original fluorescence emission at 150 °C. Moreover, this material shows strong ultraviolet radiation stability, and its emission intensity can still maintain 92.7% of its original value after 10 days of continuous irradiation. That is to say, this material realizes the perfect unity of water stability, thermal stability, and anti-irradiation stability.

[0098] Application Example 1

[0099] The white light LED device made of the fluorescent material crystal 2 prepared in Example 2 is composed of Figure 7 As can be seen, this white light LED device has the characteristics of a relatively long service life (continuous operation for at least two weeks) and a relatively large color gamut range (75%).

[0100] The white light LED devices prepared from the fluorescent material crystals 1 and 6 of Examples 1 and 6 also basically have the above properties.

[0101] Test Example 2

[0102] (1) Water stability test: Take the fluorescent material crystals 4 and 5 of Examples 4 and 5, soak them in water for 10 days respectively, and test their fluorescence emission intensity.

[0103] (2) Thermal stability test: Take the fluorescent material crystal 4 of Example 4 and irradiate it continuously under light of 547 nm for 0 days, 5 days, 10 days, and 15 days respectively, and test its fluorescence emission intensity.

[0104] (3) Anti-irradiation stability test: Take the fluorescent material crystal 4 prepared in Example 4 and irradiate it continuously at 50 °C, 75 °C, 100 °C, 125 °C, 150 °C, 175 °C, 200 °C, 225 °C, 250 °C, and 275 °C for 10 days respectively, and test its fluorescence emission intensity.

[0105] As Figure 8 shown in a-c, the fluorescent material crystal 4 can still maintain 98% of its original emission intensity after being soaked in water for 10 days; the contact angle of the fluorescent material crystal 4 is 126°; as Figure 8 shown in d-f, the emission intensity of the fluorescent material crystal 5 still remains 60% of its original value after being soaked in water for 10 days; the contact angle of the fluorescent material crystal 5 is 101°. It can be seen from this that the calixarene rare earth cluster prepared by the present invention has good anti-deliquescence performance.

[0106] As Figure 9 shown in a-d, the fluorescent material crystal 4 also shows strong fluorescence stability at high temperatures, and can still maintain 92.1% of its fluorescence emission intensity at 150 °C; after being continuously irradiated with a 365 nm ultraviolet lamp for 10 days, its emission intensity can still maintain 93% of its original value. It can be seen from this that the fluorescent material crystal 4 is a phosphor material with stable luminescence performance.

[0107] Application Example 2

[0108] Take the white light LED device made of the fluorescent material crystal 4 prepared in Example 4. The white light LED device made of the fluorescent material crystal 4 has the characteristics of a relatively long service life (continuous operation for at least two weeks) and a relatively large color gamut range (74.3%).

[0109] The white LED devices prepared from the fluorescent material crystals 3 and 5 of Examples 3 and 5 also basically have the above-mentioned properties.

[0110] In summary, the present invention prepares a unified fluorescent material crystal with strong photoluminescence performance and stable luminescence performance by coordinating calixarene ligands and rare earth luminescent groups, showing excellent fluorescence stability and strong hydrophobicity. The calixarene rare earth cluster prepared by the present invention has ultra-strong stable luminescence performance, and can be used as a fluorescent material in light-emitting devices.

[0111] The above describes the exemplary embodiments of the present invention. However, the protection scope of this application is not limited to the above embodiments. Any modifications, equivalent replacements, improvements, etc. made by those skilled in the art within the spirit and principles of the present invention shall be included in the protection scope of the present invention.

Claims

1. A calixarene rare earth cluster, characterized in that, The calixarene rare earth cluster includes at least a calixarene ligand and a luminescent group. The calixarene ligand is located outside the luminescent group, and the luminescent group is covered by two calixarene coordinations. The calixarene ligand and the luminescent group are combined by a coordination bond to form a wrapped structure. Among them, the luminescent group is selected from rare earth metal oxygen clusters; The molecular formula of the calixarene rare earth cluster is [Ln a M b X c N d Q e ·nY; wherein, M is selected from μ 3-OH, μ 4-OH, μ at least one of 5-OH; N is selected from at least one of -OCH3, -Cl, -OH, -OOCH; Q is selected from at least one of DMA, DMSO, DMF, HCOOH, H2O, CH3OH, CH3CH2OH; X is selected from at least one of TC4A, TCC4A, TMCAC4A, TCyC4A, SC4A, PC4A, PPOC4A; TC4A is the dehydrogenation residue of tetra-tert-butyl(tetrahydroxy)tetrathiacalix[4]arene, TCC4A is the dehydrogenation residue of p-tetracarboxycalix[4]arene, TMCAC4A is the dehydrogenation residue of p-tetra-m-(carboxyphenyl)-azacalix[4]arene, TCyC4A is the dehydrogenation residue of p-tetracyano-calix[4]arene, SC4A is the dehydrogenation residue of sulfocalix[n]arene, PC4A is the dehydrogenation residue of p-phosphocalix[4]arene, and PPOC4A is the dehydrogenation residue of p-phosphine oxide-calix[4]arene; Y is selected from at least one of CH3OH, H2O, DMA, DMSO, DMF, CH3CH2OH; a is an integer selected from 1 to 10; b is an integer selected from 1 to 30; c is an integer not less than 2; d is an integer selected from 1 to 30; e is an integer selected from 1 to 30.

2. The calixarene rare earth cluster according to claim 1, wherein The rare earth metal oxygen cluster includes at least one cluster, and each cluster contains at least one rare earth element ion; The rare earth element ion is provided by a rare earth element; the rare earth element is selected from at least one of Eu, Tb, Gd, Sm; The rare earth element is provided by a rare earth salt; the rare earth salt is selected from the chloride of the rare earth element, the nitrate of the rare earth element, the perchlorate of the rare earth element, the hydroxide of the rare earth element, the carbonate of the rare earth element; The calixarene ligand is provided by the residue of a calixarene analog.

3. The calixarene rare earth cluster according to claim 2, wherein, The rare earth salt is selected from the chloride of Eu, the nitrate of Eu, the perchlorate of Eu, the hydroxide of Eu, the carbonate of Eu; The rare earth salt is selected from the chloride of Tb, the nitrate of Tb, the perchlorate of Tb, the hydroxide of Tb, the carbonate of Tb; The rare earth salt is selected from the chloride of Gd, the nitrate of Gd, the perchlorate of Gd, the hydroxide of Gd, the carbonate of Gd; The calixarene analogs are selected from at least one of tetra-tert-butyl(tetrahydroxy)tetrathiacalix[4]arene, monocarboxycalix[4]arene, p-dicarboxycalix[4]arene, p-tetracarboxycalix[4]arene, p-tetra-m-(carboxyphenyl)-azacalix[4]arene, p-tetracyano-calix[4]arene, sulfocalix[n]arene, p-phosphocalix[4]arene, p-phosphine oxide-calix[4]arene; 4. The calixarene rare earth cluster according to claim 1, characterized in that, The calixarene rare earth cluster is a crystal or polycrystalline powder; In the crystal structure of the calixarene rare earth cluster, the rare earth metal-oxygen cluster has an isolated structure, and the isolated structure means that the rare earth metal-oxygen cluster exists independently in the crystal of the calixarene rare earth cluster; In the crystal of the calixarene rare earth cluster, the rare earth metal-oxygen clusters are bridged by chemical bonds to form a chain-like structure, and the chain-like structures are connected by hydrogen bonds to form a 1D-MOF structure; The calixarene rare earth cluster includes 2 calixarene ligands and 1 luminescent group. The calixarene ligands are located on the upper and lower sides of the luminescent group. The rare earth metal-oxygen cluster is covered by calixarene coordination. The calixarene ligand and the luminescent group are combined by a coordination bond to form a wrapping structure; wherein, the luminescent group is selected from the rare earth metal-oxygen cluster.

5. The calixarene rare earth cluster according to claim 1, wherein The calixarene rare earth cluster comprises at least 2 calixarene ligands and 1 four-nuclear rare earth metal oxygen cluster, and its chemical formula is [Ln4( μ 4-OH)(TC4A)2(OCH3)2(DMF)2(HCOOH)2Cl2]·nCH3OH, wherein, Ln is selected from Tb or Eu; n is selected from 0.1-1; The tetranuclear rare earth metal-oxygen cluster has an isolated structure.

6. The calixarene rare earth cluster according to claim 5, wherein The chemical formula of the calixarene rare earth cluster is [Eu4( μ 4-OH)(TC4A)2(OCH3)2(DMF)2(HCOOH)2Cl2]·0.33CH3OH, its molecular weight is 2572.80 g / mol, and its crystal belongs to the triclinic system with the space group P-1 , and the unit cell parameters are a = 12.2472(3) Å, b = 20.8833(5) Å, c = 22.7770(5) Å, α = 69.3320(10)°, β = 83.0420(10)°, γ = 86.5600(10), Z = 2; the crystal of the calixarene rare earth cluster has red fluorescence.

7. The calixarene rare earth cluster according to claim 5, wherein The chemical formula of the calixarene rare earth cluster is [Tb4( μ 4-OH)(TC4A)2(OCH3)2(DMF)2(HCOOH)2Cl2]·0.66CH3OH, its molecular weight is 2618.24 g / mol, and its crystal belongs to the triclinic system with the space group of P-1 , and the unit cell parameters are a = 12.2571(3) Å, b = 20.9533(5) Å, c = 22.7770(5) Å, α = 69.3000(10)°, β = 83.0000(10)°, γ = 86.5820(10), Z = 2; the calixarene rare earth cluster has green fluorescence.

8. The calixarene rare earth cluster according to claim 1, characterized in that, The calixarene rare earth cluster at least includes a calixarene ligand and a tetranuclear rare earth metal oxygen cluster. The tetranuclear rare earth metal oxygen cluster optionally forms a chain structure, and the chain structures are connected by hydrogen bonds to form a 1D-MOF structure, and its chemical formula is {Ln4( μ 4-OH)(TC4A)2(H2O)2(CH3O)(HCOO)2(HCOOH)}·nCH3OH, where Ln is selected from Tb or Eu; n is selected from 1-10; the tetranuclear rare earth metal oxygen clusters are bridged by chemical bonds to form a chain structure.

9. The calixarene rare earth cluster according to claim 8, characterized in that, The chemical formula of the calixarene rare earth cluster is {Tb4( μ 4-OH)(TC4A)2(H2O)2(CH3O)(HCOO)2(HCOOH)}·CH3OH, its molecular weight is 2319.82 g / mol, its crystal belongs to the orthorhombic system, and its space group is Pnma , and its unit cell parameters are a = 19.7842(4) Å, b = 36.0171(8) Å, c = 14.0930(2) Å, Z = 4; the calixarene rare earth cluster has green fluorescence.

10. The calixarene rare earth cluster according to claim 8, characterized in that, The chemical formula of the calixarene rare earth cluster is {Eu4( μ 4-OH)(TC4A)2(H2O)2(CH3O)(HCOO)2(HCOOH)}·5CH3OH, its molecular weight is 2420.14 g / mol, its crystal belongs to the orthorhombic system, and the space group is Pnma , and the unit cell parameters are a = 19.8907(17) Å, b = 36.1920(3) Å, c = 13.9547(12) Å, Z = 4; the calixarene rare earth cluster has red fluorescence.

11. The calixarene rare earth cluster according to claim 1, characterized in that, The calixarene rare earth cluster comprises at least 2 calixarene ligands and 1 nonanuclear rare earth metal oxygen cluster, and its chemical formula is [Ln9( μ 5-OH)2( μ 3-OH)8(OCH3)(TC4A)2(H2O) 24 Cl8]·nCH3OH, wherein, Ln is selected from Tb or Eu; n is selected from 1-10; the nonanuclear rare earth metal oxygen cluster has an isolated structure.

12. The calixarene rare earth cluster according to claim 11, wherein The chemical formula of the calixarene rare earth cluster is [Tb9( μ 5-OH)2( μ 3-OH)8(OCH3) (TC4A)2(H2O) 24 Cl8]·2.6CH3OH. Its molecular weight is 3703.03 g / mol. Its crystal belongs to the tetragonal system, and the space group is P 4 / nnc . The unit cell parameters are a = 13.3479(4) Å, b = 13.3479(4) Å, c = 46.0809(18) Å, Z = 2. The calixarene rare earth cluster has green fluorescence.

13. The calixarene rare earth cluster according to claim 1, wherein The calixarene rare earth cluster at least comprises a calixarene ligand and a nonanuclear rare earth metal oxygen cluster. Optionally, the rare earth metal oxygen clusters are bridged by chemical bonds to form a chain structure, and the chain structures are connected by hydrogen bonds to form a 1D-MOF structure, and its chemical formula is {Ln9( μ 5-OH)2( μ 3-OH)8(TC4A)2(HCOO)7(H2O) 10 (OCH2CH3)2}·nCH3CH2OH, wherein Ln is selected from Tb or Eu; and n is selected from 1-10.

14. The calixarene rare earth cluster according to claim 13, characterized in that, The chemical formula of the calixarene rare earth cluster is {Tb9( μ 5-OH)2( μ 3-OH)8(TC4A)2(HCOO)7(H2O) 10 (OCH2CH3)2}·CH3CH2OH, its molecular weight is 3811.61 g / mol, its crystal belongs to the monoclinic system, and the space group is P 4 / nnc , the unit cell parameters are a = 47.2782(15) Å, b =14.0449(6) Å, c =19.6661(6) Å, Z = 4; the calixarene rare earth cluster has green fluorescence.

15. The synthesis method of the calixarene rare earth cluster according to any one of claims 1-14, wherein the synthesis method comprises placing a rare earth salt and a calixarene analog in a solvent, and preparing the calixarene rare earth cluster by a hydrothermal method or a solvothermal method; The molar ratio of the rare earth salt to the calixarene analog is (0.1-10):1; The solvent is selected from at least one of methanol, acetonitrile, DMF, DMA, DME, and H2O; The conditions of the solvothermal method include: After maintaining the temperature at 80-180 °C for 1-50 h, the temperature is decreased; The temperature decrease includes decreasing the temperature at a rate of 1-5 °C / h; The synthesis method further comprises washing after obtaining a solid by the solvothermal method.

16. A fluorescent material, which comprises the calixarene rare earth cluster according to any one of claims 1-14.

17. The application of the calixarene rare earth cluster according to any one of claims 1-14 and / or the fluorescent material according to claim 16 in the fields of lighting, display, clinical diagnosis, radiation detection or safety detection.

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