Rare earth organic complex, preparation method and application thereof

Abstract

The application discloses a rare earth organic complex and a preparation method and application thereof, and has the structure shown in formula (I). The anti-radiation performance of the rare earth organic complex is improved, the rare earth organic complex has good absorption in an ultraviolet light region and a blue light region less than 500 nm, can be excited by light in a wavelength range less than 460 nm, is converted into visible light greater than 500 nm, and can be used for preparing a light conversion film.

Description

TECHNICAL FIELD

[0001] The present application relates to a rare earth organic complex and a preparation method and application thereof, in particular to a rare earth organic complex for forming a light conversion film and a preparation method and application thereof. BACKGROUND

[0002] The rare earth complex is usually the first choice for manufacturing light conversion materials due to its unique 4f emission characteristic peak. In the case of photoluminescence, the coordination ligand absorbs energy from the excitation light source and transfers it to the core metal ion. The ligand plays a very important role in improving the utilization rate of light energy.

[0003] The light conversion film is a film prepared by adding a light conversion functional master batch to the raw material for producing a common film. The conversion agent contained in the light conversion film can convert the high-energy short wave in sunlight into low-energy long wave and medium-long wave, or can improve the shed temperature to provide suitable light conditions for crops, promote crop growth and increase yield.

[0004] CN1408810A discloses a biomimetic fluorescent powder conversion agent for agricultural film, which comprises a diketone ligand, an aromatic carboxylic acid ligand and a phosphorus-containing oxy compound. The obtained fluorescent powder conversion agent can absorb short-wave ultraviolet light of 240-400 nm and emit high-intensity cyan-blue light of 400-500 nm. CN101358128A discloses a rare earth organic complex conversion agent and a preparation method thereof, which uses a diketone as a ligand and o-phenanthroline, bipyridine, tri-n-octyl phosphine oxide and triphenyl phosphine oxide as a synergistic ligand. CN101857690A discloses a rare earth organic complex light conversion film, which is prepared from a base, a light conversion agent and an additive. The light conversion agent is prepared from raw materials including rare earth oxides, diketones and phenanthroline. CN108192598A discloses a preparation method of a composite rare earth light conversion agent for agricultural film, which generates amino and carboxyl functionalized carbon dots through silk hydrothermal reaction, and chelates rare earth ions by using the surface multi-amino and carboxyl structures to form multi-element light emission centers. At the same time, methyl benzotriazole is used as the first ligand, o-phenanthroline is used as the synergistic ligand, and a surfactant is added. The obtained light conversion agent can convert the ultraviolet part of sunlight into red and blue light which is more suitable for photosynthesis of crops.

[0005] However, the poor ultraviolet radiation resistance of the complex limits its practical application. This is a fatal defect of luminescent materials and should be solved. In order to solve this defect, it is still an important way to develop new rare earth complex luminescent materials by trying to develop new ligands to obtain new rare earth organic complexes. SUMMARY

[0006] Therefore, one object of the present application is to provide a rare earth organic complex with improved radiation resistance. Further, it has good absorption in the ultraviolet region and the blue region less than 500 nm, and can be excited by light in the wavelength range less than 460 nm to convert it into visible light greater than 500 nm. It can be applied to form a light conversion film. Another object of the present application is to provide a preparation method of the above-mentioned rare earth organic complex. Still another object of the present application is to provide an application of the above-mentioned rare earth organic complex. The above technical objects are achieved by the technical solutions disclosed herein.

[0007] In one aspect, the present application provides a rare earth organic complex having a structure shown in formula (I):

[0008]

[0009] In formula (I), Ln represents a trivalent rare earth metal ion;

[0010] R1, R2, R3, R4, R5, R6, R7 are each independently selected from hydrogen, C1-C6 alkyl or C1-C6 alkoxy; R8, R9, R 10 are each independently selected from hydrogen, C1-C4 alkyl; R 11 is independently selected from hydrogen, C1-C3 alkyl.

[0011] According to the rare earth organic complex of the present application, preferably, R1, R2, R3, R4, R5, R6, R7 are each independently selected from hydrogen, C1-C3 alkyl or C1-C3 alkoxy; R8, R9, R 10 are each independently selected from hydrogen, C1-C3 alkyl; R 11 is independently selected from hydrogen, methyl or ethyl.

[0012] According to the rare earth organic complex of the present application, preferably, R1, R2, R3, R4, R5, R6, R7 are each independently selected from hydrogen, C1-C3 alkyl; R8, R9, R 10 are each independently selected from hydrogen, methyl or ethyl; R 11 is independently selected from hydrogen.

[0013] According to the rare earth organic complex of the present application, preferably, R1, R2, R3, R4, R5, R6, R7, R8, R9, R 10 are each independently selected from hydrogen or methyl.

[0014] According to the rare earth organic complex of the present application, preferably, Ln is selected from one or more of Eu 3+ , Sm 3+ , Tb 3+ , Dy 3+ .

[0015] According to the rare earth organic complex of the present application, preferably, it has a structure as shown in formula (II):

[0016]

[0017] In another aspect, the present application also provides a preparation method of the rare earth organic complex as described above, comprising the following steps:

[0018] (1) mixing a water-soluble rare earth salt, a compound as shown in formula (A), a compound as shown in formula (B) and an alcohol solvent under stirring at 45-70℃ to obtain an alcohol solution;

[0019] (2) adding a solution of alkali metal hydroxide into the alcohol solution to react, cooling, standing, solid-liquid separation to obtain a rare earth organic complex having a structure as shown in formula (I);

[0020]

[0021] In formula (A), R1, R2, R3, R4, R5, R6, R7 are each independently selected from hydrogen, C1-C6 alkyl or C1-C6 alkoxy;

[0022] In formula (B), R8, R9, R 10 are each independently selected from hydrogen, C1-C4 alkyl; R 11 is independently selected from hydrogen, C1-C3 alkyl;

[0023] wherein the rare earth metal ion in the water-soluble rare earth salt is denoted as Ln, and Ln is a trivalent rare earth metal ion;

[0024] wherein the molar ratio of the compound as shown in formula (A) to the trivalent rare earth metal ion in the water-soluble rare earth salt is 1-1.05:1; and the molar ratio of the compound as shown in formula (B) to the trivalent rare earth metal ion in the water-soluble rare earth salt is 3-3.05:1;

[0025] wherein the alcohol solvent is selected from one or more of methanol, ethanol, isopropanol or n-butanol.

[0026] According to the preparation method of the present application, preferably, the alkali metal hydroxide is selected from sodium hydroxide and / or potassium hydroxide.

[0027] According to the preparation method of the present application, preferably, the compound as shown in formula (A) is obtained by reacting a compound as shown in formula (C) and a compound as shown in formula (D);

[0028]

[0029] R1, R2, R3, R4, R5, R6, R7 are independently selected from hydrogen, C1-C6 alkyl or C1-C6 alkoxy.

[0030] In still another aspect, the application further provides a use of the rare earth organic complex as described above in the preparation of a light conversion film, comprising any one of the following steps:

[0031] (I) mixing the rare earth organic complex with a master batch for forming a polymer film, and pressing to obtain a light conversion film;

[0032] (II) coating the rare earth organic complex on the surface of a polymer film to form a light conversion film.

[0033] The anti-radiation performance of the rare earth organic complex is improved, and the service life of the complex is prolonged. The rare earth organic complex has good absorption in the ultraviolet region and the blue light region less than 500 nm, and can be excited by light in the wavelength range less than 460 nm to convert it into visible light greater than 500 nm. The rare earth organic complex can be used in a light conversion film, and can effectively convert ultraviolet and blue light into visible light greater than 500 nm. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 is the X-ray diffraction single crystal structure of the rare earth organic complex Eu(TTA)3BIP obtained in Example 1 of the application.

[0035] Figure 2 is the fluorescence excitation spectrum of the rare earth organic complex Eu(TTA)3BIP obtained in Example 1 of the application.

[0036] Figure 3 is the fluorescence emission spectrum of the rare earth organic complex Eu(TTA)3BIP obtained in Example 1 of the application.

[0037] Figure 4 is the anti-radiation performance comparison chart of the rare earth organic complex Eu(TTA)3BIP obtained in Example 1 of the application.

[0038] Figure 5 is the transmittance chart of the light conversion film prepared in Application Example 1 of the application.

[0039] Figure 6 is the light conversion effect comparison chart of the light conversion film in Application Example 1 of the application and a simple polyethylene film. DETAILED DESCRIPTION

[0040] The application will be further described below in conjunction with specific examples, but the protection scope of the application is not limited thereto.

[0041] <EXPLANATION OF TERMS>

[0042] In the present application, Cm-Cn means having m ~ n carbon atoms; for example, C1-C6 alkyl means alkyl having 1 ~ 6 carbon atoms.

[0043] In the present application, "alkyl" means a group having one point of attachment, derived from a straight-chain or branched aliphatic hydrocarbon.

[0044] <Rare earth organic complex>

[0045] The rare earth organic complex of the present application has a structure represented by Formula (I):

[0046]

[0047] Such a rare earth organic complex can be used as a light conversion agent for forming a light conversion film, effectively converting blue light and ultraviolet light with a wavelength of 500 nm or less into visible light of other wavelengths, and its radiation resistance is improved.

[0048] In Formula (I), Ln represents a trivalent rare earth metal ion. Preferably, Ln is selected from one or more of Eu 3+ , Sm 3+ , Tb 3+ , Dy 3+ . More preferably, Ln is selected from one of Sm 3+ , Eu 3+ , Tb 3+ , Dy 3+ .

[0049] R1may be selected from hydrogen, C1-C6 alkyl or C1-C6 alkoxy, preferably from hydrogen or C1-C6 alkyl, more preferably from hydrogen or C1-C3 alkyl, further preferably from hydrogen, methyl or ethyl.

[0050] R2may be selected from hydrogen, C1-C6 alkyl or C1-C6 alkoxy, preferably from hydrogen or C1-C6 alkyl, more preferably from hydrogen or C1-C3 alkyl, further preferably from hydrogen, methyl or ethyl.

[0051] R3may be selected from hydrogen, C1-C6 alkyl or C1-C6 alkoxy, preferably from hydrogen or C1-C6 alkyl, more preferably from hydrogen or C1-C3 alkyl, further preferably from hydrogen, methyl or ethyl.

[0052] R4may be selected from hydrogen, C1-C6 alkyl or C1-C6 alkoxy, preferably from hydrogen or C1-C6 alkyl, more preferably from hydrogen or C1-C3 alkyl, further preferably from hydrogen, methyl or ethyl.

[0053] R5may be selected from hydrogen, C1-C6alkyl or C1-C6alkoxy, preferably from hydrogen or C1-C6alkyl, more preferably from hydrogen or C1-C3alkyl, further preferably from hydrogen, methyl or ethyl.

[0054] R6may be selected from hydrogen, C1-C6alkyl or C1-C6alkoxy, preferably from hydrogen or C1-C6alkyl, more preferably from hydrogen or C1-C3alkyl, further preferably from hydrogen, methyl or ethyl.

[0055] R7may be selected from hydrogen, C1-C6alkyl or C1-C6alkoxy, preferably from hydrogen or C1-C6alkyl, more preferably from hydrogen or C1-C3alkyl, further preferably from hydrogen, methyl or ethyl.

[0056] In the present application, examples of C1-C6alkyl include, but are not limited to, methyl, ethyl, n-propyl, i-propyl, n-butyl, t-butyl, pentyl, hexyl. Examples of C1-C6alkoxy include, but are not limited to, methoxy, ethoxy, propoxy, butoxy, pentoxy, hexyloxy.

[0057] According to a specific embodiment of the present application, R1, R2, R3, R4, R5, R6, R7are all hydrogen.

[0058] R8may be selected from hydrogen, C1-C4alkyl, preferably from hydrogen, C1-C3alkyl, more preferably from hydrogen, methyl or ethyl. In the present application, examples of C1-C4alkyl include, but are not limited to, methyl, ethyl, n-propyl, butyl.

[0059] R9may be selected from hydrogen, C1-C4alkyl, preferably from hydrogen, C1-C3alkyl, more preferably from hydrogen, methyl or ethyl.

[0060] R 10 may be selected from hydrogen, C1-C4alkyl, preferably from hydrogen, C1-C3alkyl, more preferably from hydrogen, methyl or ethyl.

[0061] According to a specific embodiment of the present application, R8, R9, R 10 are all hydrogen.

[0062] R 11 are independently selected from hydrogen, C1-C3alkyl, preferably from hydrogen, methyl or ethyl, more preferably from hydrogen or methyl. According to a specific embodiment of the present application, R 11 is hydrogen.

[0063] According to an embodiment of the present application, the rare earth organic complex has a structure represented by formula (II):

[0064]

[0065] In formula (II), Ln represents a trivalent rare earth metal ion.

[0066] <Method for producing rare earth organic complex>

[0067] The method for producing the rare earth organic complex of the present application includes the following steps: a raw material mixing and dissolving step; a rare earth organic complex forming step. Optionally, it also includes a 2-(pyrimidin-2-yl)-1H-benzo[d]imidazole ligand forming step. The details are described below.

[0068] 2-(pyrimidin-2-yl)-1H-benzo[d]imidazole ligand formation step

[0069] The compound represented by formula (C) is reacted with the compound represented by formula (D) to obtain the compound represented by formula (A), i.e. the 2-(pyrimidin-2-yl)-1H-benzo[d]imidazole ligand.

[0070]

[0071]

[0072] The substituents R1 to R7 in formula (C) and formula (D) are as described above, and are not described here again.

[0073] The molar ratio of the compound represented by formula (C) to the compound represented by formula (D) is 1:1.05 to 1.25, preferably 1:1.1 to 1.25, and more preferably 1:1.15 to 1.2.

[0074] The reaction temperature can be 155 to 170°C, preferably 160 to 170°C, and more preferably 160 to 165°C. The reaction time can be 1.5 to 4h, preferably 2 to 4h, and more preferably 2 to 3h.

[0075] In the present application, 2-cyanopyrimidine and o-phenylenediamine can be directly mixed under an inert gas atmosphere, and a solvent can not be added. The inert gas can be argon or nitrogen. After mixing the two, the reaction is directly heated. After the reaction is completed, the reaction product is dissolved in ethanol, filtered, the insoluble matter is filtered out, the solvent is evaporated under reduced pressure, and the compound represented by formula (A) is obtained.

[0076] In formula (I), the 2-(pyrimidin-2-yl)-1H-benzo[d]imidazole ligand is the main ligand, and the β-diketone ligand is the second ligand.

[0077] raw material mixed solution formation step

[0078] The water-soluble rare earth salt, the compound represented by formula (A), and the compound represented by formula (B) are mixed with an alcohol solvent to obtain an alcohol solution.

[0079] In some embodiments, the compound shown as formula (A) and the compound shown as formula (B) are mixed with an alcohol solvent, and then a water-soluble rare earth salt is added to the mixture to obtain an alcohol solution.

[0080]

[0081] R8 to R 11 The definition of the substituent groups is as described above and will not be repeated here.

[0082] The rare earth ion in the water-soluble rare earth salt is denoted as Ln, and Ln is a trivalent rare earth metal ion, and Ln is selected from one or more of Eu 3+ , Sm 3+ , Tb 3 + , Dy 3+ . More preferably, Ln is selected from one of Eu 3+ , Sm 3+ , Tb 3+ , Dy 3+ . Ln, in each occurrence, independently represents Sm 3+ , Eu 3+ , Tb 3+ , or Dy 3+ . The water-soluble rare earth salt can be a rare earth nitrate, a rare earth chloride, or a rare earth sulfate, and is preferably a rare earth chloride. The water-soluble rare earth salt can be a rare earth salt with or without crystal water.

[0083] The molar ratio of the compound shown as formula (A) to the trivalent rare earth metal ion in the water-soluble rare earth salt is 1-1.05:1, preferably 1-1.03:1, and more preferably 1.01-1.02:1. The molar ratio of the compound shown as formula (B) to the trivalent rare earth metal ion in the water-soluble rare earth salt is 3-3.05:1, preferably 3-3.03:1, and more preferably 3.01-3.02:1.

[0084] The alcohol solvent is selected from one or more of methanol, ethanol, isopropanol, or n-butanol, and is preferably selected from one of methanol, ethanol, isopropanol, or n-butanol, and is more preferably methanol or ethanol.

[0085] The mixing can be heated, and the heating temperature can be 45-70°C, preferably 55-70°C, and more preferably 60-65°C.

[0086] rare earth organic complex formation step

[0087] The alkali metal hydroxide solution is added to the alcohol solution to react, cooled, and then allowed to stand, and then solid-liquid separation is performed to obtain a rare earth organic complex having a structure shown as formula (I).

[0088] The alkali metal hydroxide is selected from sodium hydroxide and / or potassium hydroxide, and preferably is sodium hydroxide. The concentration of the alkali metal hydroxide solution can be 0.5-5 mol / L, preferably 1-4 mol / L, and more preferably 1-3 mol / L.

[0089] In some embodiments, the alkali metal hydroxide solution is added dropwise to the alcohol solution at 55-70°C, and reacted until no precipitate is produced, then reduced to room temperature, and left to stand for 5-12 h, and then solid-liquid separation is performed to obtain crystals, which are the rare earth organic complex having the structure shown in formula (I).

[0090] In formula (I), the coordination number of Ln is 8, the 2-(pyrimidin-2-yl)-1H-benzo[d]imidazole ligand provides 2 coordination sites, and each of the three β-diketone ligands provides 2 coordination sites. The present application finds that the 2-(pyrimidin-2-yl)-1H-benzo[d]imidazole as a neutral ligand has significant advantages, and can enhance the ultraviolet resistance of the rare earth organic complex.

[0091] <Applications>

[0092] The present application also provides a use of the rare earth organic complex as described above in the preparation of a light conversion film. Specifically, the use of the rare earth organic complex as a light conversion agent in the preparation of a light conversion film.

[0093] In use, the rare earth organic complex can be coated on the surface of a polymer film to form a light conversion film. The coating method can use those known in the art. Alternatively, the rare earth organic complex can be mixed with a master batch for forming a polymer film, and then pressed to obtain a light conversion film. The pressing method can use those known in the art, and will not be described here.

[0094] The polymer film can be one of polyethylene terephthalate (PET), polyethylene (PE), polyvinyl chloride (PVC), polytetrafluoroethylene (PTFE), or ethylene-tetrafluoroethylene copolymer (ETFE), and preferably is polyethylene.

[0095] The mass ratio of the rare earth organic complex to the master batch for forming a polymer film can be 0.01-0.15:10, and preferably is 0.05-0.1:10.

[0096] In the present application, the formed light conversion film has a lower transmittance for blue light less than 500 nm, can effectively absorb blue light and ultraviolet light, and convert them into red light.

[0097] <Testing Methods>

[0098] The fluorescence excitation and emission spectra are tested by a Horiba FL-3 fluorescence spectrometer. 1H NMR spectra were tested on a Bruker Avance III HD 500MHz nuclear magnetic resonance spectrometer. Single crystal data were collected using a Bruker SMART APEX II X-ray diffractometer.

[0099] <Source of raw materials>

[0100] In the following examples, EuCl3·6H2O (99.9%), SmCl3·6H2O (99.9%), TbCl3·6H2O (99.9%), DyCl3·6H2O (99.9%) were purchased from Shanghai Aldrin Reagent Co., Ltd. 2-cyanopyrimidine (98%), o-phenylenediamine (98%) and 2-thiophenecarboxaldehyde trifluoroacetone (TTA, 98%) were purchased from Macklin Biochemical Technology Co., Ltd.

[0101] Example 1

[0102] Reaction equation:

[0103]

[0104] Under N2atmosphere, 1.05 g (0.010 mol) of 2-cyanopyrimidine and 1.30 g (0.012 mol) of o-phenylenediamine were mixed and heated to 160°C under stirring. As the temperature rose, the solid melted into a liquid. As the reaction was completed, a new compound was generated and the reaction system was converted into a solid. This process took about 2 h. The product was dissolved in ethanol and the insoluble matter was filtered out. The solvent was evaporated under reduced pressure to obtain 2-(pyrimidin-2-yl)-1H-benzo[d]imidazole.

[0105] The structural characterization of 2-(pyrimidin-2-yl)-1H-benzo[d]imidazole is as follows: 1 H NMR (CDCl3, 500 Hz), δ 10.45 (1H), 8.90 (2H), 7.60 (1H), 7.36 (2H), 6.75 (2H).

[0106] EuCl3·6H2O (99.9%) (0.37 g, 1 mmol) was added to a 50 mL ethanol solution of 2-thiophenecarboxaldehyde trifluoroacetone (0.67 g, 3 mmol) and 2-(pyrimidin-2-yl)-1H-benzo[d]imidazole (0.20 g, 1 mmol) at 60°C to obtain an alcoholic solution. To the alcoholic solution, 1M NaOH solution was added dropwise to control the reaction liquid to be free of precipitate. The solution was cooled and left overnight, and was filtered to obtain a rare earth europium organic complex, denoted as Eu(TTA)3BIP.

[0107] The rare earth europium organic complex Eu(TTA)3BIP of the present example was characterized.

[0108] The single crystal structure test results are shown below. Figure 1 The results of fluorescence excitation and emission spectroscopy measurements are shown in the figures below. Figure 2 and Figure 3 . Figure 4 The results show the comparison of the radiation resistance properties of rare earth europium organic complex Eu(TTA)3BIP and β-diketone ligand Eu complex Eu(TTA)3.

[0109] As shown in the figure, the rare-earth europium organic complex Eu(TTA)3BIP exhibits good absorption in the ultraviolet region and the blue light region below 500 nm, and can be excited by light in the wavelength range below 500 nm, with the optimal excitation wavelength being 394 nm. The fluorescence emission spectrum mainly shows peaks at 594, 612, 653, and 701 nm, which are attributed to trivalent Eu. 3+ Ionic 5 D0→ 7 F1 5 D0→ 7 F2 5 D0→ 7 F3 and 5 D0→ 7 The F4 characteristic emission is a bright red light. After irradiation for 180 minutes, the fluorescence emission intensity of the rare earth europium organic complex Eu(TTA)3BIP decreased by only about 10%, while the fluorescence emission intensity of the complex Eu(TTA)3 decreased by nearly 80%, indicating that the radiation resistance of the rare earth europium organic complex Eu(TTA)3BIP of this invention is significantly improved. This invention infers that the introduction of the 2-(pyrimidin-2-yl)-1H-benzo[d]imidazolium ligand can improve the radiation resistance of the complex.

[0110] Examples 2 to 4

[0111] The only difference from Example 1 is that the water-soluble rare earth salts used in Examples 2 to 4 are TbCl3·6H2O (99.9%), SmCl3·6H2O (99.9%), and DyCl3·6H2O (99.9%), respectively, which yielded rare earth organic complexes with structures as shown in formulas (102), (103), and (104), respectively.

[0112]

[0113] Application Example 1

[0114] The rare earth organic complex Eu(TTA)3BIP prepared in Example 1 was ground in an agate mortar to obtain a fine and uniform powder. Then, 0.1 g of the Eu(TTA)3BIP complex and 10 g of linear low-density polyethylene masterbatch were weighed and set aside. The 0.1 g Eu(TTA)3BIP complex and 10 g of linear low-density polyethylene masterbatch were mixed evenly at 120°C on a two-roll mill to obtain a mixed masterbatch. The mixed masterbatch was then pressed into a film using a flat vulcanizing apparatus at 120°C, resulting in a light-converting film.

[0115] The pressed light-converting film was subjected to transmittance testing, and the results are as follows: Figure 5 As shown, Figure 5 In this context, polyethylene film refers to a simple film without the addition of rare earth organic complexes; Eu(TTA)3BIP polyethylene film refers to the light-converting film prepared using Example 1. Figure 5 It can be seen that, compared with pure polyethylene film, the light-converting film with rare earth organic complex Eu(TTA)3BIP has a lower transmittance of blue light below 500nm, and can effectively absorb ultraviolet light and blue light and convert them into red light. Figure 6 This is a physical image of the light-converting thin film obtained in Example 1.

[0116] This invention is not limited to the above-described embodiments. Any modifications, improvements, or substitutions that can be conceived by those skilled in the art without departing from the essential content of this invention fall within the scope of this invention.

Claims

1. A rare earth organic complex, characterized by, It has the structure shown in formula (I): In formula (I), Ln represents a trivalent rare earth metal ion; R1, R2, R3, R4, R5, R6, R7, R8, R9, R 10 , R 11 are each hydrogen; Ln is selected from one or more of Eu 3+ , Sm 3+ , Tb 3+ , Dy 3+ .

2. The method for preparing rare earth organic complexes according to claim 1, characterized in that, The method comprises the following steps: (1) mixing a water-soluble rare earth salt, a compound shown in formula (A), a compound shown in formula (B) and an alcohol solvent at 45-70°C under stirring to obtain an alcohol solution; (2) adding a solution of alkali metal hydroxide to the alcohol solution for reaction, cooling, standing, solid-liquid separation, and obtaining a rare earth organic complex having the structure shown in formula (I); In formula (A), R1, R2, R3, R4, R5, R6 and R7 are all hydrogen. In formula (B), R8, R9, R 10 , and R 11 are each hydrogen. wherein the rare earth metal ion in the water-soluble rare earth salt is denoted as Ln, Ln is a trivalent rare earth metal ion; Ln is selected from Eu 3 + , Sm 3+ , Tb 3+ , Dy 3+ one or more. The molar ratio of the compound shown in formula (A) to the trivalent rare earth metal ion in the water-soluble rare earth salt is 1-1.05:1, and the molar ratio of the compound shown in formula (B) to the trivalent rare earth metal ion in the water-soluble rare earth salt is 3-3.05:

1. The alcohol solvent is selected from one or more of methanol, ethanol, isopropanol or n-butanol.

3. The preparation method according to claim 2, characterized in that, The alkali metal hydroxide is selected from sodium hydroxide and / or potassium hydroxide.

4. The production method according to claim 2, characterized by, The compound shown in formula (A) is obtained by reacting a compound shown in formula (C) and a compound shown in formula (D); In formula (A), R1, R2, R3, R4, R5, R6 and R7 are all hydrogen.

5. Use of the rare earth organic complex according to claim 1 in the preparation of light conversion film, characterized in that, The method comprises the following steps: (1) mixing a water-soluble rare earth salt, a compound shown in formula (A), a compound shown in formula (B) and an alcohol solvent at 45-70°C under stirring to obtain an alcohol solution; (2) adding a solution of alkali metal hydroxide to the alcohol solution for reaction, cooling, standing, solid-liquid separation, and obtaining a rare earth organic complex having the structure shown in formula (I); (1) mixing a water-soluble rare earth salt, a compound shown in formula (A), a compound shown in formula (B) and an alcohol solvent at 45-70°C under stirring to obtain an alcohol solution; (2) adding a solution of alkali metal hydroxide to the alcohol solution for reaction, cooling, standing, solid-liquid separation, and obtaining a rare earth organic complex having the structure shown in formula (I);

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