Red light-emitting material of beta-diketone Schiff base europium-zinc complex as well as preparation method and application of red light-emitting material

Abstract

The invention discloses a red light emitting material of a beta-diketone Schiff base europium-zinc complex and a preparation method of the red light emitting material, and belongs to the technical field of light emitting materials, the molecular formula of the beta-diketone Schiff base europium-zinc complex is C61H50ClEuN2O9Zn, the preparation method of the red light emitting material comprises the steps of synthesis of a Schiff base ligand, synthesis of a Schiff base zinc complex, synthesis of a europium zinc complex and synthesis of the beta-diketone Schiff base europium zinc complex. The maximum ultraviolet absorption wavelength and the maximum fluorescence emission wavelength in acetonitrile are 360 nm and 613 nm respectively, the compound can serve as a stable red light emitting material, and the preparation method is easy to operate, mild in reaction condition, high in product purity, good in red light emitting effect, suitable for large-scale production and convenient for practical application.

Description

Technical Field

[0001] The present invention relates to the technical field of luminescent materials, and particularly to a red-emitting luminescent material of β-diketone Schiff base europium zinc complex, a preparation method thereof, and an application thereof. Technical Background

[0002] Lanthanide metals have unique optical properties and long fluorescence lifetimes. However, due to the forbidden f-f transitions of lanthanide metal ions, the luminescence efficiency is low. In the prior art, red fluorescent phosphors doped with lanthanide metals and other substances are generally prepared.

[0003] In a Chinese invention patent with an application date of August 29, 2024 and an application number of 202411197366.2, a Eu 3+ -doped boron aluminate red-orange luminescent material, a preparation method thereof, and an application thereof are disclosed. This material can be effectively excited by light with near-ultraviolet and blue light wavelengths and emits a sharp spectrum with a wavelength peak located at 593 nanometers. The red-orange luminescence has pure chromaticity, high luminescence intensity, and good thermal stability. This Eu 3+ -doped boron aluminate red-orange luminescent material can be combined with near-ultraviolet or blue light semiconductor chips to prepare corresponding white LED lighting devices.

[0004] In a Chinese invention patent with an application date of September 3, 2024 and an application number of 202411228288.8, a europium-doped fluorapatite red fluorescent phosphor and a preparation method thereof are disclosed. A europium-doped apatite-based red fluorescent phosphor is disclosed. The general formula of the apatite-based phosphor is Ca 10 -xEux(PO 4 ) 6 F 2 , where: the matrix is Ca 10 (PO 4 )6F 2 , the activator is Eu 3+ , and it is obtained by replacing the cations in the matrix with Eu 3+ ; 0.02 ≤ x ≤ 0.2; the phosphor Ca 10 -xEux(PO 4 ) 6 X 2 is prepared by a hydrothermal synthesis method. This method can be used as a red fluorescent phosphor with relatively good thermal stability. The preparation process is simple, environmentally friendly, and convenient for large-scale production.

[0005] A patent for invention with an application date of October 15, 2024 and an application number of 202411434061.9 discloses a red-light emitting material, its preparation method and application. It discloses a red-light emitting material, its preparation method and application, belonging to the technical field of organic light-emitting materials. In the present invention, a phthalimide structure is introduced as an acceptor, and N,N,N',N'-tetraphenyl-9H-carbazole-2,7-diamine is used as a donor. By reducing ΔEST, promoting reverse intersystem crossing, and enhancing the electron-donating ability of the donor, a red-light TADF material with ΔEST < 0.05 eV is successfully prepared, which is beneficial to improving the efficiency of red-light OLED devices.

[0006] However, in the above-mentioned prior art, the mechanical properties, thermal stability, chemical resistance, and photosensitivity of the red-light emitting material produced need to be further improved, and the manufacturing method also needs to be further improved. Summary of the Invention

[0007] In order to solve the above technical problems, the present invention provides a red-light emitting material of β-diketone Schiff base europium zinc complex, which has good mechanical properties, thermal stability, chemical resistance, and high-sensitivity luminescent material. At the same time, the present invention provides a preparation method of a red-light emitting material of β-diketone Schiff base europium zinc complex, which is simple in operation, mild in reaction conditions, and high in product purity.

[0008] The red-light emitting material of β-diketone Schiff base europium zinc complex provided by the present invention, the structural formula of the β-diketone Schiff base europium zinc complex is:

[0009] The molecular formula of the β-diketone Schiff base europium zinc complex is: C 61 H 50 ClEuN 2 O 9 Zn, and the molecular weight is: 1207.84.

[0010] The present invention provides a preparation method of a red-light emitting material of β-diketone Schiff base europium zinc complex, and the preparation method includes the following steps: Step 1, synthesis of Schiff base ligand: (1S,2S)-1,2-diphenylethylenediamine and o-vanillin are prepared to obtain Schiff base ligand HL through a condensation reaction. 2 The structural formula of it is: Step 2, synthesis of Schiff base zinc complex: Schiff base ligand HL and anhydrous zinc acetate Zn(CH 2 COO) 3 are reacted to synthesize Schiff base zinc complex ZnL, and the structural formula of it is: 3 Step 3, Synthesis of europium-zinc complex: React the Schiff base zinc complex ZnL and EuCl 3 ·6H 2 O by reflux reaction to obtain the europium-zinc complex, and its structural formula is: Step 4, Synthesis of β-diketone Schiff base europium-zinc complex: Add dibenzoylmethane to the europium-zinc complex solution in Step 3, react at room temperature, let it stand and filter to obtain a yellow-green transparent solution β-ZnEuL. β-ZnEuL is (1S,2S)-1,2-diphenylethylenediamine-o-vanillin β-diketone europium-zinc complex, that is, β-diketone Schiff base europium-zinc complex, and its structural formula is:

[0011] As a further improvement measure of the present invention, for the preparation method of the above-mentioned red-light emitting material of β-diketone Schiff base europium-zinc complex, anhydrous methanol is added in Step 1, the molar ratio of (1S,2S)-1,2-diphenylethylenediamine to o-vanillin is 1:2, reflux for 6 hours by magnetic stirring, then cool, filter under reduced pressure, wash with methanol 2-3 times, and dry in an oven to obtain the Schiff base ligand H 2 L. The yellow powder of the Schiff base ligand H 2 L obtained in this way has a high yield.

[0012] As a further improvement measure of the present invention, for the preparation method of the above-mentioned red-light emitting material of β-diketone Schiff base europium-zinc complex, the molar ratio of the Schiff base ligand H 2 L and Zn(CH 3 COO) 3 in Step 2 is 1:1, the reaction temperature is set at 25 °C, the reflux reaction time is 10 hours, and then filter under reduced pressure.

[0013] As a further improvement measure of the present invention, for the preparation method of the above-mentioned red-light emitting material of β-diketone Schiff base europium-zinc complex, the molar ratio of the Schiff base zinc complex and EuCl 3 ·6H 2 O in Step 3 is 2:1, the reaction temperature is set at 25 °C, and the reflux reaction time is 10 hours.

[0014] As a further improvement measure of the present invention, for the preparation method of the above-mentioned red-light emitting material of β-diketone Schiff base europium-zinc complex, the molar ratio of the europium-zinc complex and dibenzoylmethane in Step 4 is 1:2.

[0015] As a further improvement measure of the present invention, for the preparation method of the above-mentioned red-light emitting material of β-diketone Schiff base europium zinc complex, the reaction time between dibenzoylmethane and the europium zinc complex solution described in step 4 is set to 9 to 11 hours.

[0016] As a further improvement measure of the present invention, for the preparation method of the above-mentioned red-light emitting material of β-diketone Schiff base europium zinc complex, the reaction time between dibenzoylmethane and the europium zinc complex solution described in step 4 is set to 10 hours, so that the reaction is more complete and the product yield is high.

[0017] As a further improvement measure of the present invention, for the preparation method of the above-mentioned red-light emitting material of β-diketone Schiff base europium zinc complex, the above-mentioned red-light emitting material of β-diketone Schiff base europium zinc complex is applied in an organic optoelectronic display.

[0018] Beneficial effects of the present invention: 1. The present invention provides a red-light emitting material of β-diketone Schiff base europium zinc complex, whose maximum ultraviolet absorption and fluorescence emission wavelengths in acetonitrile are 360 nm and 613 nm respectively. It has good red-light emitting effect, pure chromaticity of luminescence, high quantum yield of β-ZnEuL, and long fluorescence lifetime; 2. The present invention provides a red-light emitting material of Schiff base β-diketone Schiff base europium zinc complex, which can be used as a red-light material in the field of electroluminescence. This material can emit red light and can be used as a luminescent material in the field of optoelectronic materials; 3. The preparation method using the material of the present invention is simple in operation, mild in reaction conditions, and the product has high purity. Description of the Drawings

[0019] Figure 1 It is the solid fluorescence excitation and emission diagram of β-ZnEuL of the present invention.

[0020] Figure 2 It is the ultraviolet-visible absorption diagram of β-ZnEuL of the present invention.

[0021] Figure 3 It is the fluorescence lifetime decay diagram of β-ZnEuL of the present invention.

[0022] Figure 4 It is the infrared spectrum diagram of β-ZnEuL of the present invention. Detailed Embodiments

[0023] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below in conjunction with the drawings and specific embodiments.

[0024] A red-light emitting material of β-diketone Schiff base europium zinc complex, the structural formula is:

[0025] Molecular formula: C 61 H 50 ClEuN 2 O 9 Zn, molecular weight: 1207.84.

[0026] By doping europium rare earth complexes into LEDs, the luminous intensity in the red light part can be significantly enhanced, thus achieving efficient white LEDs.

[0027] Example 1, a preparation method of a red light emitting material of a β-diketone Schiff base europium zinc complex. Take (1S,2S)-1,2-diphenylethylenediamine (2.1200 g, 10 mmol) and o-vanillin (3.3500 g, 22 mmol), place them in a 50 ml round bottom flask, add 25 ml of anhydrous methanol, stir magnetically at a speed of 500 r / min, reflux for 10 hours, then cool in a refrigerator until a large amount of light yellow solid precipitates, and filter under reduced pressure. Wash with methanol 2 - 3 times, and dry in an oven to obtain the Schiff base ligand H 2 L. The Schiff base ligand H 2 L is a yellow powder, weighing 4.0810 g, with a yield of 84.99%. Its synthetic route is as follows:

[0028] Take the dried Schiff base ligand (1.0130 g, 2.1 mmol) and place it in a 25 ml round bottom flask, add 20 ml of methanol to dissolve, and then add anhydrous zinc acetate (0.4366 mg, 2.31 mmol). React under reflux at room temperature for 10 hours, and filter to obtain 0.6756 mg of the light green solid product Schiff base zinc complex ZnL, with a yield of 59.34%. Its synthetic route is as follows:

[0029] Take the dried Schiff base zinc complex (0.5418 g, 1 mmol) and place it in a 25 ml round bottom flask, add 10 ml of methanol to dissolve, and then add EuCl 3 ·6H 2 O (0.0401 g, 2.1 mmol). React under reflux at room temperature for 10 hours to obtain 0.324 g of europium zinc complex solution, with a reaction yield of 52.37%. Its synthetic route is as follows:

[0030] Dibenzoylmethane (0.442 g, 2 mmol) was added to the europium-zinc complex solution, and the reaction was refluxed for 10 hours at room temperature. After standing and filtering, the filtrate was sealed in a 15 mL long test tube and allowed to stand and volatilize. Orange-yellow crystals were precipitated after one week, and a yellow-green transparent solution β-ZnEuL of 0.0425 g was obtained, with a reaction yield of 35.21%. β-ZnEuL is a europium-zinc complex of (1S,2S)-1,2-diphenylethylenediamine-o-vanillin β-diketone, that is, a β-diketone Schiff base europium-zinc complex. A small amount of methanol was used to wash away the Schiff base zinc complex attached to the crystal surface, and after filtration, it was placed in a fume hood to air dry naturally. The synthesis route is as follows:

[0031] For the β-ZnEuL complex, when the excitation wavelength is 395 nm and the emission wavelengths are 589, 615, 666, and 687 nm respectively, the attributed transitions are 5 D 0 → 7 F 1 、 5 D 0 → 7 F 2 、 5 D 0 → 7 F 3 、 5 D 0→ 7 F 4 , with a quantum yield of 0.65% and a fluorescence lifetime of 4492 ns.

[0032] In the present invention, the strong light absorption ability of the organic aromatic ligand is utilized to transfer energy to the lanthanide metal atoms through the antenna effect, so that the lanthanide metal is transformed from the ground state to the excited state, and the excited state of the lanthanide metal radiates strong light at different energy level transitions. In the present invention, the Schiff base zinc complex is used as a sensitizer for the luminescence of the lanthanide metal in the fluorescent material. The lanthanide metal selects europium (Eu) element which can emit unique red light, so it is widely used in the luminescent material.

[0033] Europium rare earth complexes have excellent luminescent properties and chemical stability. In the field of LEDs, europium rare earth complexes are widely used to improve the luminescence efficiency and thermal stability of LED lights. In addition, europium rare earth complexes can be mixed with blue or green phosphors to form highly efficient white phosphors, which are widely used in near-ultraviolet light-excited LED lights. In the present invention, by reacting europium rare earth complexes with raw materials such as polymers, luminescent plastics with good mechanical properties, thermal stability, and chemical resistance can be prepared. This not only has excellent luminescent properties but also enhances its mechanical properties through hybrid processing. In the fields of temperature sensing and bioimaging, by utilizing the characteristic that the luminescence intensity of europium rare earth complexes changes with temperature, highly sensitive temperature sensors and low-toxicity fluorescent probes can be prepared for use in the field of bioimaging. In addition to the above main applications, europium rare earth complexes are also applied in the fields of information storage, display technology, optical communication amplifiers, etc.

[0034] Example 2, a preparation method of a red-light emitting material of a β-diketone Schiff base europium zinc complex. Take (1S,2S)-1,2-diphenylethylenediamine (1.2581 g, 6 mmol) and o-vanillin (1.9896, 12 mmol), place them in a 50 ml round-bottom flask, add 25 ml of anhydrous methanol, stir magnetically at a stirring speed of 500 r / min, reflux for 10 hours, then cool in a refrigerator until a large amount of light yellow solid precipitates, and filter under reduced pressure. Wash with methanol 2 - 3 times and dry in an oven to obtain the Schiff base ligand H 2 L, and the Schiff base ligand H 2 L is a yellow powder, weighing 1.0766 g, and the yield is 37.36%.

[0035] Take the dried Schiff base ligand (1.0404 g, 2.16 mmol) and place it in a 25 ml round-bottom flask, add 20 ml of methanol to dissolve it, and then add anhydrous zinc acetate (0.4549 g, 2.5 mmol). React under reflux at room temperature for 10 hours, and filter to obtain a light green solid product, the Schiff base zinc complex ZnL 0.647 g, and the yield is 55.25%.

[0036] Take the dried Schiff base zinc complex (0.0535 g, 1 mmol), place it in a 25 ml round-bottom flask, add 10 ml of methanol to dissolve it, and then add EuCl 3 ·6H 2 O (0.0412 g, 2.1 mmol). React under reflux at room temperature for 10 hours to obtain 0.435 g of europium zinc complex solution, and the reaction yield is 70.32%.

[0037] Dibenzoylmethane (0.450 g, 2 mmol) was added to the europium-zinc complex solution, and the mixture was refluxed at room temperature for 10 hours. After standing and filtration, the filtrate was sealed in a 15 mL long test tube and allowed to stand and volatilize. After one week, orange-yellow crystals precipitated, and a yellow-green transparent solution β-ZnEuL, 0.0469 g, with a reaction yield of 38.85% was obtained. After filtration, it was placed in a fume hood and air-dried naturally.

[0038] Example 3. A preparation method of a red-light emitting material of a β-diketone Schiff base europium-zinc complex. Take (1S,2S)-1,2-diphenylethylenediamine (2.0473 g, 10 mmol) and o-vanillin (3.36329 g, 22 mmol), place them in a 50 ml round-bottom flask, add 25 ml of anhydrous methanol, stir magnetically at a speed of 500 r / min, reflux for 10 hours, then cool in a refrigerator until a large amount of light yellow solid precipitates, and perform suction filtration. Wash with methanol 2 - 3 times and dry in an oven to obtain the Schiff base ligand H 2 L. The Schiff base ligand H 2 L is a yellow powder, weighing 3.265 g, with a yield of 68.00%.

[0039] Take the dried Schiff base ligand (0.9623 g, 2 mmol) and place it in a 25 ml round-bottom flask, add 20 ml of methanol to dissolve it, and then add anhydrous zinc acetate (0.3636, 2 mmol). Reflux at room temperature for 10 hours, and suction filter to obtain a light green solid product, Schiff base zinc complex ZnL 1.2542 g, with a yield of 68.07%.

[0040] Take the dried Schiff base zinc complex (0.551 g, 1 mmol), place it in a 25 ml round-bottom flask, add 10 ml of methanol to dissolve it, and then add EuCl 3 ·6H 2 O (0.400 g, 2.1 mmol). Reflux at room temperature for 10 hours to obtain 0.412 g of europium-zinc complex solution, with a reaction yield of 66.60%.

[0041] Dibenzoylmethane (0.445 g, 2 mmol) was added to the europium-zinc complex solution, and the mixture was refluxed at room temperature for 10 hours. After standing and filtration, the filtrate was sealed in a 15 mL long test tube and allowed to stand and volatilize. After one week, orange-yellow crystals precipitated, and a yellow-green transparent solution β-ZnEuL, 0.0525 g, with a reaction yield of 43.49% was obtained. After filtration, it was placed in a fume hood and air-dried naturally.

[0042] Example 4. As Figure 1 shown, weigh 10 mg of the luminescent material and dissolve it in acetonitrile to prepare 2.0×10 -4For the solution of [[ID=]], 3.0 ml of the above solution was pipetted into a cuvette and then measured on a TZS 980 steady-state fluorescence / phosphorescence chromatograph with the excitation slit and emission slit widths both being 3 nm and the excitation wavelength being 395 nm. It can be seen that the maximum fluorescence emission wavelength is 613 nm.

[0043] Example 5. The ultraviolet absorption spectrum was measured on a UV-2401PC Shimadzu ultraviolet spectrophotometer. The test was carried out at room temperature and external atmospheric pressure. The normalization result of the absorption test spectrum is shown in Figure 2 . It can be seen from the figure that the maximum ultraviolet absorption wavelength is 360 nm.

[0044] Example 6. The fluorescence lifetime data was measured on a TZS 980 steady-state fluorescence / phosphorescence chromatograph. See Figure 3 .

[0045] The fitting formula used is:

[0046] where R(t) is the fluorescence intensity at time t; B i refers to the pre-exponential factor of the i-th exponential component; τ i is the lifetime of the i-th exponential component; R(0) is the initial fluorescence intensity of the sample.

[0047] Substituting the parameters into the formula, the fluorescence lifetime was obtained: 4700 ns.

[0048] Example 7. A little luminescent material was weighed and mixed with KBr, ground and then pressed into a tablet, and tested with an infrared spectrometer (IS10).

[0049] As Figure 4 shown. IR(KBr, cm -1 ): 3651.12, 3380.73, 3057.99, 2361.10, 1627.49, 1605.69, 1595.00, 1550.53, 1516.90, 1476.89, 1453.23, 1439.15, 1388.94, 1298.85, 1238.37, 1220.16, 1168.98, 1101.14, 1074.78, 1024.21, 979.28, 941.31, 850.50, 813.47, 783.14, 742.07, 722.51, 701.28, 641.45, 618.27, 607.38, 546.25, 524.02, 455.05.

[0050] Example 8. The quantum yield was determined using the integrating sphere method on a TZS 980 steady-state fluorescence / phosphorescence chromatograph. The quantum yield of 0.65% was directly obtained. The specific formula is as follows:

[0051] where Φ F is the quantum yield of the sample; E b is the fluorescence integral (number of emitted photons) of the sample; A is the absorption value at the excitation wavelength; I S is the excitation peak area of the sample; I R is the excitation peak area of the blank sample, and the data is automatically calculated by the test instrument.

[0052] The embodiments of the present invention have been described in detail above in conjunction with the accompanying drawings. However, the specific embodiments described are only examples of the present invention. The present invention is not limited to the above embodiments. For those of ordinary skill in the art, several variations and improvements can be made without departing from the present invention, and these should also be regarded as belonging to the protection scope of the present invention.

Claims

1. A red light emitting material of a β-diketone Schiff base europium zinc complex, characterized in that: The structural formula of the β-diketone Schiff base europium zinc complex is:

2. The method for preparing the red light emitting material of a β-diketone Schiff base europium zinc complex according to claim 1, characterized in that: The preparation method comprises the following steps: Step 1, synthesis of Schiff base ligand: preparing Schiff base ligand H2L by condensation reaction of (1S, 2S)-1,2-diphenylethylenediamine and o-vanillin; Step 2, synthesis of Schiff base zinc complex: reacting Schiff base ligand H2L with anhydrous zinc acetate Zn(CH3COO)3 to synthesize Schiff base zinc complex ZnL; Step 3, synthesis of europium zinc complex: reflux Schiff base zinc complex ZnL and EuCl3·6H2O to obtain europium zinc complex; Step 4, synthesis of β-diketo Schiff base europium zinc complex: add dibenzoylmethane to the europium zinc complex solution in step 3, react at room temperature, let stand and filter to obtain a yellow-green transparent solution β-ZnEuL, i.e., β-diketo Schiff base europium zinc complex.

3. The method for preparing the red light emitting material of the β-diketone Schiff base europium zinc complex according to claim 2, characterized in that: In step 1, anhydrous methanol is added, and the molar ratio of the (1S, 2S)-1,2-diphenylethylenediamine to o-vanillin is 1:

2. The mixture is refluxed for 6 hours with magnetic stirring, cooled, and filtered under reduced pressure.

4. The method for preparing the red light emitting material of a β-diketone Schiff base europium zinc complex according to claim 2, characterized in that: The molar ratio of the Schiff base ligand H2L and Zn(CH3COO)3 described in step 2 is 1:1, the reaction temperature is set at 25°C, the reflux reaction time is 10 hours, and then the reduced pressure is filtered.

5. The method for preparing the red light emitting material of a β-diketone Schiff base europium zinc complex according to claim 2, characterized in that: The molar ratio of the Schiff base zinc complex and EuCl3·6H2O described in step 3 is 2:1, the reaction temperature is set at 25°C, and the reflux reaction time is 10 hours.

6. The method for preparing the red light emitting material of a β-diketone Schiff base europium zinc complex according to claim 2, characterized in that: The molar ratio of the europium zinc complex and dibenzoylmethane described in step 4 is 1:

2.

7. The method for preparing the red light emitting material of the β-diketone Schiff base europium zinc complex according to claim 6, characterized in that: The reaction time of the dibenzoylmethane and europium zinc complex solution in step 4 is set to 9 to 11 hours.

8. The method for preparing the red light emitting material of the β-diketone Schiff base europium zinc complex according to claim 7, characterized in that: The reaction time of the dibenzoylmethane and europium zinc complex solution in step 4 is set to 10 hours.

9. The use of a red light emitting material of a β-diketone Schiff base europium zinc complex according to claim 1, characterized in that: The red light emitting material of the beta-diketone Schiff base europium zinc complex is used in an organic photoelectric display.

Images