Rare earth complex fluorescent material as well as ultrasonic synthesis method and application thereof
The rare earth complex fluorescent material [Tb(2-Cl-6-FBA)3(4-OH-terpy)(EtO)]·0.75EtOH synthesized by ultrasonic synthesis solves the time spent on synthesis of rare earth complexes in the prior art. and the problem of harsh reaction conditions, the material has achieved good thermal stability and fluorescence performance, and is suitable for large-scale industrial applications.
Patent Information
- Application Number
- CN202411411649.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-11
- Publication Date
- 2025-01-10
AI Technical Summary
The existing rare earth complex fluorescent materials have problems such as thermal stability and fluorescent performance, and the synthesis method takes a long time or requires harsh high-temperature and high-pressure reaction conditions.
Ultrasonic synthesis method is used to synthesize the fluorescent materials of rare earth complexes. The chemical formula is [Tb(2-Cl-6-FBA)3(4-OH-terpy)(EtO)]·0.75EtOH. The rare earth inorganic salt solution is used under ultrasonic conditions. Add it dropwise to the ligand solution to obtain rare earth complex precipitation, and obtain fluorescent materials by suction filtration, washing and drying, which is suitable for large-scale production.
It achieves good thermal stability and excellent fluorescence performance of rare earth complexes, with a long fluorescence life, suitable for applications in the fields of lighting, luminescent probes and sensors, and the synthesis process is gentle, safe and efficient, short time-consuming and high yield.
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Figure CN119285656A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to fluorescent material technology, in particular to a rare earth complex fluorescent material, an ultrasonic synthesis method and application thereof. Background Art
[0002] Rare earth complex fluorescent materials have high-performance luminescent centers, which can show high color purity and long fluorescence lifetime in the excited state, so they can be used as ideal materials for lighting, luminescent probes and sensors. Rare earth ions have unique electronic structures and properties, but the forbidden transitions of 4f electrons limit the luminescence of rare earth ions. However, if rare earth ions are coordinated with strongly absorbing ligands, the formed rare earth complexes will transfer energy from the excited state of the ligand to the central metal through non-radiative transitions, thereby sensitizing the luminescence of rare earth ions. This phenomenon is called the "antenna" effect, which is manifested as a significant increase in luminescence intensity. Therefore, the synthesis and characterization of rare earth complexes have always received widespread attention.
[0003] However, existing rare earth complex fluorescent materials generally have the problem of not having both thermal stability and fluorescent properties. In addition, most existing methods for synthesizing rare earth complex fluorescent materials are time-consuming or require harsh reaction conditions such as high temperature and high pressure. Summary of the invention
[0004] The purpose of the present invention is to provide a rare earth complex fluorescent material, which has good thermal stability and excellent fluorescence performance, long fluorescence lifetime, and has good application prospects and large-scale industrial promotion potential in the fields of lighting, luminescent probes and sensors. The rare earth complex fluorescent material of the present invention can be synthesized by ultrasonic synthesis method, which has milder and simpler reaction conditions, faster reaction and is suitable for amplifying production.
[0005] It should be noted that, in the present invention, unless otherwise specified, the specific meaning of "including" in relation to composition limitations and descriptions includes both open-ended "including", "comprising", etc. and similar meanings, as well as closed-ended "composed of", "composed of", etc. and similar meanings.
[0006] To achieve the above object, the technical solution adopted by the present invention is: a rare earth complex fluorescent material, whose chemical formula is: [Tb(2-Cl-6-FBA)3(4-OH-terpy)(EtO)]·0.75EtOH, wherein Tb is a rare earth element, 2-Cl-6-FBA is deprotonated 2-chloro-6-fluorobenzoic acid, 4-OH-terpy is 4-hydroxy-2,2':6',2"-terpyridine, EtO is deprotonated ethanol, and the coordination number of the rare earth element corresponding to the rare earth complex fluorescent material is 9.
[0007] Furthermore, the rare earth complex fluorescent material has a fluorescence lifetime of 1.0-1.318 ms and can be widely used in related fields as a fluorescent material.
[0008] Another object of the present invention is to disclose an ultrasonic synthesis method of a rare earth complex fluorescent material, comprising the following steps:
[0009] Step (1), preparation of ligand solution: dissolving ligand 1 and ligand 2 in ethanol to prepare a ligand solution; then adjusting the pH of the ligand solution to 5.0-6.8; the ligand 1 is one of the halogenated benzoic acids, and the ligand 2 is one of the terpyridines;
[0010] Step (2), preparing a rare earth inorganic salt solution: dissolving a rare earth inorganic salt in deionized water to prepare a rare earth inorganic salt solution;
[0011] Step (3), ultrasonic synthesis: under ultrasonic conditions, the rare earth inorganic salt solution is added dropwise to the ligand solution to obtain a rare earth complex precipitate;
[0012] Step (4), filtering the rare earth complex precipitate, washing with ethanol, and drying to obtain rare earth complex fluorescent material powder;
[0013] Step (5), after filtering the rare earth complex precipitate, the obtained clear solution is allowed to stand to precipitate crystals, and the crystals are filtered and washed to obtain rare earth complex fluorescent material crystals.
[0014] Furthermore, the halogenated benzoic acid in step (1) is 2-chloro-6-fluorobenzoic acid.
[0015] Furthermore, the terpyridine is 4-hydroxy-2,2':6',2"-terpyridine.
[0016] Furthermore, in step (1), the molar ratio of ligand 1 to ligand 2 is 1:1-1:3.
[0017] Furthermore, the total concentration of the ligand in the ligand solution in step (1) is 0.1-0.3 mol / L.
[0018] Furthermore, the ethanol concentration in steps (1) and (4) is 95%.
[0019] Furthermore, in step (1), the pH of the ligand solution is adjusted to between 5.0 and 6.8 using a 0.5-3 mol / L NaOH solution.
[0020] Furthermore, the rare earth inorganic salt concentration in the rare earth inorganic salt solution in step (2) is 0.05-0.1 mol / L, preferably 0.06 mol / L.
[0021] Furthermore, the rare earth inorganic salt in step (2) is a nitrate of a rare earth.
[0022] Furthermore, the rare earth inorganic salt in step (2) is preferably terbium nitrate.
[0023] Furthermore, in step (3), the rare earth inorganic salt solution is added dropwise to the ligand solution at a molar ratio of the rare earth inorganic salt to the ligand of 1:1-1:3.
[0024] Furthermore, in step (3), the ultrasonic power is 50-100 W, and the ultrasonic time is 20-120 min. The ultrasonic power is preferably 50 W, and the ultrasonic time is preferably 80 min.
[0025] Furthermore, the drying in step (4) is carried out by drying with an infrared lamp.
[0026] Furthermore, in step (5), the mixture is allowed to stand at room temperature for 1-2 days to precipitate crystals.
[0027] Furthermore, the drying in step (5) is carried out by natural drying.
[0028] Another object of the present invention is to disclose the use of a rare earth complex fluorescent material in the fields of lighting, luminescent probes and sensors.
[0029] The rare earth complex fluorescent material, ultrasonic synthesis method and use thereof of the present invention have the following advantages compared with the prior art:
[0030] 1) The synthesis method of the rare earth complex fluorescent material of the present invention does not need to be carried out under high temperature and high pressure hydrothermal or solvent thermal conditions, and the synthesis process conditions are mild, safe and efficient.
[0031] 2) The ligand and rare earth metal salt used in the synthesis method of the rare earth complex fluorescent material of the present invention are easy to obtain, the synthesis reaction takes a short time, the yield is high, and it can be scaled up for production.
[0032] 3) The halogenated benzoic acid ligands selected by the present invention are used to construct rare earth complexes, and these ligands bring structural rigidity and porosity to the assembled coordination framework. From the perspective of spectroscopy, the aromatic carboxylate ligands can effectively transfer energy to metal ion sensitized photoluminescence through the "antenna" effect, thereby improving the quantum efficiency of the framework. In addition, the terpyridine ligands are introduced into the system as auxiliary ligands to meet the requirements of high coordination number, electron donor properties, conjugation and plane or space of the complex, resulting in different arrangements of the complex, thereby enriching the structure of the rare earth complex.
[0033] 4) The rare earth complex fluorescent material of the present invention has good thermal stability and excellent fluorescence performance, and a long fluorescence lifetime of up to 1.318 ms. It is a potential fluorescent sensing material and can be widely used in the fields of fluorescence sensing and the like. BRIEF DESCRIPTION OF THE DRAWINGS
[0034] Figure 1 This is the molecular structure diagram of the complex [Tb(2-Cl-6-FBA)3(4-OH-terpy)(EtO)]·0.75EtOH.
[0035] Figure 2 PXRD diffraction patterns of the ligand and the complex.
[0036] Figure 3 It is the TG-DTG curve of the complex.
[0037] Figure 4 are the excitation and emission spectra of the complex.
[0038] Figure 5 is the fluorescence lifetime decay curve of the complex. DETAILED DESCRIPTION
[0039] The present invention is further described below with reference to the examples. The description of the technical features described below is based on representative embodiments and specific examples of the present invention, but the present invention is not limited to these embodiments and specific examples. It should be noted that:
[0040] Unless otherwise stated, the units used in this specification are all international standard units, and the numerical values and numerical ranges appearing in the present invention should be understood to include the inevitable systematic errors in industrial production.
[0041] In this specification, the numerical range expressed using "a numerical value A to a numerical value B" means a range including the endpoints numerical values A and B.
[0042] In the present specification, a numerical range expressed using "above" or "below" means a numerical range including the number.
[0043] In this specification, the word "may" means both performing a certain process and not performing a certain process.
[0044] In this specification, the use of "optional" or "optional" indicates that certain substances, components, execution steps, application conditions and other factors are used or not used.
[0045] In this specification, when "normal temperature" or "room temperature" is used, the temperature may be 15-25°C.
[0046] In this manual, the reagents or instruments used without indicating the manufacturer are all conventional products that can be obtained through commercial purchase.
[0047] Example 1
[0048] This embodiment discloses a rare earth complex fluorescent material, whose chemical formula is: [Tb(2-Cl-6-FBA)3(4-OH-terpy)(EtO)]·0.75EtOH, 2-Cl-6-FBA is deprotonated 2-chloro-6-fluorobenzoic acid, 4-OH-terpy is 4-hydroxy-2,2':6',2"-terpyridine, EtO is deprotonated ethanol, and the coordination number of the rare earth element corresponding to the rare earth complex fluorescent material is 9.
[0049] The preparation method of the rare earth complex fluorescent material is as follows:
[0050] Step (1), weigh 2-chloro-6-fluorobenzoic acid (0.6 mmol) and 4-hydroxy-2,2':6',2"-terpyridine (0.2 mmol) and place them in a beaker, then add 6 mL of 95% ethanol and stir with a magnetic stirrer to completely dissolve the ligand.
[0051] Step (2), then use 1 mol L -1 The pH value of the ligand solution was adjusted to 5.8-6.4 with NaOH solution. Rare earth inorganic salt (0.2 mmol) was weighed and placed in another clean beaker, and then dissolved with 3 mL of ultrapure water.
[0052] Step (3), slowly pouring the above ligand solution into the rare earth inorganic salt solution under ultrasonic conditions, and continuing to ultrasonicate the mixed solution for 80 minutes to allow it to fully react.
[0053] Step (4), after the reaction solution was allowed to stand for 12 hours, vacuum filtration was performed using a Buchner funnel. The resulting complex powder was washed with 95% ethanol and vacuum filtered three times, and then placed in an infrared drying oven for drying for 3 hours to prepare a rare earth complex fluorescent material.
[0054] Step (5), the obtained filtrate is placed in a small beaker with a slightly scratched bottom, covered with a layer of plastic wrap with small holes, and allowed to stand at room temperature to culture a single crystal of a rare earth complex fluorescent material, and a single crystal of a rare earth complex fluorescent material is obtained after about 24 hours.
[0055] Example 2
[0056] This embodiment discloses a rare earth complex fluorescent material, whose chemical formula is: [Tb(2-Cl-6-FBA)3(4-OH-terpy)(EtO)]·0.75EtOH, wherein Tb is Tb, 2-Cl-6-FBA is deprotonated 2-chloro-6-fluorobenzoic acid, 4-OH-terpy is 4-hydroxy-2,2':6',2"-terpyridine, and EtO is deprotonated ethanol. The rare earth element coordination number corresponding to the rare earth complex fluorescent material is 9.
[0057] The preparation method of the rare earth complex fluorescent material is as follows:
[0058] Step (1), weigh 2-chloro-6-fluorobenzoic acid (3 mmol) and 4-hydroxy-2,2':6'2"-terpyridine (1 mmol) and place them in a beaker, then add 40 mL of 95% ethanol, and stir with a magnetic stirrer to completely dissolve the ligand.
[0059] Step (2), then use 1 mol L -1 The pH value of the ligand solution was adjusted to 5.8-6.4 with NaOH solution. Rare earth inorganic salt (1 mmol) was weighed and placed in another clean beaker, and then dissolved with 12 mL of ultrapure water.
[0060] Step (3), slowly pouring the above ligand solution into the rare earth inorganic salt solution under ultrasonic conditions, and continuing to ultrasonicate the mixed solution for 120 minutes to allow it to fully react.
[0061] Step (4), after the reaction solution was allowed to stand for 12 hours, vacuum filtration was performed using a Buchner funnel. The resulting complex powder was washed with 95% ethanol and vacuum filtered three times, and then placed in an infrared drying oven for drying for 3 hours to prepare a rare earth complex fluorescent material.
[0062] Step (5), the obtained filtrate is placed in a small beaker with a slightly scratched bottom, covered with a layer of plastic wrap with small holes, and allowed to stand at room temperature to culture a single crystal of a rare earth complex fluorescent material, and a single crystal of a rare earth complex fluorescent material is obtained after about 24 hours.
[0063] The characterization method of the rare earth complex fluorescent material synthesized in the above example is as follows: the composition of the complex is characterized by elemental analysis, the measured values of elemental analysis (%, calculated values) are: H, 3.09 (3.02); C, 46.21 (46.96); N, 4.06 (4.16); the structure and phase purity of the complex are characterized by single crystal X-ray diffraction and X-ray powder diffraction; the thermal stability of the complex is characterized by a thermogravimetric analyzer; and the fluorescence properties of the complex are characterized by fluorescence spectroscopy.
[0064] Figure 1 The molecular structure diagram of the complex [Tb(2-Cl-6-FBA)3(4-OH-terpy)(EtO)]·0.75EtOH. Figure 1 The complex shown is a mononuclear molecule, each structural unit contains a central metal Tb 3+ion, three 2-Cl-6-FBA ligands, one 4-OH-terpy ligand, one coordinated ethanol molecule and 0.75 free solvent ethanol molecules. Nine coordinated atoms surround the central metal ion, of which the first type of oxygen atoms (O1, O2, O3, O4) come from two 2-Cl-6-FBA ligands and are bidentate chelate coordination. The second type of oxygen atoms (O5, O8) are monodentate coordinated, coming from the 2-Cl-6-FBA ligand and the coordinated ethanol molecule, respectively. And the three nitrogen atoms N1, N2 and N3 in the neutral ligand 4-OH-terpy.
[0065] Figure 2 The PXRD diffraction patterns of the ligand and the complex are shown in the figure. As shown in the figure, the diffraction peaks of the two ligands are significantly different from those of the complex, indicating that coordination occurs between the ligand and the central metal ion, rather than simple mechanical mixing. The simulated diffraction pattern of the complex is completely consistent with the experimental diffraction pattern, indicating that their structures are the same and the complex is pure and free of impurities.
[0066] Figure 3 The TG-DTG curve of the complex is shown in Figure 2. The thermal stability of the complex at 25-800°C was studied at a linear heating rate of 10°C / min. Figure 3 As shown in FIG. 1 , it can be seen from the DTG curve of the complex that in a nitrogen atmosphere and within a selected temperature range, the decomposition of the complex is mainly divided into four steps, and the first step of decomposition starts at about 90° C. This indicates that the complex has good thermal stability.
[0067] Figure 4 The fluorescence spectra of the complex: excitation spectrum (a) and emission spectrum (b); the photoluminescence properties of the complex were studied at room temperature. A broad absorption band was observed in the excitation spectrum (a), which was attributed to the π-π* electronic transition of the organic ligand. The emission spectrum (b) was obtained with 345nm as the excitation wavelength. Specifically, there are four emission peaks at 490nm, 545nm, 585nm, and 625nm, which come from the trivalent terbium ion. 5 D4 excited state to 7 F J Radiative relaxation of (J = 6, 5, 4 and 3) [ 5 D4→ 7 F6(490nm), 5 D4→ 7 F5(545nm), 5 D4→ 7 F4(585nm) and 5 D4→ 7 F3 (625nm)]. 5 D4→ 7The emission peak intensity of F5 is the largest, which is the reason why the complex exhibits strong green photoluminescence.
[0068] Figure 5 is the fluorescence lifetime decay curve of the complex. As can be seen from the figure, the fluorescence lifetime of the complex was experimentally measured and the fluorescence lifetime decay curve was obtained. The fitted curve satisfies the double exponential function
[0069] I(t)=B1exp(-t / τ1)+B2exp(-t / τ2), the result is highly fitted. The fluorescence lifetime calculation formula τ=(B1τ1 2 +B2τ2 2 ) / (B1τ1+B2τ2) calculated that the fluorescence lifetime of the complex is 1.318ms.
[0070] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.
Claims
1. A rare earth complex fluorescent material, characterized in that: Its chemical formula is: [Tb(2-Cl-6-FBA)3(4-OH-terpy)(EtO)]·0.75EtOH, wherein Tb is a rare earth element, 2-Cl-6-FBA is deprotonated 2-chloro-6-fluorobenzoic acid, 4-OH-terpy is 4-hydroxy-2,2':6',2"-terpyridine, and EtO is deprotonated ethanol. The coordination number of the rare earth element corresponding to the rare earth complex fluorescent material is 9.
2. The rare earth complex fluorescent material according to claim 1, characterized in that: The fluorescence lifetime is as long as 1.0-1.318ms.
3. An ultrasonic synthesis method for the rare earth complex fluorescent material according to claim 1 or 2, characterized in that: The following steps are involved: Step (1), preparation of ligand solution: dissolving ligand 1 and ligand 2 in ethanol to prepare a ligand solution; then adjusting the pH of the ligand solution to 5.0-6.8; the ligand 1 is one of the halogenated benzoic acids, and the ligand 2 is one of the terpyridines; Step (2), preparing a rare earth inorganic salt solution: dissolving a rare earth inorganic salt in deionized water to prepare a rare earth inorganic salt solution; Step (3), ultrasonic synthesis: under ultrasonic conditions, the rare earth inorganic salt solution is added dropwise to the ligand solution to obtain a rare earth complex precipitate; Step (4), filtering the rare earth complex precipitate, washing with ethanol, and drying to obtain rare earth complex fluorescent material powder; Step (5), after filtering the rare earth complex precipitate, the obtained clear solution is allowed to stand to precipitate crystals, and the crystals are filtered and washed to obtain rare earth complex fluorescent material crystals.
4. The method according to claim 3, characterized in that: The halogenated benzoic acid in step (1) is 2-chloro-6-fluorobenzoic acid; And / or, the terpyridine is 4-hydroxy-2,2':6',2"-terpyridine.
5. The method according to claim 3 or 4, characterized in that: The molar ratio of ligand 1 to ligand 2 in step (1) is 1:1-1:3; And / or, the total concentration of ligands in the ligand solution is 0.1-0.3 mol / L.
6. The method according to claim 3, characterized in that: Step (1) The pH of the ligand solution is adjusted to between 5.0 and 6.8 using a 0.5-3 mol / L NaOH solution.
7. The method according to claim 3, characterized in that: The rare earth inorganic salt in step (2) is a rare earth nitrate; And / or, the concentration of rare earth inorganic salt in the rare earth inorganic salt solution in step (2) is 0.05-0.1 mol / L.
8. The method according to claim 3, characterized in that: Step (3) The rare earth inorganic salt solution is added dropwise to the ligand solution according to a molar ratio of rare earth inorganic salt to ligand of 1:1-1:
3.
9. The method according to claim 3, characterized in that: In step (3), the ultrasonic power is 50-100 W, and the ultrasonic time is 20-120 min.
10. Use of the rare earth complex fluorescent material according to claim 1 or 2 in the fields of lighting, luminescent probes and sensors.