Chiral rare earth europium metal organic framework material as well as preparation method and application thereof

Abstract

The invention provides a chiral rare earth europium metal organic framework material and a preparation method and application thereof, and belongs to the technical field of luminescent materials, the chemical formula of the chiral rare earth europium metal organic framework material is [Eu2 (RR-L) 1.5 (H2O)] n.nDMA, and RR-H2L is 4, 4 '-(1R, 2R-cyclohexane-1, 2-diacyl) bis (aminodiyl) dibenzoic acid. The invention provides a novel europium metal organic framework material (RR-Eu-MOF) with a two-dimensional layered structure as well as a preparation method and application thereof. The optical properties of the RR-Eu-MOF are as follows: the RR-Eu-MOF shows red fluorescence under the excitation of ultraviolet light with the wavelength of 383 nm; the preparation method is simple, the cost is low, chemical components are easy to control, and the repeatability is good.

Description

Technical Field

[0001] The present invention relates to the technical field of luminescent materials, and particularly relates to a chiral rare earth europium metal-organic framework material, a preparation method thereof, and an application thereof. Background Art

[0002] Metal-organic frameworks (MOFs) are three-dimensional coordination polymers formed by metal ions or metal clusters and organic ligands through self-assembly. In recent years, MOFs have received extensive attention from scientists due to their rich and variable chemical structures and excellent properties, and are widely used in gas storage and separation, heterogeneous catalysis, magnetic materials, fluorescent probes, drug delivery, and bioimaging. The porous properties of MOF materials are superior to traditional porous materials such as zeolites and carbon-based materials, because the pore channels in the framework of MOF materials can be systematically adjusted through different combinations of metal ions and organic linkers, and the functional sites in the framework can provide a platform for specific recognition.

[0003] The dissymmetry factor (g value) is one of the most important indicators for evaluating the circularly polarized luminescence (CPL) performance of chiral luminescent materials. For chiral luminescent metal-organic frameworks (LMOFs), a significant g value mainly depends on the regulation of complex and cumbersome structures and coordination environments. Therefore, it is crucial and challenging to develop a simpler and more effective strategy for enhancing the g value of chiral LMOFs. Therefore, it is necessary to design a chiral rare earth europium metal-organic framework material, a preparation method thereof, and an application thereof. Summary of the Invention

[0004] The purpose of the present invention is to provide a chiral rare earth europium metal-organic framework material, a preparation method thereof, and an application thereof, so as to solve the technical problem of low dissymmetry factor of existing metal-organic framework materials.

[0005] The present invention improves the g value of chiral Ln-MOFs by using a rare earth doping strategy, and develops a new strategy for enhancing the g value of chiral luminescent materials. In addition, this work provides a simple and effective method for preparing chiral Ln-MOFs materials with a high g value and tunable circularly polarized luminescence performance, and also opens a door for efficiently constructing chiral Ln-MOFs materials with excellent optical properties.

[0006] In order to achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0007] A chiral rare earth europium metal-organic framework material, with the chemical formula: [Eu 2 (RR-L) 1.5 (H 2 O)] n ·nDMA, wherein, RR-H 2L is 4,4'-(1R,2R-cyclohexane-1,2-dicarbonyl)bis(aminodiyl)dibenzoic acid.

[0008] Further, the metal-organic framework material RR-Eu-MOF with a two-dimensional layered structure has the molecular formula: C 70 H 71 Eu 2 N 7 O 20 , and the molecular weight is: 1634.25.

[0009] Further, RR-Eu-MOF belongs to the orthorhombic crystal system, space group C222 1 , and the unit cell parameters are α = 90°, β = 90°, γ = 90°, and the unit cell volume is Z = 4.

[0010] An application of a chiral rare earth europium metal-organic framework material, where the metal-organic framework material is used in the preparation of optical materials

[0011] A preparation method of a chiral rare earth europium metal-organic framework material. Take RR-H 2 L and Eu(NO 3 ) 3 ·6H 2 O and dissolve them in a DMA solution, then add H 2 O, place it under heating conditions for reaction. After 24 hours, transparent block crystals are formed. Separate the crystals to obtain RR-Eu-MOF.

[0012] Further, the reaction under heating conditions is that the system after adding all reactants reacts at 120 °C.

[0013] Further, the molar ratio of Eu(NO 3 ) 3 ·6H 2 O and RR-H 2 L is the stoichiometric ratio, which is 1:2.

[0014] Due to the adoption of the above technical solutions, the present invention has the following beneficial effects:

[0015] The present invention provides a new europium metal-organic framework material (RR-Eu-MOF) with a two-dimensional layered structure, its preparation method and application. The optical property of this RR-Eu-MOF is: it exhibits red fluorescence under ultraviolet light excitation with a wavelength of 383 nm; the preparation method described in the present invention is simple, low-cost, easy to control chemical components, and has good repeatability. Description of the Drawings

[0016] Figure 1The structural diagram of the RR-Eu-MOF prepared in the embodiment of the present invention;

[0017] Figure 2 The three-dimensional stacking diagram of the RR-Eu-MOF prepared in the embodiment of the present invention;

[0018] Figure 3 The room temperature fluorescence spectrum diagram of the RR-Eu-MOF prepared in the embodiment of the present invention;

[0019] Figure 4 The circular polarization spectrum diagram of the RR-Eu-MOF prepared in the embodiment of the present invention;

[0020] Figure 5 The dissymmetry factor diagram of the RR-Eu-MOF prepared in the embodiment of the present invention;

[0021] Figure 6 The RR-Eu (1-x) Tb x -MOF dissymmetry factor diagram.

[0022] Figure 7 The infrared spectrum diagram of the RR-Eu-MOF prepared in the embodiment of the present invention;

[0023] Figure 8 The solid ultraviolet diagram of the RR-Eu-MOF prepared in the embodiment of the present invention. Detailed implementation manners

[0024] To make the objectives, technical solutions and advantages of the present invention clearer, the following gives preferred embodiments with reference to the accompanying drawings and further elaborates on the present invention. However, it should be noted that many details listed in the specification are only for enabling the reader to have a thorough understanding of one or more aspects of the present invention, and these aspects of the present invention can be implemented even without these specific details.

[0025] The RR-Eu-MOF involved in the present invention is [Eu 2 (RR-L) 1.5 (H 2 O)] n ·nDMA. Among them, RR-H 2 L is 4,4'-(1R,2R-cyclohexane-1,2-dicarbonyl)bis(aminodiyl)dibenzoic acid. The preparation method of the above RR-Eu-MOF is as follows:

[0026] [Eu 2 (RR-L1) 1.5 (H 2 O)] n ·nDMA (synthesis of RR-Eu-MOF): Weigh the RR-H2 L (0.2 mmol, 82 mg) and Eu(NO 3 ) 3 ·6H 2 O (0.1 mmol, 44.6 mg,) were added to a glass bottle. Then 6 mL of DMA and 1 mL of H 2 O were added. After stirring to dissolve, it was placed in an oven at 120 °C and heated for 24 hours. Colorless block crystals were obtained. The yield was approximately 36% (calculated based on Eu(NO 3 ) 3 ·6H 2 O).

[0027] The crystal structure data of the RR-Eu-MOF are shown in Table 1, and the bond length and bond angle data are shown in Table 2.

[0028] Table 1 Crystallographic parameters of RR-Eu-MOF

[0029]

[0030] Table 2 Bond lengths of RR-Eu-MOF and bond angles (°)

[0031]

[0032] Symmetry codes: #1: 2 - X, +Y, 0.5 - Z; #2: -1 + X, +Y, +Z; #3: +X, 1 - Y, 1 - Z; #4: 1 - X, 1 - Y, -0.5 + Z;

[0033] The photophysical property studies of RR-Eu-MOF and RR-Eu (1-x) Tb x -MOF show that the complex exhibits fluorescence and circularly polarized luminescence behaviors. Therefore, the present invention also includes the application of the above RR-Eu-MOF in the preparation of optical materials.

[0034] RR-Eu (1-x) Tb x -MOF was prepared in the same way as RR-Eu-MOF, and Eu 3+ and Tb 3+ were added in proportion (x = 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9).

[0035] In the preparation method, the molar ratio of Eu(NO 3 ) 3 ·6H 2 O and RR-H 2 L is the stoichiometric ratio, usually 1:2. In the above preparation method, it is preferred that Eu(NO 3 )3 ·6H 2 O and RR-H 2 After L is dissolved with DMA, then add H 2 O.

[0036] In the preparation method, the heating mentioned usually refers to about 120 °C, the time is usually 24 hours, and the time required for complete precipitation of crystals is usually 24 hours.

[0037] Perform other characterizations on the products obtained in the examples:

[0038] 1) Crystal structure analysis:

[0039] Determine the crystal structure by measuring the surface structure intact bulk transparent crystals through single crystal diffraction. The obtained crystal structure data is shown in Table 1 as described above, the bond length and bond angle data are shown in Table 2 as described above, and the chemical structure of the obtained bulk transparent crystals is as Figure 1 shown. It is determined that the obtained bulk transparent crystals are chiral Eu metal-organic framework materials, which are europium metal-organic framework materials (RR-Eu-MOF) with a two-dimensional layered structure. Its molecular formula is: C 70 H 71 Eu 2 N 7 O 20 , and the molecular weight is: 1634.25. The three-dimensional stacking diagram of the above-mentioned bulk transparent crystals is as Figure 2 shown.

[0040] 2) Optical property measurement:

[0041] Take an appropriate amount of the crystals prepared in this example and test them on a QuantaMater 8000 type spectroscopic tester and a JASCO CPL-300 to obtain the fluorescence spectrum as Figure 3 (Fluorescence spectrum diagram of RR-Eu-MOF) and the circular polarization spectrum as Figures 4-6 (CPL, DC, and g value diagram).

[0042] It can be seen from Figures 3-6 that the RR-Eu-MOF described in the present invention emits red fluorescence under 383 nm excitation light. RR-Eu-MOF has obvious CPL emission ( Figure 4 ), the g value is 0.055 ( Figure 5 ), and the g value of the doped RR-Eu (1-x) Tb x -MOF is increased to 0.489 (x = 0.5) ( Figure 6 ), which is 8.89 times that of the undoped complex.

[0043] 3) Infrared characterization:

[0044] The RR-Eu-MOF prepared in this example was subjected to infrared analysis using a PE Spectrum Two FT-IR Fourier transform infrared spectrometer (KBr tablet), and the spectral range was 400-4000 cm -1 , and the obtained infrared spectrum is as shown in Figure 7 .

[0045] 3) UV characterization:

[0046] The RR-Eu-MOF prepared in this example was subjected to ultraviolet absorption analysis using a Shimadzu UV-2600i ultraviolet absorption spectrometer. The spectral range was 250-600 nm, and the obtained ultraviolet absorption spectrum is as shown in Figure 8 .

[0047] Matters not described in this invention are well-known techniques.

[0048] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A chiral rare earth europium metal organic framework material, characterized in that: The chemical formula is: [Eu2(RR-L) 1.5 (H2O)] n nDMA, wherein RR-H2L is 4,4'-(1R,2R-cyclohexane-1,2-diacyl)bis(aminodiyl)dibenzoic acid.

2. The chiral rare earth europium metal organic framework material according to claim 1, characterized in that: RR-Eu-MOF, a metal organic framework material with a two-dimensional layered structure, has the molecular formula: C 70 H 71 Eu2N7O 20 , molecular weight: 1634.

25.

3. A chiral rare earth europium metal organic framework material according to claim 2, characterized in that: RR-Eu-MOF belongs to the orthorhombic system, space group C2221, and the unit cell parameters are α=90°,β=90°,γ=90°,the unit cell volume is Z=4.

4. The use of a chiral rare earth europium metal organic framework material according to claim 1, characterized in that: Metal-organic framework materials are used to prepare optical materials.

5. The method for preparing a chiral rare earth europium metal organic framework material according to claim 2, characterized in that: Take RR-H2L and Eu(NO3)3·6H2O and dissolve them in DMA solution, then add H2O and react under heating conditions. After 24 hours, transparent block crystals are generated. The crystals are separated to obtain RR-Eu-MOF.

6. The method for preparing a chiral rare earth europium metal organic framework material according to claim 5, characterized in that: The reaction under heating conditions is that the system after adding all reactants is reacted at 120°C.

7. The method for preparing a chiral rare earth europium metal organic framework material according to claim 5, characterized in that: The molar ratio of Eu(NO3)3·6H2O and RR-H2L is a stoichiometric ratio of 1:2.

Images