Pair of Eu-Gd-MOFs red light chiral isomer materials with circularly polarized light and preparation method of Eu-Gd-MOFs red light chiral isomer materials

Abstract

The invention relates to the technical field of crystal materials, and discloses a pair of lanthanide series MOFs red light chiral isomer materials capable of emitting circularly polarized light and a preparation method, the method comprises the following steps: taking (1R, 2R)-1, 2-cyclohexanedicarboxylic acid, (1S, 2S)-1, 2-cyclohexanedicarboxylic acid, dichloromethane and para aminobenzoic acid to synthesize a pair of enantiomeric chiral ligands R, R-CHCA and S, S-CHCA; and adding metal salt and an organic ligand R, R-CHCA or S, S-CHCA into the mixed solution, stirring, reacting at a constant temperature, cooling, crystallizing, and filtering to obtain rod-like crystals, so as to prepare crystals with P configuration and M configuration. The method has the advantages of simple synthesis process, convenient post-treatment, high yield, loose condition requirements, low cost, good repeatability and no pollution to the environment, and can be used for large-scale production; the prepared crystal product shows relatively high quantum yield, relatively high fluorescence lifetime and relatively high glum value.

Description

Technical Field

[0001] The present invention relates to the technical field of crystal materials, in particular to a pair of chiral isomerized lanthanide MOFs red light materials capable of emitting circularly polarized light and a preparation method thereof. Background Art

[0002] For a long time, those skilled in the art have relied on physical methods to generate circularly polarized light from unpolarized light. Initially, unpolarized light is linearly polarized using a polarizer, and then separated into left-handed and right-handed circularly polarized light using a quarter-wave plate. During this physical process, at least half of the energy is lost indirectly, resulting in energy waste that limits the performance of equipment, reduces its usability, and can also cause problems such as overheating. Therefore, accelerating the development of new luminescent materials that can directly generate circularly polarized light is crucial.

[0003] Chiral materials have broad application prospects in drug synthesis, chemistry, and biomedicine. Among them, chiral materials with circularly polarized luminescence (CPL) properties have particularly outstanding application potential in cutting-edge fields such as nanodevices, optical devices, and optical information storage. The indicators for evaluating the performance of CPL materials are high quantum yield and large asymmetric luminescence factor ( g lum These two parameters directly determine the luminous efficiency and polarization characteristics of the material in practical applications. Therefore, those skilled in the art have been working hard to develop materials with high quantum yield and large g lum Value of CPL material.

[0004] However, the circularly polarized luminescent materials reported so far, including organic small molecules, supramolecular compounds, polymeric materials and chiral metal organic framework materials (CMOF), all show a small g lum value, which cannot meet the needs of existing technologies.

[0005] Among them, the reported circularly polarized luminescent CMOF has potential technical advantages in improving luminous efficiency and enhancing optical properties due to its structural diversity and material adjustability. It has great application prospects in the fields of 3D display, information storage and processing, CPL laser, chiral switch and asymmetric photochemical reaction. However, the single-phase CMOF g lum The value is small, generally around 1×10 -3 Or so, or even smaller, so how to improve its g lum value, which directly affects its application prospects. Summary of the Invention

[0006] The present invention aims to solve the problem of currently using physical methods to generate circularly polarized light from non-polarized light, which leads to low energy utilization and limits the development of instruments. However, circularly polarized luminescent CMOF has potential advantages. g lum The value is small and cannot meet the demand, which affects its application prospects and other problems. A pair of lanthanide MOFs red light chiral isomer materials and preparation methods that can emit circularly polarized light are provided.

[0007] The present invention is implemented by the following technical solutions: A method for preparing a pair of lanthanide MOFs red light chiral isomer materials capable of emitting circularly polarized light comprises the following steps: a, R , R Synthesis of -CHCA Take dichloromethane and place it in a dry reactor. Add 0.71 parts of (1 R ,2 R )-1,2-cyclohexanedicarboxylic acid, the number of parts is calculated in mmol, stirred under ice bath, oxalyl chloride was added dropwise, moved to room temperature and stirred to obtain (1 R ,2 R )-cyclohexanediyl chloride, evaporate the solution to dryness, and directly add it into DMA (N, N-dimethylacetamide) to obtain (1 R ,2 R )-cyclohexanediyl chloride in DMA.

[0008] Take 1.46 parts of p-aminobenzoic acid and place it in DMA, add (1 R ,2 R )-cyclohexanediyl chloride in DMA solution, acylation reaction occurs, and then 2.14 parts of dry triethylamine are added dropwise to eliminate the acidic environment and improve the reaction efficiency and yield. The reaction is allowed to proceed overnight, and a large amount of deionized water is added to precipitate. The precipitate is filtered, and then washed with water and acetone, and dried to obtain an organic ligand. R , R -CHCA (ie 4,4'-((1 R ,2 R )-cyclohexanedicarboxamido)dibenzoic acid).

[0009] An example reaction scheme is: .

[0010] b, S,S Synthesis of -CHCA Replace (1 in step a) R ,2 R )-1,2-cyclohexanedicarboxylic acid was replaced with (1 S ,2 S)-1,2-cyclohexanedicarboxylic acid, and the remaining steps are exactly the same as step a to obtain an organic ligand S,S -CHCA (ie 4,4'-((1 S ,2 S )-cyclohexanedicarboxamido)dibenzoic acid).

[0011] An example reaction scheme is: .

[0012] Thus, a pair of enantiomeric chiral ligands were synthesized. R , R -CHCA and S,S -CHCA.

[0013] c, Gd( R,R -CHCA) 1.5 Synthesis of 0.5H2O Gd(NO3)3·6H2O and organic ligand R , R -CHCA was placed in a container, and a mixture comprising DMF, H2O and methanol was added, stirred at room temperature for 0.5 h, reacted at a constant temperature of 100°C for 3 days, cooled to room temperature until the solution showed a fully crystalline state, and filtered to obtain colorless, transparent rod-shaped crystals, thereby obtaining P-configuration crystals; d, Gd( S,S -CHCA) 1.5 Synthesis of 0.5H2O The organic ligand in step c R , R -CHCA is replaced in equal amounts with S , S -CHCA, and the remaining steps are exactly the same as step c to obtain M-configuration crystals.

[0014] Among them, the preparation method of a pair of lanthanide MOFs red light chiral isomer materials that can emit circularly polarized light specifically includes the following steps: a, R , R Synthesis of -CHCA Take 15 mL of dichloromethane and place it in a dry reactor, add 0.71 mmol of (1 R ,2 R )-1,2-cyclohexanedicarboxylic acid, stirred under ice bath, 180 μL oxalyl chloride was added dropwise, and stirred at room temperature to obtain (1 R ,2 R )-cyclohexanediyl chloride, evaporate the solution to dryness, and add the solution directly into DMA (N,N-dimethylacetamide) without purification to obtain (1 R ,2R )-cyclohexanediyl chloride in DMA; Take 1.46mmol of p-aminobenzoic acid and place it in DMA, add (1 R ,2 R )-cyclohexanediyl chloride in DMA solution, then add 2.14mmol dry triethylamine dropwise, react overnight, add a large amount of deionized water to precipitate, filter, then wash the precipitate with water and acetone, and dry to obtain the organic ligand R , R -CHCA; b, S,S Synthesis of -CHCA Replace (1 in step a) R ,2 R )-1,2-cyclohexanedicarboxylic acid was replaced with (1 S ,2 S )-1,2-cyclohexanedicarboxylic acid, and the remaining steps are exactly the same as step a to obtain an organic ligand S,S -CHCA.

[0015] c, Gd( R,R -CHCA) 1.5 Synthesis of 0.5H2O 0.01 mmol of Gd(NO3)3·6H2O and 0.03 mmol of organic ligand R , R -CHCA was placed in a reaction vessel, and a mixed solution including DMF, H2O and methanol was added. The mixture was stirred at room temperature for 0.5 h, reacted at a constant temperature of 100°C for 3 days, cooled to room temperature until the solution showed a fully crystalline state, and filtered to obtain colorless and transparent rod-shaped crystals, thereby obtaining P-configuration crystals.

[0016] d, Gd( S,S -CHCA) 1.5 Synthesis of 0.5H2O The organic ligand in step c R , R -CHCA is replaced in equal amounts with S , S -CHCA, and the remaining steps are exactly the same as step c to obtain M-configuration crystals.

[0017] According to Gd( R,R -CHCA) 1.5 0.5H2O and Gd( S,S -CHCA) 1.5Based on the synthesis principle of 0.5H2O, Gd(NO3)3·6H2O is replaced by Eu(NO3)3·6H2O and Gd(NO3)3·6H2O to obtain a pair of lanthanide MOFs red light chiral isomers that can emit circularly polarized light. The preparation method includes the following steps: Replace steps c and d above with the following steps: c, Eu 0.0495 Gd 0.9505 ( R,R -CHCA) 1.5 Synthesis of 0.5H2O Eu(NO3)3·6H2O, Gd(NO3)3·6H2O and organic ligands R , R -CHCA is placed in a container, and the sum of Eu(NO3)3·6H2O and Gd(NO3)3·6H2O is mixed with the organic ligand. R , R -CHCA is added to a mixture with a molar ratio of 1:3, wherein the mixture includes DMF, H2O and methanol, stirred at room temperature for 0.5h, reacted at a constant temperature of 100°C for 3 days, cooled to room temperature until the solution is in a fully crystalline state, filtered, and obtained colorless and transparent rod-shaped crystals, thereby obtaining P-configuration crystals; d, Eu 0.0495 Gd 0.9505 ( S,S -CHCA) 1.5 Synthesis of 0.5H2O Eu(NO3)3·6H2O, Gd(NO3)3·6H2O and organic ligands S , S -CHCA is placed in a container, and the sum of Eu(NO3)3·6H2O and Gd(NO3)3·6H2O is mixed with the organic ligand. S , S -CHCA is added in a molar ratio of 1:3, and a mixed solution including DMF, H2O and methanol is added, stirred at room temperature for 0.5h, reacted at a constant temperature of 100°C for 3 days, cooled to room temperature until the solution presents a fully crystalline state, filtered, and obtained colorless and transparent rod-shaped crystals, thereby obtaining M-configuration crystals.

[0018] Furthermore, the ratio of Eu(NO3)3·6H2O, Gd(NO3)3·6H2O and organic ligand is 99:1901:6000, where the ratio is in mmol. Specifically, a pair of Eu2O3 that can emit circularly polarized light x Gd y -The preparation method of MOFs red light chiral isomer material specifically comprises the following steps: Steps a and b are exactly the same as those of the above-mentioned GdMOFs.

[0019] c, Eu 0.0495 Gd 0.9505 ( R,R -CHCA) 1.5 Synthesis of 0.5H2O 0.000495 mmol of Eu(NO3)3·6H2O, 0.009505 mmol of Gd(NO3)3·6H2O and 0.03 mmol of organic ligand were added. R , R -CHCA is placed in a container, and the remaining steps are exactly the same as the above step c to obtain P-configuration crystals.

[0020] d, Eu 0.0495 Gd 0.9505 ( S,S -CHCA) 1.5 Synthesis of 0.5H2O 0.000495 mmol of Eu(NO3)3·6H2O, 0.009505 mmol of Gd(NO3)3·6H2O and 0.03 mmol of organic ligand were added. S , S -CHCA is placed in a container, and the remaining steps are exactly the same as the above step c to obtain M-configuration crystals.

[0021] The present invention also discloses a pair of lanthanide MOFs red light chiral isomer materials capable of emitting circularly polarized light, including the lanthanide MOFs red light material capable of emitting circularly polarized light prepared according to the above method.

[0022] Compared with the prior art, the present invention has the following beneficial effects: The present invention provides a pair of lanthanide MOFs red light chiral isomer materials and preparation methods that can emit circularly polarized light. According to the unique optical properties of lanthanide metal coordination chiral materials, high anisotropy values are obtained, showing high glum values. Chiral ligands and lanthanide metal ions are self-assembled into chiral lanthanide MOFs (Eu x Gd y -MOFs), aiming to improve the glum value of MOFs materials.

[0023] Compared with the situation that most chiral organic ligands have many synthesis steps, complex post-processing and low yield, the preparation method provided by the present invention has simple synthesis steps, convenient and efficient post-processing process, and can effectively reduce manpower and time cost investment. The present invention adopts low-temperature hydrothermal conditions for synthesis, the process is simple and easy to operate, the requirements for reaction conditions are loose, the production threshold and technical difficulty are reduced, the cost is low, and the repeatability is good to ensure the stability of quality, which is conducive to large-scale standardized production. In addition, the synthesis process is pollution-free to the environment, conforms to the concept of green chemistry, meets the needs of industrial production, and achieves sustainable development, with broad application prospects and market potential.

[0024] Eu synthesized by the present invention 0.0495 Gd 0.9505 ( R,R- CHCA) 1.5 0.5H2O and Eu 0.0495 Gd 0.9505 ( S,S- CHCA) 1.5 0.5H2O can emit red light under ultraviolet light, has good thermal stability, chemical stability and photostability, and also shows a high quantum yield (64.3% and 61.48% respectively) and a long fluorescence lifetime (0.66 ms and 0.65 ms respectively). In addition, according to the test, this pair of crystals also shows a high g lum The values are 4.6×10 -3 and 2.5×10 -3 , exceeding that of reported single-phase MOFs g lum At the same time, its high yield can achieve efficient conversion, reduce energy waste, improve equipment performance, and thus improve economic benefits, providing a material basis with both quality and quantity for subsequent applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 Represents a crystal structure diagram.

[0026] Figure 2 Infrared spectra of the ligand and crystals.

[0027] Figure 3 Represents the crystal powder diffraction pattern.

[0028] Figure 4 Figure 2 shows the thermogravimetric analysis of MOF crystals.

[0029] Figure 5 Eu 0.0495 Gd 0.9505 ( R,R- CHCA) 1.50.5H2O (left) and Eu 0.0495 Gd 0.9505 ( S,S- CHCA) 1.5 Fluorescence excitation and emission spectra of 0.5H2O (right).

[0030] Figure 6 Eu 0.0495 Gd 0.9505 ( R,R - / S,S- CHCA) 1.5 CD spectrum of 0.5H2O.

[0031] Figure 7 Eu 0.0495 Gd 0.9505 ( R,R - / S,S- CHCA) 1.5 CPL spectrum of 0.5H2O. DETAILED DESCRIPTION

[0032] Specific embodiments of the present invention will be described below with reference to the accompanying drawings.

[0033] Preparation method of a pair of lanthanide MOFs red light chiral isomer materials that can emit circularly polarized light. In this embodiment, the lanthanide MOFs is Eu x Gd y -MOFs, including the following steps: a, R , R Synthesis of -CHCA Take 15 mL of dichloromethane and place it in a dry single-necked round-bottom flask, add 122 mg of (1 R ,2 R )-1,2-cyclohexanedicarboxylic acid, stirred under ice bath, 180 μL oxalyl chloride was added dropwise, and stirred at room temperature to obtain (1 R ,2 R )-cyclohexanediyl chloride, evaporate the solution to dryness, and directly add it into DMA to obtain (1 R ,2 R )-cyclohexanediyl chloride in DMA; Take 200 mg of p-aminobenzoic acid and place it in DMA, add (1 R ,2 R )-cyclohexanediyl chloride in DMA, then add 296µL of dry triethylamine, react overnight, add a large amount of deionized water to precipitate, filter, wash the precipitate with water and acetone, and dry to obtain 256.8 mg of organic ligand R , R -CHCA; calculated based on the theoretical yield of the productR , R The yield of -CHCA was 88.2%.

[0034] b, S,S Synthesis of -CHCA Replace (1 in step a) R ,2 R )-1,2-cyclohexanedicarboxylic acid was replaced with (1 S ,2 S )-1,2-cyclohexanedicarboxylic acid, and the remaining steps are exactly the same as step a to obtain an organic ligand S,S -CHCA; c, Eu 0.0495 Gd 0.9505 ( R,R - CHCA) 1.5 Synthesis of 0.5H2O 0.221 mg of Eu(NO3)3·6H2O, 4.29 mg of Gd(NO3)3·6H2O and 12.4 mg of organic ligand were added. R , R -CHCA was placed in a glass vial, and a mixture of DMF, H2O, and methanol was added. The mixture was stirred at room temperature for 0.5 h, and reacted at a constant temperature of 100°C for 3 days. The mixture was cooled to room temperature until the solution showed a fully crystalline state. The mixture was filtered to obtain colorless, transparent rod-shaped crystals, and P-configuration crystals were obtained. The calculated yield was 65%.

[0035] d, Eu 0.0495 Gd 0.9505 ( S,S - CHCA) 1.5 Synthesis of 0.5H2O The organic ligand in step c of this embodiment R , R -CHCA is replaced in equal amounts with S , S -CHCA, and the remaining steps are exactly the same as step c to obtain M-configuration crystals.

[0036] Specifically, 0.221 mg of Eu(NO3)3·6H2O, 4.29 mg of Gd(NO3)3·6H2O and 12.4 mg of organic ligand were added. S , S -CHCA was placed in a glass vial, and a mixture of DMF, H2O and methanol was added. The mixture was stirred at room temperature for 0.5 h, and reacted at a constant temperature of 100°C for 3 days. The mixture was cooled to room temperature until a fully crystalline state appeared in the solution. The mixture was filtered to obtain colorless, transparent rod-shaped crystals, and M-configuration crystals were obtained.

[0037] The obtained crystal structure is as Figure 1 As shown, Gd in GdMOF 3+ Ions and ligands (1 R ,2 R )-1,2-cyclohexanedicarboxylic acid coordination environment diagram and multi-channel two-dimensional layer diagram. Figure 1 It can be seen that in a crystallographically independent space, there is 1 and a half Gd 3+ ions and 1 and a half (1 R ,2 R )-1,2-cyclohexanedicarboxylic acid ligand, the ligand shows a two-linked structure, and through the Gd-O-Gd cluster and ligand coordination, a multi-channel two-dimensional layered infinite network structure is constructed. Figure 3 The crystal powder diffraction pattern of Eu 0.0495 Gd 0.9505 ( R,R -CHCA) 1.5 0.5H2O, Eu 0.0495 Gd 0.9505 ( S,S - CHCA) 1.5 The crystal powder diffraction curve of 0.5H2O is highly consistent with the respective crystal structure simulation curves, which shows that the synthesized Gd x Eu y -MOFs have a highly ordered and stable lattice structure with excellent phase purity.

[0038] The absorption intensity of infrared light of the prepared sample is measured to obtain an infrared spectrum, such as Figure 2 As shown in the figure, the characteristic peaks in the infrared spectrum correspond to the specific functional groups and chemical bonds in the sample, which shows that the original functional groups of the chiral ligands are retained during the synthesis process, and the structure of the MOFs material remains stable, verifying the chiral ligands ( R , R - / S , S -CHCA) were successfully introduced into the MOFs framework without chemical bond breakage or isomerization. R , R and S , S configuration) can precisely control the chiral microenvironment of the material, providing a design basis for enantioselective chiral switches, etc.

[0039] like Figure 4 As shown, the skeleton structure decomposes at around 300~400℃, has high thermal stability, can be used in high temperature environment, and has good thermal stability.

[0040] like Figure 5As shown, the Eu synthesized in this application 0.0495 Gd 0.9505 ( R,R- CHCA) 1.5 0.5H2O (left) and Eu 0.0495 Gd 0.9505 ( S,S- CHCA) 1.5 0.5H2O (right) emits red light under UV light. Using an integrating sphere test, the quantum yields calculated were 64.3% and 61.48%, respectively, demonstrating high quantum yields.

[0041] like Figure 6 It was confirmed that MOFs materials successfully obtained chiral crystals by introducing chiral ligands. Figure 7 As shown in the figure, the synthesized material has significant chiral red light emission characteristics, and the emission intensity of left-handed and right-handed circularly polarized light is significantly different, which meets the requirements of CPL material performance. g lum The values are 4.6×10 -3 and 2.5×10 -3 , while single-phase MOFs g lum The value is 1×10 -3 The glum value of the material prepared by the present invention exceeds that of the reported single-phase MOFs. g lum value.

[0042] The scope of protection claimed by the present invention is not limited to the above specific embodiments. For those skilled in the art, the present invention may have various variations and modifications. Any modifications, improvements and equivalent substitutions made within the concept and principle of the present invention should be included in the scope of protection of the present invention.

Claims

1. A pair of Eu-Gd-MOFs red light chiral isomer materials capable of emitting circularly polarized light and a preparation method, characterized in that: The following steps are involved: a, R , R Synthesis of -CHCA Take dichloromethane and place it in a dry reactor. Add 0.71 parts of (1 R ,2 R )-1,2-cyclohexanedicarboxylic acid, the number of parts is calculated in mmol, stirred under ice bath, oxalyl chloride was added dropwise, moved to room temperature and stirred to obtain (1 R ,2 R )-cyclohexanediyl chloride, evaporate the solution to dryness, and add directly into DMA to obtain (1 R ,2 R )-cyclohexanediyl chloride in DMA; Take 1.46 parts of p-aminobenzoic acid and place it in DMA, add (1 R ,2 R )-cyclohexanediyl chloride DMA solution, then add 2.14 parts of dry triethylamine dropwise, react overnight, add a large amount of deionized water to precipitate, filter, then wash the precipitate with water and acetone, and dry to obtain an organic ligand R , R -CHCA; b, S,S Synthesis of -CHCA Replace (1 in step a) R ,2 R )-1,2-cyclohexanedicarboxylic acid was replaced with (1 S ,2 S )-1,2-cyclohexanedicarboxylic acid, and the remaining steps are exactly the same as step a to obtain an organic ligand S,S -CHCA; c, Eu 0.0495 Gd 0.9505 ( R,R -CHCA) 1.5 Synthesis of 0.5H2O Eu(NO3)3·6H2O, Gd(NO3)3·6H2O and organic ligands R , R -CHCA was placed in a container, and a mixture comprising DMF, H2O and methanol was added, stirred at room temperature for 0.5 h, reacted at a constant temperature of 100°C for 3 days, cooled to room temperature until the solution showed a fully crystalline state, and filtered to obtain colorless, transparent rod-shaped crystals, thereby obtaining P-configuration crystals; d, Eu 0.0495 Gd 0.9505 ( S,S -CHCA) 1.5 Synthesis of 0.5H2O Eu(NO3)3·6H2O, Gd(NO3)3·6H2O and organic ligands S , S -CHCA was placed in a container, and a mixed solution including DMF, H2O and methanol was added. The mixture was stirred at room temperature for 0.5 h, reacted at a constant temperature of 100°C for 3 days, cooled to room temperature until the solution showed a fully crystalline state, and filtered to obtain colorless and transparent rod-shaped crystals, thereby obtaining M-configuration crystals.

2. The method for preparing a pair of lanthanide MOFs red light chiral isomer materials capable of emitting circularly polarized light according to claim 1, characterized in that: In steps c and d, the sum of Eu(NO3)3·6H2O and Gd(NO3)3·6H2O and the organic ligand R , R -CHCA or S , S The molar ratio of -CHCA is 1:

3.

3. The method for preparing a pair of lanthanide MOFs red light chiral isomer materials capable of emitting circularly polarized light according to claim 1, characterized in that: In step c and step d, the ratio of Eu(NO3)3·6H2O, Gd(NO3)3·6H2O and organic ligand is 99:1901:6000, and the ratio is in mmol.

4. The method for preparing a pair of lanthanide MOFs red light chiral isomer materials capable of emitting circularly polarized light according to claim 1, characterized in that: In step a, add 180 µL of oxalyl chloride dropwise per 15 mL of dichloromethane.

5. A pair of lanthanide MOFs red light chiral isomer materials capable of emitting circularly polarized light, characterized in that: The invention comprises a lanthanide MOFs red light material capable of emitting circularly polarized light and prepared according to the method of claim 1.

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