Dynamic circular polarization luminescent material based on multi-metal oxygen cluster chiral co-assembly and preparation method and application thereof

Abstract

The invention relates to a dynamic circularly polarized luminescent material based on multi-metal oxygen cluster chiral co-assembly and a preparation method and application thereof, and belongs to the technical field of circularly polarized luminescent materials. The dynamic circular polarization luminescent material is prepared by taking a Lindeqvist type polyoxometalate compound as a chiral template and assembling the Lindeqvist type polyoxometalate compound with an achiral pyrene derivative. The spiral structure formed by the dynamic circular polarization luminescent material emits right-handed circular polarization luminescence, and dynamic regulation and control of a polyoxometalate assembly structure and circular polarization luminescence can be realized through an oxidation-reduction method based on the photochromic characteristic of the polyoxometalate. The preparation method of the dynamic circular polarization luminescent material is simple and easy to implement, simple in reaction equipment, mild in operation condition and easy to regulate and control, and can be applied to the fields of 3D display, data storage, imaging and the like.

Description

Technical Field

[0001] The present invention belongs to the technical field of circularly polarized luminescent materials, and in particular relates to a dynamic circularly polarized luminescent material based on chiral co-assembly of polymetallic oxygen clusters, and a preparation method and application thereof. Background Art

[0002] Circularly polarized luminescent materials have broad application prospects in 3D display, information encryption and chiral optoelectronic devices, and have become one of the hot topics in the research of chiral optical materials. Traditional circularly polarized luminescent materials usually achieve their specific optical activity through covalent bonding of chiral molecules. The molecular arrangement of these chiral molecules determines the properties of the circularly polarized light they emit. However, this method has problems such as high synthesis cost, difficulty in control and poor material stability, which restricts the widespread use of circularly polarized luminescent materials in practical applications.

[0003] In recent years, with the development of nanotechnology and self-assembly technology, researchers have begun to explore the use of non-covalent interactions to construct dynamic circularly polarized luminescent materials. These materials rely on the bottom-up self-assembly of chiral molecules and the cooperative co-assembly of chiral and non-chiral molecules, and use non-covalent interactions (such as π-π stacking, hydrogen bonds, van der Waals forces, etc.) to drive multi-component aggregation to form a supramolecular assembly system with a specific structure. This supramolecular structure can effectively regulate the luminescence properties of the material and achieve efficient circularly polarized luminescence activity. Non-covalent interactions have good responsiveness to external stimuli. With the help of light, temperature or pH value, the assembly and disassembly process of the supramolecular structure of dynamic circularly polarized luminescent materials can be effectively controlled, thereby changing their luminescence properties. Although dynamic circularly polarized luminescent materials have shown many excellent optical and functional properties, they still face some challenges in practical applications. How to accurately control the assembly and disassembly process of materials and achieve controllable circularly polarized luminescence performance remains a key issue. As a typical type of nanoscale inorganic anion clusters, polymetallic oxygen clusters have attracted much attention due to their potential applications in catalysis, materials and optics. Taking the unique helical assembly structure of chiral polyoxometalate complexes as chiral templates and further utilizing their excellent photochromic properties, it is expected to induce non-chiral fluorescent components to produce dynamically adjustable circularly polarized luminescence signals. Summary of the invention

[0004] In view of this, the purpose of the present invention is to provide a dynamic circularly polarized luminescent material based on chiral co-assembly of polymetallic oxygen clusters, and a preparation method and application thereof. The co-assembly system can not only emit right-handed circularly polarized luminescence, but also realize dynamic regulation of circularly polarized luminescence by alternating ultraviolet light irradiation or hydrogen peroxide oxidation; the method is simple and easy to operate, with mild operating conditions and easy regulation, and can be applied to many fields such as 3D display, data storage and imaging.

[0005] To achieve the above object, the technical solution of the present invention is as follows:

[0006] In the first aspect, the present invention provides a dynamic circularly polarized luminescent material based on chiral co-assembly of polyoxometalates, which is prepared by co-assembly of a chiral polyoxometalate complex CSEP-n and a non-chiral fluorescent dye Py-m, wherein:

[0007] The general formula of chiral polyoxometalate complex CSEP-n is (C 31 H 54 NO2T n )2[Mo6O 19 ], where: T n Alkyl carbon chain -(CH2) n -, wherein n = 5, 7, 9 or 10, the structural formula is:

[0008]

[0009] The general formula of the achiral fluorescent dye Py-m is (C3H9NA m )4C 16 H6(SO3)4, where: A m Alkyl carbon chain -C m H 2m+1 , wherein m = 1, 4, 6, 8, 10, 12, 14, 16, 17 or 18, the structural formula is:

[0010]

[0011] Furthermore, the dynamic circularly polarized luminescent material controls the photochromic process of the polymetallic oxygen clusters by ultraviolet light irradiation and hydrogen peroxide oxidation, thereby achieving dynamic regulation of the assembly structure and circularly polarized luminescence.

[0012] In a second aspect, the present invention provides a method for preparing the dynamic circularly polarized luminescent material based on chiral co-assembly of polymetallic oxygen clusters as described in the first aspect, comprising the following steps:

[0013] Step 1: Chiral cationic surfactant containing cholesterol group is reacted with (TBA)2[Mo6O 19 ] to carry out ion exchange reaction to obtain a chiral polymetallic oxygen cluster complex CSEP-n, and the reaction formula is as follows:

[0014]

[0015] Step 2: 1,3,6,8-pyrenetetrasulfonic acid tetrasodium salt and alkyltrimethylammonium bromide are ion self-assembled to obtain the non-chiral dye Py-m. The reaction formula is as follows:

[0016]

[0017] Step 3: Co-assemble the chiral polymetallic oxygen cluster complex CSEP-n and the achiral dye Py-m to obtain the dynamic circularly polarized luminescent material CSEP-n / Py-m.

[0018] Furthermore, the specific process of step 1 is as follows:

[0019] Add a chiral cationic surfactant containing a cholesterol group into acetonitrile and keep its concentration at 10-14 mg / mL; 19 ] was added to acetonitrile to maintain its concentration at 11-15 mg / mL; (TBA)2[Mo6O 19 ] acetonitrile solution is slowly added dropwise to the acetonitrile solution of the chiral cationic surfactant, and after reacting for 4-6 hours, the organic phase is separated and washed with acetonitrile for 3-5 times, and the solvent is evaporated to obtain a chiral polymetallic oxygen cluster complex CSEP-n.

[0020] Furthermore, in the step 1, the spacer group in the chiral cationic surfactant containing a cholesterol group is a straight-chain alkane having 5, 7, 9 or 10 carbon atoms.

[0021] Furthermore, the specific process of step 2 is as follows:

[0022] Dissolve alkyl trimethyl ammonium bromide in a methanol / water mixed solution and keep its concentration at 7-15 mg / mL; dissolve 1,3,6,8-pyrene tetrasulfonic acid tetrasodium salt in a methanol / water mixed solution and keep its concentration at 35-48 mg / mL; control the molar ratio of alkyl trimethyl ammonium bromide to 1,3,6,8-pyrene tetrasulfonic acid tetrasodium salt to be 3-7:1, slowly drop the 1,3,6,8-pyrene tetrasulfonic acid tetrasodium salt solution into the alkyl trimethyl ammonium bromide solution under stirring at 50-70°C, continue stirring for 2-4 hours and then centrifuge to obtain a precipitate; wash the precipitate with a methanol / water mixed solvent for 3-5 times, and then dry the precipitate under vacuum conditions to obtain a non-chiral fluorescent dye Py-m.

[0023] Furthermore, in step 2, the alkyltrimethylammonium bromide is tetramethylammonium bromide, butyltrimethylammonium bromide, hexyltrimethylammonium bromide, nonyltrimethylammonium bromide, decyltrimethylammonium bromide, dodecyltrimethylammonium bromide, tetradecyltrimethylammonium bromide, hexadecyltrimethylammonium bromide or octadecyltrimethylammonium bromide; and the volume ratio of the methanol / water mixed solution is 1-4:1.

[0024] Furthermore, the specific process of step 3 is as follows:

[0025] The chiral polymetallic oxygen cluster complex CSEP-n is added to a mixed solution of dichloromethane, isopropanol and acetonitrile, and its concentration is maintained at 0.5-6 mg / mL; the non-chiral fluorescent dye Py-m is added to the above solution, and its mass percentage is maintained at 5-15wt%; the mixed solution of the two is ultrasonicated for 10-15 minutes at room temperature to obtain a dynamic circularly polarized luminescent material CSEP-n / Py-m.

[0026] Furthermore, in step 3, the volume ratio of dichloromethane, isopropanol and acetonitrile is 5-12:0.5-1.2:0.5-1.5.

[0027] In a third aspect, the present invention provides the application of the dynamic circularly polarized luminescent material based on chiral co-assembly of polymetallic oxygen clusters described in the first aspect in 3D display, data storage and imaging, information encryption and chiral optoelectronic devices.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] (1) The present invention provides a method for preparing a chiral polyoxometalate complex CSEP-n and a non-chiral pyrene derivative fluorescent dye Py-m. The preparation method is simple, and a functional material with a fluorescent guest can be obtained by co-assembly, and the entire preparation process does not involve cumbersome synthetic operations;

[0030] (2) The helical system based on the self-assembly of chiral polyoxometalates can be co-assembled with fluorescent guests to induce the guests to obtain circularly polarized luminescent materials CSEP-n / Py-m, generating right-handed circularly polarized light;

[0031] (3) The circularly polarized luminescent material CSEP-n / Py-m can dynamically switch its circularly polarized luminescence properties by alternating ultraviolet light irradiation or hydrogen peroxide oxidation to prepare an adjustable intelligent circularly polarized luminescence switch based on photochromism. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 : H NMR spectrum of the chiral polyoxometalate complex CSEP-10 in Example 1;

[0033] Figure 2 : Infrared spectrum of the chiral polyoxometalate complex CSEP-10 in Example 1;

[0034] Figure 3 : H NMR spectrum of the achiral fluorescent dye Py-18 in Example 2;

[0035] Figure 4 : Scanning electron microscope image of the co-assembled system CSEP-10 / Py-18 (5wt%) in Example 3;

[0036] Figure 5: Circularly polarized luminescence spectrum of the initial state of the co-assembled system CSEP-10 / Py-18 (5wt%) in Example 3;

[0037] Figure 6 : Example 4: Photochromic process of the co-assembled system CSEP-10 / Py-18 (5wt%) and UV absorption spectra under different illumination times;

[0038] Figure 7 : Scanning electron microscope image and circularly polarized luminescence spectrum of the co-assembled system CSEP-10 / Py-18 (5wt%) in Example 5 after 10 minutes of UV irradiation;

[0039] Figure 8 Example 5: Co-assembly system CSEP-10 / Py-18 (5 wt%) under alternating UV irradiation and hydrogen peroxide oxidation cycles | g lum |Intensity value;

[0040] Fig. 9 : Schematic diagram of the assembly structure of the co-assembly system CSEP-10 / Py-18 (5wt%) and the dynamic regulation of the circularly polarized luminescence signal in Example 5; DETAILED DESCRIPTION

[0041] In order to facilitate the understanding of the present invention, the present invention will be described more fully below. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0042] Example 1: Synthesis of Chiral Polyoxometalate CSEP-10

[0043] The structural formula of the chiral cationic surfactant containing cholesterol groups in this embodiment is as follows:

[0044]

[0045] Chiral cationic surfactant containing cholesterol group was added into acetonitrile to maintain its concentration at 13 mg / mL; (TBA)2[Mo6O 19 ] was added to acetonitrile to maintain its concentration at 14 mg / mL; (TBA)2[Mo6O 19 ] acetonitrile solution was slowly added dropwise to the acetonitrile solution of the chiral cationic surfactant, and the organic phase was separated after 5 hours of reaction and washed with acetonitrile 4 times; the solvent was evaporated to obtain the chiral polyoxometalate complex CSEP-10. The nuclear magnetic resonance spectrum of CSEP-10 (see Figure 1 ) and infrared spectroscopy (see Figure 2) test, indicating that the chiral cationic surfactant was successfully coated on the periphery of the polyoxometalate to form a chiral polyoxometalate complex.

[0046] Example 2: Synthesis of achiral dye Py-18

[0047] The structural formula of octadecyltrimethylammonium bromide in this embodiment is as follows:

[0048]

[0049] Dissolve octadecyltrimethylammonium bromide in a methanol / water mixed solution with a volume ratio of 4:1, and keep its concentration at 10 mg / mL; dissolve 1,3,6,8-pyrenetetrasulfonic acid tetrasodium salt in another methanol / water mixed solution with a volume ratio of 4:1, and keep its concentration at 40 mg / mL; control the molar ratio of octadecyltrimethylammonium bromide to 1,3,6,8-pyrenetetrasulfonic acid tetrasodium salt to be 4:1, and slowly add the 1,3,6,8-pyrenetetrasulfonic acid tetrasodium salt solution dropwise to the octadecyltrimethylammonium bromide solution under stirring at 70°C; continue stirring for 3 hours and then centrifuge to obtain a precipitate; wash the precipitate with a methanol / water mixed solvent for 5 times, and then dry the precipitate under vacuum conditions to obtain a non-chiral fluorescent dye Py-18; Figure 3 is the NMR spectrum of Py-18, indicating the formation of achiral supramolecular compounds containing pyrene.

[0050] Example 3: Preparation of dynamic circularly polarized luminescent material CSEP-10 / Py-18

[0051] The chiral polymetallic oxygen cluster complex CSEP-10 was added to a mixed solution of dichloromethane / isopropanol / acetonitrile (10 / 1 / 1 v / v / v) to maintain its concentration at 1 mg / mL; the achiral fluorescent dye Py18 was added to the above solution to maintain its mass percentage at 5wt%; the above mixed solution was ultrasonicated at room temperature for 10 minutes to obtain the dynamic circularly polarized luminescent material CSEP-10 / Py-18.

[0052] Figure 4 a shows a scanning electron microscope image of the self-assembled system of the chiral polyoxometalate complex CSEP-10 in a mixed solution of dichloromethane / isopropanol / acetonitrile (10 / 1 / 1 v / v / v), showing a left-handed spiral morphology, corresponding to the chirality of cholesterol. Figure 4 b shows the SEM image of CSEP-10 / Py-18 when the Py-18 doping ratio is 5 wt%, which shows the left-handed spiral morphology, corresponding to the left-handed direction of the CSEP-10 self-assembly system, indicating that the addition of the fluorescent guest does not cause a change in the chiral direction. Figure 5The circularly polarized luminescence spectrum of the co-assembled system CSEP-10 / Py-18 in its initial state under 360nm light excitation was demonstrated. The results showed that the system exhibited a negative circularly polarized light signal and successfully achieved right-handed circularly polarized light emission, which was attributed to its left-handed helical structure.

[0053] Example 4: Photochromic process of the co-assembled system CSEP-10 / Py-18

[0054] Pour the CSEP-10 / Py-18 assembly solution into a quartz cell with a light path of 1 cm, and place the quartz cell vertically at a distance of 10 cm from the xenon lamp source. Control the illumination time to be 10 min. After UV illumination, the solution color gradually changes from colorless to dark blue (see Figure 6 a); Figure 6 b shows the UV absorption spectra of the co-assembled system under different illumination times. A new broad absorption band appeared at 687nm, which corresponds to the intervalence charge transfer absorption band of molybdenum, indicating the formation of reduced CSEP after UV illumination. Then, a 30wt% aqueous hydrogen peroxide solution was added dropwise to the dark blue reduced solution, and the color of the solution recovered from blue to colorless, indicating that the system was oxidized to its initial state. From the perspective of alternating UV illumination and hydrogen peroxide oxidation processes, the co-assembled system underwent a reversible photochromic process.

[0055] Example 5: Dynamic Regulation of Circularly Polarized Luminescence Signals

[0056] The colorless solution of CSEP-10 / Py-18 was poured onto a silicon substrate, and the co-assembly system was observed to form a spiral ribbon structure by scanning electron microscopy. At the same time, CSEP-10 / Py-18 emitted right-handed circularly polarized light. The CSEP-10 / Py-18 solution was poured into a quartz cell with an optical path of 1 cm, and the quartz cell was vertically placed 10 cm away from the xenon lamp light source, and the illumination time was controlled to be 10 min. During the illumination process, the color of the solution gradually changed from colorless to dark blue. The dark blue solution was then poured onto a silicon substrate, and the co-assembly system was observed to form a nanosphere structure by scanning electron microscopy (see Figure 7 a), and at the same time, the circularly polarized luminescence signal of CSEP-10 / Py-18 disappeared (see Figure 7 b); then add a 30wt% hydrogen peroxide solution to the dark blue solution, and the solution color gradually returns to colorless; then cast the colorless solution onto a silicon substrate, and the helical ribbon structure of the co-assembled system is restored, and the circularly polarized luminescence signal is restored. The optical asymmetry factor g of CSEP-10 / Py-18 lum It showed a stable reversible change, and no obvious change was found after 3 cycles of ultraviolet light and hydrogen peroxide (see Figure 8). The assembly structure of CSEP-10 / Py-18 and the schematic diagram of the dynamic regulation of circularly polarized luminescence signals are shown in Fig. 9 .

[0057] The above description is only for better explaining the embodiments of the present invention, and is not intended to limit the present invention. Any modification or equivalent substitution that does not depart from the spirit and scope of the present invention shall fall within the scope of the present invention.

Claims

1. A dynamic circularly polarized luminescent material based on chiral co-assembly of polymetallic oxygen clusters, characterized in that: It is prepared by co-assembling the chiral polymetallic oxygen cluster complex CSEP-n and the achiral fluorescent dye Py-m, wherein: The general formula of chiral polyoxometalate complex CSEP-n is (C 31 H 54 NO2T n )2[Mo6O 19 ], where: T n Alkyl carbon chain -(CH2) n -, wherein n = 5, 7, 9 or 10, the structural formula is: The general formula of the achiral fluorescent dye Py-m is (C3H9NA m )4C 16 H6(SO3)4, where: A m Alkyl carbon chain -C m H 2m+1 , wherein m = 1, 4, 6, 8, 10, 12, 14, 16, 17 or 18, the structural formula is:

2. The dynamic circularly polarized luminescent material based on chiral co-assembly of polymetallic oxygen clusters according to claim 1, characterized in that: The dynamic circularly polarized luminescent material controls the photochromic process of the polymetallic oxygen clusters by ultraviolet light irradiation and hydrogen peroxide oxidation, thereby realizing dynamic regulation of the assembly structure and circularly polarized luminescence.

3. The method for preparing a dynamic circularly polarized luminescent material based on chiral co-assembly of polymetallic oxygen clusters according to claim 1 or 2, characterized in that: The following steps are involved: Step 1: Chiral cationic surfactant containing cholesterol group is reacted with (TBA)2[Mo6O 19 ] to carry out ion exchange reaction to obtain a chiral polyoxometalate complex CSEP-n; Step 2: 1,3,6,8-pyrenetetrasulfonic acid tetrasodium salt and alkyltrimethylammonium bromide are ion self-assembled to obtain a non-chiral dye Py-m; Step 3: Co-assemble the chiral polymetallic oxygen cluster complex CSEP-n and the achiral dye Py-m to obtain the dynamic circularly polarized luminescent material CSEP-n / Py-m.

4. The method for preparing a dynamic circularly polarized luminescent material based on chiral co-assembly of polymetallic oxygen clusters according to claim 3, characterized in that: The specific process of step 1 is as follows: Add a chiral cationic surfactant containing a cholesterol group into acetonitrile and keep its concentration at 10-14 mg / mL; 19 ] was added to acetonitrile to maintain its concentration at 11-15 mg / mL; (TBA)2[Mo6O 19 ] acetonitrile solution is slowly added dropwise to the acetonitrile solution of the chiral cationic surfactant, and after reacting for 4-6 hours, the organic phase is separated and washed with acetonitrile for 3-5 times, and the solvent is evaporated to obtain a chiral polymetallic oxygen cluster complex CSEP-n.

5. The method for preparing a dynamic circularly polarized luminescent material based on chiral co-assembly of polymetallic oxygen clusters according to claim 4, characterized in that: In the step 1, the spacer group in the chiral cationic surfactant containing cholesterol groups is a straight-chain alkane with a carbon number n of 5, 7, 9 or 10.

6. The method for preparing a dynamic circularly polarized luminescent material based on chiral co-assembly of polymetallic oxygen clusters according to claim 3, characterized in that: The specific process of step 2 is as follows: Dissolve alkyl trimethyl ammonium bromide in a methanol / water mixed solution and keep its concentration at 7-15 mg / mL; dissolve 1,3,6,8-pyrene tetrasulfonic acid tetrasodium salt in a methanol / water mixed solution and keep its concentration at 35-48 mg / mL; control the molar ratio of alkyl trimethyl ammonium bromide to 1,3,6,8-pyrene tetrasulfonic acid tetrasodium salt to be 3-7:1, slowly drop the 1,3,6,8-pyrene tetrasulfonic acid tetrasodium salt solution into the alkyl trimethyl ammonium bromide solution under stirring at 50-70°C, continue stirring for 2-4 hours and then centrifuge to obtain a precipitate; wash the precipitate with a methanol / water mixed solvent for 3-5 times, and then dry the precipitate under vacuum conditions to obtain a non-chiral fluorescent dye Py-m.

7. The method for preparing a dynamic circularly polarized luminescent material based on chiral co-assembly of polymetallic oxygen clusters according to claim 6, characterized in that: In step 2, the alkyl trimethylammonium bromide is tetramethylammonium bromide, butyl trimethylammonium bromide, hexyl trimethylammonium bromide, nonyl trimethylammonium bromide, decyl trimethylammonium bromide, dodecyl trimethylammonium bromide, tetradecyl trimethylammonium bromide, hexadecyl trimethylammonium bromide or octadecyl trimethylammonium bromide; and the volume ratio of the methanol / water mixed solution is 1-4:

1.

8. The method for preparing a dynamic circularly polarized luminescent material based on chiral co-assembly of polymetallic oxygen clusters according to claim 3, characterized in that: The specific process of step 3 is as follows: The chiral polymetallic oxygen cluster complex CSEP-n is added to a mixed solution of dichloromethane, isopropanol and acetonitrile, and its concentration is maintained at 0.5-6 mg / mL; the non-chiral fluorescent dye Py-m is added to the above solution, and its mass percentage is maintained at 5-15wt%; the mixed solution of the two is ultrasonicated for 10-15 minutes at room temperature to obtain a dynamic circularly polarized luminescent material CSEP-n / Py-m.

9. The method for preparing a dynamic circularly polarized luminescent material based on chiral co-assembly of polymetallic oxygen clusters according to claim 8, characterized in that: In step 3, the volume ratio of dichloromethane, isopropanol and acetonitrile is 5-12:0.5-1.2:0.5-1.

5.

10. Application of the dynamic circularly polarized luminescent material based on chiral co-assembly of polymetallic oxygen clusters as claimed in claim 1 or 2 in 3D display, data storage and imaging, information encryption and chiral optoelectronic devices.

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