Low-temperature photochromic chiral ionic hydrogen bond organic framework material as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of hydrogen bond organic framework materials, and relates to a low-temperature photochromic chiral ionic hydrogen bond organic framework material, the chemical formula is [(H4TPE) 2 (R / S-DPEN) 4. (CH3OH) 7H2O] n, n is a positive integer, H4TPE is tetra (4-sulfophenyl) ethylene, and R / S-DPEN is R / S-diphenyl ethylenediamine. The structural unit belongs to a monoclinic system, the space group is P21, and the molecular formula is C115H134N8O32S8. The preparation method comprises the following steps: dissolving the H4TPE ligand and the R / S-DPEN ligand in a methanol solution to obtain a reaction solution; and carrying out sealing and heat preservation on the reaction liquid at room temperature to obtain colorless transparent rod-like crystals, filtering and drying to obtain the chiral ionic hydrogen bond organic framework material. The material has good stability and reversibility, and can be applied to the aspects of information encryption, 3D intelligent display, photoetching printing and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of hydrogen-bonded organic framework materials, and in particular relates to a low-temperature photochromic chiral ionic hydrogen-bonded organic framework material and a preparation method and application thereof. Background Art

[0002] In low-temperature environments, ordinary encryption display materials will have problems such as slow information recording and incomplete or failed decoding, which makes it impossible to quickly and accurately realize information entry and transmission. Unfortunately, this problem has not received widespread attention. Therefore, it is particularly important to realize the functional expansion and specific multiple encryption applications of encryption materials. In particular, the development of reversible on-demand multifunctional light-responsive encryption materials in low-temperature environments is imminent. Photochromism and circularly polarized luminescence (CPL) are two important branches in the field of optical functions. They are widely used in information encryption, 3D smart display, photolithography, etc. Photochromic materials are responsive materials that undergo reversible color / morphological changes when subjected to external stimuli (light, temperature, pressure, pH, etc.). It is considered to be one of the most promising smart material candidates for future multiple advanced encryption and anti-counterfeiting. At present, most photochromic materials are single-response materials, which are supramolecular polymers formed by one optically active unit; for example, azobenzene, cyclodextrin, spiropyran, etc. They mainly have the disadvantages of single encryption level, limited adjustable functions, no discoloration at low temperatures or poor environmental applicability. In addition, traditional fluorescent materials exhibit varying degrees of quenching effects in the solid state, which limits their application in diverse scenarios.

[0003] Common traditional crystalline materials include metal organic frameworks (MOFs) and covalent organic frameworks (COFs), which have the advantages of good porosity, high stability (thermal / chemical), easy surface functionalization, etc., and are widely used in the development and application of optical materials. Nowadays, a new class of materials, hydrogen-bonded organic frameworks (HOFs), have unique advantages such as mild preparation conditions, good solution processability, better self-healing and regeneration ability, biocompatibility and low cytotoxicity. Hydrogen-bonded organic frameworks (HOFs) have abundant hydrogen bond receptors and diverse structural frameworks, which are different from metal organic frameworks (MOFs) and covalent organic frameworks (COFs). It can show different light attenuation paths through molecular conjugation, protonation effect, charge transfer and reversible structural transformation. In addition, the bond energy of hydrogen bonds is lower than that of metal bonds and covalent bonds, which may make it easier to achieve bond breaking and secondary bonding at local sites to achieve further precise regulation of material properties. Therefore, HOFs will become a favorable candidate for multifunctional optical materials and show great development potential in information storage and multiple encryption.

[0004] Most of the research focuses on the development of temperature-gated responsive photochromic encryption materials activated at room temperature or high temperature. Low-temperature responsive functional materials have huge demand and broad application prospects under extreme environmental conditions such as bio-labeling and imaging, low-temperature intelligent display, information anti-counterfeiting encryption, and virus storage. In particular, photochromic circularly polarized luminescent crystalline hydrogen-bonded organic framework materials with dual switching under low-temperature activation have not yet been developed. Summary of the invention

[0005] One of the purposes of the present invention is to provide a low-temperature photochromic chiral ionic hydrogen-bonded organic framework material and a preparation method thereof, in order to develop a fast-response optical encryption material suitable for use in a low-temperature environment.

[0006] The second purpose of the present invention is to provide an application of a low-temperature photochromic chiral ionic hydrogen-bonded organic framework material, which can develop on-demand reversible multiple stimulus-responsive encryption materials at low temperatures.

[0007] The present invention is achieved through the following technical solutions:

[0008] The invention discloses a low-temperature photochromic chiral ionic hydrogen-bonded organic framework material, the chemical formula of which is: [(H4TPE)2(R / S-DPEN)4·(CH3OH)7H2O] n , wherein n is a positive integer, H4TPE is tetrakis(4-phenylsulfonate)ethylene, and R / S-DPEN is R / S-diphenylethylenediamine.

[0009] Furthermore, the structural unit of the chiral ionic hydrogen-bonded organic framework material belongs to the monoclinic system, the space group is P21, and the molecular formula is C 115 H 134 N8O 32 S8, unit cell parameters: α=90.00, β=90.3438(8), γ=90.00,

[0010] Furthermore, the chiral ionic hydrogen-bonded organic framework material is polymerized by a plurality of repeating units, and each repeating unit contains two H4TPEs, four R / S-DPENs, one lattice water molecule and seven methanol molecules.

[0011] Furthermore, the R / S-DPEN ligands are arranged alternately to form an organic ligand layer, and H4TPE is embedded in the pores of the R / S-DPEN ligand layer. The adjacent sulfonic acid groups, amino groups, water molecules, and methanol molecules are connected together by hydrogen bonding interactions to form a three-dimensional (3D) supramolecular structure in a π-π stacking manner.

[0012] Methanol molecules and water molecules connect R / S-DPEN and H4TPE to form a network of hydrogen bonds.

[0013] Furthermore, the chiral ionic hydrogen-bonded organic framework material is a porous material with high structural stability, and can still maintain its original framework structure after being immersed in water for three days.

[0014] Furthermore, the thermal stability decomposition temperature of the chiral ionic hydrogen-bonded organic framework material reaches 280°C.

[0015] Furthermore, the chiral ionic hydrogen-bonded organic framework material has no photochromic phenomenon at room temperature and under 365nm ultraviolet light, and changes from a white solid powder to a red solid powder at -20°C and under 365nm ultraviolet light;

[0016] The chiral ionic hydrogen-bonded organic framework material exhibits g lum = ±1.7 × 10 -3 The asymmetry factor of circularly polarized luminescence; g lum = ±3.1 × 10 -3 Asymmetry factor of circularly polarized luminescence.

[0017] The present invention also discloses a method for preparing the low-temperature photochromic chiral ionic hydrogen-bonded organic framework material, which comprises the following steps:

[0018] 1) dissolving H4TPE ligand and R / S-DPEN ligand in a mixed solution of water and methanol at a molar ratio of 1:(1-4) to obtain a reaction solution; wherein the molar ratio of water to methanol is 1:(1-2);

[0019] 2) The reaction solution obtained in step 1) is sealed and kept warm at room temperature for 3 to 5 days to obtain colorless transparent rod-shaped crystals, which are filtered and dried naturally to obtain a low-temperature photochromic chiral ionic hydrogen-bonded organic framework material.

[0020] The present invention also discloses the application of the chiral ionic hydrogen-bonded organic framework material, preparing the chiral ionic hydrogen-bonded organic framework material into a polymer matrix composite film, and applying the polymer matrix composite film to multiple stimulus information encryption, 3D intelligent display or photolithography printing.

[0021] Furthermore, the specific steps of preparing the chiral ionic hydrogen-bonded organic framework material into a polymer matrix composite membrane are:

[0022] Dispersing the chiral ionic hydrogen-bonded organic framework material in water, mixing and stirring to obtain a suspension;

[0023] The polyvinyl alcohol solution is added to the suspension, and the mixture is continuously stirred at room temperature to obtain a uniform solution; the mixed solution is applied to a silica glass substrate and dried to remove the solvent to obtain a polymer matrix composite film.

[0024] Compared with the prior art, the present invention has the following beneficial technical effects:

[0025] The present invention discloses a low-temperature photochromic chiral ionic hydrogen-bonded organic framework material. The material mainly selects sulfonic acid ligands with aggregation-induced emission (AIE) centers. Compared with the polymer materials with azobenzene and spiropyran as luminescence / color change centers that have been studied more in the past, the most important innovation is that this is a new type of chiral ionic hydrogen-bonded organic framework material, and the single crystal structure is more conducive to accurate research on the intrinsic mechanism of luminescence and color change. In addition, most fluorescent materials have aggregation-induced quenching in the solid state, which greatly limits the application form of the material. The chiral ionic hydrogen-bonded organic framework material uses TPE as the optical center and still has a high quantum yield in the solid state. The HOF prepared by the present invention eventually forms a two-dimensional mesh hydrogen bond network. This two-dimensional framework is conducive to the transmission of photoelectrons and has a certain stability. The PXRD powder diffraction analysis data shows that the obtained product has a high purity, and the thermogravimetric analysis shows that the thermal stability is high. The decomposition temperature of the porous framework is 280°C. At the same time, it does not change color under ultraviolet irradiation at room temperature, changes color quickly under ultraviolet irradiation at a low temperature of -20°C and has a high circularly polarized luminescence asymmetry factor. It is a new type of multi-response encryption application material.

[0026] The invention also discloses a method for preparing the low-temperature photochromic chiral ionic hydrogen-bonded organic framework material, which is prepared from H4TPE and R / S-DPEN. The synthetic raw materials are easily available, and a solution method is used to cultivate crystals. The preparation process is simple, the operation is convenient, and the yield is high.

[0027] When the hydrogen bond organic framework of the present invention is used as a dual-stimulus multifunctional optical encryption material, there is no photochromic phenomenon under 365nm ultraviolet light at room temperature; it quickly changes from a white solid powder to a red solid powder under 365nm ultraviolet light at -20°C. At room temperature, it shows g lum = ±1.7 × 10 -3 The asymmetry factor of the circularly polarized luminescence (CPL) is shown at 460 nm at -20 °C. lum = ±3.1 × 10 -3 The asymmetry factor of the circularly polarized luminescence (CPL).

[0028] The low-temperature photochromic chiral ionic hydrogen-bonded organic framework material disclosed in the present invention has broad application prospects in information encryption, 3D intelligent display, photolithography printing, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a schematic diagram of the asymmetric unit of the hydrogen-bonded organic framework material synthesized in Example 4 of the present invention;

[0030] Figure 2 This is a schematic diagram of the asymmetric unit of the chiral hydrogen-bonded organic framework material synthesized in Example 4 of the present invention;

[0031] Figure 3 The two-dimensional hydrogen bond network structure of the hydrogen bond organic framework material synthesized in Example 4 of the present invention;

[0032] Figure 4 A schematic diagram of the three-dimensional supramolecular structure of the hydrogen-bonded organic framework material synthesized in Example 4 of the present invention;

[0033] Figure 5 The X-ray powder diffraction pattern of the hydrogen-bonded organic framework material crystal synthesized in Example 4 of the present invention;

[0034] Figure 6 The solvent-controlled framework recovery X-ray powder diffraction pattern of the hydrogen-bonded organic framework material crystal synthesized in Example 4 of the present invention;

[0035] Figure 7 This is a thermogravimetric analysis diagram of the hydrogen-bonded organic framework material crystal synthesized in Example 4 of the present invention;

[0036] Figure 8 This is a low-temperature photochromic ultraviolet spectrum of the hydrogen-bonded organic framework material synthesized in Example 4 of the present invention;

[0037] Fig. 9 This is a room temperature-low temperature photochromic reversibility cycle diagram of the hydrogen-bonded organic framework material synthesized in Example 4 of the present invention;

[0038] Fig.10 This is a low temperature EPR spectrum of the hydrogen bonded organic framework material synthesized in Example 4 of the present invention;

[0039] Fig.11 The fluorescence spectrum of the hydrogen-bonded organic framework material synthesized in Example 4 of the present invention;

[0040] Fig.12 The fluorescence lifetime spectrum of the hydrogen-bonded organic framework material synthesized in Example 4 of the present invention;

[0041] Fig.13 Circular dichroism (CD) diagram of the hydrogen-bonded organic framework material synthesized in Example 4 of the present invention;

[0042] Fig.14 The circularly polarized luminescence spectrum (CPL) of the hydrogen-bonded organic framework material synthesized in Example 4 of the present invention at room temperature (25° C.);

[0043] Fig.15 A graph showing the circularly polarized luminescence asymmetry factor (glum) of the hydrogen-bonded organic framework material synthesized in Example 4 of the present invention at room temperature (25° C.);

[0044] Fig.16 The circularly polarized luminescence spectrum (CPL) of the hydrogen-bonded organic framework material synthesized in Example 4 of the present invention at low temperature (-20° C.);

[0045] Fig.17 A graph showing the circularly polarized luminescence asymmetry factor (glum) of the hydrogen-bonded organic framework material synthesized in Example 4 of the present invention at low temperature (-20°C);

[0046] Fig.18 These are photochromic photographs of the hydrogen-bonded organic framework material synthesized in Example 4 of the present invention at different temperatures. DETAILED DESCRIPTION

[0047] In order to make the purpose, technical solution and advantages of the present invention more clear, the following is further described in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention, that is, the embodiments described are only part of the embodiments of the present invention, not all embodiments.

[0048] The detailed description of the embodiments of the present invention provided in the following drawings is not intended to limit the scope of the invention claimed for protection, but merely represents a selected embodiment of the present invention. Based on the drawings and embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0049] The features and performances of the present invention are further described in detail below in conjunction with the embodiments.

[0050] The invention discloses a low-temperature photochromic chiral ionic hydrogen-bonded organic framework material, characterized in that its chemical formula is: [(H4TPE)2(R / S-DPEN)4·(CH3OH)7(H2O)1] n , wherein n is a positive integer, H4TPE is tetrakis(4-phenylsulfonate)ethylene, and R / S-DPEN is R / S-diphenylethylenediamine.

[0051] The invention also discloses a method for preparing the hydrogen-bonded organic framework material, comprising the following steps:

[0052] 1) dissolving H4TPE ligand and R / S-DPEN ligand in a mixed solution of water and methanol at a molar ratio of 1:(1-4) to obtain a reaction solution; wherein the molar ratio of water to methanol is 1:(1-2);

[0053] 2) The reaction solution obtained in step 1) is sealed and kept warm at room temperature for 3 to 5 days to obtain colorless transparent rod-shaped crystals, which are filtered and dried naturally to obtain a chiral ionic hydrogen-bonded organic framework material.

[0054] The present invention is described in further detail below in conjunction with embodiments:

[0055] Example 1

[0056] The invention discloses a method for preparing a low-temperature photochromic chiral ionic hydrogen-bonded organic framework material, comprising the following steps:

[0057] 1) dissolving H4TPE ligand and R / S-DPEN ligand in a mixed solution of water and methanol at a molar ratio of 1:1 to obtain a reaction solution; wherein the molar ratio of water to methanol is 1:2;

[0058] 2) The reaction solution obtained in step 1) is sealed and kept warm at room temperature for 3 days to obtain colorless transparent rod-shaped crystals, which are filtered and dried naturally to obtain a chiral ionic hydrogen-bonded organic framework material.

[0059] The yield of the hydrogen-bonded organic framework material obtained in this example is 50%.

[0060] Example 2

[0061] The invention discloses a method for preparing a low-temperature photochromic chiral ionic hydrogen-bonded organic framework material, comprising the following steps:

[0062] 1) dissolving H4TPE ligand and R / S-DPEN ligand in a mixed solution of water and methanol at a molar ratio of 1:4 to obtain a reaction solution; wherein the molar ratio of water to methanol is 1:1;

[0063] 2) The reaction solution obtained in step 1) is sealed and kept warm at room temperature for 5 days to obtain colorless transparent rod-shaped crystals, which are filtered and dried naturally to obtain a chiral ionic hydrogen-bonded organic framework material.

[0064] The yield of the hydrogen-bonded organic framework material obtained in this example is 60%.

[0065] Example 3

[0066] The invention discloses a method for preparing a low-temperature photochromic chiral ionic hydrogen-bonded organic framework material, comprising the following steps:

[0067] 1) dissolving H4TPE ligand and R / S-DPEN ligand in a mixed solution of water and methanol at a molar ratio of 1:3 to obtain a reaction solution; wherein the molar ratio of water to methanol is 1:1;

[0068] 2) The reaction solution obtained in step 1) is sealed and kept warm at room temperature for 4 days to obtain colorless transparent rod-shaped crystals, which are filtered and dried naturally to obtain a chiral ionic hydrogen-bonded organic framework material.

[0069] The yield of the hydrogen-bonded organic framework material obtained in this example is 65%.

[0070] Example 4

[0071] The invention discloses a method for preparing a low-temperature photochromic chiral ionic hydrogen-bonded organic framework material, comprising the following steps:

[0072] 1) dissolving H4TPE ligand and R / S-DPEN ligand in a mixed solution of water and methanol at a molar ratio of 1:2 to obtain a reaction solution; wherein the molar ratio of water to methanol is 1:2;

[0073] 2) The reaction solution obtained in step 1) is sealed and kept warm at room temperature for 5 days to obtain colorless transparent rod-shaped crystals, which are filtered and dried naturally to obtain a chiral ionic hydrogen-bonded organic framework material.

[0074] The yield of the chiral ionic hydrogen-bonded organic framework material obtained in this example is 70%.

[0075] In the above embodiments, Example 4 is taken as the best embodiment. The chiral ionic hydrogen-bonded organic framework material prepared in Example 4 is monochromatized by a graphite monochromator on a Brune smart APEXIICCD diffractometer. The ray was scanned in ω-θ mode at 298K, and the diffraction points were collected. The F2 was modified by full matrix least squares and the structural analysis was completed using SHELXL=2014 software package. The material belongs to the monoclinic system, the space group is P21, and the molecular formula is C 115 H 134 N8O 32 S8, unit cell parameters: α=90.00, β=90.3438(8), γ=90.00, The polymer is composed of multiple repeating units, each of which contains two H4TPE, four R / S-DPEN, one lattice water molecule and seven methanol molecules. The R / S-DPEN ligands are arranged alternately to form an organic ligand layer, and the H4TPE is embedded in the pores of the R / S-DPEN ligand layer. The adjacent sulfonic acid groups, amino groups, water molecules and methanol molecules are connected together by hydrogen bond interactions to form a three-dimensional (3D) supramolecular structure in a π-π stacking manner. Methanol molecules and water molecules connect R / S-DPEN and H4TPE to form a reticular hydrogen bond network.

[0076] like Figure 1-Figure 4As shown, the significant structural features of this material are: the asymmetric unit consists of two deprotonated TPE 4- Molecules, four R-DPEN 2+ In the structure of hydrogen bonded organic framework materials, TPE 4- Molecules and R-DPEN 2+ The molecules are connected by NH…O hydrogen bonds, and the solvent methanol molecules are connected to TPE 4- Molecule, R-DPEN 2+ The molecules are connected by OH…O and NH…O hydrogen bonds. At the same time, the solvent methanol molecules are also connected by OH…O hydrogen bonds. The solvent water molecules are also connected to the two TPE 4- molecule, an R-DPEN 2+ The molecules are connected by OH…O and NH…O hydrogen bonds, thus forming a continuous hydrogen bond network that extends infinitely along the a-axis, and there is a special "coplanar" hydrogen bond connection mode between the sulfonic acid group and the amino group. 2+ The molecules have the same structural hydrogen bonding pattern.

[0077] like Figure 5 As shown, by comparing the powder diffraction data of the obtained hydrogen-bonded organic framework material powder sample and the single crystal, it is found that the diffraction peaks of the obtained hydrogen-bonded organic framework material are consistent with the peaks simulated by the X-ray single crystal diffraction data, indicating that the purity of the obtained material powder sample is relatively high. It also proves that the experimental reproducibility of the sample is good.

[0078] like Figure 6 As shown, in order to simulate the harsh operating conditions in the real application environment, the present invention soaked the obtained hydrogen-bonded organic framework material in water for three days, dried it in a vacuum drying oven at 80°C for 5 hours to remove the solvent and grind it, and found that the crystalline structure changed, and then soaked it in methanol for 10 minutes and found that the structure recovered. The results show that the PXRD spectra before and after treatment are basically the same, indicating that the obtained hydrogen-bonded organic framework material has excellent stability and hydrogen bond reversibility.

[0079] like Figure 7 As shown, the thermal stability of the hydrogen-bonded organic framework material was obtained by thermogravimetric analysis. The thermogravimetric analysis curve shows that the three-dimensional structure of the hydrogen-bonded organic framework material can be stabilized to 280°C, after which it collapses. This shows that the prepared material has good thermal stability and is a new material with practical application value.

[0080] like Figure 8 As shown, the chiral ionic hydrogen-bonded organic framework material powder of the present invention exhibits a new absorption peak at 513 nm when irradiated with 365 nm ultraviolet light for 0 s to 30 s at -20°C.

[0081] like Fig. 9As shown, the chiral ionic hydrogen-bonded organic framework material of the present invention reversibly cycles between room temperature (25° C.) and low temperature (−20° C.) at 513 nm, indicating that photochromism is caused by temperature switching.

[0082] like Fig.10 As shown, the free radical signals of the chiral ionic hydrogen-bonded organic framework material of the present invention before and after 365nm ultraviolet irradiation at low temperature (-20°C) indicate that the photochromic mechanism at low temperature (-20°C) is affected by temperature-controlled photogenerated free radicals.

[0083] like Fig.11 As shown, the fluorescence spectra of the chiral ionic hydrogen-bonded organic framework material of the present invention at low temperature with the UV irradiation time (0s, 5s, 10s, 15s, 20s, 25s, 30s). The test results show that the fluorescence emission weakens with the extension of UV irradiation time at low temperature.

[0084] like Fig.12 As shown, the fluorescence lifetime of the chiral ionic hydrogen-bonded organic framework material of the present invention at 460 nm emission is 2.1636 ns, indicating that the chiral hydrogen-bonded organic framework material has good optical intrinsic emission.

[0085] like Fig.13 As shown, the circular dichroism (CD) spectrum of the chiral ionic hydrogen-bonded organic framework material of the present invention exhibits corresponding chiral signals on the left and right, indicating good chiral derivatization and amplification.

[0086] like Figure 14-15 As shown, the circularly polarized luminescence (CPL) spectrum and luminescence asymmetry factor (glum) of the chiral ionic hydrogen-bonded organic framework material of the present invention at room temperature (25° C.) indicate that it has good polarized light performance at room temperature.

[0087] like Figure 16-Figure 17 As shown, the circularly polarized luminescence (CPL) spectrum and luminescence asymmetry factor (glum) of the chiral ionic hydrogen-bonded organic framework material of the present invention at room temperature (-20°C) indicate that it has good polarized light performance at low temperatures.

[0088] like Fig.18 As shown, the color change photos of the chiral ionic hydrogen-bonded organic framework material of the present invention under 365nm ultraviolet light at room temperature (25°C), low temperature (0°C), and low temperature (-20°C).

[0089] In summary, the present invention synthesized a low-temperature photochromic CPL crystalline supramolecular chiral hydrogen-bonded organic framework. Its photochromism has a temperature-gating effect and a dual-mode switching color development mechanism under UV (365nm) excitation. Temperature-gating has a significant effect on the speed of color development, fading time and color development duration. When it is below -20°C, the UV-Vis spectrum absorption no longer continues to increase; and the color development is kept stable for a long time, and it will quickly restore the original color when placed above 0°C or even at room temperature.

[0090] In addition, chiral ionic hydrogen-bonded organic framework materials exhibit supramolecular chirality and have strong circular dichroism (CD) and circularly polarized luminescence (CPL) signals. Chiral ionic hydrogen-bonded organic framework materials have good circularly polarized luminescence (CPL) properties and a higher luminescence asymmetry factor in organic crystalline materials, with a glum value of ±1.7×10 -3 The chiral ionic hydrogen-bonded organic framework material has higher security in multiple response information encryption. The chiral ionic hydrogen-bonded organic framework material is a crystalline chiral material and can be used in multiple response information encryption, 3D smart display, photolithography printing and the like.

[0091] 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 above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A low-temperature photochromic chiral ionic hydrogen-bonded organic framework material, characterized in that: Its chemical formula is: [(H4TPE)2(R / S-DPEN)4·(CH3OH)7H2O] n , wherein n is a positive integer, H4TPE is tetrakis(4-phenylsulfonate)ethylene, and R / S-DPEN is R / S-diphenylethylenediamine.

2. The low-temperature photochromic chiral ionic hydrogen-bonded organic framework material according to claim 1, characterized in that: The structural unit of the chiral ionic hydrogen-bonded organic framework material belongs to the monoclinic system, the space group is P21, and the molecular formula is C 115 H 134 N8O 32 S8, unit cell parameters: α=90.00, β=90.3438(8), γ=90.00, 3. The low-temperature photochromic chiral ionic hydrogen-bonded organic framework material according to claim 1, characterized in that: The chiral ionic hydrogen-bonded organic framework material is polymerized by a plurality of repeating units, and each repeating unit contains two H4TPEs, four R / S-DPENs, one lattice water molecule and seven methanol molecules.

4. The low-temperature photochromic chiral ionic hydrogen-bonded organic framework material according to claim 3, characterized in that: The R / S-DPEN ligands are arranged alternately to form an organic ligand layer, and H4TPE is embedded in the pores of the R / S-DPEN ligand layer. The adjacent sulfonic acid groups, amino groups, water molecules, and methanol molecules are connected together by hydrogen bond interactions to form a three-dimensional (3D) supramolecular structure in a π-π stacking manner. Methanol molecules and water molecules connect R / S-DPEN and H4TPE to form a network of hydrogen bonds.

5. The low-temperature photochromic chiral ionic hydrogen-bonded organic framework material according to claim 1, characterized in that: The chiral ionic hydrogen-bonded organic framework material is a porous material with high structural stability, and can still maintain its original framework structure after being immersed in water for three days.

6. The low-temperature photochromic chiral ionic hydrogen-bonded organic framework material according to claim 1, characterized in that: The thermal stability decomposition temperature of the chiral ionic hydrogen-bonded organic framework material reaches 280°C.

7. The low-temperature photochromic chiral ionic hydrogen-bonded organic framework material according to claim 1, characterized in that: The chiral ionic hydrogen-bonded organic framework material has no photochromic phenomenon at room temperature and under 365nm ultraviolet light, and changes from a white solid powder to a red solid powder at -20°C and under 365nm ultraviolet light; The chiral ionic hydrogen-bonded organic framework material exhibits g lum = ±1.7 × 10 -3 The asymmetry factor of circularly polarized luminescence; g lum = ±3.1 × 10 -3 Asymmetry factor of circularly polarized luminescence.

8. The method for preparing the low-temperature photochromic chiral ionic hydrogen-bonded organic framework material according to any one of claims 1 to 7, characterized in that: The following steps are involved: 1) dissolving H4TPE ligand and R / S-DPEN ligand in a mixed solution of water and methanol at a molar ratio of 1:(1-4) to obtain a reaction solution; wherein the molar ratio of water to methanol is 1:(1-2); 2) The reaction solution obtained in step 1) is sealed and kept warm at room temperature for 3 to 5 days to obtain colorless transparent rod-shaped crystals, which are filtered and dried naturally to obtain a low-temperature photochromic chiral ionic hydrogen-bonded organic framework material.

9. The use of the chiral ionic hydrogen-bonded organic framework material according to any one of claims 1 to 7, characterized in that: Chiral ionic hydrogen-bonded organic framework materials are prepared into polymer matrix composite membranes, and the polymer matrix composite membranes are applied to multi-stimulus information encryption 、 3D smart display or photolithography printing.

10. The use of the chiral ionic hydrogen-bonded organic framework material according to claim 9, characterized in that: The specific steps of preparing the chiral ionic hydrogen-bonded organic framework material into a polymer matrix composite membrane are as follows: Dispersing the chiral ionic hydrogen-bonded organic framework material in water, mixing and stirring to obtain a suspension; The polyvinyl alcohol solution is added to the suspension, and the mixture is continuously stirred at room temperature to obtain a uniform solution; the mixed solution is applied to a silica glass substrate and dried to remove the solvent to obtain a polymer matrix composite film.

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