And Napos; 1, Napos; 3, the Napos is selected; application of 5-tri ((E)-4-(diphenylamino) benzylidene) benzene-1, 3, 5-tricarbohydrazide as piezo-chromic material

Abstract

The invention provides an application of N '1, N' 3, N '5-tri ((E)-4-(diphenylamino) benzylidene) benzene-1, 3, 5-tricarbohydrazide (TBTCH) as a piezo-chromic material. The invention provides a novel application of the compound TBTCH, and research shows that the compound has a polycrystalline state property and a piezochromic property, and has two single crystal structures TBTCH-c and TBTCH-g which emit cyan and green fluorescence under different wavelengths; under the action of pressure, the TBTCH-g is converted into an amorphous state from an original crystalline state and is converted into a yellow state sample, and the TBTCH-g can recover to the original state after being fumigated, so that the TBTCH-g has reversible piezochromism performance; and the TBTCH-c changes color under the action of pressure and cannot recover to the original state through a conventional fumigation method, but the TBTCH-g and the TBTCH-c can realize conversion between the TBTCH-g and the TBTCH-c through recrystallization. Therefore, the compound TBTCH can be used as a photochromic material to be applied to the fields of information encryption, intelligent display, biosensing, environmental monitoring and the like.

Description

Technical Field

[0001] This invention relates to the field of fluorescent materials technology, and more specifically, to the application of N'1,N'3,N'5-tris((E)-4-(diphenylamino)benzyl)phenyl-1,3,5-tricarbonylhydrazide as a pressure-sensitive color-changing material. Background Technology

[0002] Chromogenic materials are a class of smart materials that undergo reversible or irreversible color changes in response to external stimuli (such as light, heat, electricity, force, pH, etc.). In recent years, these materials have shown broad application prospects in fields such as information encryption, smart displays, biosensing, and environmental monitoring. Combining photochromic, thermochromic, and electrochromic materials (such as a tri-color viologen composite system) in information encryption and anti-counterfeiting can achieve multi-level information encryption. They can also be used to prepare reversible / irreversible indicators, such as polydiyne-based freezing indicators for monitoring temperature abuse in cold chain logistics.

[0003] Pressure-sensitive materials belong to the category of organic sensitive materials (smart materials). Their color changes occur due to pressure causing a balance between cis and trans isomerism in molecules. Essentially, pressure affects the microstructure; for example, it perturbs electronic energy levels, causing phase transitions and defects, and induces various molecular structural isomers, thereby altering the position and shape of the compound's electronic absorption spectrum. Currently, these materials are all high-molecular organic materials.

[0004] Existing mechanochromic materials suffer from insufficient sensitivity and irreversible color change. For example, most mechanochromic materials require high-intensity mechanical stress (e.g., >10 MPa) to develop color, making it difficult to detect minute deformations. Furthermore, materials such as carbazole derivatives often undergo irreversible structural damage after being subjected to stress, rendering them unsuitable for dynamic sensing. The core shortcomings of current mechanochromic compounds lie in their stability, reversibility, environmental adaptability, and cost. Currently, there is still a lack of small-molecule compounds suitable for preparing piezochromic materials. Summary of the Invention

[0005] The purpose of this invention is to provide the application of the organogel compound N'1,N'3,N'5-tris((E)-4-(diphenylamino)benzyl)phenyl-1,3,5-tricarbonylhydrazide as a pressure-sensitive color-changing material.

[0006] The above-mentioned objective of this invention is achieved through the following technical solution: This invention provides a novel application of N'1,N'3,N'5-tris((E)-4-(diphenylamino)benzylene)phenyl-1,3,5-tricarbonylhydrazine (TBTCH) as a pressure-sensitive fluorescent material. Previous work in this invention involved constructing a triphenylamine-benzene-1,3,5-tricarbonylhydrazine molecular gel exhibiting aggregation-induced emission (AIE) by introducing hydrazine hydrate and trimethylbenzene-1,3,5-tricarboxylic acid. Further studies revealed that this compound possesses multifunctional optical properties—polycrystalline properties and pressure-sensitive fluorescent properties. The compound TBTCH has two single-crystal structures: TBTCH-c emits cyan fluorescence at 477 nm, and TBTCH-g emits green fluorescence at 498 nm. Under pressure, TBTCH-g transforms from its crystalline state to an amorphous state, becoming a yellow sample. It can revert to its original morphology after fumigation, exhibiting reversible pressure-induced color change. TBTCH-c, however, changes color under pressure and cannot be restored to its original state by conventional fumigation methods. The conversion between TBTCH-g and TBTCH-c can be achieved through recrystallization. Therefore, compound TBTCH can be used as a color-changing material in fields such as information encryption, smart displays, biosensing, and environmental monitoring.

[0007] The structural formula of N'1,N'3,N'5-tris((E)-4-(diphenylamino)benzyl)phenyl-1,3,5-tricarbonylhydrazide provided by this invention is shown below:

[0008] Therefore, this invention provides the application of compounds with the above-described structural formulas as pressure-sensitive color-changing materials.

[0009] This invention provides the application of compounds with the above-described structure in the preparation of pressure-sensitive color-changing materials.

[0010] This invention provides the application of compounds with the above-described structures in information storage and anti-counterfeiting identification.

[0011] This invention provides the application of compounds with the above-described structures in the preparation of information storage and anti-counterfeiting identification products.

[0012] This invention provides the application of compounds with the above-described structures in information encryption and decryption.

[0013] Preferably, the encryption is achieved by pressurizing the compound; the decryption is achieved by steam fumigation of the compound.

[0014] This invention provides the application of compounds with the above-described structures in the preparation of rewritable optical media.

[0015] Preferably, the rewritable optical medium contains a single crystal structure TBTCH-g of N'1,N'3,N'5-tris((E)-4-(diphenylamino)benzyl)phenyl-1,3,5-tricarbonylhydrazide.

[0016] This invention provides the application of compounds with the above-described structures in the preparation of indicators.

[0017] This invention provides the application of compounds with the above-described structures in the preparation of colorimetric reagents.

[0018] The present invention has the following beneficial effects: This invention provides the application of N'1,N'3,N'5-tris((E)-4-(diphenylamino)benzylene)phenyl-1,3,5-tricarbonylhydrazine (TBTCH) as a pressure-sensitive color-changing material. This invention provides a new application for the compound TBTCH, which exhibits polycrystalline and pressure-sensitive properties. It has two single-crystal structures: TBTCH-c emits cyan fluorescence at 477 nm, and TBTCH-g emits green fluorescence at 498 nm. Under pressure, TBTCH-g transforms from its crystalline state to an amorphous state, becoming a yellow sample. After fumigation, it can revert to its original morphology, exhibiting reversible pressure-sensitive color-changing properties. TBTCH-c, however, changes color under pressure and cannot be restored to its original state by conventional fumigation methods. The conversion between TBTCH-g and TBTCH-c can be achieved through recrystallization. Therefore, the compound TBTCH can be used as a color-changing material in fields such as information encryption, smart display, biosensing, and environmental monitoring. Attached Figure Description

[0019] Figure 1 Fluorescence spectra of TBTCH-c and TBTCH-g (fluorescence images of TBTCH-c and TBTCH-g single crystals under 365 nm illumination).

[0020] Figure 2 The single-crystal structures of TBTCH-g(a) and TBTCH-c(b) containing DMSO molecules are shown, as well as the dihedral angles between the central benzene ring (a) and the peripheral benzene rings B, C, and D.

[0021] Figure 3 Fluorescence images of TBTCH solid samples under 365 nm illumination (a: (1) TBTCH-g, (2) ground TBTCH-g sample, (3) smoked TBTCH-g sample, (4) TBTCH-c, (5) ground TBTCH-c sample; b: a rewritable optical medium based on the surface of TBTCH-g, coated on filter paper after grinding (writing) and fumigation (wiping off); c: fluorescence spectrum of TBTCH-g; d: fluorescence spectrum of TBTCH-c).

[0022] Figure 4 XRD curves of TBTCH-g(a) and TBTCH-c(b) under different conditions.

[0023] Figure 5 SEM images of TBTCH (A: TBTCH-c; B: ground sample of TBTCH-c; C: TBTCH-g; D: ground sample of TBTCH-g). Detailed Implementation

[0024] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but the embodiments do not limit the present invention in any way. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in this technical field.

[0025] Unless otherwise specified, all reagents and materials used in the following examples are commercially available.

[0026] Trimethylbenzene-1,3,5-tricarboxylic acid, hydrazine hydrate, and 4-(diphenylamino)benzaldehyde were purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.

[0027] Example 1: Preparation of the compound The N'1,N'3,N'5-tris((E)-4-(diphenylamino)benzyl)benzene-1,3,5-tricarbonylhydrazide compound used in this embodiment was synthesized from 1,3,5-benzyltrihydrazide and 4-diphenylaminobenzaldehyde according to the method reported in the prior art (CN112125823A).

[0028] The specific method is as follows: In a 100 ml round-bottom flask, 25 mL of ethanol was added, followed by the addition of compound 2 (0.67 g, 2.66 mmol) to prepare solution 1. In another 100 ml round-bottom flask, 50 mL of DMSO was added, followed by the addition of 4-diphenylaminobenzaldehyde (2.6 g, 9.56 mmol) to prepare solution 2. After dissolution, solution 1 was added to solution 2, and then 2 drops of glacial acetic acid were added. The mixture was refluxed at 80 °C for 24 h. After the reaction was complete, the mixture was cooled to room temperature, filtered under reduced pressure, and the crude product was washed three times with ethanol and dried to obtain the pure target compound TBTCH as a yellow solid, with a yield of 71.6%.

[0029] Its synthetic route is as follows:

[0030] Example 2: Cultivation and determination of compound single crystals Weigh 10 mg of N'1,N'3,N'5-tris((E)-4-(diphenylamino)benzyl)phenyl-1,3,5-tricarbonylhydrazide (TBTCH), dissolve it in a good solvent, then add 10 mL of a poor solvent. Allow the solvent to evaporate naturally and observe whether clear crystals precipitate. Observe the morphology of the crystals using an inverted fluorescence microscope and perform X-ray crystallography analysis using a Bruker SMART II CCD area detector.

[0031] In the presence of multiple flexible hydrazide groups, TBTCH single crystals, TBTCH-c and TBTCH-g, can be successfully prepared by slow evaporation of mixtures of DMSO / chloroform / methanol (v / v / v = 1:5:5) and DMSO / THF (v / v = 1:2). Figure 1 As shown.

[0032] TBTCH-c emits cyan fluorescence at 477 nm with a fluorescence efficiency (ΦF) of 45.3%, while TBTCH-g emits green fluorescence at 498 nm with a ΦF value of 29.2%, as shown in Table 1. This result indicates that TBTCH exhibits polymorphism. Compared to TBTCH-g, TBTCH-c shows a higher ΦF value, which is due to the larger radiative rate constant of TBTCH-c. k f = 1.73×10 8 s -1 and a smaller nonradiative rate constant ( k nr = 2.09×10 8 s -1 ) compared to TBTCH-g ( k f = 1.64×10 8 s -1 , k nr =3.98×10 8 s -1 The compound TBTCH exhibits polycrystalline properties.

[0033] Table 1. Fluorescence wavelength, fluorescence quantum efficiency, and attenuation parameters of TBTCH under different solid-state conditions.

[0034] Further research and analysis were conducted on the molecular conformations of TBTCH-g and TBTCH-c, such as... Figure 2As shown, the molecular conformation of TBTCH-c is more distorted than that of TBTCH-g. The dihedral angles between the central benzene ring (A) and the peripheral benzene rings B, C, and D of TBTCH-g are 17.55°, 34.98°, and 35.95°, respectively, while those of TBTCH-c are 18.02°, 35.16°, and 36.05°, respectively. Although both TBTCH-g and TBTCH-c substrate samples are amorphous, they emit different fluorescence colors and have different quantum efficiencies.

[0035] Example 3 Detection of the piezochromic properties of compounds A certain amount of compound TBTCH was weighed and ground evenly in a mortar until the powder color completely changed. The powder was then collected for later use. The samples before and after grinding were examined using infrared spectroscopy to detect whether there were changes in the intermolecular chemical structure, fluorescence spectroscopy to detect whether there were changes in the emission wavelength of the molecules, and SEM and XRD to detect whether there were changes in the crystal form and morphology of the compound.

[0036] After grinding with a mortar and pestle, the green-emitting TBTCH-g showed a 30 nm redshift in its emission spectrum from 498 nm to 528 nm, transforming into a yellow sample. Its ΦF decreased from 29.2% to 15.5%, indicating that the compound possesses MFC properties. Figure 3 As shown in (1) and (2) of a. The X-ray powder diffraction (XRD) curves show that the crystal structure is destroyed after grinding, and the strong and sharp diffraction peaks completely disappear, as shown in (1) and (2). Figure 4 As shown. Furthermore, SEM images indicate that the large columnar crystals of TBTCH-g underwent significant damage during grinding, such as... Figure 5 As shown. Therefore, the change in solid-state fluorescence color is attributed to the transformation of the compound from a crystalline to an amorphous state. The sample fumigated with ethyl acetate (EA) vapor exhibited a 22 nm blue shift in its emission spectrum and emitted yellow-green fluorescence at λem = 506 nm, with a ΦF value of 27.3%. For the fumigated sample, only a few broad and weak diffraction peaks (θ = 5.41°, 11.51°, and 16.31°) reappeared, and the XRD curve could not be completely recovered from the original sample's diffraction curve, indicating it was likely a mixture of crystalline and amorphous states.

[0037] For TBTCH-c, the obtained sample, after grinding, emitted a yellow-green fluorescence at λem = 512 nm, with a ΦF value of 28.3%. Figure 3 As shown in (1) and (4) of a. However, the solid fluorescence color of the sample after grinding cannot be restored to its original state by conventional fumigation methods.

[0038] Although the fluorescence color and spectrum of the ground TBTCH-c sample were very similar to those of the smoked TBTCH-g sample, the XRD curve showed that the sample was completely amorphous. Heating the TBTCH-c sample at 217℃ for 1 h and then cooling it to room temperature resulted in an annealed sample consistent with the smoked TBTCH-g sample, as shown in the image. Figure 3 As shown in (1) and (3) of a. The conversion between TBTCH-g and TBTCH-c can only be achieved through recrystallization under appropriate conditions. Considering the reversible MFC activity of the TBTCH-g sample, it can be developed into a rewritable optical medium.

[0039] Example 4: Application of compound pressure-induced color change The TBTCH-g solid was placed on filter paper coated with commercially available solid adhesive, and then a hollowed-out animal pattern model was placed on the surface of the TBTCH-g. The hollow part was polished with a metal scraper and then irradiated at 365 nm.

[0040] The results are as follows Figure 3 As shown in b, due to the transformation from crystalline to amorphous state during grinding, the two polymorphs TBTCH-g and TBTCH-c exhibit good MFC activity. A yellow animal image appears against a green background, exhibiting high color contrast. This animal image disappears after being fumigated with EA vapor. Based on the reversible pressure-induced color change properties of the TBTCH-g surface, different color information can be achieved by grinding (writing) and fumigating (wiping) onto filter paper. TBTCH-g transforms from its original crystalline state to an amorphous state, resulting in a yellow sample, which can revert to its original state after fumigation; while TBTCH-c changes color under pressure and cannot be restored to its original state by conventional fumigation methods. However, the conversion between TBTCH-g and TBTCH-c can be achieved through recrystallization. Therefore, the compound TBTCH can be applied as a color-changing material in fields such as information encryption, smart displays, biosensing, and environmental monitoring.

[0041] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. Use of N'1, N'3, N'5-tris((E)-4-(diphenylamino)benzylidene)benzene-1, 3, 5-tricarbohydrazide as a pressure-induced color-changing material.

2. Use of N'1, N'3, N'5-tris((E)-4-(diphenylamino)benzylidene)benzene-1, 3, 5-tricarbohydrazide in the preparation of a pressure-induced color-changing material.

3. Use of N'1, N'3, N'5-tris((E)-4-(diphenylamino)benzylidene)benzene-1, 3, 5-tricarbohydrazide in information storage and anti-counterfeiting identification.

4. Use of N'1, N'3, N'5-tris((E)-4-(diphenylamino)benzylidene)benzene-1, 3, 5-tricarbohydrazide in the preparation of information storage and anti-counterfeiting identification products.

5. Use of N'1, N'3, N'5-tris((E)-4-(diphenylamino)benzylidene)benzene-1, 3, 5-tricarbohydrazide in information encryption and decryption.

6. Use according to claim 5, characterized in that, The encryption is achieved by pressing the compound to encrypt the information; the decryption is achieved by steam fumigation of the compound to decrypt the information.

7. Use of N'1, N'3, N'5-tris((E)-4-(diphenylamino)benzylidene)benzene-1, 3, 5-tricarbohydrazide in the preparation of rewritable optical media.

8. Use of N'1, N'3, N'5-tris((E)-4-(diphenylamino)benzylidene)benzene-1, 3, 5-tricarbohydrazide in the preparation of an indicator.

9. Use of N'1, N'3, N'5-tris((E)-4-(diphenylamino)benzylidene)benzene-1, 3, 5-tricarbohydrazide in the preparation of a color developing agent.

10. The use according to any one of claims 1 to 9, characterized in that, The structure of the N'1, N'3, N'5-tris((E)-4-(diphenylamino)benzylidene)benzene-1, 3, 5-tricarbohydrazide is as follows: 。

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