Thiophene-containing tetraarylethene compound as well as preparation method and application thereof

Abstract

The invention relates to the technical field of organic synthesis, and particularly provides a thiophene-containing tetraarylethene compound as well as a preparation method and application thereof. According to the invention, two phenyl groups of tetraphenylethylene are replaced by methyl formate thiophene groups, and the substituted tetraarylethylene compound has more remarkable photochromic and mechanochromic dual functions through the interaction of a specific substituent group at the position 2 of thiophene and a large conjugated group formed by four aromatic rings; and light-operated double-color display in a polymer mechanism can be realized. The mechanochromism of the compound does not depend on ultraviolet light, when the compound is subjected to mechanical force, the molecular accumulation mode and conjugate planarity are changed, and the color change can be directly observed by naked eyes. Different from traditional tetraphenyl ethylene force-induced discoloration recessive fluorescence change, the dominant color change can be used in the fields of visual stress monitoring, anti-counterfeiting marks, inkless writing materials, safe ink and the like in ultraviolet-free environments (such as indoor and closed spaces), and the application prospect is wide.

Description

Technical Field

[0001] This invention relates to the field of organic synthesis technology, and in particular to a thiophene tetraarylethylene compound, its preparation method, and its application. Background Technology

[0002] In the field of materials science, stimulus-responsive fluorescent materials, as a class of smart materials, have attracted much attention. Their color and fluorescence emission peak position / intensity can be switched or adjusted under the influence of external environmental stimuli such as heat, pressure, pH, light, water, ions, and small organic molecules. These materials are characterized by simple synthesis, fast response speed, and reproducible response, showing broad application prospects in many fields such as fluorescent sensors, memory chips, anti-counterfeiting paper, data storage, security inks, and bioimaging.

[0003] Among stimulus-responsive fluorescent materials, tetraphenylethylene (TPE) series molecules, due to their unique "crowded" structure, exhibit hindered intramolecular rotation, resulting in significant aggregation-induced emission. They possess superior performance, structural stability, and are easy to synthesize, leading to their widespread application in numerous fields. However, most tetraphenylethylene compounds currently exhibit only mechanochromic fluorescence. Mechanochromic fluorescence often relies on ultraviolet (UV) light irradiation; once removed from the UV environment, the color-changing effect becomes difficult to detect with the naked eye, significantly limiting their application in UV-deficient environments such as enclosed spaces and light-protected environments.

[0004] Currently, although some literature reports tetraphenylethylene compounds that exhibit both mechanochromic and photochromic effects, these effects still require ultraviolet light to be observed. In environments without ultraviolet light, the color-changing effect cannot be directly perceived by the naked eye. This makes it difficult to meet practical needs in applications that do not require ultraviolet light, such as stress visualization monitoring in daily environments and anti-counterfeiting labels without ultraviolet assistance, due to the lack of intuitive color change indicators that do not rely on ultraviolet light.

[0005] Therefore, developing a novel compound that overcomes the aforementioned defects of existing tetraphenylethylene compounds, achieves mechanochromic properties observable to the naked eye without ultraviolet irradiation, and simultaneously maintains photochromic properties, is of extremely important research significance and practical application value. Summary of the Invention

[0006] To address the limitations of existing mechanochromic or photochromic materials, such as limited functionality, the need for ultraviolet light assistance, and the difficulty in achieving visually perceptible mechanochromic changes without ultraviolet irradiation, this invention provides a thiophene-tetraarylethylene compound, its preparation method, and its applications. The thiophene-tetraarylethylene compound provided by this invention possesses both mechanochromic and photochromic properties, enabling visually observable mechanochromic changes even without ultraviolet irradiation, and thus has high application potential.

[0007] To solve the above-mentioned technical problems, the technical solution provided by the present invention is as follows:

[0008] A thiophene tetraarylethylene compound, the structural formula of which is shown in Formula I:

[0009]

[0010] Compared to existing technologies, this invention replaces the two phenyl groups of tetraphenylethylene with methyl formate-thiophene groups. Through the interaction of specific substituents at the 2-position with the large conjugated groups formed by the four aromatic rings, the substituted tetraphenylethylene compound exhibits both more significant photochromic and mechanochromic functions. This compound's mechanochromic effect does not rely on ultraviolet light; when subjected to mechanical force (grinding, stretching, etc.), the molecular packing and conjugated planarity change, and the color change is directly observable to the naked eye. Unlike the latent fluorescence change of traditional tetraphenylethylene mechanochromism, this explicit color change, even in environments without ultraviolet light (such as indoors or enclosed spaces), can be used for visual stress monitoring (such as material damage early warning), anti-counterfeiting labels (mechanical force triggers visible color change, enhancing anti-counterfeiting dimensions), inkless writing materials, and safety inks, with broad application prospects.

[0011] This invention also provides a method for preparing the above-mentioned thiophene tetraarylethylene compound, comprising the following steps:

[0012] S1, under an inert atmosphere and with catalyst a, diphenylacetylene undergoes an addition reaction with pinacol diboronic acid ester to obtain pinacol diboronic acid ester of formula II.

[0013]

[0014] S2, Under an inert atmosphere, with catalyst b and an acid-binding agent, the stilbene diboronic acid pinacol ester is coupled with methyl 4-halothiophene-2-carboxylate as shown in Formula III to obtain the thiophene tetraarylethylene compound shown in Formula I.

[0015]

[0016] Where R is Cl, Br, or I.

[0017] The method for preparing thiophene tetraarylethylene compounds provided by this invention requires only two reaction steps, has a short preparation route, simple process, high reaction conversion rate, high production safety, and is easy to realize large-scale production and application.

[0018] Further, in S1, the reaction solvent for the addition reaction is selected from at least one of N,N-dimethylformamide, dioxane, or acetonitrile.

[0019] A preferred reaction solvent can improve the yield and purity of the product obtained from the reaction of diphenylacetylene with pinacol diboronic acid ester.

[0020] Furthermore, in S1, the catalyst a is tetra(triphenylphosphine)platinum.

[0021] The preferred catalyst and dosage described above can promote the forward reaction of the addition reaction, increase the product yield, and reduce production costs.

[0022] Furthermore, the molar ratio of the diphenylacetylene to pinacol diboronic acid ester is 1:1 to 1:3.

[0023] In S1, the molar ratio of catalyst a to diphenylacetylene is 0.01:1 to 0.02:1.

[0024] In S1, the temperature of the addition reaction is 80℃~110℃, and the time of the addition reaction is 6h~9h.

[0025] It should be noted that in S1, after the addition reaction is completed, a post-processing procedure is also included: the solvent is removed by rotary evaporation of the reaction solution, and after cooling and solidification, dichloromethane is added to dissolve it, and then petroleum ether is added to recrystallize it to obtain stilbene diborate pinacol ester.

[0026] Specifically, in S1, the volume ratio of the petroleum ether to dichloromethane is 1:1.

[0027] Further, in S2, the reaction solvent for the coupling reaction is a mixed solution of an organic solvent and water, wherein the organic solvent is at least one of toluene, dioxane, or xylene.

[0028] Further, in S2, the catalyst b comprises an organopalladium catalyst and tetrabutylammonium bromide, wherein the organopalladium catalyst comprises at least one of tetra(triphenylphosphine)palladium, bis(triphenylphosphine)palladium dichloride, or 1,1'-bis(diphenylphosphine)ferrocenepalladium dichloride.

[0029] Furthermore, in S2, the acid-binding agent includes potassium carbonate, cesium carbonate, or sodium hydroxide.

[0030] Further, in S2, the molar ratio of stilbene diboronic acid pinacol ester, methyl 4-halothiophene-2-carboxylate, organopalladium catalyst, acid-binding agent and tetrabutylammonium bromide is 1:(2-2.4):(0.01-0.02):(1-4):(0.8-1.6).

[0031] Furthermore, in S2, the volume ratio of the organic solvent to water in the reaction solvent is 1.5:1 to 2.5:1.

[0032] Furthermore, in S2, the temperature of the coupling reaction is 80℃~100℃, and the time of the coupling reaction is 9h~15h.

[0033] It should be noted that in S2, after the coupling reaction is completed, a post-processing procedure is also included: after the reaction is completed, dichloromethane is added to the reaction solution for extraction, the extraction is repeated three times, the solvent is removed by rotary evaporation of the extract, and a mixed solvent of dichloromethane and anhydrous ethanol is added for recrystallization to obtain a compound containing thiophene tetraarylethylene.

[0034] Specifically, the volume ratio of dichloromethane to anhydrous ethanol is (1.5–2.5):1.

[0035] The method for preparing thiophene tetraarylethylene compounds provided by this invention is an atmospheric pressure reaction with a reaction temperature not exceeding 110°C. The reaction solvent does not require strict dehydration, and the conditions are mild. At the same time, the reaction route is short, the reaction raw materials are readily available, the reaction conversion rate is high, the economy is good, and it is easy to realize industrial production applications.

[0036] This invention also provides the application of the above-mentioned thiophene tetraarylethylene compounds in information storage materials, smart sensing materials, photosensitive materials, anti-counterfeiting materials, or smart detection materials.

[0037] The thiophene tetraarylethylene compound provided by this invention breaks through the limitations of traditional tetraphenylethylene stimulus response through structural innovation. With the dual effects of non-UV visible force-induced color change and flexible photochromism, it shows unique application value in fields such as anti-counterfeiting, sensing, and information storage, providing a new direction for the development of smart materials and achieving significant progress compared with existing materials.

[0038] The present invention also provides a mechanochromic material comprising the thiophene tetraarylethylene compound.

[0039] The present invention also provides a photochromic material comprising the thiophene tetraarylethylene compound.

[0040] The present invention also provides a material that combines mechanochromic and photochromic properties, including the thiophene tetraarylethylene compound.

[0041] The thiophene tetraarylethylene compound provided by this invention effectively expands the application scenarios of tetraphenylethylene compounds due to its unique photomechanical dual-response properties.

[0042] Traditional anti-counterfeiting relies on single photoluminescence / mechanical fluorescence, and mechanical fluorescence often requires ultraviolet (UV) assistance. This thiophene tetraarylethylene compound can be designed for dual-stimulus, dual-color-change anti-counterfeiting: in the absence of UV light, mechanical force triggers a visible color change; specific light exposure then reactivates the photoluminescence, constructing multi-level anti-counterfeiting measures and increasing the difficulty of counterfeiting. This is suitable for high-end luxury goods and document anti-counterfeiting. In flexible electronic devices, such as wearable stress sensors, mechanical color change can be identified visually without UV light, providing real-time feedback on stress distribution and deformation. In the field of information storage, based on the dual-stimulus response, force-light dual input signals can be encoded to achieve encrypted information storage. For example, mechanical color change writes primary information, and photoluminescence superimposes secondary information, significantly improving storage density and security.

[0043] Based on the material's structural characteristics, this thiophene-containing tetraarylethylene compound exists in a dual form within the polymer. Utilizing the spectral response differences of its dual forms, a two-color photochromic system can be easily constructed. This two-color system can achieve red and blue color-changing effects using different light sources. For example, ultraviolet light can change the material from colorless to blue, and red light can then change it to red. This two-color-changing mode does not require the use of multiple dyes; only one dye is needed for spontaneous color change, avoiding the complex process of compounding raw materials. At the information display level, it also eliminates the need for a micro-multicolor display unit design, as color changes can be achieved in a single location, increasing information density.

[0044] Furthermore, the thiophene tetraarylethylene compound provided by this invention can also be used as a smart detection material, including its application as a coating for damage detection in industrial equipment, and has significant application value in common and high-strength vulnerable components. Traditional detection methods suffer from difficulty in accurately locating wear points on such vulnerable components. Applying the photomechanical dual-response material coating of this invention to the surface of vulnerable components effectively solves this problem: when a part is damaged, the stress state on the coating surface changes, and without ultraviolet light irradiation, the coating exhibits a visible color change due to the force-induced color change effect; simultaneously, combined with its photochromic properties, under specific lighting conditions, the color difference can further enhance the identification signal of the damaged area. Based on this, during inspection, workers can quickly and accurately locate the wear area by directly observing the color change of the coating, significantly improving the efficiency and accuracy of damage detection in industrial equipment. Attached Figure Description

[0045] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0046] Figure 1 This is a color change diagram of the thiophene tetraarylethylene compound prepared in Example 1 of the present invention after ultraviolet light irradiation and grinding;

[0047] Figure 2 This is the UV-Vis absorption spectrum of the thiophene tetraarylethylene compound prepared in Example 1 of this invention before and after light irradiation;

[0048] Figure 3 This is the UV-Vis absorption spectrum of the thiophene tetraarylethylene compound prepared in Example 1 of this invention before and after grinding;

[0049] Figure 4 This is a color change diagram of the aldehyde-substituted thiophene tetraaryl ethylene compound prepared in Comparative Example 1 of the present invention after ultraviolet light irradiation and grinding.

[0050] Figure 5 This is a color change diagram of the thiophene tetraarylethylene compound prepared in Example 1 of the present invention exhibiting a bicolor photochromic effect under different light wavelengths. Detailed Implementation

[0051] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0052] Example 1

[0053] A thiophene tetraarylethylene compound has the following structural formula:

[0054]

[0055] The preparation method of the above-mentioned thiophene tetraarylethylene compound includes the following steps:

[0056] Step a: Weigh 5.054 g (0.02 mol) of pinacol diborate and 0.249 g (0.2 mmol) of tetrakis(triphenylphosphine)platinum, dissolve them in 50 mL of N,N-dimethylformamide, add them to a 250 mL three-necked flask, and purge with nitrogen to isolate oxygen. Then weigh 3.565 g (0.02 mol) of diphenylacetylene, dissolve it in 50 mL of N,N-dimethylformamide, and add it to the above flask. Heat to 110 °C and react for 6 h. After the reaction is complete, rotary evaporate the solvent, cool and solidify, add 20 mL of dichloromethane to dissolve it, add 20 mL of petroleum ether to recrystallize, filter, and obtain 7.76 g of white solid pinacol diborate compound, yield 89.8%.

[0057] Step b: Weigh 4.32 g (0.01 mol) of stilbene diboronic acid pinacol ester, 4.42 g (0.02 mol) of methyl 4-bromothiophene-2-carboxylate, 0.140 g (0.2 mmol) of bis(triphenylphosphine)palladium dichloride, 3.22 g (0.01 mol) of tetrabutylammonium bromide and 1.38 g (0.01 mol) of K2CO3 obtained in the previous step and add them to a three-necked flask. Then add 60 mL of toluene and 40 mL of deionized water to the three-necked flask, purge with nitrogen to prevent oxidation, heat in an oil bath to 90 °C, and react for 12 h. After the reaction is completed, add 50 mL of dichloromethane to extract the organic matter, repeat three times, evaporate the solvent by rotary evaporation, and recrystallize using 60 mL of a dichloromethane:anhydrous ethanol (2:1) mixed solvent to obtain 4.06 g of white solid powder, with a yield of 88%.

[0058] The product was characterized by nuclear magnetic resonance (NMR), and the spectral analysis data are as follows:

[0059] 1 H NMR (500MHz, CDCl3): δ7.41-7.39(m,2H), 7.14-7.06(m,8H), 7.01-6.97(s,4H), 3.83(s,6H).

[0060] FT-IR: 3083cm -1 2836cm -1 1714cm -1 1657cm -1 1530cm -1 1440cm -1 1266cm -1 1185cm -1 754cm -1 .

[0061] MS:C 26 H 20 O4S2, molecular weight: 460.08; measured value: 461.0874 [M+H].

[0062] Example 2

[0063] A thiophene tetraarylethylene compound has the following structural formula:

[0064]

[0065] The preparation method of the above-mentioned thiophene tetraarylethylene compound includes the following steps:

[0066] Step a: Weigh 10.108 g (0.04 mol) of pinacol diborate and 0.498 g (0.4 mmol) of tetra(triphenylphosphine)platinum, dissolve them in 50 mL of dioxane, add them to a 250 mL three-necked flask, and purge with nitrogen to isolate oxygen. Then weigh 3.565 g (0.02 mol) of diphenylacetylene, dissolve it in 50 mL of dioxane, and add it to the above flask. Heat to 90 °C and react for 8 h. After the reaction is complete, rotary evaporate the solvent, cool and solidify, add 20 mL of dichloromethane to dissolve it, then add 20 mL of petroleum ether to recrystallize, filter, and obtain 7.63 g of white solid pinacol diborate compound, yield 88.3%.

[0067] Step b: Weigh 4.32 g (0.01 mol) of stilbene diborate pinacol ester obtained in the previous step, 5.90 g (0.022 mol) of methyl 4-iodothiophene-2-carboxylate, 0.173 g (0.15 mmol) of tetratetraphenylphosphine palladium, 2.58 g (0.008 mol) of tetrabutylammonium bromide, and 6.52 g (0.02 mol) of Cs₂CO₃ and add them to a three-necked flask. Then add 80 mL of dioxane and 40 mL of deionized water to the three-necked flask, purge with nitrogen to prevent oxidation, heat in an oil bath to 100 °C, and react for 9 h. After the reaction is complete, add 50 mL of dichloromethane to extract the organic matter, and repeat three times. After rotary evaporation of the solvent, recrystallize using 60 mL of a dichloromethane:anhydrous ethanol (1.5:1) mixed solvent to obtain 3.688 g of white solid powder, yield 80%.

[0068] Example 3

[0069] A thiophene tetraarylethylene compound has the following structural formula:

[0070]

[0071] The preparation method of the above-mentioned thiophene tetraarylethylene compound includes the following steps:

[0072] Step a: Weigh 15.162 g (0.06 mol) of pinacol diborate and 0.373 g (0.3 mmol) of tetra(triphenylphosphine)platinum, dissolve them in 50 mL of acetonitrile, add them to a 250 mL three-necked flask, and purge with nitrogen to isolate oxygen. Then weigh 3.565 g (0.02 mol) of diphenylacetylene, dissolve it in 50 mL of acetonitrile, add it to the above flask, heat to 80 °C, and react for 9 h. After the reaction is complete, rotary evaporate the solvent, cool and solidify, add 20 mL of dichloromethane to dissolve it, add 20 mL of petroleum ether to recrystallize, filter, and obtain 7.56 g of white solid pinacol diborate compound, yield 87.5%.

[0073] Step b: Weigh 4.32 g (0.01 mol) of stilbene diboronic acid pinacol ester, 4.24 g (0.024 mol) of methyl 4-chlorothiophene-2-carboxylate, 0.146 g (0.2 mmol) of 1,1'-bis(diphenylphosphine)ferrocene palladium dichloride, 5.15 g (0.016 mol) of tetrabutylammonium bromide, and 1.6 g (0.04 mol) of NaOH into a three-necked flask. Then add 100 mL of xylene and 40 mL of deionized water to the three-necked flask, purge with nitrogen to prevent oxidation, heat in an oil bath to 80 °C, and react for 15 h. After the reaction is complete, add 50 mL of dichloromethane to extract the organic matter. Repeat three times. After rotary evaporation of the solvent, recrystallize using 60 mL of dichloromethane:anhydrous ethanol (2.5:1) to obtain 3.803 g of white solid powder, with a yield of 82.5%.

[0074] Experimental Example 1

[0075] Methoresistive and photochromic detection:

[0076] The solid powder containing thiophene tetraarylethylene compound prepared in Example 1 was irradiated with a 365nm ultraviolet lamp. The powder changed from white to blue. The blue powder was then ground, and the blue powder sample turned purplish-red after grinding.

[0077] This demonstrates that the thiophene tetraarylethylene compound prepared in the embodiments of the present invention has dual functions of photochromism and mechanochromism, and the mechanochromism can be observed with the naked eye without ultraviolet assistance, which is different from the traditional mechanochromism that relies on ultraviolet light, thus breaking through the application limitations of single stimulus-responsive materials.

[0078] Experimental Example 2

[0079] The ultraviolet absorption of the thiophene tetraarylethylene compound solid powder prepared in Example 1 was measured. The powder sample was irradiated with 365 nm ultraviolet light, and then tested using a UV-Vis spectrophotometer with an integrating sphere in diffuse reflectance mode. The UV-Vis absorption spectra before and after UV irradiation are shown below. Figure 2 As shown.

[0080] As shown in the figure, the sample did not absorb in the visible light band before ultraviolet light irradiation, but after ultraviolet light irradiation, an absorption peak appeared at 596 nm. The change in the absorption peak at 596 nm can be used as a clear indicator of light response.

[0081] Using an agate mortar, a thiophene tetraarylethylene compound that had been exposed to light was ground. The ultraviolet absorption spectra before and after grinding are as follows: Figure 3 As shown.

[0082] As can be seen from the figure, the absorption spectrum of the unground crystalline sample is between 550 nm and 650 nm, while the absorption spectrum of the ground amorphous sample shifts to between 480 nm and 550 nm, exhibiting obvious mechanochromic characteristics. This significant shift in the spectral range can serve as an intuitive mechanochromic signal.

[0083] The dual response of photochromism and mechanochromism, along with the corresponding spectral changes, constitute the performance advantages of this compound compared to traditional tetraphenylethylene compounds, providing core support for expanding its application scenarios.

[0084] Experimental Example 3

[0085] Two-color photochromic effect test

[0086] The specific testing method is as follows:

[0087] Dissolve 0.1g of polycaprolactone in 2mL of dichloromethane. After complete dissolution, add 0.007g of the thiophene tetraarylethylene compound prepared in Example 1 to the above solution. Pour the solution into a 2cm×2cm film mold to prepare a 7% polymer film.

[0088] like Figure 5 As shown, the polymer film appears white when not illuminated. When a rectangular mask is placed on the polymer film and irradiated with a 365nm UV lamp for 30 seconds, the polymer film will show a blue rectangle. Then, a heart-shaped mask is placed in the blue area and irradiated with a 650nm red lamp for 30 seconds. A red heart will appear in the blue rectangular area. At this time, the heart and rectangle on the polymer film form a high-contrast pattern.

[0089] This dual-color photochromic effect, which triggers blue and red color changes and forms high-contrast patterns using 365nm ultraviolet light and 650nm red light respectively, has clear and wide-ranging application value. It can be used for high-precision photocontrolled pattern fabrication. Leveraging the characteristic of different wavelengths triggering specific color changes, it eliminates the need for complex chemical etching or mechanical engraving. Simply by changing the mask and adjusting the light wavelength, multi-color, high-contrast patterns can be quickly drawn on polymer films, suitable for micro / nano pattern fabrication and electrode pattern marking in flexible electronic devices, simplifying the fabrication process while improving pattern accuracy. It also has advantages in information encryption and dynamic display. When unlit, the film is white with no obvious information traces. Irradiation with 365nm ultraviolet light allows blue "initial information" to be written, and then irradiation with 650nm red light superimposes red "secondary information" onto the blue area. Only by sequentially using specific wavelengths can multiple layers of information be fully read to enhance the encryption level. Furthermore, alternating between the two wavelengths allows for dynamic switching between blue and red patterns, suitable for dynamic content display in flexible displays and smart tags. It can also be applied to light-responsive anti-counterfeiting labels. Utilizing its high specificity—requiring specific wavelengths of light to trigger corresponding colors and exhibiting high pattern contrast that is easily identifiable to the naked eye—anti-counterfeiting labels can be created. Consumers or verifiers can quickly identify genuine products by observing whether a specific blue-red pattern appears when illuminated by a dedicated light source, thus increasing the difficulty of counterfeiting. This is suitable for anti-counterfeiting verification of high-end cosmetics, luxury goods, electronic components, and other products. Simultaneously, it has potential applications in the field of light-controlled sensors. By monitoring the color changes and contrast of the thin film under different wavelengths of light, parameters such as light wavelength and illumination time can be determined. Alternatively, it can serve as a response element in light intensity sensors; when the intensity of a specific wavelength of light reaches a threshold, the thin film displays the corresponding color, enabling visual monitoring of light signals. This is suitable for scenarios such as light environment monitoring and optical parameter calibration of optical equipment.

[0090] Comparative Example 1

[0091] This comparative example provides an aldehyde-substituted thiophene tetraaryl ethylene compound with the following structural formula:

[0092]

[0093] The preparation method of the above-mentioned aldehyde-substituted thiophene tetraaryl ethylene compound includes the following steps:

[0094] Step a: Weigh 12.635 g (0.05 mol) of pinacol diborate and 0.373 g (0.3 mmol) of tetra(triphenylphosphine)platinum, dissolve them in 50 mL of N,N-dimethylformamide, and then add them to a 250 mL three-necked flask. Purge with nitrogen gas. Then weigh 3.565 g (0.02 mol) of diphenylacetylene, dissolve it in 50 mL of N,N-dimethylformamide, and add it to the above flask. Heat to 90 °C and react for 6 h. After the reaction is complete, rotary evaporate the solvent, cool and solidify, add 20 mL of dichloromethane to dissolve it, then add 20 mL of petroleum ether to recrystallize. Filter to obtain 7.261 g of white solid pinacol diborate compound, yield 84%.

[0095] Step b: Weigh 4.32 g (0.01 mol) of stilbene diborate pinacol ester obtained in the previous step, 3.82 g (0.02 mol) of 4-bromothiophene-2-carboxaldehyde, 0.173 g (0.15 mmol) of tetrakis(triphenylphosphine)palladium, 3.22 g (0.01 mol) of tetrabutylammonium bromide and 1.38 g (0.01 mol) of K2CO3 and add them to a three-necked flask. Then add 80 mL of toluene and 40 mL of deionized water to the three-necked flask, purge with nitrogen, heat to 100 °C in an oil bath, and react for 12 h. After the reaction is complete, add 50 mL of dichloromethane to extract the organic matter. Repeat three times. After removing the solvent by rotary evaporation, recrystallize using 60 mL of a mixed solvent of dichloromethane and anhydrous ethanol (2:1) to obtain 3.32 g of light yellow solid powder, with a yield of 83%.

[0096] 1 H NMR (500MHz, CDCl3): δ7.02(m,4H),7.15(m,6H),7.32(s,2H),7.38(s,2H),9.76(s,2H). FT-IR(cm -1 ): 2988, 2900, 1669, 1393, 1231, 1066, 879, 662.

[0097] ESI: m / z test value: C 24 H 16 O2S2[M+H + ]: 401.0675; Theoretical value: 401.0664.

[0098] The aldehyde-substituted thiophene tetraarylethylene compound sample prepared above was irradiated with ultraviolet light at 365 nm for 1 minute, and the color changed from light yellow to green. Figure 4 As shown, this indicates that the material possesses photochromic properties. When the irradiated sample was ground again in a mortar, it remained green without any color change. Testing with a UV-Vis spectrophotometer also revealed no new absorption peaks, indicating that this sample lacks photochromic properties.

[0099] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions or improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A thiophene tetraarylethylene compound, characterized in that, Its structure is shown in Equation I:

2. A method for preparing the thiophene tetraarylethylene compound according to claim 1, characterized in that, Includes the following steps: S1, under an inert atmosphere and with catalyst a, diphenylacetylene undergoes an addition reaction with pinacol diboronic acid ester to obtain pinacol diboronic acid ester of formula II. S2, Under an inert atmosphere, with catalyst b and an acid-binding agent, the stilbene diboronic acid pinacol ester is coupled with methyl 4-halothiophene-2-carboxylate as shown in Formula III to obtain the thiophene tetraarylethylene compound shown in Formula I. Where R is Cl, Br, or I.

3. The method for preparing the thiophene tetraarylethylene compound as described in claim 2, characterized in that, In S1, the reaction solvent for the addition reaction is selected from at least one of N,N-dimethylformamide, dioxane, or acetonitrile; and / or In S1, catalyst a comprises tetra(triphenylphosphine)platinum.

4. The method for preparing the thiophene tetraarylethylene compound as described in claim 2 or 3, characterized in that, In S1, the molar ratio of diphenylacetylene to pinacol diboronic acid ester is 1:1 to 1:3; and / or In S1, the molar ratio of catalyst a to diphenylacetylene is 0.01:1 to 0.02:1; and / or In S1, the temperature of the addition reaction is 80℃~110℃, and the time of the addition reaction is 6h~9h.

5. The method for preparing the thiophene tetraarylethylene compound as described in claim 2, characterized in that, In S2, the reaction solvent for the coupling reaction is a mixed solution of an organic solvent and water, wherein the organic solvent is at least one selected from toluene, dioxane, or xylene; and / or In S2, catalyst b comprises an organopalladium catalyst and tetrabutylammonium bromide, wherein the organopalladium catalyst comprises at least one of tetra(triphenylphosphine)palladium, bis(triphenylphosphine)palladium dichloride, or 1,1'-bis(diphenylphosphine)ferrocene palladium dichloride; and / or In S2, the acid-binding agent includes potassium carbonate, cesium carbonate, or sodium hydroxide.

6. The method for preparing the thiophene tetraarylethylene compound as described in claim 5, characterized in that, In S2, the molar ratio of stilbene diborate pinacol ester, methyl 4-halothiophene-2-carboxylate, organopalladium catalyst, acid-binding agent, and tetrabutylammonium bromide is 1:(2-2.4):(0.01-0.02):(1-4):(0.8-1.6); and / or In S2, the volume ratio of organic solvent to water in the reaction solvent is 1.5:1 to 2.5:1; and / or In S2, the temperature of the coupling reaction is 80℃~100℃, and the time of the coupling reaction is 9h~15h.

7. The application of the thiophene tetraarylethylene compound of claim 1 in information storage materials, smart sensing materials, photosensitive materials, anti-counterfeiting materials, or smart detection materials.

8. A mechanochromic material, characterized in that, Including the thiophene tetraarylethylene compound as described in claim 1.

9. A photochromic material, characterized in that, Including the thiophene tetraarylethylene compound as described in claim 1.

10. A material possessing both mechanochromic and photochromic properties, characterized in that, Including the thiophene tetraarylethylene compound as described in claim 1.

Images