Luminescent material based on conjugated modified dithienyl anthracene-phenanthroimidazole skeleton as well as preparation method and application of luminescent material

Abstract

The invention belongs to the technical field of organic photoelectric functional materials, and particularly relates to a luminescent material based on a conjugated modified dithienyl anthracene-phenanthroimidazole skeleton and a preparation method and application thereof. According to the invention, substituent groups (phenyl, naphthyl, anthryl, pyrenyl and triphenylamine) with different conjugation degrees are selectively introduced, and the system regulates the steric hindrance and electronic structure of molecules, so that collaborative optimization of mechanical stimuli response and aggregation-induced emission is successfully realized; the molecular engineering strategy can accurately control the force-induced discoloration behavior (blue-green-yellow reversible transformation) and AIE characteristics of the material, and keeps excellent biocompatibility at the same time. The method disclosed by the invention not only discloses a regulation and control rule of substituent conjugation degree and spatial configuration on material performance, but also provides a designable molecular platform for developing a novel intelligent luminescent material, and has important application value in the fields of anti-counterfeiting encryption, biological imaging, flexible photoelectricity and the like.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of organic photoelectric functional materials, and particularly relates to a luminescent material based on a conjugation-modified dithiophene-based anthracene-phenanthroimidazole skeleton and a preparation method and application thereof. BACKGROUND

[0002] As a core research direction in the field of intelligent response materials, organic photoelectric functional materials have important value in the development of molecular devices and intelligent systems. Traditional light-responsive materials generally exhibit fluorescence quenching (ACQ) effect in the aggregated state, which seriously limits their practical applications. Aggregation-induced emission (AIE) successfully solves this problem through a unique intramolecular restricted internal motion (RIM) mechanism. This theoretical system adopts a non-planar helical molecular design, effectively inhibits fluorescence quenching caused by π-π stacking, and realizes efficient luminescence in the aggregated state. The excellent luminescent properties of AIE materials in the solid state make them have unique advantages in emerging fields such as flexible display and intelligent anti-counterfeiting, and provide a new way for the development of the next generation of functional materials.

[0003] At present, existing schemes use the intramolecular restricted internal motion (RIM) mechanism to effectively inhibit π-π stacking and realize efficient luminescence in the aggregated state by designing non-planar molecular structures (such as helical, star-shaped molecules) or introducing AIE units such as tetraphenyl ethylene. On this basis, in order to endow the material with a mechanochromic (MFC) function, researchers have developed various strategies, for example, constructing a non-covalent interaction network to induce reversible conversion of the molecular stacking mode by external force; designing molecules with multiple stable crystal forms to realize the conversion between crystal and amorphous states by mechanical force; introducing flexible alkyl chains to drive the reorganization of luminophores through their deformation. For anthracene-based materials, the classic scheme is to introduce large steric aryl groups (such as DSA derivatives) at the 9,10 position.

[0004] In the past decade, mechanically responsive luminescent materials based on changes in molecular packing structure have become a research hotspot due to their unique stimulus response characteristics. Under the action of mechanical force stimulation (such as extrusion, grinding or shearing), these materials can realize precise regulation of luminescent color through reversible conversion of the molecular packing mode, and have important application value in the fields of fluorescent switches, high-density information storage and stress sensing. However, traditional mechanochromic materials are generally limited by the aggregation-induced fluorescence quenching (ACQ) effect, resulting in a significant decrease in solid-state luminescent efficiency. This key scientific problem has prompted researchers to work on the development of new aggregation-induced efficient luminescent materials. Notably, the emergence of aggregation-induced emission (AIE) materials provides an innovative approach to solving this problem, realizing the synergistic regulation of mechanical force response and efficient luminescence through rational molecular design, and opening up a new way for the development of high-performance intelligent luminescent materials.

[0005] Anthracene-based fluorescent materials have become the core system of organic optoelectronic functional materials due to their excellent optical properties, high thermal stability and strong designability, and have important application value in the fields of OLED devices, fluorescent probes, transistors and photovoltaic cells. However, traditional anthracene-based materials generally face the problem of aggregation-induced fluorescence quenching (ACQ). SUMMARY

[0006] In order to solve the above technical problems, the present application provides a luminescent material based on a conjugated modified dithiophene-based anthracene-phenanthroimidazole skeleton, a preparation method and application thereof. By adjusting the conjugation degree and steric hindrance effect of the terminal substituent, the synergistic optimization of high contrast force-induced color change and aggregation-induced emission is realized, which provides theoretical guidance and molecular design concept for the development of new functional stimulus-responsive materials.

[0007] To achieve the above object, the technical scheme adopted by the present application is: The first aspect of the present application provides a luminescent material based on a conjugated modified dithiophene-based anthracene-phenanthroimidazole skeleton, which has the following general structure: ; In the formula, R is selected from any one of phenyl, naphthyl, anthryl, pyrenyl and triphenylamine.

[0008] Further, the luminescent material is any one of the following compounds: .

[0009] The second aspect of the present application provides a preparation method of a luminescent material based on a conjugated modified dithiophene-based anthracene-phenanthroimidazole skeleton, comprising the following steps: The 5-(10-(thiophen-2-yl)anthracen-9-yl)thiophene-2-carboxaldehyde (active aldehyde intermediate), phenanthrenequinone, p-bromoaniline and ammonium acetate are subjected to condensation reaction in an organic solvent to obtain 1-(4-bromophenyl)-2-(5-(10-(thiophen-2-yl)anthracen-9-yl)thiophen-2-yl)-1H-phenanthro[9,10-d]imidazole, denoted as DTAPI-Br; the source of 5-(10-(thiophen-2-yl)anthracen-9-yl)thiophene-2-carboxaldehyde is as follows: Effects of substituents on the optical properties of AIEE-active 9,10-dithiopheneanthrylene derivatives and their applications in cell imaging, authors: Jie Zhang, Renjie Wang, Duohua Jiang, Shouzhi Pu, year: 2021.

[0010] The 1-(4-bromophenyl)-2-(5-(10-(thiophen-2-yl)anthracen-9-yl)thiophen-2-yl)-1H-phenanthro[9,10-d]imidazole, conjugated boronic acid compound, palladium catalyst and basic compound are subjected to coupling reaction in an organic solvent under a protective atmosphere to obtain a luminescent material based on a conjugated modified dithiophene-based anthracene-phenanthroimidazole skeleton.

[0011] Further, the molar ratio of 5-(10-(thiophen-2-yl)anthracen-9-yl)thiophene-2-carboxaldehyde, phenanthrenequinone, p-bromoaniline and ammonium acetate is 1:1:1:4-8.

[0012] Further, the temperature of the condensation reaction is 110-120°C and the time is 3-4h; the temperature of the coupling reaction is 80-85°C and the time is 7-10h.

[0013] Further, the conjugated boronic acid compound is selected from any one of benzene boronic acid, 1-naphthalene boronic acid, 9-anthracene boronic acid, 1-pyrene boronic acid and 4-(diphenylamino)benzene boronic acid.

[0014] Further, the palladium catalyst is tetrakis(triphenylphosphine)palladium (Pd(PPh3)4).

[0015] Further, the basic compound is sodium carbonate (Na2CO3).

[0016] Further, the molar ratio of 1-(4-bromophenyl)-2-(5-(10-(thiophen-2-yl)anthracen-9-yl)thiophen-2-yl)-1H-phenanthro[9,10-d]imidazole and the conjugated boric acid compound is 1:1.5, the amount of the palladium catalyst is 1 mol% to 5 mol% of the total amount of 1-(4-bromophenyl)-2-(5-(10-(thiophen-2-yl)anthracen-9-yl)thiophen-2-yl)-1H-phenanthro[9,10-d]imidazole (DTAPI-Br) and the conjugated boric acid compound, and the molar ratio of 1-(4-bromophenyl)-2-(5-(10-(thiophen-2-yl)anthracen-9-yl)thiophen-2-yl)-1H-phenanthro[9,10-d]imidazole and the basic compound is 1:1 to 1.5.

[0017] The present application aims to solve the core problem of traditional organic luminescent materials in the aggregation state due to the close packing leading to fluorescence quenching (i.e. ACQ effect), and the technical bottlenecks such as low contrast, uncontrollable color change behavior and molecular design strategy of existing mechanochromic materials. Through a molecular design strategy based on substitution site engineering, the present application focuses on how to realize the dual goals of aggregation-induced emission (AIE) and high-contrast reversible mechanochromic performance through molecular structure regulation. Specifically, the purpose is to explore the structure-activity relationship between the conjugation degree, spatial configuration (coplanar and non-coplanar) and steric hindrance effect of the substituent group and the photophysical properties of the material, so as to establish a new strategy that can effectively regulate the luminescent color and mechanical response performance, and provide a theoretical basis and feasible design scheme for developing new multifunctional organic luminescent materials with excellent AIE characteristics, high-contrast mechanochromic ability and good biocompatibility, to meet the high-performance application requirements in the fields of optical information storage, biological imaging and intelligent optoelectronic devices.

[0018] The present application provides the application of the luminescent material based on the conjugated modified dithiophene-based anthracene-phenanthroimidazole skeleton in the third aspect of the present application in mechanochromic sensing, cell fluorescence imaging, security ink or anti-counterfeiting identification.

[0019] The application adopts a molecular engineering and systematic substituent configuration regulation strategy based on a 9,10-dithienyl anthracene imidazole rigid skeleton. The scheme is no longer limited to single molecule modification, but by introducing substituents with different conjugation properties and spatial configurations (coplanar and non-coplanar) on the same parent nucleus, five derivatives are constructed, so as to realize the synergistic enhancement of AIE characteristics and high-contrast reversible mechanochromism (blue-green-yellow), and reveal the regulation mechanism of bulky coplanar and non-coplanar groups on AIE and mechanochromic behavior. In addition, the application further successfully applies the luminescent material to live cell imaging, proves the excellent biocompatibility, realizes the complete closed loop from molecular design, mechanism research to biological application, provides a new strategy for molecular engineering of customizable multifunctional optical physical behavior, and solves the problem of existing schemes focusing on single performance optimization or lacking of systematic structure-activity relationship and biological application verification.

[0020] Compared with the prior art, the application has the following beneficial effects: 1. Through molecular structure design, the conjugation degree and steric hindrance effect of the terminal substituent are regulated, the synergistic optimization of high-contrast mechanochromism and aggregation-induced emission is realized, the aggregation-induced emission (AIE) characteristics and mechanochromic properties are efficiently integrated, and a theoretical guidance and molecular design concept are provided for developing a new type of functional stimulus response material.

[0021] 2. Through precise substituent site engineering regulation, the regulatable design of the spectral response of the mechanochromic material is realized, the luminescent color can change significantly with mechanical force stimulation, and has excellent reversibility, and can meet the diversified application requirements of intelligent sensing, dynamic display and the like.

[0022] 3. The luminescent material based on the conjugation modified dithienyl anthracene-phenanthroimidazole skeleton as the mechanochromic material exhibits good biocompatibility, which provides a possibility for developing a new type of biological mechanics sensing and live cell mechanics imaging technology.

[0023] 4. The luminescent material based on the conjugation modified dithienyl anthracene-phenanthroimidazole skeleton provides a new generation of multifunctional material platform with force response characteristics for intelligent optoelectronic devices (such as optical memory), multi-level anti-counterfeiting systems and biological diagnosis and treatment instruments.

[0024] 5、The application successfully develops a new material system with aggregation-induced emission (AIE) and high-contrast mechanochromic dual-function characteristics, and through molecular engineering strategy regulation, the DTAPI series compounds present strong fluorescence emission in solid state, realize high-contrast and reversible mechanochromic response from blue-green to yellow, have low cytotoxicity and excellent biocompatibility, and have been successfully applied to live cell imaging. The application has the advantages that the functional limitations of traditional materials are broken through, the controllable regulation of optical performance is realized through substitution group engineering, a new strategy is provided for intelligent material design, the AIE characteristics and the mechanochromic property are efficiently integrated, and the aggregation state fluorescence quenching problem is solved. Overall, the application provides a multifunctional material platform with excellent performance for high-end anti-counterfeiting encryption, optical information storage and biomechanical sensing fields. BRIEF DESCRIPTION OF DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor on the basis of these drawings.

[0026] Figure 1 The fluorescence lifetime changes of the compounds DTAPI-Ph, DTAPI-Na, DTAPI-An, DTAPI-Py and DTAPI-TPA obtained in Example 2 to Example 6 under different environments, and the excitation wavelength is 390 nm. Among them, (A) is the fluorescence lifetime of the compound DTAPI-Ph in pure THF, THF solution with 80% water content and solid state; (B) is the fluorescence lifetime of the compound DTAPI-Na in pure THF, THF solution with 80% water content and solid state; (C) is the fluorescence lifetime of the compound DTAPI-An in pure THF, THF solution with 80% water content and solid state; (D) is the fluorescence lifetime of the compound DTAPI-Py in pure THF, THF solution with 80% water content and solid state; (E) is the fluorescence lifetime of the compound DTAPI-TPA in pure THF, THF solution with 80% water content and solid state.

[0027] Figure 2The comparison of solid-state and liquid fluorescence emission spectra of compounds DTAPI-Ph, DTAPI-Na, DTAPI-An, DTAPI-Py, and DTAPI-TPA obtained in Examples 2 to 6 is shown. Among them, (A) is the liquid fluorescence emission spectrum of compounds DTAPI-Ph, DTAPI-Na, DTAPI-An, DTAPI-Py, and DTAPI-TPA; (B) is the solid-state fluorescence emission spectrum of compounds DTAPI-Ph, DTAPI-Na, DTAPI-An, DTAPI-Py, and DTAPI-TPA.

[0028] Figure 3 The images show the water content ratio fluorescence spectra and fluorescence photographs of the compounds DTAPI-Ph, DTAPI-Na, DTAPI-An, DTAPI-Py, and DTAPI-TPA obtained in Examples 2 to 6. In the images, (A) is the fluorescence spectrum of DTAPI-Ph, (B) is the fluorescence spectrum of DTAPI-Na, (C) is the fluorescence spectrum of DTAPI-An, (D) is the fluorescence spectrum of DTAPI-Py, (E) is the fluorescence spectrum of DTAPI-TPA, and (F) is a fluorescence photograph of the DTAPI derivatives in different solutions under 365 nm ultraviolet light irradiation. 0%–90% represent different water content ratios (volume percentage) in the mixed solutions.

[0029] Figure 4 The following are particle size distributions of compounds DTAPI-Ph, DTAPI-Na, DTAPI-An, DTAPI-Py, and DTAPI-TPA obtained in Examples 2 to 6 when aggregated in a solution with a THF:H2O volume ratio of 2:8: (A) shows the particle size distribution of compound DTAPI-Ph when aggregated in a solution with a THF:H2O volume ratio of 2:8, indicating that the average particle size in the aggregated state is 301 nm; (B) shows the particle size distribution of compound DTAPI-Na when aggregated in a solution with a THF:H2O volume ratio of 2:8. (C) is a particle size diagram of compound DTAPI-An aggregated in a solution with a THF:H2O volume ratio of 2:8, showing an average particle size of 367 nm; (D) is a particle size diagram of compound DTAPI-Py aggregated in a solution with a THF:H2O volume ratio of 2:8, showing an average particle size of 401 nm; (E) is a particle size diagram of compound DTAPI-TPA aggregated in a solution with a THF:H2O volume ratio of 2:8.

[0030] Figure 5The images shown are scanning electron microscope (SEM) images of compounds DTAPI-Ph, DTAPI-Na, DTAPI-An, DTAPI-Py, and DTAPI-TPA obtained in Examples 2 to 6 in their aggregated state. Specifically, (A) is an SEM image of compound DTAPI-Ph at 500 nm, (B) is an SEM image of compound DTAPI-Ph at 300 nm, (C) is an SEM image of compound DTAPI-Na at 500 nm, (D) is an SEM image of compound DTAPI-Na at 300 nm, (E) is an SEM image of compound DTAPI-An at 500 nm, (F) is an SEM image of compound DTAPI-An at 300 nm, (G) is an SEM image of compound DTAPI-Py at 500 nm, (H) is an SEM image of compound DTAPI-Py at 300 nm, and (I) is an SEM image of compound DTAPI-TPA at 500 nm. Scanning electron microscope (SEM) images at 300 nm, and (J) is a scanning electron microscope image of compound DTAPI-TPA at 300 nm.

[0031] Figure 6 The images show the mechanically ground fluorescence emission spectra and images under 365 nm UV light irradiation of compounds DTAPI-Ph, DTAPI-Na, DTAPI-An, DTAPI-Py, and DTAPI-TPA obtained in Examples 2 to 6. Specifically, (A) is the fluorescence emission spectrum of DTAPI-Ph, (B) is the fluorescence emission spectrum of DTAPI-Na, (C) is the fluorescence emission spectrum of DTAPI-An, (D) is the fluorescence emission spectrum of DTAPI-Py, (E) is the fluorescence emission spectrum of DTAPI-TPA, and (F) is an image of DTAPI-Ph, DTAPI-Na, DTAPI-An, DTAPI-Py, and DTAPI-TPA under 365 nm UV light irradiation.

[0032] Figure 7 The images show the X-ray diffraction patterns of compounds DTAPI-Ph, DTAPI-Na, DTAPI-An, DTAPI-Py, and DTAPI-TPA obtained in Examples 2 to 6 before and after grinding; (A) to (E) are the X-ray diffraction patterns of compounds DTAPI-Ph, DTAPI-Na, DTAPI-An, DTAPI-Py, and DTAPI-TPA, respectively.

[0033] Figure 8The bar charts show the cytotoxicity of compounds DTAPI-Ph, DTAPI-Na, DTAPI-An, DTAPI-Py, and DTAPI-TPA obtained in Examples 2 to 6 over 24 hours. (A) is a bar chart of the cytotoxicity of compound DTAPI-Ph over 24 hours; (B) is a bar chart of the cytotoxicity of compound DTAPI-Na over 24 hours; (C) is a bar chart of the cytotoxicity of compound DTAPI-An over 24 hours; (D) is a bar chart of the cytotoxicity of compound DTAPI-Py over 24 hours; and (E) is a bar chart of the cytotoxicity of compound DTAPI-TPA over 24 hours.

[0034] Figure 9 The images show the cytotoxicity bar charts of compound DTAPI-Ph obtained in Examples 2-6 over 24 hours, and its fluorescence imaging in cells. Specifically, A1-C1 are bright-field, dark-field, and superimposed images of the blank control; A2-C2 are fluorescence imaging images of compound DTAPI-Ph in cells; A3-C3 are fluorescence imaging images of compound DTAPI-Na in cells; A4-C4 are fluorescence imaging images of compound DTAPI-An in cells; A5-C5 are fluorescence imaging images of compound DTAPI-Py in cells; and A6-C6 are fluorescence imaging images of compound DTAPI-TPA in cells.

[0035] Figure 10 This describes the synthetic route for luminescent materials based on a conjugated modified dithienylanthracene-phenanthrimidazole framework. Detailed Implementation

[0036] The specific embodiments of the present invention are described in detail below, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0037] 9,10-Diarylanthracene (DSA) derivatives have become a research hotspot in this field due to their unique intramolecular restricted motion (RIM) mechanism and significant AIE effect. DSA system derivatives have been successfully applied in fields such as bioimaging and protein labeling. However, current research on anthracene-based AIE materials mainly focuses on the DSA structure, while research on other structural types of anthracene-based AIE materials is relatively scarce. It is worth noting that phenanthreneimidazole, as a fluorophore with a rigid, large-planar conjugated structure, has gained widespread application in the field of fluorescent dyes due to its unique molecular structure, which can significantly improve fluorescence efficiency. This material not only possesses advantages such as simple synthesis, low cost, good solubility, and excellent processing performance, but also exhibits excellent thermal stability, electron transport capabilities, and outstanding photoluminescence / electroluminescence properties, showing great potential in the research of high-efficiency luminescent materials.

[0038] Based on the advantages of the 9,10-dihexaanthracene derivatives synthesized in previous work, such as good AIE properties, unique mechanical fluorescence color-changing (MFC) properties, excellent biocompatibility and high luminescence efficiency, this invention aims to develop a novel luminescent material with both ideal AIE properties and high-contrast color mechanical fluorescence properties, with 9,10-dithienylanthiazole as the core, providing new ideas for expanding the structural diversity of anthracene-based AIE materials.

[0039] This invention provides a method for preparing luminescent materials based on a conjugated modified dithienylanthracene-phenanthreneimidazole framework. The first step is the Debus–Radziszewski imidazole synthesis, a chemical reaction that prepares imidazole derivatives from diketones, aldehydes, and ammonia. This reaction involves the dehydration condensation of the diketone with ammonia to generate a diimine intermediate, which then forms the imidazole ring structure.

[0040] The second step is the Suzuki coupling reaction, also known as the Suzuki reaction. Under the catalysis of zero-valent palladium complexes, aryl or alkenylboronic acids or boronic esters undergo cross-coupling with chlorinated, bromine, or iodoaryl hydrocarbons or alkenes. The haloaryl hydrocarbon undergoes oxidative addition with Pd(0), forming an organopalladium hydroxide intermediate with a base. This intermediate replaces the weakly polar palladium halogen bond, and the strongly polar Pd-OH intermediate exhibits strong electrophilicity. Simultaneously, the base reacts with arylboronic acid to form a tetravalent borate intermediate, which is highly electronegative and facilitates migration to the Pd metal center. The synergistic effect of these two aspects forms the organopalladium complex Ar-Pd-Ar', which undergoes reduction and elimination to generate the aryl-coupled product. The process parameters are the optimal parameters obtained through numerous experiments. Too high a parameter will result in incomplete reaction, wasting raw materials and reagents; too low a parameter may lead to a low yield. During preparation, attention must be paid to the reaction time and temperature; insufficient reaction time will result in a low yield. During processing, the number of extractions must be considered; too few extractions may waste materials. During purification, pay attention to the eluent used; insufficient purification may affect the accuracy of the test. The specific steps are as follows:

[0041] Step (1): The active aldehyde intermediate is mixed with phenanthrenequinone, p-bromoaniline, ammonium acetate and organic solvent to carry out a condensation reaction to obtain an intermediate 1-(4-bromophenyl)-2-(5-(10-(thiophene-2-yl)anthracene-9-yl)thiophene-2-yl)-1H-phenanthrene[9,10-d]imidazolium containing p-bromobenzene on the imidazolium ring, denoted as DTAPI-Br.

[0042] In step (1), the molar ratio of the active aldehyde intermediate to phenanthrenequinone, p-bromoaniline, and ammonium acetate is 1:1:1:4-8; the amount of acetic acid solvent used is 20 mL-50 mL; the temperature of the condensation reaction is 110℃-120℃, and the time is 3 h-4 h; the organic solvent is glacial acetic acid. After the condensation reaction is completed, the present invention preferably performs post-treatment on the reaction solution, which preferably includes the following steps: adding ice water to the condensation reaction solution for quenching to obtain a solid product; washing and filtering the solid with pure water multiple times to remove residual acetic acid solvent from the product; washing and filtering the obtained solid product with methanol / ethanol solvent multiple times to obtain the green solid product DTAPI-Br.

[0043] Step (2): Under a protective atmosphere, DTAPI-Br is mixed with a conjugated boric acid compound, a palladium catalyst, a basic compound and an organic solvent to carry out a Suzuki coupling reaction to obtain a luminescent material based on a conjugated modified dithienylanthracene-phenanthrimidazole framework.

[0044] In step (2), the conjugated boric acid compound is selected from phenylboronic acid, 1-naphthoboronic acid, 9-anthraboronic acid, 1-pyreneboronic acid, and 4-(diphenylamino)phenylboronic acid; the molar ratio of DTAPI-Br to the conjugated boric acid compound is 1:1.2 to 1.5; the molar percentage of palladium catalyst in the total amount of DTAPI-Br and conjugated boric acid compound is 1 mol% to 5 mol%; the amount of organic solvent is 80 mL to 250 mL; the basic compound is added in solid form, and the molar ratio of DTAPI-Br to the basic compound is 1:1 to 1.5; the temperature of the Suzuki coupling reaction is 80℃ to 85℃, the time is 7 h to 10 h, and the protective atmosphere is argon; the palladium catalyst is Pd(PPh3)4; and the organic solvent is tetrahydrofuran. After the Suzuki coupling reaction is completed, the present invention preferably performs post-treatment on the reaction solution, which preferably includes the following steps: cooling the Suzuki coupling reaction solution to room temperature and removing the solvent by rotary evaporation to obtain the rotary evaporation residue; repeatedly extracting with dichloromethane and water, combining the organic phases, washing with saturated sodium chloride solution and water, drying with anhydrous sodium sulfate for 2 hours, and then purifying by silica gel column chromatography. In the present invention, the extractant used for extraction is preferably dichloromethane; the drying agent used for drying is preferably anhydrous sodium sulfate; the eluent used for column chromatography separation is preferably a mixture of petroleum ether and dichloromethane; the volume ratio of petroleum ether to dichloromethane in the mixture is preferably 1:2; the present invention does not have special requirements for the specific methods of rotary evaporation and filtration, and methods well known to those skilled in the art can be used. In the present invention, the DTAPI-Ph, DTAPI-Na, DTAPI-An, DTAPI-Py, and DTAPI-TPA obtained after column chromatography separation are all yellow-green solids.

[0045] Synthetic routes for luminescent materials based on conjugated modified dithienylanthracene-phenanthrimidazole frameworks are as follows: Figure 10 Wherein, R is selected from R1, R2, R3, R4, and R5; when R1 is phenyl, the luminescent material is denoted as DTAP-Ph; when R2 is naphthyl, the luminescent material is denoted as DTAP-Na; when R3 is naphthyl, the luminescent material is denoted as DTAP-An; when R4 is pyrene, the luminescent material is denoted as DTAP-Py; and when R5 is triphenylamino, the luminescent material is denoted as DTAP-TPA.

[0046] This invention synthesizes a series of compounds, DTAPI-Ph, DTAPI-Na, DTAPI-An, DTAPI-Py, and DTAPI-TPA, with dual functionalities of aggregation-induced emission (AIE) and mechanochromatic properties through precise molecular design. By introducing different electron-donating groups such as phenyl, naphthyl, anthracene, pyrene, and triphenylamine, the intermolecular interaction forces are effectively modulated, enabling the materials to exhibit strong fluorescence emission in the solid state while possessing excellent biolabeling capabilities. Of particular note is that the unique twisted molecular configuration and close-packed crystal structure of these compounds endow them with significant mechanochromatic response characteristics, exhibiting reversible fluorescence color changes in response to external stimuli. This intelligent responsiveness makes them promising for applications in high-end anti-counterfeiting encryption, optical information storage, mechanical sensing, and biomolecular mechanical imaging, providing an important reference for the development of next-generation multifunctional stimulus-responsive materials.

[0047] This invention, through the selective introduction of substituents with varying degrees of conjugation (phenyl, naphthyl, anthraceneyl, pyrene, and triphenylamine), systematically modulates the steric hindrance and electronic structure of molecules, successfully achieving synergistic optimization of mechanostimulation response and aggregation-induced emission (AIE). Research shows that this molecular engineering strategy can precisely control the mechanochromic behavior (reversible blue-green-yellow transition) and AIE properties of materials while maintaining excellent biocompatibility. This work not only reveals the regulatory mechanisms of substituent conjugation degree and spatial configuration on material properties but also provides a designable molecular platform for developing novel intelligent luminescent materials, with significant application value in fields such as anti-counterfeiting encryption, bioimaging, and flexible optoelectronics.

[0048] The five compounds provided in this invention—DTAPI-Ph, DTAPI-Na, DTAPI-An, DTAPI-Py, and DTAPI-TPA—exhibit significant structure-dependent photophysical properties. In tetrahydrofuran (THF) solution, the five compounds exhibit similar maximum emission wavelengths. Under solid-state conditions, the introduction of rigid planar groups significantly enhances intermolecular π-π stacking interactions, causing a redshift in the maximum emission wavelength. In contrast, the highly twisted triphenylamine unit, due to the disruption of molecular planarity and effective conjugation, exhibits a blueshift in the emission spectrum. The study found that these five compounds with highly twisted molecular structures exhibit significant mechanostimulation response characteristics under external stimuli, and their optical properties undergo a substantial wavelength redshift. This unique mechanochromatic effect originates from the significant changes in the intramolecular twisted conformation under external force, leading to molecular orbital energy level rearrangement and a decrease in electronic transition energy. This series of compounds demonstrates advantages such as rapid response, high sensitivity, and good reversibility. They have significant application value in fields such as intelligent sensing, optical information storage, and anti-counterfeiting encryption. These findings provide important evidence for the precise control of the photophysical properties of materials through molecular structure design, particularly guiding the development of mechanochromic materials with specific wavelength responses. This invention is the first to propose and apply for protection of a structural reconstruction strategy based on a dithienylanthracene-phenanthrimidazole framework, focusing on the innovative preparation method that uses engineering to modify the substituents of the dithienylanthracene-phenanthrimidazole ring to control the optical properties of materials. The scope of protection of this invention covers novel functional materials developed using this method and their innovative applications in high-end anti-counterfeiting encryption, optical information storage, mechanical sensing, and biomechanical imaging. This technology breaks through the limitations of traditional materials with single functions, providing original molecular design strategies and preparation processes for the development of next-generation intelligent responsive materials.

[0049] This invention employs a two-step synthetic strategy involving the Debus-Radziszewski reaction and the Suzuki coupling reaction. Compared to traditional methods, this approach offers advantages such as readily available raw materials and low cost, making it suitable for large-scale production. The route is simple and efficient, with mild reaction conditions and high yields, significantly improving synthetic efficiency. Furthermore, the Suzuki coupling allows for flexible control of the product structure, enabling diverse functionalities. The resulting products exhibit stable properties and strong modifiability, showing broad application prospects in optoelectronic materials and biomedicine.

[0050] Unless otherwise specified, the experimental methods described in the following embodiments of the present invention are conventional methods, and the materials and reagents used in the following embodiments are commercially available unless otherwise specified.

[0051] Example 1 Preparation of DTAPI-Br: 1.35 mmol of phenanthrenequinone, 1.35 mmol of 5-(10-(thiophene-2-yl)anthracene-9-yl)thiophene-2-carboxaldehyde, 1.35 mmol of p-bromoaniline, and 5.4 mmol of ammonium acetate were added to a 50 mL single-necked flask. 20 mL of glacial acetic acid was added and stirred to dissolve the precipitate. The mixture was refluxed in an oil bath at 120 °C for 4 h. After the reaction was complete, the mixture was cooled to room temperature, and the reaction solution was quenched in 100 mL of ice water. The precipitate was collected by suction filtration, washed repeatedly with pure water to remove residual acetic acid solvent, and then washed repeatedly with methanol / ethanol solvent. The product was dried under vacuum to obtain the intermediate 1-(4-bromophenyl)-2-(5-(10-(thiophene-2-yl)anthracene-9-yl)thiophene-2-yl)-1H-phenanthro[9,10-d]imidazole. The intermediate was a green solid with a yield of 70.6%, named DTAPI-Br. The reaction route is as follows:

[0052] .

[0053] Example 2 A method for preparing a luminescent material based on a conjugated modified dithienylanthracene-phenanthrimidazole framework is as follows: Under argon protection, 1-(4-bromophenyl)-2-(5-(10-(thiophene-2-yl)anthracene-9-yl)thiophene-2-yl)-1H-phenanthro[9,10-d]imidazole (DTAPI-Br, 0.7 mmol), tetra(triphenylphosphine)palladium (0.035 mmol), sodium carbonate (1.05 mmol), and phenylboronic acid (1.05 mmol) were dissolved in tetrahydrofuran (100 mL) and refluxed at 85 °C for 10 hours in a three-necked flask. After the reaction was complete, the mixture was cooled to room temperature, and the tetrahydrofuran was removed by rotary evaporation under reduced pressure. The mixture was repeatedly extracted with dichloromethane and water, and the combined organic phases were washed with saturated sodium chloride solution and water, and dried over anhydrous sodium sulfate for 2 hours. Purified by silica gel column chromatography (petroleum ether / dichloromethane, v / v = 1:2), a yellow-green solid DTAPI-Ph was obtained in 50.2% yield. This luminescent material, based on a conjugated modified dithienylanthracene-phenanthrimidazole framework, was named DTAPI-Ph. The reaction route is as follows:

[0054] .

[0055] Example 3 A method for preparing a luminescent material based on a conjugated modified dithienylanthracene-phenanthrimidazole framework is as follows: Under argon protection, DTAPI-Br (0.7 mmol), tetrakis(triphenylphosphine)palladium (0.035 mmol), sodium carbonate aqueous solution (1.05 mmol), and 1-naphthoboric acid (1.0 mmol) were dissolved in tetrahydrofuran (100 mL) and refluxed at 85 °C for 10 hours in a three-necked flask. After the reaction was complete, the mixture was cooled to room temperature, the solvent was removed by vacuum distillation, and the mixture was extracted with dichloromethane and water. The organic phase was washed with saturated sodium chloride solution and dried over anhydrous sodium sulfate. Purification was achieved by silica gel column chromatography (petroleum ether / dichloromethane, v / v = 1:2) to obtain a yellow-green solid DTAPI-Na (yield 42%), which is the luminescent material based on the conjugated modified dithienylanthracene-phenanthrimidazole framework, named DTAPI-Na. The reaction route is as follows:

[0056] Example 4 A method for preparing a luminescent material based on a conjugated modified dithienylanthracene-phenanthrimidazole framework is as follows: Under argon protection, DTAPI-Br (0.7 mmol), tetrakis(triphenylphosphine)palladium (0.020 mmol), sodium carbonate aqueous solution (1.05 mmol), and 1-anthrabenic acid (1.0 mmol) were dissolved in tetrahydrofuran (100 mL) and refluxed at 85 °C for 10 hours in a three-necked flask. After the reaction was complete, the mixture was cooled to room temperature, the solvent was removed by vacuum distillation, and the mixture was extracted with dichloromethane and water. The organic phase was washed with saturated sodium chloride solution and dried over anhydrous sodium sulfate. Purification was achieved by silica gel column chromatography (petroleum ether / dichloromethane, v / v = 1:2) to obtain the yellow-green solid DTAPI-An (yield 40.6%), which is the luminescent material based on the conjugated modified dithienylanthracene-phenanthrimidazole framework, named DTAPI-An. The reaction route is as follows:

[0057] .

[0058] Example 5 A method for preparing a luminescent material based on a conjugated modified dithienylanthracene-phenanthrimidazole framework is as follows: Under argon protection, DTAPI-Br (0.7 mmol), tetrakis(triphenylphosphine)palladium (0.035 mmol), sodium carbonate aqueous solution (1.05 mmol), and 1-pyreneboronic acid (1.0 mmol) were dissolved in tetrahydrofuran (100 mL) and refluxed at 85 °C for 10 hours in a three-necked flask. After the reaction was complete, the mixture was cooled to room temperature, the solvent was removed by vacuum distillation, and the mixture was extracted with dichloromethane and water. The organic phase was washed with saturated sodium chloride solution and dried over anhydrous sodium sulfate. Purification was performed by silica gel column chromatography (petroleum ether / dichloromethane, v / v = 1:2) to obtain the yellow-green solid DTAPI-Py (yield 44%), which is the luminescent material based on the conjugated modified dithienylanthracene-phenanthrimidazole framework, named DTAPI-Py. The reaction route is as follows:

[0059] .

[0060] Example 6 A method for preparing a luminescent material based on a conjugated modified dithienylanthracene-phenanthrimidazole framework is as follows: Under argon protection, DTAPI-Br (0.7 mmol), tetra(triphenylphosphine)palladium (0.035 mmol), sodium carbonate aqueous solution (1.05 mmol), and 4-(diphenylamino)phenylboronic acid (1.0 mmol) were dissolved in tetrahydrofuran (100 mL) and refluxed at 85 °C for 10 hours in a three-necked flask. After the reaction was complete, the mixture was cooled to room temperature, the solvent was removed by vacuum distillation, and the mixture was extracted with dichloromethane and water. The organic phase was washed with saturated sodium chloride solution and dried over anhydrous sodium sulfate. Purification was achieved by silica gel column chromatography (petroleum ether / dichloromethane, v / v = 1:2) to obtain the yellow-green solid DTAPI-TPA (yield 78.6%), which is a luminescent material based on a conjugated modified dithienylanthracene-phenanthrimidazole framework, named DTAPI-TPA. The reaction route is as follows:

[0061] .

[0062] Performance testing Figure 1The fluorescence lifetime changes of compounds DTAPI-Ph, DTAPI-Na, DTAPI-An, DTAPI-Py, and DTAPI-TPA obtained in Examples 2 to 6 under different environments were shown, with an excitation wavelength of 390 nm. Specifically, (A) represents the fluorescence lifetime of compound DTAPI-Ph in pure THF, THF solution with 80% water content, and in the solid state; (B) represents the fluorescence lifetime of compound DTAPI-Na in pure THF, THF solution with 80% water content, and in the solid state; (C) represents the fluorescence lifetime of compound DTAPI-An in pure THF, THF solution with 80% water content, and in the solid state; (D) represents the fluorescence lifetime of compound DTAPI-Py in pure THF, THF solution with 80% water content, and in the solid state; and (E) represents the fluorescence lifetime of compound DTAPI-TPA in pure THF, THF solution with 80% water content, and in the solid state. Figure 1 In pure THF solution, the fluorescence lifetimes of the five molecules were 1.25 ns, 1.72 ns, 2.62 ns, 2.32 ns, and 1.82 ns, respectively. When the water content of the THF solution increased to 80%, the fluorescence lifetimes became 1.93 ns, 1.92 ns, 2.36 ns, 1.64 ns, and 1.81 ns, respectively. Under solid-state conditions, the fluorescence lifetimes of the three molecules were 2.21 ns, 2.19 ns, 0.87 ns, 2.17 ns, and 1.77 ns, respectively.

[0063] Figure 2 The comparison shows the solid-state and liquid-state fluorescence emission spectra of compounds DTAPI-Ph, DTAPI-Na, DTAPI-An, DTAPI-Py, and DTAPI-TPA obtained in Examples 2 to 6; wherein, (A) is the liquid-state fluorescence emission spectrum of compounds DTAPI-Ph, DTAPI-Na, DTAPI-An, DTAPI-Py, and DTAPI-TPA; and (B) is the solid-state fluorescence emission spectrum of compounds DTAPI-Ph, DTAPI-Na, DTAPI-An, DTAPI-Py, and DTAPI-TPA. Figure 2 As can be seen from (A), the five DTAPI derivatives all exhibit similar fluorescence emission spectra in THF solution. Figure 2As shown in (B), DTAPI-An and DTAPI-Py exhibit long emission wavelengths, which can be attributed to the extended π-conjugated system formed by the rigid planar anthracene and pyrene structures. DTAPI-Ph and DTAPI-Na, containing phenyl and naphthyl substituents, exhibit medium emission wavelengths, while DTAPI-TPA exhibits the shortest emission wavelength due to the interruption of the π-conjugated system caused by the highly distorted conformation of its triphenylamine unit. These systematic spectral changes clearly demonstrate that introducing rigid planar groups to extend the π-conjugated system leads to a redshift, while highly distorted groups induce a blueshift by disrupting the conjugated system. This comparative analysis lays the foundation for controlling photophysical properties through molecular design; by controlling the degree of conjugation and molecular geometry, luminescence behavior can be effectively modulated.

[0064] Figure 3 The images show the water content ratio fluorescence spectra and fluorescence photographs of the compounds DTAPI-Ph, DTAPI-Na, DTAPI-An, DTAPI-Py, and DTAPI-TPA obtained in Examples 2 to 6. In the images, (A) is the fluorescence spectrum of DTAPI-Ph, (B) is the fluorescence spectrum of DTAPI-Na, (C) is the fluorescence spectrum of DTAPI-An, (D) is the fluorescence spectrum of DTAPI-Py, (E) is the fluorescence spectrum of DTAPI-TPA, and (F) is a fluorescence photograph of the DTAPI derivatives in different solutions under 365 nm ultraviolet light irradiation. 0%–90% represent different water content ratios (volume percentage) in the mixed solutions. Figure 3 It can be seen that DTAPI-Ph (2.0×10) -5 The fluorescence intensity of DTAPI-Na (mol / L) in dilute solutions with good solvent (THF) as the main component is weak; when the water content increases to 90%, the molecules aggregate to form nanoparticles, and their fluorescence intensity increases by 2 to 3 times compared to the non-aggregated state. DTAPI-Na, DTAPI-An, DTAPI-Py, and DTAPI-TPA also aggregate when the water content reaches 80%, and the fluorescence intensity increases by 2 to 3 times. All three exhibit significant aggregation-induced emission (AIE) characteristics, confirming the AIE activity of the compounds prepared in this invention.

[0065] Figure 4The following are particle size distributions of compounds DTAPI-Ph, DTAPI-Na, DTAPI-An, DTAPI-Py, and DTAPI-TPA obtained in Examples 2 to 6 when aggregated in a solution with a THF:H2O volume ratio of 2:8: (A) shows the particle size distribution of compound DTAPI-Ph when aggregated in a solution with a THF:H2O volume ratio of 2:8, indicating that the average particle size in the aggregated state is 301 nm; (B) shows the particle size distribution of compound DTAPI-Na when aggregated in a solution with a THF:H2O volume ratio of 2:8. (A) is a particle size distribution diagram of compound DTAPI-An aggregated in a solution with a THF:H2O volume ratio of 2:8, showing an average particle size of 367 nm; (B) is a particle size distribution diagram of compound DTAPI-Py aggregated in a solution with a THF:H2O volume ratio of 2:8, showing an average particle size of 401 nm; (C) is a particle size distribution diagram of compound DTAPI-An aggregated in a solution with a THF:H2O volume ratio of 2:8, showing an average particle size of 280 nm; (D) is a particle size distribution diagram of compound DTAPI-Py aggregated in a solution with a THF:H2O volume ratio of 2:8, showing an average particle size of 401 nm; (E) is a particle size distribution diagram of compound DTAPI-TPA aggregated in a solution with a THF:H2O volume ratio of 2:8. Figure 4 It can be seen that the average particle size in the aggregated state is 182 nm.

[0066] Figure 5 The images shown are scanning electron microscope (SEM) images of compounds DTAPI-Ph, DTAPI-Na, DTAPI-An, DTAPI-Py, and DTAPI-TPA obtained in Examples 2 to 6 in their aggregated state. Specifically, (A) is an SEM image of compound DTAPI-Ph at 500 nm, (B) is an SEM image of compound DTAPI-Ph at 300 nm, (C) is an SEM image of compound DTAPI-Na at 500 nm, (D) is an SEM image of compound DTAPI-Na at 300 nm, (E) is an SEM image of compound DTAPI-An at 500 nm, (F) is an SEM image of compound DTAPI-An at 300 nm, (G) is an SEM image of compound DTAPI-Py at 500 nm, (H) is an SEM image of compound DTAPI-Py at 300 nm, and (I) is an SEM image of compound DTAPI-TPA at 500 nm. Scanning electron microscope (SEM) images at 300 nm, (J) is a scanning electron microscope image of compound DTAPI-TPA at 300 nm. From Figure 5 As shown in the figure, the morphological characteristics of the polymerized DTAPI derivatives were investigated using SEM experiments. Five compounds self-assembled into beaded nanoparticles in a mixed solution with a water ratio of 80% THF / H2O, exhibiting significant aggregation-induced emission (AIE) behavior. This confirms that these DTAPI derivatives form a tightly packed molecular structure during self-assembly.

[0067] Figure 6 The images show the mechanically ground fluorescence emission spectra and images under 365 nm UV light irradiation of compounds DTAPI-Ph, DTAPI-Na, DTAPI-An, DTAPI-Py, and DTAPI-TPA obtained in Examples 2 to 6. (A) is the fluorescence emission spectrum of DTAPI-Ph, (B) is the fluorescence emission spectrum of DTAPI-Na, (C) is the fluorescence emission spectrum of DTAPI-An, (D) is the fluorescence emission spectrum of DTAPI-Py, (E) is the fluorescence emission spectrum of DTAPI-TPA, and (F) is an image of DTAPI-Ph, DTAPI-Na, DTAPI-An, DTAPI-Py, and DTAPI-TPA under 365 nm UV light irradiation. The mechanical grinding procedure was as follows: the sample was placed in an agate mortar and ground continuously in the same direction with an agate pestle for 5 to 10 minutes until a significant change in the substance was observed under UV light irradiation. The dichloromethane fumigation procedure was as follows: An agate mortar containing the ground sample was placed in a glass petri dish filled with dichloromethane, covered, and fumigated for 15 minutes. The sample was then observed under ultraviolet light to see if it had recovered its original color. Fluorescence spectroscopy analysis showed that after mechanical grinding, DTAPI-Ph, DTAPI-Na, DTAPI-An, DTAPI-Py, and DTAPI-TPA exhibited redshifts of 50 nm, 35 nm, 29 nm, 38 nm, and 48 nm, respectively, and the emission color changed from blue-green to bright yellow. This color change was visually demonstrated in ultraviolet light photographs. Notably, after 15 minutes of dichloromethane fumigation, the emission spectra and emission colors of all five compounds recovered to their initial states, confirming their excellent optical reversibility. This result fully demonstrates that this series of compounds possesses significant mechanochromic fluorescence (MFC) characteristics.

[0068] Figure 7 X-ray diffraction patterns of compounds DTAPI-Ph, DTAPI-Na, DTAPI-An, DTAPI-Py, and DTAPI-TPA obtained in Examples 2 to 6 before and after grinding; (A) to (E) are the X-ray diffraction patterns of compounds DTAPI-Ph, DTAPI-Na, DTAPI-An, DTAPI-Py, and DTAPI-TPA, respectively. The original powder samples all exhibited sharp and intense diffraction peaks, confirming their highly ordered crystal structure. After mechanical grinding, the characteristic diffraction peaks significantly weakened, indicating that the crystal structure had transformed into an amorphous phase. After annealing with dichloromethane vapor, the sharp diffraction peaks reappeared, confirming that the crystal order was completely restored. This series of changes clearly demonstrates that all five compounds possess excellent reversible mechanical force response.

[0069] The specific procedure for the cytotoxicity assay is as follows: After counting A549 cells, they were seeded into 96-well plates and cultured in an incubator for 24 hours. Then, the original culture medium was discarded, and 10 µL of the test solution containing 10–30 µM DTAPI derivative was added to each well, followed by another 24 hours of culture. Afterward, the liquid in the wells was aspirated, and diluted MTT solution (dilution ratio of MTT to culture medium: 1:10, initial MTT concentration: 5 mg / ml) was added. The plates were incubated for 4 hours, and the absorbance of each well was measured using a microplate reader (wavelength of absorbance: 390 nm–750 nm). Cytotoxicity was then calculated based on this absorbance.

[0070] Figure 8 The bar charts show the cytotoxicity of compounds DTAPI-Ph, DTAPI-Na, DTAPI-An, DTAPI-Py, and DTAPI-TPA obtained in Examples 2 to 6 over 24 hours. (A) is a bar chart of the cytotoxicity of compound DTAPI-Ph over 24 hours; (B) is a bar chart of the cytotoxicity of compound DTAPI-Na over 24 hours; (C) is a bar chart of the cytotoxicity of compound DTAPI-An over 24 hours; (D) is a bar chart of the cytotoxicity of compound DTAPI-Py over 24 hours; and (E) is a bar chart of the cytotoxicity of compound DTAPI-TPA over 24 hours. Figure 8 As can be seen, A549 cells treated with 10-30 μM DTAPI derivatives for 24 hours still exhibited metabolic activity exceeding 85% at a concentration of 10 μM, indicating low cytotoxicity at this working concentration.

[0071] Figure 9The images show the cytotoxicity bar graphs of compound DTAPI-Ph obtained in Examples 2-6 (A) over 24 hours, and fluorescence imaging in cells. A1-C1 are bright-field, dark-field, and superimposed images of the blank control; A2-C2 are fluorescence imaging images of compound DTAPI-Ph in cells; A3-C3 are fluorescence imaging images of compound DTAPI-Na in cells; A4-C4 are fluorescence imaging images of compound DTAPI-An in cells; A5-C5 are fluorescence imaging images of compound DTAPI-Py in cells; and A6-C6 are fluorescence imaging images of compound DTAPI-TPA in cells. Group A is a bright-field image, Group B is a dark-field image, and Group C is a superimposed image of dark-field and bright-field images. "Blank" refers to pure cells without any added substances in the three fields. Cell imaging experiment procedure: A549 cells were cultured in DMEM medium containing 10% fetal bovine serum at 37°C and 5% CO2, and seeded overnight in 20mm culture dishes. After washing with PBS, the samples were stained with DTAPI-Ph, DTAPI-Na, DTAPI-An, DTAPI-Py, and DTAPI-TPA for 30 minutes each, respectively. After washing three times with PBS, imaging was performed using an OLYMPUS FV1000 confocal microscope in the 490-590 nm emission channel. Figure 9 As shown, A1-C1 are the dark field, bright field, and superimposed images of the blank control; A2-C2, A3-C3, A4-C4, A5-C5, and A6-C6 are the corresponding imaging results of the five compounds. The experimental results demonstrate that these compounds can effectively enter A549 cells and exhibit excellent staining effects, confirming their potential application as novel cellular fluorescent markers.

[0072] This invention develops a high-performance mechanochromic and aggregation-induced emission (AIE) material design strategy based on precise modification of the dithienyl anthracene-phenanthrimidazole skeleton. By selectively introducing substituents with different degrees of conjugation (phenyl, naphthyl, anthracene, pyrene, triphenylamine), the steric hindrance and electronic structure of the molecule are systematically controlled, successfully achieving synergistic optimization of mechanosensitive response and aggregation-induced emission. Studies show that this molecular engineering strategy can precisely control the mechanochromic behavior (reversible blue-green-yellow transition) and AIE properties of the material while maintaining excellent biocompatibility. This invention not only reveals the regulatory mechanism of substituent conjugation degree and spatial configuration on material properties, but also provides a designable molecular platform for developing novel intelligent luminescent materials, with significant application value in fields such as anti-counterfeiting encryption, bioimaging, and flexible optoelectronics.

[0073] This invention discloses a molecular engineering strategy for designing high-contrast mechanochromic materials. By modifying the substituents on the imidazole ring, the structure of the dithienylanthracene-phenanthreneimidazole skeleton is reconstructed, resulting in an anthracene-imidazolium derivative system with five different substitution configurations. These compounds, through substitution with substituents in different conjugated systems, significantly improve the aggregation-induced emission (AIE) performance of the materials while exhibiting high-contrast mechanochromic behavior. Five derivatives containing dithienylanthracene-phenanthreneimidazole—DTAPI-Ph, DTAPI-Na, DTAPI-An, DTAPI-Py, and DTAPI-TPA—were synthesized by introducing groups with different degrees of conjugation. This application investigates the effect of the steric hindrance effect of the substituents on optical properties. The dithienylanthracene-phenanthreneimidazole derivatives provided in this application all exhibit typical aggregation-induced emission enhancement (AIE) characteristics and reversible mechanochromic behavior, displaying high color contrast mechanochromic fluorescence ranging from blue-green to yellow. Substituent effects indicate that bulky coplanar and non-coplanar fluorophores play different roles in the construction of DTAPI-type AIE dyes, and the introduction of groups with different degrees of conjugation can effectively regulate the luminescent properties of the materials. Further research shows that they exhibit low cytotoxicity and have been successfully applied to live-cell imaging. This research lays the foundation for the design and development of high-contrast mechanoresponsive organic luminescent materials based on dithienylanthracene-phenanzimidazole in the aggregated state. This molecular design strategy based on substitution site engineering provides a novel structure-activity regulation paradigm for constructing aggregation-induced emission material systems with high-contrast mechanochromic properties, demonstrating significant theoretical value and application prospects in the development of next-generation optical information storage media, bioimaging dyes, and adaptive optoelectronic devices. The innovative strategy of this invention not only deepens the scientific understanding of the structure-performance relationship of organic photofunctional materials but also opens up a practically valuable implementation path for achieving precise customization of material properties and functional integration.

[0074] Although preferred embodiments of the present invention have been described, those skilled in the art, upon learning the inventive concept of the present invention, can make other changes and modifications to these embodiments, all of which fall within the scope of the present invention.

[0075] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. If such modifications and variations fall within the scope of equivalents of this invention, then this invention also intends to include these modifications and variations.

Claims

1. A light-emitting material based on a conjugated modified dithiophene group anthracene-phenanthroimidazole skeleton, characterized by, has the following general structure: ； In the formula, R is selected from any one of phenyl, naphthyl, anthryl, pyrenyl and triphenylamine.

2. The light-emitting material based on a conjugated modified dithiophene group anthracene-phenanthroimidazole skeleton according to claim 1, characterized in that, The light-emitting material is any one of the following compounds: 。 3. The method for producing a light-emitting material based on a conjugated modified dithiophene-based anthracene-phenanthroimidazole skeleton according to any one of claims 1 to 2, characterized by, The method comprises the following steps: 5-(10-(thiophene-2-yl)anthracen-9-yl)thiophene-2-carboxaldehyde, phenanthrenequinone, p-bromoaniline and ammonium acetate are subjected to condensation reaction in an organic solvent to obtain 1-(4-bromophenyl)-2-(5-(10-(thiophene-2-yl)anthracen-9-yl)thiophene-2-yl)-1H-phenanthro[9,10-d]imidazole; 1-(4-bromophenyl)-2-(5-(10-(thiophene-2-yl)anthracen-9-yl)thiophene-2-yl)-1H-phenanthro[9,10-d]imidazole, a conjugated boronic acid compound, a palladium catalyst and a basic compound are subjected to coupling reaction in an organic solvent to obtain a light-emitting material based on a conjugated modified dithiophene anthracene-phenanthroimidazole skeleton.

4. The method for producing a light-emitting material based on a conjugated modified dithiophene group anthracene-phenanthroimidazole skeleton according to claim 3, characterized by, The molar ratio of 5-(10-(thiophene-2-yl)anthracen-9-yl)thiophene-2-carboxaldehyde, phenanthrenequinone, p-bromoaniline and ammonium acetate is 1:1:1:4-8.

5. The method of producing a light emitting material based on a conjugated modified dithiophene group anthracene-phenanthroimidazole skeleton according to claim 3, characterized by, The condensation reaction is carried out at a temperature of 110-120°C for 3-4 hours, and the coupling reaction is carried out at a temperature of 80-85°C for 7-10 hours.

6. The method of producing a light emitting material based on a conjugated modified dithiophene group anthracene-phenanthroimidazole skeleton according to claim 3, characterized by, The conjugated boronic acid compound is selected from any one of phenylboronic acid, 1-naphthylboronic acid, 9-anthrylboronic acid, 1-pyrenylboronic acid and 4-(diphenylamino)phenylboronic acid.

7. The method of producing a light emitting material based on a conjugated modified dithiophene group anthracene-phenanthroimidazole skeleton according to claim 3, characterized by, The palladium catalyst is tetrakis(triphenylphosphine)palladium.

8. The method of producing a light emitting material based on a conjugated modified dithiophene group anthracene-phenanthroimidazole skeleton according to claim 3, characterized by, The basic compound is sodium carbonate.

9. The method of producing a light emitting material based on a conjugated modified dithiophene group anthracene-phenanthroimidazole skeleton according to claim 3, characterized by, The molar ratio of 1-(4-bromophenyl)-2-(5-(10-(thiophene-2-yl)anthracen-9-yl)thiophene-2-yl)-1H-phenanthro[9,10-d]imidazole and the conjugated boronic acid compound is 1:1.2-1.5, the amount of the palladium catalyst is 1-5 mol% of the total amount of 1-(4-bromophenyl)-2-(5-(10-(thiophene-2-yl)anthracen-9-yl)thiophene-2-yl)-1H-phenanthro[9,10-d]imidazole and the conjugated boronic acid compound, and the molar ratio of 1-(4-bromophenyl)-2-(5-(10-(thiophene-2-yl)anthracen-9-yl)thiophene-2-yl)-1H-phenanthro[9,10-d]imidazole and the basic compound is 1:1-1.

5.

10. Use of a luminescent material based on a conjugated modified dithiophene- anthracene-phenanthroimidazole skeleton in a mechanochromic sensor or in cell fluorescence imaging, characterized in that, The light-emitting material based on the conjugated modified dithiophene anthracene-phenanthroimidazole skeleton is the light-emitting material based on the conjugated modified dithiophene anthracene-phenanthroimidazole skeleton according to any one of claims 1-2.

Images