Colorless transparent crystal of organic light-emitting macrocycle and preparation method and application thereof

Abstract

The invention belongs to the technical field of organic light-emitting crystal materials, and particularly relates to colorless transparent crystals of organic light-emitting macrocycles and a preparation method and application of the colorless transparent crystals. According to the colorless transparent crystal of the organic light-emitting macrocycle, a dibenzofuran compound serves as a photoelectric element, diarylethene serves as an intelligent element, the dibenzofuran compound and the diarylethene are subjected to conjugate coupling through reasonable design and synthesis, and the O-(2 + 2) novel intelligent molecular macrocycle is obtained. The O-(2 + 2) furyl organic light-emitting macrocyclic colorless transparent crystal is obtained through a slow evaporation method, the crystal is subjected to UV illumination, the crystal is changed from racemization to meso-rotation from racemization, configuration transformation in stereochemistry occurs, and crystal elongation is achieved. The photomechanical property of the organic crystal can be realized by performing UV illumination on the crystal.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of organic luminescent crystal materials, and more particularly relates to a colorless transparent crystal of an organic luminescent macrocycle and a preparation method and application thereof. BACKGROUND

[0002] Photo-mechanical responsive organic crystals, as a kind of smart materials capable of directly converting light energy into mechanical deformation, have become a research hotspot in the field of smart materials due to their unique advantages such as fast response speed, high energy conversion efficiency, and non-contact control mode, and have shown irreplaceable application potential in the fields of micro-robot driving, precise drug delivery, flexible electronic devices, and light-controlled microfluidic valves. For example, in the field of micro-robots, photo-mechanical crystals can be used as driving units for micro-walking mechanisms to achieve precise movement at the millimeter or even micrometer level through light irradiation; in the field of drug delivery, the light-controlled deformation characteristics of photo-mechanical crystals are expected to achieve timed and quantitative release of drugs at lesion sites, greatly improving treatment efficiency and reducing side effects.

[0003] On the one hand, traditional organic crystals generally have brittleness problems during photo-mechanical response; during photo-mechanical response, organic crystals often crack into small fragments due to internal stress accumulation, making it difficult to maintain the integrity of the single crystal structure. On the other hand, the main mechanism of photo-mechanical response of current organic crystals is mainly photochemical reaction, but there is a certain contradiction between the essential characteristics of photochemical reaction and the intrinsic properties of crystal materials. The hydrogen bonds and pi-pi interactions within organic crystals can significantly inhibit photochemical reactions, severely limiting the development and application of photo-mechanical responsive organic crystals. SUMMARY

[0004] To solve the above technical problems, the present application provides a colorless transparent crystal of an organic luminescent macrocycle, a preparation method and application thereof, and a matching photo-mechanical response strategy, thereby realizing excellent photo-mechanical properties of organic crystals and solving the technical problems of existing organic crystals. The colorless transparent crystal of an organic luminescent macrocycle obtained by a specific preparation process has two core advantages: first, it can effectively maintain the stability of the crystal structure during the entire photo-mechanical response process, ensuring the good integrity of the crystal without being damaged, thereby solving the industry problem of balancing "response function implementation" and "crystal form preservation". Second, a new strategy is developed to achieve the photo-mechanical response of organic crystals by UV irradiation of the crystal, which changes from racemic to meso and undergoes configuration transformation in stereochemistry, thereby realizing the stimulus response of the photo-mechanical properties of organic crystals, rather than through photochemical reaction. This lays a key foundation for the application of organic luminescent macrocycle materials in precise light-driven devices and intelligent response systems.

[0005] Based on the above technical purposes, the present application is implemented by the following technical solutions: The application protects a colorless transparent crystal of an organic luminescent macrocycle, wherein the structural formula of the organic luminescent macrocycle is: .

[0006] The application also protects a preparation method of the colorless transparent crystal of the organic luminescent macrocycle, comprising the following steps: To prepare the organic luminescent macrocycle, experiments are carried out in a protective gas atmosphere: first, DAE and 2,8-dibromodibenzofuran are used as reaction substrates, and the reaction substrates, a palladium catalyst, a ligand, a phase transfer catalyst and an inorganic base are added to a specified solvent, after the system is fully dissolved and uniformly mixed, a bond formation reaction between the substrates is realized through a Suzuki-Miyaura coupling reaction, and finally the target organic luminescent macrocycle is obtained, the organic luminescent macrocycle is crystallized, and a slow evaporation method (slow evaporation of dichloromethane) is used to obtain the colorless transparent crystal of the organic luminescent macrocycle.

[0007] wherein the complete chemical name of the compound DAE is: 2,2'-(((perfluorocyclopent-1-en-1,2-diyl)bis(5-methylthiophene-4,2-diyl))bis(4,1-phenylene))bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolane).

[0008] Preferably, the molar ratio relationship of DAE and 2,8-dibromodibenzofuran is 1:0.95~1.05, the molar ratio relationship of DAE and the palladium catalyst is 1.25:0.1~0.3, the molar ratio relationship of DAE and the phase transfer catalyst is 1.25:0.2~0.5, the molar ratio relationship of DAE and the ligand is 1.25:0.2~0.5, and the molar ratio relationship of DAE and the inorganic base is 1.25:20~50.

[0009] Preferably, the conditions of the Suzuki-Miyaura coupling reaction are: the reaction temperature is 75℃~85℃, and the reaction time is 5 days~7 days.

[0010] Preferably, the palladium catalyst is selected from at least one of PdCl2(dppf)CH2Cl2, Pd2(dba)3 and PdCl2.

[0011] Preferably, the phase transfer catalyst is selected from tetrabutylammonium bromide (TBAB), tetrabutylammonium chloride (TBAC), tetrabutylammonium hydrogen sulfate (TBAHS) or cetyltrimethylammonium bromide (CTAB).

[0012] Preferably, the ligand is selected from 2-dicyclohexylphosphino-2'-methylbiphenyl (SPhos), 2-dicyclohexylphosphino-2',4',6'-triisopropylbiphenyl (XPhos), 1,1'-bis(diphenylphosphino)ferrocene (dppf) or tricyclohexylphosphine (PCy3).

[0013] Preferably, the inorganic base is K2CO3.

[0014] Preferably, the solvent is a mixture of toluene and water, and the volume ratio of toluene to water is 13-15:2.

[0015] Preferably, after the Suzuki-Miyaura coupling reaction is completed, the post-reaction system is concentrated, and after the precipitate is precipitated, it is dissolved in a suitable organic solvent, and then the two phases are separated by liquid separation operation, and the organic phase is accurately collected; the organic phase is dried to remove residual water, and then subjected to a solvent removal step to obtain a crude product, and finally the crude product is purified by silica gel column chromatography to successfully prepare an organic light-emitting macrocycle.

[0016] Preferably, when the DAE is 2,2'-(((perfluorocyclopent-1-en-1,2-diyl)bis(5-methylthiophene-4,2-diyl))bis(4,1-phenylene))bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolane), the organic light-emitting macrocyclic compound after silica gel column chromatography is O-(2+2).

[0017] Preferably, the preparation of DAE is a prior art, and the DAE is prepared according to the following steps: S1, under a nitrogen atmosphere, 3-bromo-2-methylthiophene and triisopropyl borate are subjected to lithium halogen exchange of 3-bromo-2-methylthiophene, i.e. boron esterification reaction, in tetrahydrofuran as solvent in the presence of n-butyllithium, reaction mechanism: lithium-halogen exchange reaction, the nucleophilic Li⁺ in n-butyllithium (n-BuLi) exchanges with the Br atom on the thiophene ring to generate 3-methyl-2-thiophenyl lithium (nucleophilic intermediate) and n-butyl bromide (n-BuBr, byproduct); nucleophilic substitution reaction, boron-carbon bond construction, the 3-methyl-2-thiophenyl lithium (nucleophile) generated in the first step attacks the electron-deficient boron atom (B) in triisopropyl borate to replace one of the isopropoxy groups (-O-iPr) to form 3-methyl-2-thiophene boronic acid diisopropyl ester (boron ester intermediate); hydrochloric acid quenching reaction, the target boronic acid is generated, the boron ester intermediate (containing -O-iPr group) is hydrolyzed with water (H2O) in hydrochloric acid, the isopropoxy group (-O-iPr) is replaced by the hydroxyl group (-OH), and finally 3-methyl-2-thiophene boronic acid (target product) is generated, while releasing isopropyl alcohol (iPrOH) and LiCl (dissolved in the aqueous phase, which can be separated by post-treatment); reaction purpose: through the three steps of "lithium-halogen exchange → reaction with borate → acid quenching", the bromine atom (-Br) on the thiophene ring in the raw material is converted into a boronic acid group, i.e. -B(OH)2, to prepare the key intermediate 2-methyl-3-thiophene boronic acid for the subsequent Suzuki-Miyaura coupling reaction.

[0018] S2, under the atmosphere of nitrogen, 2-methyl-3-thiophene boronic acid and 1,2-dichloroperfluorocyclopentene were subjected to double Suzuki coupling reaction in the presence of palladium catalyst, tricyclohexylphosphine, cesium fluoride, the reaction mechanism: oxidative addition, the catalyst precursor Pd2dba3·CHCl3was first converted into active Pd(0) species in the presence of ligand PCy3; Pd(0) attacked one C-Cl bond of 1,2-dichlorocyclopentene, Pd(0) was oxidized to Pd(II) to form the "hexafluorocyclopentene-Pd(II)-Cl" intermediate (first oxidative addition); transmetalation, 2-methyl-3-thiophene boronic acid was converted into "thiophene boronic acid fluoride salt" with stronger nucleophilicity in the presence of inorganic base CsF; the fluoride salt reacted with the "hexafluorocyclopentene-Pd(II)-Cl" intermediate, the Cl on Pd(II) was replaced by the thiophene ring to form the "hexafluorocyclopentene-Pd(II)-thiophene" intermediate; reductive elimination, the "hexafluorocyclopentene-Pd(II)-thiophene" intermediate underwent reductive elimination, Pd(II) returned to Pd(0) (re-entered the cycle), and "monothiophene-substituted hexafluorocyclopentene chloride" (the first coupling product) was generated, i.e. 3,3'-(3,3,4,4,5,5-hexafluoro-1-cyclopentene-1,2-diyl) bis[2-methylthiophene]. Reaction purpose: through Suzuki-Miyaura coupling reaction, two chlorine atoms (-Cl) in 1,2-dichlorocyclopentene molecule were respectively connected with the thiophene rings of two molecules of 2-methyl-3-thiophene boronic acid to form C-C bonds, and the target product 3,3'-(3,3,4,4,5,5-hexafluoro-1-cyclopentene-1,2-diyl) bis[2-methylthiophene] was finally synthesized, realizing the precise splicing of "double thiophene ring" and "hexafluorocyclopentene skeleton", and providing a key molecular structure for the preparation of subsequent functional materials.

[0019] S3. Under a nitrogen atmosphere, using m-xylene as a solvent, and in the presence of a palladium catalyst, the ligand 2,2'-bipyridine, and the inorganic base Ag2CO3, 3,3′-(3,3,4,4,5,5-hexafluoro-1-cyclopenten-1,2-diyl)bis[2-methylthiophene] and p-bromoiodobenzene underwent a Pd-catalyzed di-CH arylation reaction. The reaction mechanism is as follows: catalyst activation; PdCl2 coordinates with 2,2'-bipyridine (bpy) at 70℃ to form a stable Pd(II)-bpy complex (active catalyst). Bipyridine acts as a bidentate ligand to stabilize the Pd center and regulate its electronic properties; CH bond activation; the active Pd(II)-bpy complex interacts with the dithiophene substrate, selectively activating the CH bond at the α-position of the thiophene ring (due to the ortho-position effect of the methyl group, the CH bond at this site has higher activity), generating " The intermediate "thiophene-Pd(II)-H" is formed, and H⁺ is released (neutralized by Ag₂CO₃); transmetalation is performed, with bromoiodobenzene (Ar-I, where I has a stronger leaving ability than Br) as the aryl source. Its Ar-I bond reacts with the "thiophene-Pd(II)-H" intermediate, and the Ar group replaces the H on Pd(II) to form the "thiophene-Pd(II)-Ar" intermediate (Ar is 4-bromophenyl), and I⁻ is released (which combines with Ag⁺ to form AgI precipitate, driving the reaction forward); reductive elimination is performed, and the "thiophene-Pd(II)-Ar" intermediate undergoes reductive elimination, and Pd(II) is converted to Pd(0), while generating a "monoarylated thiophene derivative"; Pd(0) is oxidized back to Pd(II) under the action of Ag₂CO₃ (oxidant) and re-enters the catalytic cycle. The objective of this reaction is to introduce a 4-bromophenyl group into the α-position (the vacancy adjacent to the methyl group) of the thiophene ring of a bisthiophene derivative (3,3′-(3,3,4,4,5,5-hexafluoro-1-cyclopenten-1,2-diyl)bis[2-methylthiophene]) via Pd-catalyzed CH bond activation and cross-coupling, thereby synthesizing the target product 3,3′-(perfluorocyclopenten-1-ene-1,2-diyl)bis(5-(4-bromophenyl)-2-methylthiophene). This reaction introduces a bromine functional group into the molecule by constructing a biaromatic structure of a thiophene ring-benzene ring (which can be further used for subsequent coupling reactions), providing a key molecular structure for the preparation of subsequent functional materials.

[0020] S4. Under a nitrogen atmosphere, using toluene as a solvent, and in the presence of a palladium catalyst and the inorganic base potassium acetate, 3,3'-(perfluorocyclopentan-1-en-1,2-diyl)bis(5-(4-bromophenyl)-2-methylthiophene) and pinacol diboron ester were subjected to a Pd-catalyzed diboron esterification reaction. The reaction mechanism was as follows: catalyst activation and oxidative addition. The catalyst precursor PdCl2(dppf)・CH2Cl2 (dppf=1,1'-bis(diphenylphosphine)ferrocene) was first converted into an active Pd(0) species under alkaline conditions. Pd(0) attacked the C-Br bond of the substrate, and Pd(0) was oxidized to Pd(II), forming a "substrate-Pd(II)-Br" intermediate (first oxidative addition). Transmetallation occurred, and pinacol diboron ester (B2pin2) reacted with the "substrate-Pd" intermediate under the action of KOAc. In the (II)-Br” intermediate reaction, the Bpin group replaces the Br atom on Pd(II), forming the “substrate-Pd(II)-Bpin” intermediate; simultaneously, KOBr is generated (soluble in the aqueous phase and can be separated by extraction). Reductive elimination occurs, and the “substrate-Pd(II)-Bpin” intermediate undergoes reductive elimination, reducing Pd(II) to Pd(0) (re-entering the catalytic cycle), generating the “single-Bpin substituted intermediate product” (the first boron esterification product), i.e., DAE. The reaction objective is to replace the bromine atoms (-Br) on the two benzene rings of the bisthiophene derivative molecule with pinacol boronic acid ester groups (-Bpin, Bpin = 4,4,5,5-tetramethyl-1,3,2-dioxaborane) through Pd-catalyzed cross-coupling, preparing the target product containing a diboronic acid ester structure. The bis-Bpin group of this target product is the key nucleophile for the subsequent Suzuki-Miyaura coupling reaction.

[0021] Furthermore, in step S1, the molar ratio of triisopropyl borate, n-butyllithium, and 3-bromo-2-methylthiophene is 18~22:18~22:10.

[0022] Furthermore, in step S1, the conditions for the boron esterification reaction are: stirring at -78℃ to -20℃ for 18 hours.

[0023] Furthermore, in step S2, the molar ratio of 2-methyl-3-thiopheneboronic acid to 1,2-dichloroperfluorocyclopentene is 14~16:5, the molar ratio of palladium catalyst to 1,2-dichloroperfluorocyclopentene is 1:19~21, the molar ratio of tricyclohexylphosphine to 1,2-dichloroperfluorocyclopentene is 1:19~21, and the molar ratio of cesium fluoride to 1,2-dichloroperfluorocyclopentene is 8~10:1.

[0024] Furthermore, in step S2, the conditions for the double Suzuki coupling reaction are: stirring at 115℃~125℃ for 16h~18h.

[0025] Furthermore, in step S3, the molar ratio of p-bromoiodobenzene to 3,3′-(3,3,4,4,5,5-hexafluoro-1-cyclopenten-1,2-diyl)bis[2-methylthiophene] is 14~16:5, and the molar ratio of palladium catalyst to 3,3′-(3,3,4,4,5,5-hexafluoro-1-cyclopenten-1,2-diyl)bis[2-methylthiophene] is 19~21:20. The molar ratio of ligand 2,2'-bipyridine to 3,3′-(3,3,4,4,5,5-hexafluoro-1-cyclopenten-1,2-diyl)bis[2-methylthiophene] is 19~21:20, and the molar ratio of inorganic base Ag2CO3 to 3,3′-(3,3,4,4,5,5-hexafluoro-1-cyclopenten-1,2-diyl)bis[2-methylthiophene] is 14~16:5.

[0026] Furthermore, in step S3, the conditions for the bisCH arylation reaction are: stirring at 125℃~135℃ for 13h~14h.

[0027] Furthermore, in step S4, the molar ratio of pinacol diboronate to 3,3'-(perfluorocyclopentan-1-en-1,2-diyl)bis(5-(4-bromophenyl)-2-methylthiophene) is 24~26:1, the molar ratio of palladium catalyst to 3,3'-(perfluorocyclopentan-1-en-1,2-diyl)bis(5-(4-bromophenyl)-2-methylthiophene) is 1:9~11, and the molar ratio of inorganic base potassium acetate to 3,3'-(perfluorocyclopentan-1-en-1,2-diyl)bis(5-(4-bromophenyl)-2-methylthiophene) is 14~16:5.

[0028] Furthermore, in step S4, the conditions for the diboron esterification reaction are: stirring at 85℃~95℃ for 22h~24h.

[0029] Furthermore, in steps S2, S3, and S4, the palladium catalyst is selected from at least one of PdCl2(dppf)CH2Cl2, Pd2(dba)3, or PdCl2.

[0030] This invention also provides the application of colorless and transparent organic light-emitting macrorings in the preparation of photomechanically responsive materials, which is a new strategy for the stimulus response of the photomechanical properties of organic crystals.

[0031] Preferably, the application method is as follows: by irradiating the colorless and transparent crystal of the organic light-emitting macroring with UV light, the colorless and transparent crystal of the organic light-emitting macroring changes from exocycly to mesocycly, undergoing a configuration transformation in stereochemistry, thereby achieving crystal elongation.

[0032] The stimulation response of the photomechanical properties of the colorless transparent crystal of the organic light-emitting macroring includes the following steps: applying 365nm light to the colorless transparent crystal of the organic light-emitting macroring under a fluorescence microscope and observing the dynamic photostimulation response process of the colorless transparent crystal of the organic light-emitting macroring.

[0033] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention provides a colorless and transparent crystal of an organic light-emitting macroring, the structural formula of which is: The method uses dibenzofuran (DBF) as the photoelectric unit and diarylethene (DAE) as the intelligent unit. Through rational design and synthesis, the two are conjugated to obtain a novel O-(2+2) intelligent molecular macrocycle. The role of dibenzofuran is to enhance the stability of the eutectic by strong intermolecular interactions, improve the efficiency of charge transport and luminescence performance, and promote heteroatom-guided directional assembly. Its rigid oxygen heterocyclic structure provides structural framework support and functional regulation for the eutectic. Then, by stimulating the diarylethene response to UV light, the crystal changes from racemic to meso, undergoing a stereochemical configuration transformation, and realizing photomechanical response—crystal elongation.

[0034] This invention uses DAE and 2,8-dibromodibenzofuran as reactants. The reactants, palladium catalyst, phase transfer catalyst, ligand, and inorganic base are dissolved in a solvent and, under a protective gas atmosphere, undergo a Suzuki-Miyaura coupling reaction, followed by crystallization to prepare colorless, transparent crystals of organic luminescent macrocycles. The core mechanism of the Suzuki-Miyaura coupling reaction is based on Pd(0) / Pd(II) as the catalytic cycle center, specifically consisting of three steps: oxidative addition, where a low-valent Pd(0) catalyst reacts with an electrophilic reagent (usually an aryl halide Ar-X), oxidizing Pd(0) to Pd(II) and simultaneously forming Ar-Pd- The X intermediate is the initiation step of the reaction, determining the initial activity of the reaction. Transmetallization occurs when an organoboron reagent (such as Ar'-B(OH)2) reacts with an inorganic base to form a more nucleophilic borate (Ar'-B(OH)3⁻), which then reacts with the Ar-Pd-X intermediate. The Ar' group replaces X on Pd(II), forming the Ar-Pd-Ar' intermediate. This step is a key precursor step for constructing new C-C bonds. Reductive elimination occurs when the Ar-Pd-Ar' intermediate undergoes reductive elimination, reducing Pd(II) back to Pd(0) (re-entering the catalytic cycle) and releasing the target product Ar-Ar', completing one catalytic cycle.

[0035] The reaction is usually carried out in a water-organic two-phase system (the organoboron reagent is dissolved in the aqueous phase and the aryl halide is dissolved in the organic phase), and the core role of the phase transfer catalyst is to "bridge".

[0036] Ligands are the "core assistants" that ensure the activity and stability of Pd catalysts. They stabilize the Pd(0) species, preventing Pd(0) from agglomerating to form inactive palladium black and maintaining the dispersion of the catalyst in the reaction system. Ligands also increase the electron cloud density of the Pd center: electron-rich ligands enhance the nucleophilicity of Pd(0) and accelerate the oxidative addition step. Ligands regulate steric hindrance: sterically hindered ligands can suppress side reactions (such as β-H elimination) while promoting reductive elimination steps, thus improving product selectivity.

[0037] Inorganic bases are indispensable "driving agents" for the reaction, and their main functions include: Activating organoboron reagents: Reacting with organoboron reagents (such as Ar-B(OH)2) to generate borates (such as Ar-B(OH)3⁻) that are more prone to transmetallization, thus enhancing nucleophilicity. Neutralizing reaction byproducts: In the transmetallization step, the base neutralizes the generated HX (such as HBr), preventing the acidic environment from inhibiting the activity of the Pd catalyst and simultaneously promoting the reaction in the forward direction.

[0038] 2. The present invention also provides a method for preparing colorless and transparent crystals of organic light-emitting macrocyclic rings, which uses DAE and 2,8-dibromodibenzofuran as reactants, dissolving the reactants, palladium catalyst, phase transfer catalyst, ligand and inorganic base together in a solvent, and then performing a Suzuki-Miyaura coupling reaction under a protective gas atmosphere, followed by crystallization by slow evaporation to prepare colorless and transparent crystals of organic light-emitting macrocyclic rings.

[0039] 3. The colorless and transparent organic light-emitting macrocyclic crystals prepared by this invention possess a unique photostimulation response strategy, specifically manifested in: photomechanical response of non-photochemical organic crystals; good stability: the crystal maintains good integrity after photostimulation response; high sensitivity: the crystal responds rapidly to photostimulation; and wide applicability: the method of this invention is applicable to a variety of organic light-emitting materials and has broad application prospects. Furthermore, this invention not only overcomes the limitations of existing technologies but also provides more efficient and flexible technical solutions for fields such as microrobot actuation, precision drug delivery, flexible electronic devices, and photo-controlled microfluidic valves. Attached Figure Description

[0040] Figure 1 The synthetic reaction formula for preparing 2-methyl-3-thiopheneboronic acid is shown in Example 1.

[0041] Figure 2 The synthetic reaction formula for preparing 3,3′-(3,3,4,4,5,5-hexafluoro-1-cyclopentene-1,2-diyl)bis[2-methylthiophene] is shown in Example 1.

[0042] Figure 3The synthetic reaction formula for preparing 3,3'-(perfluorocyclopent-1-ene-1,2-diyl)bis(5-(4-bromophenyl)-2-methylthiophene) is given in Example 1.

[0043] Figure 4 The synthetic reaction formula for preparing DAE: 2,2'-(((perfluorocyclopent-1-ene-1,2-diyl)bis(5-methylthiophene-4,2-diyl))bis(4,1-phenylene))bis(4,4,5,5-tetramethyl-1,3,2-dioxaborane) is shown in Example 1.

[0044] Figure 5 The synthetic reaction formula for preparing O-(2+2) is shown in Example 1.

[0045] Figure 6 The 1H NMR spectrum of 2-methyl-3-thiopheneboronic acid prepared in Example 1.

[0046] Figure 7 The 1H NMR spectrum of 3,3′-(3,3,4,4,5,5-hexafluoro-1-cyclopentene-1,2-diyl)bis[2-methylthiophene] prepared in Example 1.

[0047] Figure 8 The 1H NMR spectrum of 3,3'-(perfluorocyclopent-1-ene-1,2-diyl)bis(5-(4-bromophenyl)-2-methylthiophene) prepared in Example 1.

[0048] Figure 9 The 1H NMR spectrum of DAE: 2,2'-(((perfluorocyclopent-1-ene-1,2-diyl)bis(5-methylthiophene-4,2-diyl))bis(4,1-phenylene))bis(4,4,5,5-tetramethyl-1,3,2-dioxaborane) prepared in Example 1.

[0049] Figure 10 The photon nuclear magnetic resonance (NMR) spectrum of the colorless, transparent organic luminescent macrocyclic crystal prepared in Example 1 is shown.

[0050] Figure 11 This is a fluorescence microscope image of the colorless transparent crystal of the organic light-emitting macroring prepared in Example 1 before UV irradiation.

[0051] Figure 12 This is a single-crystal structure diagram of the colorless transparent crystal of the organic light-emitting macroring prepared in Example 1 before UV irradiation.

[0052] Figure 13 The image shows a fluorescence microscope image of the colorless transparent crystal of the organic light-emitting macroring prepared in Example 1 after UV irradiation.

[0053] Figure 14This is a single-crystal structure diagram of the colorless transparent crystal of the organic light-emitting macroring prepared in Example 1 after UV irradiation.

[0054] Figure 15 The image shows the single-crystal structure of the colorless transparent organic light-emitting macroring prepared in Example 1 before and after illumination. Detailed Implementation

[0055] To enable those skilled in the art to better understand and implement the technical solutions of the present invention, the present invention will be further described below with reference to specific embodiments and accompanying drawings. However, the embodiments described are not intended to limit the present invention. Unless otherwise specified, the experimental methods and detection methods described in the following embodiments are conventional methods; unless otherwise specified, the reagents and materials described are commercially available.

[0056] This invention provides a method for preparing colorless and transparent crystals of organic light-emitting macrorings, comprising the following steps: Under a protective gas atmosphere, the reaction substrates DAE and 2,8-dibromodibenzofuran, along with a palladium catalyst, ligand, phase transfer catalyst, and inorganic base, were added to a specified solvent. After the system was fully dissolved and mixed, bonding between the substrates was achieved through a Suzuki-Miyaura coupling reaction, ultimately yielding a colorless and transparent crystal of the target organic luminescent macrocycle.

[0057] The full chemical name of compound DAE is: 2,2'-(((perfluorocyclopent-1-en-1,2-diyl)bis(5-methylthiophene-4,2-diyl))bis(4,1-phenylene))bis(4,4,5,5-tetramethyl-1,3,2-dioxaborane). The organic luminescent macrocycle purified by silica gel column chromatography is O-(2+2). Colorless and transparent crystals of O-(2+2)furanyl organic luminescent macrocycle were obtained by slow evaporation (slow evaporation of dichloromethane).

[0058] External stimulation: The colorless transparent crystal of the above-mentioned organic light-emitting macroring was illuminated with 365nm light under a fluorescence microscope, and the dynamic photostimulation response process of the crystal was observed.

[0059] The invention will now be described through examples, as detailed below: Example 1 The method for preparing colorless and transparent crystals of organic light-emitting macrocyclic rings includes the following steps: The preparation of S1,2-methyl-3-thiopheneboronic acid, and the synthetic route are as follows: Figure 1 As shown: In a dry 250 mL three-necked flask, add 5.3102 g (30 mmol) of 3-bromo-2-methylthiophene, 14.1 mL (60 mmol) of triisopropyl borate, and 110 mL of tetrahydrofuran. Mix thoroughly with a magnetic stirrer to obtain a homogeneous mixture. Purge the mixture with nitrogen gas to completely remove oxygen from the solvent and reaction system. Then, at -78 °C, slowly add 24 mL (60 mmol) of 2.5 M n-butyllithium solution to the reaction system through a dropping funnel. After the n-hexane solution and n-butyllithium solution were added dropwise, the temperature was slowly raised to -20°C and stirred at -20°C for 1 hour. The mixture was then allowed to naturally warm to room temperature, and the reaction was quenched with a 1 mol / L hydrochloric acid aqueous solution to obtain the reaction solution. The resulting reaction solution was extracted twice with ethyl acetate, washed with water, dried with anhydrous Na₂SO₄, and then evaporated to dryness. Recrystallization with acetonitrile yielded 2-methyl-3-thiopheneboronic acid (2.1803 g, yield 52%), a white solid. The 1H NMR spectrum is shown below. Figure 6 As shown.

[0060] The preparation of S2,3,3′-(3,3,4,4,5,5-hexafluoro-1-cyclopenten-1,2-diyl)bis[2-methylthiophene] is described by the following synthetic route: Figure 2 As shown: In a 25 mL Schlenk tube, add 2-methyl-3-thiopheneboronic acid (2.5560 g, 18 mmol), Pd2dba3•CHCl3 (0.3105 g, 0.3 mmol), PCy3 (0.0336 g, 0.12 mmol), and CsF (8.2080 g, 54 mmol). Immediately and carefully evacuate the tube three times using a double-row tube to ensure complete deoxygenation of the entire system. Then add 1,2-dichlorocyclopentene (899 μL). 6 mmol) and 18 mL of deoxygenated toluene / water mixed solvent (volume ratio 10 / 1) were added, heated to 120 °C and reacted for 16 h. After the reaction was completed, the mixture was cooled to room temperature, filtered through a short silica gel column, and the filtrate was evaporated to dryness. The product was purified by silica gel column chromatography using petroleum ether as the eluent to give 3,3′-(3,3,4,4,5,5-hexafluoro-1-cyclopenten-1,2-diyl)bis[2-methylthiophene] (2.1228 g, yield 96%). The 1H NMR spectrum is shown below. Figure 7 As shown.

[0061] The preparation of S3,3,3'-(perfluorocyclopent-1-en-1,2-diyl)bis(5-(4-bromophenyl)-2-methylthiophene) is shown in the following synthetic route. Figure 3 As shown: In a 25 mL Schlenk tube, PdCl2 (0.2726 g, 1.54 mmol) and 2,2'-bipyridine (0.2402 g, 1.54 mmol) were added. Immediately, the mixture was carefully evacuated three times using a double-row tube to ensure complete deoxygenation. Then, dry m-xylene (2.5 mL) was added, and the reaction mixture was heated at 70 °C for 0.5 h. Next, under a nitrogen stream, 3,3′-(3,3,4,4,5,5-hexafluoro-1-cyclopenten-1,2-diyl)bis[2-methylthiophene] (0.5649 g, ...) was added to the Schlenk tube. 1.54 mmol), p-bromoiodobenzene (1.3033 g, 4.61 mmol), Ag₂CO₃ (1.2724 g, 4.61 mmol), and 2.8 mL of dry m-xylene were added. The mixture was then heated and stirred in an oil bath at 130 °C for 13 h. After the reaction was complete, the reaction system was cooled to room temperature, filtered through a short silica gel column, and the filtrate was evaporated to dryness. Using petroleum ether as the eluent, the product was purified by silica gel column chromatography to give 3,3'-(perfluorocyclopentan-1-en-1,2-diyl)bis(5-(4-bromophenyl)-2-methylthiophene) (0.4845 g, yield 47%). The 1H NMR spectrum is shown below. Figure 8 As shown.

[0062] The preparation of S4, DAE: 2,2'-(((perfluorocyclopentan-1-en-1,2-diyl)bis(5-methylthiophene-4,2-diyl))bis(4,1-phenylene))bis(4,4,5,5-tetramethyl-1,3,2-dioxaborane), the synthetic route is as follows: Figure 4 As shown: In a Schlenk tube, 3,3'-(perfluorocyclopentan-1-en-1,2-diyl)bis(5-(4-bromophenyl)-2-methylthiophene) (1.3211 g, 1.95 mmol), pinacol diborate (1.2383 g, 4.88 mmol), PdCl2(dppf).CH2Cl2 (0.1597 g, 0.195 mmol), KOAc (0.9555 g, 9.75 mmol), and 40 mL of toluene were added. The mixture was then carefully evacuated three times using a double-row tube to ensure complete deoxygenation. The reaction mixture was then heated to 90°C and heated for 24 hours. After the reaction was completed, the mixture was cooled to room temperature and quenched with 40 mL of water. The organic phase was extracted with dichloromethane (20 mL × 3 times), washed three times with water (20 mL × 3 times), and dried over anhydrous Na₂SO₄. The crude product was purified by silica gel column chromatography using a gradient elution of petroleum ether / dichloromethane (3:1 to 1:1) to give 2,2'-(((perfluorocyclopentan-1-en-1,2-diyl)bis(5-methylthiophene-4,2-diyl))bis(4,1-phenylene))bis(4,4,5,5-tetramethyl-1,3,2-dioxaborane) (0.8927 g, yield 59%). The 1H NMR spectrum is shown below.Figure 9 As shown.

[0063] The preparation of S5 and O-(2+2) is shown in the following synthetic route. Figure 5 As shown: In a Schlenk tube, the following reactants were added: 2,8-dibromodibenzofuran (0.2038 g, 0.625 mmol), 2,2'-(((perfluorocyclopentan-1-en-1,2-diyl)bis(5-methylthiophene-4,2-diyl))bis(3,1-phenylene))bis(4,4,5,5-tetramethyl-1,3,2-dioxaborane) (0.4825 g, 0.625 mmol), Pd2(dba)3 catalyst (0.0960 g, 0.1 mmol), TBAB phase transfer catalyst (0.0644 g, 0.2 mmol), SPhos ligand (0.0822 g, 0.2 mmol), and no... Organic base K₂CO₃ (2.5875 g, 18.75 mmol), toluene solvent (315 mL), and water (45 mL) were used. The system was subjected to three freeze-drying cycles to ensure complete deoxygenation. The reaction system was then heated to 80 °C and reacted for 120 h to carry out the Suzuki-Miyaura coupling reaction. After the reaction, the mixture was cooled to room temperature, and 100 mL of water was added to quench the reaction. The organic phase was extracted sequentially with dichloromethane (100 mL × 3), washed three times with water (50 mL × 3), and dried over anhydrous Na₂SO₄. The crude product was purified by silica gel column chromatography with a petroleum ether / dichloromethane gradient elution of 10:1 to 5:1 to obtain O⁻(2+2). The 1H NMR spectrum is shown below. Figure 10 As shown.

[0064] S6. Preparation of colorless and transparent crystals of organic light-emitting macrorings: O-(2+2) (0.01 mmol) was added to a 50 mL reagent bottle, followed by 30 mL of dichloromethane solvent. The bottle was then placed open in a 25°C incubator for 24 h to obtain colorless and transparent crystals of O-(2+2)furanyl organic luminescent macrocycles. The crystal morphology is as follows: Figure 11 As shown.

[0065] Example 2 The preparation method of colorless and transparent crystals of organic light-emitting macrorings is the same as steps S1-S4 and S6 in Example 1, except that step S5 includes the following steps: The preparation of S5 and O-(2+2) is shown in the following synthetic route. Figure 5 As shown: In a Schlenk tube, the following reactants were added: 2,8-dibromodibenzofuran (0.1936 g, 0.589 mmol), 2,2'-(((perfluorocyclopentan-1-en-1,2-diyl)bis(5-methylthiophene-4,2-diyl))bis(3,1-phenylene))bis(4,4,5,5-tetramethyl-1,3,2-dioxaborane) (0.4825 g, 0.625 mmol), Pd2(dba)3 catalyst (0.192 g, 0.2 mmol), TBAB phase transfer catalyst (0.1288 g, 0.4 mmol), and SPhos ligand (0.1644 g, 0.4 mmol). The reaction mixture was prepared with 2.76 g of inorganic base K2CO3 (20 mmol), 312 mL of toluene solvent, and 48 mL of water. The mixture was subjected to three freeze-drying cycles to ensure complete deoxygenation. The reaction system was then heated to 75 °C and heated for 7 days to carry out the Suzuki-Miyaura coupling reaction. After the reaction was completed, the mixture was cooled to room temperature and 100 mL of water was added to quench the reaction. The organic phase was extracted with dichloromethane (100 mL × 3), washed three times with water (50 mL × 3), and dried with anhydrous Na2SO4. The crude product was purified by silica gel column chromatography with a gradient elution of petroleum ether / dichloromethane = 10:1 to 5:1 to obtain O-(2+2).

[0066] Example 3 The preparation method of colorless and transparent crystals of organic light-emitting macrorings is the same as steps S1-S4 and S6 in Example 1, except that step S5 includes the following steps: The preparation of S5 and O-(2+2) is shown in the following synthetic route. Figure 5 As shown: In a Schlenk tube, the following reactants were added: 2,8-dibromodibenzofuran (0.21399 g, 0.65625 mmol), 2,2'-(((perfluorocyclopentan-1-en-1,2-diyl)bis(5-methylthiophene-4,2-diyl))bis(3,1-phenylene))bis(4,4,5,5-tetramethyl-1,3,2-dioxaborane) (0.4825 g, 0.625 mmol), Pd2(dba)3 catalyst (0.288 g, 0.3 mmol), TBAB phase transfer catalyst (0.161 g, 0.5 mmol), and SPhos ligand (0.2055 g, 0.5 mmol). The reaction mixture was prepared with 50 mmol of inorganic base K2CO3 (6.9 g, 50 mmol), 318 mL of toluene solvent, and 42 mL of water. The mixture was subjected to three freeze-drying cycles to ensure complete deoxygenation. The reaction mixture was then heated to 85 °C and reacted for 6 days to carry out the Suzuki-Miyaura coupling reaction. After the reaction was completed, the mixture was cooled to room temperature and 100 mL of water was added to quench the reaction. The organic phase was extracted with dichloromethane (100 mL × 3), washed three times with water (50 mL × 3), and dried with anhydrous Na2SO4. The crude product was purified by silica gel column chromatography with a gradient elution of petroleum ether / dichloromethane = 10:1 to 5:1 to obtain O-(2+2).

[0067] The following study uses the colorless and transparent crystal of the organic light-emitting macroring prepared in Example 1 as an example. The specific research methods and results are shown below: 1. Single-crystal analysis of colorless and transparent O-(2+2)furanyl organic luminescent macrocycle: Its single-crystal structure was determined by X-ray diffraction, and its single-crystal structure is as follows: Figure 12 As shown, the colorless and transparent crystals of the O-(2+2)furan-based organic light-emitting macrocycle are stacked in an orderly manner, forming a three-dimensional supramolecular organic framework with ordered pores in the solid state. Continuous channels exist within the O-(2+2)furan-based organic light-emitting macrocycle and between molecules, allowing for localized stress accumulation within the crystal, which is then released as mechanical work. The O-(2+2)furan-based organic light-emitting macrocycle is saddle-shaped, with Z-shaped molecular stacking, laying the foundation for subsequent molecular rearrangement and achieving the dynamic response of the colorless and transparent crystals of the O-(2+2)furan-based organic light-emitting macrocycle.

[0068] 2. Photomechanical response test of colorless transparent crystals of O-(2+2)furanyl organic luminescent macrocycles: Under a fluorescence microscope, colorless transparent crystals of O-(2+2) organic light-emitting macrocycles were irradiated with UV light, resulting in crystal elongation. Bright-field and dark-field images of the O-(2+2) organic light-emitting macrocycle crystals before and after UV irradiation show that the crystals elongated after UV irradiation. Before UV irradiation, the crystal length was 301.13 μm, and after UV irradiation, the crystal length was 331.04 μm, a change of approximately 10%. UV irradiation stimulated a diarylethene (DAE) response in the colorless transparent crystals of O-(2+2) organic light-emitting macrocycles, causing the crystal to change from racemic to mesotropic, undergoing a stereochemical configurational transformation and molecular rearrangement, resulting in a photomechanical response—crystal elongation. The crystals after UV irradiation are shown in the image below. Figure 13 As shown.

[0069] 3. Single-crystal analysis of the photomechanical response of a colorless, transparent crystal of an O-(2+2)furanyl organic luminescent macrocycle: Because the lattice order, size / morphology effectiveness, and structural stability of a crystal are all affected after photomechanical response, the diffraction signal changes from "clear, indexable, and constrained" to "diffuse, mixed, and disordered," ultimately making it impossible to determine the crystal structure through diffraction data. We used a solvent method: O⁻(2+2) (0.01 mmol) was added to a 4 mL reagent bottle, followed by 2 mL of toluene solvent. The 4 mL bottle was then placed inside a 50 mL reagent bottle, and 5 mL of methanol solvent was added. A 30 W UV lamp was used to irradiate the sample for 100 s at a distance of 20 cm from the reagent bottle. The sample was then stored in a 5°C incubator in the dark. After 14 days, a colorless and transparent crystal was obtained, and its single-crystal structure was determined by X-ray diffraction. The single-crystal structure is shown below. Figure 14 As shown, the colorless and transparent crystals of O-(2+2)furanyl organic light-emitting macrocycles are stacked in an orderly manner. The O-(2+2)furanyl organic light-emitting macrocycles are neatly arranged in the solid state to form a three-dimensional supramolecular organic framework with ordered pores. There are continuous channels in the inner cavity of the O-(2+2)furanyl organic light-emitting macrocycles and between molecules. The crystal changes from exocycly to mesocycly, undergoing a configurational transformation in stereochemistry and molecular rearrangement.

[0070] In short, through rational design and synthesis, a novel O-(2+2) intelligent molecular macrocycle was obtained by conjugating a dibenzofuran compound as the photoelectric unit and a diarylethene compound as the intelligent unit. Colorless and transparent crystals of the O-(2+2) furan-based organic luminescent macrocycle were obtained by slow evaporation. Upon UV irradiation, the crystals underwent a stereochemical configuration transformation from racemic to meso-rhythmic, resulting in crystal elongation. Figure 15 As shown.

[0071] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, it is intended to include any modifications and variations that fall within the scope of the claims and their equivalents.

Claims

1. A colorless and transparent crystal of an organic light-emitting macroring, characterized in that, In the colorless, transparent crystal of the organic light-emitting macroring, the structural formula of the organic light-emitting macroring is: .

2. A method for preparing a colorless and transparent crystal of an organic light-emitting macroring as described in claim 1, characterized in that, Includes the following steps: Using DAE and 2,8-dibromodibenzofuran as reactants, the reactants, palladium catalyst, phase transfer catalyst, ligand and inorganic base were dissolved in a solvent and subjected to a Suzuki-Miyaura coupling reaction under a protective gas atmosphere, followed by crystallization to prepare colorless and transparent organic luminescent macrocyclic crystals. Among them, DAE is 2,2'-(((perfluorocyclopent-1-en-1,2-diyl)bis(5-methylthiophene-4,2-diyl))bis(4,1-phenylene))bis(4,4,5,5-tetramethyl-1,3,2-dioxaborane).

3. The method for preparing colorless and transparent crystals of organic light-emitting macrorings according to claim 2, characterized in that, The molar ratio of DAE to 2,8-dibromodibenzofuran is 1:0.95~1.05, the molar ratio of DAE to palladium catalyst is 1.25:0.1~0.3, the molar ratio of DTE to phase transfer catalyst is 1.25:0.2~0.5, the molar ratio of DAE to ligand is 1.25:0.2~0.5, and the molar ratio of DAE to inorganic base is 1.25:20~50.

4. The method for preparing colorless and transparent crystals of organic light-emitting macrorings according to claim 2, characterized in that, The conditions for the Suzuki−Miyaura coupling reaction are: reaction at 75℃~85℃ for 5~7 days.

5. The method for preparing colorless and transparent crystals of organic light-emitting macrorings according to claim 2, characterized in that, The phase transfer catalyst is selected from tetrabutylammonium bromide, tetrabutylammonium chloride, tetrabutylammonium hydrogen sulfate, or hexadecyltrimethylammonium bromide.

6. The method for preparing colorless and transparent crystals of organic light-emitting macrorings according to claim 2, characterized in that, The ligands are selected from 2-dicyclohexylphosphine-2'-methylbiphenyl, 2-dicyclohexylphosphine-2',4',6'-triisopropylbiphenyl, 1,1'-bis(diphenylphosphine)ferrocene, or tricyclohexylphosphine.

7. The method for preparing colorless and transparent crystals of organic light-emitting macrorings according to claim 2, characterized in that, The solvent consists of toluene and water in a volume ratio of 13 to 15:

2.

8. The method for preparing colorless and transparent crystals of organic light-emitting macrorings according to claim 2, characterized in that, DAE is prepared according to the following steps: 2-methyl-3-thiophene boric acid was prepared by boron esterification of 3-bromo-2-methylthiophene with triisopropyl borate in the liquid phase under a nitrogen atmosphere and in the presence of n-butyllithium. In a nitrogen atmosphere, and in the presence of palladium catalyst, tricyclohexylphosphine, and cesium fluoride, 2-methyl-3-thiopheneboronic acid and 1,2-dichloroperfluorocyclopentene were subjected to a bis-Suzuki coupling reaction in the liquid phase to prepare 3,3′-(3,3,4,4,5,5-hexafluoro-1-cyclopenten-1,2-diyl)bis[2-methylthiophene]. Under a nitrogen atmosphere, in the presence of a palladium catalyst, ligand 2,2'-bipyridine, and inorganic base Ag2CO3, 3,3′-(3,3,4,4,5,5-hexafluoro-1-cyclopenten-1,2-diyl)bis[2-methylthiophene] was subjected to a bisCH arylation reaction with p-bromoiodobenzene to prepare 3,3′-(perfluorocyclopenten-1-en-1,2-diyl)bis(5-(4-bromophenyl)-2-methylthiophene); DAE was prepared by diboron esterification of 3,3'-(perfluorocyclopent-1-en-1,2-diyl)bis(5-(4-bromophenyl)-2-methylthiophene) with pinacol diboron under a nitrogen atmosphere in the presence of a palladium catalyst and the inorganic base potassium acetate.

9. The application of the colorless and transparent crystal of the organic light-emitting macroring as described in claim 1 in the preparation of photomechanical responsive materials.

10. The application of the colorless and transparent crystal of the organic light-emitting macroring according to claim 9 in the preparation of photomechanical responsive materials, characterized in that, The application method is as follows: by irradiating the colorless and transparent crystal of the organic light-emitting macroring with UV light, the colorless and transparent crystal of the organic light-emitting macroring changes from exocytic to meocytic, undergoing a configuration transformation in stereochemistry, and realizing photomechanical response—crystal elongation.

Images