Self-crosslinking organic electro-optic molecular glass materials and applications

Abstract

The application provides a self-crosslinking organic electro-optic molecular glass material and application. The self-crosslinking organic electro-optic molecular glass material of the application introduces two different functional groups on a bridge and a donor respectively, the bridge being a 4-(diethylamino)salicylaldehyde donor, an isofuroxan electronic bridge and a CF3-TCF electronic acceptor chromophore, a chromophore molecule with a single-chromophore self-crosslinking function is synthesized, through a D-A crosslinking reaction between the functional groups, a high-chromophore-loaded nonlinear optical material with high electro-optic coefficient and high thermal stability is prepared without a small molecule or polymer crosslinking agent.

Description

Technical Field

[0001] This invention relates to the field of organic electro-optic materials technology, and in particular to a self-crosslinked organic electro-optic molecular glass material and its applications. Background Technology

[0002] With the rapid development of information technology, the demand for new optical fiber communication devices with low power consumption, ultra-high speed, and large bandwidth is increasing daily. The ability to fabricate high-performance electro-optic materials is crucial to the application of electro-optic technology. Compared with traditional inorganic materials, organic electro-optic materials have faster response times and lower dielectric constants, thus exhibiting higher modulation bandwidth and efficiency. Furthermore, organic electro-optic materials demonstrate superior processing performance at both the molecular and material processing levels, sparking a surge of research interest among scholars.

[0003] Chromophores are the core source of electro-optic effects in organic nonlinear optical materials. Designing and synthesizing chromophores with ultra-high first-order hyperpolarizability (β), excellent photothermal stability, and good optical transparency has always been a research goal for scholars in the field of organic nonlinear optics. In addition, to realize the commercial application of organic electro-optic (OEO) materials and devices, organic electro-optic materials must withstand harsh thermal and environmental conditions during manufacturing and operation, and ultimately exhibit excellent electro-optic effects and stability.

[0004] In the early stages of polymer material research, chromophores were physically doped into polymers (such as polymethyl acrylate or amorphous carbonate) at relatively low concentrations. The thermal stability of composite OEO materials depended on the glass transition temperature (Tg) of the host polymer. Typically, this system exhibited a low electro-optic coefficient (r33) value, and chromophores were prone to aggregation due to dipole interactions, resulting in poor long-term stability. To overcome these shortcomings, side-chain polymers were developed to prevent chromophore separation from the polymer matrix. However, the reactions used for side-chain functionalization often produce byproducts or residual trace impurity ions, significantly attenuating the effective polarization electric field and causing DC bias drift during device operation. Furthermore, side-chain polymers also suffer from low chromophore concentration and low r33 values.

[0005] In view of this, the present invention is proposed. Summary of the Invention

[0006] The purpose of this invention is to provide a self-crosslinked organic electro-optic molecular glass material and its application, which has a high electro-optic coefficient and thermal stability.

[0007] This invention provides a self-crosslinked organic electro-optic molecular glass material, the structural formula of which is as follows:

[0008]

[0009] Wherein, R and R' are independently selected from one of the following structures:

[0010] , , , , The wavy line represents the connection point.

[0011] More specifically, the structural formula of the self-crosslinked organic electro-optic molecular glass material of the present invention is one of the following:

[0012] (i.e., chromophore A1),

[0013] (i.e., chromophore A2),

[0014] (i.e., chromophore A3).

[0015] The preparation method of the self-crosslinked organic electro-optic molecular glass material of the present invention has the following synthetic route:

[0016]

[0017] R and R' are independently selected from one of the following structures:

[0018] , , , , The wavy line represents the connection point.

[0019] In this invention, the preparation method of compound 1 includes: mixing 4-(diethylamino)salicylaldehyde with potassium carbonate, adding DMF and bromosilane to the mixture under argon protection to carry out the reaction; after the reaction, extracting with ethyl acetate, and then drying, filtering, and chromatographically separating the organic phase to obtain compound 1. Specifically, the molar ratio between 4-(diethylamino)salicylaldehyde, potassium carbonate, and bromosilane can be 1:(1.8-2.2):(1.8-2.2); the reaction temperature can be 85-95℃, and the reaction time can be 8-16h; the eluent used for chromatographic separation can be a mixed solvent of EA and PE, wherein the volume ratio of EA to PE in the mixed solvent is 1:(4-10).

[0020] The preparation method of compound 2 includes: reacting a methanol solution of compound 1 with dilute hydrochloric acid; removing excess hydrochloric acid with a saturated KHCO3 aqueous solution after the reaction, evaporating the methanol solvent, extracting with ethyl acetate, and then drying and chromatographically separating the organic phase to obtain compound 2. Specifically, the concentration of dilute hydrochloric acid is 0.8-1.2M; the volume ratio of compound 1 to dilute hydrochloric acid is 1g:(5-8)mL; the reaction temperature can be room temperature, the reaction time can be 3-4h, and the reaction can be carried out under stirring; the eluent used for chromatographic separation can be a mixed solvent of EA and PE, in which the volume ratio of EA to PE in the mixed solvent is 1:4 to 2:1.

[0021] The preparation method of compound 3 includes: mixing pyridine 4-methylbenzenesulfonic acid (PPTS) and p-methylbenzenesulfonic acid monohydrate, dissolving them in THF under argon protection, then adding compounds 2 and 3,4-dihydro-2H-pyran (DHP) for reaction; after the reaction, THF is first evaporated to dryness, then extracted with ethyl acetate, and after drying and chromatographic separation, compound 3 is obtained. Specifically, the molar ratio of pyridine 4-methylbenzenesulfonic acid, p-methylbenzenesulfonic acid monohydrate, and compounds 2 and 3,4-dihydro-2H-pyran is 1:(0.8-1.2):(18-22):(20-30); the reaction temperature can be room temperature, and the reaction time can be 2-4 h; the eluent used for chromatographic separation can be a mixed solvent of EA and PE, and the volume ratio of EA to PE in the mixed solvent is 1:(4-10).

[0022] The preparation method of compound 4 includes: dissolving sodium metal in ethanol under argon protection, followed by adding 2-mercaptoethanol, isoflurane bridge, and compound 3 for reaction; after the reaction, extraction with ethyl acetate, followed by drying and chromatographic separation of the organic phase to obtain compound 4. Specifically, the molar ratio between sodium metal, 2-mercaptoethanol, isoflurane bridge, and compound 3 is 1:(0.8-1.2):(2-3):(0.8-1.2); the reaction temperature can be 60-70℃, and the reaction time is 8-16h; the eluent used for chromatographic separation can be a mixed solvent of EA and PE, in which the volume ratio of EA to PE is 1:(3-10).

[0023] The preparation method of compound 5 includes: reacting imidazole, compound 4, and tert-butyldiphenylchlorosilane under argon protection; after the reaction, extraction with ethyl acetate, followed by drying and chromatographic separation of the organic phase to obtain compound 5. Specifically, the molar ratio of imidazole, compound 4, and tert-butyldiphenylchlorosilane is 1:(0.3-0.5):(0.8-1.2); the reaction temperature can be room temperature, and the reaction time is 2-4 h; the eluent used for chromatographic separation can be a mixed solvent of EA and PE, in which the volume ratio of EA to PE is 1:(5-10).

[0024] The preparation method of compound 6 includes: adding THF to sodium hydride under argon protection, followed by dropwise addition of diethyl cyanomethyl phosphate, and adding compound 5 after the solution becomes clear; after the reaction, extraction is performed with ethyl acetate, followed by drying and chromatographic separation of the organic phase to obtain compound 6. Specifically, the molar ratio of sodium hydride, diethyl cyanomethyl phosphate and compound 5 is 1:(0.8-1.2):(0.2-0.3); the reaction temperature can be 60-75℃, and the reaction time can be 8-16h; the eluent used for chromatographic separation can be a mixed solvent of EA and PE, in which the volume ratio of EA to PE in the mixed solvent is 1:(8-10).

[0025] The preparation method of compound 7 includes: dissolving compound 6 in DCM under argon protection, freezing, and then slowly adding diisobutylaluminum hydride for a low-temperature reaction. The reaction is then quenched by heating, followed by extraction, drying, and chromatographic separation of the reaction solution to obtain compound 7. Specifically, the molar ratio of compound 6 to diisobutylaluminum hydride can be 1:(2-3); the low-temperature reaction temperature can be -75℃ to -80℃, and the reaction time can be 3-5 h; quenching is performed by heating to room temperature, which includes: pre-quenching with a small amount of dichloride, followed by quenching with sufficient water; the eluent used for chromatographic separation can be a mixed solvent of EA and PE, where the volume ratio of EA to PE in the mixed solvent is 1:(6-10).

[0026] The preparation method of compound 8 includes: reacting compound 7 with tetraisobutylammonium fluoride; after the reaction, extraction with ethyl acetate, followed by drying and chromatographic separation of the organic phase to obtain compound 8. Specifically, the molar ratio of compound 7 to tetraisobutylammonium fluoride is 1:(1.8-2.2); the reaction temperature can be room temperature, and the reaction time can be 1-3 h; the eluent used for chromatographic separation can be a mixed solvent of EA and PE, in which the volume ratio of EA to PE in the mixed solvent is 1:(1-6).

[0027] The preparation method of compound 9 includes: mixing acrylate, maleimide or azide with DMAP and EDCI; adding DCM to the mixture under argon protection and stirring until the solution becomes clear; then adding compound 8 to react; after the reaction, extracting the organic phase with dichloromethane; drying and chromatographically separating the organic phase to obtain compound 9. Specifically, the molar ratio between acrylate, DMAP and EDCI is 1:(0.08-0.12):(0.8-1.2); the reaction is first carried out at 0-5℃ for 1-3 h, and then at 35-45℃ for 8-16 h; the eluent used for chromatographic separation can be a mixed solvent of EA and PE, in which the volume ratio of EA to PE in the mixed solvent is 1:(5-15).

[0028] The preparation method of compound 10 includes: reacting compound 9 with dilute hydrochloric acid; extracting and separating by column chromatography after the reaction to obtain compound 10. Specifically, the concentration of dilute hydrochloric acid is 0.8-1.2M; the volume ratio of compound 1 to dilute hydrochloric acid is 1g:(5-8)mL; the reaction temperature can be room temperature, the reaction time can be 1-3h, and the reaction can be carried out under stirring conditions; the eluent used for chromatographic separation can be a mixed solvent of EA and PE, and the volume ratio of EA to PE in the mixed solvent is 1:(3-10).

[0029] The preparation method of compound 11 includes: mixing 9-anthrapropionic acid, DMAP, and EDCI, adding DCM under argon protection and stirring until the solution becomes clear, then adding compound 10 to react; after the reaction, extracting the organic phase with dichloromethane, drying the organic phase after extraction, and separating it chromatographically to obtain compound 11. Specifically, the molar ratio between 9-anthrapropionic acid, DMAP, EDCI, and compound 10 is 1:(0.8-1.2):(0.8-1.2):(0.4-0.6); the reaction is first carried out at 0-5℃ for 1-3 h, and then at 35-45℃ for 8-16 h; the eluent used for chromatographic separation can be a mixed solvent of EA and PE, in which the volume ratio of EA to PE in the mixed solvent is 1:(5-15).

[0030] The preparation method of compound 12 includes: reacting compound 11 with CF3-TCF under argon protection, followed by rotary evaporation, column chromatography, and drying to obtain compound 12. Specifically, the molar ratio of compound 11 to CF3-TCF is 1:(0.8-1.2); the reaction temperature can be 35-45℃, and the reaction time can be 2-4 h; the eluent used for chromatographic separation can be a mixed solvent of EA and PE, in which the volume ratio of EA to PE is 1:(3-10).

[0031] The present invention also provides the application of the above-mentioned self-crosslinked organic electro-optic molecular glass material or the self-crosslinked organic electro-optic molecular glass material prepared according to the above preparation method in the preparation of organic electro-optic materials or devices.

[0032] This invention addresses current technical problems by proposing an organic electro-optic molecular glass material capable of self-crosslinking between unit chromophore molecules. Two different functionalized groups are introduced onto the bridge and donor of a chromophore using 4-(diethylamino)salicylaldehyde as a donor and isoflurone as an electron bridge, and CF3-TCF as an electron acceptor, respectively, synthesizing chromophore molecules with single-chromophore self-crosslinking functionality. Through the DA crosslinking reaction between functionalized groups, a high-chromophore-loaded nonlinear optical material with high electro-optic coefficient and high thermal stability is prepared without the need for small molecule or polymer crosslinking agents. Since the self-crosslinking between chromophore molecules does not require inactive binders, the concentration of active groups in the organic electro-optic molecular glass material can be maximized without leaving residual impurities. Simultaneously, self-crosslinking leads to better thermal stability; during polarization, a bonded three-dimensional covalent network is formed to restrict the movement of chromophore molecules, significantly increasing the material's Tg. Compared to existing multi-component systems, it offers significant advantages such as more uniform film formation and relatively simpler film preparation. Attached Figure Description

[0033] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0034] Figure 1 TGA curves of chromophores A1, A2, and A3 in Examples 1-3;

[0035] Figure 2 The differential thermal scanning curve of chromophore A1 in Example 1;

[0036] Figure 3 The differential thermal scanning curve of chromophore A2 in Example 2;

[0037] Figure 4 The differential thermal scanning curve of chromophore A3 in Example 3;

[0038] Figure 5 The UV-Vis absorption spectra of chromophore A1 in seven solvents in Example 1 are shown.

[0039] Figure 6 The UV-Vis absorption spectra of chromophore A2 in seven solvents in Example 2 are shown.

[0040] Figure 7 The UV-Vis absorption spectra of chromophore A3 in seven solvents in Example 3 are shown.

[0041] Figure 8 The UV-Vis absorption spectra of solid films with chromophores A1, A2, and A3 before and after crosslinking in Examples 1-3 are shown.

[0042] Figure 9 The above are the charge distribution diagrams of ground-state and excited-state states of chromophores A1, A2, and A3 in Examples 1-3. Detailed Implementation

[0043] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0044] It should be noted that the terminology used herein is for the purpose of describing particular implementations only and is not intended to limit the exemplary implementations according to this application. As used herein, the singular form includes the plural form unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this description, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0045] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0046] Example 1

[0047] The structural formula of the self-crosslinked organic electro-optic molecular glass material (referred to as chromophore A1) in this embodiment is as follows:

[0048]

[0049] The preparation steps of the self-crosslinked organic electro-optic molecular glass material in this embodiment are as follows:

[0050] (1) Synthesis of Compound 1

[0051] Weighed 4-(diethylamino)salicylaldehyde (15 g, 77.6 mmol) and dried potassium carbonate (21.5 g, 155.2 mmol) were added to a two-necked flask, and the mixture was protected with argon gas. 90 mL of DMF and bromosilane (37.13 g, 155.2 mmol) were then added to the flask, and the mixture was stirred thoroughly. The reaction solution was gradually heated to 90 °C and refluxed overnight. After the reaction was complete, the reaction solution was extracted with ethyl acetate. Anhydrous MgSO4 was added to the organic phase for drying. After filtering off the desiccant, the residue was separated by column chromatography (eluent volume composition EA:PE = 1:7). The solvent was evaporated to dryness, yielding a yellow oily substance (compound 1) with a yield of 92%.

[0052] (2) Synthesis of compound 2

[0053] Compound 1 (23.0 g, 71.4 mmol) was dissolved in MeOH and added to a single-necked reaction flask. Dilute HCl (1 M, 142.8 mL) was then slowly added, and the mixture was stirred at room temperature for 4 h. After the reaction was complete, excess hydrochloric acid was removed with saturated KHCO3 aqueous solution, the MeOH solvent was evaporated to dryness, and the mixture was extracted with ethyl acetate. The organic phase was dried over anhydrous magnesium sulfate, and finally separated by column chromatography (EA:PE = 1:1) to give a yellow solid (compound 2) in 89% yield.

[0054] (3) Synthesis of compound 3

[0055] 4-Pyridine 4-methylbenzenesulfonic acid (PPTS) (0.79 g, 3.2 mmol) and p-toluenesulfonic acid monohydrate (0.61 g, 3.2 mmol) were added to a two-necked flask and protected with argon gas. A small amount of THF solvent was then injected to dissolve the compound. Next, the dissolved compound 2 (15.1 g, 63.5 mmol) and 3,4-dihydro-2H-pyran (DHP) (6.4 g, 76.4 mmol) were added sequentially to the flask, and the reaction was allowed to proceed at room temperature for 3 h. After the reaction was complete, the THF was evaporated to dryness, followed by extraction with ethyl acetate, and finally drying with anhydrous MgSO4. The mixture was then separated by column chromatography (EA:PE = 1:7) to obtain a yellow oil (compound 3) in 78% yield.

[0056] (4) Synthesis of compound 4

[0057] Under ice bath and argon atmosphere, sodium metal (1.14 g, 49.8 mmol) was added to a two-necked flask, and ethanol (50 mL) was injected to dissolve the sodium metal. After complete dissolution, 2-mercaptoethanol (3.9 g, 49.8 mmol) was added. After 20 min, isoflurane oxide bridge (19.17 g, 124.5 mmol) was injected. The color deepened and stabilized. The ice bath was removed, and after another 1 h, compound 3 (16.0 g, 49.8 mmol) was added. The temperature was gradually raised to 65 °C and refluxed overnight. After compound 3 reacted completely, the reaction was stopped. The reaction solution was evaporated to dryness and extracted with ethyl acetate. Finally, the organic phase was dried over anhydrous MgSO4 and separated by column chromatography (EA:PE = 1:6) to give a red solid (i.e., compound 4), with a yield of 53%.

[0058] (5) Synthesis of compound 5

[0059] Imidazole (4.5 g, 66.0 mmol) was added to a two-necked flask. Under argon protection, compound 4 (13.7 g, 26.4 mmol) dissolved in DMF (90 mL) and tert-butyldiphenylchlorosilane (18.1 g, 66.0 mmol) were injected, and the reaction was carried out at room temperature for 3 h. After the reaction was complete, the mixture was extracted with ethyl acetate, and the organic phase was dried over anhydrous MgSO4 and purified by column chromatography (EA:PE = 1:7) to give a red product (compound 5) in 78% yield.

[0060] (6) Synthesis of Compound 6

[0061] Sodium hydride (60%, 3.3 g, 82.6 mmol) was added to a two-necked flask. Under argon protection, an appropriate amount of THF (120 mL) was injected, followed by dropwise addition of diethyl cyanomethyl phosphate (14.6 g, 82.6 mmol). After the solution became clear, compound 5 (15.6 g, 20.6 mmol) dissolved in THF (50 mL) was injected, and the mixture was gradually heated to 68 °C and refluxed overnight. After most of compound 5 had reacted, the reaction solution was collected, evaporated to dryness, and extracted with ethyl acetate. The organic phase was dried over anhydrous MgSO4 and purified by column chromatography (EA:PE = 1:9) to give a red solid (compound 6) in 75% yield.

[0062] (7) Synthesis of compound 7

[0063] Under argon protection, compound 6 (12.0 g, 15.5 mmol) was dissolved in DCM (30 mL) and injected into a double-necked flask. The mixture was frozen to -78 °C, and diisobutylaluminum hydride (1.0 M, 38.8 mL, 38.8 mmol) was slowly added. The reaction was carried out at -78 °C for 4 h. Before warming to room temperature, a small amount of dichloroisocyanuric acid (15 mL) was added for pre-quenching, followed by sufficient water for quenching. A precipitate formed. The precipitate was filtered, washed, extracted, dried, and purified by column chromatography (EA:PE = 1:8) to obtain a deep red solid product (compound 7) with a yield of 81%. (8) Synthesis of compound 8

[0064] Under argon protection, compound 7 (9.8 g, 12.6 mmol) was dissolved in THF (30 mL) and injected into a double-necked flask. Tetraisobutylammonium fluoride (1.0 M, 25.2 mL, 25.2 mmol) was added, and the mixture was reacted at room temperature for 2 h. After the reaction was complete, THF was removed by rotary evaporation, and the reactants were extracted with ethyl acetate. The organic phase was dried over anhydrous MgSO4 and purified by column chromatography (EA:PE = 1:3) to give 7.6 g of dark red solid product (i.e., compound 8), with a yield of 90%. (9) Synthesis of compound 9a

[0065] Acrylate (2.9 g, 11.0 mmol), DMAP (0.13 g, 1.1 mmol), and EDCI (2.1 g, 11.0 mmol) were added to a double-necked flask. Under argon protection, DCM (30 mL) was injected at 0 °C and stirred for 45 min until the solution became clear. Subsequently, compound 8 (3.0 g, 5.5 mmol) was dissolved in DCM and injected into the reaction solution. The reaction was continued at 0 °C for 2 h, then transferred to an oil bath and refluxed overnight at 40 °C. After the reaction was complete, the product was directly extracted with dichloromethane, and the organic phase was dried and separated by chromatographic column chromatography (EA:PE = 1:10) to give 3.5 g of product (i.e., compound 9a), with a yield of 81%.

[0066] (10) Synthesis of compound 10a

[0067] Compound 9a (3.5 g, 4.5 mmol) was dissolved in an appropriate amount of acetone, and dilute hydrochloric acid (1 M, 0.54 mL) was added. The mixture was stirred at room temperature for 2 h. After the reaction was complete, the solvent was removed, and the mixture was extracted. The organic phase was purified by column chromatography (EA:PE = 1:6) to give a deep red product (i.e., compound 10a) in 64% yield.

[0068] (11) Synthesis of compound 11a

[0069] 9-Anthrapropionic acid (1.4 g, 5.8 mmol), DMAP (0.07 g, 5.8 mmol), and EDCI (1.1 g, 5.8 mmol) were added to a double-necked flask, protected with argon gas, and DCM (20 mL) was injected at 0 °C. The mixture was stirred for 45 min until the solution became clear. Then, compound 10a (2.0 g, 2.9 mmol) was dissolved in DCM and injected into the reaction solution. The reaction was continued at 0 °C for 2 h, and then transferred to an oil bath and refluxed overnight at 40 °C. After the reaction was complete, the mixture was directly extracted with dichloromethane. The organic phase was dried and separated by chromatographic column chromatography (EA:PE = 1:10) to give 1.7 g of product (compound 11a), with a yield of 63%.

[0070] (12) Synthesis of chromophore A1

[0071] Under argon protection, compound 11a (0.8 g, 0.85 mmol) and CF3-TCF (0.85 mmol, 0.27 g) were added to a two-necked flask and dissolved in 6 mL of ethanol (1 mL of THF could be added if the solubility was poor). After complete dissolution, the mixture was reacted at 40 °C for 2 h until the starting material was completely exhausted. The mixture was then evaporated to dryness and separated by column chromatography (eluent EA:PE = 1:6). After drying, chromophore A1 (0.32 mmol, 0.44 g) was obtained, with a yield of 38%.

[0072] Example 2

[0073] The structural formula of the self-crosslinked organic electro-optic molecular glass material (referred to as chromophore A2) in this embodiment is as follows:

[0074]

[0075] The preparation steps of the self-crosslinked organic electro-optic molecular glass material in this embodiment are as follows:

[0076] (1)-(8) are the same as in Example 1.

[0077] (9) Synthesis of compound 9b

[0078] Maleimide (11.0 mmol), DMAP (0.13 g, 1.1 mmol), and EDCI (2.1 g, 11.0 mmol) were added to a double-necked flask. Under argon protection, DCM (30 mL) was injected at 0 °C and stirred for 45 min until the solution became clear. Subsequently, compound 8 (3.0 g, 5.5 mmol) was dissolved in DCM and injected into the reaction solution. The reaction was continued at 0 °C for 2 h, then transferred to an oil bath and refluxed overnight at 40 °C. After the reaction was complete, the mixture was directly extracted with dichloromethane, and the organic phase was dried and separated by column chromatography (EA:PE = 1:10) to give compound 9b in 76% yield.

[0079] (10) Synthesis of compound 10b

[0080] Compound 9b (4.5 mmol) was dissolved in an appropriate amount of acetone, and dilute hydrochloric acid (1 M, 0.54 mL) was added. The mixture was stirred at room temperature for 2 h. After the reaction was complete, the solvent was removed, and the mixture was extracted. The organic phase was purified by column chromatography (EA:PE = 1:6) to give compound 10b in 66% yield.

[0081] (11) Synthesis of compound 11b

[0082] 9-Anthrapropionic acid (1.4 g, 5.8 mmol), DMAP (0.07 g, 5.8 mmol), and EDCI (1.1 g, 5.8 mmol) were added to a double-necked flask, protected with argon gas, and DCM (20 mL) was injected at 0 °C. The mixture was stirred for 45 min until the solution became clear. Then, compound 10b (2.9 mmol) was dissolved in DCM and injected into the reaction solution. The reaction was continued at 0 °C for 2 h, and then transferred to an oil bath and refluxed overnight at 40 °C. After the reaction was complete, the mixture was directly extracted with dichloromethane, and the organic phase was dried and separated by chromatographic column chromatography (EA:PE = 1:10) to give compound 11b in 61% yield.

[0083] (12) Synthesis of chromophore A2

[0084] Under argon protection, compound 11b (0.85 mmol) and CF3-TCF (0.85 mmol, 0.27 g) were added to a two-necked flask and dissolved in 6 mL of ethanol (1 mL of THF could be added if the solubility was poor). After complete dissolution, the mixture was reacted at 40 °C for 2 h until the starting material was completely exhausted. The solution was then evaporated to dryness and directly separated by column chromatography (eluent EA:PE = 1:6). The chromophore A2 was obtained by drying, with a yield of 39%. Example 3

[0085] The structural formula of the self-crosslinked organic electro-optic molecular glass material (referred to as chromophore A3) in this embodiment is as follows:

[0086]

[0087] The preparation steps of the self-crosslinked organic electro-optic molecular glass material in this embodiment are as follows:

[0088] (1)-(8) are the same as in Example 1.

[0089] (9) Synthesis of compound 9c

[0090] Azide (11.0 mmol), DMAP (0.13 g, 1.1 mmol), and EDCI (2.1 g, 11.0 mmol) were added to a double-necked flask. Under argon protection, DCM (30 mL) was injected at 0 °C and stirred for 45 min until the solution became clear. Subsequently, compound 8 (3.0 g, 5.5 mmol) was dissolved in DCM and injected into the reaction solution. The reaction was continued at 0 °C for 2 h, and then transferred to an oil bath and refluxed overnight at 40 °C. After the reaction was complete, the mixture was directly extracted with dichloromethane. The organic phase was dried and separated by chromatographic column chromatography (EA:PE = 1:10) to give compound 9c in 63% yield. (10) Synthesis of compound 10c

[0091] Compound 9c (4.5 mmol) was dissolved in an appropriate amount of acetone, and dilute hydrochloric acid (1 M, 0.54 mL) was added. The mixture was stirred at room temperature for 2 h. After the reaction was complete, the solvent was removed, and the mixture was extracted. The organic phase was purified by column chromatography (EA:PE = 1:6) to give compound 10c in 67% yield.

[0092] (11) Synthesis of compound 11c

[0093] 9-Anthrapropionic acid (1.4 g, 5.8 mmol), DMAP (0.07 g, 5.8 mmol), and EDCI (1.1 g, 5.8 mmol) were added to a double-necked flask, protected with argon gas, and DCM (20 mL) was injected at 0 °C. The mixture was stirred for 45 min until the solution became clear. Then, compound 10c (2.9 mmol) was dissolved in DCM and injected into the reaction solution. The reaction was continued at 0 °C for 2 h, and then transferred to an oil bath and refluxed overnight at 40 °C. After the reaction was complete, the mixture was directly extracted with dichloromethane, and the organic phase was dried and separated by chromatographic column chromatography (EA:PE = 1:10) to obtain compound 11c with a yield of 73%. (12) Synthesis of chromophore A3

[0094] Under argon protection, compound 11c (0.85 mmol) and CF3-TCF (0.85 mmol, 0.27 g) were added to a two-necked flask and dissolved in 6 mL of ethanol (1 mL of THF could be added if the solubility was poor). After complete dissolution, the mixture was reacted at 40 °C for 2 h until the starting material was completely exhausted. The solution was then evaporated to dryness and directly separated by column chromatography (eluent EA:PE = 1:6). The chromophore A3 was obtained by drying, with a yield of 40%. Experimental Example

[0095] 1. Thermogravimetric analysis

[0096] The thermal decomposition properties of chromophores A1, A2, and A3 in Examples 1-3 were tested using thermogravimetric analysis (TGA). The experimental conditions were: under nitrogen atmosphere, with a heating rate of 10 °C / min. The thermal decomposition temperature curves are shown below. Figure 1 As shown.

[0097] The results show that the thermal decomposition temperatures Td (the temperature at which the weight of the sample material is reduced to 95% of its original value) of chromophores A1, A2, and A3 are 294℃, 265℃, and 262℃, respectively. These thermal decomposition temperatures are higher than those under general environmental and experimental process conditions, which is beneficial for material development and subsequent applications.

[0098] 2. Glass transition temperature Tg

[0099] Differential calorimetry analysis was performed on chromophores A1, A2, and A3 from Examples 1-3 to determine the glass transition temperature (Tg) of each chromophore. The results are as follows: Figures 2-4 As shown.

[0100] The results showed that the test conditions for chromophores A1, A2, and A3 before crosslinking were: heating from room temperature to 160℃, cooling from 160℃ to room temperature, and then heating to 200℃. The crosslinking procedure was based on the non-crosslinking heating and cooling procedure with an additional 60-minute holding period. The holding temperatures for A1, A2, and A3 were 160℃, 135℃, and 150℃, respectively. The heating rate was 10℃ / min and the cooling rate was 20℃ / min. The glass transition temperatures (TTs) of chromophores A1, A2, and A3 before crosslinking were 71℃, 127℃, and 66℃, respectively. After crosslinking, these TTs increased to 185℃, 165℃, and 158℃, respectively, showing a significant improvement. In other words, three high-Tg small-molecule thin-film electro-optic materials were obtained through mono-molecule self-crosslinking of chromophores. 3. Ultraviolet-Visible Absorption Spectroscopy

[0101] The UV-Vis absorption spectra of chromophores A1, A2, and A3 from Examples 1-3 in seven different polar solvents—acetone, dichloromethane, 1,4-dioxane, acetonitrile, toluene, chloroform, and tetrahydrofuran—were measured, and the results are as follows: Figures 5-7 As shown.

[0102] The results show that the three chromophores A1, A2, and A3 have almost identical π-π* absorption peaks. The absorption of the spectral curves of the three chromophores is mainly concentrated between 600 nm and 1000 nm. Near the working wavelength of the electro-optic material (1310 nm), the spectral absorption is almost negligible, indicating that the three chromophore materials do not absorb light energy or absorb almost no light energy during operation, thus avoiding optical loss. In addition, the solvation effects of chromophores A1, A2, and A3 are 159 nm, 151 nm, and 97 nm, respectively, which are much larger than the solvation effect (60 nm) of the common isoflurane chromophore (CLD chromophore). This indicates that these three chromophores have strong polarizability, which is especially important for cross-linked chromophores. In the fabrication of electro-optic materials, the polarization orientation process of cross-linked chromophores must precede the cross-linking process. Therefore, the polarization orientation speed of chromophore molecules should be as fast as possible, and the stronger the polarizability, the more beneficial it is to the increase in the proportion of chromophore molecules in the polarization process.

[0103] 4. Study on UV-Vis absorption spectra before and after self-crosslinking

[0104] The UV-Vis absorption spectra of the solid films prepared from chromophores A1, A2, and A3 in Examples 1-3 before and after self-crosslinking were studied to understand the self-crosslinking behavior of the chromophores in the solid films. The self-crosslinking conditions for the chromophores were as follows: A1 was gradually heated to 160°C under vacuum and held at that temperature for one hour for crosslinking; chromophores A2 and A3 were gradually heated under vacuum and held at 135°C and 150°C, respectively, for one hour for crosslinking. The UV-Vis absorption spectra are as follows: Figure 8 As shown.

[0105] The results showed that chromophores A1 and A2 exhibited a distinct anthracene characteristic peak below 400 nm, and the anthracene content decreased significantly after self-crosslinking, corresponding to a downward shift of the anthracene characteristic peak in the absorption spectrum. This indicates that chromophores A1 and A2 underwent a considerable degree of self-crosslinking, a fact further supported by the overall blue shift in the absorption spectrum. Chromophore A3, lacking anthracene groups, could only be assessed for potential self-crosslinking based on its blue shift in the spectrum. Furthermore, the absorption peak shapes of chromophores A1, A2, and A3 did not change significantly before and after self-crosslinking, indicating good thermal stability.

[0106] 5. Chromophore β value

[0107] Theoretical calculations were performed on chromophores A1, A2, and A3 from Examples 1-3. Using the Gaussian09 software package, the molecular structure of the chromophores was first optimized at the B3LYP level using the 6-31g(d) basis set, yielding the HOMO-LUMO diagrams, dipole moments (μ), and energy level differences (ΔE) for the three molecules. Then, the optimized structure diagrams were supercomputed to calculate the first-order hyperpolarizability, resulting in the β value. The results are summarized in Table 1.

[0108] Table 1. DFT theoretical calculations for chromophores A1, A2, and A3

[0109]

[0110] The energy level differences ΔE between chromophores A1, A2, and A3 are 1.982 eV, 1.988 eV, and 1.952 eV, respectively. The energy level differences between the three chromophores are very small, which corresponds to the similar red shift of the three chromophores in chloroform solvent in the UV absorption spectrum. Furthermore, the calculated β values ​​for the three chromophores are 1064.56 × 10⁻⁶. -30 esu, 1035.14×10 -30 esu, 1032.18×10 -30 The β values ​​are all quite close, indicating that different functionalized groups do not affect the overall conjugated structure of the molecule, resulting in similar β values. 6. Electron density distribution

[0111] After optimizing the molecular structures of chromophores A1, A2, and A3 in Examples 1-3, the electron density distribution maps of the frontier molecular orbitals were calculated, as shown below. Figure 9 As shown.

[0112] The results show that the electron density distribution along the chromophore donor, bridge, and acceptor is asymmetric. In the HOMO state, the electron cloud in the molecule is mainly concentrated on the π-electron bridge and the donor, with only a small portion on the acceptor. In the LOMO state, due to intramolecular charge transfer, the electron cloud density is mainly concentrated on the electron bridge and the acceptor.

[0113] 7. Maximum electro-optic coefficient

[0114] The maximum electro-optic coefficients of chromophores A1, A2, and A3 in Examples 1-3 were tested. To compare the efficiency of converting the microscopic hyperpolarizability of chromophores A1, A2, and A3 into macroscopic electro-optic properties, thin film devices were fabricated by coating organic electro-optic materials onto ITO and gold electrode layers, and the polarization properties and electro-optic coefficients of the chromophores were tested.

[0115] First, an electro-optic thin film was prepared using a spin-coating method. Specifically, chromophores A1, A2, and A3 were completely dissolved by sonication for 15 minutes using 1,1,2-trichloroethane as a solvent. The dissolved solution was then filtered to remove undissolved portions using a syringe with a 0.02 μm polytetrafluoroethylene (PTFE) filter. The resulting solution was then uniformly spin-coated onto a glass substrate using a spin coater. To minimize errors caused by multiple reflections during electro-optic coefficient testing, a highly transparent, low-refractive-index indium tin oxide (ITO) glass substrate was selected. Finally, the film was dried on a 60°C heating plate to remove residual solvent before electro-optic coefficient testing. Contact polarization was used to induce the ordered orientation of the chromophore molecules. The polarization temperature of the glass film is typically 5-10°C higher than Tg during polarization, but the crosslinking polarization temperature of this chromophore system increases progressively. Specific polarization temperature and time parameters were continuously optimized. Finally, the electro-optic properties of the small-molecule electro-optic thin film were measured using a simple reflection method. The specific test results are shown in Table 2.

[0116] Table 2 Polarization efficiency and electro-optic coefficient of electro-optic materials

[0117]

[0118] From Table 2 r 33 The relationship between the value and number density shows that the chromophore r 33 The difference is mainly due to the number density of chromophore molecules. To compare the electro-optic coefficients and polarization efficiency before and after chromophore crosslinking, we also tested the electro-optic properties of A1, A2, and A3 after crosslinking. The electro-optic coefficients after crosslinking were 253 pm / V, 273 pm / V, and 280 pm / V, respectively. Generally speaking, under the action of an electric field, only a small portion of pure chromophores undergo orientational alignment, which affects the electro-optic coefficient r. 33This is a valuable contribution. Especially for cross-linked systems, the cross-linking reaction of functionalized groups connects chromophore molecules into a three-dimensional network structure via covalent bonds, significantly restricting the movement of chromophore molecules in the film. Therefore, the cross-linking reaction does reduce the electro-optic coefficient to some extent. However, in chromophores A1, A2, and A3, the highest measured electro-optic coefficients after cross-linking increased by approximately 30 pm / V. This is because their highest electro-optic coefficients were obtained at different voltages; the polarization electric fields before and after cross-linking were 80 V / μm and 100 V / μm, respectively. Despite this, the increase in the highest electro-optic coefficient of the chromophore film material still benefits from the cross-linking process. The cross-linking reaction significantly improves the stability of the chromophore, effectively preventing current leakage and allowing it to withstand higher polarization voltages, thus achieving a higher electro-optic coefficient. Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A self-crosslinked organic electro-optic molecular glass material, characterized in that, Its structural formula is one of the following: ， ， 。 2. The application of the self-crosslinked organic electro-optic molecular glass material according to claim 1 in the preparation of organic electro-optic materials or devices.

Images