Organic nonlinear optical chromophore with high thermal stability as well as preparation method and application of organic nonlinear optical chromophore

Abstract

The invention relates to the technical field of organic second-order nonlinear optical materials, in particular to an organic nonlinear optical chromophore and a preparation method and application thereof. The compound of the organic nonlinear optical chromophore has the following structural formula: # imgabs0 #, the organic second-order nonlinear optical chromophore with the structural formula is self-formed into a film or doped into polycarbonate to prepare an organic electro-optical thin film material, and the organic electro-optical thin film material is polarized. The polarized thin film material can be used as a key core material of an electro-optical modulator.

Description

Technical Field

[0001] The invention relates to the technical field of organic second-order nonlinear optical materials, and in particular to an organic nonlinear optical chromophore with high thermal stability and a preparation method and application thereof. Background Art

[0002] With the development of the information age, the amount of information that needs to be processed has increased dramatically. Electronic processing technology faces technical bottlenecks due to its low frequency and high loss. Photonic technology has the advantages of small size, light weight, high frequency and anti-electromagnetic interference, which has become an inevitable trend of development. It has been widely used in high-tech fields such as optical communication, optical information processing, optical sensing technology, Internet of Things, electronic countermeasures, photonic computers, etc. Integrated optoelectronic devices such as electro-optic modulators, electro-optic switches, and electro-optic filters are the core components in photonic processing technology, and these components are made of second-order nonlinear optical (NLO) materials. At present, practical second-order nonlinear optical materials are mainly inorganic materials, but inorganic materials such as lithium niobate have limited electro-optic coefficients, which limits their wide application. People have found that organic second-order nonlinear optical materials have advantages that inorganic materials cannot match, such as high electro-optic coefficients (theoretical values ​​can reach more than 1000 pm / V), fast response speed (sub-picosecond or even picosecond), low dielectric constant, good processability and integration performance, etc., and are increasingly attracting people's attention. Since the magnitude of the nonlinear optical response of organic materials depends on the excellence of the nonlinear optical properties of the chromophore molecules therein, however, the chromophore molecules of general structure are dipole molecules. Due to the strong intermolecular interaction force in the polymer, their solubility in the polymer matrix is ​​low and they are easy to aggregate, resulting in low polarization efficiency and small electro-optic coefficient. At the same time, the chromophore molecules face the problem of poor thermal stability. These characteristics cannot meet the requirements of deviceization well.

[0003] Therefore, it is necessary to design and synthesize a material with both a large electro-optic coefficient (i.e., the first-order molecular hyperpolarizability (β) at the microscopic molecular level and an electro-optic coefficient (r 33 )) and high thermal stability of second-order nonlinear optical chromophore molecules has always been one of the most challenging topics.

[0004] In view of this, the present invention is proposed. Summary of the invention

[0005] In order to solve the above problems in the prior art, the present invention provides an organic nonlinear optical chromophore and a preparation method and application thereof.

[0006] Based on this, the present invention has the following technical solutions: In a first aspect, the present invention provides a compound having the structural formula shown below: ; in: R1 represents H, substituted or unsubstituted C1~C 20 Alkyl, substituted or unsubstituted benzyl, phenyl acyl, C1~C 20 Aliphatic acyl or C1~C 10 A silyl group, or a group consisting of any of the above groups; R2 represents H, substituted or unsubstituted C1~C 20 Alkyl, substituted or unsubstituted C1~C 20 Alkoxy, substituted or unsubstituted C1~C 20 alkylthio or silyloxy, or a group consisting of any of the above groups; R3 and R4 are each independently, identical or different and represent substituted or unsubstituted C1~C 20 Alkyl, substituted or unsubstituted C6~C 30 phenyl, or a group consisting of any of the above groups; When substituted, the substituent includes hydroxyl, halogen or aromatic heterocycle, the heteroatom includes one or more of nitrogen atom, sulfur atom and oxygen atom; the halogen includes fluorine and / or chlorine.

[0007] In the present invention, the compound has a D-π-A structure. Specifically, it uses aniline or its derivatives modified with substituted bisphenol fluorene groups as electron donors, substituted cyclic polyene structures as conjugated electron bridges, and tricyanodihydrofuran (TCF) or trifluoro-substituted tricyanodihydrofuran (CF3-TCF) as electron acceptors, and can obtain an organic second-order nonlinear optical chromophore with ultra-high first-order molecular hyperpolarizability (β value), large dipole moment, good solubility, good stability, good film-forming properties after doping with polymers, easy polarization, high macroscopic electro-optical coefficient, and easy deviceization.

[0008] Preferably, R1 represents H, substituted or unsubstituted C1~C5 alkyl, substituted or unsubstituted benzyl, phenyl acyl, C1~C 20 aliphatic acyl, silyl, or a group consisting of any of the above groups; when substituted, the substituent includes hydroxyl or fluorine; R2 represents a substituted or unsubstituted C1-C5 alkyl, a substituted or unsubstituted C1-C5 alkoxy, a substituted or unsubstituted C1-C5 alkylthio or silyl; when substituted, the substituent includes hydroxyl or fluorine; R3 and R4 are each independently, the same or different, substituted or unsubstituted C1-C5 alkyl, a substituted or unsubstituted C6-C 18 when substituted, the substituents include hydroxy or halogen; the halogen includes fluorine and / or chlorine.

[0009] More preferably, R1 represents a silyl group or a substituted or unsubstituted benzyl group; the silyl group includes a trimethylsilyl group, a tert-butyldimethylsilyl group or a dimethylphenylsilyl group; R2 represents a substituted or unsubstituted C1~C3 alkoxy group; R3 represents a methyl group or a trifluoromethyl group; R4 represents a substituted or unsubstituted C1~C3 alkyl group, a substituted or unsubstituted C6~C 12 when substituted, the substituents include hydroxy or fluorine.

[0010] In a second aspect, the present invention provides a method for preparing the compound, and its synthetic route is as follows: ; wherein, the groups represented by R1, R2, R3, R4 in the compounds involved in each step and the groups represented by R1, R2, R3, R4 in the obtained compound products are the same as those referred to above.

[0011] Preferably, the preparation method of the compound comprises: preparing : S1: The mixture was dissolved in redistilled tetrahydrofuran with p-toluenesulfonyl chloride, and triethylamine was added dropwise under nitrogen and ice bath conditions for 1 to 1.5 hours. The ice bath equipment was removed and the sealed system was allowed to react overnight at room temperature. After the reaction, the reaction solution was poured into deionized water, extracted with ethyl acetate, the organic phases were combined, and the combined organic phases were dried. The ethyl acetate was removed by rotary evaporation, and column chromatography was performed to obtain the obtained product. ; S2: The mixture is dissolved in redistilled N,N-dimethylformamide with 9-fluorene bisphenol and anhydrous potassium carbonate, and heated to 90-110 °C under nitrogen protection for 20-24 hours. After the reaction is completed, it is poured into deionized water to obtain an orange solution, which is extracted with ethyl acetate. The organic phases are combined and washed with a saturated sodium chloride solution. The organic phase is dried and then the organic solvent is removed by rotary evaporation. The organic phase is separated by column chromatography and dried to obtain ; Wherein, R2 in the compound involved in each step is the same as that indicated in claims 1 to 3.

[0012] In the present invention, those skilled in the art can synthesize according to the technical solutions disclosed in the prior art For example, you can refer to the following literature: WW Jin, PV Johnston, DL Elder, KT Manner, KE Garrett, W. Kaminsky, RM Xu, BH Robinson, LR Dalton, J. Mater. Chem. C 2016,4, 3119-3124. More preferably, in S1, The molar ratio with p-toluenesulfonyl chloride is 1:(2~4); and / or S2, , the molar ratio of 9-fluorene bisphenol and anhydrous potassium carbonate is 1:(4~6):(12~14).

[0013] Preferably, the method for preparing the compound further comprises: S3: and imidazole are dissolved in redistilled N,N-dimethylformamide, and the compound containing R1 is slowly added to the mixed solution under N2 protection, and the reaction is carried out at 20-30 °C; after the reaction is completed, it is poured into deionized water and extracted with n-hexane, the organic phase is washed with brine, the solvent is removed by rotary evaporation after drying, the residue is separated by column chromatography, and the obtained product is obtained after drying. ; S4: The tricyandihydrofuran electron acceptor was dissolved in anhydrous ethanol and refluxed at 80-100°C for 0.5-1 hour. After the reaction was completed, the mixture was cooled to 20-30°C, and the ethanol and water were removed by rotary evaporation. The mixture was separated by column chromatography and then dried to obtain ; Wherein, the groups represented by R2, R3, and R4 in the compounds involved in each step are the same as those indicated in claims 1 to 3, and R1 represents H, substituted or unsubstituted C1 to C 20 Alkyl, phenyl acyl, C1~C 20 Aliphatic acyl or C1~C 10 A silyl group, or a group consisting of any of the above groups.

[0014] More preferably, The molar ratio with imidazole is 1:(2~3); and / or The molar ratio with chlorosilane is 1:(2~3); and / or The molar ratio of tricyandihydrofuran electron acceptor is 1:(1~1.5).

[0015] Or, the preparation method of the compound further comprises: S3': The substituted or unsubstituted benzyl compound, potassium carbonate and potassium iodide are dissolved in anhydrous N,N-dimethylformamide, heated at 80-90 °C for 20-24 hours, and after the reaction is completed and cooled to room temperature, the product is poured into water, extracted with dichloromethane, and the organic phase is dried, the solvent is removed by rotary evaporation, and column chromatography is performed to obtain ; S4': The tricyandihydrofuran electron acceptor was dissolved in anhydrous ethanol, sealed and refluxed at 70-90 °C for 0.5-1 hour, and the solvent was removed by rotary evaporation after the reaction was completed. The product was separated by column chromatography and dried to obtain ; wherein R1' is a substituted or unsubstituted benzyl group.

[0016] More preferably, With a substituted or unsubstituted benzyl compound, potassium carbonate, and potassium iodide in a molar ratio of 1:2:2:(6-7); and / or, The molar ratio of tricyandihydrofuran electron acceptor is 1:(1~2).

[0017] In a third aspect, the present invention provides use of the above compound in an organic nonlinear optical chromophore.

[0018] In a fourth aspect, the present invention provides an organic nonlinear optical chromophore comprising the compound.

[0019] In a fifth aspect, the present invention provides the use of the compound in polarized self-forming film (chromophore accounts for 100%) or polarized polymer film.

[0020] In a sixth aspect, the present invention provides a polarized polymer film, which is mainly made of the compound.

[0021] Preferably, the polarized polymer film is mainly made of the compound and amorphous polycarbonate in a mass ratio of 1:1-100.

[0022] The electron donor, conjugated π electron bridge and electron acceptor used in the present invention can effectively improve the intramolecular electron transmission capacity after being combined together, and the rigid structure of the bisphenol fluorene can increase the steric effect and increase the molecular glass transition temperature Tg. Therefore, this type of structure can effectively increase the first-order molecular hyperpolarizability (β) of the chromophore molecule and effectively reduce the intermolecular interaction force. In addition, the application of the molecule in the modulator can effectively improve the thermal stability of the device.

[0023] The organic second-order nonlinear optical chromophore with a D-π-A structure of the present invention can be used to form a film by itself or be doped with amorphous polycarbonate (APC) to prepare a polarized organic film. The prepared polarized organic film is used as a material for preparing an electro-optical modulator to meet the device requirements.

[0024] Further preferably, the polarized polymer film is mainly made of the compound and amorphous polycarbonate in a mass ratio of 1:1-100.

[0025] In a seventh aspect, the present invention provides a material for an electro-optic modulator, which contains the polarized self-forming film (chromophore accounts for 100%) or the polarized polymer film.

[0026] The advantages of the present invention are: 1) Compared with the structure of traditional chromophores, the organic second-order nonlinear optical chromophore with D-π-A structure of the present invention uses an aniline group modified with substituted bisphenol fluorene as the electron donor, and two different types of substituted bisphenol fluorene are selected. This structure has greater steric hindrance, can effectively reduce the interaction force between molecules, improve polarization efficiency, and obtain a high electro-optic coefficient. In addition, the rigid planar structure of the fluorene ring is conducive to increasing the glass transition temperature of the chromophore molecule.

[0027] 2) Tricyandihydrofuran (TCF) or trifluoro-substituted tricyandihydrofuran (CF3-TCF) has a strong electron-withdrawing effect and can effectively improve the electro-optical properties of the chromophore as an electron acceptor. The high-performance organic second-order nonlinear optical chromophore compound with a D-π-A structure of the present invention can form a film by itself, or can be doped with polymers such as amorphous polycarbonate (APC) (mass ratio is 1:1 to 100) to prepare a polarized organic thin film.

[0028] 4) The electro-optic coefficient of organic second-order nonlinear optical chromophore compounds measured when they are self-filmed is higher than that measured when they are doped into polymers.

[0029] 5) The organic second-order nonlinear optical chromophore with a D-π-A structure of the present invention has simple synthesis steps and a high preparation yield. It has good solubility and high thermal stability in most organic solvents (such as acetone, chloroform, etc.), and can be widely used in the field of electro-optical materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0031] Figure 1 This is a test chart of the electro-optic coefficient stability of the BHG2 and JRD1 films provided by the present invention. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] Unless otherwise specified, the various raw materials used in the examples and comparative examples are commercially available conventional raw materials, and the technical means used are conventional means well known to those skilled in the art.

[0034] Example 1 The organic second-order nonlinear optical chromophore with a D-π-A structure as shown below was synthesized: The synthetic route is as follows: 1) The synthesis of compound 1 shown in formula 1 can be found in the literature (WW Jin, PV Johnston, DLElder, KT Manner, KE Garrett, W. Kaminsky, RM Xu, BH Robinson, LR Dalton, J. Mater. Chem. C 2016, 4, 3119-3124.) 2) Synthesis of compound 2 represented by formula 2 3.85 g (10 mmol) of compound 1, 5.30 g (30 mmol) of p-toluenesulfonyl chloride and 30 mL of redistilled tetrahydrofuran (THF) were added to a 50 ml glass three-necked flask. After dissolution, the reaction system was cooled to 0 °C with an ice bath under a nitrogen (N2) environment, and triethylamine was added dropwise. After the reaction was carried out for 1 hour, the ice bath was removed and the system was allowed to continue to react overnight at room temperature. After the reaction was completed, the mixture was poured into 50 mL of deionized water to terminate the reaction, extracted three times with ethyl acetate and the organic phase was collected. The p-toluenesulfonyl chloride that had not reacted completely was washed away with a 10% NaOH solution. The product was dried over anhydrous magnesium sulfate and rotary evaporated to obtain a red solid crude product, namely compound 2, with a yield of 80%.

[0035] 3) Synthesis of compound 3 shown in formula 3 In a 100 ml round-bottom flask, 1.386 g (2 mmol) of compound 2 obtained in step 2), 3.50 g (10 mmol) of fluorene-9-bisphenol, 1.40 g (26 mmol) of anhydrous potassium carbonate and 50 mL of redistilled N,N-dimethylformamide (DMF) were added; the mixture was heated to 100 °C under nitrogen protection for 24 hours. After the reaction was completed, the mixture was poured into 200 mL of deionized water to obtain an orange solution, which was extracted three times with ethyl acetate. The organic phases were combined and washed with saturated sodium chloride solution. The organic phases were dried with anhydrous magnesium sulfate and the organic solvent was removed by rotary evaporation. The residue was separated by column chromatography (with 200-300 mesh silica gel as the stationary phase and a mixture of n-hexane and ethyl acetate as the mobile phase, wherein the volume ratio of n-hexane to ethyl acetate was 1:20). After drying, a red solid was obtained, which was compound 3 with a yield of 52%.

[0036] MS(MALDI-TOF), m / z:1049.47 (M+); 1 H NMR (400 MHz, CDCl3) δ 10.05 (d, J= 8.3 Hz, 1H), 7.96 (s, 1H), 7.71 (d, J = 7.4 Hz, 4H), 7.36–7.28 (m, 10H),7.25–7.20 (m, 5H), 7.04 (dd, J = 20.2, 7.9 Hz, 8H), 6.67 (d, J = 8.4 Hz,11H), 6.31 (d, J = 8.2 Hz, 1H), 4.07 (s, 4H), 3.79 (s, 4H), 3.61 (s, 3H), 2.71 (s, 2H), 2.37 (s, 2H), 1.04 (s, 6H). 4) Synthesis of compound 4 represented by formula 4 10.50 g (10 mmol) of compound 3 and 1.66 g (24 mmol) of imidazole were dissolved in 20 mL of DMF. Under N2 protection, 3.68 g (24 mmol) of tert-butyldimethylsilyl chloride was slowly added to the mixed solution. After stirring at room temperature for 3 hours, the reaction system was poured into 100 mL of water. The organic phase was extracted with n-hexane, washed with brine, dried over anhydrous magnesium sulfate, and the solvent was removed by rotary evaporation. The crude product was separated by column chromatography (using 200-300 mesh silica gel as the stationary phase and a mixture of ethyl acetate and n-hexane as the mobile phase for gradient elution, wherein the volume ratio of ethyl acetate to n-hexane was 1:15 and gradually increased to 1:10). After drying, a red oily liquid was obtained, which was compound 4 with a yield of 93.1%.

[0037] MS(MALDI-TOF), m / z:1278.6458 (M+); 1 H NMR (400 MHz, CDCl3) δ 10.08 (d, J = 8.3 Hz, 1H), 7.71 (d, J = 7.5 Hz, 4H), 7.33 (dt, J = 14.8, 5.4 Hz, 10H), 7.21(t, J = 7.3 Hz, 5H), 7.05 (dd, J = 13.2, 8.7 Hz, 8H), 6.67 (dd, J = 8.5, 4.9 Hz,11H), 6.33 (d, J = 8.3 Hz, 1H), 4.05 (t, J = 5.6 Hz, 4H), 3.78 (t, J = 5.5 Hz, 4H), 3.64 (s, 3H), 2.72 (s, 2H), 2.37 (s, 2H), 1.05 (s, 6H), 0.95 (s, 18H), 0.15 (s, 12H). 5) Synthesis of organic second-order nonlinear optical chromophore with D-π-A structure (shown as BHG1 in the formula) 1.2 mmol of compound 4 obtained in step 4 and 0.28 g (1.4 mmol) of tricyanodihydrofuran (TCF) were dissolved in 20 mL of ultra-dry ethanol and then refluxed at 80 °C for 0.5 h. After the reaction was completed, the solvent was removed by rotary evaporation, and the crude product was separated by column chromatography (the stationary phase was 200-300 mesh silica gel, and the mobile phase was a mixture of ethyl acetate and n-hexane, and the volume ratio of ethyl acetate to n-hexane was increased from 1:10 to 1:5). The solid obtained after drying was the organic second-order nonlinear optical chromophore BHG2 with a D-π-A structure, and the yield was 34.1%.

[0038] HRMS (ESI) (M+H)+ for BHG1: calcd for (C 96 H 98 N4O6Si2+H)+: 1459.7098; found: 1459.7062. 1H NMR for BHG1 (400 MHz, CDCl3) δ 8.05 – 7.95 (m, 1H), 7.73(d, J = 7.5 Hz, 4H), 7.34 (dt, J = 11.7, 8.0 Hz, 10H), 7.26 – 7.19 (m, 5H),7.04 (dd, J = 17.5, 8.6 Hz, 8H), 6.80 – 6.63 (m, 12H), 6.37 (d, J = 14.9 Hz,1H), 4.09 (t, J = 5.6 Hz, 4H), 3.83 (t, J = 5.3 Hz, 4H), 3.69 (s, 3H), 2.45(d, J = 18.4 Hz, 4H), 1.68 (s, 6H), 1.06 (s, 6H), 0.94 (s, 18H), 0.15 (s,12H). The obtained organic second-order nonlinear optical chromophore molecule with D-π-A structure has a thermal decomposition temperature of 291°C and a glass transition temperature of 145°C; it has good solubility in polar solvents such as acetone, chloroform or ethanol and non-polar solvents such as ether.

[0039] Example 2 The organic second-order nonlinear optical chromophore with a D-π-A structure as shown below was synthesized: The synthetic route is as follows: The synthesis of compound 1 represented by formula 1, compound 2 represented by formula 2, compound 3 represented by formula 3, and compound 4 represented by formula 4 is the same as that of Example 1.

[0040] 1) Synthesis of organic second-order nonlinear optical chromophore with D-π-A structure (shown as BHG2 in the formula) 1.2 mmol of compound 4 obtained in step 4 and 0.45 g (1.4 mmol) of trifluoro-substituted tricyanodihydrofuran (CF3-TCF) were dissolved in 20 mL of ultra-dry ethanol and then refluxed at 80 °C for 0.5 h. After the reaction was completed, the solvent was removed by rotary evaporation, and the crude product was separated by column chromatography (the stationary phase was 200-300 mesh silica gel, and the mobile phase was a mixture of ethyl acetate and n-hexane, and the volume ratio of ethyl acetate to n-hexane was increased from 1:10 to 1:5). The solid obtained after drying was the organic second-order nonlinear optical chromophore BHG2 with a D-π-A structure, and the yield was 38.2%.

[0041] MS(MALDI-TOF), m / z:1575.6972 (M+); 1 H NMR (400 MHz, CDCl3) δ 8.00 (t, J =13.3 Hz, 1H), 7.73 (d, J = 7.5 Hz, 4H), 7.54 – 7.48 (m, 5H), 7.40 – 7.29 (m,10H), 7.23 (dd, J = 13.3, 5.7 Hz, 6H), 7.04 (dd, J = 18.4, 8.5 Hz, 8H), 6.81 (d, J = 16.1 Hz, 1H), 6.72 – 6.63 (m, 10H), 6.44 (d, J = 14.7 Hz, 1H), 4.09 (t, J = 5.4Hz, 4H), 3.84 (d, J = 5.1 Hz, 4H), 3.65 (s, 3H), 2.42 (s, 2H), 2.30 (s, 2H), 1.01 (s, 3H), 0.94 (s, 21H), 0.14 (s, 12H). The obtained organic second-order nonlinear optical chromophore molecule with D-π-A structure has a thermal decomposition temperature of 241°C and a glass transition temperature of 131°C; it has good solubility in polar solvents such as acetone, chloroform or ethanol and non-polar solvents such as ether.

[0042] Example 3 The organic second-order nonlinear optical chromophore with a D-π-A structure as shown below was synthesized: The synthesis route is as follows: The synthesis of compound 1 represented by formula 1, compound 2 represented by formula 2, and compound 3 represented by formula 3 is the same as that of Example 1.

[0043] 1) Synthesis of compound 4 shown in the formula 6.79 g (26 mmol) of pentafluorobenzyl bromide, 13.65 g (13 mmol) of compound 3, 3.63 g (26 mmol) of potassium carbonate and 0.33 g (2 mmol) of potassium iodide were dissolved in ultra-dry DMF, and the mixture was heated at 85 °C for 20 hours; after cooling to room temperature, the mixture was poured into water; the mixture was extracted with dichloromethane, dried over magnesium sulfate, and the solvent was removed by rotary evaporation; the residue was separated by column chromatography (with 200-300 mesh silica gel as the stationary phase and a mixture of n-hexane and ethyl acetate as the mobile phase, wherein the volume ratio of n-hexane to ethyl acetate was 1:14), and an orange-yellow solid was obtained after drying, which was compound 4 with a yield of 80%.

[0044] MS(MALDI-TOF), m / z:1409.4725 (M+); 1 H NMR (400 MHz, CDCl3) δ 10.09 (d,J = 8.2 Hz, 1H), 7.73 (d, J = 7.4 Hz, 4H), 7.33 (t, J = 7.8 Hz, 10H), 7.24(d, J = 4.3 Hz, 5H), 7.09 (dd, J = 18.1, 7.9 Hz, 8H), 6.79 (d, J = 7.9 Hz,4H), 6.75 – 6.64 (m, 7H), 6.31 (d, J = 8.2 Hz, 1H), 5.02 (s, 4H), 4.09 (t, J= 5.2 Hz, 4H), 3.82 (s, 4H), 3.63 (s, 3H), 2.73 (s, 2H), 2.38 (s, 2H), 1.04 (d, J = 12.7 Hz, 6H). 2) Synthesis of an organic second-order nonlinear optical chromophore with a D-π-A structure (compound BHG3 shown in the formula) 1.2 mmol of compound 4 and 0.28 g (1.4 mmol) of tricyanodihydrofuran (TCF) were dissolved in 20 mL of ultra-dry ethanol and then refluxed at 80 °C for 0.5 h. After the reaction was completed, the solvent was removed by rotary evaporation and the crude product was separated by column chromatography (the stationary phase was 200-300 mesh silica gel, and the mobile phase was a mixture of ethyl acetate and n-hexane, and the volume ratio of ethyl acetate to n-hexane was increased from 1:10 to 1:5). The solid obtained after drying was the organic second-order nonlinear optical chromophore BHG3 with a D-π-A structure, and the yield was 41.2%.

[0045] HRMS (ESI) (M+H)+ for BHG3: calcd for (C 96H 72 F 10 N4O6+H)+: 1591.5365; found: 1591.5342. 1 H NMR for BHG3 (400 MHz, CDCl3) δ 7.99 (t, J = 13.2 Hz,1H), 7.74 (d, J = 7.5 Hz, 4H), 7.56 – 7.48 (m, 5H), 7.41 – 7.29 (m, 10H),7.09 (dd, J = 16.1, 8.3 Hz, 8H), 6.83 – 6.66 (m, 12H), 6.45 (d, J = 14.6 Hz,1H), 5.03 (s, 4H), 4.11 (s, 4H), 3.85 (s, 4H), 3.65 (s, 3H), 2.43 – 2.22 (m,4H), 0.98 (d, J = 23.9 Hz, 12H). The obtained organic second-order nonlinear optical chromophore molecule with D-π-A structure has good thermal stability, a thermal decomposition temperature of 305°C, and a glass transition temperature of 143°C; it has good solubility in polar solvents such as acetone, chloroform or ethanol and non-polar solvents such as ether and hexadecane.

[0046] Example 4 The organic second-order nonlinear optical chromophore with a D-π-A structure as shown below was synthesized: The synthesis route is as follows: The synthesis of compound 1 represented by formula 1, compound 2 represented by formula 2, compound 3 represented by formula 3, and compound 4 represented by formula 4 is the same as that of Example 3.

[0047] 1) Synthesis of an organic second-order nonlinear optical chromophore with a D-π-A structure (compound BHG4 shown in the formula) 1.2 mmol of compound 4 and 0.45 g (1.4 mmol) of trifluoro-substituted tricyanodihydrofuran (CF3-TCF) were dissolved in 20 mL of ultra-dry ethanol and then refluxed at 80 °C for 0.5 h. After the reaction was completed, the solvent was removed by rotary evaporation and the crude product was separated by column chromatography (the stationary phase was 200-300 mesh silica gel, and the mobile phase was a mixture of ethyl acetate and n-hexane, and the volume ratio of ethyl acetate to n-hexane was increased from 1:10 to 1:5). The solid obtained after drying was the organic second-order nonlinear optical chromophore BHG4 with a D-π-A structure, with a yield of 48.2%.

[0048] MS(MALDI-TOF),m / z: 1707.5239(M+); 1 H NMR (400 MHz, CDCl3) δ 7.99 (t, J =13.2 Hz, 1H), 7.74 (d, J = 7.5 Hz, 4H), 7.56 – 7.48 (m, 5H), 7.41 – 7.29 (m,10H), 7.24 (d, J = 5.5 Hz, 5H), 7.09 (dd, J = 16.1, 8.3 Hz, 8H), 6.83 – 6.66 (m,12H), 6.45 (d, J = 14.6 Hz, 1H), 5.03 (s, 4H), 4.11 (s, 4H), 3.85 (s, 4H), 3.65(s, 3H), 2.43 – 2.22 (m, 4H), 0.98 (d, J = 23.9 Hz, 6H); The obtained organic second-order nonlinear optical chromophore molecule with D-π-A structure has good thermal stability, a thermal decomposition temperature of 255°C, and a glass transition temperature of 130°C; it has good solubility in polar solvents such as acetone, chloroform or ethanol and non-polar solvents such as ether and hexadecane.

[0049] Example 5 1) 0.06 g of amorphous polycarbonate (APC) was added to 1.00 mL of chloroform, and stirred for 3-5 hours until APC was completely dissolved, and then 0.02 g of the organic second-order nonlinear optical chromophore compound synthesized in Examples 1, 2, 3, and 4 (wherein BHG1, BHG2, BHG3, and BHG4) was added to obtain a mixed solution of the organic second-order nonlinear optical chromophore compound and APC, and the obtained mixed solution was filtered and coated on an ITO glass substrate by spin coating (controlling the rotation speed at 800-1200 rpm), and then dried in a vacuum drying oven at 50°C for 24 hours. The thickness of the obtained polymer film was about 1.3-1.9 μm.

[0050] 2) 10 mg of the organic second-order nonlinear optical chromophore compound synthesized in Examples 2 and 4 (BHG2 and BHG4 in the formula) was added to 190 mg of 1,1,2-trichloroethane and stirred for 3 to 5 hours until the chromophore was completely dissolved to obtain a solution of a pure organic second-order nonlinear optical chromophore compound, which was then coated on an ITO glass substrate by spin coating. The rotation speed was controlled to be 600 to 800 rpm, and then dried in a vacuum drying oven at 50°C for 24 hours. The thickness of the resulting polymer film was about 0.6 to 1.0 μm.

[0051] Example 6 Example 5: Determination of polarization and electro-optic coefficient of the electro-optical film prepared 1) The polymer film obtained by contact polarization of the organic second-order nonlinear optical chromophore compounds of Examples 1, 2, 3, and 4 (wherein BHG1, BHG2, BHG3, BHG4, and JRD1) and APC is subjected to contact polarization. The conditions for contact polarization of the polarized organic film are: the polarization temperature is about 120-150°C, the polarization time is 5-15 minutes, the polarization voltage is controlled at about 50-150 V / μm, and the electro-optic coefficient (r 33 ).

[0052] Electro-optic coefficient (r 33 ) By simple reflection method (see CC Teng, HT Man, Simple reflection technique for measuring the electrooptic coefficient of poled polymers, Appl. Phys. Lett., 1990, 56, 1734.), it was found that the BH1 / APC electro-optical film had a maximum electro-optical coefficient of 145 pm / V, the BH2 / APC electro-optical film had a maximum electro-optical coefficient of 218 pm / V, the BH3 / APC electro-optical film had a maximum electro-optical coefficient of 83 pm / V, and the BHG4 / APC electro-optical film had a maximum electro-optical coefficient of 152 pm / V.

[0053] 2) The thin film material formed by the organic second-order nonlinear optical chromophore compounds of Examples 2 and 4 (BHG2 and BHG4 in the formula) was subjected to contact polarization at a polarization temperature of 130-140°C, a polarization time of 5-10 minutes, and a polarization voltage of about 50-150 V / μm. The electro-optic coefficient (r 33 ).

[0054] Electro-optic coefficient (r 33) The maximum electro-optic coefficient of the BHG2 pure electro-optic film was measured to be 304 pm / V, and the maximum electro-optic coefficient of the BHG4 pure electro-optic film was measured to be 221 pm / V by a simple reflection method (see CC Teng, HT Man, Simple reflection technique for measuring the electrooptic coefficient of poled polymers, Appl. Phys. Lett., 1990, 56, 1734.).

[0055] Example 7 Example 6 Electro-optical performance stability test of pure BHG2 chromophore film after polarization: The polarized BHG2 electro-optical film was heated to 60°C and the electro-optic coefficient was tested every 24 to 100 hours for 500 hours. The stability curve of its electro-optical performance is shown in the figure below. Figure 1 The electro-optical properties of the polarized BHG2 film have good thermal stability. After being heated to 60°C, the electro-optical properties decay slightly within the first 24 hours, and then the electro-optic coefficient remains basically unchanged. After being placed at 60°C for 500 hours, the electro-optical properties of the material can still maintain about 86% of the initial value. Therefore, the prepared polarized electro-optical film material can be used as a key core material for the development of electro-optical modulators.

[0056] Example 6 Electro-optical performance stability test of pure JRD1 (WW Jin, PV Johnston, DL Elder, AF Tillack, et al. Appl. Phys. Lett. 2014, 104, 243304.) chromophore film after polarization: JRD1 is a self-forming film material with a relatively high electro-optic coefficient. Many electro-optic devices have JRD1 as an active material. The electro-optic performance stability of the BHG series self-forming film materials studied in the present invention is compared with that of JRD1 to determine its technical innovation.

[0057] The polarized JRD1 electro-optical film was heated to 60°C and the electro-optic coefficient was tested every 24 to 100 hours for 500 hours. The stability curve of its electro-optical performance is shown in the figure. Figure 1As shown. When the JRD1 film after polarization is heated at 60°C, the electro-optical performance decays to 52.4% of the original value within the first 24 hours, and decays to 48.8% after 48 hours. Thereafter, the electro-optic coefficient remains basically unchanged. After being placed at 60°C for 500 hours, the electro-optical performance of the material can still be maintained at about 47% of the initial value. It can be seen that the organic second-order nonlinear optical chromophore BHG2 protected by this patent has better thermal stability than the reported chromophore JRD1. This is because the introduction of the substituted bisphenol fluorene steric hindrance group can, on the one hand, weaken the dipole interaction and improve the polarization efficiency, and on the other hand, the rigid steric hindrance can effectively increase the glass transition temperature of the chromophore, thereby improving the thermal stability of the material.

[0058] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A compound, characterized in that It has the following structural formula: ； in: R1 represents H, substituted or unsubstituted C1~C 20 Alkyl, substituted or unsubstituted benzyl, phenyl acyl, C1~C 20 Aliphatic acyl or C1~C 10 A silyl group, or a group consisting of any of the above groups; R2 represents H, substituted or unsubstituted C1~C 20 Alkyl, substituted or unsubstituted C1~C 20 Alkoxy, substituted or unsubstituted C1~C 20 alkylthio or silyloxy, or a group consisting of any of the above groups; R3 and R4 are each independently, identical or different and represent substituted or unsubstituted C1~C 20 Alkyl, substituted or unsubstituted C6~C 30 phenyl, or a group consisting of any of the above groups; When substituted, the substituent includes hydroxyl, halogen or aromatic heterocycle, the heteroatom includes one or more of nitrogen atom, sulfur atom and oxygen atom; the halogen includes fluorine and / or chlorine.

2. The compound according to claim 1, characterized in that R1 represents H, substituted or unsubstituted C1~C5 alkyl, substituted or unsubstituted benzyl, phenyl acyl, C1~C 20 aliphatic acyl, silane, or a group consisting of any of the above groups; when substituted, the substituent includes hydroxyl or fluorine; R2 represents a substituted or unsubstituted C1~C5 alkyl group, a substituted or unsubstituted C1~C5 alkoxy group, a substituted or unsubstituted C1~C5 alkylthio group or a silyl group; when substituted, the substituent includes a hydroxyl group or a fluorine group; R3 and R4 are each independently, the same or different, substituted or unsubstituted C1~C5 alkyl, substituted or unsubstituted C6~C 18 Phenyl; When substituted, the substituents include hydroxy or halogen; the halogen includes fluorine and / or chlorine; Preferably, R1 represents a silyl group or a substituted or unsubstituted benzyl group; the silyl group includes a trimethylsilyl group, a tert-butyldimethylsilyl group or a dimethylphenylsilyl group; R2 represents a substituted or unsubstituted C1~C3 alkoxy group; R3 represents methyl or trifluoromethyl; R4 represents a substituted or unsubstituted C1~C3 alkyl, a substituted or unsubstituted C6~C 12 Phenyl; When substituted, substituents include hydroxy or fluorine.

3. The method for preparing the compound according to claim 1 or 2, characterized in that: Its synthetic route is as follows: ; wherein the groups represented by R1, R2, R3, R4 in the compounds involved in each step and the obtained compound products are the same as those indicated in claims 1 to 3.

4. The method for preparing the compound according to claim 3, characterized in that: Including the following method : S1: The mixture was dissolved in redistilled tetrahydrofuran with p-toluenesulfonyl chloride, and triethylamine was added dropwise under nitrogen and ice bath conditions for 1 to 1.5 hours. The ice bath equipment was removed and the sealed system was allowed to react overnight at room temperature. After the reaction, the reaction solution was poured into deionized water, extracted with ethyl acetate, the organic phases were combined, and the combined organic phases were dried. The ethyl acetate was removed by rotary evaporation, and column chromatography was performed to obtain the obtained product. ; S2: The mixture is dissolved in redistilled N,N-dimethylformamide with 9-fluorene bisphenol and anhydrous potassium carbonate, and heated to 90-110 °C under nitrogen protection for 20-24 hours. After the reaction is completed, it is poured into deionized water to obtain an orange solution, which is extracted with ethyl acetate. The organic phases are combined and washed with a saturated sodium chloride solution. The organic phase is dried and then the organic solvent is removed by rotary evaporation. The organic phase is separated by column chromatography and dried to obtain ; Wherein, R2 in the compound involved in each step is the same as that indicated in claims 1 to 3; Preferably, in S1, The molar ratio with p-toluenesulfonyl chloride is 1:(2~4); and / or S2, , the molar ratio of 9-fluorene bisphenol and anhydrous potassium carbonate is 1:(4~6):(12~14).

5. The method for preparing the compound according to claim 4, characterized in that: Also includes: S3: and imidazole are dissolved in redistilled N,N-dimethylformamide, and the compound containing R1 is slowly added to the mixed solution under N2 protection, and the reaction is carried out at 20-30 °C; after the reaction is completed, it is poured into deionized water and extracted with n-hexane, the organic phase is washed with brine, the solvent is removed by rotary evaporation after drying, the residue is separated by column chromatography, and the obtained product is obtained after drying. ; S4: The tricyandihydrofuran electron acceptor was dissolved in anhydrous ethanol and refluxed at 80-100°C for 0.5-1 hour. After the reaction was completed, the mixture was cooled to 20-30°C, and the ethanol and water were removed by rotary evaporation. The mixture was separated by column chromatography and then dried to obtain ; Wherein, the groups represented by R2, R3, and R4 in the compounds involved in each step are the same as those indicated in claims 1 to 3, and R1 represents H, substituted or unsubstituted C1 to C 20 Alkyl, phenyl acyl, C1~C 20 Aliphatic acyl or C1~C 10 A silyl group, or a group consisting of any of the above groups; Preferably, The molar ratio with imidazole is 1:(2~3); and / or The molar ratio with chlorosilane is 1:(2~3); and / or The molar ratio of tricyandihydrofuran electron acceptor is 1:(1~1.5); or, S3': The substituted or unsubstituted benzyl compound, potassium carbonate and potassium iodide are dissolved in anhydrous N,N-dimethylformamide, heated at 80-90 °C for 20-24 hours, and after the reaction is completed and cooled to room temperature, the product is poured into water, extracted with dichloromethane, and the organic phase is dried, the solvent is removed by rotary evaporation, and column chromatography is performed to obtain S4': The tricyandihydrofuran electron acceptor was dissolved in anhydrous ethanol, sealed and refluxed at 70-90 °C for 0.5-1 hour, and the solvent was removed by rotary evaporation after the reaction was completed. The product was separated by column chromatography and dried to obtain ; Wherein, R1' is a substituted or unsubstituted benzyl group; Preferably, With a substituted or unsubstituted benzyl compound, potassium carbonate, and potassium iodide in a molar ratio of 1:2:2:(6-7); and / or, The molar ratio of tricyandihydrofuran electron acceptor is 1:(1~2).

6. Use of the compound according to claim 1 or 2 or the compound prepared by the preparation method according to any one of claims 3 to 5 in an organic nonlinear optical chromophore.

7. An organic nonlinear optical chromophore, characterized in that: It contains the compound according to claim 1 or 2 or the compound prepared by the preparation method according to any one of claims 4 to 5.

8. Use of the compound according to claim 1 or 2 or the compound prepared by the preparation method according to any one of claims 3 to 5 in polarized polymer films.

9. A polarized polymer film, characterized in that It is mainly prepared from the compound described in claim 1 or 2 or the compound prepared by the preparation method described in any one of claims 4 to 5; Preferably, the polarized polymer film is mainly made of the compound and amorphous polycarbonate in a mass ratio of 1:1-100.

10. A material for an electro-optic modulator, characterized in that: It contains the polarized polymer film according to claim 9.

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