Heteroatom helicene compound as well as preparation method and application thereof

Abstract

The invention discloses a heteroatom helicene compound as well as a preparation method and application thereof. The heteroatom helicene compound is novel in structure, and the emission wave band is in a blue light region and a green light region of 400-600nm; the preparation method is simple; the compound has high fluorescence quantum yield and light-emitting asymmetric factors, and is expected to be used for preparing efficient light-emitting devices.

Description

(I) TECHNICAL FIELD

[0001] The application belongs to the technical field of organic chemistry, and specifically relates to a heteroatom spiro-olene compound and a preparation method and application thereof. (II) BACKGROUND

[0002] Spiro-olene is a kind of polycyclic aromatic hydrocarbon compound (PAHs) with unique helical chirality composed of adjacent fused aromatic rings. The helical chirality endows it with significant chiral optical properties, and it has been regarded as one of the most promising circularly polarized luminescence (CPL) dyes (Y. Shen and C.-F. Chen, Chem. Rev., 2012, 112, 1463). Although conventional all-carbon spiro-olene can produce CPL, its fluorescence intensity is usually weak and the emission band is limited to the blue light region. In addition, the circularly polarized luminescence and circular dichroism (CD) are more sensitive to substituents than the spiro-olene configuration itself (Y. Nakai, T. Mori and Y. Inoue, J. Phys. Chem. A, 2013, 117, 83).

[0003] Embedding heteroatoms in the spiro-olene skeleton can regulate the electronic state. Such heteroatom spiro-olene compounds exhibit strong fluorescence and CPL activity in the visible light to near-infrared (NIR) region. However, the existing synthesis of heteroatom-containing spiro-olene has the following difficulties:

[0004] 1) High ring strain: The helical structure of spiro-olene leads to a highly twisted molecule, especially for multiple spiro-olene (such as five-fold [9] spiro-olene), the ring strain is extremely large, and side reactions such as ring opening and isomerization are prone to occur during synthesis (Angew. Chem. Int. Ed. 2022, 61, e202204334);

[0005] 2) Introduction of heteroatoms increases instability: The doping of heteroatoms such as sulfur (S) and nitrogen (N) can change the electronic distribution and increase the intramolecular tension, resulting in the difficulty of stable existence of intermediates. (III) SUMMARY

[0006] The purpose of the present application is to provide a heteroatom spiro-olene compound and a preparation method and application thereof. The heteroatom spiro-olene compound has a novel structure and emits in the blue light region and green light region of 400-600 nm. The preparation method is simple: first, one or both hydroxyl groups of the heteroatom binaphthol are protected by N-phenyl bis(trifluoromethanesulfonyl) imine, and then they are converted into a heteroatom spiro-olene with strong fluorescence and CPL performance by coupling method. The present application overcomes the defects of existing spiro-olene, such as weak fluorescence, emission band limited to blue light region, and complex preparation method.

[0007] The technical scheme adopted by the present application is as follows:

[0008] In a first aspect, the present application provides a heteroatom-spirofullerene compound, which has a structure as shown in Formula I:

[0009]

[0010] In Formula I, R 1 is hydrogen, methyl, methoxy, bromine, chlorine, iodine, phenyl, benzyl, trifluoromethyl, ester group; R 2 is hydrogen, methyl, methoxy, bromine, chlorine, iodine, phenyl, benzyl, trifluoromethyl, ester group; and X is O or NH.

[0011] Further, the compound I is one of the following:

[0012]

[0013] In a second aspect, the present application provides a preparation method of the heteroatom-spirofullerene compound, which comprises the following steps:

[0014] (1) Compound II is dissolved in tetrahydrofuran at 0°C, sodium tert-butoxide (tBuONa) is added, constant temperature stirring is performed for 5-10 minutes (preferably 5 minutes), then N-phenyl bis(trifluoromethanesulfonyl) imide (PhNTf2) is added, stirring is performed at room temperature, and TLC is used to monitor the reaction; after the reaction is completed, water is added to the reaction solution, extraction is performed with ethyl acetate, the organic phases are combined, anhydrous sodium sulfate is used for drying, and then the solution is concentrated under reduced pressure to 1-10% (preferably 5%) of the original volume; the concentrated solution is subjected to silica gel column chromatography with petroleum ether and ethyl acetate as eluents in a volume ratio of 15:1-20:1, pressure elution is performed for 5-15 (preferably 10) column volumes, the effluent with an R f value of 0.2-0.4 is collected, and rotary evaporation is performed under reduced pressure until dryness, so as to obtain the compound III;

[0015] (2) All the compound III obtained in the above step (1) and K3PO4 are dissolved in N,N-dimethylformamide, tetrakis(triphenylphosphine)palladium is added under the protection of argon, and heating is performed at 100-150°C for 20-30 hours (preferably 120°C for 24 hours); after the reaction is completed, water is added for quenching, extraction is performed with ethyl acetate, anhydrous sodium sulfate is used for drying, and then the solution is concentrated under reduced pressure to 1-10% (preferably 5%) of the original volume; the concentrated solution is subjected to silica gel column chromatography with petroleum ether as an eluent (or with petroleum ether and ethyl acetate as eluents in a volume ratio of 15:1-20:1), pressure elution is performed for 5-15 (preferably 10) column volumes, the effluent with an R f value of 0.2-0.4 is collected, and rotary evaporation is performed under reduced pressure until dryness, so as to obtain the compound I;

[0016] The reaction formula is as follows:

[0017]

[0018] In Formula II, R1 is hydrogen, methyl, methoxy, bromine, chlorine, iodine, phenyl, benzyl, trifluoromethyl, ester group; R 2 is hydrogen, methyl, methoxy, bromine, chlorine, iodine, phenyl, benzyl, trifluoromethyl, ester group; X is O or NH; R 1 , R 2 , X are the same as formula II.

[0019] Further, in step (1), the mass ratio of compound II to sodium tert-butoxide is 1:1-5 (preferably 1:1.5); the mass ratio of compound II to N-phenyl bis(trifluoromethanesulfonyl) imide is 1:1-5 (preferably 1:1.5); the volume of tetrahydrofuran is 5-15 mL / mmol (preferably 10 mL / mmol) based on the mass of compound II.

[0020] Further, in step (2), the mass ratio of potassium phosphate to compound II is 1-5:1 (preferably 2:1); the mass ratio of tetrakis(triphenylphosphine)palladium to compound II is 0.1-1:1 (preferably 0.2:1); the volume of N,N-dimethylformamide is 5-15 mL / mmol (preferably 10 mL / mmol) based on the mass of compound II.

[0021] In a third aspect, the present application also provides a use of the heteroatom spirofullerene compound in the preparation of a circularly polarized luminescence (CPL) material.

[0022] Further, the heteroatom spirofullerene compound is expected to be used in tumor detection, organic electroluminescence diode (OLED), fluorescent pavement and identification, or DNA / RNA staining.

[0023] In a fourth aspect, the present application provides a circularly polarized luminescence material prepared from the heteroatom spirofullerene compound.

[0024] Compared with the prior art, the present application has the following beneficial effects:

[0025] Through reasonable design, the present application provides a series of novel heteroatom spirofullerene compounds with long emission time and stability compared with heterocyclic 【5】 spirofullerene (Chem. Commun., 2025, 61, 4757-4773).

[0026] After synthesizing the heteroatom binaphthol prepared in the previous development, the hydroxyl group is protected by N-phenyl bis(trifluoromethanesulfonyl) imide, and then converted into the required spirofullerene compound under coupling conditions, a simple and efficient synthesis strategy is developed, which provides a synthesis basis for the subsequent development and application of luminescent spirofullerene.

[0027] The prepared heteroatom spiro-olefin compound is used for preparing circularly polarized luminescent material, and the circularly polarized luminescent material has high fluorescence quantum yield and luminescence asymmetry factor, and is expected to be used for preparing high-efficiency luminescent devices. (VI)DETAILED DESCRIPTION

[0028] Figure 1 The H NMR spectrum of compound I-1 is shown in the following figure. 1 The H NMR spectrum of compound I-1 is shown in the following figure.

[0029] Figure 2 The H NMR spectrum of compound I-1 is shown in the following figure. 13 The H NMR spectrum of compound I-1 is shown in the following figure.

[0030] Figure 3 The H NMR spectrum of compound I-1 is shown in the following figure. 1 The H NMR spectrum of compound I-1 is shown in the following figure.

[0031] Figure 4 The H NMR spectrum of compound I-1 is shown in the following figure. 13 The H NMR spectrum of compound I-1 is shown in the following figure.

[0032] Figure 5 The H NMR spectrum of compound I-1 is shown in the following figure.

[0033] Figure 6 The H NMR spectrum of compound I-1 is shown in the following figure.

[0034] Figure 7 The H NMR spectrum of compound I-1 is shown in the following figure.

[0035] Figure 8 The H NMR spectrum of compound I-1 is shown in the following figure.

[0036] Figure 9 The H NMR spectrum of compound I-1 is shown in the following figure. lum The H NMR spectrum of compound I-1 is shown in the following figure. (VI)DETAILED DESCRIPTION

[0037] The application will be further described in combination with specific examples, but the protection scope of the application is not limited to the following:

[0038] The room temperature in the examples of the application refers to 25-30℃.

[0039] Example 1, preparation of naphtho[1',2':4,5]furo[2,3-h]quinoline I-1:

[0040]

[0041] (1) At 0℃, 8-(2-hydroxynaphth-1-yl)-7-hydroxyquinoline II-1 (0.2 mmol) was dissolved in tetrahydrofuran (2 mL), and sodium tert-butoxide (0.3 mmol, 1.5 equiv.) was added. The mixture was stirred at constant temperature for 5 minutes, followed by the addition of N-phenylbis(trifluoromethanesulfonyl)imide (0.3 mmol, 1.5 equiv.). The mixture was stirred at room temperature, and the reaction was monitored by TLC. The developing solvent was ethyl acetate and petroleum ether in a volume ratio of 1:20. After the reaction was completed, water (10 mL) was added to the reaction solution, and the mixture was extracted with ethyl acetate (3 × 10 mL). The organic phases were combined, dried over anhydrous sodium sulfate, and concentrated under reduced pressure to 5% of the original volume. The concentrate was eluted with petroleum ether and ethyl acetate in a volume ratio of 20:1 and subjected to silica gel column chromatography (silica gel particle size 100-200 mesh, column packing volume of two-thirds of the column volume). Ten column volumes were eluted under pressure, and R was collected. f The eluent with a value of 0.4 was evaporated to dryness under reduced pressure to obtain 0.1 g of concentrate, which is 8-(2-hydroxynaphth-1-yl)-7-quinolinyl trifluoromethanesulfonate III-1;

[0042] (2) Dissolve all the concentrates III-1 and K3PO4 (0.4 mmol, 2.0 equiv.) from step (1) in N,N-dimethylformamide (2 mL), add tetrakis(triphenylphosphine)palladium (0.04 mmol) under argon protection, and heat at 120 °C for 24 hours. After the reaction is complete, quench with water (10 mL), extract with ethyl acetate (3 × 10 mL), dry with anhydrous sodium sulfate, and concentrate under reduced pressure to 5% of the original volume. Elute the concentrate with petroleum ether using silica gel column chromatography (silica gel particle size 100-200 mesh, column packing volume of two-thirds of the column volume), elute under pressure for 10 column volumes, and collect R. f The eluent with a pH of 0.4 was rotary evaporated under reduced pressure to dryness, yielding 29.6 mg of a pale yellow solid product (55% yield), which is compound I-1. The 1H NMR spectrum is shown below. Figure 1 As shown, 13 The C NMR spectrum is shown below. Figure 2 As shown.

[0043] Example 2, Compounds I-2 to I-6

[0044] Following a method similar to Example 1, only R in Compound II is removed. 1 R 2 Replace X as shown in Table 1, and collect R. f The eluent with a value of 0.2-0.4 yielded the corresponding compound I, of which I-5... 1 H NMR spectrum as follows Figure 3 As shown, 13 C NMR spectrum as follows Figure 4The results of the nuclear magnetic hydrogen spectrum and high resolution mass spectrum data of the above compounds are listed in Table 1. It can be seen from the above that the structures of the above compounds are correct, and they are all compounds shown in Formula I.

[0045] Table 1 Nuclear magnetic resonance hydrogen spectrum data and high resolution mass spectrum data of compounds shown in Formula I

[0046]

[0047]

[0048] Example 3, Test of light emission and absorption performance of compound I:

[0049] 1. Light absorption performance

[0050] (1) Sample solution: 1 mg of compound I-1 to I-6 prepared by the method of Example 1 was dissolved in 2 mL of dichloromethane (DCM) solvent to obtain a sample solution, which was placed in a 10 mm quartz cuvette for testing.

[0051] (2) UV-Vis spectrum testing method:

[0052] The UV-Vis absorption spectrum of each sample was collected by using a Hitachi U-3900 spectrometer. The results are shown in Figure 5 It can be seen from the above that the absorption spectrum of compound I-1 to I-6 in dichloromethane shows similar characteristics in the wavelength range of 331-365 nm.

[0053] 2. Light emission performance:

[0054] (1) Sample solution: 1 mg of compound I-1 to I-6 prepared by the method of Example 1 was dissolved in 2 mL of dichloromethane solvent to obtain a sample solution, which was then added to a 10 mm quartz cuvette for testing.

[0055] (2) Testing method:

[0056] Fluorescence spectrum: The fluorescence spectrum was collected by using a Hitachi F-4500 fluorescence spectrophotometer. Test parameters: voltage: 400 V; excitation / emission slit width: 2.5 nm; scanning speed: 1200 nm / min.

[0057] Fluorescence quantum yield: Determined by HORIBA FluoroMax+ system with an integrating sphere.

[0058] Fluorescence decay curve: Recorded using Edinburgh Instruments FLS 980 spectrometer; excitation wavelength: 371 nm.

[0059] Lifetime value: Obtained by single / multi-exponential fitting of the decay curve.

[0060] (3) Results

[0061] see compound lifetime values. Figure 6 As shown, compounds I-1 to I-4 are all oxaspirenes, and compounds I-5 to I-6 are all azespirenes. Among them, compound I-2 has a methoxy group introduced at the 2 position, resulting in the longest decay time. Compounds I-3 and I-6 both have a methyl group introduced, but the former is an oxaspirene and the latter is an azespirene. The former has a slightly longer decay time than the latter.

[0062] Normalized fluorescence spectra of the compound are shown in the figure. Figure 7 As shown, electron-donating groups induce red shift: the introduction of methoxy (OMe) at the 2 position of [5] azirhelicene I-2 causes a red shift in fluorescence emission to 426 nm (I-1: 408 nm), which is due to enhanced π electron delocalization or increased density of states; weak electron-donating groups have no significant effect: the introduction of methyl (Me) at the nitrogen ortho (2 position) has almost no effect on the fluorescence peak position (I-3: 409 nm); electron-withdrawing groups induce a slight red shift: chlorination (Cl) causes the emission peak of I-4 to shift to 414 nm; fused ring extension effect: compared with I-1, I-5 containing the stronger electron-donating group carbazole red shifts to 415 nm, which is attributed to the extension of conjugation length, enhanced electron-donating ability and homogenization of π electron delocalization; anomalous blue shift phenomenon: unlike the I-1 to I-4 series, I-6 with chlorination at the 2 position shows a blue shift (409 nm).

[0063] The fluorescence quantum yields of compounds I-1, I-2, I-3, I-5, and I-6 were measured to be 47.0%, 46.5%, 35.2%, 66.9%, and 32.1%, respectively.

[0064] 3. Circularly Polarized Luminescence Experiment

[0065] Preparation of circularly polarized luminescent material: 1 mmol of helicene compound I-5 was dissolved in 1 mL of DCM, followed by the addition of 1 mmol of L-camphor sulfonic acid. After standing at room temperature for 10 minutes, the yellow solid was collected, which is the CPL film, with the structure shown below. Figure 9 As shown in Figure A.

[0066] The fluorescence detection image of the CPL film is shown below. Figure 8 As shown, the fluorescence quantum yield is 31%. The emission asymmetry factor (g) of the CPL thin film was measured at 375 nm using a circularly polarized luminescence analyzer (JASCOCPL-300). lum CPL spectrum, results are shown in [link to CPL spectrum]. Figure 9 As shown in Figures B and D; fluorescence intensity was detected using a Hitachi F-4500 fluorescence spectrophotometer, and the results are shown in Figure 1. Figure 9 As shown in C.

[0067] The emission wavelength of the CPL film was detected at 530 nm, similar to the CPL wavelength (offset is normal), and the asymmetry factor was finally calculated to be 0.01, g lum = 0.01 (540 nm).

Claims

1. A heteroatom-containing helicene compound, characterized in that, The structure of the compound is shown in Formula I: In Equation I, R 1 The radicals are hydrogen, methyl, methoxy, bromine, chlorine, iodine, phenyl, benzyl, trifluoromethyl, and ester; R 2 The radicals are hydrogen, methyl, methoxy, bromine, chlorine, iodine, phenyl, benzyl, trifluoromethyl, or ester; X is O or NH.

2. The heteroatom-containing helicene compound according to claim 1, characterized in that, The compound is one of the following:

3. A method for preparing the heteroatom helicene compound of claim 1, characterized in that, The method is as follows: (1) At 0℃, compound II was dissolved in tetrahydrofuran, sodium tert-butoxide was added, and the mixture was stirred at a constant temperature for 5-10 minutes. Then, N-phenylbis(trifluoromethanesulfonyl)imide was added, and the mixture was stirred at room temperature. The reaction was monitored by TLC. After the reaction was completed, water was added to the reaction solution, and the solution was extracted with ethyl acetate. The organic phases were combined, dried over anhydrous sodium sulfate, and concentrated under reduced pressure to 1-10% of the original volume. The concentrate was subjected to silica gel column chromatography with petroleum ether and ethyl acetate in a volume ratio of 15:1-20:1 as eluents. R was collected. f The eluent with a pH of 0.2-0.4 was evaporated to dryness under reduced pressure, and the concentrate obtained was compound III. (2) All compounds III and K3PO4 obtained in step (1) above were dissolved in N,N-dimethylformamide. Tetra(triphenylphosphine)palladium was added under argon protection, and the mixture was heated at 100-150°C for 20-30 hours. After the reaction was completed, the mixture was quenched with water and extracted with ethyl acetate. After drying with anhydrous sodium sulfate, the solution was concentrated under reduced pressure to 1-10% of its original volume. The concentrate was subjected to silica gel column chromatography with petroleum ether as the eluent, and R was collected. f The eluent with a pH of 0.2-0.4 was evaporated to dryness under reduced pressure to obtain compound I; In formula II, R 1 The radicals are hydrogen, methyl, methoxy, bromine, chlorine, iodine, phenyl, benzyl, trifluoromethyl, and ester; R 2 The radicals are hydrogen, methyl, methoxy, bromine, chlorine, iodine, phenyl, benzyl, trifluoromethyl, or ester; X is O or NH; R in Formula III and Formula I 1 R 2 X and X are the same as in equation II.

4. The method as described in claim 3, characterized in that, In step (1), the molar ratio of compound II to sodium tert-butoxide is 1:1-5; the molar ratio of compound II to N-phenylbis(trifluoromethanesulfonyl)imide is 1:1-5; and the volume of tetrahydrofuran used is 5-15 mL / mmol based on the amount of compound II.

5. The method as described in claim 3, characterized in that, In step (2), the ratio of potassium phosphate to compound II is 1-5:1; the ratio of tetra(triphenylphosphine)palladium to compound II is 0.1-1:1; and the volume of N,N-dimethylformamide is 5-15 mL / mmol based on the amount of compound II.

6. The application of the heteroatom helicene compound of claim 1 in the preparation of circularly polarized luminescent materials.

7. A circularly polarized luminescent material prepared from the heteroatom helicene compound of claim 1.

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