An active C-site alkylated fluorescent diarylethylene organic compound, its preparation method and application

Abstract

This invention discloses a high-fluorescence quantum yield fluorescently lit diarylethylene organic compound alkylated at activated carbon sites and its preparation method. The structure of this high-fluorescence quantum yield fluorescently lit diarylethylene organic compound is shown in general formula (1), where R1 represents an alkyl chain. All fluorescently lit diarylethylene photochromic materials of this invention can achieve visible light-driven open-ring to closed-ring conversion and exhibit extremely high fluorescence quantum yield in the closed-ring form.

Description

Technical Field

[0001] This invention relates to photochromic materials, and particularly to a high-fluorescence quantum yield, fluorescently lit diarylene photochromic material with activated carbon site alkylation. Background Technology

[0002] Fluorescent diarylethylene materials, due to their unique photophysical properties of being non-fluorescent in their open-ring form but fluorescent in their closed-ring form, have been widely used in sensing, gating, anti-counterfeiting, and super-resolution microscopy of biological organisms in recent years, making them a promising class of materials for commercialization. However, most current fluorescent diarylethylene molecules exhibit low fluorescence quantum yields in their closed-ring forms, limiting their application in super-resolution fluorescence imaging. Research in this field has revealed that fluorescent diarylethylene molecules with low fluorescence quantum yields often have methyl groups attached to their activated carbon sites. The introduction of methyl groups leads to deformation of the central cyclohexadiene, increasing the dihedral angle between the two double bonds in the central cyclohexadiene, thus reducing the planarity and rigidity of the closed ring, increasing its non-radiative transition component, and resulting in a lower fluorescence quantum yield. Therefore, changing the molecular design strategy by using long-chain alkyl groups to replace activated carbon sites to develop novel fluorescent diarylethylene molecules with high fluorescence quantum yields is of great significance. Summary of the Invention

[0003] To address the aforementioned problems in existing technologies, a synthetic strategy involving the introduction of long-chain alkyl groups into activated carbon sites is employed. This introduction reduces the deformation of the central cyclohexadiene in the closed-ring structure, decreases the dihedral angle between the two double bonds of the central cyclohexadiene, and improves the molecular planarity and rigidity, thereby ultimately increasing the fluorescence quantum yield of the closed-ring structure. Through this strategy, a high-fluorescence-quantum-yield, fluorescently lit diarylethene photochromic material is obtained.

[0004] The technical solution of the present invention is as follows:

[0005] An organic compound of diarylethene with high fluorescence quantum yield alkylated at activated carbon sites, the structure of which is shown in general formula (1):

[0006]

[0007] R1 is a C2 to C8 alkyl group.

[0008] As a preferred embodiment, R1 in general formula (1) represents one of the following structures:

[0009] -C2H5, -C3H7, -C4H9, -C5H 11 -C6H 13 -C7H 15 ,i-Pr,t-Bu.

[0010] Preferably, the activated carbon-site alkylated high-fluorescence quantum yield fluorescently lit diarylethene organic compound is one of the following specific compounds:

[0011] Wherein, C2H5 represents n-ethyl,

[0012] Wherein, C3H7 represents n-propyl.

[0013] Wherein, C4H9 represents n-butyl.

[0014] Among them, C5H 11 Indicates n-pentyl,

[0015] Among them, C6H 13 Indicates the foundation of self-correction.

[0016] Among them, C7H 15 Indicates positive heptium base,

[0017]

[0018] Preferably, the diarylethene organic compound is compound 1 or 2, with the following structural formula:

[0019]

[0020] The present invention also provides a method for preparing the diarylethylene organic compound, comprising:

[0021] Under an inert atmosphere, 2,3-dibromo-5-methylthiophene and a boric acid compound were dissolved in tetrahydrofuran, and then Pd(PPh3)4 and a saturated potassium carbonate solution were added. The mixture of the above reactants was refluxed for 12–24 h. After the reaction mixture was cooled to room temperature, it was extracted with ethyl acetate, the organic phases were combined, dried over anhydrous Na2SO4, and then evaporated to dryness. The target product was obtained by silica gel column chromatography.

[0022] The reaction formula is as follows:

[0023]

[0024] Preferably, the molar ratio of 2,3-dibromo-5-methylthiophene to boric acid compounds is 1:2.4-2.6, the molar ratio of Pd(PPh3)4 to boric acid compounds is 0.1:0.9-1.1, and the volume ratio of saturated potassium carbonate solution to tetrahydrofuran is 0.5:0.9-1.1.

[0025] Compared with the prior art, the beneficial technical effects of the present invention are as follows:

[0026] The compounds of this invention, on a novel molecular framework, reduce the deformation of the central cyclohexadiene in the closed ring by introducing long-chain alkyl groups at activated carbon sites, thereby decreasing the dihedral angle between the two double bonds of the central cyclohexadiene and improving the molecular planarity and rigidity. This optimized strategy can further dramatically increase the fluorescence quantum yield of the closed ring without affecting the maximum fluorescence emission. Furthermore, the above results have been verified by density functional theory calculations and experiments, demonstrating the excellent application prospects of this novel diarylethene molecule. Detailed Implementation

[0027] The present invention will now be described in detail with reference to the embodiments.

[0028] Example 1: Synthesis of Compound 1:

[0029] Synthesis route:

[0030]

[0031] In a 50 mL double-necked flask, 2,3-dibromo-5-methylthiophene (0.07 g, 0.30 mmol), a boric acid compound (0.23 g, 0.72 mmol), and 10 mL of tetrahydrofuran solution were added sequentially and stirred until dissolved. Then, 5 mL of saturated K₂CO₃ solution and Pd(PPh₃)₄ (0.09 g, 0.08 mmol) were added. The solution was degassed with nitrogen for approximately 15 minutes and then refluxed for 8 hours. After cooling the reaction mixture to room temperature, it was extracted with ethyl acetate, and the combined organic phases were dried over anhydrous Na₂SO₄ and evaporated to dryness. Purification by silica gel column chromatography (DCM / hexane = 1:3) yielded 1 (0.16 g, 84%). 1 H NMR (400MHz, CDCl3): δ[ppm]1.99-1.25(t,6H),2.22-2.27(m,7H),6.63(s,1H),7.30-7.63(m, 6H),7.71-7.79(m,4H),7.90-7.92(m,2H),7.96(m,2H),8.25-8.27(m,1H),8.41(d,J=4Hz,1H); 13C NMR (100MHz, CDCl3): δ[ppm]146.44,138.90,137.38,137.19,135.30,132.12,130.01,129.86,127.64,127.5 6,126.94,126.67,125.38,125.08,122.77,122.23,121.99,121.94,18.1,17.6,15.7,8.61,8.33.HRMS[M+H] + calcd.for C 37 H 30 O4S3:634.1306, found 634.1278.

[0032] Example 2: Synthesis of Compound 2:

[0033] Synthesis route:

[0034]

[0035] In a 50 mL double-necked flask, 2,3-dibromo-5-methylthiophene (0.07 g, 0.30 mmol), a boric acid compound (0.24 g, 0.72 mmol), and 10 mL of tetrahydrofuran solution were added sequentially and stirred until dissolved. Then, 5 mL of saturated K₂CO₃ solution and Pd(PPh₃)₄ (0.09 g, 0.08 mmol) were added. The solution was degassed with nitrogen for approximately 15 minutes and then refluxed for 8 hours. After cooling the reaction mixture to room temperature, it was extracted with ethyl acetate, and the combined organic phases were dried over anhydrous Na₂SO₄ and evaporated to dryness. Purification by silica gel column chromatography (DCM / hexane = 1:3) yielded 2 (0.16 g, 80%). 1 H NMR (400MHz, CDCl3): δ[ppm]1.99-1.25(t,6H),2.21-2.29(m,11H),6.64(s,1H),7.32-7.61(m, 6H),7.70-7.82(m,4H),7.90-7.93(m,2H),7.98(m,2H),8.24-8.26(m,1H),8.42(d,J=4Hz,1H); 13C NMR (100MHz, CDCl3): δ[ppm]148.42,140.38,140.04,136.42,134.91,132.17,129.98,129.84,128.90,127.53,124 .84,124.64,123.73,123.09,121.97,121.94,121.82,118.91,27.7,27.2,19.2,15.8,11.8,8.60,8.28.HRMS[M+H] + calcd.for C 39 H 34 O4S3:662.1619, found 662.1609.

[0036] The vertical absorption energy, oscillator strength, HOMO / LUMO energy level, and band gap between HOMO and LUMO were quantitatively calculated for the open-ring and closed-ring forms of compounds 1 and 2 of the present invention, respectively; the maximum emission, fluorescence quantum yield, fluorescence lifetime, and S1 energy level were tested, and the results are shown in Table 1.

[0037] Table 1: Theoretical calculations and experimental data for molecules 1 and 2

[0038]

[0039]

[0040] The above experimental results show that the closed-ring compounds 1 and 2 of this application have extremely high fluorescence quantum efficiency and can successfully achieve visible light-driven cyclization and high fluorescence quantum yield, which have good application prospects.

[0041] While the invention has been disclosed through embodiments and preferred embodiments, it should be understood that the invention is not limited to the disclosed embodiments. Rather, those skilled in the art will appreciate that it is intended to cover various variations and similar arrangements. Therefore, the scope of the appended claims should be consistent with the broadest interpretation to cover all such variations and similar arrangements.

Claims

1. A diarylethylene organic compound alkylated at activated carbon sites, characterized in that, The structure is shown in general formula (1): In general formula (1), R1 represents one of the following structures: -C2H5, -C3H7, -C4H9, -C5H 11 -C6H 13 -C7H 15 。 2. The diarylethylene organic compound according to claim 1, characterized in that, The diarylethene organic compound is compound 1 or compound 2, with the following structural formula:

3. The application of a diarylethylene organic compound as described in any one of claims 1 to 2 in the preparation of photochromic materials.

4. The application of the diarylethylene organic compound according to claim 3 in the preparation of photochromic materials, characterized in that, The photochromic material is a fluorescent illumination type photochromic material.

5. An anti-counterfeiting ink, characterized in that, Organic compounds containing diarylethene as described in any one of claims 1 to 2.

6. A method for preparing a diarylethylene organic compound as described in any one of claims 1 to 2, characterized in that, include: Under an inert atmosphere, 2,3-dibromo-5-methylthiophene and a boric acid compound were dissolved in tetrahydrofuran, and then Pd(PPh3)4 and a saturated potassium carbonate solution were added. The mixture of the above reactants was refluxed for 12–24 h. After the reaction mixture was cooled to room temperature, it was extracted with ethyl acetate, the organic phases were combined, dried over anhydrous Na2SO4, and then evaporated to dryness. The target product was obtained by silica gel column chromatography. The reaction formula is as follows: R1 represents one of the following structures: -C2H5, -C3H7, -C4H9, -C5H 11 -C6H 13 -C7H 15 。 7. The method for preparing the diarylethylene organic compound according to claim 6, characterized in that, The molar ratio of 2,3-dibromo-5-methylthiophene to boric acid compounds is 1:2.4-2.6, the molar ratio of Pd(PPh3)4 to boric acid compounds is 0.1:0.9-1.1, and the volume ratio of saturated potassium carbonate solution to tetrahydrofuran is 0.5:0.9-1.1.

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