阅读说明：本技术 一种具有大斯托克斯位移bodipy类近红外荧光染料及其制备方法 (BODIPY near-infrared fluorescent dye with large Stokes shift and preparation method thereof ) 是由 徐海军 王怡 李鹏飞 于 2021-08-06 设计创作，主要内容包括：本发明涉及一种具有大斯托克斯位移BODIPY类近红外荧光染料及其制备方法,采用BODIPY衍生物(I)与对二甲氨基苯甲醛为原料在对甲苯磺酸和哌啶催化作用下发生Knoevenagel缩合反应得到,其化学结构式如式(II)所示。该制备方法反应步骤简单、反应条件温和、选择性较好。该荧光染料具有高的摩尔消光系数和大的斯托克斯位移,且其最强电子吸收波长为703nm、最大荧光发射波长为813nm。在生物标记、近红外荧光成像、光电材料等领域具有广泛的应用前景。(The invention relates to a BODIPY near-infrared fluorescent dye with large Stokes displacement and a preparation method thereof. The preparation method has the advantages of simple reaction steps, mild reaction conditions and good selectivity. The fluorescent dye has high molar extinction coefficient and large Stokes shift, and the strongest electron absorption wavelength of the fluorescent dye is 703nm and the maximum fluorescence emission wavelength of the fluorescent dye is 813 nm. Has wide application prospect in the fields of biological marking, near infrared fluorescence imaging, photoelectric materials and the like.)

1. A BODIPY near infrared fluorescent dye with large Stokes shift is characterized in that the structural formula is shown as the formula (II):

2. the preparation method of BODIPY near infrared fluorescent dye (II) with large Stokes shift as claimed in claim 1, which is characterized by comprising the following steps: under the anhydrous condition, adding the BODIPY derivative (I) and p-dimethylaminobenzaldehyde into dry toluene according to the molar ratio of 1: 8-10, adding p-toluenesulfonic acid and piperidine, stirring and heating, controlling the temperature at 115-125 ℃, reacting for 4-6 hours, finishing the reaction, cooling to room temperature, extracting with dichloromethane, drying, and carrying out separation and purification by silica gel column chromatography to obtain the BODIPY near-infrared fluorescent dye (II) with large Stokes shift, wherein the chemical reaction formula of the process is as follows:

3. the method for preparing BODIPY near-infrared fluorescent dye with large Stokes shift according to claim 2, wherein the ratio of the volume of toluene, the volume of piperidine and the amount of BODIPY derivative (I) substance is 20-25 mL: 1.5-2 mL: 0.5 mmol.

4. The preparation method of the BODIPY near-infrared fluorescent dye with large Stokes shift according to claim 2, wherein the molar ratio of the BODIPY derivative (I) to p-dimethylaminobenzaldehyde is 1: 8-10.

5. The BODIPY near infrared fluorescent dye with large Stokes shift as set forth in claim 1, wherein the molar absorption coefficient is greater than 2.0 x 10⁵cm^-1mol^-1L, the strongest electron absorption wavelength of the fluorescent material is 703nm, the maximum fluorescence emission wavelength of the fluorescent material is 813nm, and the Stokes shift reaches 110 nm.

Technical Field

The invention belongs to the technical field of organic synthesis, fluorescent dyes and fine chemical engineering, and particularly relates to a BODIPY near-infrared fluorescent dye with large Stokes shift and a preparation method thereof.

Background

The development and application of organic small-molecule fluorescent dyes have attracted extensive attention, and classical fluorescent dyes include cyanine dyes, BODIPY dyes, rhodamine, coumarin, fluorescein and the like. However, most fluorescent dyes have absorption and emission wavelengths less than 650nm, and thus have poor tissue penetration ability, severe autofluorescence, and strong phototoxicity, which results in severe limitations on the application of the fluorescent dyes in cell, tissue, and in vivo fluorescence imaging techniques. The fluorescent dye with the excitation and emission wavelengths in the near infrared region (NIR, 650-900nm) has stronger penetrating power to cells, tissues and living bodies, is less interfered by background fluorescence in the living bodies, and has less light damage to biological samples, so that the near infrared fluorescent dye is better applied to the imaging of the cells, the tissues and the living bodies of the living bodies.

The excellent fluorescent dye not only needs to have larger molar extinction coefficient and high fluorescence quantum yield, but also needs to have the advantages of larger Stokes shift, wavelength in the near infrared region and the like. On the one hand, a larger stokes shift reduces the effect of fluorescence self-quenching; on the other hand, the excitation wavelength and the emission wavelength are in the near infrared region, which will increase the signal-to-noise ratio in biological imaging. Therefore, the design and preparation of the novel near-infrared fluorescent dye with the large Stokes shift and better photochemical and photophysical properties have important significance.

BODIPY fluorescent dyes are chemically stable, have a large molar extinction coefficient, have a high fluorescence quantum yield, and attract close attention of researchers in the fields of fluorescent labels, fluorescent probes, organic electroluminescent devices (OLEDs), biotechnology, solar cells, and the like. In addition, the parent structure of the BODIPY fluorescent dye has better chemical modifiability, and the wavelength of the BODIPY fluorescent dye is easy to adjust to a near infrared region by introducing different conjugated groups. However, the BODIPY fluorescent dye usually has smaller Stokes shift (most of the Stokes shift is less than 50nm), thereby greatly limiting the application of the BODIPY fluorescent dye in the aspects of biological labeling, fluorescence imaging, fluorescent probes and the like.

Aiming at the defects of the prior art, the invention introduces a strong electron-donating group (p-dimethylamino styrene) to a BODIPY derivative (I) with an electron-withdrawing group (4-fluoro-3-methyl-styrene) through a Knoevenagel condensation reaction to form an effective electron push-pull structure, thereby synthesizing the BODIPY near-infrared fluorescent dye with large Stokes shift. The method effectively solves the problem of small Stokes shift of the BODIPY fluorescent dye, so that the near-infrared fluorescent dye can improve the detection sensitivity and accuracy, reduce the fluorescence self-quenching, and increase the signal-to-noise ratio of biological imaging. The fluorescent probe has wide application prospect in the fields of biological markers, near-infrared fluorescence imaging, photoelectric materials and the like.

Disclosure of Invention

The purpose of the invention is as follows: aiming at the defects in the prior art, the invention aims to provide a BODIPY near-infrared fluorescent dye with large Stokes shift and a preparation method thereof.

The technical scheme is as follows: in order to achieve the purpose of the invention, the invention adopts the technical scheme that:

the invention relates to a BODIPY near-infrared fluorescent dye with large Stokes shift and a preparation method thereof, which is characterized in that the near-infrared fluorescent dye has a structural formula shown in a formula (II):

a BODIPY near infrared fluorescent dye with large Stokes shift and a preparation method thereof, the steps are as follows:

(1) adding a BODIPY derivative (I), p-dimethylaminobenzaldehyde and p-toluenesulfonic acid into a round-bottom flask provided with a Dean-stark device, dissolving the mixture in 20-25 mL of toluene and 1.5-2 mL of piperidine, heating the reaction mixture to 115-125 ℃, refluxing, and reacting for 4-6 hours. Wherein the molar ratio of the BODIPY derivative (I) to the dimethylaminobenzaldehyde is 1: 8-10.

(2) The reaction mixture is cooled to room temperature, dichloromethane is extracted and washed, an organic layer is dried by anhydrous sodium sulfate, the organic solvent is removed by reduced pressure distillation, the residue is separated by silica gel column chromatography, and an eluent is dichloromethane-petroleum ether (v: v ═ 3: 2), so that a dark green solid product BODIPY near infrared fluorescent dye is obtained.

The specific chemical reaction formula is as follows:

in the step (1), the molar ratio of the BODIPY derivative (I) to the dimethylaminobenzaldehyde is 1: 8-10.

In the step (1), the ratio of the volume of the toluene, the piperidine and the BODIPY derivative (I) to the amount of the substance is 20-25 mL: 1.5-2 mL: 0.5 mmol.

In the step (1), the catalyst is p-toluenesulfonic acid and piperidine.

In the above step (2), the eluent for silica gel column chromatography was dichloromethane-petroleum ether (v: v ═ 3: 2).

The invention has the advantages of

Compared with the prior art, the BODIPY near infrared fluorescent dye with large Stokes shift and the preparation method thereof have the advantages that: (1) the preparation method is simple and easy to implement, and the problems of more synthesis steps, expensive catalyst, high difficulty and the like of the BODIPY near-infrared fluorescent dye with large Stokes shift are solved; (2) the near infrared fluorescent dye has high molar extinction coefficient (larger than 2.0 multiplied by 10)⁵cm^-1mol^-1L), the maximum electron absorption wavelength of which is 703nm and the maximum fluorescence emission wavelength of which is 813 nm; (3) the near-infrared fluorescent dye has large Stokes displacement which reaches 110 nm; the method is favorable for improving the detection sensitivity and accuracy of the near-infrared fluorescent dye, reducing the fluorescence self-quenching of the near-infrared fluorescent dye, and increasing the signal to noise ratio of biological imaging, so that the method has wide application prospects in the fields of biological markers, near-infrared fluorescent imaging, photoelectric materials and the like.

Drawings

FIG. 1 is a graph of the UV-VIS absorption spectrum of a BODIPY-based near infrared fluorescent dye (II) with a large Stokes shift;

FIG. 2 is a graph of fluorescence emission spectra of a BODIPY-based near infrared fluorescent dye (II) with large Stokes shift;

FIG. 3 is a MALDI-TOF MASS diagram of a BODIPY-based near infrared fluorescent dye (II) having a large Stokes shift.

Detailed Description

The invention is further described below with reference to the specific drawings.

By using¹H-NMR, MALDI-TOF-MS characterize and confirm the structure of the BODIPY near infrared fluorescent dye (II) with large Stokes shift, and the spectral properties are determined by using UV-Vis spectrum and fluorescence spectrometer. The detection instrument is as follows: bruker ARX600 NMR Spectrometer (deuterated chloroform as solvent), Shimadzu UV-3100 UV-visible spectrophotometer (scanning range 300-900 nm, optical path slit 2nm), fluorescence spectrum was measured with American Amico Bowman Series 2 Luminescence Spectrometer.

Example 1 preparation of BODIPY-based near Infrared fluorescent dye (II) with Large Stokes Shift

A dry round bottom flask was equipped with a Dean-Stark apparatus under anhydrous conditions, BODIPY type derivative (I) (303mg, 0.5mmol), p-dimethylaminobenzaldehyde (745mg, 5mmol) and p-toluenesulfonic acid (43mg, 0.25mmol) were dissolved in 25mL of toluene and 2mL of piperidine, heated to 120 ℃ under reflux, and reacted for 6 hours. Cooled to room temperature, extracted with dichloromethane, washed with water, the organic layers were combined, the organic solvent was evaporated under reduced pressure, and the residue was purified by silica gel column chromatography using dichloromethane-petroleum ether (v: v ═ 3: 2) to give a dark green solid product, BODIPY type near infrared fluorescent dye (II) (87mg, 20%).¹H NMR(600MHz，CDCl₃)：δ7.68(d，J＝16.2Hz，2H)，7.51(d，J＝6.0Hz，2H)，7.46-7.41(m，2H)，7.30(d，J＝16.2Hz，2H)，7.16(s，2H)，7.06-7.02(m，4H)，6.92-6.86(m，6H)，6.59(d，J＝7.8Hz，4H)，5.75(d，J＝15.6Hz，2H)，2.99(s，12H)，2.59(s，3H)，2.36(s，6H)，2.15(s，6H).MALDI-TOF-MS：calculated for C₅₆H₅₃BF₄N₄：868.4299；found：868.425[M]⁺。

UV-vis: 370nm, 622nm, 703nm (FIG. 1); emission wavelet: 813nm (FIG. 2).

Example 2 preparation of BODIPY-based near Infrared fluorescent dye (II) with Large Stokes Shift

Similar to example 1, except that the BODIPY derivative (I) in this example was reacted with p-dimethylaminobenzaldehyde at a molar ratio of 1: 6; the reaction temperature was controlled at 115 ℃ and the reaction time was 4 hours. Yield: 15 percent.

Example 3 preparation of BODIPY-based near Infrared fluorescent dye (II) with Large Stokes Shift

Similar to example 1, except that the BODIPY derivative (I) in this example was reacted with p-dimethylaminobenzaldehyde at a molar ratio of 1: 6; the reaction temperature was controlled at 125 ℃ and the reaction time was 6 hours. Yield: 17 percent.

Example 4 ultraviolet-visible absorption Spectroscopy of BODIPY near Infrared fluorescent dye (II) solution with Large Stokes Shift

Dissolving BODIPY near infrared fluorescent dye (II) with large Stokes shift in dichloromethane, and configuring to have concentration of 1 × 10^-5The ultraviolet-visible absorption spectrum of the methylene chloride solution was measured. FIG. 1 shows the UV-VIS absorption spectrum of the near-IR fluorescent dye (II) solution prepared in example 1 of the present invention.

Example 5 fluorescence emission spectra of solutions of BODIPY-based near-infrared fluorescent dyes (II) with large Stokes' shift

Dissolving BODIPY near infrared fluorescent dye (II) with large Stokes shift in dichloromethane, and configuring to have concentration of 1 × 10^-5And measuring the fluorescence emission spectrum of the dichloromethane solution with mol/L. FIG. 2 shows the fluorescence spectrum of the near-infrared fluorescent dye (II) solution prepared in example 1 of the present invention.