A fluoroborylpyrrole derivative and its preparation method and application

Abstract

This patent application discloses a fluoroborylpyrrole derivative and its preparation method and application. The fluoroborylpyrrole derivative is based on fluoroborylpyrrole (BODIPY), with a tetrahydroxy organic group represented by 1,2,4,5-benzene tetraphenol as a bridge bond, and a boron-oxygen coordination bond as a dimer construction core. By introducing a suitable electron donor, a multifunctional photosensitizer with strong ultraviolet-visible light absorption ability, high excitation wavelength selectivity, and the ability to show fluorescence recovery, excited triplet state population and free radical generation after light excitation at a specific wavelength is synthesized. The fluoroborylpyrrole derivative photosensitizer has been confirmed to produce long-lived fluoroborylpyrrole cationic free radicals under ultraviolet light irradiation through a laser flash photolysis instrument, and can be used in photopolymerization and photocatalysis.

Description

Technical Field

[0001] The present patent application relates to the technical field of organic photosensitizer materials, and more specifically, to a fluoroborane pyrrole derivative and a preparation method and application thereof. Background Art

[0002] Traditional triplet photosensitizers usually refer to organic transition metal complex photosensitizers. However, the use of precious metals cannot avoid the consideration of their limited earth reserves, high cost, environmental unfriendliness, potential biological toxicity and other disadvantages. In recent years, organic photosensitizers that do not contain transition metals have become the focus of research at home and abroad. Among the common organic chromophores, fluoroborylpyrrole has attracted more and more attention in the past two or three decades. The dye has a series of unique photophysical properties such as strong visible light absorption ability, good solubility, high photostability, high fluorescence quantum yield, sharp fluorescence spectrum peak, easy structural modification, and multiple modifiable sites.

[0003] Photocatalysis is one of the important application directions of organic photosensitizer materials at present. It is a technology that uses light to trigger organic redox reactions with the help of photosensitizers. It can purify pollutants or synthetic substances. In the context of the era of energy transformation and energy revolution, its good characteristics of being green, clean, environmentally friendly and sustainable are highlighted.

[0004] However, to date, although there have been many reports on organic photosensitizer materials designed based on fluoroborane pyrrole, the application research in the field of photocatalysis has been slow. This is because the realization of photocatalysis in past reports is basically based on the excited triplet state, and the relationship between its properties and photocatalytic performance is still unclear, resulting in the realization of photocatalytic applications requiring a lot of preliminary screening work. If the photosensitizer can directly produce free radicals after light excitation, it will be able to overcome this problem to a large extent. However, there are currently few reports on this type of photoinduced free radical phenomenon, and it is difficult to control the properties of free radicals, which is reflected in the need to take into account the effective generation of photoinduced free radicals, and to ensure that the photosensitizer has a certain light stability, and can also produce free radicals with a certain lifespan to meet application requirements.

[0005] Therefore, developing an organic photosensitizer material with controllable photoinduced free radical phenomenon and long-lived free radicals is a technical problem that needs to be solved urgently by those skilled in the art.

[0006] Patent application content

[0007] In order to overcome at least one problem of the above-mentioned prior art, the present patent application provides a fluoroboryl pyrrole derivative that can be used as a photosensitizer. The fluoroboryl pyrrole derivative photosensitizer can produce an excited triplet state under visible light irradiation, and can additionally show fluorescence recovery and free radical generation under ultraviolet light irradiation, and the generated fluoroboryl pyrrole cationic free radicals have the characteristics of long life. It can overcome the problems of the above-mentioned prior art that the photo-induced free radical phenomenon is rare and the free radical properties are difficult to control.

[0008] Another object of the present patent application is to provide a method for preparing the above-mentioned fluoroboryl pyrrole derivatives.

[0009] Another object of the present patent application is to provide the application of the above-mentioned fluoroboryl pyrrole derivatives in fluorescence sensing, photopolymerization or photocatalysis.

[0010] In order to solve the above technical problems, the technical solution adopted by this patent application is:

[0011] A fluoroboryl pyrrole derivative can be used as a photosensitizer, and has a chemical structure as shown in formula (I):

[0012] Formula (I)

[0013] Wherein, R can be selected from any one of the following structural formulas a to i:

[0014]

[0015] The tetrahydroxy organic group bridge bond may be selected from one of j to r in the following structural formula:

[0016]

[0017] Preferably, R is selected from any one of the following structures:

[0018] This patent application also provides a method for preparing the above-mentioned fluoroboryl pyrrole derivative, which comprises the following steps:

[0019] S1: Aromatic aldehyde, trifluoroacetic acid, dimethylpyrrole, a catalyst, and a solvent are mixed, and an aryl dipyrrole is prepared in one pot by a dehydration condensation reaction and an oxidative dehydrogenation reaction, wherein the structure of the aromatic aldehyde is

[0020] S2: The aryl dipyrrole prepared in step S1, triethylamine, trifluoroboron ether and solvent are mixed to prepare fluoroboron pyrrole by boron-nitrogen complex reaction, wherein the aryl dipyrrole compound has the structural formula: The structural formula of the fluoroboryl pyrrole is

[0021] S3: mixing the fluoroborane pyrrole, aluminum chloride, 1,2,4,5-pyrophentetraphenol, acetonitrile and solvent obtained in step S2, and obtaining the target product, compound of formula (I), through nucleophilic substitution reaction.

[0022] Preferably, in step S1, the molar ratio of the aromatic aldehyde, trifluoroacetic acid, dimethylpyrrole and catalyst is (1-1.2):(0.3-0.5):(3.0-4.0):(1-1.2).

[0023] Preferably, in step S2, the molar ratio of aryl dipyrrole, triethylamine and trifluoroboron ether is (1-1.2): (30-35): (1.5-2.0).

[0024] More preferably, in step S2, the molar ratio of aryldipyrrole, triethylamine and trifluoroboron ether is 1.0:3.0:1.5.

[0025] Preferably, in step S2, the solvent is dichloromethane.

[0026] Preferably, in step S2, the boron-nitrogen complexation reaction temperature is an ice bath, and the reaction time is 2 to 4 hours.

[0027] More preferably, in step S2, the boron-nitrogen complexation reaction temperature is 0° C., and the reaction time is 3 hours.

[0028] The deboronation and nitrogenation complexation reaction described in the present patent application is carried out in an inert gas, and the inert gas is preferably nitrogen.

[0029] In the patent application, after the deboronation and nitrogen complexation reaction is completed, post-treatment is also included, and the post-treatment is concentration and separation in sequence. Specifically, after the reaction is completed, the reaction solvent is removed under reduced pressure. The crude product after reduced pressure concentration is purified by column chromatography (silica gel, dichloromethane / petroleum ether) to obtain an orange solid target product.

[0030] Preferably, in step S3, the molar ratio of fluoroborane, aluminum chloride, 1,2,4,5-pyrophenone and acetonitrile is (1-1.2): (2.5-3): (0.3-0.4): (130-170).

[0031] More preferably, in step S3, the molar ratio of fluoroborane, aluminum chloride, 1,2,4,5-pyrophenone and acetonitrile is 1.0:2.5:0.35:150.

[0032] Preferably, in step S3, the solvent is dichloromethane.

[0033] Preferably, in step S3, the reaction temperature is firstly reflux temperature, the reaction time is 10 to 20 minutes and then the reaction temperature is room temperature, the reaction time is 30 to 40 minutes.

[0034] More preferably, in the nucleophilic substitution reaction in step S3, the reaction temperature of fluoroboryl pyrrole, aluminum chloride and solvent is 40°C and the reaction time is 15 minutes; after cooling to room temperature, the acetonitrile solution of 1,2,4,5-pyrophenone is slowly dripped, the reaction temperature is 25°C and the reaction time is 30 minutes.

[0035] The nucleophilic substitution reaction described in the present patent application is carried out in an inert gas, and the inert gas is preferably nitrogen.

[0036] In the present patent application, after the nucleophilic substitution reaction is completed, post-treatment is also included, and the post-treatment is extraction, drying, concentration, and separation in sequence. Specifically, after the reaction is completed, the reaction solvent is removed under reduced pressure, and extracted with dichloromethane, washed three times with a saturated sodium chloride aqueous solution, and finally dried with anhydrous sodium sulfate. The crude product after reduced pressure concentration is eluted and purified by column chromatography (basic alumina, dichloromethane / petroleum ether) to obtain a dark green solid target product.

[0037] Preferably, in step S1, the catalyst is tetrachlorobenzoquinone, the reaction temperature is room temperature, and the reaction time is 6 to 12 hours.

[0038] More preferably, the reaction temperature of the dehydration condensation reaction and the oxidative dehydrogenation reaction is 25° C., the reaction time of the dehydration condensation reaction is 4 hours, and the reaction time of the oxidative dehydrogenation reaction is 4 hours.

[0039] Preferably, in step S1, the solvent is selected from dichloromethane.

[0040] The dehydration condensation reaction and oxidative dehydrogenation reaction described in the present patent application are carried out in an inert gas, and the inert gas is preferably nitrogen.

[0041] In the present patent application, after the dehydration condensation reaction and the oxidative dehydrogenation reaction are completed, post-treatment is also included, and the post-treatment is extraction, drying, concentration, and separation in sequence. Specifically, after the reaction is completed, the reaction solvent is removed under reduced pressure, extracted with dichloromethane, washed three times with a saturated sodium chloride aqueous solution, and finally dried with anhydrous sodium sulfate. The crude product after reduced pressure concentration is purified by column chromatography (basic alumina, dichloromethane / petroleum ether) to obtain a brown solid target product.

[0042] Preferably, in step S2, the reaction temperature is an ice bath and the reaction time is 2 to 4 hours.

[0043] Preferably, in step S3, the reaction temperature is reflux temperature and room temperature, and the reaction time is 10 to 20 minutes and 30 to 40 minutes.

[0044] This patent application also provides the application of the above-mentioned fluoroboryl pyrrole derivatives in fluorescence sensing, photopolymerization or photocatalysis.

[0045] Compared with the prior art, the beneficial effects of this patent application are:

[0046] The fluoroborylpyrrole derivatives provided in this patent application can be used as photosensitizers. They are based on fluoroborylpyrrole (BODIPY), with tetrahydroxy organic groups represented by 1,2,4,5-benzeneteterol as bridge bonds, and with boron-oxygen coordination bonds as dimer construction cores. By introducing suitable electron donors, they are synthesized to have strong ultraviolet-visible light absorption ability, high excitation wavelength selectivity, and the ability to show fluorescence recovery, excited triplet population, and free radical generation after light excitation at a specific wavelength. Therefore, they can be used as multifunctional photosensitizers. The applications of fluoroborylpyrrole derivatives in fluorescence sensing, photopolymerization, or photocatalysis have significant economic value. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 The compound DBDP-Ph prepared in Example 1 1 HMNR diagram.

[0048] Figure 2 The mass spectrum of the compound DBDP-Ph prepared in Example 1.

[0049] Figure 3 The compound DBDP-An prepared in Example 2 1 HMNR diagram.

[0050] Figure 4 The mass spectrum of the compound DBDP-An prepared in Example 2.

[0051] Figure 5 The absorption spectra of the compounds DBDP-Ph, DBDP-An, BDP-Ph and BDP-An prepared in Examples 1, 2, 4 and 6 respectively in dichloromethane solution.

[0052] Figure 6 The fluorescence emission spectra of the compounds DBDP-Ph and DBDP-An prepared in Examples 1 and 2, respectively, in dichloromethane solution.

[0053] Figure 7 This is a nanosecond transient absorption spectrum of the compound DBDP-Ph prepared in Example 1 in a dichloromethane solution.

[0054] Figure 8This is the nanosecond transient absorption spectrum of the compound DBDP-An prepared in Example 2 in a dichloromethane solution.

[0055] Fig. 9 The nanosecond transient absorption spectra of the compound DBDP-Ph prepared in Example 1 were measured at excitation wavelengths of 503 nm and 355 nm respectively.

[0056] Fig.10 The nanosecond transient absorption spectra of the compound DBDP-An prepared in Example 2 were measured at excitation wavelengths of 503 nm and 355 nm respectively.

[0057] Fig.11 This is a nanosecond kinetic decay curve of the compound DBDP-Ph prepared in Example 1 tested at an excitation wavelength of 355 nm.

[0058] Fig.12 This is a nanosecond kinetic decay curve of the compound DBDP-An prepared in Example 2 tested at an excitation wavelength of 355 nm. DETAILED DESCRIPTION

[0059] The embodiments of the present patent application will be described in detail below in conjunction with the examples, but those skilled in the art will appreciate that the following examples are only used to illustrate the present patent application and should not be considered to limit the scope of the present patent application. If the specific conditions are not specified in the examples, they are carried out according to the normal conditions or the conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0060] It should be noted that:

[0061] In this patent application, unless otherwise specified, all implementation methods and preferred implementation methods mentioned herein can be combined with each other to form a new technical solution.

[0062] In this patent application, unless otherwise specified, each reaction or operation step can be carried out sequentially or in a sequential manner. Preferably, the reaction method herein is carried out sequentially.

[0063] Unless otherwise specified, the professional and scientific terms used herein are the same as those familiar to those skilled in the art. In addition, any method or material similar or equivalent to the described content may also be applied to this patent application.

[0064] This patent application discloses a fluoroboryl pyrrole derivative which can be used as a photosensitizer and has a chemical structure shown in formula (I):

[0065] Formula (I)

[0066] Wherein, R can be selected from any one of the following structural formulas a to i:

[0067]

[0068] The tetrahydroxy organic group bridge bond may be selected from one of j to r in the following structural formula:

[0069]

[0070] The fluoroborylpyrrole derivative disclosed in this patent application can be used as a photosensitizer, which is based on fluoroborylpyrrole (BODIPY), with a tetrahydroxy organic group represented by 1,2,4,5-benzeneteterol as a bridge bond, and a boron-oxygen coordination bond as a dimer construction core, and a multifunctional photosensitizer with strong ultraviolet-visible light absorption ability, high excitation wavelength selectivity, and the ability to show fluorescence recovery, excited triplet state population (i.e., excited triplet state generation, after the molecule is excited, a series of transitions finally reach the triplet state) and free radical generation after light excitation at a specific wavelength is synthesized by introducing a suitable electron donor. The application of fluoroborylpyrrole derivatives in fluorescence sensing, photopolymerization or photocatalysis has significant economic value.

[0071] The applicant of the present patent also provides a method for preparing the above-mentioned fluoroboryl pyrrole derivatives.

[0072] Next, the preparation method of the fluoroboryl pyrrole derivatives in this patent application is described in detail with specific examples.

[0073] Example 1

[0074] A fluoroboryl pyrrole derivative having a molecular structure as described in the following formula, named DBDP-Ph:

[0075]

[0076] The preparation method of the fluoroboryl pyrrole derivative DBDP-Ph comprises the following steps:

[0077] Step 1: Preparation of 2-[(3,5-dimethyl-2H-pyrrol-2-ylidene)benzyl]-3,5-dimethyl-1H-pyrrole

[0078] A solution of benzaldehyde (254.4 mg, 2.4 mmol) in dichloromethane (DCM for short, 250 mL) was replaced with argon and bubbling with argon for 15 min. Then dimethylpyrrole (0.96 mL, 9.6 mmol) and trifluoroacetic acid (0.1 mL) were added. The mixture was stirred at room temperature for 4 hours in a darkened state. Then tetrachlorobenzoquinone (603 mg, 2.4 mmol) was added and stirred at room temperature for 4 hours in a darkened state. After the reaction was completed, the reaction solvent was removed under reduced pressure, extracted with dichloromethane (30 mL), washed three times with a saturated aqueous NaCl solution, and finally dried over anhydrous sodium sulfate. After concentration under reduced pressure, 278 mg of a light brown solid was obtained by elution purification using column chromatography (basic alumina, dichloromethane / petroleum ether, 1 / 4, v / v). (Yield: 42%)

[0079] The reaction equation is as follows:

[0080]

[0081] Step 2: Preparation of phenylfluoroborylpyrrole:

[0082] The dichloromethane (150mL) solution of step 1 target product (182.4mg, 0.66mmol) was replaced with argon, and argon was blown for 15min. After the temperature dropped and stabilized using an ice bath, triethylamine (3mL, 21.8mmol) was added, and trifluoroborated ether (5mL) was slowly added dropwise using a syringe. The mixture was stirred for 3 hours in an ice bath under shading. After concentration under reduced pressure, column chromatography (silica gel, dichloromethane / petroleum ether, 1 / 3, v / v) was used for elution purification to obtain 171mg orange solid (yield: 80%).

[0083] The reaction equation is as follows:

[0084]

[0085] Step 3: Preparation of DBDP-Ph

[0086] A solution of phenylfluoroboryl (74 mg, 0.229 mmol) in dichloromethane (30 mL) was replaced with argon. Aluminum chloride (76.4 mg, 0.573 mmol) was added. The mixture was stirred at 40 ° C for 15 minutes. After cooling to room temperature, a solution of 1,2,4,5-benzenetetrol (13 mg, 0.0916 mmol) in acetonitrile (5 mL) was slowly added dropwise through a syringe. The mixture was stirred at room temperature for 30 minutes. After the reaction was completed, the reaction solvent was removed under reduced pressure, extracted with dichloromethane (100 mL), washed three times with a saturated NaCl aqueous solution, and finally dried over anhydrous sodium sulfate. Column chromatography (basic alumina, dichloromethane / petroleum ether, 1 / 1, v / v) was used for elution purification to obtain 39 mg of dark green solid (yield: 48%).

[0087] The reaction equation is as follows:

[0088]

[0089] The fluoroboryl pyrrole derivative photosensitizer DBDP-Ph is based on fluoroboryl pyrrole (BODIPY), with 1,2,4,5-benzenetetraphenol containing tetrahydroxy organic groups as bridge bonds, and boron-oxygen coordination bonds as dimer construction cores. By introducing suitable electron donor phenyl groups, a multifunctional photosensitizer material with strong ultraviolet-visible light absorption ability, high excitation wavelength selectivity, and the ability to exhibit fluorescence recovery, excited triplet population, and free radical generation after specific wavelength light excitation is synthesized.

[0090] Example 2

[0091] A fluoroborylpyrrole derivative having a molecular structure as described in the following formula, named DBDP-An:

[0092]

[0093] The preparation method of the fluoroboryl pyrrole derivative DBDP-An comprises the following steps:

[0094] Step 1: Preparation of 2-[9-anthryl(3,5-dimethyl-2H-pyrrole-2-ylidene)methyl]-3,5-dimethyl-1H-pyrrole:

[0095] A solution of 9-anthracenecarboxaldehyde (494.9 mg, 2.4 mmol) in dichloromethane (250 mL) was replaced with argon and bubbling with argon for 15 min. Then dimethylpyrrole (0.96 mL, 9.6 mmol) and trifluoroacetic acid (0.1 mL) were added. The mixture was stirred at room temperature for 4 hours in a darkened state. Then tetrachlorobenzoquinone (603 mg, 2.4 mmol) was added and stirred at room temperature for 4 hours in a darkened state. After the reaction was completed, the reaction solvent was removed under reduced pressure, extracted with dichloromethane (30 mL), washed three times with a saturated aqueous solution of NaCl, and finally dried over anhydrous sodium sulfate. After concentration under reduced pressure, 434 mg of a light brown solid was obtained by elution purification using column chromatography (basic alumina, dichloromethane / petroleum ether, 1 / 4, v / v). (Yield: 48%)

[0096] The reaction equation is as follows:

[0097]

[0098] Step 2: Preparation of anthracene fluoroboryl pyrrole:

[0099] The dichloromethane (150mL) solution of step 1 target product (248.5mg, 0.66mmol) was replaced with argon, and argon was blown for 15min. After the temperature dropped and stabilized in an ice bath, triethylamine (3mL, 21.8mmol) was added, and trifluoroborated ether (5mL) was slowly added dropwise using a syringe. The mixture was stirred for 3 hours in an ice bath under light shielding. After concentration under reduced pressure, column chromatography (silica gel, dichloromethane / petroleum ether, 1 / 3, v / v) was used for elution purification to obtain 252mg orange solid (yield: 90%).

[0100] The reaction equation is as follows:

[0101]

[0102] Step 3: Preparation of DBDP-An

[0103] The dichloromethane (30mL) solution of anthracene fluoroboryl pyrrole (97mg, 0.229mmol) was replaced with argon. Aluminum chloride (76.4mg, 0.573mmol) was added. The mixture was stirred at 40°C for 15 minutes. After cooling to room temperature, a solution of 1,2,4,5-pyroquinone (13mg, 0.0916mmol) in acetonitrile (5mL) was slowly added dropwise through a syringe. The mixture was stirred at room temperature for 30 minutes. After the reaction was completed, the reaction solvent was removed under reduced pressure, extracted with dichloromethane (100mL), washed three times with a saturated NaCl aqueous solution, and finally dried over anhydrous sodium sulfate. Column chromatography (basic alumina, dichloromethane / petroleum ether, 1 / 1, v / v) was used for elution purification to obtain 43mg of dark green solid (yield: 41%).

[0104] The reaction equation is as follows:

[0105]

[0106] The fluoroboryl pyrrole derivative photosensitizer DBDP-An is based on fluoroboryl pyrrole (BODIPY), with 1,2,4,5-benzenetetraphenol containing tetrahydroxy organic groups as bridge bonds, and boron-oxygen coordination bonds as dimer construction cores. By introducing a suitable electron donor anthracene group, a multifunctional photosensitizer material with strong ultraviolet-visible light absorption ability, high excitation wavelength selectivity, and the ability to exhibit fluorescence recovery, excited triplet state population, and free radical generation after light excitation at a specific wavelength is synthesized.

[0107] Example 3

[0108] This embodiment provides a fluoroboryl pyrrole derivative BDP-Ph, and its preparation method is similar to that of Example 1. The molecular structure of the fluoroboryl pyrrole derivative is as follows:

[0109]

[0110] Example 4

[0111] This embodiment provides a fluoroboryl pyrrole derivative, named BDP-Pn, and its preparation method is similar to that of Example 1. The molecular structure of the fluoroboryl pyrrole derivative is as follows:

[0112]

[0113] Example 5

[0114] This embodiment provides a fluoroboryl pyrrole derivative, and its preparation method is similar to that of embodiment 2. The molecular structure of the fluoroboryl pyrrole derivative is as follows:

[0115]

[0116] Example 6

[0117] This example provides a fluoroboryl pyrrole derivative, named BDP-An, and its preparation method is similar to that of Example 2. The molecular structure of the fluoroboryl pyrrole derivative is as follows:

[0118]

[0119] Structural characterization and performance testing

[0120] Figure 1 is the NMR spectrum of compound DBDP-Ph. Figure 1 It can be seen that its characteristic wave number (ppm) is 1H NMR (400MHz, Chloroform-d): δ7.49–7.47 (m, 6H), 7.31–7.29 (m, 4H), 6.45 (s, 2H), 5.94 (s, 4H), 2.17 (s, 12H), 1.35 (s, 12H). The chemical shift corresponds to the hydrogen atoms on the compound DBDP-Ph, and the molecular hydrogen spectrum peaks can correspond to the target product one by one, and the quantity is reasonable. The instrument for the nuclear magnetic spectrum is a Bruker 400MHz superconducting nuclear magnetic resonance instrument, and the solvent is deuterated chloroform. It can be seen from the nuclear magnetic spectrum that the product obtained in Example 1 is DBDP-Ph.

[0121] Figure 2 The mass spectrum of the compound DBDP-Ph. The mass spectrometer was tested by using a Thermo Fisher Q Exactive ultra-high resolution quadrupole combined electrostatic field orbital trap liquid-mass spectrometer, and DBDP-Ph was dissolved in dichloromethane to prepare a solution with a concentration of 1 mg / ml. It can be seen that the relative molecular mass of DBDP-Ph is 710.32172, which is consistent with the relative molecular mass of the synthesized fluoroboryl pyrrole derivative. Through the above mass spectrum, it can be further known that the product obtained in Example 1 is DBDP-Ph.

[0122] Figure 3 is the NMR spectrum of compound DBDP-An. Figure 3 It can be seen that its characteristic wave number (ppm) is 1 H NMR (400MHz, Chloroform-d): δ8.60 (s, 2H), 8.08 (t, 8H, J = 8.0Hz), 7.54-7.51 (m, 4H), 7.48-7.44 (m, 4H), 6.63 (s, 2H), 5.91 (s, 4H), 2.30 (s, 12H), 0.67 (s, 12H). The chemical shift corresponds to the hydrogen atoms on the compound DBDP-An, and the molecular hydrogen spectrum peaks can correspond to the target product one by one, and the quantity is reasonable. The instrument for the nuclear magnetic spectrum is a Bruker 400MHz superconducting nuclear magnetic resonance instrument, and the solvent is deuterated chloroform. It can be seen from the above nuclear magnetic spectrum that the product obtained in Example 2 is DBDP-An.

[0123] Figure 4 The mass spectrum of the compound DBDP-An is shown in Figure 2. The mass spectrum was measured by using a Thermo Fisher Q Exactive ultra-high resolution quadrupole combined electrostatic field orbital trap liquid-mass spectrometer, and DBDP-An was dissolved in dichloromethane to form a solution with a concentration of 1 mg / ml for testing. It can be seen that the relative molecular mass of DBDP-An is 910.38391, which is consistent with the relative molecular mass of the synthesized fluoroboryl pyrrole derivative. From the above mass spectrum, it can be further known that the product obtained in Example 2 is DBDP-An.

[0124] Figure 5This is the absorption spectrum of compounds BDP-Ph, BDP-An, DBDP-Ph and DBDP-An in dichloromethane solution measured by Shimadzu UV-2700 ultraviolet visible spectrophotometer. Figure 5 It can be seen that the dichloromethane solutions of BDP-Ph, BDP-An, DBDP-Ph and DBDP-An show relatively strong and sharp absorption peaks at a wavelength of 500nm, especially the absorption intensity of compound BDP-Ph is greater than 1, indicating that the fluoroboryl pyrrole derivatives of this patent application have strong ultraviolet-visible light absorption ability.

[0125] Figure 6 The fluorescence emission spectra of the obtained compounds DBDP-Ph and DBDP-An were tested by Edinburgh FLS980 at an excitation wavelength of 470 nm. Figure 6 As shown, the emission of compounds DBDP-Ph and DBDP-An are 524 nm and 518 nm, respectively.

[0126] Figure 7 The irradiation time-dependent fluorescence emission spectrum of the obtained compound DBDP-Ph was tested for Edinburgh FLS980 at an excitation wavelength of 355nm. As the UV irradiation time increases, the fluorescence emission gradually increases. This shows that the fluoroboryl pyrrole derivative DBDP-Ph can additionally show fluorescence recovery under UV irradiation.

[0127] Figure 8 The irradiation time-dependent fluorescence emission spectrum of the obtained compound DBDP-An was tested for Edinburgh FLS980 at an excitation wavelength of 355nm. As the UV irradiation time increases, the fluorescence emission gradually increases. This shows that the fluoroboryl pyrrole derivative DBDP-An can additionally show fluorescence recovery under UV irradiation.

[0128] Fig. 9 The nanosecond transient absorption spectra of the compound DBDP-Ph obtained by testing Edinburgh LP980 at excitation wavelengths of 503nm and 355nm respectively. Fig. 9 As shown, the compound DBDP-Ph can generate fluoroborylpyrrole cation free radicals under 355nm wavelength light excitation (that is, there is a very obvious upward peak at 540nm, and 540nm is the fluoroborylpyrrole cation free radical BDP ·+ The fluoroborylpyrrole derivative DBDP-Ph has an absorption peak at 503 nm, but does not generate fluoroborylpyrrole cation free radicals under the excitation of a 503 nm wavelength light source (i.e., there is no upward peak at 540 nm). Therefore, when the fluoroborylpyrrole derivative DBDP-Ph in the present patent application is used as a photosensitizer, it can be stable when the excitation wavelength is greater than 400 nm, and generate fluoroborylpyrrole cation free radicals when the excitation wavelength is less than 400 nm, proving that the fluoroborylpyrrole derivative DBDP-Ph has high excitation wavelength selectivity.

[0129] Fig.10 The nanosecond transient absorption spectra of the compound DBDP-An obtained by Edinburgh LP980 at excitation wavelengths of 503nm and 355nm. Fig.10 As shown, DBDP-An compound can generate fluoroborylpyrrole cation free radicals under 355nm wavelength light excitation (that is, there is a very obvious upward peak at 540nm, and 540nm is the fluoroborylpyrrole cation free radical BDP ·+ The fluoroborylpyrrole derivative DBDP-An has an absorption peak at 503 nm, but does not generate fluoroborylpyrrole cation free radicals under the excitation of a 503 nm wavelength light source (i.e., there is no upward peak at 540 nm). Therefore, when the fluoroborylpyrrole derivative DBDP-An in the present patent application is used as a photosensitizer, it can be stable when the excitation wavelength is greater than 400 nm, and generate fluoroborylpyrrole cation free radicals when the excitation wavelength is less than 400 nm, proving that the fluoroborylpyrrole derivative DBDP-An has high excitation wavelength selectivity.

[0130] Fig.11 The nanosecond kinetic decay curve of the compound DBDP-Ph obtained by testing Edinburgh LP980 at an excitation wavelength of 355nm. Fig.11 As shown, the radical lifetime is longer than 3.0 ms. This proves that the fluoroborylpyrrole derivative DBDP-Ph generates long-lived fluoroborylpyrrole-type cation radicals under UV irradiation.

[0131] Fig.12 The nanosecond kinetic decay curve of the compound DBDP-An obtained by testing Edinburgh LP980 at an excitation wavelength of 355nm. Fig.12 As shown, the radical lifetime is longer than 22.5ms. This also proves that the lifetime of the fluoroborylpyrrole cation radical generated by the fluoroborylpyrrole derivative DBDP-An under ultraviolet light is very long.

[0132] In summary, the present patent application discloses a fluoroboryl pyrrole derivative and its preparation method and application. The fluoroboryl pyrrole derivative is based on fluoroboryl pyrrole (BODIPY), with a tetrahydroxy organic group represented by 1,2,4,5-benzeneteterol as a bridge bond, and a boron-oxygen coordination bond as a dimer construction core. By introducing a suitable electron donor, a multifunctional photosensitizer with strong ultraviolet-visible light absorption ability, high excitation wavelength selectivity, and the ability to exhibit fluorescence recovery, excited triplet population, and free radical generation after excitation at a specific wavelength is synthesized.

[0133] The fluoroboryl pyrrole derivative photosensitizer in this patent application has been confirmed to generate long-lived fluoroboryl pyrrole cationic free radicals under ultraviolet light through laser flash photolysis, and can be used in photopolymerization and photocatalysis.

[0134] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiments or examples are included in at least one embodiment or example of this patent application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0135] Although several embodiments of the present patent application have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present patent application, and the scope of the present patent application is defined by the claims and their equivalents.

Claims

1. A fluoroborylpyrrole derivative, which can be used as a photosensitizer, characterized in that: It has the chemical structure shown below: ； DBDP-An ； BDP-Ph ； BDP-Pn ； BDP-An.

2. The method for preparing the fluoroboryl pyrrole derivative according to claim 1, characterized in that: The steps include: S1: Aromatic aldehyde, trifluoroacetic acid, dimethylpyrrole, a catalyst, and a solvent are mixed, and an aryl dipyrrole is prepared in one pot by a dehydration condensation reaction and an oxidative dehydrogenation reaction, wherein the structure of the aromatic aldehyde is ; S2: The aryl dipyrrole obtained in step S1, triethylamine, boron trifluoride etherate and solvent are mixed to obtain fluoroboryl pyrrole by boron-nitrogen complex reaction, wherein the aryl dipyrrole compound has the structural formula: , the structural formula of the fluoroboryl pyrrole is ; S3: mixing the fluoroborane obtained in step S2, aluminum chloride, 1,2,4,5-pyrophentetraphenol, acetonitrile and a solvent, wherein the solvent is dichloromethane, and obtaining DBDP-An through a nucleophilic substitution reaction.

3. The method for preparing the fluoroboryl pyrrole derivative according to claim 2, characterized in that: In step S1, the molar ratio of aromatic aldehyde, trifluoroacetic acid, dimethylpyrrole and catalyst is (1-1.2): (0.3-0.5): (3.0-4.0): (1-1.2).

4. The method for preparing the fluoroboryl pyrrole derivative according to claim 2, characterized in that: In the step S2, the molar ratio of aryl dipyrrole, triethylamine and boron trifluoride ether is (1-1.2): (30-35): (1.5-2.0).

5. The method for preparing the fluoroboryl pyrrole derivative according to claim 2, characterized in that: In step S3, the molar ratio of fluoroborane, aluminum chloride, 1,2,4,5-pyrophenone and acetonitrile is (1-1.2): (2.5-3): (0.3-0.4): (130-170).

6. The method for preparing the fluoroboryl pyrrole derivative according to claim 2, characterized in that: In the step S1, the catalyst is tetrachlorobenzoquinone, the reaction temperature is room temperature, and the reaction time is 6 to 12 hours.

7. The method for preparing the fluoroboryl pyrrole derivative according to claim 2, characterized in that: In step S2, the reaction temperature is an ice bath and the reaction time is 2 to 4 hours.

8. The method for preparing the fluoroboryl pyrrole derivative according to claim 2, characterized in that: In step S3, the reaction temperature is firstly reflux temperature, the reaction time is 10-20 minutes and then the reaction temperature is room temperature, the reaction time is 30-40 minutes.

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