A porphyrin-based covalent organic polymer, preparation method and application thereof in detecting water content of organic solvents

Abstract

The invention discloses a porphyrin-based covalent organic polymer and a preparation method and application thereof. The covalent organic polymer has a structure shown in formula I: #imgabs0# The porphyrin-based covalent organic polymer is prepared by Schiff base reaction of 5,10,15-tris(4-aminophenyl)porphyrin and 2,5-dimethoxybenzene-1,4-diformaldehyde. The porphyrin-based covalent organic polymer of the invention has a novel structure, broadens the types of porphyrin monomers of porphyrin-based covalent organic polymers, has good ultraviolet absorption and fluorescence emission properties, and the porphyrin-based covalent organic polymer material can simply, reliably and highly sensitively detect the water content in an organic solvent. In addition, the porphyrin-based covalent organic polymer provided by the invention is expected to become a fluorescent probe for the field of analyte detection.

Description

Technical Field

[0001] The invention belongs to the technical field of functional material preparation, in particular to a porphyrin-based covalent organic polymer, a preparation method and application thereof in detecting the water content of an organic solvent. Background Art

[0002] Detecting the water content in organic solvents is of great significance in chemical reactions and industrial production processes. In organic synthesis, the presence of water in the solvent will quench reactions that are sensitive to water and reduce the yield, such as lithiation, Friedel-Crafts reaction, Grignard reaction, and Witting reaction. In the petroleum industry, determining the water content of water-in-oil emulsions is crucial for crude oil processing and transportation.

[0003] Traditional methods for detecting water content in organic solvents include Karl Fischer titration, electrochemical and electrophysical methods, and chromatography. These methods have some disadvantages: expensive equipment, complex operations, long time consumption, use of toxic reagents, and susceptibility to electromagnetic interference. With the rapid development of optical technology, fluorescence sensing analysis methods have attracted widespread attention due to their ease of manufacture, high sensitivity and selectivity, low cost, short response time, and low detection limit. In recent years, some small molecule organic compounds, polymers, lanthanide complexes, metal organic framework materials (MOFs), and covalent organic framework materials (COFs) based on fluorescence sensing have been developed into fluorescent sensors for the detection of water content in organic solvents. Therefore, designing new fluorescent probes for detecting water remains a challenging research topic.

[0004] Compared with MOFs and COFs, amorphous covalent organic polymers (COPs) have better thermal and chemical stability, and the preparation methods are relatively simple and diverse, the conditions are mild and easy to control, the structure is designable and functionalized, and they have better application prospects. Covalent organic polymers are widely used in many fields such as gas adsorption and storage, electrochemistry, sensors, and photocatalysis. Porphyrin is a molecule with excellent photoelectrocatalytic effect. Porphyrin-based COPs not only have the excellent photoelectric effect and catalytic performance of porphyrin compounds, but also solve some problems that monomer porphyrins have in practical applications. They have good application prospects in catalysis, photoreaction, bionics, sensing and other fields.

[0005] In existing studies, the porphyrin building monomers used are all tetrasubstituted fully symmetrical molecules such as 5,10,15,20-tetrakis(4-aminophenyl)porphyrin, 5,10,15,20-tetrakis(4-formylphenyl)porphyrin, and 5,10,15,20-tetrakis(4-boronic acid phenyl)porphyrin. The singleness of porphyrin monomers limits the types of porphyrin covalent polymers. Therefore, the development and design of asymmetric porphyrin monomers for the synthesis of porphyrin covalent polymers can not only enrich the diversity of porphyrin-based COPs, but also play an important role in improving their performance in their respective fields. Researchers are constantly committed to the construction of porphyrin-based covalent organic polymers, in the hope that such COPs will be more widely used in the field of fluorescent probes for analyte detection.

[0006] Through searching, no patent publication documents related to the patent application of the present invention have been found. Summary of the invention

[0007] The purpose of the present invention is to overcome the problems existing in the prior art and provide a porphyrin-based covalent organic polymer, a preparation method and an application thereof in detecting the water content of an organic solvent.

[0008] The technical solution adopted by the present invention to solve the technical problem is:

[0009] A porphyrin-based covalent organic polymer having a structure shown in Formula I:

[0010]

[0011] The method for preparing the porphyrin-based covalent organic polymer as described above comprises the following steps:

[0012] (1) 5-[4-(N-tert-Butoxycarbonyl)aminophenyl]dipyrromethane, 2,2'-dipyrrolylmethane and 4-(Boc-amino)benzaldehyde were dissolved in dichloromethane, trifluoroacetic acid was added and reacted for 4 hours, then an oxidant was added and the reaction was continued for 1 hour, and 5,10,15-tris(4-Boc-aminophenyl)porphyrin was separated by silica gel column chromatography;

[0013] (2) dissolving 5,10,15-tris(4-Boc-aminophenyl)porphyrin in chloroform, adding trifluoroacetic acid and reacting at room temperature for 70 minutes, neutralizing with sodium bicarbonate aqueous solution, extracting with dichloromethane, drying the lower organic phase with anhydrous sodium sulfate, filtering and concentrating, and then separating by silica gel column chromatography to obtain 5,10,15-tris(4-aminophenyl)porphyrin;

[0014] (3) 5,10,15-tris(4-aminophenyl)porphyrin (TAPP) and 2,5-dimethoxybenzene-1,4-dicarbaldehyde (DM-CHO) are used as ligands, n-butanol and mesitylene are added thereto, the mixture is ultrasonically treated, and then an acetic acid solution is added to obtain a reaction mixture; the container containing the reaction mixture is subjected to a freeze-degassing-thawing process for three cycles, flame-sealed, reacted at 120° C. for 3 days, cooled, and filtered to obtain a dark solid; the solid obtained above is precipitated, washed, and dried to obtain a porphyrin-based covalent organic polymer (PorMeO-COPs).

[0015] Furthermore, in step (1), the oxidant is 2,3-dichloro-5,6-dicyano-p-benzoquinone;

[0016] Alternatively, in step (1), the molar ratio of 5-[4-(N-tert-butyloxycarbonyl)aminophenyl]dipyrrolylmethane, 2,2'-dipyrrolylmethane, 4-(Boc-amino)benzaldehyde, oxidant and trifluoroacetic acid is 1:1:2:3:1;

[0017] The concentration of 2,2'-dipyrrolylmethane in step (1) is 0.0.005-0.01 mol / L;

[0018] Alternatively, in step (2), the concentration of 5,10,15-tris(4-Boc-aminophenyl)porphyrin in chloroform is 0.002-0.003 mol / L;

[0019] Alternatively, in step (2), the volume ratio of chloroform to trifluoroacetic acid is 2:1.

[0020] Furthermore, in step (3), the molar ratio of 5,10,15-tris(4-aminophenyl)porphyrin to 2,5-dimethoxybenzene-1,4-dicarbaldehyde is 2:3;

[0021] Alternatively, in step (3), the concentration of 5,10,15-tris(4-aminophenyl)porphyrin in the mixed solution is 0.01-0.015 mol / L;

[0022] Alternatively, in step (3), the volume ratio of n-butanol, mesitylene and acetic acid is 1:0.5:0.1;

[0023] Alternatively, the washing conditions in step (3) are: Soxhlet extraction with tetrahydrofuran and acetone for 24 hours respectively;

[0024] Alternatively, the specific conditions for drying in step (3) are: drying at 80° C. for 12 h.

[0025] The porphyrin-based covalent organic polymer described above is used for detecting the water content of organic solvents.

[0026] A method for detecting the water content of an organic solvent using the porphyrin-based covalent organic polymer as described above, the method comprising the following steps:

[0027] The porphyrin-based covalent organic polymer is ground and accurately weighed, and a porphyrin-based covalent organic polymer dispersion is prepared with an ultra-dry organic solvent, and different amounts of water are added to observe changes in fluorescence intensity.

[0028] Furthermore, the ultra-dry organic solvent is: methanol, ethanol, acetone or N,N-dimethylformamide;

[0029] Furthermore, the concentration of the porphyrin-based covalent organic polymer in the porphyrin-based covalent organic polymer dispersion is 0.4 mg mL -1 , 0.3mg mL -1 , 0.3mg mL -1 and 0.18 mg mL -1 ;

[0030] Alternatively, the excitation wavelengths of the fluorescence are 362 nm, 362 nm, 380 nm and 370 nm, and the emission wavelengths are 462 nm, 455 nm, 456 nm and 466 nm, respectively.

[0031] Furthermore, the detection limits of the porphyrin-based covalent organic polymer for trace water content in organic solvents are: 0.026% for methanol, 0.032% for ethanol, 0.014% for acetone, and 0.054% for N,N-dimethylformamide.

[0032] The use of the porphyrin-based covalent organic polymer as described above as well as in the preparation of fluorescent probes.

[0033] The beneficial effects achieved by the present invention are:

[0034] 1. The porphyrin-based covalent organic polymer of the present invention has a novel structure, broadens the types of porphyrin monomers of porphyrin-based covalent organic polymers, has good ultraviolet absorption and fluorescence emission properties, and the porphyrin-based covalent organic polymer material can simply, reliably and highly sensitively detect the water content in an organic solvent. In addition, the porphyrin-based covalent organic polymer provided by the present invention is expected to become a fluorescent probe for the field of analyte detection.

[0035] 2. The synthesis process of the method of the present invention is simple, the conditions are easy to control, the prepared material has good thermal stability and chemical stability, and the work efficiency is improved.

[0036] 3. The porphyrin-based covalent organic polymer material prepared by the method of the present invention is very sensitive in fluorescence sensing detection and is easy to operate, and can quickly detect the water content in organic solvents.

[0037] 4. When the porphyrin-based covalent organic polymer of the present invention is used in the detection of water content in organic solvents, 5,10,15-tris(4-aminophenyl)porphyrin and 2,5-dimethoxybenzene-1,4-dicarboxaldehyde are reacted by Schiff base to prepare the covalent organic polymer. The covalent organic polymer prepared by this method uses porphyrin as a connecting unit, has high thermal stability, and has microporous properties. The covalent organic polymer of the present invention can accurately and quantitatively detect trace water in organic solvents (methanol, ethanol, acetone, N,N-dimethylformamide) through fluorescence enhancement, and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 is the H NMR spectrum of 5,10,15-tris(4-aminophenyl)porphyrin in the present invention;

[0039] Figure 2 It is a solid-state NMR carbon spectrum of the porphyrin-based covalent organic polymer material of the present invention;

[0040] Figure 3 is the thermogravimetric diagram of the porphyrin-based covalent organic polymer material of the present invention; Figure 3 It can be seen that the material of the present invention has good thermal stability;

[0041] Figure 4 The infrared spectrum of 5,10,15-tris(4-aminophenyl)porphyrin, 2,5-dimethoxybenzene-1,4-dicarboxaldehyde and porphyrin-based covalent organic polymer materials in the present invention;

[0042] Figure 5 is the N2 adsorption isotherm of the porphyrin-based covalent organic polymer material of the present invention; the specific surface area and pore volume of the material are calculated to be 624 m 2 g -1 and 0.41cm 3 g -1 ;

[0043] Figure 6 This is a pore size distribution diagram of the porphyrin-based covalent organic polymer material of the present invention; it can be seen from the figure that the pore size of the material of the present invention is about 1.269nm;

[0044] Figure 7 This is a graph showing the change in fluorescence peak intensity of the porphyrin-based covalent organic polymer material of the present invention in a methanol solvent as the water content increases;

[0045] Figure 8 This is a graph showing the change in fluorescence peak intensity of the porphyrin-based covalent organic polymer material of the present invention in an ethanol solvent as the water content increases;

[0046] Fig. 9This is a graph showing the change in fluorescence peak intensity of the porphyrin-based covalent organic polymer material of the present invention in an acetone solvent as the water content increases;

[0047] Fig.10 This is a graph showing the change in fluorescence peak intensity of the porphyrin-based covalent organic polymer material of the present invention in DMF solvent as the water content increases. DETAILED DESCRIPTION

[0048] For a better understanding of the present invention, the present invention is further described in detail below in conjunction with embodiments, but the scope of protection claimed by the present invention is not limited to the scope represented by the embodiments.

[0049] The raw materials used in the present invention, unless otherwise specified, are all conventional commercially available products. The methods used in the present invention, unless otherwise specified, are all conventional methods in the art. The quality of each substance used in the present invention is the conventional quality.

[0050] A porphyrin-based covalent organic polymer having a structure shown in Formula I:

[0051]

[0052] The method for preparing the porphyrin-based covalent organic polymer as described above comprises the following steps:

[0053] (1) 5-[4-(N-tert-Butoxycarbonyl)aminophenyl]dipyrromethane, 2,2'-dipyrrolylmethane and 4-(Boc-amino)benzaldehyde were dissolved in dichloromethane, trifluoroacetic acid was added and reacted for 4 hours, then an oxidant was added and the reaction was continued for 1 hour, and 5,10,15-tris(4-Boc-aminophenyl)porphyrin was separated by silica gel column chromatography;

[0054] (2) dissolving 5,10,15-tris(4-Boc-aminophenyl)porphyrin in chloroform, adding trifluoroacetic acid and reacting at room temperature for 70 minutes, neutralizing with sodium bicarbonate aqueous solution, extracting with dichloromethane, drying the lower organic phase with anhydrous sodium sulfate, filtering and concentrating, and then separating by silica gel column chromatography to obtain 5,10,15-tris(4-aminophenyl)porphyrin;

[0055] (3) 5,10,15-tris(4-aminophenyl)porphyrin (TAPP) and 2,5-dimethoxybenzene-1,4-dicarbaldehyde (DM-CHO) are used as ligands, n-butanol and mesitylene are added thereto, the mixture is ultrasonically treated, and then an acetic acid solution is added to obtain a reaction mixture; the container containing the reaction mixture is subjected to a freeze-degassing-thawing process for three cycles, flame-sealed, reacted at 120° C. for 3 days, cooled, and filtered to obtain a dark solid; the solid obtained above is precipitated, washed, and dried to obtain a porphyrin-based covalent organic polymer (PorMeO-COPs).

[0056] Preferably, the oxidant in step (1) is 2,3-dichloro-5,6-dicyano-p-benzoquinone;

[0057] Alternatively, in step (1), the molar ratio of 5-[4-(N-tert-butyloxycarbonyl)aminophenyl]dipyrrolylmethane, 2,2'-dipyrrolylmethane, 4-(Boc-amino)benzaldehyde, oxidant and trifluoroacetic acid is 1:1:2:3:1;

[0058] The concentration of 2,2'-dipyrrolylmethane in step (1) is 0.005-0.01 mol / L;

[0059] Alternatively, in step (2), the concentration of 5,10,15-tris(4-Boc-aminophenyl)porphyrin in chloroform is 0.002-0.003 mol / L;

[0060] Alternatively, in step (2), the volume ratio of chloroform to trifluoroacetic acid is 2:1.

[0061] Preferably, in step (3), the molar ratio of 5,10,15-tris(4-aminophenyl)porphyrin to 2,5-dimethoxybenzene-1,4-dicarbaldehyde is 2:3;

[0062] Alternatively, in step (3), the concentration of 5,10,15-tris(4-aminophenyl)porphyrin in the mixed solution is 0.01-0.015 mol / L;

[0063] Alternatively, in step (3), the volume ratio of n-butanol, mesitylene and acetic acid is 1:0.5:0.1;

[0064] Alternatively, the washing conditions in step (3) are: Soxhlet extraction with tetrahydrofuran and acetone for 24 hours respectively;

[0065] Alternatively, the specific conditions for drying in step (3) are: drying at 80° C. for 12 h.

[0066] The porphyrin-based covalent organic polymer described above is used for detecting the water content of organic solvents.

[0067] A method for detecting the water content of an organic solvent using the porphyrin-based covalent organic polymer as described above, the method comprising the following steps:

[0068] The porphyrin-based covalent organic polymer is ground and accurately weighed, and a porphyrin-based covalent organic polymer dispersion is prepared with an ultra-dry organic solvent, and different amounts of water are added to observe changes in fluorescence intensity.

[0069] Preferably, the ultra-dry organic solvent is: methanol, ethanol, acetone or N,N-dimethylformamide;

[0070] Preferably, the concentration of the porphyrin-based covalent organic polymer in the porphyrin-based covalent organic polymer dispersion is 0.4 mg mL -1 , 0.3mg mL -1 , 0.3mg mL -1 and 0.18 mg mL -1 ;

[0071] Alternatively, the excitation wavelengths of the fluorescence are 362 nm, 362 nm, 380 nm and 370 nm, and the emission wavelengths are 462 nm, 455 nm, 456 nm and 466 nm, respectively.

[0072] Preferably, the detection limits of the porphyrin-based covalent organic polymer for trace water content in organic solvents are: 0.026% for methanol, 0.032% for ethanol, 0.014% for acetone, and 0.054% for N,N-dimethylformamide.

[0073] The use of the porphyrin-based covalent organic polymer as described above as well as in the preparation of fluorescent probes.

[0074] Specifically, the relevant preparation and detection are as follows:

[0075] Example 1: A porphyrin-based covalent organic polymer includes triaminoporphyrin and methoxybenzaldehyde as building blocks to synthesize COPs materials: the covalent organic polymer has a structure shown in Formula I:

[0076]

[0077] The preparation method of the above-mentioned porphyrin-based covalent organic polymer comprises the following steps:

[0078] Weigh 5-[4-(N-tert-butyloxycarbonyl)aminophenyl]dipyrrolylmethane (337 mg, 1 mmol), 2,2'-dipyrrolylmethane (146 mg, 1 mmol), and 4-(Boc-amino)benzaldehyde (442 mg, 2 mmol) into a round-bottom flask, add 200 mL of dichloromethane, then add 80 uL of trifluoroacetic acid, react at room temperature for 4 h, add 2,3-dichloro-5,6-dicyanobenzoquinone (680 mg, 3 mmol) and continue stirring for 1 h. Purify by column chromatography (dichloromethane: ethyl acetate = 30:1 as eluent) to obtain the target product 5,10,15-tris(4-Boc-aminophenyl)porphyrin. 1 H NMR (400MHz, CDCl3) δ10.19(s,1H),9.32(d,J=4.6Hz,2H),9.04(d,J=4.6Hz,2H),8.90(dd,J=10.5,4.8Hz,4H),8.16(d,J=8.3Hz,4H),8 .12(d,J=8.3Hz,2H),7.79(d,J=8.2Hz,4H),7.75(d,J=8.4Hz,2H),6.86(s,2H),6.84(s,1H),1.66(s,18H),1.64(s,9H),-3.01(s,2H).

[0079] In a 100 mL round-bottom flask, 5,10,15-tris(4-Boc-aminophenyl)porphyrin (50 mg, 0.058 mmol) was added, and then completely dissolved with 20 mL of chloroform, placed in an ice bath, 10 mL of TFA was slowly added dropwise, and reacted at room temperature for 70 min. After the reaction was completed, the reaction solution was transferred to a 500 mL beaker, sodium bicarbonate was added for neutralization, and extracted with dichloromethane, the lower layer of solvent was collected, dried with anhydrous sodium sulfate, filtered, and spin-dried, and finally separated and purified by column chromatography (eluent: dichloromethane: tetrahydrofuran = 5:1) to obtain 17 mg of purple solid 5,10,15-tris(4-aminophenyl)porphyrin, with a yield of 52%. 1 HNMR (400MHz, DMSO) δ10.38(s,1H),9.52(d,J=4.6Hz,2H),9.05(d,J=4.6Hz,2H),8.93(dd,J=9.8,4.8Hz,4H),7.89(d,J= 8.2Hz,4H),7.85(d,J=8.3Hz,2H),7.03(d,J=8.3Hz,4H),6.99(d,J=8.3Hz,2H),5.60(s,2H),5.58(s,1H),-2.97(s,2H).

[0080] Weigh 5,10,15-tris(4-aminophenyl)porphyrin (0.02mmol, 11.67mg) and 2,5-dimethoxybenzene-1,4-dicarboxaldehyde (0.03mmol, 5.83mg) into a 5.0mL ampoule, add 1.0mL of n-butanol and 0.5mL of mesitylene to the reaction system, and ultrasonicate for 10min until all solids are dissolved. Add 0.1mL of 6M acetic acid to the system and ultrasonicate for 2min. The freeze-degassing-thawing process is cycled three times and flame sealed. The treated system is placed in an oven and reacted at 120℃ for 3 days. After the reaction is completed, the prepared materials are extracted with tetrahydrofuran and acetone Soxhlet for 24h respectively; the materials are washed and placed in a vacuum oven at 80℃ for 12h to obtain porphyrin-based COPs materials.

[0081] Example 2: Characterization of properties of porphyrin-based organic polymers.

[0082] Figure 1 They are respectively the H NMR spectra of monomer (5,10,15-tris(4-aminophenyl)porphyrin), Figure 2 It is the carbon NMR spectrum of the porphyrin-based covalent organic polymer. The peak at 152.02 ppm corresponds to the chemical shift of C on C=N. Figure 3 This is the thermogravimetric test diagram of porphyrin-based covalent organic polymer, which shows that the material has good thermal stability. Figure 4 This is the infrared spectrum of 5,10,15-tris(4-aminophenyl)porphyrin, 2,5-dimethoxybenzene-1,4-dicarboxaldehyde and porphyrin-based covalent organic polymer. The infrared spectrum of porphyrin-based covalent organic polymer is at 1628cm -1 The characteristic peak of stretching vibration of imine bond (C=N) appears at Figure 5 is the N2 adsorption isotherm, which belongs to the first type of adsorption curve, indicating that the material has a microporous structure. By calculation, the specific surface area and pore volume of the material are 624m 2 g -1 and 0.41cm 3 g -1 . Figure 6 Further calculations based on density functional theory showed that the pore size of this material is 1.269 nm.

[0083] The results of carbon nuclear magnetic resonance spectrum and infrared characterization show that the porphyrin-based COPs material is successfully prepared in the present invention.

[0084] Example 3: Porphyrin-based covalent organic polymer materials are used to detect the water content in methanol solvent.

[0085] The COPs material prepared in Example 1 was placed in an agate mortar and ground thoroughly to prepare 0.4 mg mL -1Take 0.5 mL of the methanol dispersion and add different volumes of water (0, 2, 5, 7, 10, 20, 40, 60 μL) to make it 1 mL with methanol. Then measure the fluorescence emission spectrum of each solution under a fluorescence spectrophotometer. The excitation wavelength is 362 nm and the emission wavelength is 462 nm. Record the maximum fluorescence emission intensity of each solution. The fluorescence spectrum is shown in the figure below. Figure 7 As shown, the fluorescence intensity of COPs material increases with the increase of water content (v / v%), and there is a linear relationship between water content and fluorescence intensity, which can be used for quantitative detection of trace water. The linear range is 0.2-6%, and the detection limit is 0.026%.

[0086] Example 4: Porphyrin-based covalent organic polymer materials are used to detect the water content in ethanol solvent.

[0087] The COPs material prepared in Example 1 was placed in an agate mortar and ground thoroughly to prepare 0.3 mg mL -1 Take 0.5 mL of the above ethanol dispersion, add different volumes of water (0, 10, 20, 50, 100, 150, 200, 300, 400, 500 μL), dilute to 1 mL with ethanol, and then measure the fluorescence emission spectrum of each solution under a fluorescence spectrophotometer, with an excitation wavelength of 362 nm and an emission wavelength of 455 nm, and record the maximum fluorescence emission intensity of each solution. The fluorescence spectrum is shown in the figure below. Figure 8 As shown, the fluorescence intensity of COPs material increases with the increase of water content (v / v%), and there is a linear relationship between water content and fluorescence intensity, which can be used for quantitative detection of trace water. The linear range is 1-20%, and the detection limit is 0.032%.

[0088] Example 5: Porphyrin-based covalent organic polymer materials are used to detect the water content in acetone solvent.

[0089] The COPs material prepared in Example 1 was placed in an agate mortar and ground thoroughly to prepare 0.3 mg mL -1 Take 0.5 mL of the above acetone dispersion, add different volumes of water (0, 10, 20, 40, 60, 80, 100, 120, 140, 160, 180, 200 μL), dilute to 1 mL with acetone, and then measure the fluorescence emission spectrum of each solution under a fluorescence spectrophotometer, with an excitation wavelength of 380 nm and an emission wavelength of 456 nm, and record the maximum fluorescence emission intensity of each solution. The fluorescence spectrum is shown in the figure below. Fig. 9 As shown, the fluorescence intensity of COPs material increases with the increase of water content (v / v%), and there is a linear relationship between water content and fluorescence intensity, which can be used for quantitative detection of trace water. The linear range is 1-16%, and the detection limit is 0.014%.

[0090] Example 6: Porphyrin-based covalent organic polymer materials are used to detect the water content in N,N-dimethylformamide (DMF) solvent.

[0091] The COPs material prepared in Example 1 was placed in an agate mortar and ground thoroughly to prepare 0.18 mg mL -1 DMF solution, take 0.5mL of the above DMF dispersion, add different volumes of water (0, 20, 30, 40, 60, 70, 90, 100, 140, 170, 200μL), dilute to 1mL with DMF, and then measure the fluorescence emission spectrum of each solution under a fluorescence spectrophotometer, with an excitation wavelength of 370nm and an emission wavelength of 466nm, and record the maximum fluorescence emission intensity of each solution. The fluorescence spectrum is shown in the figure below. Fig.10 As shown, the fluorescence intensity of COPs material increases with the increase of water content (v / v%), and there is a linear relationship between water content and fluorescence intensity, which can be used for quantitative detection of trace water. The linear range is 2-10%, and the detection limit is 0.054%.

[0092] It can be concluded from the above examples that the detection limits of the quantitative detection method of the present invention for trace water content in organic solvents are: the detection limit of methanol is 0.026%, the detection limit of ethanol is 0.032%, the detection limit of acetone is 0.014%, and the detection limit of N,N-dimethylformamide is 0.054%. It shows that the fluorescent probe prepared by the present invention has high sensitivity to trace water in organic solvents, and the quantitative detection method of the present invention has the advantages of convenience, high efficiency, sensitivity and low detection limit, and can be used to quantitatively determine trace water in organic solvents in batches and efficiently.

[0093] Although the embodiments of the present invention are disclosed for illustrative purposes, those skilled in the art will appreciate that various substitutions, changes and modifications are possible without departing from the spirit and scope of the present invention and the appended claims. Therefore, the scope of the present invention is not limited to the contents disclosed in the embodiments.

Claims

1. A porphyrin-based covalent organic polymer, characterized in that: The covalent organic polymer has a structure shown in Formula I:

2. The method for preparing a porphyrin-based covalent organic polymer according to claim 1, wherein: The method comprises the following steps: (1) 5-[4-(N-tert-butyloxycarbonyl)aminophenyl]dipyrrolylmethane, 2,2'-dipyrrolylmethane, and 4-(Boc-amino)benzaldehyde were dissolved in dichloromethane, trifluoroacetic acid was added to react for 4 hours, and then an oxidant was added to continue the reaction for 1 hour, and 5,10,15-tris(4-Boc-aminophenyl)porphyrin was separated by silica gel column chromatography; (2) dissolving 5,10,15-tris(4-Boc-aminophenyl)porphyrin in chloroform, adding trifluoroacetic acid and reacting at room temperature for 70 minutes, neutralizing with sodium bicarbonate aqueous solution, extracting with dichloromethane, drying the lower organic phase with anhydrous sodium sulfate, filtering and concentrating, and then separating by silica gel column chromatography to obtain 5,10,15-tris(4-aminophenyl)porphyrin; (3) 5,10,15-tris(4-aminophenyl)porphyrin (TAPP) and 2,5-dimethoxybenzene-1,4-dicarboxaldehyde are used as ligands, n-butanol and mesitylene are added thereto, the mixed solution is ultrasonically treated, and then an acetic acid solution is added to obtain a reaction mixture; the container containing the reaction mixture is subjected to a freeze-degassing-thawing process for three cycles, flame-sealed, reacted at 120° C. for 3 days, cooled, and filtered to obtain a dark solid; the solid obtained above is precipitated, washed, and dried to obtain a porphyrin-based covalent organic polymer.

3. The method for preparing a porphyrin-based covalent organic polymer according to claim 2, characterized in that: In the step (1), the oxidant is 2,3-dichloro-5,6-dicyano-p-benzoquinone; Alternatively, in step (1), the molar ratio of 5-[4-(N-tert-butyloxycarbonyl)aminophenyl]dipyrrolylmethane, 2,2'-dipyrrolylmethane, 4-(Boc-amino)benzaldehyde, oxidant and trifluoroacetic acid is 1:1:2:3:1; The concentration of 2,2'-dipyrrolylmethane in step (1) is 0.005-0.01 mol / L; Alternatively, in step (2), the concentration of 5,10,15-tris(4-Boc-aminophenyl)porphyrin in chloroform is 0.002-0.003 mol / L; Alternatively, in step (2), the volume ratio of chloroform to trifluoroacetic acid is 2:

1.

4. The method for preparing a porphyrin-based covalent organic polymer according to claim 2 or 3, characterized in that: In the step (3), the molar ratio of 5,10,15-tris(4-aminophenyl)porphyrin to 2,5-dimethoxybenzene-1,4-dicarbaldehyde is 2:3; Alternatively, in step (3), the concentration of 5,10,15-tris(4-aminophenyl)porphyrin in the mixed solution is 0.01-0.015 mol / L; Alternatively, in step (3), the volume ratio of n-butanol, mesitylene and acetic acid is 1:0.5:0.1; Alternatively, the washing conditions in step (3) are: Soxhlet extraction with tetrahydrofuran and acetone for 24 hours respectively; Alternatively, the specific conditions for drying in step (3) are: drying at 80° C. for 12 h.

5. Use of the porphyrin-based covalent organic polymer as claimed in claim 1 in detecting the water content of an organic solvent.

6. A method for detecting the water content of an organic solvent using the porphyrin-based covalent organic polymer as claimed in claim 1, characterized in that: The method comprises the following steps: The porphyrin-based covalent organic polymer is ground and accurately weighed, and a porphyrin-based covalent organic polymer dispersion is prepared with an ultra-dry organic solvent, and different amounts of water are added to observe changes in fluorescence intensity.

7. The method according to claim 6, characterized in that: The ultra-dry organic solvent is methanol, ethanol, acetone or N,N-dimethylformamide.

8. The method according to claim 6, characterized in that: The concentrations of the porphyrin-based covalent organic polymer in the porphyrin-based covalent organic polymer dispersion are 0.4 mg mL -1 , 0.3mg mL -1 , 0.3mg mL -1 and 0.18 mg mL -1 ; Alternatively, the excitation wavelengths of the fluorescence are 362 nm, 362 nm, 380 nm and 370 nm, and the emission wavelengths are 462 nm, 455 nm, 456 nm and 466 nm, respectively.

9. The method according to any one of claims 6 to 8, characterized in that: The detection limits of the porphyrin-based covalent organic polymer for trace water content in organic solvents are: the detection limit of methanol is 0.026%, the detection limit of ethanol is 0.032%, the detection limit of acetone is 0.014%, and the detection limit of N,N-dimethylformamide is 0.054%.

10. Use of the porphyrin-based covalent organic polymer according to claim 1 as and / or in the preparation of a fluorescent probe.

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