CN111423563A

CN111423563A - For detecting Fe3+Fused heterocyclic conjugated polymer and preparation method and application thereof

Info

Publication number: CN111423563A
Application number: CN202010446544.6A
Authority: CN
Inventors: 蔡雪刁; 董茹; 陈起
Original assignee: Shaanxi Normal University
Current assignee: Shaanxi Normal University
Priority date: 2020-05-25
Filing date: 2020-05-25
Publication date: 2020-07-17
Anticipated expiration: 2040-05-25
Also published as: CN111423563B

Abstract

The invention discloses a method for detecting Fe³⁺The structural unit of the fused heterocyclic conjugated polymer is

R₁Represents

Or

R₂Represents phenyl, C₁～C₈Alkyl-substituted phenyl, halophenyl, C₁～C₃Alkoxy substitutionPhenyl, carbomethoxy or carbethoxy. The polymer is synthesized by utilizing A3-grafting reaction, and has the advantages of multi-component reaction, such as good atom utilization rate, product diversity and the like. Fe³⁺Ion pair synthesized main chain imidazo [2,1-b]The fluorescence of tetrahydrofuran solution of the fused heterocyclic conjugated polymer with a thiazole structure has obvious quenching effect and can be used for Fe in an organic phase³⁺Detection of ions, and of Fe³⁺High ion selectivity and low detection limit.

Description

For detecting Fe3+Fused heterocyclic conjugated polymer and preparation method and application thereof

Technical Field

The invention belongs to the technical field of high molecular polymers, and particularly relates to a novel fused heterocyclic conjugated polymer, specifically to a conjugated polymer with a main chain containing imidazo [2,1-b ]]Thiazole fused heterocycle conjugated polymer, preparation method of polymer and Fe detection method³⁺The use of (1).

Background

The fused heterocyclic conjugated polymer is a novel advanced functional polymer material, and attracts the wide attention of scientists due to the excellent photoelectric activity of the fused heterocyclic conjugated polymer. In the past decades, a series of fused heterocyclic polymers have been developed and studied, such as polymers containing benzodipyrrole, benzofuran, benzothiophene, benzothiadiazole, benzylcarbazole and naphthopyran, poly- (iminocoumarin) and the like. The unique conjugated condensed heterocyclic structure in the polymers endows the polymers with excellent electron transmission performance, so that the polymers can be widely applied to the fields of polymer light-emitting diodes, organic photovoltaic cells, organic field effect transistors, optical sensors and the like.

Of the many fused heterocyclic structures, imidazo [2,1-b ] thiazoles have attracted our attention for their wide range of applications. Imidazole [2,1-b ] thiazole is a nitrogen-containing condensed heterocyclic compound, exists in a plurality of natural products and drug molecules, and has remarkable physiological and pharmacological activities, such as cancer resistance, antibiosis, anxiety resistance and the like. In addition, the compounds are also widely applied to the technical fields of dyes, multifunctional materials, fluorescent probes and the like. However, to date, the successful preparation of polymers containing imidazothiazole groups has not been reported.

In recent years, due to the important role of transition metal ions in living bodies and their influence on the environment, their detection techniques have been the focus of attention. Among them, iron (Fe) is a trace metal element essential to the human body, and is involved in various biological processes of cells and tissues, and plays an important role particularly in processes of hemoglobin synthesis, redox reaction, energy metabolism, and the like. Iron deficiency most commonly causes iron deficiency anemia, leading to dysheme synthesis and, in turn, erythropoiesisThe excessive iron may result in the deposition of iron in various organs of the whole body, such as liver, heart, brain, etc., and thus cause dysfunction of various systems, and there are also great amount of research on Parkinson's disease and Alzheimer's disease related to iron, and Fe content is the important index for drinking water detection³⁺Is one of the important subjects of human research. At present, there are many methods for detecting metal ions, such as electrochemical analysis, atomic spectrometry, ion mass spectrometry, and the like. However, these conventional detection methods have the limitations of poor stability, complex operation, expensive instruments and equipment, etc., and the sample preparation process is also quite complicated.

Disclosure of Invention

The invention aims to provide a method for detecting Fe³⁺The fused heterocyclic conjugated polymer has the advantages of simple operation, short response time, higher stability and selectivity, and the preparation method and the application of the polymer.

In view of the above object, the structural units of the fused heterocyclic conjugated polymer used in the present invention are as follows:

in the formula R₁Represents

Any one of, R₂Represented by phenyl, C₁～C₈Alkyl-substituted phenyl, halophenyl, C₁～C₃The alkoxy is substituted for any one of phenyl, carbomethoxy and carbethoxy.

The preparation method of the fused heterocyclic conjugated polymer comprises the following steps: adding a bisazine monomer shown as a formula I, a monomer shown as a formula II and containing two aldehyde groups, an alkyne monomer shown as a formula III, copper salt and alkali into dimethyl sulfoxide, carrying out polymerization reaction under the protection of inert gas and stirring at 70-90 ℃, and extracting, drying and dialyzing after the reaction is finished to obtain a fused heterocyclic conjugated polymer;

in the formula III, R₃Represents hydrogen or carboxyl.

In the preparation method, the copper salt is any one of cuprous chloride, cuprous iodide and cuprous bromide; the alkali is any one of anhydrous potassium carbonate and anhydrous sodium carbonate.

In the preparation method, the molar ratio of the bisazine monomer to the monomer containing two aldehyde groups to the alkyne monomer is preferably 1: 1.0-3.0: 2.0-5.0, and the molar ratio of the bisazine monomer to the cuprous iodide and the anhydrous potassium carbonate is preferably 1: 0.02-0.5: 2.0-5.0.

The fused heterocyclic conjugated polymer is used for detecting Fe³⁺The detection method comprises dissolving the conjugated polymer in tetrahydrofuran or water to obtain 1.0 × 10^-6mol/L of polymer solution, and then adding Fe with different concentrations³⁺Standard sample, detecting fluorescence intensity of system, and plotting Fe with different concentrations³⁺Maximum fluorescence intensity of the corresponding system with Fe³⁺A standard curve of concentration change; then testing and adding Fe to be tested³⁺The fluorescence intensity of the system in the sample solution can be determined according to the fluorescence intensity and the standard curve equation³⁺The content of (a).

The invention has the following beneficial effects:

1. the invention utilizes A3-Coupling reaction to synthesize a fused heterocyclic conjugated polymer, and the method is similar to the traditional method: compared with Suzuki cross-coupling reaction, Still reaction, Kumada reaction, Sonogashira reaction and the like, the synthesis method disclosed by the invention has the advantages of commercialized raw materials, simplicity in operation and no need of multi-step reaction and intermediate purification.

2、Fe³⁺The ion has obvious quenching effect on the fluorescence of tetrahydrofuran solution of the fused heterocyclic conjugated polymer synthesized by the invention, and can be used for Fe in an organic phase³⁺The detection of ions is simple to operate, has short response time and can be used for detecting Fe³⁺High ion selectivity and low detection limit.

Drawings

FIG. 1 shows the fluorescence intensity of polymer P1 as a function of Fe³⁺Fluorescence spectrum of concentration change.

FIG. 2 is the relative fluorescence intensity of Polymer P1 as a function of Fe³⁺Linear dependence of concentration change.

FIG. 3 shows the fluorescence intensity of polymer P2 as a function of Fe³⁺Fluorescence spectrum of concentration change.

FIG. 4 is the relative fluorescence intensity of Polymer P2 as a function of Fe³⁺Linear dependence of concentration change.

FIG. 5 shows the fluorescence intensity of Polymer P3 as a function of Fe³⁺Fluorescence spectrum of concentration change.

FIG. 6 is the relative fluorescence intensity of Polymer P3 as a function of Fe³⁺Linear dependence of concentration change.

FIG. 7 shows the fluorescence intensity of polymer P5 as a function of Fe³⁺Fluorescence spectrum of concentration change.

FIG. 8 is the relative fluorescence intensity of Polymer P5 as a function of Fe³⁺Linear dependence of concentration change.

FIG. 9 is a graph comparing the relative fluorescence intensity of the polymer P1 in different cationic systems.

FIG. 10 is a graph comparing the relative fluorescence intensity of the polymer P2 in different cationic systems.

FIG. 11 is a graph comparing the relative fluorescence intensity of the polymer P3 in different cationic systems.

FIG. 12 is a graph comparing the relative fluorescence intensity of polymer P5 in different cationic systems.

Detailed Description

The invention will be further described in detail with reference to the following figures and examples, but the scope of the invention is not limited to these examples.

Example 1

0.2g (6.71 × 10)^-4mol)2,2 '-diamino-6, 6' -bibenzobisthiazole, 0.099g (7.381 × 10)^- ⁴mol)1, 4-terephthalaldehyde, 0.0256g (1.34 × 10)^-4mol)CuI、0.206g(1.41×10^-3mol) anhydrous K₂CO₃Adding into a dry three-neck flask, vacuumizing and filling with argon, circulating three times, and adding 0.263g (1.41 × 10)^-3mol) 1-ethynyl-4-hexylbenzene is dissolved in 6.7m L anhydrous DMSO, the obtained solution is added into the three-neck flask by a syringe, the three-neck flask is heated to 80 ℃, stirred and reacted for 72h, after the reaction is finished, the temperature is cooled to room temperature, 100m L dichloromethane is added into the reaction solution, then the reaction solution is respectively washed for 3 times by 50m L saturated saline solution and 50m L saturated ammonium chloride aqueous solution, anhydrous magnesium sulfate is added into the organic layer for drying overnight, reduced pressure distillation is carried out to obtain a crude product, the obtained crude product is dissolved in tetrahydrofuran and dialyzed for 2 days, and finally, a yellow brown powder fused heterocyclic conjugated polymer P1 is obtained with the yield of 54.3 percent, and the structural characterization result is as follows:

¹H NMR(400MHz,CDCl₃)(ppm)8.10-7.25(22H,ArH),4.29(s,4H,CH₂),2.69-2.65(m,8H,CH₂),1.58-1.55(m,8H,CH₂),1.32-1.24(m,8H,CH₂),0.96-0.87(t,6H,CH₃)；FT-IR(KBr)3031,2923,2852,2729,1604,1465,1207,1122,1014,817。

the polymer had Mn of 5.7 × 10 as determined by gel permeation chromatography⁴，Mw＝9.1×10⁴，Mw/Mn＝1.59。

Example 2

In this example, 1, 4-terephthalaldehyde in example 1 was replaced with equimolar 2, 5-thiophenedicarboxaldehyde, and the other steps were the same as in example 1, to finally obtain a tan solid fused heterocyclic conjugated polymer P2 in 58.9% yield, which was characterized by the following structure:

¹H NMR(400MHz,CDCl₃)(ppm)8.03-7.06(18H,ArH),4.62(s,4H,CH₂),2.63-2.55(m,8H,CH₂),1.55-1.51(m,8H,CH₂),1.23-1.19(m,8H,CH₂),0.81-0.77(t,6H,CH₃)；FT-IR(KBr)2930,2862,2725,1701,1606,1465,1261,1099,1018,833。

the polymer had Mn of 6.8 × 10 as determined by gel permeation chromatography⁴，Mw＝12.4×10⁴，Mw/Mn＝1.81。

Example 3

In this example, 1-ethynyl-4-hexylbenzene in example 1 was replaced by equimolar ethyl propiolate, and after the reaction was completed, the reaction solution was poured into 100m L cold water, allowed to stand for 30min, and filtered to obtain a crude product, and the other steps were the same as in example 1, to finally obtain a yellow solid fused heterocyclic conjugated polymer P3 in a yield of 45.5%, and the structural characterization results were as follows:

¹H NMR(400MHz,CDCl₃)(ppm)8.13-7.29(14H,ArH),4.32(s,4H,CH₂),4.13-4.09(m,4H,CH₂),1.22-1.18(t,6H,CH₃)；FT-IR(KBr)2985,2902,2827,2735,1720,1607,1271,1219,1166,1039,985,825。

the polymer has Mn of 1.9 × 10 by gel permeation chromatography test⁴，Mw＝3.7×10⁴，Mw/Mn＝1.88。

Example 4

In this example, 1, 4-terephthalaldehyde in example 3 was replaced by equimolar 2, 5-thiophenedicarboxaldehyde, and the other steps were the same as in example 3, to finally obtain a yellow solid fused heterocyclic conjugated polymer P4 in 47.3% yield, which was structurally characterized as follows:

¹H NMR(400MHz,CDCl₃)(ppm)8.41-7.30(10H,ArH),4.32(s,4H,CH₂),4.23-4.18(m,4H,CH₂),1.22-1.88(t,6H,CH₃)；FT-IR(KBr)2979,2933,2862,1722,1637,1537,1444,1373,1205,1026,810。

the polymer has Mn of 1.8 × 10 by gel permeation chromatography test⁴，Mw＝3.3×10⁴，Mw/Mn＝1.78。

Example 5

In this example, the ethyl propiolate in example 3 was replaced by equimolar phenylpropargyl acetylene acid, and the other steps were the same as in example 3, to obtain a yellow solid fused heterocyclic conjugated polymer P5 with a yield of 44.9%, and the structural characterization results were as follows:

¹H NMR(400MHz,CDCl₃)(ppm)7.91-7.22(24H,ArH),4.02(s,4H,CH₂)；FT-IR(KBr)3080,2920,1701,1625,1446,1299,1186,1107,1107,817。

the polymer has Mn of 0.8 × 10 by gel permeation chromatography test⁴，Mw＝1.7×10⁴，Mw/Mn＝2.01。

Example 6

In this example, 1, 4-terephthalaldehyde in example 5 was replaced by equimolar 2, 5-thiophenedicarboxaldehyde, and the other steps were the same as in example 5, to finally obtain a yellow solid fused heterocyclic conjugated polymer P6 in 47.7% yield, which was structurally characterized as follows:

¹H NMR(400MHz,CDCl₃)(ppm)8.02-7.18(20H,ArH),4.12(s,4H,CH₂)；FT-IR(KBr)2962,2921,2852,1718,1604,1244,1174,1107,1020,833。

the polymer has Mn of 1.1 × 10 as determined by gel permeation chromatography⁴，Mw＝2.1×10⁴，Mw/Mn＝1.89。

Example 7

Fused heterocyclic conjugated Polymer P prepared in example 11 in the detection of Fe³⁺The specific method comprises the following steps:

the fused heterocyclic conjugated polymer P1 is dissolved in tetrahydrofuran to be prepared into 1.0 × 10^-6A tetrahydrofuran solution of L P1 mol/mol, 3m L10^-6Adding a tetrahydrofuran solution of L P1 mol/mol into a cuvette, and adding Fe into the cuvette³⁺Standard samples, respectively adding Fe to the obtained mixed solution³⁺Is 0, 3.33, 6.67, 10, 13.3, 16.67 and 20 mu mol/L, and different concentrations of Fe are measured by a fluorescence spectrometer³⁺Fluorescence spectra of the corresponding systems (see FIG. 1) and plotted for different concentrations of Fe at 440nm³⁺Relative fluorescence intensity of the corresponding system with Fe³⁺Standard curve of concentration change.

As can be seen from FIG. 1, the fluorescence intensity of P1 is affected by Fe³⁺The effect of the concentration changes clearly, accompanied by Fe³⁺The fluorescence intensity of the system gradually decreases with increasing concentration. As can be seen from FIG. 2, Fe³⁺When the concentration of (b) is 0-20 [ mu ] mol/L, the relative fluorescence intensity is dependent on Fe³⁺The concentration increases linearly, the linear equation is:

y＝0.3604x₁+1

wherein y is the relative fluorescence intensity, x₁Is Fe³⁺Concentration, coefficient of correlation R²Is 0.9861. From this, the relative fluorescence intensity and Fe were observed³⁺The linear relationship of the concentrations is good. Calculating the lowest detection limit by using the formula of the lowest detection limit, P1 for Fe³⁺Has high detection sensitivity with detection limit of 9.483 × 10^-6mol/L。

Example 8

Detection of Fe in fused heterocyclic conjugated Polymer (P2) prepared in example 2³⁺The specific method is the same as in example 7. As can be seen from FIG. 3, the fluorescence intensity of P2 is affected by Fe³⁺The effect of the concentration changes clearly, accompanied by Fe³⁺The fluorescence intensity of the system gradually decreases with increasing concentration. As can be seen from FIG. 4, Fe³⁺When the concentration of (b) is 0-20 [ mu ] mol/L, the relative fluorescence intensity is dependent on Fe³⁺The concentration increases linearly, the linear equation is:

y＝0.3259x₂+1

wherein y is the relative fluorescence intensity, x₂Is Fe³⁺Concentration, coefficient of correlation R²Is 0.9914. From this, the relative fluorescence intensity and Fe were observed³⁺The linear relationship of the concentrations is good. Calculating the lowest detection limit by using the formula of the lowest detection limit, P2 for Fe³⁺Has high detection sensitivity with detection limit of 5.860 × 10^-6mol/L。

Example 9

Fused-heterocycle conjugated polymer P3 prepared in example 3 for detecting Fe³⁺The specific method is the same as in example 7. As can be seen from FIG. 5, the fluorescence intensity of P3 is affected by Fe³⁺The effect of the concentration changes clearly, accompanied by Fe³⁺The fluorescence intensity of the system gradually decreases with increasing concentration. As can be seen from FIG. 6, Fe³⁺When the concentration of (b) is 0-20 [ mu ] mol/L, the relative fluorescence intensity is dependent on Fe³⁺The concentration increases linearly, the linear equation is:

y＝0.3499x₃+1

wherein y is the relative fluorescence intensity, x₃Is Fe³⁺Concentration, coefficient of correlation R²Is 0.9633. From this, the relative fluorescence intensity and Fe were observed³⁺The linear relationship of the concentrations is good. Calculating the lowest detection limit by using the formula of the lowest detection limit, P3 for Fe³⁺Has high detection sensitivity with detection limit of 8.377 × 10^-6mol/L。

Example 10

Fused-heterocycle conjugated polymer P5 prepared in example 5 for detecting Fe³⁺The specific method is the same as in example 7. As can be seen from FIG. 7, the fluorescence intensity of P1 is affected by Fe³⁺The effect of the concentration changes clearly, accompanied by Fe³⁺The fluorescence intensity of the system gradually decreases with increasing concentration. As can be seen from FIG. 8, Fe³⁺When the concentration of (b) is 0-20 [ mu ] mol/L, the relative fluorescence intensity is dependent on Fe³⁺The concentration increases linearly, the linear equation is:

y＝0.2119x₄+1

wherein y is the relative fluorescence intensity, x₄Is Fe³⁺Concentration, coefficient of correlation R²Is 0.9676. From this, the relative fluorescence intensity and Fe were observed³⁺The linear relationship of the concentrations is good. Calculating the minimum detection by using the formula of the minimum detection limitOut limit, P5 vs Fe³⁺Has high detection sensitivity and detection limit of 1.18 × 10^-6mol/L。

To prove the fused heterocyclic conjugated polymer of the present invention is p-Fe³⁺The inventors employed the fused heterocyclic conjugated polymers of examples 1, 2, 3, and 5, respectively, for Ag⁺、Ba²⁺、Ca²⁺、Cd²⁺、Cu²⁺、Mg²⁺、Mn²⁺、Ni²⁺、Pd²⁺、Zn²⁺、Hg²⁺、Al³⁺And Fe³⁺These 13 heavy metal cations (with a polymer concentration of 1.0 × 10)^-6mol/L, prepared by taking tetrahydrofuran as solvent, and the concentration of metal ions in the detection system is 1.0 × 10^-4mol/L) and the results are shown in figures 9-12, it can be seen from the figures that when Fe is added³⁺In the process, the fluorescence quenching effect of the detection system is strongest, and other ions almost have no fluorescence quenching effect, so that the fused heterocyclic conjugated polymer can be used for detecting Fe with high selectivity³⁺。

Claims

1. For detecting Fe³⁺The fused heterocyclic conjugated polymer is characterized in that the structural unit of the polymer is shown as follows:

in the formula R₁Represents

2. The process for producing a fused heterocyclic conjugated polymer according to claim 1, wherein: adding a bisazine monomer shown as a formula I, a monomer shown as a formula II and containing two aldehyde groups, an alkyne monomer shown as a formula III, copper salt and alkali into dimethyl sulfoxide, carrying out polymerization reaction under the protection of inert gas and stirring at 70-90 ℃, and extracting, drying and dialyzing after the reaction is finished to obtain a fused heterocyclic conjugated polymer;

in the formula III, R₃Represents hydrogen or carboxyl.

3. The method for producing a fused heterocyclic conjugated polymer according to claim 2, wherein: the copper salt is any one of cuprous chloride, cuprous iodide and cuprous bromide.

4. The method for producing a fused heterocyclic conjugated polymer according to claim 2, wherein: the alkali is any one of anhydrous potassium carbonate and anhydrous sodium carbonate.

5. The method for producing a fused heterocyclic conjugated polymer according to any one of claims 2 to 4, wherein: the molar ratio of the bisazine monomer to the monomer containing two aldehyde groups to the alkyne monomer is 1: 1.0-3.0: 2.0-5.0.

6. The method for producing a fused heterocyclic conjugated polymer according to any one of claims 2 to 4, wherein: the molar ratio of the bisazine monomer to the copper salt to the alkali is 1: 0.02-0.5: 2.0-5.0.

7. The fused heterocyclic conjugated polymer of claim 1 for detecting Fe³⁺The use of (1).