CN113773491A

CN113773491A - Polybenzimidazole derivative and application thereof in field of fluorescent probes

Info

Publication number: CN113773491A
Application number: CN202110917008.4A
Authority: CN
Inventors: 汪朝阳; 曹西颖; 罗时荷; 庞楚明
Original assignee: South China Normal University
Current assignee: South China Normal University
Priority date: 2021-08-11
Filing date: 2021-08-11
Publication date: 2021-12-10
Anticipated expiration: 2041-08-11
Also published as: CN113773491B

Abstract

The invention discloses a polybenzimidazole derivative and application thereof in the field of fluorescent probes. The invention takes trans-butenedioic acid as a bridge to synthesize novel conjugated polybenzimidazole with a large conjugated nano microsphere structure, and modifies insoluble conjugated polybenzimidazole through N-alkylation reaction, thereby successfully obtaining the nano microsphere polybenzimidazole derivative with good solubility and optical performance. The polymer has adjustable fluorescence, and can be used as a multifunctional fluorescent probe for simultaneously detecting Cu²⁺And Zn²⁺Can also be used as a turn-off type fluorescent probeThe method realizes the simultaneous detection of various metal ions, and the polymer has lower detection limit. In addition, the modified polymer can be used for manufacturing and detecting Cu²⁺The test paper and the thin-layer chromatographic plate realize rapid detection, and the modified polymer can also be designed into an implication door with ultra-sensitive molecular level.

Description

Polybenzimidazole derivative and application thereof in field of fluorescent probes

Technical Field

The invention belongs to the field of organic chemistry, and particularly relates to a polybenzimidazole derivative and application thereof in the field of fluorescent probes.

Background

In the field of conjugated polymer probes, organic backbone conjugated polymer probes are composed of unsaturated structural units (such as aromatic hydrocarbons, olefins or acetylene) and are easy to form large electron delocalization, i.e., polarizable pi-electron domains, so that the probes have excellent optical and electrical properties and are receiving much attention. The fluorescent conjugated polymer is used as a molecular guide line, namely, a point contact and multipoint response, electrons can flow along the whole conjugated chain, so that an amplified fluorescent signal is generated, and the capability of detecting ultralow-content analytes is determined. Therefore, the synthesis and application of organic conjugated macromolecular chemical sensors are receiving more and more attention.

The preparation of the reported conjugated polymer fluorescent material and the regulation and control of the conjugated polymer fluorescent material on fluorescence mainly constitute the following fluorescent probes: the method comprises the steps of regulating and controlling fluorescence based on changing the length of an alkyl chain in a side chain, modifying active NH in a conjugated polymer side chain, carrying out quaternization modification on N atoms in the polymer side chain by halogenated hydrocarbon, directly introducing a new luminophore into the polymer side chain and the like. At present, methods for synthesizing a conjugated polymer and modifying the conjugated polymer to be used as a probe are various, but most of the polymers are very complex in preparation method and high in production cost, even transition metal catalysis and the like are involved, and quantitative production is difficult to realize. Therefore, there is a need to develop a conjugated polymer that is easy to synthesize and can be used as a probe.

Disclosure of Invention

In order to overcome the above problems of the prior art, it is an object of the present invention to provide a polybenzimidazole derivative; the second object of the present invention is to provide a process for producing the polybenzimidazole derivative; the invention also aims to provide the application of the polybenzimidazole derivative in the field of fluorescent probes; the fourth purpose of the invention is to provide an entailment door; the fifth purpose of the invention is to provide a test paper; the sixth object of the present invention is to provide a thin layer chromatography plate.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

the invention provides a polybenzimidazole derivative, which contains a repeating unit shown as a formula (I):

in the formula (I), R¹、R²Are independently selected from hydrogen, substituted or unsubstituted alkyl; r³、R⁴、R⁵Are independently selected from substituted or unsubstituted alkyl; x is a natural number; y is a positive integer.

Preferably, in the polybenzimidazole derivative represented by the formula (I), R is¹、R²Each independently selected from hydrogen or n-pentyl; r³、R⁴、R⁵Is n-pentyl.

Preferably, in the polybenzimidazole derivative represented by formula (i), the terminal group comprises a structure represented by formula (ii) or formula (iii):

preferably, in the polybenzimidazole derivative shown in the formula (I), x is more than or equal to 0 and less than or equal to 30, and y is more than or equal to 1 and less than or equal to 30; more preferably, in the polybenzimidazole derivative represented by formula (I), x is 0. ltoreq. x.ltoreq.25, and y is 1. ltoreq. y.ltoreq.25.

Preferably, in the polybenzimidazole derivative shown by the formula (I), x is more than or equal to 3 and y is less than or equal to 30; more preferably, in the polybenzimidazole derivative represented by the formula (I), x is more than or equal to 3 and y is less than or equal to 25.

Preferably, the polybenzimidazole derivative comprises the following structure:

in the

above formulae

1,2, 3, 4 and 5, x and y are positive integers, respectively.

Preferably, the number average molecular weight of the polybenzimidazole derivative is 2500g/mol to 5500 g/mol; more preferably, the number average molecular weight of the polybenzimidazole derivative is 2700g/mol to 5000 g/mol; still more preferably, the polybenzimidazole derivative has a number average molecular weight of 2900g/mol to 4300 g/mol.

A second aspect of the present invention provides a method for preparing a polybenzimidazole derivative according to the first aspect of the present invention, comprising the steps of:

mixing 3,3 ', 4, 4' -tetraaminobenzidine and fumaric acid, and reacting to obtain the polybenzimidazole derivative.

Preferably, the molar ratio of the 3,3 ', 4, 4' -tetraaminobenzidine to the fumaric acid is 1 (0.6-1.5); further preferably, the molar ratio of the 3,3 ', 4, 4' -tetraaminobenzidine to the fumaric acid is 1 (0.8-1.3); still more preferably, the molar ratio of the 3,3 ', 4, 4' -tetraaminobenzidine to fumaric acid is 1 (0.9-1.1).

Preferably, the reaction temperature is 140-200 ℃; further preferably, the reaction temperature is 150-190 ℃; still further preferably, the reaction temperature is 160 ℃ to 180 ℃.

Preferably, the reaction time is 36-60 h; further preferably, the reaction time is 42h-54 h; still more preferably, the reaction time is 45h to 51 h.

Preferably, the method for preparing the polybenzimidazole derivative further comprises the step of alkylating the polybenzimidazole derivative.

Preferably, the alkylation of the polybenzimidazole derivative comprises the following steps:

mixing the obtained polybenzimidazole derivative with halogenated alkane, and reacting to obtain the alkylated polybenzimidazole derivative.

Preferably, the halogenated alkane is brominated alkane; further preferably, the halogenated alkane is 1-bromo-n-pentane.

Preferably, the molar ratio of the polybenzimidazole derivative repeating structural unit to the halogenated alkane is 1 (0.5-6); further preferably, the molar ratio of the polybenzimidazole derivative repeating structural unit to the halogenated alkane is 1 (0.8-5); still more preferably, the molar ratio of the repeating structural unit of the polybenzimidazole derivative to the halogenated alkane is 1 (1-4).

Preferably, the reaction temperature is 70-120 ℃; further preferably, the reaction temperature is 80-110 ℃; still further preferably, the reaction temperature is 90 ℃ to 100 ℃.

Preferably, the reaction time is 16h-32 h; further preferably, the reaction time is 18h-30 h; still more preferably, the reaction time is 20h to 28 h.

The third aspect of the present invention provides the use of the polybenzimidazole derivative provided by the first aspect of the present invention in the field of fluorescent probes.

Preferably, the fluorescent probe is used for detecting copper ions and zinc ions.

Preferably, the detection method comprises the following steps:

testing the fluorescence emission spectrum of the polybenzimidazole derivative by using a fluorescence spectrometer;

mixing the polybenzimidazole derivative with copper ions or zinc ions;

the fluorescence emission spectrum of the mixed solution was measured by a fluorescence spectrometer.

In a fourth aspect, the present invention provides an IMPLICATION gate (IMPLICATION logic gate) comprising a polybenzimidazole derivative according to the first aspect of the present invention.

In a fifth aspect, the present invention provides a test strip comprising a polybenzimidazole derivative according to the first aspect of the present invention.

Preferably, the test paper is used for detecting copper ions and zinc ions.

A sixth aspect of the present invention provides a thin layer chromatography plate comprising a polybenzimidazole derivative provided according to the first aspect of the present invention.

Preferably, the thin layer chromatography plate is used for detecting copper ions and zinc ions.

The invention has the beneficial effects that:

the invention takes trans-butenedioic acid (E-BA) as a bridge to synthesize novel Conjugated Polybenzimidazole (CPBI) with a large Conjugated nano microsphere structure, and modifies insoluble Conjugated polybenzimidazole through N-alkylation reaction, thereby successfully obtaining the nano microsphere polybenzimidazole derivative with good solubility and optical performance. The polymer has adjustable fluorescence, and can be used as a multifunctional fluorescent probe for simultaneously detecting Cu²⁺And Zn²⁺The fluorescent probe can also be used as a 'turn-off' type fluorescent probe to realize the simultaneous detection of a plurality of metal ions, and the polymer has lower detection limit. In addition, the modified polymer can be used for manufacturing and detecting Cu²⁺The test paper and the thin-layer chromatographic plate realize rapid detection, and the modified polymer can also be designed into an implication door with ultra-sensitive molecular level.

Specifically, the invention has the following advantages:

(1) the invention obtains the polybenzimidazole derivative with large conjugated series by polymerizing the fumaric acid and the 3,3 ', 4, 4' -tetraaminobenzidine and then carrying out N-alkylation reaction. According to the invention, the form of the alkyl modified conjugated polymer can be adjusted by controlling the feeding ratio of the conjugated polybenzimidazole to the halogenated alkane, and finally the formation of nano/microspheres can be observed. The invention adopts FT-IR,¹And carrying out structural characterization by using analytical test methods such as H NMR and SEM, and confirming the microscopic morphology of the polymer.

(2) The preparation method provided by the invention is simple and efficient, green and pollution-free, and the conjugated polybenzimidazole derivative is obtained through nonmetal catalysis.

(3) The polybenzimidazole derivative provided by the invention can be used as a 'turn-off' type fluorescent probe of an intrinsic door, and can realize the effect of Cu²⁺And Zn²⁺Detecting; the modified polymer can be used for preparing and detecting Cu²⁺The test paper and the thin-layer chromatographic plate realize rapid detection, and the modified polymer can also be designed into an implication door with ultra-sensitive molecular level, and provides a new idea for the simple synthesis of multifunctional materials.

Drawings

FIG. 1 is a chemical reaction scheme for preparing conjugated polybenzimidazole according to the present invention.

FIG. 2 is a chemical reaction diagram of the present invention for preparing alkylated modified conjugated polybenzimidazole.

FIG. 3 is a diagram of a conjugated polybenzimidazole CPBI₀Infrared spectrum test chart.

FIG. 4 is a diagram of a conjugated polybenzimidazole CPBI₁Infrared spectrum test chart.

FIG. 5 is a diagram of a conjugated polybenzimidazole CPBI₂Infrared spectrum test chart.

FIG. 6 is a CPBI of conjugated polybenzimidazole₃Infrared spectrum test chart.

FIG. 7 is a diagram of a conjugated polybenzimidazole CPBI₄Infrared spectrum test chart.

FIG. 8 is a diagram of a conjugated polybenzimidazole CPBI₀Nuclear magnetic resonance hydrogen spectrum of (a).

FIG. 9 is a CPBI of conjugated polybenzimidazole₁Nuclear magnetic resonance hydrogen spectrum of (a).

FIG. 10 is a CPBI of conjugated polybenzimidazole₂Nuclear magnetic resonance hydrogen spectrum of (a).

FIG. 11 is a CPBI of conjugated polybenzimidazole₃Nuclear magnetic resonance hydrogen spectrum of (a).

FIG. 12 is a CPBI of conjugated polybenzimidazole₄Nuclear magnetic resonance hydrogen spectrum of (a).

FIG. 13 is a CPBI of conjugated polybenzimidazole₀Scanning the surface electron microscope of (2).

FIG. 14 is a diagram of a conjugated polybenzimidazole CPBI₁Scanning the surface electron microscope of (2).

FIG. 15 is a diagram of conjugated polybenzimidazole CPBI₂Scanning the surface electron microscope of (2).

FIG. 16 is a diagram of conjugated polybenzimidazole CPBI₃Scanning the surface electron microscope of (2).

FIG. 17 is a CPBI of conjugated polybenzimidazole₄Surface electron microscope scan of。

FIG. 18 is a fluorescence absorption spectrum of conjugated polybenzimidazole.

FIG. 19 shows CPBI₂Interaction with copper and zinc ions.

FIG. 20 shows CPBI₂And (4) an infrared spectrum and a surface electron microscope scanning analysis chart after interaction with copper and zinc ions.

FIG. 21 shows CPBI₂And Cu²⁺And a cycle titration plot of EDTA.

FIG. 22 shows CPBI₂And Cu²⁺A fluorescent detection plate and a test strip sample of (1).

Detailed Description

The following description of the embodiments of the present invention is provided in connection with the accompanying drawings and examples, but the invention is not limited thereto. It is noted that the processes described below, if not specifically described in detail, are all realizable or understandable by those skilled in the art with reference to the prior art. The reagents or apparatus used are not indicated to the manufacturer, and are considered to be conventional products available through commercial purchase.

FIG. 1 is a chemical reaction scheme for preparing conjugated polybenzimidazole according to the present invention. The invention will be further described with reference to specific embodiments in the following, with reference to fig. 1.

Example 1

The polymer of this example, a conjugated polybenzimidazole CPBI₀The preparation steps are as follows:

20mL of polyphosphoric acid (PPA) was added to a three-necked flask, and stirred at 160 ℃ for 1.5 hours, then 3.0mmol of 3, 3' -diaminobenzidine 1 was weighed and slowly added to the three-necked flask, and after it was completely dissolved, 3.0mmol of trans-butenedioic acid (E-BA) was added, and the temperature was raised to 170 ℃ to react for 48 hours. Stopping the reaction, cooling to room temperature, adjusting the pH value to be alkaline by using a NaOH solution, and performing suction filtration to obtain a solid crude product. Then, the crude product is washed with hot water, ethyl acetate, petroleum ether and other solvents for several times to remove unreacted raw materials and some products with lower molecular weight. Finally, the mixture is dried in a vacuum drying oven at 50 ℃ for 24 hours to obtain a product which is marked as CPBI₀。

Due to the prepared conjugated polybenzimidazole CPBI₀Solution of (2)Poor resolvability and difficult related research, and the invention is realized by carrying out the CPBI₀The alkylation modification is carried out to increase the solubility of the conjugated polybenzimidazole. FIG. 2 is a chemical reaction diagram of the present invention for preparing alkylated modified conjugated polybenzimidazole. The present invention will be further described with reference to specific embodiments in the following, with reference to fig. 2.

Example 2

The polymer of this example, a conjugated polybenzimidazole CPBI₁The preparation steps are as follows:

258.3mg (1mmol) of intermediate CPBI are weighed₀And 0.08g (2mmol) of NaOH solid in a round-bottom flask, then adding 10mL of acetonitrile as a solvent, refluxing at 95 ℃ for 1.5h, then dropwise adding 151mg (1mmol) of 1-bromopentane, refluxing for 24h, stopping the reaction, and distilling off the solvent under reduced pressure. Washing with water for multiple times to remove NaOH in the product, alternately leaching the alkylated product with dichloromethane and ethanol, collecting the organic phase, spin-drying, drying in a vacuum drying oven at 40 deg.C for 24 hr to obtain alkylated product, and recording as CPBI₁。

Example 3

The polymer of this example, a conjugated polybenzimidazole CPBI₂The preparation steps are as follows:

this example differs from example 2 in that the mass of 1-bromopentane added dropwise is 302mg (2mmol), the other starting materials and procedures are identical to those of example 2, and the product obtained is designated as CPBI₂。

Example 4

The polymer of this example, a conjugated polybenzimidazole CPBI₃The preparation steps are as follows:

this example differs from example 2 in that the mass of 1-bromopentane added dropwise is 453mg (3mmol), the other starting materials and procedures are identical to those of example 2, and the product obtained is denoted as CPBI₃。

Example 5

The polymer of this example, a conjugated polybenzimidazole CPBI₄The preparation steps are as follows:

this example differs from example 2 in that the mass of 1-bromopentane added dropwise is 604mg (4mmol), the other starting materials and procedures are identical to those of example 2, and the product obtained is denoted as CPBI₄。

The prepared conjugated polybenzimidazole CPBI₀The solid color is blue black; after the polymer is subjected to alkylation modification, the color of the polymer becomes brown, and gradually becomes lighter along with the increase of the alkylation rate, and CPBI₄The color of the solid of (1) is orange yellow.

Test example 1

The infrared spectroscopy of the conjugated polybenzimidazole and its derivatives prepared in the examples was carried out, and the results were as follows:

the prepared CPBI₀Infrared spectroscopy was performed, and FIG. 3 shows CPBI of conjugated polybenzimidazole₀Infrared spectrum test chart. Test results CPBI As shown in FIG. 3₀FT-IR analysis (KBr, v, cm)^-1): 3389(N-H stretching vibration), 3051 (aromatic ring unsaturated C-H stretching vibration), 1704,1629(C ═ N stretching vibration), 1225,1159(C-N stretching vibration), 973 (trans C ═ C stretching vibration), 895,812 (

benzene ring

1,2, 4-trisubstituted).

The prepared CPBI₁Infrared spectroscopy was performed, and FIG. 4 shows CPBI of conjugated polybenzimidazole₁Infrared spectrum test chart. Test results CPBI As shown in FIG. 4₁FT-IR analysis (KBr, v, cm)^-1): 3382(N-H stretching vibration), 3075 (aromatic ring unsaturated C-H stretching vibration), 2954,2923,2854 (saturated C-H stretching vibration), 1659(C ═ N stretching vibration), 1616,1574 (aromatic ring skeleton vibration), 1466 (saturated C-H bending vibration), 1372,1297(C-N stretching vibration), 964 (trans C ═ C stretching vibration), 860,803 (

benzene ring

1,2, 4-trisubstituted).

The prepared CPBI₂Infrared spectroscopy was performed and FIG. 5 shows the CPBI of the conjugated polybenzimidazole₂Infrared spectrum test chart. Test results As shown in FIG. 5, CPBI₂FT-IR analysis (KBr, v, cm)^-1): 3390(N-H stretching vibration), 3054 (aromatic ring unsaturated C-H stretching vibration), 2955,2927,2853 (saturated C-H stretching vibration), 1654(C ═ N stretching vibration), 1617,1568 (aromatic ring skeleton vibration), 1461 (saturated C-H bending vibration), 1327,1229(C-N stretching vibration), 957 (trans C ═ C stretching vibration), 857,801 (

benzene ring

1,2, 4-trisubstituted), 724 (multiple-CH-linear chain deformation vibration).

The prepared CPBI₃Go to redExternal Spectroscopy assay, FIG. 6 is the conjugated polybenzimidazole CPBI₃Infrared spectrum test chart. Test results CPBI As shown in FIG. 6₃FT-IR analysis (KBr, v, cm)^-1): 3388(N-H stretching vibration), 3051 (aromatic ring unsaturated C-H stretching vibration), 2957,2922,2852 (saturated C-H stretching vibration), 1663(C ═ N stretching vibration), 1621,1570 (aromatic ring skeleton vibration), 1467 (saturated C-H bending vibration), 1369,1318(C-N stretching vibration), 963 (trans C ═ C stretching vibration), 857,795 (

benzene ring

1,2, 4-trisubstituted), 723 (multiple-CH-linear deformation vibration).

The prepared CPBI₄Infrared spectroscopy was performed and FIG. 7 shows the CPBI of conjugated polybenzimidazole₄Infrared spectrum test chart. Test results As shown in FIG. 7, CPBI₄FT-IR analysis (KBr, v, cm)^-1): 3375(N-H stretching vibration), 3052 (aromatic ring unsaturated C-H stretching vibration), 2956,2925,2856 (saturated C-H stretching vibration), 1661(C ═ N stretching vibration), 1615,1571 (aromatic ring skeleton vibration), 1466(C-H bending vibration), 1371,1320(C-N stretching vibration), 961 (trans C ═ C stretching vibration), 850,802 (

benzene ring

1,2, 4-trisubstituted), 724 (multiple-CH-linear chain deformation vibration).

Test example 2

The conjugated polybenzimidazole and the derivative thereof prepared in the example are subjected to a nuclear magnetic resonance hydrogen spectrum test, and the test results are as follows:

will CPBI₀NMR spectroscopy was performed and FIG. 8 shows CPBI of conjugated polybenzimidazole₀Nuclear magnetic resonance hydrogen spectrum of (a). FIG. 8 analysis¹H NMR(DMSO-d₆,600MHz):6.32～6.67(m,H_g,＝CH),6.87～7.08(m,H_e,H_f,＝CH),7.51(d,J＝4.0Hz,H_i,Ar-H),7.54(d,J＝4.0Hz,H_h,Ar-H),7.63(s,H_j,Ar-H),7.81～7.90(m,H_a,H_a',Ar-H),7.96～8.08(m,H_b,H_b',Ar-H),8.18～8.25(m,H_c,H_c',Ar-H),12.51(s,H_k,H_l-COOH and-NH), 13.03(s, H)_d,H_d’,-N-H)；

Will CPBI₁NMR hydrogen spectroscopy was performed and FIG. 9 shows CPBI of conjugated polybenzimidazole₁Nuclear magnetic resonance hydrogen spectrum of (a). FIG. 9 analysis¹H NMR(DMSO-d₆,600MHz):0.86～0.92(m,H_j,-CH₃),1.35～1.62(m,H_i,H_h,-CH₂-),1.78～1.83(m,H_g,-CH₂-),3.51～4.55(m,H_f,-NCH₂),6.57～6.67(s,H_f',＝CH),6.88～7.21(s,H_e,H_e',＝CH),7.56～7.62(m,H_a,H_a',Ar-H),7.68～7.72(m,H_b,H_b',Ar-H),7.82～7.89(m,H_c,H_c',Ar-H),8.10(d,J＝8.0Hz,H_j',Ar-H),8.16(d,J＝8.0Hz,H_i',Ar-H),8.23(s,H_k',Ar-H),12.69(s,H_g’,-NH)；

Will CPBI₂NMR hydrogen spectroscopy was performed and FIG. 10 shows CPBI of conjugated polybenzimidazole₂Nuclear magnetic resonance hydrogen spectrum of (a). FIG. 10 analysis¹H NMR(DMSO-d₆,600MHz):0.86～0.91(m,H_j,-CH₃),1.32～1.51(m,H_h,H_i,-CH₂-),1.78～1.84(m,H_g,-CH₂-),4.23～4.51(m,H_f,-NCH₂-),6.63(m,H_f',＝CH),6.85～7.19(s,H_e,H_e',＝CH),7.56～7.62(m,H_a,H_a',Ar-H),7.67～7.72(m,H_b,H_b',Ar-H),7.88～7.99(m,H_c,H_c',Ar-H),8.10(d,J＝8.0Hz,H_j',Ar-H),8.16(d,J＝8.0Hz,H_i',Ar-H),8.22(s,H_k',Ar-H),12.81(s,H_d,-NH)；

Will CPBI₃NMR spectroscopy was performed and FIG. 11 shows conjugationPolybenzimidazole CPBI₃Nuclear magnetic resonance hydrogen spectrum of (a). FIG. 11 analysis¹H NMR(DMSO-d₆,600MHz):0.85～0.87(m,H_j,-CH₃),1.27～1.51(m,H_h,H_i,-CH₂-),1.74～1.90(m,H_g,-CH₂-),4.04～4.50(m,H_f,-NCH₂-),6.59～6.67(m,H_f',＝CH),6.87～7.26(s,H_e,H_e',＝CH),7.58～7.62(m,H_a,H_a',Ar-H),7.72～7.77(m,H_b,H_b',Ar-H),7.96～8.05(m,H_c,H_c',Ar-H),8.10(d,J＝8.0Hz,H_j',Ar-H),8.17(d,J＝8.0Hz,H_i',Ar-H),8.24(s,H_k',Ar-H),13.16(s,H_d,-NH)；

Will CPBI₄NMR hydrogen spectroscopy was performed and FIG. 12 shows CPBI of conjugated polybenzimidazole₄Nuclear magnetic resonance hydrogen spectrum of (a). FIG. 12 analysis¹H NMR(DMSO-d₆,600MHz):0.86～0.88(m,H_j,-CH₃),1.36～1.63(m,H_h,H_i,-CH₂-),1.75～1.87(m,H_g,-CH₂-),4.20～4.51(m,H_f,-NCH₂-),6.63(m,H_f',＝CH),6.86～7.20(s,H_e,H_e',＝CH),7.56～7.61(m,H_a,H_a',Ar-H),7.73～7.80(m,H_b,H_b',Ar-H),7.89～7.99(m,H_c,H_c',Ar-H),8.06(d,J＝8.0Hz,H_j',Ar-H),8.11(d,J＝8.0Hz,H_i',Ar-H),8.18(s,H_k',Ar-H)；

Through nuclear magnetic data calculation, the CPBI prepared in the above way is obtained₁Has a number average molecular weight of 2900g/mol, CPBI₂Has a number average molecular weight of 3500g/mol and CPBI₃Has a number average molecular weight of 3700g/mol and CPBI₄The number average molecular weight of (2) is 4300 g/mol.

Test example 3

The polybenzimidazole and its derivatives prepared in the examples were subjected to surface electron microscope Scanning (SEM) tests, and the results were as follows:

FIG. 13 is a CPBI of conjugated polybenzimidazole₀Scanning the surface electron microscope of (2). FIG. 14 is a diagram of a conjugated polybenzimidazole CPBI₁Scanning the surface electron microscope of (2). FIG. 15 is a diagram of conjugated polybenzimidazole CPBI₂Scanning the surface electron microscope of (2). FIG. 16 is a diagram of conjugated polybenzimidazole CPBI₃Scanning the surface electron microscope of (2). FIG. 17 is a CPBI of conjugated polybenzimidazole₄Scanning the surface electron microscope of (2). As can be seen from FIGS. 13-17, CPBI₀Because of no alkyl side chain, the polymer structure is stacked more closely, and the morphology is a flat sheet structure. From CPBI₁To CPBI₄The morphology of the polymer is known to be gradually transited to the nano microsphere as the original flat sheet structure is destroyed along with the gradual increase of the alkyl side chain.

Test example 4

The polybenzimidazole and its derivatives prepared in the examples have the best solubility in DMSO, so the fluorescence test is carried out in the test examples by using DMSO as a solvent. The polybenzimidazole and the derivative thereof prepared in the example are subjected to fluorescence property test, and the test steps and the test results are as follows:

10mg of sample is dissolved in 2mL of DMSO solvent to prepare stock solution, 200 mu L of the stock solution is diluted to 15mL to obtain the solution to be detected with the mass concentration of 1mg/15mL, and 19 parts of the solution to be detected which is the same as the mass concentration of the solution to be detected is prepared. The solution to be tested is mixed with 10 mul of different metal ion solutions respectively, and the concentration of the metal ions is 0.02 mol/L. And analyzing the fluorescence response behavior of the alkyl modified polybenzimidazole derivative to metal ions by using fluorescence emission spectroscopy. FIG. 18 is a fluorescence absorption spectrum of conjugated polybenzimidazole. Wherein FIG. 18(a) is a polybenzimidazole CPBI₁FIG. 18(b) is a polybenzimidazole CPBI₂FIG. 18(c) is a polybenzimidazole CPBI₃FIG. 18(d) is a polybenzimidazole CPBI₄The fluorescence absorption spectrum of (2). From FIG. 18(a) to FIG. 18(d)Therefore, the alkyl modified polybenzimidazole derivative can interact with copper ions and zinc ions to cause the reduction of the fluorescence intensity of the polymer, and the copper ions and the zinc ions can be detected by utilizing the principle. FIG. 19 shows CPBI₂Interaction with copper and zinc ions. As can be seen from fig. 19, the color of the solution is different after the alkyl-modified polybenzimidazole derivative interacts with copper ions and zinc ions. By CPBI₂For example, CPBI can be seen under a 365nm UV lamp₂The solution after the action with zinc ions changes from original green to yellow; and CPBI₂The reaction with copper ions is only pure fluorescence quenching and has no color change. Therefore, the material obtained by utilizing the principle can realize the simultaneous detection of copper ions and zinc ions.

Will CPBI₂Infrared spectroscopy and Surface Electron Microscopy (SEM) tests were performed after interaction with copper and zinc ions, respectively, and FIG. 20 is CPBI₂And (4) an infrared spectrum and a surface electron microscope scanning analysis chart after interaction with copper and zinc ions. By aiming at CPBI₂The analysis of the infrared spectrum before and after the action with copper and zinc ions and the change of the surface micro-morphology of SEM shows that when CPBI (coherent population interference rejection) is carried out₂And Cu²⁺And Zn²⁺After action, CPBI₂C-N stretch shock absorption (1654 cm)^-1) C-N stretching vibration absorption (1327 cm)^-1) And the strength of the stretching vibration peak of N-H on the imidazole ring are changed to different degrees, and Cu²⁺And Zn²⁺After the action with the probe, the length of the probe is 1121cm^-1And 3540cm^-1A new absorption peak appears. This shows that Cu²⁺And Zn²⁺Can be compared with CPBI₂C ═ N on the imidazole ring in the backbone interacts with un-alkylated C — N.

Application example 1

Due to CPBI₂For Cu²⁺Has the strongest response effect and the most obvious phenomenon, and is applied to CPBI₂And carrying out metal ion cycle detection and visual detection application research. 10 μ L of a copper sulfate solution with a concentration of 0.02mol/L was added dropwise to 2mL of CPBI with a concentration of 0.067mg/mL₂The mixture was mixed well in DMSO solution, and the fluorescence intensity at a wavelength of 502nm was measured. Then will beAnd (3) adding 10 mu L of EDTA solution with the concentration of 0.02mol/L into the mixed solution in a dropwise manner, and measuring the fluorescence intensity of the solution at the wavelength of 502nm after uniform mixing. This was repeated 5 times, and the measured data are shown in FIG. 21. FIG. 21 shows CPBI₂And Cu²⁺And EDTA cycle titration, wherein FIG. 21(a) is CPBI₂And Cu²⁺And EDTA cycle titration sample, FIG. 21(b) is CPBI₂And Cu²⁺And EDTA cycle titration fluorescence intensity histogram, FIG. 21(c) is CPBI₂And Cu²⁺And a cycle titration fluorescence intensity line graph of EDTA. As can be seen from the fluorescence cycle titration experiment and FIG. 21(b), EDTA can be forcibly deprived of CPBI₂Interacting Cu²⁺Let CPBI₂And Cu²⁺And EDTA has the cycle characteristic of fluorescence quenching-recovery. By utilizing the cycle characteristic with fluorescence quenching-recovery, the method can be used for manufacturing an off/on switch of a fluorescence IMPLICATION gate (Impercation logic gate). FIG. 21(d) is a circuit diagram of a fluorescence IMPLICATION gate (Implementation logic gate) "off/on" switch, and FIG. 21(e) is a logic diagram of a fluorescence IMPLICATION gate "off/on" switch. Fig. 21(d) and 21(e) are an implementation logic gate having two inputs (In 1 and In 2) and one output of the display memory cell. Respectively adding Cu²⁺And EDTA is set to input In 1 and input In 2, whose presence and absence are noted as 1 and 0, respectively. The output signal is the emission intensity at 502nm, with the threshold set at 1500a.u. When the fluorescence intensity is higher than the threshold value, outputting a signal as on (1); when the fluorescence intensity is below the threshold, the output signal is off (0). Based on the basic logic gate, when Cu²⁺And EDTA are both present or absent, the output signal is on (1). When In 1 and In 2 are In the (1, 0) state, the output signal is off (0). When In 1 and In 2 are In the (0, 1) state, the output signal is on (1). Thus, by inputting the signal (Cu)²⁺And EDTA) monitoring the emission intensity value at 502nm of the output signal, an IMPLICATION logic gate can be constructed at the molecular level.

Application example 2

CPBI₂And Cu²⁺The fluorescence quenching characteristic of (A) can be obtained by observing under an ultraviolet lamp of 365nmBy using the characteristic, the copper ion fluorescence detection plate and the test paper can be manufactured. FIG. 22 shows CPBI₂And Cu²⁺The fluorescence detection plate and test strip sample of (1), wherein FIG. 22(a) is a CPBI₂And Cu²⁺FIG. 22(b) is a diagram of a sample of the fluorescence detection plate of (1), CPBI₂And Cu²⁺A sample of the fluorescence test strip of (1).

Cu²⁺The preparation and detection processes of the fluorescent detection plate are as follows:

compound CPBI was added drop wise to both ends of a blank Thin Layer Chromatography (TLC) plate₂Putting the DMSO solution into a vacuum drying oven for drying for 12 hours to obtain a detectable TLC plate; CPBI adsorbed on Thin Layer Chromatography (TLC) plates₂Showing green fluorescence. When Cu is added dropwise²⁺Solution in adsorption of CPBI₂On TLC plate of (5), macroscopic CPBI₂The fluorescence at the center of (a) is rapidly quenched as shown in FIG. 22 (a). Thus, adsorbed with CPBI₂Can be used for detecting Cu²⁺。

Cu²⁺The preparation and detection processes of the fluorescence detection test paper are as follows:

soaking Whatman test paper in CPBI₂In DMSO, and then dried in vacuum to obtain CPBI₂And (4) testing the paper. The test paper showed green fluorescence under 365nm UV lamp, once Cu was dropped on the test paper²⁺The fluorescence of the solution was rapidly quenched, and the result is shown in FIG. 22 (b). Therefore, Cu can be realized not only by solution-coated thin layer chromatography but also by a dipstick method²⁺Solid state visual detection of (1).

As can be seen from the above test examples and application examples, CPBI₂Can be used as a circulating detection probe, shows good stability and reversibility, and can also be designed into a chemical sensor of a molecular logic gate. And CPBI₂Can be made into TLC plate or detection test paper to realize visual detection.

The above examples are preferred embodiments of the present invention, but the present invention is not limited to the above examples, and any other changes, modifications, substitutions, combinations, and simplifications which do not depart from the spirit and principle of the present invention should be construed as equivalents thereof, and they are included in the scope of the present invention.

Claims

1. A polybenzimidazole derivative characterized by: the polybenzimidazole derivative contains a repeating unit shown as a formula (I):

in the formula (I), R¹、R²Each independently selected from hydrogen, substituted or unsubstituted alkyl; r³、R⁴、R⁵Each independently selected from substituted or unsubstituted alkyl; x is a natural number; y is a positive integer.

2. A polybenzimidazole derivative according to claim 1, characterized in that: in the polybenzimidazole derivative represented by the formula (I), R¹、R²Each independently selected from hydrogen or n-pentyl; r³、R⁴、R⁵Is n-pentyl.

3. A polybenzimidazole derivative according to claim 1, characterized in that: in the polybenzimidazole derivative shown in the formula (I), the end group comprises a structure shown in a formula (II) or a formula (III):

4. a polybenzimidazole derivative according to claim 1, characterized in that: the number average molecular weight of the polybenzimidazole derivative is 2500 g/mol-5500 g/mol.

5. The process for producing a polybenzimidazole derivative according to any one of claims 1 to 4, characterized by: the method comprises the following steps: mixing 3,3 ', 4, 4' -tetraaminobenzidine and fumaric acid, and reacting to obtain the polybenzimidazole derivative.

6. The method for producing a polybenzimidazole derivative according to claim 5, comprising: also included is a step of alkylating the polybenzimidazole derivative.

7. Use of a polybenzimidazole derivative according to any one of claims 1 to 4 in the field of fluorescent probes.

8. An entailment door, its characterized in that: the entailment gate comprises a polybenzimidazole derivative according to any one of claims 1 to 4.

9. A test paper is characterized in that: the test strip comprising the polybenzimidazole derivative according to any one of claims 1 to 4.

10. A thin layer chromatography plate, characterized in that: the thin layer chromatography plate comprises the polybenzimidazole derivative according to any one of claims 1 to 4.