Dihydrate 5-[(1E)-(3, 5-dicarboxylphenyl) ethylazenyl] benzene-1, 3-dicarboxylic acid-di (1, 10-phenanthroline) zinc coordination polymer

Abstract

The invention relates to a dihydrate 5-[(1E)-(3, 5-dicarboxylphenyl) ethylazenyl] benzene-1, 3-dicarboxylic acid-di (1, 10-phenanthroline) zinc coordination polymer, and belongs to the field of fluorescent probes. The invention aims to provide a novel compound. The molecular formula of the polymer is C40H26N4O10Zn2. The structural formula of the polymer is shown in the description. The method comprises the following steps: 1, adding an ethanol aqueous solution into a mixture of 5-nitroisophthalic acid, zinc powder and sodium hydroxide, heating, refluxing, stirring for reaction, filtering, soaking a filter cake in a sodium hydroxide solution, stirring for dissolution, carrying out suction filtration, adjusting the pH value, and carrying out suction filtration and drying to obtain a 5-[(1E)-(3, 5-dicarboxyphenyl) ethyl azenyl] benzene-1, 3-dicarboxylic acid ligand; and 2, adding the ligand obtained in the step 1 and 1, 10-phenanthroline into a mixed solvent of N, N '-dimethylformamide, acetonitrile and water, carrying out a stirring reaction, adjusting the pH value until the precipitate is dissolved, carrying out continuous stirring, transferring the obtained solution into a reaction kettle, carrying out programmed heating to obtain a golden needle-shaped crystal, washing, filtering, and drying to obtain the product. The invention is applied to the field of fluorescent probes.

Description

Technical Field

[0001] This invention belongs to the field of fluorescent probes, specifically relating to a dihydrated 5-[(1E)-(3,5-dicarboxyphenyl)ethazenoyl]benzene-1,3-dicarboxylic acid-bis(1,10-o-phenanthroline)zinc coordination polymer, its preparation method, and its application. Background Technology

[0002] Metal-organic coordination polymers have attracted widespread attention from researchers in recent years due to their unique physical, chemical, and biological properties. These materials have shown great potential in fields such as magnetic materials, gas adsorption, hydrogen storage, catalysis, and biomedicine, especially in the application of fluorescent probes. Studies have shown that the high designability of coordination polymer structures endows them with research value in multiple disciplines, making them one of the current research hotspots in materials science.

[0003] Metal ions play an irreplaceable and vital role in industrial production, the ecological environment, and human life activities, among which Fe... 3+ Ions, as essential trace elements, play a central role in various biochemical processes within cells. Fe 3+ Fe is widely involved in key life activities such as DNA and RNA synthesis, electron transport in the mitochondrial respiratory chain, and oxygen storage and transport. It is also an important component of many enzymes and proteins, and is crucial for maintaining normal cellular metabolism and physiological functions. However, Fe... 3+ The levels of ions in the body must be maintained within a suitable range; both excess and deficiency can have serious consequences for human health. When Fe... 3+ When the concentration of Fe is too high, it can catalyze the generation of reactive oxygen species through a Fenton-like reaction, thereby triggering oxidative damage to nucleic acids, proteins, and lipids, leading to cell dysfunction and even apoptosis. Studies have shown that Fe... 3+ Excessive accumulation is closely associated with various neurodegenerative diseases, among which Alzheimer's disease is thought to be significantly linked to iron-induced oxidative stress. Conversely, when the body lacks Fe... 3+ When Fe ions are present, they affect hemoglobin synthesis, reduce the body's oxygen-carrying capacity, and thus lead to a series of health problems such as anemia, decreased immune function, and metabolic disorders. Therefore, achieving Fe... 3+ Rapid, sensitive, and accurate detection of ions in the environment and biological systems has significant theoretical and practical value for disease prevention, environmental monitoring, and life science research.

[0004] Currently, Fe 3+The detection of ions mainly relies on large, sophisticated instruments such as ICP and atomic emission spectroscopy. These methods are typically complex to operate, require expensive equipment, and cumbersome sample pretreatment. To meet practical application needs, there is an urgent need to develop a simple and efficient detection technique for the rapid analysis of metal ions. Fluorescent probe technology is considered an ideal detection method due to its ease of operation and high sensitivity, with fluorescent sensors based on metal-organic coordination polymers being regarded as a particularly promising research direction. However, how to construct Fe ions with high selectivity, high sensitivity, and low detection limits through a simple synthetic method remains a challenge. 3+ Fluorescent sensing materials remain a research problem that urgently needs to be solved. Summary of the Invention

[0005] This invention aims to solve the existing Fe 3+ The detection of Fe ions is characterized by complex operation, expensive equipment, and cumbersome sample pretreatment. This paper presents a novel compound, a dihydrated 5-[(1E)-(3,5-dicarboxyphenyl)ethazenoyl]phenyl-1,3-dicarboxylic acid-bis(1,10-o-phenanthroline)zinc dicopolymer, along with its preparation method and applications. This organometallic coordination polymer can be used as a fluorescent probe material for the detection of Fe ions. 3+ Ions are detected.

[0006] To address the aforementioned technical problems, the present invention adopts the following technical solution: The purpose of this invention is to provide a dihydrated 5-[(1E)-(3,5-dicarboxyphenyl)ethazenoyl]phenyl-1,3-dicarboxylic acid-bis(1,10-o-phenanthroline)zinc dicopolymer with the molecular formula C 40 H 26 N4O 10 Zn2, its structural formula is: .

[0007] Further specifying, the dihydrated 5-[(1E)-(3,5-dicarboxyphenyl)ethazenoyl]benzene-1,3-dicarboxylic acid-bis(1,10-o-phenanthroline)zinc-coordinated polymer is a triclinic crystal system, space group P-1, with the following cell parameters: a = 10.1867(4) Å, b = 12.5134(5) Å, c = 18.9064(7) Å, α = 108.397(3)°, β = 91.571(3)°, γ = 98.753(3)°, V = 2252.88(16) Å 3 Z = 2, ρ calc = 1.303 g / cm 3 μ = 1.122 mm -1F(000) = 898.0, R int = 0.0290, R sigma = 0.0481, Goodness-of-fit on F 2 = 1.024, where I ≥ 2 σ ( I The final R-factors for the full data range are R1 = 0.0618 and wR2 = 0.1643, and the R-factors for the entire data range are R1 = 0.0832 and wR2 = 0.1816.

[0008] The ligand of the dihydrated 5-[(1E)-(3,5-dicarboxyphenyl)ethazenoyl]phenyl-1,3-dicarboxylic acid-bis(1,10-o-phenanthroline)zinc dicosinate coordination polymer is 5-[(1E)-(3,5-dicarboxyphenyl)ethazenoyl]phenyl-1,3-dicarboxylic acid; the metal center is zinc, and the simplest formula of this organometallic coordination polymer is C 20 H 13 N2O5Zn, with a molecular weight of 881.41.

[0009] Another object of the present invention is to provide a method for preparing the above-mentioned dihydrated 5-[(1E)-(3,5-dicarboxyphenyl)ethazenoyl]benzene-1,3-dicarboxylic acid-bis(1,10-o-phenanthroline)zinc dicopolymer.

[0010] A method for preparing a dihydrated 5-[(1E)-(3,5-dicarboxyphenyl)ethazinyl]phenyl-1,3-dicarboxylic acid-bis(1,10-o-phenanthroline)dizinc coordination polymer includes the following steps: Step 1: Mix 5-nitroisophthalic acid, zinc powder and sodium hydroxide, add an aqueous ethanol solution, and reflux with magnetic stirring in an oil bath. After the reaction is complete, cool to room temperature, filter, soak the filter cake in sodium hydroxide solution, stir to dissolve, filter under vacuum, adjust the pH of the obtained filtrate to 2.8-3.2 with hydrochloric acid to obtain a large amount of pale yellow precipitate, dry the filter cake obtained by vacuum filtration to obtain 5-[(1E)-(3,5-dicarboxyphenyl)ethazinyl]phenyl-1,3-dicarboxylic acid ligand.

[0011] Step 2: ZnCl2·6H2O, 5-[(1E)-(3,5-dicarboxyphenyl)ethazinyl]benzene-1,3-dicarboxylic acid ligand, and 1,10-o-phenanthroline were mixed and then added to a mixed solvent of N,N′-dimethylformamide, acetonitrile, and water. The mixture was stirred, and the pH was adjusted to 4.8-5.2 with HCl. The mixture was stirred continuously until a yellow-green transparent solution was obtained. This solution was then transferred to a reaction vessel with a polytetrafluoroethylene liner. The temperature was programmed and increased. After the reaction was completed, the mixture was cooled to room temperature to obtain golden-yellow needle-like crystals. These crystals were washed, filtered, and then naturally dried to obtain the dihydrated 5-[(1E)-(3,5-dicarboxyphenyl)ethazinyl]benzene-1,3-dicarboxylic acid-bis(1,10-o-phenanthroline)dizinc coordination polymer.

[0012] Further specifying, the molar ratio of 5-nitroisophthalic acid, zinc powder and sodium hydroxide in step one is 1:(2~2.2):(2~2.2).

[0013] Further specifying, in step one, the concentration of the sodium hydroxide solution is 1 mol / L.

[0014] To further specify, in step one, the concentration of hydrochloric acid is 3 mol / L.

[0015] Further specifying, in step one, the volume ratio of water to ethanol is 1:(2.4 to 2.6).

[0016] To further specify, in step one, the oil bath temperature is 90℃.

[0017] Further specifying, in step one, drying is performed at 45°C.

[0018] Further specifying, in step two, the molar ratio of ZnCl2·6H2O, 5-[(1E)-(3,5-dicarboxyphenyl)ethazenoyl]benzene-1,3-dicarboxylic acid ligand, and 1,10-o-phenanthroline is 3:1:(2-2.2).

[0019] Further specifying, in step two, the volume molar ratio of N,N′-dimethylformamide, acetonitrile, and water is 3:3:(2 to 2.2).

[0020] Further specifying, in step two, the concentration of hydrochloric acid is 1 mol / L.

[0021] Further specifying, in step two, the temperature is increased to 85°C at a rate of 3°C / min and held for 12 hours.

[0022] The reaction equation of this invention is as follows: The reaction equation for the preparation of the 5-[(1E)-(3,5-dicarboxyphenyl)ethazenoyl]benzene-1,3-dicarboxylic acid ligand in step one is as follows:

[0023] The reaction equation for the preparation of step two, the dihydrated 5-[(1E)-(3,5-dicarboxyphenyl)ethazenoyl]benzene-1,3-dicarboxylic acid-bis(1,10-o-phenanthroline)zinc dicopolymer, is as follows: Furthermore, the use of the dihydrated 5-[(1E)-(3,5-dicarboxyphenyl)ethazenoyl]benzene-1,3-dicarboxylic acid-bis(1,10-o-phenanthroline)zinc dicopolymer of the present invention is also provided, in Fe 3+ Applications in ion detection.

[0024] The dihydrated 5-[(1E)-(3,5-dicarboxyphenyl)ethazinyl]phenyl-1,3-dicarboxylic acid-bis(1,10-phenanthroline)zinc dicopolymer of this invention is a polymeric complex formed by zinc with 5-[(1E)-(3,5-dicarboxyphenyl)ethazinyl]phenyl-1,3-dicarboxylic acid as a ligand. In this coordination polymer, the asymmetric structure contains two crystallographically distinct Zn(II) ions: Zn1 and Zn2. The coordination environments of the two Zn(II) ions are different; Zn1 has a coordination number of 6, forming a distorted octahedral configuration; the other Zn2 cation has a coordination number of 5, forming a trigonal bipyramidal configuration. Although the bond lengths and bond angles between the two Zn ions and their surrounding coordinating atoms differ, they are all within the Zn-O / N range reported in the literature. Along the a-axis, the complex is connected end-to-end with two Zn1 and two Zn2 molecules through monodentate coordination and bidentate chelation, respectively, forming a one-dimensional chain structure. The o-phenanthroline molecules in the four adjacent one-dimensional chains are parallel and overlap each other. Through this intermolecular π-π stacking interaction, the adjacent one-dimensional chain molecules are connected to form a two-dimensional supramolecular structure. Then, through the π-π stacking interaction between the closely spaced 5-[(1E)-(3,5-dicarboxyphenyl)ethazenoyl]benzene-1,3-dicarboxylic acid ligands, the two-dimensional supramolecular structure of the complex is connected into a three-dimensional supramolecular structure.

[0025] Compared with the prior art, the present invention has the following beneficial effects: The metal-organic coordination polymer prepared by the method of the present invention is a single crystal with a complete crystal structure. The yield of the product obtained by the method of the present invention is high, reaching 38.8%.

[0026] The metal-organic coordination polymer underwent performance testing for Fe. 3+ It exhibits high selectivity and sensitivity, and has good anti-interference ability against other metal ions.

[0027] For a deeper understanding of the features and technical content of this invention, please refer to the accompanying detailed description and drawings. It should be noted that the drawings are provided for illustrative purposes only and are not intended to limit the scope of the invention. Attached Figure Description

[0028] Figure 1 The crystal structure diagram (ball-and-stick diagram) of the dihydrate 5-[(1E)-(3,5-dicarboxyphenyl)ethazenoyl]benzene-1,3-dicarboxylic acid-bis(1,10-o-phenanthroline)zinc dicosinate coordination polymer of the present invention is shown. Figure 2 This is a three-dimensional crystal diagram (ball-and-stick diagram) of the dihydrated 5-[(1E)-(3,5-dicarboxyphenyl)ethazenoyl]benzene-1,3-dicarboxylic acid-bis(1,10-o-phenanthroline)zinc dicosinate coordination polymer of the present invention. Figure 3 The infrared spectrum of the ligand and complex prepared in Example 1; Figure 4 The dihydrated 5-[(1E)-(3,5-dicarboxyphenyl)ethazenoyl]benzene-1,3-dicarboxylic acid-bis(1,10-o-phenanthroline)zinc coordination polymer prepared in Example 1 is used to coordinate Fe 3+ Selectivity spectrum for ion detection; Figure 5 The dihydrated 5-[(1E)-(3,5-dicarboxyphenyl)ethazenoyl]benzene-1,3-dicarboxylic acid-bis(1,10-o-phenanthroline)zinc coordination polymer prepared in Example 1 is used to coordinate Fe 3+ Results of anti-interference experimental structure for ion detection; Figure 6 The dihydrated 5-[(1E)-(3,5-dicarboxyphenyl)ethazenoyl]benzene-1,3-dicarboxylic acid-bis(1,10-o-phenanthroline)zinc coordination polymer prepared in Example 1 is used to coordinate Fe 3+ Fluorescence spectrum for ion sensitivity detection. Detailed Implementation

[0029] The present invention will be described in detail below with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but should not be considered as limiting the present invention. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0030] Example 1: The preparation method of the dihydrated 5-[(1E)-(3,5-dicarboxyphenyl)ethazenoyl]benzene-1,3-dicarboxylic acid-bis(1,10-o-phenanthroline)zinc dicopolymer in this example is carried out according to the following steps: Step 1: Preparation of 5-[(1E)-(3,5-dicarboxyphenyl)ethazenoyl]benzene-1,3-dicarboxylic acid ligand: Three solids, 5-nitroisophthalic acid (7.5 g, 35.5 mmol), zinc powder (4.64 g, 71.4 mmol), and sodium hydroxide (2.86 g, 71.4 mmol), were added to a 500 mL round-bottom flask. 178.6 mL of ethanol and 71.4 mL of water were accurately measured, mixed, and added to the mixture of the three solids. The mixture was refluxed in an oil bath with a magnetic stirrer at 90 °C for 12 hours. After the reaction was complete, the mixture was cooled to room temperature and filtered. The filter cake was then immersed in 180 mL of sodium hydroxide solution (1 mol / L) and stirred for a long time until dissolved. The mixture was then filtered, and the pH of the filtrate was adjusted to approximately 3 with hydrochloric acid (3 mol / L), resulting in a large amount of pale yellow precipitate. The filter cake was dried in an oven at 45 °C to obtain a beige product, 5-[(1E)-(3,5-dicarboxyphenyl)ethazenoyl]benzene-1,3-dicarboxylic acid ligand, with a calculated yield of 70.1%. The reaction equation is as follows:

[0031] Step 2: Preparation of dihydrated 5-[(1E)-(3,5-dicarboxyphenyl)ethazenoyl]benzene-1,3-dicarboxylic acid-bis(1,10-o-phenanthroline)zinc dicopolymer: ZnCl2·6H2O (0.15 mmol, 0.0203 g), ligand 5-[(1E)-(3,5-dicarboxyphenyl)ethazenoyl]benzene-1,3-dicarboxylic acid (0.05 mmol, 0.0179 g), and 1,10-o-phenanthroline (0.1 mmol, 0.0197 g) were mixed and then added to a mixed solvent of N,N′-dimethylformamide (DMF, 3 mL), acetonitrile (3 mL), and water (2 mL). The mixture was stirred for 35 min and then diluted with HCl (1... The pH was adjusted by adding mol / L of zinc until the precipitate was just completely dissolved. At this point, the pH was approximately 5 as measured by a pH meter. The mixture was stirred continuously for 30 minutes, resulting in a yellowish-green transparent solution. This solution was transferred to a 20 mL reactor lined with polytetrafluoroethylene (PTFE). The temperature was increased to 85 °C at a rate of 3 °C / min and maintained for 12 hours. After cooling to room temperature, golden-yellow needle-like crystals were obtained. These crystals were washed, filtered, and then allowed to air dry. The yield was 38.8% (calculated as Zn). The reaction equation is as follows:

[0032] The structure of this crystal was determined using an X-ray single-crystal diffractometer and corresponding software. X-ray single-crystal diffraction showed that the compound belongs to the triclinic crystal system, space group P-1, with the following cell parameters: a = 10.1867(4) Å, b = 12.5134(5) Å, c = 18.9064(7) Å, α = 108.397(3)°, β = 91.571(3)°, γ = 98.753(3)°, V = 2252.88(16) Å.3 Z = 2, ρ calc = 1.303 g / cm 3 μ = 1.122 mm -1 F(000) = 898.0, R int = 0.0290, R sigma = 0.0481, Goodness-of-fit on F 2 = 1.024, where I ≥ 2 σ ( I The final R-factors for the first time were R1 = 0.0618 and wR2 = 0.1643, while the R-factors for the entire data range were R1 = 0.0832 and wR2 = 0.1816. Its chemical formula is C. 40 H 26 N4O 10 Zn2.

[0033] The infrared spectrum of the product prepared in this embodiment is as follows: Figure 3 As shown, at 3380cm -1 The peaks on the left and right are the stretching vibration peaks of -OH; 1625 cm⁻¹ -1 The absorption peaks on the left and right sides correspond to the C=O stretching vibration peaks; 1430 cm⁻¹ -1 The peaks on the left and right correspond to the -N=N- stretching vibration, which is the same as the -N=N- vibration absorption peak (1439 cm⁻¹) of the free ligand 5-[(1E)-(3,5-dicarboxyphenyl)ethazenoyl]phenyl-1,3-dicarboxylic acid. -1 Very close; 1565cm -1 and 1430cm -1 The peaks on the left and right represent skeletal vibrations of the benzene ring. The IR spectrum of the complex essentially includes all the major vibrational peaks of the H4L ligand, with an additional peak at 1518 cm⁻¹. -1 The peaks on the left and right are attributed to the C=N skeletal vibrations of 1,10-phenanthroline, indicating that 1,10-phenanthroline has successfully coordinated with the metal.

[0034] Different concentrations of metal ions (K) at 0.1 mol / L were used. + Na + Ca 2+ Cu 2+ Zn 2+ Co 2+ Ni 2+ Fe 3+ Hg 2+ Cd 2+ Pb 2+ Cr 3+A total of 12 types were added to 30 μL of a suspension of 5-[(1E)-(3,5-dicarboxyphenyl)ethazenoyl]benzene-1,3-dicarboxylic acid-bis(1,10-o-phenanthroline)zinc dicosinate coordination polymer dihydrate, and fluorescence intensity changes were recorded using a fluorescence spectrometer.

[0035] Dihydrated 5-[(1E)-(3,5-dicarboxyphenyl)ethazenoyl]phenyl-1,3-dicarboxylic acid-bis(1,10-o-phenanthroline)zinc dicopolymer for Fe 3+ Selectivity spectra for ion detection are as follows Figure 4 As shown, by Figure 4 It can be seen in K + Na + Ca 2+ Cu 2+ Zn 2+ Co 2+ Ni 2+ Fe 3+ Hg 2+ Cd 2+ Pb 2+ Cr 3+ Among 12 common metal ions, this metal-organic coordination polymer shows the best response to Fe. 3+ Ions exhibit the highest selectivity, resulting in almost complete fluorescence quenching.

[0036] 5-[(1E)-(3,5-dicarboxyphenyl)ethazenoyl]benzene-1,3-dicarboxylic acid-bis(1,10-o-phenanthroline)zinc dicopolymer Fe 3+ The anti-interference experimental results of ion detection are as follows: Figure 5 As shown. 1+Fe 3+ and 1+ interfering ion +Fe 3+ Add 32 μL of other interfering ions to a suspension of 5-[(1E)-(3,5-dicarboxyphenyl)ethazenoyl]benzene-1,3-dicarboxylic acid-bis(1,10-o-phenanthroline)zinc dihydrogen phosphate polymer dihydrate, and then add Fe... 3+ The ions introduced into the emulsion system of the dihydrated 5-[(1E)-(3,5-dicarboxyphenyl)ethazenoyl]benzene-1,3-dicarboxylic acid-bis(1,10-o-phenanthroline)zinc dicosinate coordination polymer achieved the same concentration as other ions in the final mixture. The results indicate that Fe... 3+ The fluorescence quenching effect of the ion-paired 5-[(1E)-(3,5-dicarboxyphenyl)ethazenoyl]benzene-1,3-dicarboxylic acid-bis(1,10-o-phenanthroline)zinc dicosinate coordination polymer is almost unaffected by interfering metal ions.

[0037] 5-[(1E)-(3,5-dicarboxyphenyl)ethazenoyl]benzene-1,3-dicarboxylic acid-bis(1,10-o-phenanthroline)zinc dicopolymer Fe 3+ Fluorescence spectrum for ion sensitivity detection is shown below Figure 6 As shown. The results indicate that this compound is effective against Fe. 3+ Ions have the characteristics of low detection limit and high sensitivity.

[0038] The specific embodiments of the present invention have been described in detail above. It should be noted that the present invention is not limited to the specific embodiments described above. Various modifications or alterations can be made by those skilled in the art without departing from the scope of protection defined by the claims, and all such modifications or alterations fall within the scope of the present invention.

Claims

1. A dihydrated 5-[(1E)-(3,5-dicarboxyphenyl)ethazenoyl]benzene-1,3-dicarboxylic acid-bis(1,10-o-phenanthroline)zinc dicopolymer, characterized in that, The structural formula of the polymer is: 。 2. The polymer according to claim 1, characterized in that, The polymer is triclinic, space group P-1, with the following cell parameters: a = 10.1867(4) Å, b = 12.5134(5) Å, c = 18.9064(7) Å, α = 108.397(3)°, β = 91.571(3)°, γ = 98.753(3)°, V = 2252.88(16) Å. 3 Z = 2, ρ calc = 1.303 g / cm 3 μ = 1.122 mm -1 F(000) = 898.0, R int = 0.0290, R sigma = 0.0481, Goodness-of-fit on F 2 =1.024, where I ≥ 2 σ ( I The final R-factors for the first time were R1 = 0.0618 and wR2 = 0.1643, while the R-factors for the entire data range were R1 = 0.0832 and wR2 = 0.1816.

3. The method for preparing the polymer according to claim 1 or 2, characterized in that, Includes the following steps: Step 1: Mix 5-nitroisophthalic acid, zinc powder, and sodium hydroxide, add an ethanol aqueous solution, and reflux with magnetic stirring in an oil bath. After the reaction is complete, cool to room temperature, filter, and immerse the filter cake in sodium hydroxide solution, stir to dissolve, and filter under vacuum. Adjust the pH of the filtrate to 2.8-3.2 with hydrochloric acid to obtain a large amount of pale yellow precipitate. Dry the filter cake obtained under vacuum to obtain 5-[(1E)-(3,5-dicarboxyphenyl)ethazenoyl]benzene-1,3-dicarboxylic acid ligand. Step 2: ZnCl2·6H2O, 5-[(1E)-(3,5-dicarboxyphenyl)ethazinyl]benzene-1,3-dicarboxylic acid ligand, and 1,10-o-phenanthroline were mixed and then added to a mixed solvent of N,N′-dimethylformamide, acetonitrile, and water. The mixture was stirred, and the pH was adjusted to 4.8-5.2 with HCl. The mixture was stirred continuously until a yellow-green transparent solution was obtained. This solution was then transferred to a reaction vessel with a polytetrafluoroethylene liner. The temperature was programmed and increased. After the reaction was completed, the mixture was cooled to room temperature to obtain golden-yellow needle-like crystals. These crystals were washed, filtered, and then naturally dried to obtain the dihydrated 5-[(1E)-(3,5-dicarboxyphenyl)ethazinyl]benzene-1,3-dicarboxylic acid-bis(1,10-o-phenanthroline)dizinc coordination polymer.

4. The method according to claim 3, characterized in that, In step one, the molar ratio of 5-nitroisophthalic acid, zinc powder and sodium hydroxide is 1:(2-2.2):(2-2.2).

5. The method according to claim 3, characterized in that, In step one, the volume ratio of water to ethanol is 1:(2.4 to 2.6).

6. The method according to claim 3, characterized in that, In step one, the oil bath temperature is 90℃.

7. The method according to claim 3, characterized in that, In step two, the molar ratio of ZnCl2·6H2O, 5-[(1E)-(3,5-dicarboxyphenyl)ethazenoyl]benzene-1,3-dicarboxylic acid ligand and 1,10-o-phenanthroline is 3:1:(2-2.2).

8. The method according to claim 3, characterized in that, The volume molar ratio of N,N′-dimethylformamide, acetonitrile, and water is 3:3:(2 to 2.2).

9. The method according to claim 3, characterized in that, Heat to 85℃ at a rate of 3℃ / min and hold for 12 hours.

10. The dihydrated 5-[(1E)-(3,5-dicarboxyphenyl)ethazenoyl]benzene-1,3-dicarboxylic acid-bis(1,10-o-phenanthroline)zinc dicopolymer as described in claim 1 for the detection of Fe 3+ ion.

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