阅读说明：本技术 一种金属锌配位聚合物的制备方法及其应用 (Preparation method and application of metal zinc coordination polymer ) 是由 王炎 于 2021-08-13 设计创作，主要内容包括：本发明提供了一种金属锌配位聚合物的制备方法及其应用,金属锌配位聚合物化学简式为：[Zn-(2)(μ-(2)-bcpb)(μ-(4)-bcpb)(2,2’-bipy)-(2)]-(n),其中bcpb～(2-)为去质子化的1,4-双(2’-羧基苯氧基)苯,2,2’-bipy为2,2’-联吡啶。该金属锌配位聚合物通过水热方法制得,即：按摩尔比为2:2:1将Zn(NO-(3))-(2)·6H-(2)O、2,2’-联吡啶和1,4-双(2’-羧基苯氧基)苯加入到聚四氟乙烯管中,再加入1mL的N,N-二甲基甲酰胺和6mL水,用0.25mol/L的NaOH调节pH至5.0,将聚四氟乙烯管放入到反应釜中以413K反应3天。冷却到室温后收集到无色透明的块状晶体,蒸馏水洗涤,真空干燥即可。该金属锌配位聚合物是具有双核锌次级结构单元的二维结构。其在水溶液中对丙酮和二价铜离子具有很好的选择性检测,且该配合物至少能重复五次以上使用,可作为高效的检测丙酮和二价铜离子的荧光探针。(The invention provides a preparation method and application of a metal zinc coordination polymer, wherein the chemical formula of the metal zinc coordination polymer is as follows: [ Zn ] 2 (μ 2 ‑bcpb)(μ 4 ‑bcpb)(2,2'‑bipy) 2 ] n Wherein bcpb 2‑ For deprotonated 1, 4-bis (2' -carboxyphenoxy) benzene, 2,2' -bipy is 2,2' -bipyridine. The metal zinc coordination polymer is prepared by a hydrothermal method, namely: zn (NO) is added according to the molar ratio of 2:2:1 3 ) 2 ·6H 2 O, 2 '-bipyridine and 1, 4-bis (2' -carboxyphenoxy) benzene were added to a polytetrafluoroethylene tube, 1mL of N, N-dimethylformamide and 6mL of water were added, the pH was adjusted to 5.0 with 0.25mol/L NaOH, and the polytetrafluoroethylene tube was placed in a reaction vessel and reacted at 413K for 3 days. Cooling to room temperature, collecting colorless transparent block crystal, washing with distilled water, and vacuum drying. The metal zinc coordination polymer has a binuclear zinc secondary structureA two-dimensional structure of cells. The complex has good selectivity for detecting acetone and divalent copper ions in aqueous solution, can be used repeatedly at least five times, and can be used as a fluorescent probe for efficiently detecting acetone and divalent copper ions.)

1. A metal zinc coordination polymer is characterized in that the chemical formula is as follows: [ Zn ]₂(μ₂-bcpb)(μ₄-bcpb)(2,2'-bipy)₂]_nWherein bcpb^2-Is deprotonated 1, 4-bis (2' -carboxyphenoxy) benzene, 2,2' -bipy is 2,2' -bipyridine, n is the degree of polymerization, and the structural formula is as follows:

2. the method for preparing a zinc metal coordination polymer according to claim 1, comprising the steps of:

step 1: zn (NO) is added according to the molar ratio of 2:2:1₃)₂·6H₂Adding O, 2 '-bipyridyl and 1, 4-bis (2' -carboxyphenoxy) benzene into a polytetrafluoroethylene tube, adding 1mL of N, N-dimethylformamide and 6mL of water, and adjusting the pH value to 5.0 by using a NaOH solution;

step 2: and (3) placing the polytetrafluoroethylene tube in a stainless steel reaction kettle, sealing, reacting for 3 days at 413K, cooling to room temperature to separate out colorless transparent blocky crystals, washing with distilled water, and drying in vacuum to obtain the metal zinc coordination polymer.

3. The method of claim 2, wherein the concentration of the NaOH solution in step 1 is 0.25 mol/L.

4. The use of a metal zinc coordination polymer according to claim 1, wherein said metal zinc coordination polymer is used as a fluorescent probe for the detection of acetone and cupric ions in water.

Technical Field

The invention relates to the field of zinc coordination polymers, in particular to a preparation method and application of a metal zinc coordination polymer.

Background

Acetone is oneThe aromatic liquid is inflammable, easy to volatilize, easy to dissolve in water and methanol and active in chemical property. Is harmful to human body, and is easy to cause poisoning by long-term contact with acetone, which is often manifested as shortness of breath, nausea, vomiting and headache. Copper is a metal with a purple-red luster and a density of 8.92g/cm³. Copper exists mainly in three forms of metallic copper, monovalent copper and divalent copper in nature, and is used as a trace element necessary for a human body, and trace copper ions are beneficial to the human body. However, excessive copper ions in the human body cause cirrhosis, diarrhea, vomiting, dyskinesia, and sensory neuropathy. Therefore, the detection of acetone and divalent copper ions in drinking water and industrial wastewater is of great importance, and the fluorescent probe with the advantages of simple synthesis, high identification speed, low cost and the like becomes a hotter detection method researched at present. Therefore, the design and synthesis of fluorescent probes for acetone and divalent copper ions have very important significance.

Disclosure of Invention

The invention aims to provide a preparation method of a coordination polymer with a two-dimensional structure constructed on the basis of transition metal zinc (II), 1, 4-bis (2 '-carboxyphenoxy) benzene and 2,2' -bipyridyl, and application of the coordination polymer as a fluorescent probe for detecting acetone and divalent copper ions in an aqueous solution.

In order to realize the purpose, the invention is realized by the following technical scheme:

a metal zinc coordination polymer having the chemical formula: [ Zn ]₂(μ₂-bcpb)(μ₄-bcpb)(2,2'-bipy)₂]_nWherein bcpb^2-Is deprotonated 1, 4-bis (2' -carboxyphenoxy) benzene, 2,2' -bipy is 2,2' -bipyridine, n is the degree of polymerization, and the structural formula is as follows:

the metal zinc complex belongs to a triclinic system, and the space group is P1. The asymmetric unit is composed of one Zn atom, one 2,2' -bipyridine and two 1/2 main ligands. Zn atoms are penta-coordinated and form a triangular biconical shapeZnO₃N₂The unit, Zn atom coordinates with three oxygen atoms from different ligand carboxylic acids and two N atoms from 2,2' -bipyridine, respectively, forming a distorted trigonal bipyramidal geometric configuration. The bond length of Zn-O bond is in the range ofBetween, the bond lengths of the Zn-N bonds are 2.1393(18) andthe included angle of O-Zn-O is 76.05(6) -133.10(6) °. X-ray confirmed powder diffraction confirmed that the crystalline sample was homogeneous and stable.

The invention provides a preparation method of the metal zinc coordination polymer, which comprises the following steps:

step 1: zn (NO) is added according to the molar ratio of 2:2:1₃)₂·6H₂Adding O, 2 '-bipyridyl and 1, 4-bis (2' -carboxyphenoxy) benzene into a polytetrafluoroethylene tube, adding 1mL of N, N-dimethylformamide and 6mL of water, and adjusting the pH value to 5.0 by using a NaOH solution;

step 2: and (3) placing the polytetrafluoroethylene tube in a stainless steel reaction kettle, sealing, reacting for 3 days at 413K, cooling to room temperature to separate out colorless transparent blocky crystals, washing with distilled water, and drying in vacuum to obtain the metal zinc coordination polymer.

Further, the concentration of the NaOH solution in the step 1 is 0.25 mol/L.

The invention also provides application of the metal zinc coordination polymer as a fluorescent probe to detection of acetone and divalent copper ions in water.

Compared with the prior art, the invention has the following beneficial effects:

the zinc coordination polymer is synthesized under hydrothermal conditions, and has the advantages of simple preparation process, high yield and high purity. Thermogravimetric analysis shows that the structure decomposes above 243 ℃ and the practical temperature range is below 243 ℃. The zinc coordination polymer is constructed based on 1, 4-bis (2 '-carboxyphenoxy) benzene, 1, 4-bis (2' -carboxyphenoxy) benzene is a semi-rigid ligand, and a benzene ring can surround etherThe bonded oxygen atoms are free to rotate and the oxygen atom in the center of the ligand can donate electrons to the benzene ring. Wherein, mu₄-COO^-The carboxyl group connects two zinc ions to form [ Zn ]₂(μ₄-COO)(2,2'-bipy)₂]²⁺A dual core secondary building block. The complex has unique fluorescence selectivity on acetone and divalent copper ions in aqueous solution as a fluorescent probe, can effectively and selectively detect the acetone and the divalent copper ions, has the detection limit of 0.0150 percent M on the acetone and has the detection limit of Cu²⁺Has a detection limit of 7.2X 10^-7M, and the complex can be used repeatedly at least five times. The complex is in aqueous solution to acetone and Cu²⁺Has higher sensitivity and lower detection limit, thereby having greater application prospect in the field of fluorescent probe detection.

Drawings

FIG. 1 is a crystal structure diagram of a zinc complex of the present invention.

FIG. 2 is an X-ray powder diffraction pattern of a zinc complex of the present invention.

FIG. 3 is a thermogravimetric analysis of the zinc complex of the present invention.

FIG. 4 is a fluorescence spectrum of the zinc complex of the present invention after mixing with various organic small molecule solutions in an aqueous solution.

FIG. 5 is a fluorescence spectrum of a zinc complex of the present invention added with acetone of different contents in an aqueous solution.

FIG. 6 is a linear calibration curve of fluorescence of the zinc complex of the present invention with different amounts of acetone added to the aqueous solution.

FIG. 7 is a fluorescence spectrum of a zinc complex of the present invention mixed with various metal cation solutions in an aqueous solution.

FIG. 8 shows that Cu with different concentrations is added into an aqueous solution by the zinc complex of the invention²⁺Fluorescence spectrum of (2).

FIG. 9 shows that the zinc complex of the present invention is added with Cu of different concentrations in an aqueous solution²⁺Linear calibration curve of fluorescence.

FIG. 10 shows the detection of Cu by the zinc complex of the present invention²⁺Five cycles of the experiment fluorescence spectrogram.

Detailed Description

The following examples are given in the detailed description and the specific operation on the premise of the technical solutions of the present invention, but do not limit the protection scope of the patent of the present invention, and all technical solutions obtained by using equivalent alternatives or equivalent variations should fall within the protection scope of the present invention.

Example 1

Preparation of Zinc coordination polymers

H is to be₂bcpb(17.5mg,0.05mmol)、Zn(NO₃)₂·6H₂O (29.7mg,0.1mmol), 2' -bipy (15.6mg,0.1mmol) were added to a 25mL polytetrafluoroethylene tube, and DMF (1.0mL) and H were added₂O (6.0mL), adjusted to pH 5.0 with 0.5mL of 0.25mol/L NaOH solution, transferred to the reaction kettle and reacted in an oven at 413K for 72 hours, then filtered, dried and cooled to room temperature to give colorless and transparent crystals in the form of a lump with a yield of 55.9%.

And (3) determining the crystal structure of the zinc complex:

the crystal structure is measured by X-ray diffraction, Mo-K alpha rays are monochromatized by a Bruker D8Venture detector through a graphite monochromator in a scanning mode of omega, and the temperature of collected data is 293K. The raw data was restored by SAINT and then absorption corrected using SADABS. The crystal structure is obtained by directly solving SHELXL-97. The detailed crystal determination data are shown in table 1. The crystal structure is shown in a one-dimensional structure diagram in figure 1.

TABLE 1 crystallographic data for Zinc complexes

Powder diffraction:

the X-ray powder diffraction is shown in fig. 2, and the experimental diffraction pattern is consistent with the powder diffraction pattern simulated according to the crystal structure, which indicates that the phase of the crystal sample is uniform.

Thermogravimetric analysis of zinc coordination polymer:

the results of thermogravimetric analysis show that the main structure of the zinc coordination polymer is decomposed at the temperature of 243 ℃ or higher, which shows that the zinc coordination polymer of the invention is suitable for the temperature below 243 ℃, and the results are shown in figure 3.

Example 2 Selective recognition of acetone in Water by Metal Zinc Complex as fluorescent Probe

Firstly, taking different organic small molecule solutions (methanol, ethanol, N-dimethylformamide, N-dimethylacetamide, ethylene glycol, acetonitrile, acetone and dimethyl sulfoxide), dissolving 5mg of the metal zinc complex in 50mL of water, performing ultrasonic treatment for 30min, and precipitating for three days. And (3) taking supernatant liquid, respectively adding different organic small molecule solutions, and measuring the fluorescence emission intensity of the supernatant liquid under the excitation of 250nm, wherein the complex has unique fluorescence selectivity on acetone as shown in figure 4.

Example 3 sensitivity of Metal Zinc Complex as fluorescent Probe for identifying acetone in Water

5mg of the metal zinc complex was dissolved in 50mL of water, sonicated for 30min, and allowed to settle for three days, to form a suspension containing the metal zinc complex. The supernatant was taken and the suspension of the complex showed very strong fluorescence at 324nm, measured under excitation at a wavelength of 250 nm. As can be seen from the titration curve of FIG. 5, the fluorescence intensity of the solution gradually decreased as the acetone concentration in the system increased. Furthermore, as shown in fig. 6, at low concentrations, the quenching effect can be fitted as a function of: i is₀/I＝1.9525V_Acetone/H2O+0.9446，I₀Calculating the correlation coefficient R for the initial luminous intensity and I for the luminous intensity after adding acetone²Has a value of 0.9812. LOD 3S based on equation_B/S(S_BS is the slope of the linear relationship of acetone content to fluorescence intensity plotted against the standard deviation of five blank measurements relative to aqueous solution) was calculated to have a detection limit of 0.0150% M for acetone.

Example 4 Metal Zinc Complex as fluorescent Probe for Cu in Water²⁺Selective identification of

First, 5mL of the solution was prepared at a concentration of 1X 10^-3Difference in mol/LCation solution (Na)⁺、Fe³⁺、Cr³⁺、Cd²⁺、Cu²⁺、K⁺、Mg²⁺、Ni²⁺、Co²⁺、Ba²⁺、Zn²⁺、Mn²⁺、Ca²⁺) Then, 5mg of the metal zinc complex was dissolved in 50mL of water, sonicated for 30min, and precipitated for three days. Collecting supernatant, adding metal cation solution, measuring fluorescence emission intensity under 250nm excitation, and adding Cu as shown in FIG. 7²⁺Can quench the fluorescence of the complex.

Example 5 identification of Cu in Water by Metal Zinc Complex as fluorescent Probe²⁺Sensitivity of (2)

5mg of this metal zinc complex was dissolved in 50mL of water, sonicated for 30min, and allowed to settle for three days to form a complex-containing suspension. The supernatant was taken and the suspension of the complex showed very strong fluorescence at 324nm, measured under excitation at a wavelength of 250 nm. As can be seen from the titration curves of FIG. 8, with Cu in the system²⁺The fluorescence intensity of the solution gradually decreases with increasing concentration. Furthermore, as shown in FIG. 9, at low concentrations, the quenching effect can be handled by the Stern-Volmer equation: i is₀/I＝1+K_SV×[M]，I₀Is the initial fluorescence intensity of the complex, I is the addition of Cu²⁺Fluorescence intensity of the post-complex, [ M]Is Cu²⁺Concentration of (A), K_SVIs the quenching constant. K_SVCalculated value of (A) is 5.7X 10⁴M^-1. Obtained by calculating the detection limit, the complex is used for Cu²⁺Has a detection limit of 7.2X 10^-7And M. Illustrating the fluorescent probe to Cu in an aqueous solution²⁺Has higher sensitivity and lower detection limit, thereby having larger application prospect.

Example 6 identification of Cu in Water by Metal Zinc Complex as fluorescent Probe²⁺Recycling property of

5mg of the fluorescent probe was immersed in 10mL of an aqueous solution, and after three days, the supernatant and the supernatant were measured separately and Cu was added²⁺Centrifuging, washing, drying, adding 10mL water, ultrasonic treating for 30min, precipitating for three days, and measuring supernatant and supernatantLiquid plus Cu²⁺The cycle is five times. FIG. 10 is a fluorescence spectrum of the fluorescent probe after five cycles, illustrating the recyclability of the probe.