CN112759769A

CN112759769A - Hexa-nuclear copper coordination polymer and preparation method and application thereof

Info

Publication number: CN112759769A
Application number: CN202011598787.8A
Authority: CN
Inventors: 刘霞霞; 冯思思; 朱苗力
Original assignee: Shanxi University
Current assignee: Shanxi University
Priority date: 2020-12-29
Filing date: 2020-12-29
Publication date: 2021-05-07
Anticipated expiration: 2040-12-29
Also published as: CN112759769B

Abstract

The invention relates to a copper coordination polymer, in particular to a six-core copper coordination polymer and a preparation method and application thereof. The invention provides a six-core copper coordination polymer, which has a molecular formula as follows: { [ Cu ]₆(H₂L)₄(4,4'‑bpy)₆(H₂O)₂]·16H₂O}_nIn which H is₅L represents 6- (3',4' -dicarboxyphenoxy) -2,3, 5-benzenetricarboxylic acid; 4,4'-bpy represents 4,4' -bipyridine, and n represents polymerization. The polymer is prepared by a hydrothermal method, and specifically Cu (NO)₃)₂·3H₂O、H₅Mixing the L ligand and the 4,4' -bpy ligand with water in proportion, placing the mixture in a polytetrafluoroethylene tube, sealing the polytetrafluoroethylene tube in a stainless steel reaction kettle, and keeping the temperature at 120 ℃ for 72 hours. And cooling at room temperature to obtain blue blocky crystals, washing with distilled water, drying in vacuum, and collecting to obtain the hexanuclear copper coordination polymer. The polymer copper ionFerromagnetic interaction exists between the two magnetic materials, and the magnetic material can be used as a molecular magnetic material.

Description

Hexa-nuclear copper coordination polymer and preparation method and application thereof

Technical Field

The invention relates to a copper coordination polymer, in particular to a magnetic six-nuclear copper coordination polymer constructed based on transition metal copper, 6- (3',4' -dicarboxyphenoxy) -2,3, 5-benzenetricarboxylic acid, 4' -bipyridine and water, and a preparation method and application thereof, and specifically relates to a six-nuclear copper coordination polymer and a preparation method and application thereof.

Background

With the development of society and the progress of science and technology, magnetic materials have been applied in various fields such as national defense, scientific research, high and new technology, daily life and the like. However, some applications of conventional magnetic materials in advanced technologies and advanced technologies are greatly limited. The molecular magnetic material is a novel material developed in recent decades, is used as a highly ordered molecular system, has structural diversity compared with the traditional magnet, and is easy to modify and cut molecules by a chemical method to change the magnetism of the molecules; diversity in magnetic properties; magnetic and other properties such as mechanical, optical, electrical, etc. may be combined; can be synthesized by a normal temperature or low temperature method; the magnet is easy to machine and form, and can be made into a plurality of devices which are difficult to realize by the traditional magnet; low density, etc. Due to the characteristics, the method has important application prospects in the fields of information storage technology, communication equipment, medical equipment, aerospace and the like, and becomes the focus of research of scientists.

Disclosure of Invention

In view of the above problems, an object of the present invention is to provide a hexanuclear copper complex polymer which can be used as a molecular magnetic material and a method for preparing the same.

In order to achieve the purpose, the invention adopts the following technical scheme:

the invention provides a six-core copper coordination polymer, which has a molecular formula as follows: { [ Cu ]₆(H₂L)₄(4,4'-bpy)₆(H₂O)₂]·16H₂O}_nIn which H is₂L is H₅De-triprotic form of L, H₅L represents 6- (3',4' -dicarboxyphenoxy) -2,3, 5-benzenetricarboxylic acid; 4,4'-bpy represents 4,4' -bipyridine. Crystallographic parameters of the polymer: triclinic, P-1 space group,

α＝108.546(4)°，β＝91.177(5)°，γ＝106.531(5)°，

and Z is 2. The copper ions in the polymer respectively adopt a penta-coordination mode and a hexa-coordination mode, wherein Cu1 is in a hexa-coordination mode, and Cu2 and Cu3 are in a penta-coordination mode. Cu1 from two H₅3 carboxyl O atoms in L, two N atoms in two 4,4' -bipyridyl and one water molecule are coordinated; both Cu2 and Cu3 are associated with H from three₅The 3 carboxyl O atoms in L are coordinated to the two N atoms in the two 4,4' -bipyridines. The complex is a three-dimensional network structure. The structural formula is (wave line in the formula represents polymerization connection):

a Cu-N bond length in the range of

A Cu-O bond length in the range of

The crystalline sample of the polymer was uniformly stable as confirmed by X-ray powder diffraction. The experimental data of the variable temperature magnetic susceptibility under the action of the external magnetic field of 1000Oe are used for obtaining that the ferromagnetic interaction exists between copper ions in the polymer and the X is over 100K_m ^-1Fitting the experimental values of-T to obtain θ of 37.42K.

The invention provides a preparation method of the six-core copper coordination polymer, which comprises the following steps:

(1) adding Cu (NO)₃)₂·3H₂O, 6- (3',4' -dicarboxyphenoxy) -2,3, 5-benzenetricarboxylic acid (H)₅L) and 4,4 '-bipyridine (4,4' -bpy) ligand were added to 10mL of distilled water to prepare a mixed system, and the above was mixedThe combined body is arranged in a polytetrafluoroethylene tube, and the pH value of the combined body is adjusted to 4-4.5 by using an acid solution;

(2) and (2) placing the polytetrafluoroethylene tube in the step (1) in a stainless steel reaction kettle, sealing, carrying out hydrothermal reaction, naturally cooling, crystallizing to obtain blue blocky crystals, washing with distilled water, drying in vacuum, and collecting to obtain the hexanuclear copper coordination polymer.

Further, Cu (NO) in the step (1)₃)₂·3H₂The molar ratio of O, 6- (3',4' -dicarboxyphenoxy) -2,3, 5-benzene tricarboxylic acid and 4,4' -bipyridyl is 1-1.5: 1: 1 to 1.5.

The acid solution in the step 1 is HNO with the concentration of 1mol/L₃And (3) solution.

The temperature of the hydrothermal reaction in the step 2 is 120 ℃, and the time of the hydrothermal reaction is 72 h.

The invention provides an application of a six-core copper coordination polymer as a molecular magnetic material.

Compared with the prior art, the invention has the following advantages:

compared with the traditional metal oxide or alloy magnetic material, the complex molecular magnetic material has the characteristics of small volume, light specific gravity, various structures, easy composite processing and forming and the like, and is very suitable to be used as a novel aerospace material and an information storage material. The six-core copper coordination polymer is obtained under hydrothermal conditions, has simple synthesis method and good economic benefit, shows ferromagnetic interaction, can be used as a molecular magnetic material, and has potential application prospect in the electronic information industry.

Drawings

FIG. 1 shows { [ Cu ] of the present invention₆(H₂L)₄(4,4'-bpy)₆(H₂O)₂]·16H₂O}_nCrystal structure diagram (hydrogen atoms and free solvent molecules are omitted for clarity of the drawing) of (a) in which the symmetrical operation codes: a is 1-x, -1-y, 1-z; b-1-x, -y, -z; x, -1+ y,1+ z; d ═ 1+ x, y, z; e ═ 2-x, -1-y, 1-z; f is 1+ x, y, z; g ═ x, -y, -z.

FIG. 2 is an X-ray powder diffraction pattern (experimental and simulated) at 298K for a hexanuclear copper coordination polymer of the present invention.

FIG. 3 is a thermogram of the hexanuclear copper coordination polymer of the present invention at 25 to 800 ℃.

FIG. 4 is a magnetic property curve diagram of the inventive six-core copper coordination polymer under the action of 1000Oe external magnetic field.

Detailed Description

The technical solution in the embodiments of the present invention will be specifically and specifically described below with reference to the embodiments of the present invention and the accompanying drawings.

Example 1

Preparation of a hexanuclear copper coordination polymer:

0.15mmol of Cu (NO)₃)₂·3H₂O，0.10mmol H₅L, and 0.10mmol of 4,4' -bpy were mixed and added to 10mL of distilled water with 1mol/L HNO₃And adjusting the pH value of the mixed system to 4-4.5, placing the mixed system in a 25ml polytetrafluoroethylene tube, and sealing the polytetrafluoroethylene tube in a stainless steel reaction kettle. Keeping the temperature at 120 ℃ for 72h, cooling at room temperature to obtain blue blocky crystals, washing with distilled water, drying in vacuum, and collecting to obtain the hexanuclear copper coordination polymer with the yield of 45%.

Example 2

Structural determination of the hexanuclear copper coordination polymer:

the structure measurement adopts X-ray diffraction, Mo-K alpha rays are monochromatized by a Bruker Smart ApexII detector through a graphite monochromator, the scanning mode omega is adopted, and the temperature of collected data is 298K. The raw data are reduced by SAINT program, then SADABS is used for absorption correction, and the crystal structure is solved by SHELXL-97 direct method. Using full matrix least squares F²All non-hydrogen atoms are anisotropically refined. Finally, the C atoms on the ligands are hydrogenated using theoretical hydrogenation. The hydrogen atoms of the solvent and free water molecules are given by the difference Fourier synthesis. The detailed crystal data are shown in table 1. The crystal structure is shown in figure 1.

TABLE 1 crystallographic data for the complexes

Example 3

Powder diffraction of the hexanuclear copper coordination polymer:

x-ray powder diffraction data were collected using Mo-Ka radiation on a Bruker D8X-ray diffractometer at a scan rate of 5 deg./min and a 2 theta scan range of 5-50 deg.. The results show that the experimental diffraction pattern is consistent with the single crystal simulation pattern, and the phase of the crystal sample is uniform, which is shown in figure 2.

Example 4

Thermogravimetric analysis of a hexanuclear copper coordination polymer:

thermogravimetric analysis was carried out using a Dupont thermal analyzer at a temperature range of 25-800 c under nitrogen atmosphere at a temperature rise rate of 10 c/min. As shown in FIG. 3, it can be seen that the complex lost 16 crystal waters in the range of 25 to 260 ℃ (theoretical and experimental values of 9.02% and 8.22%, respectively), and the temperature was higher than 260 ℃, and the main structure of the complex began to decompose and collapse. Indicating that the coordination polymer can exist stably at 260 ℃.

Example 5

Magnetic properties of the hexanuclear copper coordination polymer:

under the action of an external field of 1000Oe, the curve of the change of the effective magnetic moment of the polymer along with the temperature (2-300K) is shown in figure 4, and it can be seen from the figure that the effective magnetic moment is 3.81 Bohr magnetons at room temperature, the effective magnetic moment gradually increases along with the reduction of the temperature, and the maximum value of the effective magnetic moment is 4.51 Bohr magnetons at 20K; then, the effective magnetic moment is rapidly reduced along with the reduction of the temperature, and the effective magnetic moment is reduced to 3.99 Bohr magnetons at 2K. In addition, Curie-Weiss's law is utilized to measure chi over 100K_m ^-1Fitting is carried out to obtain a value of theta of 37.42K (figure 4), and positive values of theta indicate that ferromagnetic interaction exists between copper ions and the copper ions can be used as a molecular magnetic material.

The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments, and it will be apparent to those skilled in the art that several modifications and improvements can be made without departing from the principle of the present invention, and all of them are included in the protection scope of the present invention.

Furthermore, it should be understood that although the present description refers to embodiments, not every embodiment may contain only a single embodiment, and such description is for clarity only, and those skilled in the art should integrate the description, and the embodiments may be combined as appropriate to form other embodiments understood by those skilled in the art.

Claims

1. A six-core copper coordination polymer is characterized in that the molecular formula is as follows: { [ Cu ]₆(H₂L)₄(4,4'-bpy)₆(H₂O)₂]·16H₂O}_nIn which H is₂L is H₅De-triprotic form of L, H₅L represents 6- (3',4' -dicarboxyphenoxy) -2,3, 5-benzenetricarboxylic acid, 4,4'-bpy represents 4,4' -bipyridine; the crystal belongs to a triclinic system, P-1 space group, unit cell parameters:

α is 108.546(4) °, β is 91.177(5) °, and γ is 106.531(5) °; the structural formula is as follows:

2. a method of preparing the hexanuclear copper coordination polymer of claim 1, comprising the steps of:

step 1, adding Cu (NO)₃)₂·3H₂Adding O, 6- (3',4' -dicarboxyphenoxy) -2,3, 5-benzene tricarboxylic acid and 4,4' -bipyridine into 10mL of distilled water to form a mixed system, adjusting the pH of the mixed system to 4-4.5 by using an acid solution, and placing the mixed system in a polytetrafluoroethylene tube;

and 2, placing the polytetrafluoroethylene tube in a reaction kettle, sealing, carrying out hydrothermal reaction, naturally cooling, crystallizing to obtain blue blocky crystals, washing with distilled water, drying in vacuum, and collecting to obtain the hexanuclear copper coordination polymer.

3. The method for preparing a hexanuclear copper coordination polymer as claimed in claim 2, wherein: cu (NO) in said step 1₃)₂·3H₂The molar ratio of O, 6- (3',4' -dicarboxyphenoxy) -2,3, 5-benzene tricarboxylic acid and 4,4' -bipyridyl is 1-1.5: 1: 1 to 1.5.

4. The method for preparing a hexanuclear copper coordination polymer as claimed in claim 2, wherein: the acid solution in the step 1 is HNO with the concentration of 1mol/L₃And (3) solution.

5. The method for preparing a hexanuclear copper coordination polymer as claimed in claim 2, wherein: the temperature of the hydrothermal reaction in the step 2 is 120 ℃, and the time of the hydrothermal reaction is 72 h.

6. Use of the hexanuclear copper coordination polymer of claim 1 as a molecular magnetic material.