Cd (II) coordination polymer with two-dimensional supramolecular structure and preparation method thereof
阅读说明：本技术 一种具有二维超分子结构的Cd(II)配位聚合物及其制备方法 (Cd (II) coordination polymer with two-dimensional supramolecular structure and preparation method thereof ) 是由 钟开龙 吴晓琼 许锡婷 于 2020-12-10 设计创作，主要内容包括：本发明涉及一种具有二维超分子结构的Cd(II)配位聚合物及其制备。配位聚合物是由金属Cd 离子和两种有机分子配体配位构筑而成,本发明所述Cd(II)混配配位聚合物的制备方法简单,操作方便,产率高,重现性好。本发明所述Cd(II)配位聚合物稳定性好,具有荧光性质,有望用作荧光材料。(The invention relates to a Cd (II) coordination polymer with a two-dimensional supramolecular structure and a preparation method thereof. The coordination polymer is constructed by coordination of metal Cd ions and two organic molecular ligands, and the preparation method of the Cd (II) mixed coordination polymer is simple, convenient to operate, high in yield and good in reproducibility. The Cd (II) coordination polymer has good stability and fluorescent property, and is expected to be used as a fluorescent material.)
1. A Cd (II) coordination polymer with a two-dimensional supermolecular structure, the chemical formula is C18H14N4O9Cd, the manganese three-dimensional coordination polymer belongs to a monoclinic system, C2/C space group, and the unit cell parameter isa＝22.390(4)Å，b＝6.2758(13)Å，c＝14.962(3)Å，α＝90 °，β＝104.15(3) °，γ＝90°，V＝2038.6(7)Å3；
The central atom of Cd in the Cd (II) coordination polymer is positioned on a double-fold symmetry axis, and is coordinated with 4 carboxyl O atoms from two 3-nitrobenzoate, 2N atoms on two different pyrazine ligands and one water molecule O by adopting a heptadentate deformed pentagonal bipyramid coordination configuration.
2. The method for preparing Cd (II) coordination polymers with two-dimensional supramolecular structures according to claim 1, wherein: adding 3-nitrobenzoic acid, pyrazozine and cadmium chloride into a mixed solution of ethanol and distilled water, fully stirring and filtering, then placing the filtrate into a high-pressure reaction kettle, carrying out heating reaction under the solvothermal condition, and slowly cooling to obtain the Cd (II) coordination polymer.
3. Method for the preparation of cd (ii) coordination polymers with two-dimensional supramolecular structures according to claim 2, characterized in that: the molar ratio of the 3-nitrobenzoic acid to the pyrazine to the cadmium chloride is 2:1: 1.
Technical Field
The invention relates to the field of coordination polymer materials, in particular to a Cd (II) coordination polymer with a two-dimensional supramolecular structure and a preparation method thereof.
Background
In 1989, the first article on Coordination Polymers (CPs) was published by professor Richard Robson in australia, and has received much attention from scientists because of its attractive topology and its potential application in the fields of material science such as catalysis, adsorption, molecular recognition, molecular luminescence, etc., as a novel molecular functional material. Over the past thirty years, scientists have synthesized and studied a large number of coordination polymers with novel topologies for their performance in applications.
The organic nitrogen heterocyclic ligand, such as pyrazine and derivatives thereof, has good complexing and coordination properties. The organic carboxylic acid ligand has rich coordination mode, especially the aromatic carboxylic acid ligand has rigidity of the skeletonThe formed complex skeleton structure can effectively prevent the generation of a through structure, and lays a foundation for the construction of porous materials. Based on design controllability of a target structure, people often combine the respective advantages of the two types of ligands to construct a new functional mixed coordination polymer. The fluorescent property being d10The development of the applications of coordination polymers of metal ions in luminescent devices, chemical sensors and the like is an active research field of fluorescent CPs materials.
Prior to the work of this patent application, there was no discussion of 3-nitrobenzoic acid, pyrazine and CdCl2In EtOH/H2The patent literature and scientific article report on the aspect of self-assembly to form coordination polymer in the mixed solvent of O.
Disclosure of Invention
The invention aims to provide a Cd (II) coordination polymer with a two-dimensional supramolecular structure.
Another object of the present invention is to provide a process for producing the above Cd (II) coordination polymer.
The technical problem to be solved by the invention is realized by the following technical scheme:
a Cd (II) coordination polymer with a two-dimensional supermolecular structure, the chemical formula is C18H14N4O9Cd, the manganese three-dimensional coordination polymer belongs to a monoclinic system, C2/C space group, and the unit cell parameter isa＝22.390(4)Å，b＝6.2758(13)Å，c＝14.962(3)Å，α＝90 °，β＝104.15(3) °，γ＝90°，V＝2038.6(7)Å3。
Furthermore, the central atom of Cd is positioned on a double-fold symmetry axis, and adopts a heptadentate deformed pentagon bipyramid coordination configuration to coordinate with 4 carboxyl O atoms from two 3-nitrobenzoate, 2N atoms on two different pyrazine ligands and one water molecule O; the bond lengths of Cd-O bonds are 2.277(4) A, 2.381(2) and 2.418(3) A, respectively, and the bond length of Cd-N bonds is 2.358(3) A.
Furthermore, each bridging pyrazine ligand is connected with two Cd centers to form a one-dimensional chain structure extending along the [ 010 ] direction.
Furthermore, the one-dimensional chain structure forms a two-dimensional supramolecular network structure through typical O-H … O hydrogen bond interaction.
A preparation method of Cd (II) coordination polymer with a two-dimensional supramolecular structure comprises the following steps: adding 3-nitrobenzoic acid, pyrazozine and cadmium chloride into a mixed solution of ethanol and distilled water, fully stirring and filtering, then placing the filtrate into a high-pressure reaction kettle, carrying out heating reaction under the solvothermal condition, and slowly cooling to obtain the Cd (II) coordination polymer.
Further, the heating temperature is 120-160 ℃.
Further, the heating reaction time is 48-96 hours.
Further, the temperature is reduced to room temperature at the rate of 2-10 ℃/h.
Further, the volume ratio of the mixed solution ethanol to the distilled water is 1: 1.
Further, the molar ratio of the 3-nitrobenzoic acid to the pyrazine to the cadmium chloride is 1.8-2.2: 0.9-1.1.
Further, the molar ratio of the 3-nitrobenzoic acid to the pyrazine to the cadmium chloride is preferably 2:1: 1.
The invention has the following beneficial effects:
the Cd (II) coordination polymer with a two-dimensional supramolecular structure is synthesized for the first time under the solvothermal condition, as shown in figure 4, the Cd (II) coordination polymer has stable fluorescence and can be used as a potential fluorescent material, as shown in figure 5, the Cd (II) coordination polymer starts to decompose at about 230 ℃, and can be stable for months when placed at room temperature, so that the stability is good, and a foundation is provided for being used as a potential fluorescent material; the preparation method of the Cd (II) mixed coordination polymer has the advantages of simple and convenient operation and good reproducibility.
Drawings
FIG. 1 is a coordination environment diagram of a cadmium coordination polymer metal center Cd (II).
FIG. 2 is a one-dimensional chain structure diagram of a cadmium coordination polymer.
FIG. 3 is a two-dimensional supramolecular structural diagram of a cadmium coordination polymer.
FIG. 4 is a solid state fluorescence spectrum of a cadmium coordination polymer.
FIG. 5 is a thermogravimetric analysis of a cadmium coordination polymer.
Detailed Description
The present invention will be described in detail with reference to examples, which are only preferred embodiments of the present invention and are not intended to limit the present invention.
Example 1:
dissolving 0.1mmol of cadmium chloride, 0.1mmol of pyrazine and 0.2mmol of 3-nitrobenzoic acid in 20mL of ethanol/distilled water: (V:VAnd =1:1), stirring at normal temperature for 20min, filtering, transferring the filtrate to a stainless steel reaction kettle with a polytetrafluoroethylene lining, sealing the stainless steel reaction kettle, putting the stainless steel reaction kettle into an oven, reacting at 140 ℃ for 72h, and then cooling to room temperature at 2 ℃/h to obtain the cadmium coordination polymer, wherein the yield is 58.6% (based on Cd).
Then carrying out structural characterization on the cadmium coordination polymer
The X-ray diffraction data of the crystal is measured by a Bruker Smart Apex CCD single crystal diffractometer. Mo Ka rays monochromatized with graphite at 273K ((R))λ= 0.071073nm) as a radiation source, and diffraction data is collected. The scan mode is phi-omega scan, and Lp factor correction and empirical absorption correction are performed, and the SADABS program is used for absorption correction. The position coordinates of metal atoms and non-hydrogen atoms are determined by a direct method, the coordinates of all the non-hydrogen atoms and anisotropic thermal parameters thereof are corrected by a full matrix least square method, the hydrogen atoms except water molecules are determined by theoretical hydrogenation and are isotropically refined, and the hydrogen atoms on the water molecules are directly found out from a difference Fourier map. The crystallographic parameters are shown in Table 1, and the structures are shown in figure 1, figure 2 and figure 3.
TABLE 1 Main crystallographic data of manganese three-dimensional coordination polymers prepared
Empirical formula
C18H14N4O9Cd
Formular weight
542.73
Crystal size / mm
0.32×0.40×0.20
Crystal system
Monolinic
Space group
C2/c
a / Å
22.390(4)
b / Å
6.2758(13)
c/ Å
14.962(3)
α / (º)
90
β / (º)
104.15(3)
γ / (º)
90
V / Å 3
2038.6(7)
Z
4
D c / (g·cm-3)
1.768
λ / nm
0.071073
Temperature / K
273.15
θ range / (º)
3.38～27.46
Collected reflections
8628
Unique reflections
1795
Observed reflection
1723
R
int
0.0463
F(000)
1080
μ / mm-1
1.131
R
1
0.0317
wR
2
0.0787
The coordination environment of a metal center Cd atom is shown in figure 1, and it can be seen from the figure that the metal center Cd atom and a water molecule O atom are positioned on a double-fold symmetry axis, and the metal center Cd atom adopts a hepta-coordination deformed pentagonal bipyramid coordination configuration and coordinates with 4 carboxyl O atoms from two 3-nitrobenzoate, 2N atoms on two non-pyrazine ligands and one water molecule O; the bond lengths of Cd-O bonds are 2.277(4) A, 2.381(2) and 2.418(3) A, respectively, and the bond length of Cd-N bonds is 2.358(3) A. Each bridging pyrazine ligand is connected with two Cd centers to form a one-dimensional chain structure extending along the [ 010 ] direction, as shown in FIG. 2. The one-dimensional chain structure is further subjected to typical O-H … O hydrogen bond interaction to form a two-dimensional supramolecular network structure, as shown in FIG. 3.
The cadmium coordination polymer prepared in this example was subjected to solid-state fluorescence analysis, and the spectrum thereof is shown in fig. 4. The figure shows that: the cadmium coordination polymer has stable fluorescence and can be used as a potential fluorescent material.
Thermogravimetric analysis was performed on the cadmium coordination polymer prepared in this example, and the spectrum thereof is shown in fig. 5. The figure shows that: the main skeleton structure of the cadmium coordination polymer can be stabilized to 230 ℃, and the cadmium coordination polymer can be stabilized for months when being placed at room temperature, so that the cadmium coordination polymer has good stability.
Example 2:
dissolving 0.1mmol of cadmium chloride, 0.1mmol of pyrazine and 0.2mmol of 3-nitrobenzoic acid in 20mL of ethanol/distilled water: (V:VAnd =1:1), stirring at normal temperature for 20min, filtering, transferring the filtrate to a stainless steel reaction kettle with a polytetrafluoroethylene lining, sealing the stainless steel reaction kettle, putting the stainless steel reaction kettle into an oven, reacting at 120 ℃ for 48h, and then cooling to room temperature at 5 ℃/h to obtain the cadmium coordination polymer, wherein the yield is 55.8% (based on Cd).
Example 3:
dissolving 0.11mmol of cadmium chloride, 0.09mmol of pyrazine and 0.18mmol of 3-nitrobenzoic acid in 20mL of ethanol/distilled water: (V:VAnd =1:1), stirring at normal temperature for 20min, filtering, transferring the filtrate to a stainless steel reaction kettle with a polytetrafluoroethylene lining, sealing the stainless steel reaction kettle, putting the stainless steel reaction kettle into an oven, reacting at 130 ℃ for 60h, and then cooling to room temperature at 2 ℃/h to obtain the cadmium coordination polymer, wherein the yield is 49.6% (based on Cd).
Example 4:
dissolving 0.09mmol of cadmium chloride, 0.09mmol of pyrazine and 0.22mmol of 3-nitrobenzoic acid in 20mL of ethanol/distilled water: (V:VAnd =1:1), stirring at normal temperature for 20min, filtering, transferring the filtrate to a stainless steel reaction kettle with a polytetrafluoroethylene lining, sealing the stainless steel reaction kettle, putting the stainless steel reaction kettle into an oven, reacting at 140 ℃ for 96h, and then cooling to room temperature at 5 ℃/h to obtain the cadmium coordination polymer, wherein the yield is 57.9% (based on Cd).
Example 5:
dissolving 0.11mmol of cadmium chloride, 0.11mmol of pyrazine and 0.2mmol of 3-nitrobenzoic acid in 20mL of ethanol/distilled water: (V:VIn the ratio of 1:1), stirring for 20min at normal temperature, filtering, and mixingTransferring the filtrate to a stainless steel reaction kettle with a polytetrafluoroethylene lining, sealing the stainless steel reaction kettle, putting the stainless steel reaction kettle into an oven, reacting for 72 hours at 160 ℃, and then cooling to room temperature at 10 ℃/hour to obtain the cadmium coordination polymer with the yield of 53.6% (based on Cd).
The above-mentioned embodiments only express the embodiments of the present invention, and the description is more specific and detailed, but not understood as the limitation of the patent scope of the present invention, but all the technical solutions obtained by using the equivalent substitution or the equivalent transformation should fall within the protection scope of the present invention.