CN105884805B - A kind of Cd (II) mixture coordination polymer and preparation method thereof - Google Patents

Abstract

The invention relates to a Cd(II) mixed coordination polymer and a preparation method thereof. The mixed coordination polymer is formed by the coordination of metal Cd ions and two kinds of organic molecular ligands. The Cd(II) mixed coordination polymer of the present invention has good stability and fluorescent properties, and is expected to be used as a fluorescent Material. The preparation method of the Cd(II) mixed coordination polymer of the invention is simple, convenient to operate, high in yield and good in reproducibility.

Description

A kind of Cd(II) mixed coordination polymer and its preparation method

technical field

The invention relates to the technical field of coordination polymers, in particular to a cadmium (II) mixed coordination polymer and a preparation method thereof.

Background technique

Coordination polymers are metal-organic framework crystal materials (Metal-Organic Frameworks, MOFs) with a periodic network structure, which are self-assembled through the interaction force between organic ligands and metal ions (or metal clusters). ). Compared with traditional inorganic materials and organic supramolecular materials, this type of compound can design and synthesize materials with rich and diverse skeleton structures and excellent physical and chemical properties due to the wider selection of metal ions and organic ligands. . Because such compounds not only have aesthetic value but also have great potential in many fields such as gas storage, separation, gas storage, separation, trapping, selective catalysis, chiral resolution, drug delivery, light, electricity, magnetism and molecular recognition. potential practical application value.

The ligands of nitrogen-containing heterocyclic rings include pyridine, imidazole, triazole, tetrazole, pyrazole, pyrazine and their various derivatives, etc. Due to the strong coordination ability of the nitrogen atom, such ligands have been widely used to construct new Functional coordination polymers, but only nitrogen-heterocyclic ligands have a relatively single coordination mode.

The carboxyl oxygen atoms of organic carboxylic acid ligands have rich coordination modes, and can coordinate with transition, rare earth metal ions, metal clusters, etc. to form a complex skeleton structure. This type of complex has high thermal stability and tailorability, etc. features. In particular, aromatic carboxylic acid ligands can effectively prevent the generation of through structures due to the rigidity of their own skeletons, laying a foundation for the construction of porous materials.

Based on the controllability of the design of the target structure, the common strategy of chemists is to make full use of the respective advantages of the two types of ligands to construct mixed coordination polymers.

For complexes containing d ¹⁰ metal ions, the fluorescence property is an important property of such complex polymers. At present, the research work on fluorescent MOFs materials is mainly focused on: creating MOFs materials with adjustable fluorescence properties and developing their applications in light-emitting devices; using fluorescent MOFs materials as probes to detect environments and studying their applications in chemical sensors ; Create multifunctional MOFs materials that combine fluorescence, magnetism and biocompatibility, and develop their applications in biomedicine, such as cell biological tissue imaging and drug delivery monitoring and treatment.

Contents of the invention

The technical problem to be solved by the present invention is to provide a cadmium (II) mixed coordination polymer coordination polymer.

In order to solve the above-mentioned technical problems, the technical scheme provided by the present invention is: a coordination polymer with formula I as a skeleton unit,

Formula I:

Among them, Cd(II) is a hexacoordinated, distorted octahedral coordination configuration.

Preferably, the Cd(II) mixed coordination polymer belongs to the orthorhombic crystal system, the space group Pbcn, and the unit cell parameters are a=13.201(3)nm, b=10.104(2)nm, c=19.943(4)nm )nm, α=β=γ=90.00°, V=2660.1(9)nm ³ .

In the present invention, the chemical formula of the Cd(II) mixed coordination polymer is Cd(C ₁₀ H ₈ N ₂ ) ₂ (C ₁₀ H ₄ O ₈ ), wherein C ₁₀ H ₈ N ₂ is 2,2' - bipyridine, its structural formula is as follows:

C ₁₀ H ₄ O ₈ is pyromellitic acid dianion, and its structural formula is as follows:

The basic building block of Cd(II) mixed coordination polymers is a one-dimensional structure, in which Cd(II) is hexacoordinated, and four Ns from two different 2,2'-bipyridyl ligands respectively The atom is coordinated with two O atoms from two pyromellitic ions, and the cadmium central ion adopts a distorted octahedral coordination configuration. The pyromellitic ions act as bridges, linking the adjacent metal Cd ion centers to form a one-dimensional chain structure, and the adjacent one-dimensional chains form intermolecular H through the carboxylic acid groups on pyromellitic acid. The —O···H hydrogen bond is further constructed into a two-dimensional layered structure.

Another technical problem to be solved by the present invention is to provide a method for preparing the above-mentioned Cd(II) mixed coordination polymer.

In order to solve the above technical problems, the technical solution provided by the present invention is: the preparation method of Cd(II) mixed coordination polymer, comprising the following steps: adding cadmium salt, 2,2'-bipyridine and pyromellitic acid into ethanol and distilled water, adjust the system to be acidic after stirring, then place it in a high-pressure reactor for thermal reaction with water (solvent), cool and filter after the reaction to obtain the Cd(II) mixed coordination polymer.

Preferably, the cadmium salt is one or a mixture of cadmium chloride, cadmium nitrate, cadmium perchlorate, cadmium acetate, and cadmium sulfate.

Preferably, the ratio of the moles of cadmium in the cadmium salt to the moles of 2,2'-bipyridine and pyromellitic acid is 1:1.8-3:1-2; preferably, the moles of cadmium in the cadmium salt and The molar ratio of 2,2'-bipyridine and pyromellitic acid is 1:2.2-2.6:1.2-1.8; The molar ratio of formic acid is 1 : 2.5 : 1.5

Preferably, cadmium salt, 2,2'-bipyridine and pyromellitic acid are added to a mixed solution of ethanol and distilled water, and the pH value of the system is adjusted to 2-6 after stirring; preferably, cadmium salt is mixed with 2,2 '-bipyridine and pyromellitic acid are added to the mixed solution of ethanol and distilled water, and the pH value of the system is adjusted to 3-5 after stirring; preferably, cadmium salt, 2,2'-bipyridine and pyromellitic acid are added In the mixed solution of ethanol and distilled water, adjust the pH value of the system to 4 after stirring.

Preferably, the temperature of the water (solvent) thermal reaction is 120-160°C, and the time of the water (solvent) thermal reaction is 24-72h; preferably, the temperature of the water (solvent) thermal reaction is 130-150°C , the time of hydrothermal reaction is 36-60h; Preferably, the temperature of described water (solvent) thermal reaction is 140 ℃, the time of water (solvent) thermal reaction is 48h.

Preferably, the volume ratio of ethanol and distilled water in the mixed solution of ethanol and distilled water is 1: 4; Preferably, the volume ratio of ethanol and distilled water in the mixed solution of ethanol and distilled water is 2: 3; Preferably, the ethanol The volume ratio of ethanol and distilled water in the mixed solution of distilled water is 1: 1.

Beneficial effects of the present invention: In the present invention, as shown in Figure 4, the Cd(II) mixed coordination polymer has stable fluorescence and can be used as a potential fluorescent material, as shown in Figure 5, the Cd(II) (II) The mixed coordination polymer begins to decompose at about 185°C, and it can be stable for several months at room temperature, so its stability is good, which provides a basis for potential fluorescent materials; the Cd of the present invention (II) The preparation method of the mixed coordination polymer is simple and convenient to operate. By adjusting various parameters in the preparation method, the preparation method of the Cd(II) mixed coordination polymer has high yield and reproducibility it is good.

Description of drawings

The coordination environment figure of Cd (II) in the Cd (II) coordination polymer of Fig. 1 of the present invention;

Fig. 2 The one-dimensional chain structure diagram in the Cd(II) coordination polymer of the present invention;

Fig. 3 is a two-dimensional layered structure diagram formed in the Cd(II) coordination polymer of the present invention;

Fig. 4 The solid-state fluorescence spectrum of Cd (II) coordination polymer, 2,2'-bipyridine and pyromellitic acid according to the present invention;

Fig. 5 The thermogravimetric spectrum of Cd (II) position polymer of the present invention;

Fig. 6 The infrared spectrum of the Cd(II) position polymer of the present invention.

Detailed ways

Example 1:

Dissolve 0.1mmol cadmium nitrate, 0.25mmol 2,2'-bipyridine and 0.15mmol pyromellitic acid in 20mL ethanol/distilled water ( V : V =1:1), stir at room temperature for 15min and use 0.2mol/L hydrogen Sodium oxide solution adjusts the pH value of the system to 4, stirs at room temperature for 15 minutes and then filters, transfers the filtrate to a stainless steel reaction kettle lined with polytetrafluoroethylene, seals the stainless steel reaction kettle and puts it in an oven. (Solvent) thermal reaction for 48h, naturally cooled to room temperature, and filtered to obtain a large number of colorless block crystals, the colorless block crystals were washed with distilled water to obtain the Cd (II) coordination polymer, the yield was 63.6% ( Based on Cd).

Example 2:

Dissolve 0.1mmol cadmium sulfate, 0.22mmol 2,2'-bipyridine and 0.15mmol pyromellitic acid in 20mL ethanol/distilled water (V:V=1:4), stir at room temperature for 15min and use 0.2mol/L hydrogen Sodium oxide solution adjusts the pH of the system to 5, stirs at room temperature for 15 minutes and then filters, transfers the filtrate to a stainless steel reaction kettle lined with polytetrafluoroethylene, seals the stainless steel reaction kettle and puts it in an oven. (Solvent) heat reaction for 24h, naturally cooled to room temperature, obtained a large number of colorless block crystals after filtration, the colorless block crystals were washed with distilled water to obtain the Cd (II) coordination polymer, the yield was 62.8% ( Based on Cd).

Example 3:

Dissolve 0.1mmol cadmium acetate, 0.2mmol 2,2'-bipyridine and 0.15mmol pyromellitic acid in 20mL ethanol/distilled water ( V : V =2:3), stir at room temperature for 15min and use 0.2mol/L hydrogen Sodium oxide solution adjusts the pH value of the system to 4, stirs at room temperature for 15 minutes and then filters, transfers the filtrate to a stainless steel reaction kettle lined with polytetrafluoroethylene, seals the stainless steel reaction kettle and puts it in an oven. (Solvent) heat reaction for 72h, naturally cooled to room temperature, obtained a large number of colorless block crystals after filtration, the colorless block crystals were washed with distilled water to obtain the Cd (II) coordination polymer, the yield was 61.5% ( Based on Cd).

Example 4:

Dissolve 0.1mmol cadmium chloride, 0.22mmol 2,2'-bipyridine and 0.12mmol pyromellitic acid in 20mL ethanol/distilled water ( V : V =1:1), stir at room temperature for 15min and use 0.2mol/L Sodium hydroxide solution adjusts the pH of the system to 3, stirs at room temperature for 15 minutes and then filters, transfers the filtrate to a stainless steel reaction kettle lined with polytetrafluoroethylene, seals the stainless steel reaction kettle and puts it in an oven, at 130°C Water (solvent) thermal reaction for 36h, naturally cooled to room temperature, filtered to obtain a large number of colorless block crystals, the colorless block crystals were washed with distilled water to obtain the Cd (II) coordination polymer, the yield was 62.1% (based on Cd).

Example 5:

Dissolve 0.1mmol cadmium perchlorate, 0.26mmol 2,2'-bipyridine and 0.13mmol pyromellitic acid in 20mL ethanol/distilled water ( V : V =1:1), stir at room temperature for 15min and use 0.2mol/L Sodium hydroxide solution to adjust the pH value of the system to 3, filter after stirring at room temperature for 15min, transfer the filtrate to a stainless steel reaction kettle lined with polytetrafluoroethylene, seal the stainless steel reaction kettle and put it into an oven, at 140 Heat reaction with water (solvent) at ℃ for 24 hours, cool naturally to room temperature, obtain a large number of colorless blocky crystals after filtration, wash the colorless blocky crystals with distilled water to obtain the Cd(II) coordination polymer, and the yield is 62.6 % (based on Cd).

Embodiment 6:

Dissolve 0.1mmol cadmium sulfate, 0.25mmol 2,2'-bipyridine and 0.15mmol pyromellitic acid in 20mL ethanol/distilled water ( V : V =1:1), stir at room temperature for 15min and use 0.2mol/L hydrogen Sodium oxide solution adjusts the pH value of the system to 4, stirs at room temperature for 15 minutes and then filters, transfers the filtrate to a stainless steel reaction kettle lined with polytetrafluoroethylene, seals the stainless steel reaction kettle and puts it in an oven. (Solvent) thermal reaction for 48h, naturally cooled to room temperature, and filtered to obtain a large number of colorless block crystals, the colorless block crystals were washed with distilled water to obtain the Cd (II) coordination polymer, the yield was 63.5% ( Based on Cd).

Embodiment 7:

Dissolve 0.1mmol cadmium sulfate, 0.25mmol 2,2'-bipyridine and 0.12mmol pyromellitic acid in 20mL ethanol/distilled water ( V : V =1:1), stir at room temperature for 15min and use 0.2mol/L hydrogen Sodium oxide solution adjusts the pH value of the system to 4, stirs at room temperature for 15 minutes and then filters, transfers the filtrate to a stainless steel reaction kettle lined with polytetrafluoroethylene, seals the stainless steel reaction kettle and puts it in an oven. (Solvent) heat reaction for 48h, naturally cooled to room temperature, obtained a large number of colorless block crystals after filtration, the colorless block crystals were washed with distilled water to obtain the Cd (II) coordination polymer, the yield was 62.5% ( Based on Cd).

Embodiment 8:

Dissolve 0.1mmol cadmium sulfate, 0.25mmol 2,2'-bipyridine and 0.15mmol pyromellitic acid in 20mL ethanol/distilled water ( V : V =1:4), stir at room temperature for 15min and use 0.2mol/L hydrogen Sodium oxide solution adjusts the pH value of the system to 4, stirs at room temperature for 15 minutes and then filters, transfers the filtrate to a stainless steel reaction kettle lined with polytetrafluoroethylene, seals the stainless steel reaction kettle and puts it in an oven. (Solvent) thermal reaction for 48h, naturally cooled to room temperature, and filtered to obtain a large number of colorless block crystals, the colorless block crystals were washed with distilled water to obtain the Cd (II) coordination polymer, the yield was 62.8% ( Based on Cd).

Embodiment 9:

Dissolve 0.1mmol cadmium sulfate, 0.25mmol 2,2'-bipyridine and 0.12mmol pyromellitic acid in 20mL ethanol/distilled water ( V : V =1:1), stir at room temperature for 15min and use 0.2mol/L hydrogen Sodium oxide solution adjusted the pH value of the system to 4, stirred at room temperature for 15 minutes and then filtered, transferred the filtrate to a stainless steel reaction kettle lined with polytetrafluoroethylene, sealed the stainless steel reaction kettle and put it in an oven. (solvent) heat reaction for 48h, naturally cooled to room temperature, obtained a large amount of colorless block crystals after filtration, and obtained the Cd (II) coordination polymer after the colorless block crystals were washed with distilled water, and the yield was 63.3% ( Based on Cd).

The chemical formula of the Cd(II) mixed coordination polymer prepared in Example 1 is C ₃₀ H ₂₀ N ₄ O ₈ Cd, and elemental analysis is carried out to it, the results are as follows: theoretical value (%): C, 53.25; H , 2.96; N, 8.28. Found values (%): C, 53.31; H, 2.91; N, 8.32.

The Cd(II) mixed coordination polymer prepared in Example 1 was taken for infrared spectrum testing, and its spectrum is shown in FIG. 6 .

The crystal structure of the Cd(II) mixed coordination polymer prepared in Example 1 was tested, and the main crystallographic data are shown in Table 1.

Table 1 The main crystal data of the Cd(II) mixed coordination polymer prepared in Example 1

compound 1 Empirical formula C ₃₀ H ₂₀ N ₄ O ₈ Cd Formula weight 676.90 Crystal size / mm 0.30×0.25×0.20 Crystal system Orthorhombic Space group Pbcn a /nm 13.201(3) b /nm 13.201(3) c /nm 19.943(4) α / (°) 90.00 β / (°) 90.00 gamma / (º) 90.00 V / ^nm3 2660.1(9) Z 4 D _c / (g·cm ^-3 ) 1.690 λ /nm 0.071073 Temperature /K 223.15 θ range / (º) 1.54～27.47 Collected reflections 10560 Unique reflections 3027 Observed reflection 2727 R _int 0.0204 F(000) 1360 μ /mm ^-1 0.884 R ₁ 0.0323 wxya ₂ 0.1149

The Cd(II) mixed coordination polymer of the present invention has a chemical formula of Cd(C ₁₀ H ₈ N ₂ ) ₂ (C ₁₀ H ₄ O ₈ ), wherein C ₁₀ H ₈ N ₂ is 2,2' - Bipyridine, C ₁₀ H ₄ O ₈ is a pyromellitic acid dianion. This coordination polymer belongs to the orthorhombic crystal system, the Pbcn space group, and the unit cell parameters are: a=13.201(3)nm, b=10.104(2)nm, c=19.943(4)nm, α=β=γ= 90.00°, V=2660.1(9)nm ³ . The basic building block of the Cd(II) mixed coordination polymer is a one-dimensional structure. The three coordinated N atoms come from two different 2,2'-bipyridine ligands, and the two O atoms come from the carboxylic acid groups on the two pyromellitic ions, as shown in Figure 1 and Figure 2. Show. The pyromellitic ions act as bridges, linking the adjacent metal center Cd ions to form a one-dimensional chain structure, and the adjacent one-dimensional chains form intermolecular H through the carboxylic acid groups on pyromellitic acid. —O···H hydrogen bonds are further constructed into a two-dimensional layered structure, as shown in Figure 3.

The above-described embodiments only express the implementation manner of the present invention, and its description is more specific and detailed, but it should not be interpreted as limiting the scope of the patent of the present invention, as long as the technical solutions obtained in the form of equivalent replacement or equivalent transformation are adopted , should fall within the protection scope of the present invention.

Claims (8)

1. a kind of Cd (II) mixture coordination polymer, chemical formula is Cd (C₁₀H₈N₂)₂(C₁₀H₄O₈), wherein C₁₀H₈N₂It is 2, 2 '-bipyridyls, C₁₀H₄O₈For Pyromellitic Acid root dianion；

It is characterized in that, the coordination polymer belongs to rhombic system, Pbcn space groups, cell parameter is a=13.201 (3) Nm, b=10.104 (2) nm, c=19.943 (4) nm, α=β=γ=90.00 °, V=2660.1 (9) nm³；

The coordination polymer using Formulas I as the coordination polymer of skeleton unit,

Formulas I：

Wherein, Cd (II) be hexa-coordinate, distortion octahedral coordination configuration.

2. the preparation method of Cd (II) mixture coordination polymer according to claim 1, includes the following steps：By cadmium salt, 2, 2 '-bipyridyls and Pyromellitic Acid are added in the mixed solution of ethyl alcohol and distilled water, and after stirring then regulation system is set in acidity Hydro-thermal reaction is carried out in autoclave, cools down after reaction, the Cd (II) coordination polymer is obtained by filtration.

3. the preparation method of Cd (II) mixture coordination polymer according to claim 2, which is characterized in that the cadmium salt is chlorine The mixture of one or more of cadmium, cadmium nitrate, cadmium perchlorate, cadmium acetate, cadmium sulfate.

4. the preparation method of Cd (II) mixture coordination polymer according to claim 2, which is characterized in that cadmium rubs in cadmium salt Your the ratio between number and the molal quantity of 2,2 '-bipyridyls and Pyromellitic Acid are 1: 2.5 : 1.5.

5. the preparation method of Cd (II) mixture coordination polymer according to claim 2, which is characterized in that by cadmium salt and 2, 2 '-bipyridyls and Pyromellitic Acid are added in the mixed solution of ethyl alcohol and distilled water, and the pH value of regulation system is 4 after stirring.

6. the preparation method of Cd (II) mixture coordination polymer according to claim 2, which is characterized in that the ethyl alcohol and steaming Ethyl alcohol and distilled water volume ratio are 1 in the mixed solution of distilled water:1.

7. the preparation method of Cd (II) mixture coordination polymer according to claim 2, which is characterized in that the hydro-thermal reaction Temperature be 140 DEG C, time of water (solvent) thermal response is 48h.

8. the preparation method of Cd (II) mixture coordination polymer according to claim 2, which is characterized in that including following step Suddenly：0.1mmol cadmium nitrates, 0.25mmol 2,2 '-bipyridyls and 0.15mmol Pyromellitic Acids are dissolved in 20mL ethyl alcohol and steaming In distilled water, the volume ratio of the ethyl alcohol and distilled water is 1：It is molten using the sodium hydroxide of 0.2mol/L after 1, stirring at normal temperature 15min The pH value of liquid regulation system is 4, and filtrate is transferred to and is made in the stainless steel cauldron of lining with polytetrafluoroethylene (PTFE), by stainless steel It is put into baking oven after reaction kettle sealing, the hydro-thermal reaction 48h at 140 DEG C, cooled to room temperature obtains the Cd after filtering (II) mixture coordination polymer；

Or by 0.1mmol cadmium sulfates, 0.22mmol2,2 '-bipyridyls and 0.15mmol Pyromellitic Acids be dissolved in 20m ethyl alcohol and In distilled water, the volume ratio of the ethyl alcohol and distilled water is 1：The sodium hydroxide of 0.2mol/L is utilized after 4, stirring at normal temperature 15min The pH value of solution regulation system is 5, is filtered after stirring 15min at room temperature, filtrate is transferred to and makees lining with polytetrafluoroethylene (PTFE) It in stainless steel cauldron, is put into baking oven after stainless steel cauldron is sealed, hydro-thermal reaction for 24 hours, naturally cools at 160 DEG C Room temperature obtains the Cd (II) mixture coordination polymer after filtering；

Or 0.1mmol caddies, 0.22mmol 2,2 '-bipyridyls and 0.12mmol Pyromellitic Acids are dissolved in 20mL ethyl alcohol In distilled water, the volume ratio of the ethyl alcohol and distilled water is 1：The hydroxide of 0.2mol/L is utilized after 1, stirring at normal temperature 15min The pH value of sodium solution regulation system is 3, is filtered after stirring 15min at room temperature, filtrate is transferred to and makees lining with polytetrafluoroethylene (PTFE) Stainless steel cauldron in, be put into baking oven after stainless steel cauldron is sealed, in 130 DEG C of hydro-thermal reaction 36h, naturally cool to Room temperature obtains the Cd (II) mixture coordination polymer after filtering.