CN106893111A - Method for preparing gold @ rare earth coordination polymer nanoparticles - Google Patents

Abstract

The invention discloses a method for preparing gold@rare earth coordination polymer nanoparticles, using CTAB as a protective agent, HAuCl ₄ ·3H ₂ O as a raw material, and using a seed-mediated method to synthesize gold nanoparticles with a particle diameter of about 20nm , the present invention uses a mixed solvothermal method to synthesize the precursor. Since the reaction is in a closed environment, the synthesized precursor is uniform and difficult to agglomerate. The gold@rare earth coordination polymer core-shell structure nanoparticles synthesized by the present invention have an average particle size of 100nm and uniform distribution At present, micro-nano materials with core-shell structure have great application potential in the fields of chemical catalysis, biomedical engineering, optical imaging and drug release, so this product has potential application value in the above fields.

Description

A method for preparing gold@rare earth coordination polymer nanoparticles

technical field

The invention relates to a coordination polymer, in particular to a method for preparing gold@rare earth coordination polymer nanoparticles.

Background technique

Coordination polymers not only have unique and novel structures through rational selection of ligands and metal ions, but also exhibit excellent properties in luminescence, magnetism, gas adsorption and separation, heterogeneous catalysis, drug transport, and chemical sensing. much attention.

The rare earth in the rare earth coordination polymer has more coordination numbers, and the formed coordination polymer has higher thermal stability. As an important branch of the coordination polymer, this type of compound is also a good luminescent material and catalytic material. , chemical sensing materials and magnetic materials.

The core-shell structure is a kind of wrapping of one or several material layers through chemical bonds, intermolecular forces, etc. Due to its special structure, compared with a single element structure, it can better meet the multi-functional and diversified application requirements , and this type of material can effectively prevent the agglomeration of particles by functionalizing the shell, enhance the stability of the wrapped particles, and make the material have special optical, electrical, magnetic, catalytic and other properties.

The synthesis methods of core-shell structure mainly include hydrothermal/solvothermal method, sol-gel method, seed crystal growth method and co-precipitation method, among which hydrothermal/solvothermal method is one of the most common and efficient synthesis methods. It also has the advantages of high purity, good crystallinity and uniform dispersion.

Due to its unique plasmon resonance effect and light-to-heat conversion characteristics, noble metal nanoparticles can perform optical absorption and energy transfer, making them widely used in photosensitive, catalysis, biosensing, fluorescent labeling and other fields.

At present, many researchers combine noble metals such as Au, Ag, and Pt with rare-earth luminescent materials by using core-shell structure preparation methods and surface modification methods, such as wrapping gold nanoparticles in coordination polymers. To ensure the stability of the gold core, on the other hand, the nano-gold core is functionalized by using the special properties of the outer coordination polymer.

Literature [Dalton Transactions, 2014, 43(39), 14720–14725] synthesized Au/Y ₂ O ₃ :Eu ³⁺ nanotubes by hydrothermal synthesis and vacuum extraction, and studied the effect of Au content on yttrium-europium complexes. The influence of luminescent properties, the literature [Journal of Physical Chemistry C, 2015, 119 (32) 18527-18536] uses the hydrothermal synthesis method to combine Au nanorods with NaGdF ₄ doped with Yb ³⁺ and Er ³⁺ , and the synthesized The core-shell structure of Au Nanorods@NaGdF ₄ /Yb ³⁺ , Er ³⁺ exhibits good upconversion luminescence, magnetic and photothermal effects, and has potential applications in bioimaging and photothermal therapy.

Nowadays, the methods that have been developed to incorporate metal particles into MOF materials include solution infiltration method, solid phase grinding method, surface grafting method and metal-organic chemical vapor deposition method, but these methods are easy to damage the pores of MOF materials, and are also easy to Aggregation occurs, and some researchers [Nanoscale, 2015, 7(3) 1201-1208] used superparamagnetic Fe ₃ O ₄ as the center of the core, combined with gold nanoparticles, and used the method of layer-by-layer assembly to report for the first time Au-Fe ₃ O ₄ @MIL-100(Fe) core-shell structure was synthesized for the efficient reduction of aryl compounds over a magnetically recoverable catalyst.

In recent years, the noble metal rare earth nano-core-shell structure mainly includes the combination of noble gold and rare earth fluoride, rare earth oxide, silicon dioxide, titanium dioxide, etc. However, the combination with rare earth coordination polymers is relatively small.

Contents of the invention

The purpose of the present invention is to provide a method for preparing gold@rare earth coordination polymer nanoparticles. In the present invention, a rare earth coordination polymer with excellent performance is selected as the shell, and the rare earth coordination polymer is successfully synthesized by a mixed solvothermal synthesis method. Coated on the surface of gold nanoparticles, the thickness of the shell and the size of the core of the target product can be adjusted by adjusting various synthesis conditions of the precursor. Possibly, it has a good potential application prospect.

Due to its unique plasmon resonance effect and light-to-heat conversion characteristics, noble metal nanoparticles can perform optical absorption and energy transfer, making them widely used in photosensitive, catalysis, biosensing, fluorescent labeling and other fields. Due to the core-shell structure It is widely used in biological functional materials, optical materials, magnetic functional materials and catalytic functions. Therefore, the purpose of the present invention is to combine Au nanoparticles with rare earth coordination polymers, and the product has both Au nanoparticles and rare earth coordination. properties of polymers.

The process realized in the present invention is as follows: under solvothermal conditions, the seed-mediated method is used to synthesize gold nanoparticles, and then the mixed solvothermal method is used to synthesize gold@rare earth coordination polymer nanospheres. The average particle size of the product balls is about 100nm. The method is not only simple, but also has good dispersion and stability.

The concrete steps that the present invention realizes are as follows:

1. Using CTAB as the protective agent and HAuCl ₄ 3H ₂ O as the raw material, the gold nanoparticles with a particle size of about 20nm were synthesized by the seed-mediated method;

2. Using rare earth nitrate hexahydrate and meso-2,3-dimercaptosuccinic acid as reaction reagent, water and DMF as mixed solvent;

3. Dissolve 0.1mmol of meso-2,3-dimercaptosuccinic acid in 18mL of water, heat and stir until completely dissolved, then add 1ml of 0.035mol/L sodium citrate solution, stir for five minutes, then add 1ml of gold nano Particle solution, stirred for five minutes, set aside, take 0.1mmol rare earth nitrate hexahydrate and dissolve in 5ml DMF solution, mix the above two solutions, stir for 20min, and place in 50ml polytetrafluoroethylene lining, put in 80℃ Reaction in the oven for 3h;

4. After the reaction, cool down to room temperature naturally, wash with absolute ethanol and distilled water several times alternately, and dry in a vacuum oven at 60°C for 12 hours to obtain gold@rare earth coordination polymer nanoparticles.

In the present invention, by selecting the raw material formula, meso-2,3-dimercaptosuccinic acid is an organic linker, mainly because (i) meso-2,3-dimercaptosuccinic acid contains a mercapto group, which can be combined with Au Form a relatively stable Au-S bond; (ii) meso 2,3-dimercaptosuccinic acid can be completely deprotonated or partially deprotonated, and can have a variety of coordination modes; (iii) internal The carboxyl group of racemic 2,3-dimercaptosuccinic acid has rich coordination modes, which is beneficial to the construction of rare earth coordination polymers.

The present invention needs to go through a solvent heat treatment process, the oven reaction temperature is 80° C., and the reaction time is 3 hours.

The technical effect of the present invention is: the present invention adopts solvothermal method to synthesize gold@rare earth coordination polymer core-shell structure nanoparticles, synthesized under solvothermal conditions, the synthesis steps are simple, and the thickness of the shell and core of the target product can be adjusted. Precise control of size, etc., the present invention uses a mixed solvothermal method to synthesize the precursor. Since the reaction is in a closed environment, the synthesized precursor is uniform and difficult to agglomerate. The average particle size of the gold@rare earth coordination polymer core-shell structure nanoparticle The diameter is 100nm and the distribution is uniform. At present, micro-nano materials with core-shell structure have great application potential in the fields of chemical catalysis, biomedical engineering, optical imaging and drug release, so this product has potential application value in the above fields.

Description of drawings

Fig. 1 Transmission electron microscope image of gold@rare earth coordination polymer core-shell structure nanoparticles.

Fig. 2 XRD patterns of gold@rare earth coordination polymer core-shell nanoparticles.

In the figure, Fig. 1 (a) and (b) are the transmission electron micrographs of gold nanoparticles, and Fig. 1 (c) and (d) are the transmission electron micrographs (XRD diffraction patterns) of gold nanoparticles in complex rare earth coordination polymers Measured with Rigaku/Max-3A X-ray diffractometer (CuKα radiation, ); transmission electron microscope pictures were obtained on JEOL-2010 transmission electron microscope in Japan, accelerating voltage 200kV).

detailed description

The beneficial effects of the present invention will be described in detail below in conjunction with the embodiments of the accompanying drawings, aiming at helping readers better understand the essence of the present invention, but not limiting the implementation and protection scope of the present invention.

Embodiment one

A method for preparing gold@rare earth coordination polymer nanoparticles. The specific steps are: 1. Using CTAB as a protective agent and HAuCl ₄ 3H ₂ O as a raw material, using a seed-mediated method to synthesize nanoparticles with a particle size of about 20nm gold nanoparticles;

2. Rare earth nitrate hexahydrate and meso-2,3-dimercaptosuccinic acid are used as reaction reagents, and water and DMF are used as mixed solvents;

3. Dissolve 0.1mmol of meso-2,3-dimercaptosuccinic acid in 18mL of water, heat and stir until completely dissolved, then add 1ml of 0.035mol/L sodium citrate solution, stir for five minutes, then add 1ml of gold nano Particle solution, stirred for five minutes, set aside, take 0.1mmol rare earth nitrate hexahydrate and dissolve in 5ml DMF solution, mix the above two solutions, stir for 20min, and place in 50ml polytetrafluoroethylene lining, put in 80℃ Reaction in the oven for 3h;

4. After the reaction, cool down to room temperature naturally, wash with absolute ethanol and distilled water several times alternately, and dry in a vacuum oven at 60°C for 12 hours to obtain gold@rare earth coordination polymer nanoparticles.

Embodiment two

A method for preparing gold@rare earth coordination polymer nanoparticles, the specific steps of which are: using CTAB as a protective agent, HAuCl ₄ ·3H ₂ O as a raw material, and using a seed-mediated method to synthesize gold nanoparticles with a particle size of about 20nm Particles, 1 mL of gold nanoparticles, 1 mL of 0.035 mol/L sodium citrate aqueous solution, 5 mL of ethanol solution of europium nitrate and 18 mL of mesogenic 2,3-dimercaptosuccinic acid aqueous solution were added to a volume of 50 mL of polytetrafluoroethylene In the ethylene liner, stirred for 20 minutes, and then placed in an oven at 80 ° C for 3 hours to obtain gold@rare earth coordination polymer nanoparticles.

The purity specification of the rare earth nitrate hexahydrate is analytically pure, and the content of the meso-2,3-dimercaptosuccinic acid is 98%.

In the present invention, by selecting the raw material formula, meso-2,3-dimercaptosuccinic acid is an organic linker, mainly because (i) meso-2,3-dimercaptosuccinic acid contains a mercapto group, which can be combined with Au Form a relatively stable Au-S bond; (ii) meso 2,3-dimercaptosuccinic acid can be completely deprotonated or partially deprotonated, and can have a variety of coordination modes; (iii) internal The carboxyl group of racemic 2,3-dimercaptosuccinic acid has rich coordination modes, which is beneficial to the construction of rare earth coordination polymers.

The present invention needs to go through a solvent heat treatment process, the oven reaction temperature is 80° C., and the reaction time is 3 hours.

Referring to Figure 1, it is a TEM image of gold@rare earth coordination polymer core-shell structure nanoparticles, and Figure 1 (a) and (b) are transmission electron microscope images of gold nanoparticles. It can be seen from the figure that gold nanoparticles have good dispersion, The particle size is about 20nm. Figure 1(c) and (d) are transmission electron microscope images of gold nanoparticles composite rare earth coordination polymers. It can be observed from the figures that the compound has a core-shell structure with an average particle size of about 100nm and a crystal plane of 0.213nm. The spacing is clearly visible, corresponding to the (111) crystal plane of the cubic phase Au, indicating that gold nanoparticles have been successfully encapsulated in the rare earth coordination polymer.

Referring to Figure 2, it is the XRD pattern of the gold@rare earth coordination polymer core-shell structure nanomethod. It can be seen from the figure that all the peaks of the sample are completely consistent with the standard card of Au in the cubic phase (JCPDS 04-0784), indicating that the gold nanoparticles have been Successfully coated with rare earth coordination polymers, the final product is gold@rare earth coordination polymer core-shell structure nanoparticles.

The above-mentioned embodiments are only descriptions of preferred implementations of the present invention, and are not intended to limit the scope of the present invention. Variations and improvements should fall within the scope of protection defined by the claims of the present invention.

Claims (3)

1. a kind of method for preparing golden@rare earth coordination polymers nano-particle, it is characterised in that (1) with CTAB as protective agent, HAuCl₄·3H₂O is raw material, and using seed mediated method, synthesis particle diameter is about the gold nano grain of 20nm；

(2) it is reaction reagent with six hydrated rare-earth nitrate and meso DMSA, water and DMF are molten to mix Agent；

(3) 0.1mmol meso DMSAs are dissolved in 18mL water, heating stirring to being completely dissolved, then The sodium citrate solution of 1ml 0.035mol/L is added, is stirred five minutes, add 1ml gold nano grain solution, stir five points Clock, it is standby, take the hydrated rare-earth nitrate of 0.1mmol six and be dissolved in 5ml DMF solutions, above-mentioned two solution is mixed, stirring 20min, is placed in the polytetrafluoroethyllining lining of 50ml, is put into 80 DEG C of baking oven and reacts 3h；

(4) after question response terminates, room temperature is naturally cooled to, is alternately washed for several times, in 60 DEG C of vacuum with absolute ethyl alcohol and distilled water After drying 12h in drying box, golden@rare earth coordination polymers nano-particle is obtained.

2. a kind of method for preparing golden@rare earth coordination polymers nano-particle according to claim 1, it is characterised in that Take step one and obtain the gold nano grain of product 1mL, the sodium citrate aqueous solution of 1mL 0.035mol/L, the second of 5mL europium nitrates Alcoholic solution and the 18mL meso DMSA aqueous solution are added in the polytetrafluoroethyllining lining that volume is 50mL, are stirred 20min is mixed, after being then placed in reacting 3h in 80 DEG C of baking oven, golden@rare earth coordination polymers nano-particle is obtained.

3. a kind of method for preparing golden@rare earth coordination polymers nano-particle according to claim 1, it is characterised in that The pureness specifications of the six hydrated rare-earths nitrate are pure for analysis, and the content of the meso DMSA is 98%.