LU500932B1 - Method for preparing zinc blende structure cadmium sulfide magic cluster with uniform sizes - Google Patents

Abstract

Described is a method for preparing a cadmium sulphide magic cluster with a uniform zinc- blende structure is provided, which relates to the conversion of three cadmium sulphide magic clusters with different sizes. The product of cadmium sulphide magic number cluster was obtained by the reaction of cadmium acetate with N, N '-diphenylthiourea at high temperature and atmospheric pressure in organic phase isolated from air.The metal precursor is inorganic salt cadmium acetate of metal element cadmium of group IIB in the periodic table of elements, and the inorganic salt cadmium acetate and small molecular organic ligand containing carboxyl are dissolved in mixed organic solution of benzylamine and 1,2,4-trimethylbenzene, and the molar ratio of the organic ligand to the cadmium acetate is more than 2:1. The preparation method does not contain expensive noble metals and metal precursors and has mild reaction conditions, and is suitable for preparing the semiconductor cadmium sulphide magic cluster in an organic phase. The invention aims at developing an efficient synthesis strategy of the cadmium sulphide magic number cluster, realizing the controllable preparation of the cadmium sulphide magic number cluster protected by a small molecular organic ligand containing carboxyl, obtaining the optimal synthesis method and accurate structural information of the material, and understanding the stability of the cadmium sulphide magic number cluster, exploring the application of cadmium sulphide magic cluster in catalysis and other aspects, and promoting the development of cadmium sulphide magic cluster in chemistry and physics.

Description

METHOD FOR PREPARING ZINC BLENDE STRUCTURE CADMIUM SULFIDE MAGIC LU500932

CLUSTER WITH UNIFORM SIZES Technical field The invention relates to a method for preparing a zinc blende structure cadmium sulphide magic cluster with uniform sizes.

Background art Quantum Dots (QDs) are semiconductor nanocrystals affected by the quantum confinement effect in three-dimensional space. Due to their high visible light absorption coefficient, multiple excitons, tenable band gap and solution processability, they have broad application prospects in solar cells, light-emitting devices, optical biomarkers and other fields. Quantum dots (QDs) are a new type of inorganic luminescent materials. It has high fluorescence efficiency, and its size is about 1-20 nm. The properties of quantum dot materials can be tuned according to the size of the materials, since their properties are largely dependent on the size of the materials. In recent years, researchers have discovered semiconductor Magic Size Clusters (MSCs) with a single size in the synthesis of conventional quantum dots. It has flexible and controllable chemical properties.

However, most of the synthesis methods of Cadmium sulphide (CdS) magic clusters are complex, the synthesis conditions are harsh, the synthesis time is long, and the structure and composition are uncertain, so it is difficult to obtain uniform and stable CdS magic clusters and analyse their structure-activity relationship, which greatly limits their application in magnetic, optical, acoustic, thermal, electrical, superconducting and other fields.

Therefore, it is an urgent problem for those skilled in the art to develop a method for synthesizing uniform and stable cadmium sulphide clusters with simple operation, mild reaction conditions and short reaction time.

Summary of the invention Aiming at the problems, the invention provides a method for preparing a cadmium sulphide magic cluster by a high-temperature thermal injection method, which can effectively overcome the problems of uncertain structure and composition and the like.

The method for preparing the cadmium sulphide magic cluster includes the following steps of: reacting a metal precursor and N, N '-diphenyl thiourea in a mixed organic solution of non- water-soluble amine and 1, 2, 4-trimethylbenzene to obtain a corresponding cadmium sulphide magic number cluster product. The metal precursor is selected from inorganic salt cadmium acetate of metal element cadmium of group IIB in the periodic table of elements, and a small molecular organic ligand containing carboxyl are dissolved in a mixed organic solution of benzylamine and 1, 2, 4-trimethylbenzene. The molar ratio of the organic ligand to the inorganic salt of the metal element is more than 2:1. The molecular weight of the small molecular organic, 500932 ligand containing carboxyl is preferably less than or equal to 200.

Experiments show that under the conditions of high temperature, normal pressure and inert gas protection, N, N '-diphenylthiourea can react with the metal precursor in a mixed organic solution of the non-water-soluble amine and the 1,2,4-trimethylbenzene by a high-temperature thermal injection method to generate a corresponding cadmium sulphide magic number cluster product. Among them, in the metal precursor composed of the inorganic salt of the metal element and the small molecular organic ligand containing carboxyl, the small molecular organic ligand mainly acts to stabilize the cadmium sulphide magic cluster product generated in the organic solution. Experiments show that when the content of the organic ligand is too low, precipitates are generated as the reaction proceeds, has a certain adverse effect on the smooth progress of the reaction. Therefore, on the premise that the reaction can be carried out smoothly and fully, in order to reduce the waste of raw materials, it is generally feasible to control the molar ratio of the organic ligand to the inorganic salt of the metal element within the range of (4-6): 2, for example, the molar ratio of the organic ligand to the inorganic salt of the metal element is controlled to be

2.5:1 is a good choice.

The N, N '-diphenyl thiourea is added into the metal precursor solution containing cadmium through a high-temperature thermal injection method, and the corresponding cadmium sulphide magic cluster product can be generated through immediate reaction. Although the metal precursor and N, N "-diphenylthiourea can generate the cadmium sulphide magic cluster under most of the feeding ratios, the feeding amount of the metal precursor is too large, and the reaction rate is affected. Preferably, the molar ratio of the inorganic salt cadmium acetate to the N, N '- diphenylthiourea in the metal precursor is 4:1.

The non-water-soluble amine is preferably benzylamine. Taking benzylamine as an example, the experiment shows that when the organic solvent 1,2,4-trimethylbenzene is used as the dispersant, the optimal volume ratio of benzylamine to 1,2,4-trimethylbenzene is 0.01: 1.

The concentration of the inorganic salt cadmium acetate in the metal precursor in the reaction system can be generally controlled to be less than or equal to 0.04 mol/L, so as to avoid the adverse effect of precipitation on the smooth reaction.

The metal inorganic salt in the metal precursor is preferably non-water-soluble cadmium salt cadmium acetate.

Among the small molecular organic ligands containing carboxyl, p-tert-butylbenzoic acid is preferred.

Obviously, based on the above disclosure of the present invention, other modifications, substitutions or changes in various forms can be made without departing from the above basic technical idea of the present invention according to ordinary technical knowledge and common means in the art.

The foregoing aspects of the present invention will be described in further detail below with 500932 reference to the following detailed description in the form of examples. This should not be construed as limiting the scope of the above subject matter of the present invention only to the following examples. Any technology implemented based on the above contents of the present invention falls within the scope of the present invention. Brief Description of the Drawings In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required to be used in the description of the embodiments or the prior art will be briefly described below. It is obvious that the drawings in the following description are only the embodiments of the present invention, and for those skilled in the art, without creative efforts, other figures may also be obtained from the provided figures. FIG. 1 is an ultraviolet absorption spectrum of three cadmium sulphide magic clusters with different sizes obtained by a high-temperature thermal implantation method, and the three cadmium sulphide magic clusters with different sizes are respectively denoted as CdS MSC-326, CdS MSC-345, and CdS MSC 360. FIG. 2 is a photograph of a crystal of a cadmium sulphide magic cluster CdS MSC-326 obtained by using a solvent diffusion method. FIG. 3 is a molecular diagram of the core structure of the cadmium sulphide magic cluster CdS MSC-326 determined by single crystal X-ray diffraction. FIG. 4 is a powder X-ray diffraction pattern of a cadmium sulphide magic cluster CdS MSC-

326. FIG. 5 is a powder X-ray diffraction pattern of a cadmium sulphide magic cluster CdS MSC-

345. FIG. 6 is a Fourier infrared spectrogram of a cadmium sulphide magic cluster. FIG. 7 is an ultraviolet spectrum diagram of the cadmium sulphide magic cluster conversion. FIG. 8 is a fluorescence spectrum and an ultraviolet absorption spectrum of the cadmium sulphide magic cluster. Detailed description of embodiments In the following, the technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the drawings of the specification. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by aperson of ordinary skill in the art without creative efforts are within the scope of protection of the present invention. In order to better understand the present invention, the following examples are used to further illustrate the present invention in detail, but should not be construed as a limitation of the present invention, and some non-essential improvements and adjustments made by those skilled in he 500932 art according to the above disclosure are also considered to fall within the scope of protection of the invention. The invention relates to a method for synthesizing a novel cadmium sulphide magic cluster, which includes the following steps: |, synthesizing a metal precursor: dissolving cadmium acetate and p-tert-butylbenzoic acid in a mixed organic solvent of benzylamine and 1, 2, 4-trimethylbenzene, and heat at 150°C for 30 minutes under that protection of inert gas to obtain the metal precursor; and Il, thermally injecting a chloroform solution of N, N '-diphenylthiourea into the metal precursor, and continuously reacting at 150°C to generate and obtain the corresponding cadmium sulphide magic cluster. Further, in step |, the molar ratio of p-tert-butylbenzoic acid to cadmium acetate is 2.5 : 1, and the volume ratio of benzylamine to 1,2,4-trimethylbenzene is 0.01 : 1. Further, in the step Il, the concentration of the chloroform solution of N, N '-diphenylthiourea is 0.1 mol/L. Furthermore, the reaction time in step Il was 1.5 min, 7 min and 21 min, respectively.

In the following, the technical solutions of the present invention will be described in combination with specific embodiments, as follows: Embodiment 1 The invention relates to a method for synthesizing a novel cadmium sulphide magic cluster CdS MSC-326, which includes the following steps: The molar ratio of p-tert-butylbenzoic acid to cadmium acetate was 2.5 : 1, the volume ratio of benzylamine to 1,2,4-trimethylbenzene was 0.01 : 1, and the concentration of N, N "- diphenylthiourea in chloroform was 0.1 mol/L.

That is, 0.16 mmol of cadmium acetate and 0.4 mmol of p-tert-butylbenzoic acid were mixed and dissolved in a mixed solvent of 4 mL of 1,2,4-trimethylbenzene and 42 ul of benzylamine, and then heated at 150 °C for 30 min under inert gas. After 30 mins, 0. 4 ml of 0. 1 mol/l N, N '- diphenylthiourea in chloroform was injected into the reaction system, and the reaction was continued at 150°C for 1.5 min to obtain CdS MSC-326.

Embodiment 2 The invention relates to a method for synthesizing a novel cadmium sulphide magic cluster CdS MSC-345, which includes the following steps: The molar ratio of p-tert-butylbenzoic acid to cadmium acetate was 2.5 : 1, the volume ratio of benzylamine to 1,2,4-trimethylbenzene was 0.01 : 1, and the concentration of N, N "- diphenylthiourea in chloroform was 0.1 mol/l.

That is, 0.16 mmol of cadmium acetate and 0.4 mmol of p-tert-butylbenzoic acid were mixed 00932 and dissolved in a mixed solvent of 4 ml of 1,2,4-trimethylbenzene and 42 pl of benzylamine, and then heated at 150°C for 30 min under inert gas. After 30 min, 0.4 ml of 0.1 mol/l N, N '- diphenylthiourea in chloroform was injected into the reaction system, and the reaction was 5 continued at 150°C for 7 min to obtain CdS MSC-345.

Embodiment 3 The invention relates to a method for synthesizing a novel cadmium sulphide magic cluster CdS MSC-360, which includes the following steps: The molar ratio of p-tert-butylbenzoic acid to cadmium acetate was 2.5 : 1, the volume ratio of benzylamine to 1,2,4-trimethylbenzene was 0.01 : 1, and the concentration of N, N "- diphenylthiourea in chloroform was 0.1 mol/l.

That is, 0.16 mmol of cadmium acetate and 0.4 mmol of p-tert-butylbenzoic acid were mixed and dissolved in a mixed solvent of 4 ml of 1,2,4-trimethylbenzene and 42 pl of benzylamine, and then heated at 150°C for 30 min under inert gas. After 30 mins, 0.4 ml of 0.1 mol/l N, N '- diphenylthiourea in chloroform was injected into the reaction system, and the reaction was continued at 150°C for 21 min to obtain CdS MSC-360.

In order to further prove the beneficial effects of the present invention and to better understand the present invention, the properties and application performance of the cadmium sulphide magic cluster described in the present invention are further illustrated by the following test, but it should not be understood as a limitation of the invention. The properties of the product obtained by other determination experiments conducted by a person skilled in the art according to the above invention and the application based on the above properties are also considered to fall within the scope of protection of the present invention.

Experimental example 1structural characterization The crystal structure of the cadmium sulphide magic cluster CdS MSC-326 synthesized in the above embodiment is characterized, and the details are shown in Figures 2 and 3.

It can be seen from FIG. 2 that the crystal of the cadmium sulphide magic cluster CdS MSC- 326 prepared by the synthesis method disclosed in the present invention has a complete shape and is a colourless transparent cubic crystal.

The core structure of the CdS magic cluster CdS MSC-326 was determined as CdzoS1ofrom the single crystal X-ray diffraction of Figure 3. Experimental example 2 characterization measurement (1) Powder X-ray diffraction measurements were performed on the synthesized cadmium sulphide magic clusters CdS MSC-326 and CdS MSC-345, as shown in Figures 4 and 5, respectively.

(2) Fourier transform infrared spectroscopy of the synthesized cadmium sulphide magic, 500932 cluster is measured, as shown in Figure 6. (3) The ultraviolet absorption spectrum of the synthesized cadmium sulphide magic cluster was measured, as shown in Figure 7. Experiments show that the CdS magic cluster can be transformed from CdS MSC-326 to CdS MSC-345 and then to CdS MSC 360 under the condition of continuous heating at 150°C. (4) The fluorescence spectrum and ultraviolet absorption spectrum of the synthesized cadmium sulphide magic cluster were measured, as shown in Figure 8. In conclusion, the cadmium sulphide magic cluster synthesized by the present invention has a clear structure and composition, and can emit blue light at room temperature.

The synthetic method disclosed and protected by the invention has the advantage of simple operation, strong applicability and convenience for industrial production.

The foregoing description of the disclosed embodiments will enable any person skilled in the art to make or use the invention.

Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention.

So, the present invention is not to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (7)

1. A method for preparing a cadmium sulphide magic cluster, characterized in that comprising: — reacting cadmium acetate and an organic ligand in a mixed organic solution of non-water- soluble amine and 1, 2, 4-trimethylbenzene to obtain a metal precursor solution containing cadmium; and — injecting a chloroform solution of N, N '-diphenylthiourea thermally into the metal precursor solution by adopting a thermal injection method at high temperature to obtain the corresponding cadmium sulphide magic cluster product; — Wherein the metal precursor is cadmium acetate which is an inorganic salt of a metal element cadmium of group IIB in the periodic table of elements; the molar ratio of the organic ligand to the cadmium acetate is more than 2:1; the organic ligand is a carboxylic acid compound, and the molecular weight of a small molecular compound containing carboxyl is preferably less than or equal to 200.

2. The method for synthesizing a cadmium sulphide magic number cluster of claim 1, characterized in that the cadmium acetate and the organic ligand are firstly dissolved in a mixed organic solution of non-water-soluble amine and 1,2,4-trimethylbenzene, heated at 150 °C for 30 minutes to obtain a metal precursor solution containing cadmium, and then the N, N '-diphenylthiourea is added by a high-temperature thermal injection method to obtain the corresponding cadmium sulphide magic cluster product.

3. The method of claim 2, wherein the molar ratio of the organic ligand to the cadmium acetate is2.5:1.

4. The method of claim 1, wherein the organic ligand is p-tert-butylbenzoic acid with a mass of

71.3 mg.

5. The method of claim 1, wherein the molar ratio of cadmium acetate to N, N '-diphenylthiourea is 4:1.

6. The method of claim 1, wherein the water-insoluble amine is benzylamine, and the amount of benzylamine added is 42yl.

7. The method of claim 1, wherein the volume of the 1,2,4-trimethylbenzene is 4 ml.