Controllable Self-assembly Of Gold Nanoparticles Controlled By Supramolecular Metallocycle

In recent years,with the development of nanoscience and technology,many studies have shown that the aggregate structure formed by inorganic nanoparticles will exhibit different optical,electrical,magnetic,and catalytic activities than individual particles.In particular,it has become an important way for people to develop and explore nanometer components to construct new nanometer materials and devices by controlling nanometer elements.Among them,the nanomaterials constructed by the controllable self-assembly mode of weak interaction between molecules can not only possess the peculiar properties o f nanomaterials themselves,but also provide some special physical and chemical properties for them.At the same time,it can enrich the existing nanomaterials and provide a new platform for the construction of new functional nanocomposites.Though the people have developed a variety of connection ligand and a variety of ways to build nanoparticle aggregation,however due to the microscopic size of nanoparticles itself and larger specific surface area,makes the precise construction of nanoparticle aggregat ion morphology and microscopic structure is challenging,especially in the efficient preparation of nanoparticle aggregation aspects of specific morphology.Supramolecular chemistry is a science composed of chemistry and biology,material science,physics and environmental science,in which the directivity and high bonding ability of metal coordination bond provide an opportunity for the efficient construction of specific topological molecules.Therefore,the introduction of metal coordination bonds to construct specific structures of nanomaterials has gradually attracted people’s attention,especially the introduction of metal coordination bonds to construct supramolecular ligands with specific structures,which provides a new platform for the construction and functionalization of nanoparticle aggregates.In this paper,by means of water-oil interface assembly,supramolecular metallocycle ligands with different number of binding sites are used as the connecting ligands,and by means of guided self-assembly,the gold nanoparticles are assembled into nanoparticles of various shapes in a controllable manner.Based on supramolecular metallocycle ring stiffness and dynamic reversibility,we adjust the influence factors to the successful preparation of various morphology of nanoparticle aggregation and have clear particle spacing of nanoparticles monolayer film,on this basis to explore the method for constructing the universality of nanoparticle aggregation and efficiency,at the same time to build the nanoparticle aggregation and nanoparticles film properties and function.This paper is divided into the following parts:In chapter 1,the classification and research progress of nanomaterials,the research progress of metal nanomaterials and the research status of gold nanoparticles and their aggregates are reviewed.Then,the construction and assembly methods of gold nanoparticles and their aggregates,the construction and development of ligands,the research progress of supramolecular chemistry and their application in nanomaterials are introduced.Finally,the main contents,research methods and results of this paper are briefly described.In chapter 2,we first designed and synthesized three kinds of supramolecular metallocycle ligands with different topological structures by the way of metal coordination bond guiding self-assembly.These supramolecular metallocycle ligands have certain rigidity and stability,and their outer ring modification has different numbers of disulfide groups used for coordination with gold particles.On this basis,the controllability of coordination self-assembly of gold nanoparticles was studied in detail.At the liquid-liquid interface,we induced the assembly of gold nanoparticles with supramolecular metallocycle ligands,and success fully prepared dimers,trimers and hexamers of gold nanoparticles by adjusting the concentration of gold nanoparticles,ligands and the time of assembly.Then we compared the inner diameter of supramolecular metallocycle ligands with the spacing of their corresponding aggregates,proving that supramolecular metallocycle ligands can well regulate the spacing of particles in the assembly body.In addition,through the introduction of bromide ions,it is proved that the aggregate has the ability to dissociate.On the basis of the successful preparation of these nanoparticle aggregates,we further studied the enhancement effect of these aggregates on the surface Raman spectrum,and demonstrated their potential application value.In chapter 3,based on the synthesis of three different topology structure of supramolecular metallocycle ligand controlled induction effect of gold nanoparticles,we use a coordination-induced self-assembly method to coordinately assemble ligands and gold particles at the liquid-liquid interface,on the basis of a large number of experiments,use the supramolecular metallocycle ligands and the success of the preparation of monolayer gold nanoparticles with a dense membrane,investigated the structural regulation of metallocycle ligands o n the assembly of gold nanoparticle membranes.Subsequently,we studied the hydrophilicity and hydrophobicity of both sides of the gold nanofilms,and the experiment confirmed that these monolayer particle membranes had typical asymmetric(Janus)character istics.Based on the characteristics of preparing gold nanofilms,the relationship between the particle spacing,particle size and Raman enhancement effect in the monolayer nanofilms was studied,and the strong enhancement effect of the monolayer gold nano films on Raman spectrum was confirmed.