Preparation And Properties Of Metal-organic Complexes Based On N-heterocyclic Imidazolium Cations

In recent years,supramolecular chemistry has become an important branch of chemistry because of its special physical and chemical properties.the development of a series of supramolecular self-assemblies also provides abundant catalyst samples for supramolecular catalysis.Among them,metal-organic supramolecular coordination compounds driven by coordination self-assembly play an important role.The microenvironment of the cavity in metal organic cage can use specific host-guest interactions to change the rate and selectivity of the reaction.Based on this,three kinds of imidazolyl metal-organic supramolecules with different structures were obtained by coordination assembly of N-heterocyclic imidazolium cationic ligands with calixarene metal clusters,and their structures were characterized by X-crystal diffraction experiments,PXRD,BET,TG,FT-IR and other means.According to its structural characteristics,the catalytic performance of triangular prism metal organic cage modified metal Pd in Suzuki coupling reaction was preliminarily explored.This paper consists of four chapters:Chapter 1: introduction,which introduces the concept and characteristics of supramolecular chemistry and the assembly methods of metal organic supramolecular compounds.The geometric structure types of metal-organic molecular cages and their applications in catalysis are discussed.Finally,the research significance of this paper is briefly expounded.Chapter 2: based on coordination self-assembly,three kinds of metal-organic supramolecules with different structures were synthesized from rigid and curved N-heterocyclic imidazolium cationic dicarboxylic acid ligands,thio-calixarenes and metal zinc and cobalt by solvothermal method.Through spectral analysis,it is determined that they are triangular prism metal-organic cage,metal-organic nanotube and metal-organic one-dimensional chain,respectively.The results show that by adjusting the kinds of metals,the steric hindrance of ligands and the corresponding reaction conditions,metal-organic supramolecular coordination compounds with different geometric structures can be obtained.Based on the wide application of N-heterocyclic carbene in catalysis,the construction of this series of metal-organic supramolecular complexes provides a series of materials for the development of new N-heterocyclic carbene catalysts.Chapter 3: in order to make full use of the characteristics of metal-organic cage cavity to simulate biological enzyme catalysis and the advantage that carbene ligands can be functionalized,we preliminarily explored the performance of triangular prism cage modified catalytic center Pd to catalyze Suzuki coupling reaction.The results showed that compared with the small molecular N-heterocyclic imidazole cationic catalyst,the supramolecular cage catalyzed Suzuki coupling reaction had unique advantages such as high reaction yield,fast reaction rate and certain catalytic activity at low catalyst loading.Chapter 4: a summary of the work of this paper.