Design And Preparation Of Ruthenium,Iridium And Selenium Catalytic Materials And Their Application In Olefin Conversion

As an important structural unit,olefins widely exist in bioactive molecules and material molecules.As starting materials,they can be easily functionalized and used to synthesize a variety of chemical intermediates and functional frameworks.Since the stereochemistry of olefins(Z/E configuration)greatly affects its chemical,physical,and physiological properties and functions,the highly stereoselective construction of olefins has been the focus of chemists' research.There are many methods to synthesize olefins,but these methods often produce mixtures of olefin stereoisomers.Therefore,it is very important to realize the isomerization of olefins.Ruthenium and iridium complexes are an important class of organic functional materials.They have been widely used in many aspects such as solar cells,but few applications have been reported in catalysis.Therefore,we prepared a variety of ruthenium and iridium complexes,combined with photocatalysis technology to catalyze the isomerization of olefins,and explored whether olefins can be constructed with high stereoselectivity under the catalysis of ruthenium and iridium complexes.In addition,olefin oxidation reaction is also an important part of olefin conversion.Based on the basis of previous research work,this paper designed and synthesized a heterogeneous catalyst,poly-selenide material to catalyze the reaction to achieve efficient oxidation of olefins.The specific content includes the following three parts:1.To explore the relationship between the ultraviolet absorption spectrum and emission spectrum of the ruthenium complexes with different structures of the same metal under the irradiation of a single light source and the catalytic performance of the complexes for the isomerization reaction of olefins.Four kinds of ruthenium metal complexes with different ligands are obtained by covalent bond coordination between metal ruthenium and organic ligands.The structure and photophysical properties were studied using nuclear magnetic resonance hydrogen spectroscopy,infrared spectroscopy,ultraviolet absorption spectroscopy and photoluminescence spectroscopy.The catalytic performance of four ruthenium complexes on the photoisomerization of olefin was studied with photochemical techniques.The results show that the prepared four metal ruthenium complexes have the correct structure,and the metal ruthenium and organic ligands have achieved effective coordination.The maximum absorption wavelength of ruthenium complexes is in the range of 250-280 nm,and they have obvious absorption in the blue region.Therefore,blue light with a wavelength of 256 nm is used as the excitation light source in the photocatalytic reaction.Under the irradiation of blue light,different ruthenium complexes have different catalytic properties.The closer the absorption wavelength of the complex is to the excitation wavelength,the better the reaction effect will be.Therefore,the complex 2-Ru-3 has better catalytic performance than the remaining three ruthenium complexes.The reaction can produce Z-type,thermodynamically stable products with a 60%yield and high stereoselectivity(Z/E>20:1),and there is no E-type,thermodynamically unstable products.The main reason is that the generated Z-type olefin cannot quench the ruthenium photocatalyst,so the configuration cannot be reversed,and the isomerization of the Z-type?E-type cannot occur.The contribution of the emission spectrum to the reaction is not yet clear.2.To explore the relationship between the ultraviolet absorption spectrum and the catalytic performance of the iridium complex for the isomerization of olefins under the irradiation of a single light source.Five kinds of ionic metal iridium complexes were prepared by the coordination of metal iridium,C^N main ligand and N^N auxiliary ligand in sequence.NMR hydrogen spectroscopy,infrared spectroscopy,ultraviolet absorption spectroscopy,and emission spectroscopy were used to study its structure and photophysical properties.At the same time,it combined photochemical techniques to study the catalytic performance of iridium complexes for photoisomerization of olefins.The results show that the maximum absorption wavelength of metal iridium complexes is in the range of 255?270 nm.Therefore,blue light with a wavelength of 256 nm is used as the excitation light source in the photocatalytic reaction.Under blue light irradiation,different iridium complexes have different catalytic properties.The concentration of iridium complex and the solvent will affect the catalytic performance of iridium complex.The complex 3-Ir-3 has better catalytic performance than the other four iridium complexes.Under the condition of 1.0×10-3 mol/L concentration and acetonitrile as the solvent,the reaction can obtain E-type,thermodynamically unstable olefin with 64%yield and high stereoselectivity(E/Z>20:1),and realized the isomerization process of olefin configuration from Z-type to E-type.3.To explore the relationship between the structure of poly-selenide catalytic material and its catalytic performance for oxidative cracking of olefins.Poly-selenide material was obtained by one-step reaction of dihalogenated hydrocarbon and sodium selenide.By screening monomer dihalohydrocarbons,we finally selected 1,4-bischloromethylbenzene as the best monomer.The morphology,structure and surface elemental valence of material were characterized by scanning electron microscope,infrared absorption spectrum and X-ray photoelectron spectroscopy.The experimental results show that the substituents and chemical structures of dihalogenated hydrocarbons can affect the catalytic activity of the prepared materials.The poly-selenide material synthesized from the monomer 1,4-bischloromethylbenzene shows good catalytic performance in the oxidative cracking reaction of olefins,and the reaction can obtain oxidation products with the highest yield of 75%.