Synthesis Of Two Nitrogen-Containing Metal Organic Complexes And Study On Their Catalytic Properties

Substances formed by metal ions or metal atoms as the center and combining with organic compounds in whole or in part through coordination bonds are called metal-organic complexes.The synthesis and application of nitrogen-containing metal organic complexes is an interesting field.These complexes have a variety of structures and have very important applications in the fields of industrial catalytic,materials science and life science.In the field of organic catalysis,nitrogen-containing organic ligands can complexate various metals,providing good catalytic effects for coupling reactions such as Heck,Suzuki and Henry coupling reactions.Because of the structure variability of nitrogen-containing metal organic complexes,the design of water-soluble complexes that can be used for separation and recovery will provide impetus for the development of green chemistry.In the field of electrocatalysis,although carbon materials with good electrical conductivity,rich resources,cheap and easy to obtain are substitutes for noble metal catalysts,the electrocatalytic activity of carbon materials is poor,and heteroatom doping,especially metal atom doping,can significantly improve the electrocatalytic activity of carbon materials.Therefore,nitrogen-containing metal organic complexes provide a good template for the doping of carbon materials.In this paper,we synthesized two nitrogen-containing metal organic complexes with different structures and applied them to organic catalysis and electrocatalysis respectively.The main work is as follows:1.A novel surface-active preparation ligand containing N biteeth was synthesized and complexed with palladium chloride to form a homogeneous catalyst with good water solubility,labeled as Pd-L.By adjusting the length of flexible carbon chain and non-quaternary ammonium salinization,two catalysts with different structure were prepared,labeled as Cat1 and Cat2 respectively,for the comparative study of different structure catalysts.The molecular composition and structure of the homogeneous catalyst with good water solubility were determined by NMR,FT-IR,TG.The yield of the catalytic reaction was determined by gas chromatography.By applying it to Heck coupling reaction,its catalytic reaction in green solvent water and ethanol was successfully realized,with stable reaction and high catalytic efficiency.The reaction conditions were screened and optimized from the aspects of solvent ratio,catalyst dosage,reaction time and reaction temperature.The optimum reaction conditions were as follows:1 m L solvent（water:ethanol=1:1）,4 mol%catalyst Pd-L,85℃reaction conditions for 1.5 hours,and the optimized yield reached 96%.In addition,the problem of catalytic recycling was explored.After the completion of the reaction,ethanol was removed by rotary evaporation,and the product was extracted with ethyl acetate,and the catalyst remained in the aqueous phase,and the substrate was continued to be added.The catalyst recycling could be realized,and the yield remained above 80%after 4 cycles.2.A nitrogen-containing ligand with large ring structure of Schiff base was synthesized.The coordination metal cobalt formed a nitrogen-containing metal organic complex,which was labeled as Co-L.Schiff base nitrogen-containing metal organic complex（Co-L）was synthesized by simple method and the product was easy to obtain.Co-L is an aromatic molecule containing nitrogen atoms,which has abundantπelectrons,and can be combined with carbon nanotubes byπ-πconjugation to obtain excellent performance of electrocatalyst（Co-LCNT）.The physical and chemical properties of the catalyst were characterized by SEM,TEM,XRD,Raman,XPS and BET.When applied to OER,its overpotential reaches 311 mV and Tafel slope is 110 mV dec^-1,showing good OER performance.In addition,Co-LCNT has a good electrocatalytic performance for ORR with an initial potential of 0.94 V and a half-wave potential(E_1/2)of 0.85 V,and shows excellent cycle durability.The practical application of Co-LCNT in energy devices was investigated.It showed high catalytic activity for rechargeable Zn-air batteries,and the maximum output power density reached 140 mW cm^-2.