Synthesis Of N,N Bidentate Nickel Complexes And Their Applications In Ethylene Polymerization

This dissertation focuses on design and synthesis of a series of nickel complexes based on6,7-dihydroquinolin-8(5H)-one and study their catalytical behaviors toward ethylene transformation. The ligands are characterized by NMR spectra, IR spectra and elemental analysis. The complexes are detected by IR spectra and elemental analysis. Some of them are further characterized by single-crystal X-ray diffraction. During the investigation of their activities toward ethylene polymerization, the multiply factors were considered and discussed in detail, including the pressure of ethylene, the amount of catalyst and co-catalyst, the species of cocatalyst, temperature, etc. Activated with MAO or Et2AlCl, the precatalysts exhibited high activities and obtained high branched polymer with relatively low molecular weight. Four parts are included in this dissertation as follows:Part I:The progress of catalysts used in polymerization and/or oligomerization of ethylene is summarized. The discovery and application of the typical catalyst in industry are introduced especially for nickel complexes.Part II:A series of ligands including bulky substituent were synthesized and characterized by NMR spectra, IR spectra and elemental analysis. Partâ…¢:A series of N,N bidentate nickel complexes were synthesized and characterized by IR spectra, elemental analysis and single-crystal X-ray diffraction. Seen from the single crystal structure, two molecules of complex were combined with two chloride atoms under the assistance of oxygen atom of the solvent. The coordinate geometry around the nickel center can be described as a distorted octahedronPartIV:The activities of these complexes toward ethylene polymerization were investigated. Upon treatment with MAO or Et2AlCl, these nickel complexes showed high activities. Polymers with different properties can be obtained under various conditions.