Polydentate Nitrogen Ligand Complexes: Synthesis,Characterization And Application

Catalytic olefin polymerization is a most important industrial chemical process.Over 100 million tons of monomers per year?primarily ethene and propene?are converted into durable and versatile polymeric materials with full atom economy and low energy consumption.Addition,the polyolefin materials have been becoming a significant part of industrial production,which largely depends on the efficient design and synthesis of transition metal complex catalysts.On the basis of the above study background and our previous research works,the paper focuses on the designing and synthesis of several polydentate nitrogen ligands?aminosilyl substituted aminopyridinate,phenylhydrazone?and the correspond transition metal complexes.The structures of the obtained new compounds were characterized.In addition,the synthesized phenylhydrazonato zirconium complexes were used as catalysts for ethylene polymerization reaction.Them exhibited moderate catalytic activities toward ethylene polymerization and produced high molecular weight polyethylenes.Moreover,two bis?ferrocenoyl thiourea?compounds were synthesized,their structures and electrochemical behaviors were also investigated.The main research contents in this paper contain four sections as follows:Chapter 1.Introduction to the research background and progress of this thesis:?1?Several important polyolefin catalysts;?2?The general situation of polyethylene materials;?3?The research developments of our group.Chapter 2.One silyamino-substituted aminopyridinato zirconium complex 3a was synthesized and characterized by X-ray diffraction?Scheme 1?.Simultaneously,the four-membered Si₂N₂ core with coplanar aromatic rings 4a-4c were synthesized and characterized by 1H,13 C NMR and X-ray diffraction?Scheme 2?.???Scheme 1 Synthesis of the aminopyridinato zirconium complex 3a ???Scheme 2 Synthesis of the dicyclosilazane compounds 4a-4cChapter 3.The synthesized three phenylhydrazonato zirconium complexes were used as catalysts for ethylene polymerization reaction?Scheme 3?.Upon treatment with MAO,the zirconium compounds 3c-3e showed moderate activity for ethylene polymerization(up to 8.02×10⁴ g·mol^-1?Zr?·h^-1,2.95×10⁴ g·mol^-1?Zr?·h^-1,4.60×10⁴ g·mol^-1?Zr?·h^-1,respectively).The resultant polyethylene in this section possessed high molecular weight and narrow molecular weight distributions.???Schene3Synthesis of the phenylhydrazonato zirconium complexes 3c-3eChapter 4.Two bis?ferrocenoyl thiourea?compounds were synthesized and characterized by NMR,IR,elemental analysis and X-ray diffraction?Scheme 4?,respectively.Comparing with ferrocene,the obtained compounds showed red-shift in the absorption peaks.The electrochemical data showed that the obtained compounds in this part exhibited one-electron reversible or quasi-reversible electrochemical redox behaviors.Furthermore,both compounds 1 and 2 displayed potential antitumor activity against human Hep G2 cells.???Scheme 4 Synthesis of the bis?ferrocenoyl thiourea?compounds...