Studies On Synthesis, Characterization, And Catalytic Properties Of Metal Complexes Supported By Amine-bis(Phenolate)Tetradentate Ligands

The polyolefin as a most widely used polymer material has penetrated into everyaspect of our lives. Polyolefin applications greatly improve people’s living standards,improve the quality of life. Nowadays, the development of polyolefin industry hasbecome an important index of national economy. The design, synthesis of the olefinpolymerization catalysts is the core of the polyolefin industry, which determines themorphology, structure and properties of polymers. With the rapid development ofpolyolefin industry and the increasing demand for polyolefin products with a specialperformance, it is urgent to find a more excellent catalyst with important industrialapplication value.In order to explore the non-metallocene polyethylene catalyst with high activity,high thermal stability, long life, our group designed a series of bridged diamine-bis(phenolate)[N, N, O, O] tetradentate titanium zirconium complexes. This paper arediscussed mainly about synthesis and catalytic properties of titanium zirconiumcomplexes. In the third chapter of this article, a detailed discussion of the synthesis ofthis series of the ligands and metal complexes. The structure of ligands are that:[Me2NCH2CH2N{CH2-(2-OC6H2-3-R-5-tBu)}2][L1H2: R=C(CH3)2Ph, L2H2: R=C(CH3)Ph2, L3H2: R=CPh3]. The structure of the ligands were characterized by1H NMR,13C NMR, MS. The synthesis of titanium complexes using a one-pot method thathas been reported by our group. Under-78℃conditions, to a toluene solution ofligand was added1.1equivalents of TiCl4, Then removing the solvent. The residuescan convert to the corresponding titanium complexes in high yield by heated at140℃under vacuum. Zirconium complexes were obtained by conventional methods of lithiumsalt. The synthesized complexes were characterized by1H NMR,13C NMR, elementalanalysis, X-ray diffraction.In the forth chapter, we conducted further research for the catalytic properties ofcomplexes1-5. Upon activation with methylaluminoxane, complexes of titaniumexhibits a moderate catalytic activity, whereas complexes of zirconium exhibits ultrahigh catalytic activity for ethylene polymerization. In addition, complexes of zirconiumalso exhibits high thermal stability, a long catalyst life. The resulting polymer is a linearpolyethylene, the highest molecular weight Mw up to7.22×104g/mol.