Synthesis And Characterization Of Penta-heterocyclic Including N,O,S Amion Transition Metal Catalysts For Olefin Polymerization

Since Brookhart synthesized the classical bis?imino?pyridine late transition metal catalysts for olefin polymerization,more and more attentions were paid to this kind of highly efficient catalysts.In the catalysts,the conjugate structure of the ligand and large steric hindrance of the side chain substituents were thought to be the key factors for high activities for olefin polymerization.Therefore,the most researches have focused on adjusting and changing the ligand structure in the field.The paper uses the Brookhart bis?imino?pyridine ligand as the model,and modifies the ligand by the electronic effect and the steric effect so that we can develop the new penta-heterocyclic catalysts for olefin polymerization.And then the catalysts are used in olefin polymerization experiments to detect their catalytic performance.The main works are as following:1.2-Acetylpyrrole,2-acetylthiophene and 2-acetylfuran react with a series of aromatic amines under the microwave irradiation by Schiff-base condensation reaction respectively to prepare the new types of mono?imino?pyrrole compounds,mono?imino?thiophene compounds and mono?imino?furan compounds.The structures of ligands are characterized by X-ray single crystal diffraction,1H NMR,IR and elemental analysis.The spatial structures of the ligands had been discussed by the analysis of molecular structural data.Meanwhile,the reaction mechanisms of Schiff-base condensation are also discussed.2.By the reactions of mono?imino?pyrrole compounds,mono?imino?thiophene compounds or mono?imino?furan compounds with the transition metal Ni?II?chloride,a series of novel centrosymmetric late transition metal complexes are prepared by liquid-phase reaction or hydrothermal reaction.The experiment results show that part of mono?imino?pyrrole compounds react with Ni?II?chloride,the structures of these complexes are characterized by X-ray single crystal diffraction.However no indication shows that the reaction occurres between mono?imino?thiophene ligands,mono?imino?furan ligands and Ni?II?chloride both in liquid-phase reaction and hydrothermal reaction.With the oxygen and sulfur atoms of the furan and thiophene core of these ligands being rather poor donors,the corresponding complexes had not obtained.The mono?imino?pyrrole late transition metal complexes?1d,2d,4d,5d,10d?was experimented in olefin polymerization/oligomerization under 20? and 0.5MPa.After the reaction ended,the solution is clear pale yellow.Then we found the kind of complexes have great effect on olefin polymerization/oligomerization,and its catalytic activity is 1.83⁴.23kg·mol^-1?Ni?·h^-1.1d and 2d have higher selectivity for C₆.4d and 5d have higer selectivity for C₈,and then 10 d have higher selectivity for C₄.