Synthesis, Reactivity And Catalytic Behavior Of Metal Complexes Bearing The Linked-bis(Amidinate) Ligands

The development of catalysts for olefin polymerization is a hot topic in the field of organometallic chemistry. It has experienced three stages: Ziegler-Natta catalyst, metallocene catalysts and the transition metal complex catalysts. In order to design and tailor polymer molecules and to precisely control the polymer structure, the researchers have developed the metallocene catalyst having a single active center. As the sensitivity to the oxygen atom and the functional groups, the metallocene catalyst is not suitable for the copolymerization of ethylene and polar monomer. On the contrary, the weak affinity to the oxygen atom and the functional groups of the non-metallocene transition metal catalyst can make the ethylene polymer with polar monomers under mild conditions. Therefore, much attention was paid to develop the new generation of non-metallocene transition metal catalyst.The main content of this thesis is to synthesis a series of bridged bis(amidinate) transition metal complexes by modifying the type and location of the substituent or changing the central metal ion. The compounds were characterized by the X-ray diffraction crystallography as well as spectroscopic analysis. The catalytic activities towards the olefin polymerization of the complexes were investigated. The details are as following:Chapter 1. A background introduction for the topic of this thesis. It includes:(1) the characterization of the metal complexes based on the amidine ligand; (2) the synthetic methods of the metal complexes based on the amidine ligand; (3) the applications and the development of the metal complexes based on the amidine ligand.Chapter 2. A series of group(Ⅳ) metal compounds 2a,2b and 2c based on the linked bis(amidine) ligands were synthesized and characterized by X-ray diffraction crystallography as well as spectroscopic analysis (Scheme1). The catalytic properties of the complexes were studied.Scheme 1 The synthetic route of compounds 2a、2b�'�2cChapter 3. A series of zirconium compounds 3a、3b and 3c with the coordination number of 7 based on the linked bis(amidine) ligands were synthesized, which was characterized by X-ray diffraction crystallography as well as spectroscopic analysis. The catalytic properties of the complexes were studied. (Scheme 2)Scheme 2 The synthetic route of compounds 3a、3b�'�3cChapter 4. A series of bimetallic organometallic compounds 4a,4b and 4c based on the linked bis(amidine) ligands were synthesized, which was characterized by X-ray diffraction crystallography as well as spectroscopic analysis. The catalytic properties of the complexes were studied. (Scheme 3)Scheme 3 The synthetic route of compounds 4a、4b and 4c...