Synthesis, Structures And Catalysis Of Imino Metal (Ti, Zr, Sn) Complexes

Amidinate complexes have been the theme of extensive investigation of their chemistry and the research about the ligands containg imine which can be applied as catalysts and materials in organic synthesis, olefin polymerization and engineering plastics is always one of the hottest spots in the realm of organometallics.The purpose of this thesis is on the synthesis of two series of ligands including bridged bis(amidinate) ligand and mono-amidinate ligand by the reaction of addition and substituent using aniline as starting material. Then, a series of organometallic compounds which certainly include the alkali metal and transition-metal organic compounds were obtained by some classic synthetic methods X-ray single crystal diffraction, NMR and GC-MS are employed in the determination of the organometallic compounds. In addition, some of the complexes were applied in the catalysis polymerization of ethene.Chapter One Background of this thesis is described. The Metal and metalloid amide is a part of it. Amidinates are four-electron, three-atom bridged ligands with the general formula of N-C-N and have been proven to be versatile ligands due to the ease of presenting a flexible system for the steric and electronic properties of the resultant metal compounds rationally modified by means of substitution at the terminal nitrogen atoms.The synthesis and structures of all organometallic compounds obtained are expatiated in the Chapter Two, Three and Four. Transition metals generally bond to ligands by covalent bond in organometallic chemistry, while in compound 13, ionic bond is observed. The mechanism for compound 11 or 13 having six-membered ring is investigated in detail. The titanium compounds 14 and 15 are also novel in their structures.Since Ziegler's discovery of the polymerization of ethylene with TiCl₄-AlEt₂Cl catalyst and shortly later Natta's discovery of the stereo-selective polymerization of propylene in early 1950s, much attractive attentions have been focused on the improvement of Ziegler-Natta catalyst system and the polymerization process, which led to accelerate polyolefin industrialization all over the world. From Ziegler's discovery to Kaminsky's metallocene methyllalumoxane catalyst, it is very clearly that organometallic chemistry plays a key role in innovation of polyolefin technology and stands still on the frontier in the area of polyolefin synthesis and process and it has made a great contribution to the progress for worldwide polyolefin industry. Silyl-bridged compounds with anidinate which proved to be potential catalytic performance have been widely investigated in Chapter Five.