Mononuclear And Multimetal Compounds Based On Amidine:Synthesis And Catalytic Behavior

In the past few decades, it has been paid considerable attention in searching for alternatives instead of the ubiquitous cyclopentadienyl species. Up to now, the coordination chemistry of amidinate ligands with a wide variety of metals has been well established. The typical amidinate ligand,[RC(NR’)2]-, is fourelectron monoanionic and has a characteristic conjugated N-C-N backbone, through which the negative charge could be delocalized so to forma chelating environment. These ligands can meet the requirements of different metal centers, for the reason that their steric and electronic properties are easily tunable through variation of the substituents on the N-C-N framework. Recently, It is reported that some metal complexes based on diamine ligands have shown to be valuable as olefin polymerization catalysts.The research work of this dissertation focuses on the synthesis and characterization of novel organometallic complexes supported with the amidinate ligands, The details is as following: Chapter1. A background introduction for the topic of this thesis. It including:(1) synthesis and characterization of amidine;(2) the development of amidinate metal complexes;(3) the applications of amidinate metal complexes. Chapter2. A series of neutral amidine compounds were synthesized and characterized by X-ray diffraction crystallography as well as spectroscopic analysis (Scheme1).Chapter3. The silyl-linked bis(amidinate) ligands3a and3b were synthesized incorporating with Aliphatic amines, which was characterized by X-ray diffraction crystallography.(Scheme2)Scheme2The synthetic route of compounds3a,3b and3cChapter4. Synthesize the silyl-linked bis(amidinate) metal complexes, lithium ligand of3a was treated with the group IV metal chlorides MCl4(M=Ti, Zr and Hf)(Scheme3), and lithiumligand of b was treated with the MCl2(M=Mn,Co)(Scheme4), they were characterized by X-ray diffraction crystallography and1HNMR. Upon treatment with MAO, exploring the catalytic activity of complexes3a and3b in the polymerization of ethylene.Scheme4The synthetic route of compounds4d and4eChapter5. A series of bimetallic and multimetallic organometallic compounds were synthesized and characterized by X-ray diffraction crystallography as well as spectroscopic analysis (Scheme5). Upon treatment with MAO, exploring the catalytic activity of complexes3a and3b in the polymerization of ethylene.