Study On The Synthesis Of The Imidazole Side Chain Functionalized Indenyl Ligand And Its Complexes

The Group 4 transition metal based catalysts play an important role in olefin polymerization industries. These catalysts have evolutioned from Zeigler-Natta catalysts to metallocene-type catalysts and, further, to non-metallocene ones (for instance, the so-called "constrained-geometry" catalysts, CGCs). Among these types of catalysts, the latter are thought to be one of the most notable highlights what fascinates many researchers because of their special features and remarkable catalytic properties in olefin polymerization. Development of novel CGCs now becomes one of the most active strategies in olefin polymerization catalyst design. A series of half-sandwich titanium(iv) and zirconium(iv) complexes of the type with imidazolyl side-chain functionalized indenyl ligands have been synthesized and characterized in this dissertation.The present investigation comprises two parts. At the first stage, we have developed the synthetic approaches to imidazolyl side-chain functionalized indenyl type ligands by reactions of lithiated imidazoles with pentafulvenes. At this step,1-diethoxymethyl-2-methyl-1H-imidazole and 1-diethoxymethyl-1H-imidazole have been prepared. The further steps of chemical transformations involved lithiation of 1-diethoxymethyl -2-methyl-1H-imidazole and 1-diethoxymethyl-1H-imidazole followed by a reaction with a corresponding fulvene:1,1-diphenylmethylidene-,1-phenylmethylidene-, and/or 1,1-(1-methylethylidene) 1H-indene. Four Cp-(C1 or C2-link)-(2-imidazolyl) ligands, namely:2-[2-(1H-inden-3-yl)-2,2-diphenylethyl]-(4a),2-[2-(1H-inden-3-yl)-2-phenylethyl]-(4b),2-[2-(1H-inden-3-yl)-2-methylpropyl]-(4c), and 2-[2-(1H-inden-3-yl)-2,2-diphenylmethyl]-1H-imidazoles (4d), have been synthesized. An attempt to prepare 2-[2-(1H-inden-3-yl)-2-phenylmethyl]-(4e) and 2-[2-(1H-inden-3-yl)-2,2-dimethylmethyl]-1H-imidazoles (4f) has failed. Compound 4a has been converted into its dilithium derivative.At the second step of the investigation, the prepared ligands were converted into complexes by direct reactions of their CH-forms with tetrakis(dialkylamides) of the Group 4 metal. Four compounds have been obtained:bis (N,N-diethylamido-κN) (2-{2-[(1,2,3,3a,7a-η)-1H-indenyl])-2,2-diphenylmethyl}-1Hmidazolido-κN1)titanium (IV) (6a), bis(N,N-dimethylamido-κN (2-{2-[(1,2,3,3a,7a-η)-1H-indenyl])2,2-diphenylethyl}1H-imidazolido-κN1)zirconium(Ⅳ) (6b), bis(N, N-dimethylamido-κN(2{2-[(1,2,3,3a,7a-η)-1H-indenyl]2-phenylethyl}-1H-imidazolido-κN1)zirconium(IV) (6c) and bis(N,N- dimethylamido-κN)(2-{2-[(1,2,3,3a,7a-η)-1H-indenyl]-2-methylpropyl}-1H-imidazolido-κN1) zirconium(IV) (6d). Trichlorido type complexes, trichlorido(tetrahydrofuran){1-[2-(1-trimethylsilyl-1H-imidazol-2-yl-κN3)-1,1-diphenylethyl]-(1,2,3,3a,7a-η)-1H-indenyl} zirconium (IV) (7a), and trichlorido(tetrahydrofuran){(1,2,3,3a,7a-η)-1-[2-(1-trimethylsilyl-1H-imidazol-2-yl-κN5)-1-methylpropyl]-1H-indenyl}zirconium(IV) (7b), have been prepared by a reaction of amido compounds 6b and 6d with Me3SiCl.Crystal and molecular structures of 7a and 7b have been established by single-crystal X-ray diffraction analyses. All compounds within this research work were characterized by1H and 13C{1H} NMR spectroscopy, GC-MS (organic materials) and elemental analyses. Catalytic activity of the complexes for olefin polymerization will been measured soon.