Bis(1-methylethenyl-cyclopentadienyl)zirconium dichloride (7a) was prepared by a fulvene route. Photolysis at 0 degrees C with Pyrex-filtered UV light resulted in a rapid and complete intramolecular [2+2]cycloaddition reaction to yield the corresponding cyclobutylene-bridged ansa-zirconocene dichloride isomer (8a). This is one of the rare examples of an organic functional group chemistry that l...

Reduction of Zr(IV) metallocenium cations with sodium amalgam (NaHg) produces EPR signals assignable to Zr(III) metallocene complexes. The chloro-bridged heterodinuclear ansa-zirconocenium cation [(SBI)Zr(μ-Cl)2AlMe2](+) (SBI = rac-dimethylsilylbis(1-indenyl)), present in toluene solution as its B(C6F5)4(-) salt, thus gives rise to an EPR signal assignable to the complex (SBI)Zr(III)(μ-Cl)2AlMe...

A series of dinitrogen-bridged dimolybdenum-dinitrogen complexes bearing metallocene-substituted PNP-pincer ligands is synthesized by the reduction of the corresponding monomeric molybdenum-trichloride complexes under 1 atm of molecular dinitrogen. Introduction of ferrocene as a redox-active moiety to the pyridine ring of the PNP-pincer ligand increases the catalytic activity for the formation ...

The crystal structures of two ansa-titanocene tri-fluoro-methane-sulfonate complexes bearing the Me2Si(C5Me4)2 ligand are reported, namely [di-methylbis-(η5-tetra-methyl-cyclo-penta-dien-yl)silane](tri-fluoro-methane-sulfonato-κ2O,O')titanium(III) toluene monosolvate, [Ti(CF3O3S)(C20H30Si)]·C7H8, 1, and chlorido-[di-methyl-bis-(η5-tetra-methyl-cyclo-penta-dien-yl)silane](tri-fluoro-methane-sulf...

One of the research projects is concerned with the four-membered saturated inorganic ring system called cylcodiphosphazanes, which essen ally act as monoor bidentate ligands toward transi on metals. Deriva ves of cyclodiphosphazanes containing oxygen, sulphur, phosphorous or nitrogendonor-func onali es have shown versa le coordina on behaviour, resul ng in simple mononuclear to tri-, tetraor po...

Research on "post-metallocene" polymerization catalysis ranges methodologically from fundamental mechanistic studies of polymerization reactions over catalyst design to material properties of the polyolefins prepared. A common goal of these studies is the creation of practically useful new polyolefin materials or polymerization processes. This Review gives a comprehensive overview of post-metal...

The synthesis of a series of C1-symmetric metallocene complexes rac-[1-(5,6-dialkoxy-2-methyl1-η5-indenyl)-2-(9-η5-fluorenyl)ethane]zirconium dichlorides (alkyl: n-butyl, n-hexyl, n-octyl, ndecyl) is described. These complexes are versatile catalysts in the polymerization of propylene after in situ activation with triisobutylaluminum (TIBA) and Ph3C[B(C6F5)4] in toluene and heptane solution. Al...

Olefin polymerization catalysis is a domain of major research activity. For the last decade, much of this research has been focused in the area of metallocene catalysis, which has been at the front line in driving important technology renewal in the polyolefins industry. Developments in metallocene catalysis have instigated much trade press discussion, and now emerging nonmetallocene catalyst s...