Heteroatom-substituted group 4 bis(indenyl)metallocenes

The synthesis, characterization and applications of heteroatom-substituted group 4 bis(indenyl)metallocene complexes is reviewed. In recent years, an increasing number of group 4 metallocenes with electronically modified cyclopentadienyl ligands have been reported with, in some cases, considerably altered catalytic properties. This microreview focuses on bis(indenyl) complexes of titanium, zirconium and hafnium that contain nitrogen, oxygen and sulfur atoms directly bonded to the five- or six-membered rings of the indenyl ligand framework. The catalytic performance is briefly reviewed, with emphasis on catalytic olefin polymerization. (C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004.