Synthesis and characterization of ethylene-bridged 1-tert-butyldimethylsiloxy-substituted bis(indenyl) and bis(tetrahydroindenyl)zirconium dichlorides

The synthesis and characterization of three siloxy-substituted zirconocene complexes rac- and meso-ethylenebis[1-(tert-butyldimethyl siloxy)indenyl]zirconium dichlorides (3a,3b) and rac-ethylenebis[1-(tert-butyldimethylsiloxy)-4,5,6,7-tetrahydroindenyl]zirconium dichloride (4) are reported. The molecular structures of 3b and 4 have been determined and reveal that 3b crystallizes in a chiral staggered meso-conformation, whereas 4 adopts the expected C-2 symmetric bent metallocene structure with indenyl-forward conformation of the ligand backbone. In both complexes 3b and 4 the intramolecular oxygen-chlorine distances (3.15-3.30 Angstrom) are close to the sum of their van der Waals radii (3.20 Angstrom). (C) 1998 Elsevier Science S.A. All rights reserved.