Novel group 4b ansa-metallocene complexes with the shortest bridge: [1,1′-isopropylydene-3,3′-di-t.Bu-bis(η5-cyclopentadienyl)] Ti and Zr dichlorides
摘要:
Reaction of [1,1'-isopropylidene-3,3'-di-tert.butyl-bis(eta(5)-cyclopentadienide)] dilithium with TiCl3, followed by treatment with HCl, and ZrCl4 in various solvent mixtures in the temperature range 0-50 degrees C gives corresponding ansa-metallocene dichlorides as mixtures of the anti/syn-isomers, 1:1. The crystal and molecular structures of three of the four isomers were determined, i.e. rac(anti)-[1,1'-isopropylidene-3,3'-di-tert.butyl-bis(eta 5-cyclopentadienyl)]TiCl2, space group B2/b, rac(anti)-[1,1'-isopropylidene-3,3'-di-tert.butyl-bis(eta(5)- cyclopentadienyl)]ZrCl2), space group P2(1)2(1)2(1), and meso(syn)-1,1'-[isopropylidene-3,3'-di-tert.butyl-bis(eta(5)-cyclopentadienyl)]ZrCl2, space group P2(1)/n. (C) 1997 Elsevier Science S.A.