摘要:
The synthesis and NMR spectroscopic characterization of new ansa-metallocene dichloride complexes of the type (C13H8-PPh-C13H8)MCl2 (M = Zr (5), Hf (6)) is reported. The complexes can be activated with methylaluminoxane (MAO), and are then able to polymerize ethylene. In contrast to CR2 and SiR2 bridged derivatives, the PPh bridge increases the electron density of the system which leads to a drastic decrease in polymerization activities. (C) 1998 Elsevier Science S.A. All rights reserved.