CH-Aktivierungsreaktionen an unverbrückten und verbrückten Zirconocenkomplexen zur Darstellung von Metallacyclen und deren Verwendung in der katalytischen Ethylenpolymerisation

The reaction of phenylalkyl substituted zirconocenedichloride complexes with two equivalents of n-butyllithium gives metallacyclic zirconocene complexes. In this reaction aromatic CH bonds can be activated in unbridged and bridged metallocenedichloride complexes even if the corresponding phenyl rings contain halogen substituents such as fluorine or chlorine. After the activation with methylalumoxane (MAO), all the metallocene complexes prove as attractive catalysts for ethylene polymerization reactions. Because of their Lewis basicity the halogen substituents fluorine or chlorine have a strong influence on the molecular weights of the produced polyethylenes. Metallocene complexes with chloro substituents in the ortho positions of the phenyl rings produce bimodal polyethylenes.