STEREOSPECIFIC METALLOCENE CATALYSTS - SCOPE AND LIMITS OF RATIONAL CATALYST DESIGN

Structure-performance relationships in the propene polymerization beha viour of a number of silicon bridged bisindenyl zirconocenes show a ra tional pattern. Prognosis of the polymerization behaviour of different type structures, however, often fails, which is demonstrated by three examples of new zirconocenes. These include two bisindenyl complexes with two-membered silicon bridges and one isospecific bridged fluoreny l cyclopentadienyl species. It is thus demonstrated that the scope of a ''rational catalyst design'' in the field of metallocene catalysts i s still limited.