Abstract
Two silyl substituted unbridged bis(fluorenyl) complexes of zirconium and hafnium were prepared and characterized. The influence of the tolyldimethylsilyl substituent in the 9-position of the fluorenyl ring did not support the catalytic activity of these complexes for ethylene polymerization after activation with methylaluminoxane (MAO). Obviously, the monomer ethylene induces the ring slippage behaviour of these ligands from eta(5)->eta(3)->eta(1) decomposing the catalyst.