PREPARATION AND CRYSTAL-STRUCTURES OF THE COMPLEXES (ETA-5-C5H4CME2-ETA-5-C13H8)MCL2 (M = ZR, HF) AND THEIR ROLE IN THE CATALYTIC FORMATION OF SYNDIOTACTIC POLYPROPYLENE

The reactions Of MCl4 (M = Zr, Hf) with the dilithium salt of 2-cyclopentadienyl-2-fluorenylpropane in pentane solution give the complexes (eta-5-C5H4CMe2-eta-5-C13H8)MCl2. NMR and X-ray diffraction data show that there are eta-5-bonded fluorenyl groups in these complexes. When activated with methytalumoxane both complexes catalyse the stereospecific polymerization of propylene to syndiotactic polypropylene.