Preparation and crystal structures of the complexes (η5-C5H4CMe2η5-C13H8) MCl2 (M Zr, Hf) and their role in the catalytic formation of syndiotactic polypropylene
摘要:
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.