Polymerizable group 4 ansa-cyclopentadienyl-amido catalysts for the copolymerization of ethylene with 1-octene

A styrene unit has been successfully incorporated into the half metallocene constrained-geometry framework as [(η5-C5Me4)SiMe2(η1-NC6H4CHdouble bond; length as m-dashCH2)]MX2 (M = Ti, X = NMe2, 6a; M = Zr, X = NMe2, 6b; M = Ti, X = Cl, 7a; M = Zr, X = Cl, 7b). These complexes have been characterized with 1H NMR, 13C NMR spectroscopy together with single crystal X-ray diffraction studies of 6a and 6b. A polystyrene-immobilized constrained-geometry catalyst 8 was formed by the radical copolymerization of 7a with styrene using AIBN as the initiator. The complexes 6a, 6b, 7a and 8 gave active homogeneous catalysts for the copolymerization of ethylene with 1-octene when treated with excess methylalumoxane (MAO). The polymerization results showed that 7a was highly active and effective for the incorporation of comonomer 1-octene whereas the zirconium complex 6b and the immobilized catalyst 8 yield low activities and low incorporations of 1-octene in the products with broad molecular weight distributions.