SUMMARY: Ethylene homo-and copolymerization with 1-hexene were performed in the presence of diphenylmethylidene(cyclopentadienyl)(fluorenyl)zirconium dichloride (Ph 2 C(Cp)(Flu)ZrCl 2 ) derivatives activated with dimethylanilinium tetrakis(pentafluorophenyl)borate (Me 2 PhNH N B(C 6 F 5 ) 4 )/triisobutylaluminium (iBu 3 Al) or methylaluminoxane (MAO) to study the role of the substituent on activity, comonomer incorporation and molecular weight. C 1 symmetric metallocenes which have several substituents in b-position of the cyclopentadienyl ligand produce lower molecular weight copolymers than the Ph 2 C(Cp)(Flu)ZrCl 2 catalyst at 200 8C, whereas the copolymerization reactivity is significantly influenced by the volume of the substituent: the trimethylsilyl substituted derivative produces ethylene/1-hexene copolymers with a broad chemical composition distribution. Polyethylene obtained with the diphenylmethylidene(cyclopentadienyl)(indenyl)zirconium dichloride (Ph 2 C(Cp)(Ind)ZrCl 2 ) based catalyst is branched, and the molecular weight distribution and the chemical composition distribution are significantly affected by the cocatalyst. C s symmetric metallocenes which have alkyl substituents in 2,7 position of the fluorenyl ligand produce higher molecular weight copolymers than the Ph 2 C(Cp)(Flu)ZrCl 2 catalyst with equal copolymerization reactivity.

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15) Robin, M. B. Higher Excited States of Polyatomic Molecules; Academic Press: New York, 1975; Vols. 1-3. Bock, H.; Wittel, K.; Veith, M.; Wiberg, N. J. Am. Chem. Soe. 1976, 98, 109. Halevi, E. A.; Winkelhofer, G.; Meisl, M.; Janoschek, R. J. Organomet. Chem. 1985,294, 151. Experimental and calculated electronic transitions of Si,Me8 are reported in ref 5. Summary: Reaction of (q5-C5H,)(CO)LFe{P(0)YZ] (L = CO, Y = Z = OEt; L = CO, Y = OMe, 2 = NEt,; L = P(OMe)Ph,, Y = Z = Ph) with lithium diisopropylamide