The new ansa-complexes (R-Ph)(2)C(Cp)(Ind)MCl2 (R = CF3, F, CI; M = Ti, Zr or Hf) were synthesized from the reaction of dilithium salt of the corresponding ligands with appropriate group 4 metal halides. They were tested for ethylene homopolymerization and copolymerization in the presence of methylaluminoxane (MAO) at various ethylene pressures and temperatures. In the case of zirconocenes, complexes 2 (R = CF3) and 8 (R = Cl) demonstrated much higher catalytic activity than complexes 10 (Ph2C(Cp)(Ind)ZrCl2) and 5 (R = F) in ethylene polymerization. The same trend was observed in titanocenes and hafnocenes. The electronic and geometric effects of substituents at the phenyl group on the polymerization activity were easily noticed. For the ethylene/1-hexene or 1-octene copolymerization, 2 also showed the highest catalytic activity, and the copolymers from complex 8 possessed the highest 1-hexene and 1-octene contents. (c) 2006 Elsevier B.V. All rights reserved.