Three new binaphthyl-bridged Schiff base complexes featuring different phenolate substituents (meta-Me, orthopara-di-Cl, orthopara-di-Br) were synthesized. H-1 and C-13 NMR analyses indicated that the cis-beta isomers are preferentially formed in any case. These complexes were tested as precatalysts for ethylene and propene polymerization comparing their behaviour to that of related titanium and zirconium complexes previously reported. The beneficial effect on polymerization activity of halogen atoms in the ortho, para positions of the phenolate rings was also demonstrated. (c) 2006 Elsevier B.V. All rights reserved.