| abstract |
The present invention relates to a method for preparing alpha -olefins homopolymers or copolymers that involves reacting the starting monomer or monomers in the presence of one or more transition metal compounds of the general formula (I) and in the presence of a cocatalyst consisting of a potent neutral Lewis acid, of an ionic compound having a cation consisting of a Lewis acid or of an ionic compound having a Brönsted acid in the form of a cation. In the formula (I), the substituents and indices are as follow: R<1> and R<2> are C4-C16 heteroaryl or C6-C16 aryl with halogeno, nitro, cyano, sulfonato or trihalogenmethyl substituents in both ortho-positions relative to the binding site between aryl and heteroaryl and N<a> and N<b>; R<3> and R<4> are hydrogen, C1-C10 alkyl, C3-C10 cycloalkyl, C6-C16 aryl, alkylaryl with 1 to 10 carbon atoms in the alkyl portion and 6 to 14 carbon atoms in the aryl portion or Si(R<8>)3; R<8> is C1-C10 alkyl, C3-C10 cycloalkyl, C6-C16 aryl, alkylaryl with 1 to 10 carbon atoms in the alkyl portion and 6 to 14 carbon atoms in the aryl portion; R<5>, R<6> and R<7> are hydrogen, C1-C10 alkyl, C3-C10 cycloalkyl, C6-C16 aryl, alkylaryl with 1 to 10 carbon atoms in the alkyl portion and 6 to 14 carbon atoms in the aryl portion, Si(R<8>)3 or functional groups selected among the elements from the groups IVA to VIIA of the classification table or R<5> and R<6> and/or R<6> and R<7> form together a ringed five-, six- or seven-membered aliphatic or aromatic substituted or non-substituted carbon or hetero cycle; M is Fe, Ru, Co or Rh;; T and Q are neutral or monoanionic monodentate ligands; A is a non-coordinating or hardly coordinating anion; m and p are 0, 1, 2 or 3; and q and n are 1, 2 or 3. |