Patent ID: 7547654

Claim:
A catalytic system for obtaining a copolymer of a conjugated diene and at least one monoolefin, which comprises: (i) an organometallic complex represented by the following generic formula: {[P(Cp)(Fl)]Ln(X)(L) x } p (1) Ln represents a lanthanide atom of an atomic number from 57 to 71, to which is attached a ligand molecule comprising cyclopentadienyl Cp and fluorenyl Fl groups which are each independently substituted or unsubstituted and linked to one another by a bridge P of the formula MR 1 R 2 , where M is an element from column IVa of Mendeleev's periodic table and where R 1 and R 2 , which may be identical or different, each represent alkyl groups having from 1 to 20 carbon atoms or cycloalkyl or phenyl groups having from 6 to 20 carbon atoms, X represents a halogen atom, L comprises an optional complexing molecule and optionally a substantially less complexing molecule, p is a natural integer greater than or equal to 1 and x is greater than or equal to 0, and (ii) a co-catalyst selected from the group consisting of alkylmagnesiums, alkyllithiums, alkylaluminums, Grignard reagents and mixtures of these constituents.