Catalytic systems made of a complex of rare earths for stereospecific polymerisation of conjugated dienes

摘要

The present invention relates to a multi-component catalytic system that can be used for the cis-1,4 stereospecific polymerization of conjugated dienes. The system is based on:(i) a rare-earth complex of Formula (II) Ln(A)₃(B)_n, Ln being a rare-earth metal, A a ligand, B a Lewis base or a solvent molecule and n a number from 0 to 3;(ii) an alkylating agent;(iii) a compound based on an aromatic ring and having at least two heteroatoms chosen from the elements O, N, S, P, and corresponding to the Formula (III):; in which the R groups each denote hydrogen, an alkyl radical optionally comprising one or more heteroatoms (N, O, P, S, Si) or one or more halogen atoms, a halogen atom, a group based on one or more heteroatoms (N, O, P, S, Si); x and y are integers from 0 to 6; D is a group having a chemical function, one of the atoms of which has a non-bonding pair; L being an atom from column 1 of the Periodic Table.