Borohydride metallocene complex of a lanthanide, catalytic system including said complex, polymerization method using same and ethylene/butadiene copolymer obtained using said method

摘要

A borohydride metallocene complex of a lanthanide, its process of preparation, a catalytic system incorporating it, a process for the copolymerization of olefins employing this catalytic system and an ethylene/butadiene copolymer obtained by this process, the butadiene units of which comprise 1,2-cyclohexane or 1,2- and 1,4-cyclohexane links. This complex corresponds to one or other of the following formulae A and B:; where, in the formula A, two ligand molecules Cp₁ and Cp₂, each composed of a fluorenyl group, are connected to the lanthanide Ln, such as Nd, and where, in the formula B, a ligand molecule, composed of two fluorenyl groups Cp₁ and Cp₂ which are connected to one another via a bridge P of formula MR₁R₂, where M is an element from group IVa, such as Si, and where R₁ and R₂, which are identical or different, represent an alkyl group comprising from 1 to 20 carbon atoms, is connected to the lanthanide Ln, where L represents an alkali metal, such as Li, where N represents a molecule of a complexing solvent, such as THF, where x is an integral or non-integral number greater than 0 and where p is an integer equal to or greater than 1.