Tetrahydroindenyl-Type Fused Bicyclic Zirconium Complexes: Preparation And Application To Polymer Synthesis

Metallocene complexes of Group IV metals having ansa-bridged ligands are well established highly active co-catalysts for the homo- and co-polymerisation of ?-olefins. Tetrahydroindenyl derivatives can be more effective co-catalysts than the parent unsaturated derivatives, particularly for the incorporation of co- and ter-monomers. Moreover, it appears that the hydrogenation modifies the steric and electronic properties of these metallocenes leading to a greater resistance to hydrolysis. The unsubstituted indenyl and fluorenyl ligands are directly available, whilst the normal route tetrahydroindenyl ligands is via the catalytic hydrogenation of the corresponding unsaturated indenyl complexes. We have recently reported a new synthetic method [1] to access directly these complexes, in alternative to the normal route via the catalytic hydrogenation of the corresponding unsaturated indenyl complexes.