| abstract |
A racemic complex of formula (I), wherein ∙ M is zirconium or hafnium; ∙ each X is a sigma ligand; ∙ L is a divalent bridge selected from -R' 2 C-, -R' 2 C-CR' 2 , -R' 2 Si-, - R' 2 Si-SiR' 2 -, -R' 2 Ge-, wherein each R' is independently a hydrogen atom, C 1-20 -hydrocarbyl, tri(C 1-20 -alkyl)silyl, C 6-20 -aryl, C 7-20 -ary- lalkyl or C 7-20 -alkylaryl; ∙ R 2 and R 2 ' are each independently a C 1-20 hydrocarbyl radical optionally containing one or more heteroatoms from groups 14-16; ∙ R 5 ' is a C 1-2 n 0 hydrocarbyl group optionally containing one or more heteroatoms from groups 14-16 and optionally substituted by one or more halo atoms. |