Catalysts

摘要

An asymmetric 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, C1-C20-alkyl, tri(C1-C20-alkyl)silyl, C6-C20-aryl, C7-C20-arylalkyl or C7-C20-alkylaryl;
R 2 and R 2' are each independently a C 1 -C 20 hydrocarbyl radical;
R 5' is a C 1-20 hydrocarbyl group;
R 5 is hydrogen, or a C 1-20 hydrocarbyl group;
R 6 is a non tertiary C 1-10 alkyl group or C6-10-aryl group or C7-10 arylalkyl group or ZR 3 ;
R 6' is a tertiary C 4-20 alkyl group;
R 3 is a C1-20 hydrocarbyl group optionally substituted with halo;
Ar is an aryl or heteroaryl group having up to 20 carbon atoms optionally substituted by one or more groups R 1 ;
Ar' is an aryl or heteroaryl group having up to 20 carbon atoms optionally substituted by one or more groups R 1 ;
each R 1 is a C 1-20 hydrocarbyl group or two R 1 groups on adjacent carbon atoms taken together can form a fused 5 or 6 membered ring with the Ar group, said ring being itself optionally substituted with one or more groups R 4 ; and
each R 4 is a C 1-20 hydrocarbyl group.