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
-arylalkyl 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
1-20
hydrocarbyl group optionally containing one or more heteroatoms from groups 14-16 and optionally substituted by one or more halo atoms.
A ligand of formula (I′)
wherein
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
-arylalkyl or C
7-20
-alkylaryl;
R
2
and R
2
′ are each independently a C
1-20
hydrocarbyl radical;
R
5′
is a C
1-20
hydrocarbyl group;
R
6
, R
6′
, R
7
and R
7′
are each independently hydrogen or a C
1-20
hydrocarbyl group;
Ar and Ar′ are independently an aryl or heteroaryl group having up to 20 carbon atoms;
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 non aromatic ring with the Ar group; and
each R
4
is a C
1-20
hydrocarbyl group;
and the dotted lines represent a double bond present in between carbons 1 and 2 or 2 and 3 of the indenyl ring.
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′2C—, —R′2C—CR′2, —R′2Si—, —R′2Si—SiR′2—, —R′2Ge—, wherein each R′ is independently a hydrogen atom, C1-20-hydrocarbyl, tri(C1-20-alkyl)silyl, C6-20-aryl, C7-20-arylalkyl or C7-20-alkylaryl; R2 and R2′ are each independently a C1-20 hydrocarbyl radical optionally containing one or more heteroatoms from groups 14-16; R5′ is a C1-20 hydrocarbyl group optionally containing one or more heteroatoms from groups 14-16 and optionally substituted by one or more halo atoms.