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; Z is O or S; 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.
1. 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 the group consisting of —R′ 2 C—, —R′ 2 C—CR′ 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 and 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 ;
Z is O or S;
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.
2. A complex as claimed in claim 1 being a racemic anti isomer.
3. A complex as claimed in claim 1 wherein Ar and Ar′ are different.
4. A complex as claimed in claim 1 wherein R 2 and R 2′ are methyl.
5. A complex as claimed in claim 1 wherein R 5 is H and/or wherein R 5′ is methoxy.
6. A complex as claimed in claim 1 wherein R 6 is methyl and/or R 6′ is tBu.
7. A complex as claimed in claim 1 being of formula (II):
wherein
M is zirconium or hafnium;
each X is independently a hydrogen atom, a halogen atom, C 1-6 alkoxy group, C 1-6 alkyl, phenyl or benzyl group;
L is a divalent bridge selected from the group consisting of —R′ 2 C—, —R′ 2 C—CR′ 2 —, —R′ 2 Ge—, wherein each R′ is independently a hydrogen atom, C 1-20 alkyl, C 3-10 cycloalkyl, C 6-20 -aryl, C 7-20 arylalkyl and C 7-20 alkylaryl;
R 2 and R 2 ′ are each independently a C 1 -C 10 alkyl radical;
R 5′ is a C 1-6 alkyl group;
R 5 is hydrogen, or a C 1-10 alkyl group;
R 6 is a non tertiary C 1-6 alkyl, C6-10 aryl group or C7-10 arylalkyl group;
R 6′ is a tertiary C 4-10 alkyl group;
each n is independently 0 to 3;
and each R 1 is independently a C 1-10 alkyl group.
8. A complex as claimed in claim 1 of formula (III):
wherein
M is zirconium or hafnium;
each X is independently a hydrogen atom, a halogen atom, C 1-6 alkoxy group, C 1-6 alkyl, phenyl or benzyl group;
L is a divalent bridge selected from the group consisting of —R′ 2 C— or —R′ 2 Si— wherein each R′ is independently a hydrogen atom, C 1-20 alkyl and C 3-10 cycloalkyl;
R 2 and R 2 ′ are each independently a C 1-6 alkyl radical;
R 5′ is a C 1-6 alkyl group;
R 6 is a non tertiary C 1-6 alkyl;
R 6′ is a tertiary C 4-8 alkyl group;
each n is independently 0 to 3;
and each R 1 is independently a C 1-10 alkyl group.
9. A complex as claimed in claim 1 of formula (IV):
M is zirconium or hafnium;
each X is independently a hydrogen atom, a halogen atom, C 1-6 -alkoxy group, C 1-6 -alkyl, phenyl or benzyl group;
L is a divalent bridge selected from the group consisting of —R′ 2 C— or —R′ 2 Si— wherein each R′ is independently a hydrogen atom, C 1-20 alkyl and C 3-10 cycloalkyl;
R 5′ is a C 1-6 alkyl group;
R 6 is a C 1-3 alkyl;
R 6′ is a tertiary C 4-8 alkyl group;
each n is independently 0 to 2;
and each R 1 is independently a C 3-8 alkyl group.
10. A complex as claimed in claim 1 of formula (V):
wherein each X is independently a hydrogen atom, a halogen atom, C 1-6 -alkoxy group, C 1-6 -alkyl, phenyl or benzyl group;
L is -Me 2 Si—;
R 5 is a C 1-6 alkyl group;
R 6 is a C 1-3 alkyl;
n′ is 1 to 2;
n is 0 to 2;
and each R 1 is independently a C 3-8 alkyl group.
11. A catalyst comprising (i) an asymmetric complex of formula (I) as claimed in claim 1
and (ii) a cocatalyst comprising a compound of a group 13 metal.
12. A catalyst as claimed in claim 11 obtained by a process in which
(a) a liquid/liquid emulsion system is formed, said liquid/liquid emulsion system comprising a solution of the catalyst components (i) and (ii) dispersed in a solvent so as to form dispersed droplets; and
(b) solid particles are formed by solidifying said dispersed droplets.
13. A process for the manufacture of a catalyst as claimed in claim 11 comprising contacting a complex of formula (I) and a cocatalyst as hereinbefore described;
forming a liquid/liquid emulsion system, which comprises a solution of catalyst components (i) and (ii) dispersed in a solvent, and solidifying said dispersed droplets to form solid particles.
14. A process for the polymerisation of at least one olefin comprising reacting said at least one olefin with a catalyst as claimed in claim 11 .