A catalyst comprising (i) 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 linear C 1-10 hydrocarbyl; R 5 and R 5′ are each independently hydrogen or a C1-20 hydrocarbyl group; R 6 and R 6′ are each independently hydrogen or a C1-20 hydrocarbyl group; R 7 is hydrogen or a C1-20 hydrocarbyl group or is ZR 3 ; Z is O or S, preferably O; R 3 is a C1-10 hydrocarbyl group; Ar is an aryl or heteroaryl group having up to 20 carbon atoms optionally substituted by one or more groups R 8 ; Ar′ is an aryl or heteroaryl group having up to 20 carbon atoms optionally substituted by one or more groups R 8′ ; and R 8 and R 8′ are each independently is a C1-20 hydrocarbyl group; with the proviso that at least one of R 6 or R 7 is not H; and (ii) a cocatalyst comprising a compound of a group 13 metal, e.g. boron.
1. A catalyst comprising
(i) 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 linear C 1-10 hydrocarbyl;
R 5 and R 5′ are each independently hydrogen or a C1-20 hydrocarbyl group;
R 6 and R 6′ are each independently hydrogen or a C1-20 hydrocarbyl group;
R 7 is hydrogen or a C1-20 hydrocarbyl group or is ZR 3 ;
Z is O or S;
R 3 is a C1-10 hydrocarbyl group;
Ar is an aryl or heteroaryl group having up to 20 carbon atoms optionally substituted by one or more groups R 8 ;
Ar′ is an aryl or heteroaryl group having up to 20 carbon atoms optionally substituted by one or more groups R 8′ ; and
R 8 and R 8′ are each independently a C1-20 hydrocarbyl group;
with the proviso that at least one of R 6 and R 7 is not H; and
(ii) a cocatalyst comprising a compound of a group 13 metal.
2. A catalyst as claimed in claim 1 wherein the complex is a racemic anti isomer.
3. A catalyst as claimed in claim 1 wherein R 2 is linear C1-6 alkyl.
4. A catalyst as claimed in claim 1 wherein one of R 6 and R 7 is H.
5. A catalyst as claimed in claim 1 wherein R 5 is H and R 5′ is H.
6. A catalyst as claimed in claim 1 wherein said complex is of formula (II)
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 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 and C7-C20-alkylaryl;
R 2 and R 2′ are each independently linear C1-4 alkyl;
R 5 and R 5′ are each independently hydrogen or an aliphatic C1-10 hydrocarbyl group;
R 6 and R 6′ are each independently hydrogen or an aliphatic C1-10 hydrocarbyl group;
R 7 is hydrogen or an aliphatic C1-10 hydrocarbyl group or is ZR 3 ;
Z is O or S;
R 3 is a C1-10 alkyl group;
R 8 and R 8′ are each independently an aliphatic C1-20 hydrocarbyl group;
n is 0, 1, 2 or 3; and
n′ is 0, 1, 2 or 3;
with the proviso that one of R 6 and R 7 is not H.
7. A catalyst as claimed in claim 1 wherein said complex is 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—, —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 and C7-C20-alkylaryl;
R 5 and R 5′ are hydrogen or a C1-10 alkyl group;
R 6 and R 6′ are hydrogen or a C1-10 alkyl group;
R 7 is hydrogen or C1-10 alkyl group or is OR 3 ;
R 3 is a C1-10 alkyl group;
n is 1 to 3;
n′ is 1 to 3;
and R 8 and R 8′ are an aliphatic C1-10 hydrocarbyl group;
with the proviso that one of R 6 and R 7 is not H.
8. A catalyst as claimed in claim 1 wherein said complex is of formula (IV):
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 Si—, —R′ 2 Si—SiR′ 2 —, —R′ 2 Ge—, wherein each R′ is independently a hydrogen atom, C1-C20-hydrocarbyl, tri(C1-C20-alkyl)silyl, C6-C20-aryl, C7-C20-arylalkyl and C7-C20-alkylaryl;
R 6 is hydrogen or a C1-10 alkyl group;
R 6′ is hydrogen or a C1-10 alkyl group;
R 7 is hydrogen or C1-10 alkyl group or is OR 3 ;
R 3 is a C1-10 alkyl group;
n is 1 to 3;
n′ is 1 to 3;
and R 8 and R 8′ are a C1-10 alkyl group;
with the proviso that one of R 6 and R 7 is not H.
9. A catalyst as claimed in claim 1 wherein said complex is of formula (V)
wherein L, M and X are as hereinbefore defined;
R 6 is hydrogen or a C1-6 alkyl group;
R 6′ is hydrogen or a C1-6 alkyl group;
R 7 is hydrogen or C1-6 alkyl group or is OR 3 ;
R 3 is a C1-6 alkyl group;
n′ is 1 to 3;
and R 8 and R 8′ are a C1-10 alkyl;
with the proviso that one of R 6 and R 7 is not H.
10. A catalyst as claimed in claim 1 wherein said cocatalyst is MAO.
11. A catalyst as claimed in claim 1 in solid form.
12. A catalyst as claimed in claim 1 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 1 comprising obtaining a complex of formula (I)(i) and a cocatalyst (ii);
forming a liquid/liquid emulsion system, which comprises a solution of catalyst components (i) and (ii) dispersed in a solvent so as to form dispersed droplets, and solidifying said dispersed droplets to form solid particles.
14. A process for the polymerisation of at least one olefin comprising polymerizing the at least one olefin in the presence of the catalyst of claim 1 .