ORTHO-METALLATED HAFNIUM COMPLEXES OF IMIDAZOLE LIGANDS

1 . A metal complex corresponding to the formula:

wherein, X independently each occurrence is an anionic ligand, or two X groups together form a dianionic ligand group, or a neutral diene;

T is a cycloaliphatic or aromatic group containing one or more rings;

R 1 independently each occurrence is hydrogen, halogen, or a univalent, polyatomic anionic ligand, or two or more R 1 groups are joined together thereby forming a polyvalent fused ring system;

R 2 independently each occurrence is hydrogen, halogen, or a univalent, polyatomic anionic ligand, or two or more R 2 groups are joined together thereby forming a polyvalent fused ring system; and

R 4 is hydrogen, alkyl, aryl, aralkyl, trihydrocarbylsilyl, or trihydrocarbylsilylmethyl of from 1 to 20 carbons.

2 . A metal complex according to claim 1 wherein T is a polycyclic, fused ring, divalent aromatic group, R 4 is C 1-4 alkyl, and X each occurrence is C 1-20 alkyl, cycloalkyl or aralkyl.

3 . A metal complex according to claim 1 corresponding to the formula:

wherein

R 1 independently each occurrence is a C 3-12 alkyl group wherein the carbon attached to the phenyl ring is secondary or tertiary substituted, preferably each R 1 is isopropyl;

R 2 independently each occurrence is hydrogen or a C 1-12 alkyl group;

R 3 is hydrogen, halo or R 1 ;

R 4 is C 1-4 alkyl; and

X and T are as previously defined for compounds of formula (I).

4 . A metal complex according to claim 2 corresponding to the formula:

wherein:

R 1 independently each occurrence is a C 3-12 alkyl group wherein the carbon attached to the phenyl ring is secondary or tertiary substituted;

R 2 independently each occurrence is hydrogen or a C 1-2 alkyl group;

R 4 is methyl or isopropyl;

R 5 is hydrogen or C 1-6 alkyl;

R 6 is hydrogen, C 1-6 alkyl or cycloalkyl, or two adjacent R 6 groups together form a fused aromatic ring;

T′ is oxygen, sulfur, or aC 1-20 hydrocarbyl-substituted nitrogen or phosphorus group,

T″ is nitrogen or phosphorus;

X is methyl or benzyl.

5 . A metal complex according to claim 1 corresponding to the formula:

wherein

R 1 independently each occurrence is isopropyl;

R 2 independently each occurrence is hydrogen or a C 1-12 alkyl group;

R 4 is C 1 — alkyl;

R 6 is hydrogen, C 1-6 alkyl or cycloalkyl; and

X independently each occurrence is methyl or benzyl.

6 . The metal complex according to claim 1 selected from the group consisting of

hafnium, [N-[2,6-bis(1-methylethyl)phenyl]-α-[2,4,6-tri(1-methylethyl)phenyl)-5-(2-ethylbenzofuran-3-yl-κ-C 4 )-2-(N′-methyl)imidazol-2-yl)methanaminato (2-)-κN 1 ,κN 2 ]di(methyl),

hafnium, [N-[2,6-bis(1-methylethyl)phenyl]-α-[2,6-di(1-methylethyl)phenyl]-5-(2-ethylbenzofuran-3-yl-κ-C 4 )-2-(N′-methyl)imidazol-2-yl)methanaminato (2-)-κN 1 , N 2 ]di(methyl),

hafnium, [N-[2,6-bis(1-methylethyl)phenyl]-α-[2,4,6-tri(1-methylethyl)phenyl]-5-(carbazol-1-yl-κ-C 2 )-2-(N′-methyl)imidazol-2-yl)methanaminato (2-)-κN 1 ,κN 2 ]di(methyl),

hafnium, [N-[2,6-bis(1-methylethyl)phenyl]-α-[2,4,6-tri(1-methylethyl)phenyl]-5-(2-ethylbenzofuran-3-yl-κ-C 4 )-2-(N′-methyl)imidazol-2-yl)methanaminato (2-)-κN 1 ,κN 2 ]di(benzyl),

hafnium, [N-[2,6-bis(1-methylethyl)phenyl]-α-[2,6-di(1-methylethyl)phenyl]-5-(2-ethylbenzofuran-3-yl-κ-C 4 )-2-(N′-methyl)imidazol-2-yl)methanaminato (2-)-κN 1 ,κN 2 ]di(benzyl),

hafnium, [N-[2,6-bis(1-methylethyl)phenyl]-α-[2,4,6-tri(1-methylethyl)phenyl]-5-(carbazol-1-yl-κ-C 2 )-2-(N′-methyl)imidazol-2-yl)methanaminato (2-)-κN 1 ,κN 2 ]di(benzyl),

hafnium, [N-[2,6-bis(1-methylethyl)phenyl]-α-[2,6-di(1-methylethyl)phenyl]-5-(carbazol-1-yl-κ-C 2 )-2-(N′-methyl)imidazol-2-yl)methanaminato (2-)-κN 1 ,κN 2 ]di(methyl), or a mixture thereof.

7 . A catalyst composition suitable for use in the coordination polymerization of an olefin comprising a metal complex according to any one of claims 1 - 6 and an activating cocatalyst.

8 . The catalyst composition according to claim 7 wherein the activating cocatalyst is a Lewis acid.

9 . The catalyst composition according to claim 8 wherein the Lewis acid is methylalumoxane or modified methylalumoxane.

10 . A catalyst composition according to claim 7 additionally comprising a support.

11 . A catalyst composition according to claim 10 wherein the support is a particulated compound selected from the oxides, sulfides, nitrides or carbides of a Group 13 or 14 metal or metalloid.

12 . A catalyst composition according to claim 11 wherein the support is silica containing methylalumoxane having the metal complex deposited on the surface thereof.

13 . An addition polymerization process comprising contacting one or more olefin monomers under polymerization conditions with a catalyst composition according to claim 7 .

14 . A process according to claim 13 which is a gas-phase polymerization process.

15 . A process according to claim 13 which is a slurry polymerization process.