Patent ID: 7199075

Claim:
A catalyst composition comprising at least one nickel complex corresponding to general formula L 2 NiX 2 in which: L is a bidentate chelating ligand that contains a nitrogen-containing heterocyclic compound of general formula: Ha-C(OH)RR′ in which: R and R′, identical or different, each represent a monovalent radical that contains up to 12 carbon atoms wherein such monovalent radical is alkyl, aryl, aralkyl, alkaryl, cycloalkyl or a substituted aryl radical, or a perfluoroalkyl radical, Ha represents a radical wherein said radical is an unsubstituted or substituted pyridine, oxazoline or an imidazole cycle; and X is an alkyl radical, a halide anion, acetylacetonate or a carboxylate optionally substituted by at least one halogen, said catalyst composition further comprising at least one hydrocarbylaluminium compound which is at least one tris(hydrocarbyl)aluminum compound or at least one chlorinated or brominated hydrocarbylaluminum compound or at least one aluminoxane.