| abstract |
A catalyst system comprisingn a) a metal complex of the formula CyLMZ p ,n wherein M is a group 4 metal Z is an anionic ligand, p is number of 1 to 2, preferably 2 Cy is a cyclopentadienyl-type ligand and, L is a ligand of the formula n nn n n n n n n n n n n n wherein each A is independently selected from the group consisting of nitrogen and phosphorus and n R 1 , R 2 , and R 4 are independently selected from the group consisting of hydrogen, unsubstituted or substituted hydrocarbyl, unsubstituted or substituted silyl and unsubstituted or substituted germyl residues, and n b) a boron containing activator, n characterized in that the molar ratio of the boron of the activator to M of the metal complex is greater than 2.5. |