Patent ID: 7544749

Claim:
A process comprising polymerizing propylene in the presence of a catalyst system prepared by a process comprising reacting at least one transition metal compound of the formula (Ia) or (Ia*): where M is zirconium or hafnium; Z are identical or different and are each halogen, hydrogen, C 1 -C 10 -alkyl, C 6 -C 14 -aryl, alkylaryl or arylalkyl having from 1 to 4 carbon atoms in the alkyl part and from 6 to 10 carbon atoms in the aryl part; n1 and n2 are each 1; R 1 and R 2 are identical or different and are each a C 1 -C 40 radical, or R 1 and R 2 together with the atoms connecting them form a cyclic or polycyclic ring system which may contain one or more, identical or different heteroatoms selected from the group consisting of the elements N, O, P, S and Si in place of carbon atoms in the ring system; R 5 and R 6 are identical and are each hydrogen or a C 1 -C 40 radical; R 10 , R 11 are identical or different and are each hydrogen, t-butyl or phenyl; R 12 are identical or different and are each t-butyl or phenyl; and R 13 are identical or different and are each hydrogen or a C 1 -C 40 radical, or two adjacent radicals R 10 and R 11 , together with the two connecting carbon atoms may form a cyclic ring system, with at least one cation-forming compound, wherein an isotactic propylene polymer is formed having an isotacticity determined by pentad analysis of the 13 C-NMR spectrum of greater than 98%.