Metallocene compounds

A catalyst system for polymerizing at least one olefin, the catalyst system obtained by contacting:

• a metallocene compound of formula (II):
• wherein
• M is a Group 3 or 4 metal or a lanthanide or actinide element;
• X, equal to or different from each other, is hydrogen, a halogen, R, OR, OR′O, OSO2CF3, OCOR, SR, NR2, or PR2;
• R is a linear or branched, cyclic or acyclic C1-C40-alkyl, C2-C40 alkenyl, C2-C40 alkynyl, C6-C40-aryl, C7-C40-alkylaryl or C7-C40-arylalkyl, optionally comprising at least one Group 13-17 heteroatom;
• R′ is a C1-C20-alkylidene, C6-C20-arylidene, C7-C20-alkylarylidene, or C7-C20-arylalkylidene;
• L is a divalent bridging group selected from a C1-C20 alkylidene, a C3-C20 cycloalkylidene, a C6-C20 arylidene, a C7-C20 alkylarylidene, or a C7-C20 arylalkylidene, optionally comprising at least one Group 13-17 heteroatom, or L is a silylidene radical comprising up to 5 silicon atoms;
• R1 is a linear C1-C40 hydrocarbon optionally comprising at least one Group 13-17 heteroatom;
• and
• each of R4, R6, R7, R8, R9, R10 R11 and R12 is independently hydrogen or a C1-C40 hydrocarbon, optionally comprising at least one Group 13-17 heteroatom;
• at least an alumoxane or a compound capable of forming an alkylmetallocene cation;
• and
• optionally, an organo aluminum compound.