Metallocene compositions

A compound represented by the formula:

• wherein:
• M is selected from the group consisting of titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum and tungsten;
• R1 and R2 are identical or different, and are one of a hydrogen atom, a C1-C10 alkyl group, a C1-C10 alkoxy group, a C6-C10 aryl group, a C6-C10 aryloxy group, a C2-C10 alkenyl group, a C2-C4 alkenyl group, a C7-C40 arylalkyl group, a C7-C40 alkylaryl group, a C8-C40 arylalkenyl group, or a halogen atom;
• R5 and R6 are identical or different, and are one of a hydrogen atom, a halogen atom, a C1-C10 alkyl group which may be halogenated, a C6-C10 aryl group which may be halogenated, a C2-C10 alkenyl group, a C7-C40arylalkyl group, a C7-C40 alkylaryl group, a C8-C40 arylalkenyl group, a —NR215, —SR15, —OR15, —OSiR315 or —PR215 radical, wherein R15 is one of a halogen atom, a C1-C10 alkyl group, or a C6-C10 aryl group;
• R7 is
• wherein:
• R17 to R24 are as defined for R1 and R2, or two or more adjacent radicals R17 to R24, including R20 and R21, together with the atoms connecting them form one or more rings;
• M2 is carbon, silicon, germanium or tin;
• and
• the radicals R3, R4 and R10 are identical or different and have the meanings stated for R5 and R6, or two adjacent R10 radicals are joined together to form a ring.