Process for the preparation of a high molecular weight olefin polymer

A metallocene compound of the formula I ##STR13## in which M.sup.1 is a metal of group IVb, Vb or VIB of the periodic table,

• R.sup.1 and R.sup.2 are identical or different and are a hydrogen atom, A c.sub.1 -C.sub.10 -alkyl group, a C.sub.1 -C.sub.10 -alkoxy group, aC.sub.6 -C.sub.10 -aryl group, a C.sub.6 -C.sub.10 aryloxy group, a C.sub.2 -C.sub.10 -alkenyl group, a C.sub.7 -C.sub.40 -arlalukd group, a C.sub.7 -C.sub.40 -alkylarly group, a C.sub.8 -C.sub.40 -arylakenyl group or a halogen atom,
• the radicals R.sup.3 are identical or different and are a hydrogen atom, a halogen atom, A c.sub.1 -C.sub.10 -alkyl group, which can be hydrogenated a C.sub.6 -C.sub.10 -aryl group, which can be halogenaed, or a --NR.sub.2.sup.10 --SR.sup.10 --OSiR.sub.3.sup.10, --SiR.sub.3.sup.10 or --PR.sub.2.sup.10 radical, in which R.sup.10 is a halogen atom, a C.sub.1 `r a C.sub.6 -C.sub.10 -aryl group,
• R.sup.4 to R.sup.6 are identical or different and have the meaning gien for R.sup.3, with the proviso that R.sup.4 and R.sup.6 are not hydrogen,
• R.sup.7 is ##STR14## .dbd.BR.sup.11, .dbd.AlR.sup.11, --Ge--, --Sn--, --O--, --S--, .dbd.SP, .dbd.SO.sub.2 .dbd.NR.sup.11, .dbd.COm .dbd.PR.sup.11 or .dbd.P(O)R.sup.11
• in which
• R.sup.11, R.sup.12 and R.sup.13 ar identical or different and are a hydrogen atom, a halogen atom, a C.sub.1 -C.sub.10 -alkyl group, a C.sub.1 -C.sub.10 -fluoroalkyl group, a C.sub.6 -C.sub.10 -aryl grip, a C.sub.6 -C.sub.10 -fluoroaly group, a C.sub.1 -C.sub.10 -alkoxy group, a C.sub.2 -C.sub.10 -akenyl group, a C.sub.7 -C.sub.40 -arylalkyl group, a C.sub.8 -C.sub.4 alkylarly group, or R.sup.11 and R.sup.12, or R.sup.11 and R.sup.13, in each case with the atoms joining them, form a ring,
• M.sup.2 is silicon, germanium or tin,
• R.sup.8 and R.sup.9 are identical or different and have the meaning given for R.sup.11 and m and n are identical or different and are zero, 1 or 2, m plus n being zero, 1 or 2.