A compound represented by the formula: ##STR00001## where: M is a transition metal selected from group 4 of the periodic table; each R.sup.1 is independently selected from the group consisting of hydrogen, hydrocarbyl, substituted hydrocarbyl and functional group, and any two R.sup.1 groups may be linked, provided that if the two R.sup.1 groups are linked, then they do not form a butadiene group when M is Zr; R.sup.3 is carbon or silicon; R.sup.4 is hydrogen, hydrocarbyl, substituted hydrocarbyl or a functional group; R.sup.5 is hydrogen, hydrocarbyl, substituted hydrocarbyl or a functional group, R.sup.4 and R.sup.5 may be bound together to form a ring; R.sup.6 is carbon or silicon; each R.sup.7 is hydrogen; each R.sup.8 is independently selected from the group consisting of hydrogen, methyl, ethyl, propyl, butyl, pentyl, hexyl and the isomers thereof; R.sup.10 is -M.sup.2(R.sup.16).sub.h-- where M.sup.2 is B, Al, N, P, Si or Ge, h is 1 or 2; each R.sup.9, R.sup.11, R.sup.13 and R.sup.14 and R.sup.16 is hydrogen, hydrocarbyl, substituted hydrocarbyl or a functional group, and two R.sup.16 groups may be linked together to form a ring; each R.sup.12 and R.sup.15 is carbon or silicon; and a, b, c, d, e, f, and g are independently 0, 1, or 2.