Metal complex compounds

A process for polymerizing an olefin, diolefin or acetylenic compound comprising contacting the olefin, diolefin or acetylenic compound or mixture thereof with a monocyclopentadienyl or substituted monocyclopentadienyl metal complex containing compound corresponding to the formula:

• CpMX.sub.n.sup.+ A.sup.-
• wherein:
• Cp is a single .eta..sup.5 -cyclopentadienyl or .eta..sup.5 -substituted cyclopentadienyl group optionally covalently bonded to M through a substituent;
• M is a metal of Groups 3-10 or the Lanthanide Series of the Periodic Table bound in an .eta..sup.5 bonding mode to the cyclopentadienyl or substituted cyclopentadienyl group;
• X each occurrence independently is selected from the group consisting of hydride, halo, alkyl, aryl, silyl, germyl, aryloxy, alkoxy, amide, siloxy, neutral Lewis base ligands and combinations thereof having up to 20 non-hydrogen atoms, and optionally one X together with Cp forms a metallocycle with M;
• n is one or two depending on the valence of M;
• and
• A.sup.- is a noncoordinating, compatible anion of a Bronsted acid salt under polymerization conditions and recovering the resulting polymer.