Control of the Molecular Weight of Polyethene in Syntheses with Bis(ylide)nickel Catalysts

Polyethenes in almost all molecular weight ranges —from polyethene waxes and hard waxes through high-density polyethene to ultrahigh molecular weight polyethene -are accessible with the aid of novel, very active bis(ylide)nickel(0) catalysts. The catalysts are prepared from bis(cyclooctadiene)nickel(0), the carbonyl-stabilized ylide ligands 1-3, and a non-stabilized ylide.