Non Flory-Schulz ethene oligomerization with titanium-based catalysts

Cationic monocyclopentadienyl (half-sandwich) titanium complexes are especially known as catalysts for the polymerization of styrene to syndiotactic polystyrene, an important engineering plastic. Recently, the representative complex [Cp*TiMe2][MeB(C6F5)3] was found to effect the (quasi-) living polymerization of propene to high molecular weight atactic polypropene. The resulting polymer displays interesting elastomeric properties. The same catalyst system in toluene solvent produces with ethene short-chain (n-butyl) branched polyethene; a polymer which shows LLDPE-like behavior (LLDPE = Linear Low Density Polyethene, which is normally manufactured by copolymerization of ethene with C4-C8 a-olefins). Half-sandwich titanium compounds thus are very interesting precursors for olefin polymerization catalysts that give access to commercially important polyolefins. Zie: Summary en samenvatting