No Polymerization with Metallocenes in Water?-A Prejudice is Refuted.

Water-sensitive catalysts work in water! Metallocene catalysts that normally have to be handled under the strict exclusion of air and moisture, for example [TiCp*(OMe)3 ] (1, Cp*=pentamethylcyclopentadienyl), are successfully employed in the aqueous emulsion polymerization of styrene to syndiotactic polystyrene. The catalyst is encapsulated inside the monomer droplets and thus protected against attack by water.