A series of seven alkyl substituted complexes of the type (RCp)2TiCl2 (R= H, ethyl, n-propyl, iso-propyl, n-butyl, iso-amyl, ciclo-hexyl) was prepared, as well as the novel compound with R = sec-butyl, and the effects of the substituent on the polymerisation of styrene was investigated at the temperatures of 0 and 50 ºC. It was found that R = n-butyl maximises the production of syndiotactic polystyrene. Alkyl ligands with R = RCH2- are superior to those with R = RR’CH- and to the precursor Cp2TiCl2 in the production of high molecular weight syndiotactic polystyrene.
substituted titanocenes; homogeneous catalysis; syndiotactic polystyrene
