Activation and Polymerisation of ansa‐Zirconocene Chloroamido Complexes

Summary: Propene polymerisation was conducted with three ansa‐zirconocene complexed: Me2Si(2‐Me‐4‐PhInd)2ZrCl2 (A), Me2Si(2‐Me‐4‐PhInd)2ZrClNMe2 (B) and Me2Si(2‐Me‐4‐PhInd)2ZrClNEt2 (C). Methylalumoxane (MAO) or [HNPhMe2][B(C6F5)4] was used as cocatalyst. The influence of cocatalysts and triisobutylaluminum (TIBA) on polymerisation activity, molecular weight and polymer microstructure was studied. Furthermore, the alkylation and activation of the complexes were examined using UV/VIS spectroscopy. Complex A was the most active in polymerisation, but polymers produced by B and C had in general higher molecular weights. Replacing MAO partially by TIBA increased the molecular weight and prevented catalyst deactivation. According to the UV/VIS measurements, all complexes have low reactivity towards TMA and TIBA. Similar cationic species were formed of all three studied zirconocenes in the reaction with MAO. Additional TIBA did not affect the type of active species formed in the reaction of zirconocene and MAO, but increased the activity of B and C. UV/VIS spectrum of complex A with MAO and with a MAO/TIBA mixture. image UV/VIS spectrum of complex A with MAO and with a MAO/TIBA mixture.