Triptycene as a scaffold in metallocene catalyzed olefin polymerization

Abstract

A set of metallocene olefin polymerization catalysts bearing triptycene moieties in either position 4–5 (complexes Ty1–Ty5) or in position 5–6 (complexes Ty6–Ty8) of the basic dimethylsilyl-bridged bis(indenyl) system has been tested in propene polymerization and in ethene/1-hexene copolymerization. Comparison of the results with QSPR (quantitative structure–property relationship) predictions not parametrized for these exotic ligand variations demonstrates that trends can still be identified by extrapolation. Interestingly, Ty7, upon suitable activation, provides a highly isotactic polypropylene with an exceptional amount of 2,1 regio-errors (8%). The previously developed QSPR type models successfully predicted the low regioselectivity of this catalyst, despite the fact that the catalyst structure differs significantly from the benchmark set.