PREDICTED STRUCTURE SELECTIVITY TRENDS - PROPYLENE POLYMERIZATION WITH SUBSTITUTED RAC-(1,2-ETHYLENEBIS(ETA-5-INDENYL))ZIRCONIUM(IV) CATALYSTS

The effect of variation of substituents of a zirconium ansa-metallocene complex on the polymerization of propylene is studied with molecular mechanics. The hydrogen atoms at the different positions of the indenyl rings are systematically substituted with methyl, ethyl, isopropyl, and tert-butyl alkyl groups. We predict that substitution of hydrogen with methyl at the 4,4'-positions will increase the isotacticity of the polypropylene produced but that increasing the size of the alkyl groups in these positions does not provide an increase in isotacticity.