Synthesis and performance of ansa-metallocene catalysts with substituted heterocyclic and indenyl ligands

Synthesis of new ansa-metallocene catalysts incorporating branched alkyl groups alpha to the bridgehead carbon of indenyl and thiapentalenyl ligands is reported. Me2Si(2-Me-4-Ph-Indenyl)(2)ZrCl2 and Me2Si(2,5-Me-2-3-Ph-Thiapentalenyl)(2)ZrCl2 type metallocenes with one and two isopropyl groups substituted for 2-methyl substitutents were prepared and used as procatalysts in propylene polymerizations and E/P copolymerizations. The 2-isopropyl groups influenced catalyst activity, molecular weight, and the relative amounts of microstructure errors. In contrast to procatalysts with only 2-methyl groups, polymer molecular weights increased in E/P copolymerizations with 2-isopropyl substituted complexes.