Heteroatom-Substituted Constrained-Geometry Complexes. Dramatic Substituent Effect on Catalyst Efficiency and Polymer Molecular Weight

Abstract

The new constrained-geometry complexes (CGC) [(η 5 -C 9 H 5 X)(SiMe 2 -t-Bu)TiR 2 (X = 2-OEt ( 1a,b ), 2-NMe 2 ( 2a,b ), 3-OMe ( 3a,b ), 3-NC 4 H 4 ( 4a,b ); R = Cl, Me) have been synthesized with alkoxy and amino substituents attached to a second and third indenyl position. Four of the new complexes ( 1a − 4a ) have been characterized by single-crystal X-ray analysis. An ethylene/1-octene copolymerization study revealed an enormous substituent effect, both on the catalysts' activity and the molecular weight of produced polymers. The 3-amino-substituted complex 4b exhibits the highest catalytic activity and forms the highest molecular weight ethylene/octene copolymers that have ever been reported for this class of catalysts.