Ethylene polymerization and ethylene/styrene copolymerization by [Me2Si(indenyl)(NtBu)]TiX2 (X=Cl, Me) complexes-cocatalyst systems

Effects of a cocatalyst for ethylene homopolymerization as well as for ethylene/styrene copolymerization using [Me2Si(indenyl)(N-tert-Bu)]TiX2 [X=Cl(1a), Me(1b)] have been explored. [Me2Si(C5Me4)(NR)]TiCl2 [R=N-tert-Bu (2), cyclohexyl (3)] have been chosen as the references. 1-methyl isobutyl aluminoxane (MMAO) or MMAO/B(C6F5)(3) catalysts exhibited low catalytic activities for both ethylene polymerization and ethylene/styrene copolymerization, and a significant amount of polyethylene was by-produced in the ethylene/styrene copolymerization. The observed difference in the copolymerization behavior with 1 from previous reports by Okuda and Campbell would be due to the cocatalyst used that afforded several catalytically-active species in this catalytic reaction. The microstructures of the resultant poly (ethylene-co-styrene)s were affected by the substituent on both cyclopentadienyl and amide ligands.