New indenyl titanium catalysts for syndiospecific styrene polymerizations

A series of multi-methyl-substituted indenes as well as allylindene, n-propylindene, n-but-1-enylindene, and n-butylindene have been prepared in good yields. The substituted indenes were converted into trimethylsilyl derivatives via reactions of intermediate organolithium complexes with chlorotrimethylsilane. The corresponding titanium complexes were synthesized in excellent yields from reactions of the trimethylsilyl derivatives with TiCl4. The titanium complexes were evaluated as styrene polymerization catalysts in toluene solution when activated by methylaluminoxane. In general, catalytic activities decreased with each additional methyl substituent. Syndiospecificities were very high (90-95%). (C) 1999 Elsevier Science S.A. All rights reserved.