[l,8-C,0H6(NSi'BuMe2)2]TiBr2 (4) has been prepared from dilithio salts [l,8-CinH6(NR),]Li, (2) and TiBr4 in Et2O. This complex showed significant catalytic activity for ethylene polymerization in the presence of a cocatalyst, and the activity is the same as those obtained by using chloride analogues such as [1,8-C10H6(NR)2] TiCl2 (3: R = SiMe3 Si'BuMe2 Si'Pr,). The effective cocatalyst was, however, different between the chloride and the bromide complexes. [ArNCH2CH2CH2NAr]TiCl2 (5, Ar = 2,6-iPr2C6H3), which has been known as an effective catalyst for polymerization of 1-hexene, showed lower activity under the same conditions. The broad molecular weight distributions (Mw/Mn for the resultant polymer can be attributed to the scission of titanium-nitrogen bond by cocatalyst, because the narrow MJMnvalue (1.8) was observed if the polymerization was stopped at the initial stage (2 min) under the same reaction conditions.
ASJC Scopus subject areas
- Condensed Matter Physics
- Physical and Theoretical Chemistry
- Surfaces, Coatings and Films
- Materials Chemistry