The binuclear salphen Ti polymerization catalyst N,N′-1,2-phenylene[(salicylideneaminato)Ti(Cp∗)Me2)]2 (2) is synthesized by reaction of salphen-H2 with Cp∗TiMe3. Mononuclear [N-(2,6-diisopropyl)phenyl(salicylideneaminato)]Ti(Cp∗)Me2 (1) serves as a control. Activation studies of 2 with cocatalyst Ph3C+B(C6F5)4 - yield the cationic polymerization-inactive complex [N,N′-1,2-phenylene(salicylideneaminato)Ti(Cp∗)]+B(C6F5)4 - (4) and polymerization-active Cp∗TiMe2 +B(C6F5)4 -. Polymerization studies comparing 2 with Cp∗TiMe3 suggest that, within the catalytic time frame, while 2 retains bimetallic character under an ethylene atmosphere, it rapidly decomposes to 4 and Cp∗TiMe2 + in the presence of 1-hexene. These monomer-dependent reorganization results highlight the importance of olefin polymerization activation mechanistic studies while providing insight for improved bimetallic catalyst design.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Organic Chemistry
- Inorganic Chemistry