Synthesis and reactivity of trimethylsilyl substituted mono(cyclopentadienyl)titanium alkyl complexes

Sassmannshausen, J. and Baumgartner, J. (2009) Synthesis and reactivity of trimethylsilyl substituted mono(cyclopentadienyl)titanium alkyl complexes. Kinetics and Catalysis, 50 (5). pp. 676-683. ISSN 0023-1584

Abstract

The preparation of a series of titanium half-sandwich compounds [Ti(η5-C5H5−x (SiMe3) x R3] (x = 1-3, R = Cl, Me) and their reactivity for propene polymerization is reported. The compounds 1-3 polymerize propene, albeit in a much lower activity than the reported [Ti(η5-C5Me5Me3]/B(C6F5)3 catalyst. Unlike the reported [Ti(η5-C5Me5Me3]/B(C6F5)3 catalyst, the quasi living polymerization was not observed. Instead, we observe rather unusual temperature effects when the trityl salt [Ph3C][B(C6F5)4] was used as activator. The activity increases with increasing temperature, whereas when B(C6F5)3 is used a decrease is observed The rather broad (>2) PDI indicates multisite catalysts, and 13C-NMR indicates predominantly atactic polypropene. The solid state structure of the hydrolysis product [{Ti(η5-C5H4(SiMe3)Cl2}O] (4) was determined.

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