Abstract
Doubly [SiMe2]-bridged group IV metallocenes, rac-(Me2Si)2{η5-C5H-3-(CHMe2)-5-Me}2MCl2 (M = Ti, Zr), have been synthesized, and a crystal structure of rac-(Me2Si)2{η5-C5H-3-(CHMe2)-5-Me}2TiCl2 has been determined by X-ray diffraction methods. Racemate−meso interchange occurs in benzene solution just above room temperature, affording an approximately 1:1 mixture of rac-(Me2Si)2{η5-C5H-3-(CHMe2)-5-Me}2TiCl2 and meso-(Me2Si)2{η5-C5H-3-(CHMe2)-5-Me}2TiCl2. Measurements of the kinetics of the approach to equilibrium reveal ΔH⧧ = 18(1) kcal·mol-1 and ΔS⧧ = −7(2) eu. The corresponding zirconium compound is configurationally stable.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have