Synthesis, structure and properties of the Cp2Zr{CH(SiMe3)2}+ cation
作者:Edward J. Stoebenau、Richard F. Jordan
DOI:10.1016/j.jorganchem.2006.08.033
日期:2006.11
The generation and properties of the Cp2ZrCH(SiMe3)(2)}(+) cation are described. An X-ray crystallographic analysis shows that the carborane salt [Cp2ZrCH(SiMe3)(2)}][HCB11Me5Br6] contains an agostic Zr-mu-Me-Si interaction in the solid state. Low temperature NMR spectra of the borate salt [Cp2ZrCH(SiMe3)(2)}][B(C6F5)(4)] show that this interaction is retained in solution. Variable temperature NMR spectra establish that the SiMe2(mu-Me) and unbound SiMe3 units of Cp2ZrCH(SiMe3)(2)}(+) exchange by a "pivot" process involving partial rotation around the Zr-CH(SiMe3)(2) bond, with a barrier of Delta G(double dagger) = 9.2(1) kcal/mol at -89 degrees C. Cp2ZrCH(SiMe3)(2)}(+) does not coordinate alkenes or alkynes. (c) 2006 Elsevier B.V. All rights reserved.