111287-33-3Relevant articles and documents
Dimesitylsilyl derivatives of zirconium
Roddick, Dean M.,Heyn, Richard H.,Tilley, T. Don
, p. 324 - 330 (2008/10/08)
The preparation and characterization of (THF)2LiSiHMes2 (1, Mes = mesitvl) are reported. Compound 1 reacts with Cp2Zr(Me)Cl (Cp = η5-C5H5) to afford thermally unstable Cp2Zr(SiHMes2)Me (2), characterized by NMR spectroscopy. Similarly, the reaction of 1 with Cp*2Zr(Me)Br (Cp* = η5-C5Me5) provides the mixed alkyl silyl Cp*2Zr(SiHMes2)Me (3), which is stable for prolonged periods at room temperature. Compound 3 reacts cleanly with 1 equiv of HCl to give the chloro derivative Cp*2Zr(SiHMes2)Cl (4) and methane. Whereas carbon monoxide inserts cleanly into the Zr-C bond of 2, preferential CO insertion into the Zr-Si bond of 3 is observed. These reactions give Cp2Zr(η2-COMe)SiHMes2 (5) and Cp*2Zr-(η2-COSiHMes2)Me (6), respectively. Compound 6 is not stable in solution and slowly isomerizes to the enolate hydride Cp*2Zr[OC(=CH2)SiHMes2]H (7). The mechanism of the latter conversion is discussed. Hydrogen is shown to cleave the Zr-Si bond of 3 faster than the Zr-C bond. Reaction of 3 with AgOSO2CF3 results in oxidative cleavage of the Zr-Si bond giving MeS2HSiSiHMes2, Mes2SiH(OSO2CF3), MeS2SiH(Me), and Cp*2Zr(Me)OSO2CF3 (9), which was independently prepared from Cp*2ZrMe2 and AgOSO2CF3. Reaction of Cp*2ZrCl2 with 2 equiv of 1 does not give a bis(silyl) complex but instead results in dehydrohalogenation to MeS2SiH2 and the metallacycle Cp*2ZrCH2CCHCMeCHCMeCSiHMes (10).
