Silylmethyl and related complexes. Part I. Kinetically stable alkyls of titanium(IV), zirconium(IV), and hafnium(IV)
Complexes of the type Cp2M(CH2M′Me3)2(Cp =π-C5H5; M = Ti, Zr, or Hf; M′= Si or Ge) have been prepared from Me3M′CH2Li, or less satisfactorily from the Grignard reagent, and Cp2MCl2 in ether. Cp2Zr(Cl)CH2SiMe3 was prepared via Me3SiCH2MgCl in ether–methylene chloride. Isoleptic complexes (RnMe3 –nSiCH2)4M (M = Ti, Zr, or Hf; n= 0–2; R = Ph or PhCH2) have been prepared by the reaction of MCl4 with Me3SiCH2Li in ether or hexane, RnMe3 –nSiCH2MgCl in ether, or (RnMe3 –nSiCH2)2Mg in hexane. The complexes are thermally more stable than their methyl analogues; oxidative stabilities of the isoleptic compounds correlate with the degree of steric shielding at the metal centre. Spectroscopic data are provided, and the reactions of the isoleptic compounds with water, iodine, and acetylacetone are described.
- This article is part of the themed collection: A collection of papers in memory of Professor Michael Lappert