Group 4 Metal and Lanthanide Complexes in the Oxidation State +3 with Tris(trimethylsilyl)silyl Ligands

A number of paramagnetic silylated d1 group 4 metallates were prepared by reaction of potassium tris­(trimethylsilyl)­silanide with group 4 metallates of the type K­[Cp2MCl2] (M = Ti, Zr, Hf). The outcomes of the reactions differ for all three metals. While for the hafnium case the expected complex [Cp2Hf­{Si­(SiMe3)3}2]− was obtained, the analogous titanium reaction led to a product with two Si­(H)­(SiMe3)2 ligands. The reaction with zirconium caused the formation of a dinuclear fulvalene bridged complex. The desired [Cp2Zr­{Si­(SiMe3)3}2]− could be obtained by reduction of Cp2Zr­{Si­(SiMe3)3}2 with potassium. In related reactions of potassium tris­(trimethylsilyl)­silanide with some lanthanidocenes Cp3Ln (Ln = Ce, Sm, Gd, Ho, Tm) complexes of the type [Cp3Ln Si­(SiMe3)3]− with either [18-crown-6·K]+ or the complex ion [18-crown-6·K·Cp·K·18-crown-6] as counterions were obtained. Due to d1 or fn electron configuration, unambiguous characterization of all obtained complexes could only be achieved by single crystal XRD diffraction analysis