Synthesis and structural characterization of an unusual silylzirconium hydride complex

Dimethylzirconocene and dihydridozirconocene both catalyze the dehydrogenative coupling of primary and secondary organosilanes. Primary silanes give linear polysilanes and secondary silanes give tetraorganodisilanes. The reaction of dimethylzirconocene with a small excess of phenylsilane gives the unusual unsymmetrically substituted zirconocenesilylhydride dimer: Cp2Zr(SiMePhH)(μ-H)2(PhH2Si)ZrCp2. The structure of this product is deduced from a combination of nmr and crystallographic results. Although the nmr data suggest that dihydridozirconocene reacts with phenylsilane to give the corresponding symmetrical dimer (Me replaced by H) in solution, attempts to isolate this compound have not been successful.