Unusual “Cation-like” Zirconocene Hydrosilyl Complex. Silylium Ligand or a Nonclassically Bonded Si−H?

The novel zirconocene complexes [Cp‘2Zr(μ-H)(SiHR)]2 2+[BR‘ n (C6F5)4 - n ]2 2- (Cp‘ = Cp, MeCp, Me5Cp; R = Ph or PhCH2; R‘ = Bu or H) were isolated from silane dehydropolymerization reaction mixtures catalyzed by Cp‘2ZrCl2/2BuLi/B(C6F5)3 or by [Cp‘2Zr(μ-H)H]2/2B(C6F5)3 combination catalysts. A total structure analysis of these compounds, performed by multinuclear, multidimensional NMR spectroscopy, shows that each zirconocene fragment bears a positive charge, which is delocalized between the metal center and hydrosilane ligand.