Unusual “Cation-like” Zirconocene Hydrosilyl Complex. Silylium Ligand or a Nonclassically Bonded Si−H?1

The novel zirconocene complexes [Cp‘ 2 Zr(μ-H)(SiHR)] 2 2+ [BR‘ n (C 6 F 5 ) 4 - n ] 2 2 - (Cp‘ = Cp, MeCp, Me 5 Cp; R = Ph or PhCH 2; R‘ = Bu or H) were isolated from silane dehydropolymerization reaction mixtures catalyzed by Cp‘ 2 ZrCl 2 /2BuLi/B(C 6 F 5 ) 3 or by [Cp‘ 2 Zr(μ-H)H] 2 /2B(C 6 F 5 ) 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.