Efficient and selective alkene hydrosilation promoted by weak, double Si–H activation at an iron center

Abstract

Cationic iron complexes [Cp*(ⁱPr₂MeP)FeH₂SiHR]⁺, generated and characterized in solution, are very efficient catalysts for the hydrosilation of terminal alkenes and internal alkynes by primary silanes at low catalyst loading (0.1 mol%) and ambient temperature. These reactions yield only the corresponding secondary silane product, even with SiH₄ as the substrate. Mechanistic experiments and DFT calculations indicate that the high rate of hydrosilation is associated with an inherently low barrier for dissociative silane exchange (product release).