E–H (E = B, Si, Ge) bond activation of pinacolborane, silanes, and germanes by nucleophilic palladium carbene complexes

Abstract

The reactivity of two nucleophilic palladium carbenes, [PC(sp²)P]Pd(PMe₃) and [PC(sp²)P]Pd(PPh₃), where [PC(sp²)P] = bis[2-(di-iso-propylphosphino)phenyl]methylene, toward the E–H bond activation of Ph_4−nEH_n (E = Si, Ge; n = 1–3) and pinacolborane (HBpin) is discussed. Unlike previous reports, both types of isomer species, hydride [PC(EH_n−1Ph_4−n)P]PdH or [PC(Bpin)P]PdH and silyl/germyl [PC(H)P]Pd(EH_n−1Ph_4−n), were observed depending on the substrate and the phosphine ligand, showing that the polarity of the Pd–C bond can be tuned by the phosphine substituents.