Synthesis of Ni(II) Complexes Supported by Tetradentate Mixed-Donor Bis(amido)/Phosphine/Phosphido Ligands by Phosphine Substituent Elimination

摘要

A convenient nickel-templated phenyl elimination route is described for the synthesis of phosphide-containing multidentate ligands from triarylphosphine precursors. Treating Ni(COD)(2) with the neutral bis(amine)/bis(phosphine) ligand precursor H-2(4Ph)[PNNP] affords bis(amido)/bis(phosphine) complex 1. Treatment of 1 with 1 equiv of KH leads to elimination of a phenyl group from one of the phosphine fi-aTnents, generating bis(amido)/phosphine/phosphido complex (3Ph)[PNNP]Ni- (2). Alternatively, excess KH or "BuLi affords the bis(amido)/bis(phosphide) complex (2Ph)[PNNP]Ni2- (3 or 4, respectively) by elimination of two phenyl substituents. These reactions are high-yielding and provide a unique and straightforward route to chelating phosphido ligands that would otherwise be challenging to synthesize.