Synthesis and structures of diphosphinoamide complexes of nickel, palladium and platinum

Lithium bis(diphenylphosphino)amide, (THF)3LiN(PPh2)2 reacts with Ni(COD)2 or PtMe2(COD) to give the corresponding bimetallic complexes (THF)3LiN(PPh2)2Ni(COD) and (THF)3LiN(PPh2)2PtMe2. Reaction of (THF)3LiN(PPh2)2Ni(COD) with Me3SnCl gave the Ni–Sn derivative, also accessible from Me3SnN(PPh2)2. The silyl derivatives Me3SiN(PPh2)2M [M = Ni(COD), PtMe2] were obtained similarly as red and colourless crystals, respectively. By contrast, the reaction with PdCl2(COD) afforded an insoluble yellow adduct which, on attempted recrystallisation afforded a small amount of a Pd(I) product, [PdCl{HN(PPh2)2}]2. The crystal structures of the Ni and Pt complexes are based on MP2N four-membered rings. The geometric parameters proved rather insensitive to changes in the N-main group element bond. In all cases the amido-nitrogen atom deviated slightly from trigonal-planar geometry, most probably as the consequence of packing forces.

Graphical abstractThe syntheses and single-crystal X-ray structures of bimetallic Ni–Li, Ni–Sn, Ni–Si, Pt–Li and Pt–Si complexes are described, based on the [amidobis(phosphine)]− anion as bridging ligand. The structures are based on MP2N four-membered rings, the geometric parameters of which proved rather insensitive to changes in the N-main group element bond.Figure optionsDownload full-size imageDownload as PowerPoint slide