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

Abstract

Lithium bis(diphenylphosphino)amide, (THF) 3LiN(PPh 2) 2 reacts with Ni(COD) 2 or PtMe 2(COD) to give the corresponding bimetallic complexes (THF) 3LiN(PPh 2) 2Ni(COD) and (THF) 3LiN(PPh 2) 2PtMe 2. Reaction of (THF) 3LiN(PPh 2) 2Ni(COD) with Me 3SnCl gave the Ni–Sn derivative, also accessible from Me 3SnN(PPh 2) 2. The silyl derivatives Me 3SiN(PPh 2) 2M [M = Ni(COD), PtMe 2] were obtained similarly as red and colourless crystals, respectively. By contrast, the reaction with PdCl 2(COD) afforded an insoluble yellow adduct which, on attempted recrystallisation afforded a small amount of a Pd(I) product, [PdCl{HN(PPh 2) 2}] 2. The crystal structures of the Ni and Pt complexes are based on MP 2N 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.