LAUSR

Abstract The synthesis of four new bis(phosphine-amide) ligands E{NHC( O)-4-C6H4PPh2}2, E = 1,4-C6H4, 1,3-C6H4, 1,4-C6H4(CH2)2 or 1,4-C6H10, is reported along with a preliminary study of their properties. The ligands are slowly oxidized in solution to give the corresponding phosphine oxides, and they form complexes with gold(I) with bridged structures [Au2Cl2{μ-E(NHC( O)-4-C6H4PPh2)2}] or large macrocyclic structures [Au2{μ-E(NHC( O)-4-C6H4PPh2)2}2]X2, with X− = triflate or nitrate. A macrocyclic platinum(II) complex cis,cis-[Pt2Cl4{μ-1,4-C6H4 (NHC( O)-4-C6H4PPh2)2}2], was prepared but an attempt to isolate a related cationic complex [Pt2(dppp)2{μ-E(NHC( O)-4-C6H4PPh2)2}](OTf)4 led to ligand hydrolysis, with formation of the unusual phosphine-carboxylate bridged complex [Pt2(dppp)2{μ-O2C-4-C6H4PPh2)2}](OTf)2, dppp = Ph2P(CH2)3PPh2. The amide groups of the bis(phosphine-amide) ligands take part in hydrogen bonding, which may lead to self-assembly of more complex structures.