Gold(I) complexes of unidentate and bidentate phosphorus-, arsenic-, antimony-, and sulphur-donor ligands

Complexes of gold(I) with a variety of unidentate and potentially chelating P-, As-, Sb-, and S-donor ligands have been characterised by analysis, 1H n.m.r., i.r., and u.v.–visible spectroscopy, and electrical conductivity. In the majority of cases, the gold atom is two co-ordinate, [AuX(L)] or [XAu(L′–L′)AuX](L = unidentate ligand, L′–L′= bidentate ligand, X = Cl, Br, or SCN), but a few examples of probable three-co-ordination have been found, [AuXL2] or [AuX(L′–L′)]. With bidentate ligands, inflexibility of the backbone seems to be the key factor in promoting chelation. The ease of formation of cationic complexes [AuL2]+ is shown to depend on the polarity of the solvent.