Chelate complexes of gold(III)

New gold(III) complexes involving substituted picolinic acids acting as bidentate ligands have been characterised: AuCl₂(LL), and Au(LL)₂]⁺ (H-LL=hydroxy- or carboxy-substituted picolinic acid). The latter readily undergo deprotonation of the substituent on one ligand, to yield novel uncharged complexes which appear to be polymeric via hydrogen bonds between protonated and depronated substituents. A completely depronated anionic complex has also been obtained. The characterisation of these materials was considerably aided by¹⁹⁷Au Mussbauer spectroscopy.