Gold(III) complexes with monodentate coordinated diazines: An evidence for strong electron-withdrawing effect of Au(III) ion

Abstract

Gold(III) complexes containing heterocyclic diazines as ligands, [AuCl3(az)], have been synthesized. Regardless of different stoichiometric ratio of the starting [AuCl4]− complex and diazine ligand, only gold(III) complexes with monodentatly coordinated diazines have been isolated and characterized by NMR and X-ray diffraction techniques. The [AuCl3(az)] complexes with stronger heteroaromatic bases, pyridazine and pyrimidine, form isostructural crystals in which the molecules are engaged in columnar Au⋯Cl interactions and π⋯π stacking within the columns, and utilize the uncoordinated nitrogen atom as an acceptor of C–H⋯N hydrogen bond. On the other hand, the [AuCl3(pz)] complex containing the weakest pyrazine base does not engage its uncoordinated nitrogen atom in intermolecular interactions.