Synthesis and Properties of the First [Au(dien)(N-heterocycle)]³⁺ Compounds

Novel Au^III(dien)­(N-heterocycle) compounds, including the first Au^IIIN₃(N-purine) examples, are reported. The acidity of the dien ligand is affected by the nature of the fourth ligand as a leaving group. The metal center of [Au­(dien)­(N-heterocycle)]³⁺ compounds was shown to be more stable to reduction than when Cl^– is present, with consequences for reactivity with biomolecules: specifically, significant enhancement of π–π-stacking interactions with tryptophan relative to isostructural and isoelectronic platinum­(II) and palladium­(II) compounds.