Concentration- and Solvation-Induced Reversible Structural Transformation and Assembly of Polynuclear Gold(I) Sulfido Complexes

A series of polynuclear gold(I) sulfido complexes of bis(diphenylphosphino)amine ligands has been synthesized and characterized. A rather small variation in the conformation of the bis(diphenylphosphino)amine ligands has led to distinct differences in the identity of the polynuclear gold(I) sulfido complexes formed. Unprecedented concentration-dependent and solvation-dependent reversible cluster-to-cluster transformation between a dodecanuclear gold(I) sulfido complex (L^Me-Au₁₂) and a hexanuclear gold(I) sulfido complex (L^Me-Au₆) has been observed. The transformation process has been monitored not only by ¹H and ³¹P{¹H} NMR spectroscopy but also by UV-vis absorption spectroscopy and high-resolution electrospray ionization mass spectrometry (HR-ESI-MS) in the solution state. This work has provided a simple approach to achieve structure modulation of gold(I) sulfido complexes and an understanding of supramolecular transformations via external stimuli.