A new synthetic access to the Lewis acid [Au(OTeF5)3] and the preparation of the related, unprecedented anion [Au(OTeF5)4]− with inorganic or organic cations starting from commercially available and easy-to-handle gold chlorides are presented. In this first extensive study of the Lewis acidity of a transition metal teflate complex using different experimental and quantum chemical methods, [Au(OTeF5)3] was classified as a Lewis superacid. The solid state structure of the triphenylphosphane adduct [Au(OPPh3)(OTeF5)3] was determined, representing the first structural characterization of an adduct of this highly reactive [Au(OTeF5)3]. Therein, the coordination environment around the gold center slightly deviates from the typical square planar geometry. The related, unprecedented anion [Au(OTeF5)4]− shows a similar coordination motif.
