Mixed Noble Metal-oxo Clusters: Platinum(IV)-gold(III) Oxoanion [PtAuO((CH)AsO)]

The first discrete mixed platinum(IV)-gold(III) oxoanion [PtAuO((CH)AsO)] (1) was synthesized by reaction of HPt(OH) with H[AuCl] in a simple one-pot procedure in aqueous solution at pH 7 and comprises two equivalent PtO(As(CH)) units which are linked by three square-planar AuO units. Polyanion 1 could be isolated as a potassium or sodium salt in good yield, which were structurally characterized in the solid state by single-crystal XRD and TGA, and in solution by multinuclear (H, C, Pt) NMR, indicating that polyanion 1 is stable in solution, which was confirmed by ESI-MS studies. The sodium salt of 1 undergoes a clean single-crystal-to-single-crystal (SCSC) structural transformation upon rehydration and dehydration.