Mixed noble metal-oxo clusters: platinum(IV)-gold(III) oxoanion [Pt IV 2 Au III 3 O 6 ((CH 3 ) 2 AsO 2 ) 6 ] .

The first discrete mixed platinum(IV)-gold(III) oxoanion [Pt IV 2 Au III 3 O 6 ((CH 3 ) 2 AsO 2 ) 6 ] - (1) was synthesized by reaction of H 2 Pt(OH) 6 with H[AuCl 4 ] in a simple one-pot procedure in aqueous solution at pH 7 and comprises two equivalent Pt IV O 6 (As(CH 3 ) 2 ) 3 units which are linked by three square-planar Au III O 4 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 ( 1 H, 13 C, 195 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.