Discrete Platinum(II/IV)-Arsenito Clusters with Pt-As and Pt-O Bonding: [PtIV(As3O6)2]2-, [Pt4 II(H2AsO3)6(HAsO3)2]2-, and [Pt2 IIAs6W4O28]10-

The first two discrete, fully inorganic platinum(II/IV)-arsenito clusters, [fac-Pt-IV(As3O6)(2)](2-) (PtAs6) and [Pt-4(II)(H2AsO3)(6)(HAsO3)(2)](2-) (Pt4As8), as well as the platinum(II)-arsenito heteropolytungstate [(Pt2As6W4O28)-As-II](10-) (Pt2As6W4), have been synthesized in aqueous media using simple one-pot reaction conditions. In PtAs6, a Pt-IV ion is coordinated to two cyclic, tridentate As3O6 units via oxo-donation (Pt-IV-O similar to 2.02 & Aring;). In Pt4As8, each Pt-II ion is coordinated to four AsO3 ligands via two oxygens and two As-III atoms in a square-planar fashion (Pt-II-As-III 2.31 & Aring;, Pt-II-O 2.07 & Aring;), resulting in an open cage-like structure, which forms a strong tetrameric assembly in the solid state mediated by two K+ counterions. In Pt2As6W4, each Pt-II ion is coordinated by the As atoms of three AsO3 ligands (Pt-II-As-III 2.38 & Aring;) and an oxo group (Pt-II-O 2.07 & Aring;) in addition to bridging two tungsten ions, and this polyanion was characterized in solution by Pt-195 NMR.