Double salt crystal structure of nona­sodium dihydrogen nona­vanadoplatinate(IV) tri­hydrogen nona­vanadoplatinate(IV) tetra­contahydrate: stepwise-protonated nona­vanadoplatinate(IV)

摘要

Nonavanadoplatinate [Pt^IVV9O28]⁷⁻, which is the first heteropolyoxovanadate in the deca­vanadate framework, [V10O28]⁶⁻, has been investigated crystallographically. The title compound, Na9[H2Pt^IVV9O28][H3Pt^IVV9O28]·40H2O, was obtained by a hydro­thermal reaction at pH = 2. This compound contains two different protonated heteropolyoxovanadates, [H2Pt^IVV9O28]⁵⁻ [polyanion (A)] and [H3Pt^IVV₉O₂₈]⁷⁻ [polyanion (B)]. The locations of the H atoms on the protonated O atoms were observed in difference Fourier maps and confirmed by the inter­polyanion hydrogen bonds, bond-length elongation and bond-valence-sum (VBS) analysis. The two (Pt and V)-bound μ₂-O atoms are protonated in both polyanions. The position of the third protonated O atom in polyanion (B) is an inter­esting feature of the structure, being located on one (V₂)-bound μ₂-O atom. The discrete heteropolyanions form a dimer, {H₅[PtV₉O₂₈]₂}⁹⁻, through five inter­polyanion hydrogen bonds. Additional O—H⋯O hydrogen bonds and interactions between Na⁺ cations and water molecules as well as terminal O atoms of one of the polyanions consolidate the crystal packing.