Monomers, chains and layers of [Pt2(SO4)4] units in the crystal structures of the platinum(III) sulfates (NH 4)2[Pt2(SO4)4(H 2O)2], K4[Pt2(SO4) 5] and Cs[Pt2(SO4)3(HSO 4)]

Abstract

The reaction of Pt(NO3)2 with concentrated sulfuric acid in sealed glass ampoules at 400 °C causes reduction of the nitrate ion to NH4+ and leads to single crystals of (NH 4)2[Pt2(SO4)4(H 2O)2] [triclinic, P1, Z = 1, a = 749.96(9), b = 754.2(1), c = 765.4(1) pm, a = 102.15 (1)°, β = 110.23(1)°, γ = 100.87(1)°, Rall = 0.0677]. In the crystal structure, Pt 2 dumbbells are coordinated by four bidentate-bridging sulfate ions and two axial H2O molecules. The replacement of the axial H 2O molecules with SO42-, which can be observed in the crystal structure of K4[Pt2(SO4) 5] [triclinic, P̄, Z = 2, a = 975.6(1), b = 1331.8(1), c = 1491.0(1) pm, a = 101.156(8)°, β = 96.278(8)°, γ = 102.849(8)°, Rall = 0.0459], causes a connection of the dumbbells into chains of the composition ∞1[Pt2(SO 4)4/1-(SO4)2/2]4-. K 4[Pt2(SO4)5] has been obtained from the reaction of K2[PtCl4] and concentrated H 2SO4 at 400 °C in sealed glass tubes. The same reaction with Cs2[PtCl4] instead of K 2[PtCl4] leads to Cs[Pt2(SO4) 3(HSO4)] [monoclinic, P21/C, Z = 4, a = 1724.8(2), b = 881.28(9), c = 935.1(1) pm, β = 100.397(8)°, R all = 0.0458]. In the crystal structure, part of the bidentate-bridging sulfate ions of the [Pt2(SO4) 4] core act as monodentate ligands to further Pt2 dumbbells leading to anionic layers of the composition ∞ 2[Pt2(SO4)4/2(SO4) 2/1]2- and neutral units with the formula ∞2[Pt2(SO4)4/2(HSO 4)2/1]. The two types of layers are stacked alternatingly with the ten coordinate Cs+ ions. © Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005.