Palladium(IV) in an Oxoanionic Environment: The XeF2 Assisted Synthesis of [Pd(S2O7)3]2−

For the first time tetravalent palladium is detected, coordinated exclusively by simple oxoanions. Stabilization was achieved by formation of the [Pd(S₂O₇)₃]^2? complex in which three chelating disulfate groups surround the metal atom. The salt K₂[Pd(S₂O₇)₃] could only be obtained if the reaction of K₂[PdCl₆] and neat SO₃ was performed in the presence of XeF₂.     

Reactions with Oleum under Harsh Conditions: Characterization of the Unique [M(S2O7)3]2− Ions (M=Si,Ge, Sn) in A2[M(S2O7)3] (A=NH4, Ag)

The reactions of group 14 tetrachlorides MCl₄ (M=Si, Ge, Sn) with oleum (65 % SO₃) at elevated temperatures lead to the unique complex ions [M(S₂O₇)₃]^2?, which show the central M atoms in coordination with three chelating S₂O₇^2? groups. The mean distances M? O within the anions increase from 175.6(2)–177.5(2) pm (M=Si) to 186.4(4)–187.7(4) pm (M=Ge) to 201.9(2)–203.5(2) pm (M=Sn). These distances are reproduced well by DFT calculations. The same calculations show an increasing positive charge for the central M atom in the row Si, Ge, Sn, which can be interpreted as the decreasing covalency of the M? O bonds. For the silicon compound (NH₄)₂[Si(S₂O₇)₃], ²⁹Si solid‐state NMR measurements have been performed, with the results showing a signal at ?215.5 ppm for (NH₄)₂[Si(S₂O₇)₃], which is in very good agreement with theoretical estimations. In addition, the vibrational modes within the [MO₆] skeleton have been monitored by Raman spectroscopy for selected examples, and are well reproduced by theory. The charge balance for the [M(S₂O₇)₃]^2? ions is achieved by monovalent A⁺ counter ions (A=NH₄, Ag), which are implemented in the syntheses in the form of their sulfates. The sizes of the A⁺ ions, that is, their coordination requirements, cause the crystallographic differences in the crystal structures, although the complex [M(S₂O₇)₃]^2? ions remain essentially unaffected with the different A⁺ ions. Furthermore, the nature of the A⁺ ions influences the thermal behavior of the compounds, which has been monitored for selected examples by thermogravimetric differential thermal analysis (DTA/TG) and XRD measurements.     

Crystal structure refinement for trans-[Pd(NO3)2(H2O)2]

Single crystals of trans-[Pd(NO₃)₂(H₂O)₂] were obtained, and the crystal structure of this complex, previously obtained for polycrystals, was refined. Crystal data (BRUKER X8APEX diffractometer): a = 4.9973(7) Å, b = 10.5982(14) Å, c = 11.7008(17) Å, V = 619.70(15) ų, space group Pbca, Z = 4, d _calc = 2.856 g/cm³. The structure is composed of neutral complexes with a trans configuration. The square plane environment of the Pd atom is formed by four oxygen atoms (Pd-O(NO₃) 1.999(5) Å, Pd-O(H₂O) 2.030(5) Å) and completed to a distorted bipyramid by two intramolecular contacts (Pd…O(NO₃) 2.926 Å). The shortest hydrogen bonds are O…H 2.72 Å.     

Towards Polysulfuric Acids: The Hydrogentrisulfate Anion [HS3O10]− in A[HS3O10] (A=Na,K, Rb)

The reaction of Na₂SO₄ and K₂SO₄ with fuming sulfuric acid (65 % SO₃) yielded colorless extremely sensitive crystals of Na[HS₃O₁₀] (monoclinic; P2₁/n (No. 14); Z=4; a=707.36(2), b=1378.56(4), c=848.10(3) pm; β=94.817(1)°; V=824.09(4) ? 10⁶ pm³) and K[HS₃O₁₀] (orthorhombic; Pccn (No. 56); Z=4; a=1057.16(3), b=807.81(2), c=897.57(2) pm; V=766.51(3) ? 10⁶ pm³). The analogous rubidium compound Rb[HS₃O₁₀] (orthorhombic; Pnma (No. 62); Z=4; a=891.43(3), b=1095.34(4), c=839.37(3) pm; V=819.58(5) ? 10⁶ pm³) originates from the reaction of Rb₂CO₃ and SO₃. All of the different structures contain the hitherto unknown anion [HS₃O₁₀]^? and are stamped by strong hydrogen bonds linking the anions either to dimers or chains. Theoretical investigations by DFT methods give further insight in the structural characteristics of [HS₃O₁₀]^?. The preparation of the [HS₃O₁₀]^? anion can be seen as an important milestone on our way to the still elusive polysulfuric acids.     

Ferromagnetic Ordering in the Layer‐Structured Pd(HS2O7)2

The reaction of (NO₂)(CF₃SO₃) and elemental palladium in oleum (65 % SO₃) leads to violet single crystals of Pd(HS₂O₇)₂ (monoclinic, P2₁/c, Z=2, a=927.80(9), b=682.58(7), c=920.84(9) pm, β=117.756(2)°, wR₂=0.0439). In the crystal structure, the Pd²⁺ ions show an uncommon octahedral coordination of six oxygen atoms belonging to six HS₂O₇^? ions. The linkage of [PdO₆] octahedra and the hydrogendisulfate anions leads to a layer structure, and the layers are held together by hydrogen bonds. The unusual coordination of the Pd²⁺ ions results in an electronic d⁸ high‐spin configuration, which leads to the paramagnetic behavior of the compound. Moreover, at low temperature, a ferromagnetic ordering was observed with a Curie temperature of 8 K.     

A Highly Triflated Rare‐Earth Ion in [Eu(O3SCF3)8]5−

The reaction of Eu₂O₃ with fuming nitric acid, trifluormethanesulfonic acid, and its anhydride in torch‐sealed glass ampoules at 120 °C gave the europium compound (NO)₅[Eu(O₃SCF₃)₈] (orthorhombic, Fddd, Z=16, a=1932.69(4), b=2878.44(7), c=2955.12(7) pm, V=16439.7(7) ų). The compound exhibits the [Eu(O₃SCF₃)₈]^5? anion showing for the first time a lanthanide ion that is exclusively coordinated by eight triflate anions. The anion has been further investigated by DFT calculations, which also allowed clear assignment of the vibrational spectra. Moreover, magnetochemical and luminescence measurements gave additional insight into the properties of this complex. The luminescence spectra revealed that the Eu³⁺ ions are in a pseudo D_4d symmetric environment.     

The electronic structure of the tris(ethylene) complexes [M(C2H4)3] (M=Ni, Pd, and Pt): a combined experimental and theoretical study

In this article we analyze in detail the electronic properties of the D(3h)-symmetric tris(ethylene) complexes of nickel, palladium, and platinum ([M(C(2)H(4))(3)] M=Ni, Pd, Pt). In the case of [Pd(C(2)H(4))(3)] the analysis is based on new experimental IR and Raman spectra for the matrix-isolated molecules and in all cases on the results of quantum-chemical (DFT) calculations. The experimental spectra collected for [Pd(C(2)H(4))(3)] provide evidence for several previously unobserved vibrational modes, including the in-phase and out-of-phase nu(C-C) and delta(CH(2)) modes, and the in-phase nu(M-C) mode. Special consideration is given to possible inter-ligand interactions. The interaction force constant f(CC,CC) between two C(2)H(4) ligands can be directly estimated from the spectra, and its very small value (0.002 N m(-1)) indicates the absence of any significant inter-ligand interaction. An analysis of the topology of the theoretical electron density distribution, rho(r), and the corresponding Laplacian, nabla(2)rho(r), for [Pd(C(2)H(4))(3)] and its lighter and heavier homologues [Ni(C(2)H(4))(3)] and [Pt(C(2)H(4))(3)], respectively, is in full agreement with the conclusions drawn from the experimental results. The combined experimental and quantum-chemical results provide detailed insights in the electronic properties of these prototypical ethylene complexes.     

Synthesis,Crystal Structure,Vibrational Spectroscopy,and Thermal Behavior of Y[B_2O_3（OH）]_3

The hydroxy yttrium hexaborate,Y[B2O3(OH)]3,has been synthesized under mild hydrothermal conditions at 458 K.The crystal structure was solved and refined from single-crystal X-ray diffraction.It adopts a trigonal space group R3c(No.161) with a = 8.3942(4),c = 20.6484(12) ,V = 1260.03(12) 3,YB6H3O12,Mr = 348.79,Z = 6,Dc = 2.758 g/cm3,F(000) = 1008,μ = 7.015 mm-1,R = 0.0321 and wR = 0.0772.Its crystal structure is made up of six-membered rings,alternating three-connected [BO3(OH)] tetrahedra and planar [BO3] trigonal groups,which are interconnected with each other by sharing their common oxygen corners to form a three-dimensional framework structure with six-membered ring channels that are occupied by the yttrium atoms and run along the c axis.FT-IR,Raman,and TG-DTA results are also presented.     

The Protonation of HSO3F: Preparation and Characterization of Fluorodihydroxyoxosulfonium Hexafluoroantimonate [H2SO3F]+[SbF6]−

Sulfurtrioxide reacts with the superacidic solutions XF/SbF₅ (X=H, D) to form the corresponding salts [X₂SO₃F]⁺[SbF₆]^?, which are the protonated forms of fluorosulfuric acid. The salts have been characterized by vibrational spectroscopy and a single‐crystal structure analysis. [H₂SO₃F]⁺[SbF₆]^? crystallizes in the monoclinic space group P2₁/n (no. 14) with four formula units in the unit cell. The crystal structure possesses a distorted tetrahedral O₃SF skeleton of the cations, which are linked with two strong hydrogen bridges to [SbF₆]^? anions and forms a one‐dimensional chain. The crystal structure and the vibrational spectra are compared to the quantum‐chemical‐calculated free [H₂SO₃F]⁺ cation. Additionally, an [H₂SO₃F(HF)₂]⁺ unit was calculated at the RHF/6‐311⁺⁺G(d,p) level to simulate H???F hydrogen bridges found in the solid state.     

Synthesen und Schwingungsspektren der homoleptischen Acetonitrilkomplex-Kationen [Au(NCCH3)2]+, [Pd(NCCH3)4]2+, [Pt(NCCH3)4]2+ und des Adduktes CH3CN · SbF5. Kristallstrukturen der Salze [M(NCCH3)4][SbF6]2 · CH3CN,M = Pd,Pt

The Syntheses and Vibrational Spectra of the Homoleptic Metal Acetonitrile Cations [Au(NCCH₃)₂]⁺, [Pd(NCCH₃)₄]²⁺, [Pt(NCCH₃)₄]²⁺, and the Adduct CH₃CN · SbF₅. The Crystal and Molecular Structures of [M(NCCH₃)₄][SbF₆]₂ · CH₃CN, M = Pd or Pt Solvolyses of the homoleptic metal carbonyl salts [M(CO)₄][Sb₂F₁₁]₂, M = Pd or Pt, in acetonitrile leads at 50 °C both to complete ligand exchange for the cations as well as to a conversion of the di-octahedral anion [Sb₂F₁₁]^– into [SbF₆]^– and the molecular adduct CH₃CN · SbF₅ according to: [M(CO)₄][Sb₂F₁₁]₂ + 7 CH₃CN → [M(NCCH₃)₄][SbF₆]₂ · CH₃CN + 2 CH₃CN · SbF₅ + 4 CO M = Pd, Pt The monosolvated [M(NCCH₃)₄][SbF₆]₂ · CH₃CN are obtained as single crystals from solution and are structurally characterized by single crystal x-ray diffraction. Both salts are isostructural. The cations are square planar but the N–C–C-sceletial groups of the ligands depart slightly from linearity. The new acetonitrile complexes as well as [Au(NCCH₃)₂][SbF₆] and the adduct CH₃CN · SbF₅ are completely characterized by vibrational spectroscopy.     

The effect of coordinated water on the connectivity of uranium(IV) sulfate x‐hydrate: [U(SO4)2(H2O)5]·H2O and [U(SO4)2(H2O)6]·2H2O,and a comparison with other known structures

Two new solid‐state uranium(IV) sulfate x‐hydrate complexes (where x is the total number of coordinated plus solvent waters), namely catena‐poly[[pentaaquauranium(IV)]‐di‐μ‐sulfato‐κ⁴O:O′] monohydrate], {[U(SO₄)₂(H₂O)₅]·H₂O}_n, and hexaaquabis(sulfato‐κ²O,O′)uranium(IV) dihydrate, [U(SO₄)₂(H₂O)₆]·2H₂O, have been synthesized, structurally characterized by single‐crystal X‐ray diffraction and analyzed by vibrational (IR and Raman) spectroscopy. By comparing these structures with those of four other known uranium(IV) sulfate x‐hydrates, the effect of additional coordinated water molecules on their structures has been elucidated. As the number of coordinated water molecules increases, the sulfate bonds are displaced, thus changing the binding mode of the sulfate ligands to the uranium centre. As a result, uranium(IV) sulfate x‐hydrate changes from being fully crosslinked in three dimensions in the anhydrous compound, through sheet and chain linking in the tetra‐ and hexahydrates, to fully unlinked molecules in the octa‐ and nonahydrates. It can be concluded that coordinated waters play an important role in determining the structure and connectivity of U^IV sulfate complexes.     

Darstellung und Kristallstrukturen der ersten Alkalimetall‐hexacarbonatooxotetraberyllate: K6[Be4O(CO3)6] · 7 H2O und K6[Be4O(CO3)6]

Preparation and Crystal Structures of the first Alkalimetall‐hexacarbonato‐oxotetraberyllates: K₆[Be₄O(CO₃)₆] · 7 H₂O and K₆[Be₄O(CO₃)₆] K₆[Be₄O(CO₃)₆] · 7 H₂O has been prepared by dissolving freshly precipitated Be(OH)₂ in an aqueous KHCO₃ solution. After enriching the title compound by extraction with ethanol the heptahydrate crystallizes from the organic phase (triklin, P1¯ (No. 2) with a = 951, 01(11), b = 958, 45(12), c = 1601, 7(2) pm, α = 79, 253(13)°, β = 78, 943(12)°, γ = 65, 119(12)°, V_EZ = 1290, 6(3)·10⁶ pm³, Z = 2). Thermal decomposition forms rhombohedral crystals of the anhydrous compound (trigonal‐rhombohedric, R3¯ (No. 148) with a = 1416, 42(6), c = 1704, 5(1) pm, V_EZ = 2961, 4(3)·10⁶ pm³, Z = 6).     

Alkalimolybdotellurate: Darstellung und Kristallstruktur von Rb6[TeMo6O24] · 10H2O und Rb6[TeMo6O24] · Te(OH)6 · 6H2O

Alkaline Molybdotellurates: Preparation and Crystal Structures of Rb₆[TeMo₆O₂₄] · 10H₂O and Rb₆[TeMo₆O₂₄] · Te(OH)₆ · 6H₂O Single crystals of Rb₆[TeMo₆O₂₄] · 10 H₂O and Rb₆[TeMo₆O₂₄] · Te(OH)₆ · 6 H₂O, respectively, were grown from aqueous solution. Rb₆[TeMo₆O₂₄] · 10 H₂O possesses the space group P1 . The lattice dimensions are a = 963.40(13), b = 972.56(12), c = 1 056.18(13) pm, α = 97.556(10), β = 113.445(9), γ = 102.075(10)°; Z = 1, 2 860 reflections, 215 parameters refined, R_g = 0.0257. The centrosymmetrical [TeMo₆O₂₄]^6? anions are stacked parallel to [010]. Rb(2) is coordinated with one exception by water molecules only. Folded chains consisting of [TeMo₆O₂₄]^6? anions and Rb(2) coordination polyhedra which are linked to pairs represent the prominent structural feature. Rb₆[TeMo₆O₂₄] · Te(OH)₆ · 6 H₂O crystallizes monoclinically in the space group C2/c with a = 1 886.4(3), b = 1 000.9(1), c = 2 126.5(3) pm, and β = 115.90(1)°; Z = 4, 3 206 reflections, 240 parameters refined, R_g = 0.0333. It is isostructural in high extent with (NH₄)₆[TeMo₆O₂₄] · Te(OH)₆ · 7 H₂O. Hydrogen bonds between Te(OH)₆ molecules and [TeMo₆O₂₄]^6? anions establish infinite strands. The [TeMo₆O₂₄]^6? anions gather around Te(OH)₆ providing channel-like voids extending parallel to [001].     

Dynamic disorder in ammonium oxofluorotungstates (NH4)2WO2F4 and (NH4)3WO3F3

Ammonium oxofluorotungstates, (NH₄)₂WO₂F₄ and (NH₄)₃WO₃F₃, are characterized by vibration spectroscopy and quantum chemistry methods with the use of NMR ¹⁹F and ¹H data. It is shown in the approximation of the density-functional theory that in isolated octahedrons [WO₂F₄]^2? and [WO₃F₃]^3? the mutual arrangement of oxygen atoms in cis-position corresponds to the energy minimum. The presence of intraspheric disorder in [WO₃F₃]^3? (unlike [WO₂F₄]^2?) explains the complex character of vibrational spectra of this anion and eliminates existent in the literature differences in their interpretation (between C _2v and C _3v structure variants). Models of intraspheric dynamics of [WO₃F₃]^3? are discussed.