Study of the state of uranogermanates MII(HGeUO6)2·6H2O in Aqueous Solutions (MII = Mn, Co, Ni, Cu, Zn)

The state of d-elements uranogermanates M^II(HGeUO₆)₂·6H₂O in aqueous salt solutions in a wide range of ionic strength, ionic composition, and acidity has been investigated. The pH ranges of the uranogermanates stability have been determined, and products of their transformation have been identified. Solubility, solubility equilibrium constant, and Gibbs energy of formation have been determined for the studied uranogermanates. Diagrams of uranium(VI), germanium(IV), and M(II) state in aqueous solutions and in equilibrium solid phases have been plotted.     

Low frequency vibrational spectra of crystalline and glassy metaborates Ba2MII(B3O6)2 (MII  Mg,Ca, Ni,Co, Cd)

The low frequency vibrational spectra (Raman and IR) of crystalline metaborates Ba₂M^II(B₃O₆)₂ (M^II  Mg, Ca, Ni, Co, Cd) are interpreted on the basis of a factor group analysis and with the help of ²⁴Mg²⁶Mg and ⁴⁰Ca⁴⁴Ca isotopic shifts. The far-IR spectra of the glasses appear as the envelope of the spectra of the corresponding crystalline compounds for M^II  Mg, Ca and Cd, but they exhibit an additional broad absorption centred near 400 cm⁻¹ for M^II  Co, Ni and Zn. This absorption is assigned to a fourfold coordination of part of the M^II cations, the remaining being in sixfold coordination (as in the crystal) and responsible for a broad absorption in the 300-200 cm⁻¹ region. The possible existence of correlations between coordination and vibrational frequencies is discussed for either alkali and alkaline-earth cations, or transition elements.     

New transition metal sulfates templated by 1,4-butanediamine, (C4H14N2)[MII(H2O)6](SO4)2·4H2O (MII: Co,Ni): Structure,reactivity and thermal decomposition

Two new hybrid materials, (C₄H₁₄N₂)[M^II(H₂O)₆](SO₄)₂·4H₂O (M^II: Co (I), Ni (II)), have been synthesised by slow evaporation method at room temperature and crystallographically characterized. They crystallise isotypically in the monoclinic system, space group P2₁/n, with the following unit-cell parameters a = 9.2285(3), b = 11.3333(4), c = 10.6693(4) Å, β = 109.004(2)°, Z = 2 and V = 1055.07(6) Å³ for I and a = 9.2127(2), b = 11.3182(2), c = 10.6434(2) Å, β = 109.094(1)°, Z = 2 and V = 1048.74(4) Å³ for II. The structure of the two supramolecular compounds consists of metallic cation octahedrally coordinated to six water molecules, sulfate anions, 1,4-butanediammonium cation and water molecules linked together via two types of hydrogen bonds, O–H?O and N–H?O. The two compounds are not stable at room temperature and their partial dehydration depends on the humidity of the environment. The thermal decomposition of precursors, studied by thermogravimetric analysis (TG) and temperature-dependent X-ray diffraction (TDXD), shows successive intermediate hydrates and crystalline anhydrous compounds upon dehydration.     

Coordination polymers of VIV—MII (MII = Mn,Co, Ni,Cd) with ethylmalonate anions

Russian Chemical Bulletin - A series of heterometallic 1D coordination polymers {[MII(VIVO)(Etmal)2(H2O)5] ? 2 H2O}n (MII = Mn (1), Co (2), Ni (3), Cd (4)) were synthesized. These compounds...     

2D coordination polymers of AgI—MII (MII = Ni,Cu) with anions of substituted malonic acids

Russian Chemical Bulletin - Heterometallic malonate complexes [Ag2Ni(H2O)2(R2mal)2]n (R2mal2– is the dimethylmalonate dianion (Me2mal2–) (1) or the cyclobutane-1,1-dicarboxylate dianion...     

Syntheses,crystal structures,and magnetic properties of the banana-shaped tungstophosphates: [M6(H2O)2(PW9O34)2(PW6O26)]17− (MII=NiII,CoII)

Two new banana-shaped tungstophosphates [M₆(H₂O)₂(PW₉O₃₄)₂(PW₆O₂₆)]^{17 ?} (M^II?=?Ni^II, Co^II) incorporating two types of lacunary polyoxometalate units have been synthesized in aqueous solution and characterized by elemental analyses, IR, and UV spectra, and single-crystal X-ray diffraction. Structural analyses show that Na₆H₁₁[Ni₆(H₂O)₂(PW₉O₃₄)₂(PW₆O₂₆)]?·?32H₂O (1) and Na₇H₁₀[Co₆(H₂O)₂(PW₉O₃₄)₂(PW₆O₂₆)]?· 31H₂O (2) are generated from two tri-M^II substituted B-α-[(MOH₂)M₂PW₉O₃₄] Keggin units connected by a hexavacant [PW₆O₂₆]^11? Keggin fragment, leading to the M^II-containing banana-shaped tungstophosphates. Magnetic properties of 2 show decrease of the molar magnetic susceptibility at higher temperatures results from spin-orbit coupling of Co^II and antiferromagnetic interactions whereas the maximum at the lower temperatures is indicative of the ferromagnetic interactions within the trinuclear Co^II spin cluster in the sandwich belt.     

Isodimorphism of the salts 2RbCl · MIICl2 · 2H2O (MII = Mn,Fe, Co,Cu)

The three-component systems RbClMnCl₂H₂O, 2RbCl · CoCl₂ · 2H₂O2RbCl · CuCl₂ · 2H₂OH₂O, 2RbCl · CoCl₂ · 2H₂O2RbCl · MnCl₂ · 2H₂OH₂O have been studied at 25°C. In the 2RbCl · CoCl₂ · 2H₂O2RbCl · CuCl₂ · 2H₂OH₂O system, a discontinuous series of mixed crystals is formed and in the 2RbCl · CoCl₂ · 2H₂O2RbCl · MnCl₂ · 2H₂OH₂O system, a continuous series is present.The unit cell parameters of the 2RbCl · CoCl₂ · 2H₂O double salt were determined: a = 5.586(2) Å, b = 6.469(3) Å, c = 6.988(2) Å, α = 65.31(3)°, β = 87.69(3)°, γ = 84.65(4)°, volume 228.4 ų, Z = 1.The results obtained and discussed in conjunction with the crystal structure data suggest that for 2M^ICl · M^IICl₂ · 2H₂O type salts the triclinic structure is stable only when the large rubidium and cesium ions participate in combinations with non-Jahn-Teller metal(II) ions. In the cases of Jahn-Teller metal(II) ions or with potassium or ammonium ions a tetragonal structure is always stable.     

Synthesis, structure, and magnetic properties of heterometallic trinuclear complexes {MII��LnIII��MII} (MII = Ni, Cu; LnIII = La, Pr, Sm, Eu, Gd)

Trinuclear heterometallic complexes containing the {M₂Ln(Piv)₆(NO₃)} (M^II = Ni, Cu; Ln^III = Nd, Pr, Sm, Eu, Gd; Piv^? is the anion of pivalic acid) and {Cu₂Ln(Piv)₈)]^? (Ln^III = Eu, Gd) metal cores were synthesized, their structures and magnetic properties were studied. For the most compounds, it was shown that their magnetic properties can be interpreted taking no interaction of the 3d-metal ions and a lanthanide into account. Ferromagnetic exchange interactions were found to exist between the unpaired electrons of the paramagnetic centers in the exchange clusters of the gadolinium-containing heterometallic complexes {M-Gd-M} (M = Ni or Cu).     

Study of the state of uranoarsenates MII(AsUO6)2·nH2O(MII = Mn2+, Co2+, Ni2+, Cu2+, Zn2+, Cd2+, Pb2+) in aqueous solutions

State of uranoarsenates M^II(AsUO₆)₂·nH₂O (M^II = Mn, Co, Ni, Cu, Zn, Cd, Pb) in aqueous solutions in a wide range of acidity (pH 0?C14) was studied. Acid-base boundaries of existence of the compounds were estimated, products of conversion were identified, and solubility of M^II(AsUO₆)₂·nH₂O was determined. On the basis of the obtained data the solubility products and Gibbs functions of formation of uranoarsenates, and the solubility curves were calculated, phase diagrams of uranium(VI) and arsenic(V) in solutions and in equilibrium solid phases were constructed with the use of the equilibrium thermodynamics technique.     

Crystal Growth and Crystal Structures of Gold(V) Compounds: Cu(AuF6)2, Ag(AuF6)2, and O2(CuF)3(AuF6)4 ⋅ HF

Crystal growth from anhydrous hydrogen fluoride solutions of M²⁺ (M=Cu, Ag) and [AuF₆]⁻ gave M(AuF₆)₂ salts (M=Cu, Ag). Similar attempts to prepare single crystals of the corresponding nickel, zinc and magnesium salts failed. The crystal structure of Cu(AuF₆)₂ consists of layers of Cu²⁺ cations connected by [AuF₆]⁻ anions, thus forming slabs. Only van der Waals interactions exist between adjacent slabs. The crystal structure of Ag(AuF₆)₂ consists of a three-dimensional framework in which Ag⁺ cations are linked by [AuF₆]⁻ anions. Both structures are members of the M^II(X^VF₆)₂ family, in which seven different structure types have been observed to date. In the crystal structure of O₂(CuF)₃(AuF₆)₄ ⋅ HF, the bridging AuF₆ units connect [−Cu−F−Cu−F−]_∞ chains to form stacks between which O₂⁺ cations and HF molecules are located.     

Cyanido-bridged one-dimensional systems assembled from [ReIVCl4(CN)2]2? and [MII(cyclam)]2+ (M = Ni, Cu) precursors

Three new cyanido-bridged heterometallic Re^IVNi^II and Re^IVCu^II one-dimensional systems were synthesized and extensively characterized both structurally and magnetically. Single-crystal X-ray diffraction analysis revealed that these compounds display a common topology, with chains composed of alternating [Re^IVCl₄(CN)₂]^2? and [M^II(cyclam)]²⁺ (M = Ni in 1, Cu in 2) or [Cu^II(N,N??-dimethylcyclam)]²⁺ (in 3) building units. Two different chain orientations with a tilt angle of ca. 51° to 55° are present in the crystal packing of these compounds. The magnetic susceptibility measurements suggest the presence of intrachain ferromagnetic interactions between the S = 3/2 Re^IV centers and the 3d metal ions: S = 1 Ni^II or S = 1/2 Cu^II. At low temperature, a three-dimensional ordered magnetic phase induced by interchain antiferromagnetic interactions (antiferromagnetic for 1 and 2; canted antiferromagnetic for 3) is detected for the three compounds.     

Syntheses, X-ray structural characterizations, and thermal stabilities of two nonclassical trinuclear vanadium(IV) complexes, (V3(μ3-O)O2)(μ2-O2P(CH2C6H5)2)6(H2O) and (V3(μ3-O)O2)(μ2-O2P(CH2C6H5)2)6(py), and polymeric complexes of stoichiometry (VO(O2PR2)2)∞, R2 = Ph2 and o-(CH2)2(C6H4)

The preparation and structural characterization of two trinuclear vanadium complexes, (V(3)(μ(3)-O)O(2))(μ(2)-O(2)P(CH(2)C(6)H(5))(2))(6)(H(2)O), 1, and (V(3)(μ(3)-O)O(2))(μ(2)-O(2)P(CH(2)C(6)H(5))(2))(6)(py), 2, are reported. In these nonclassical structures, the planar central core consists of the three vanadium atoms arranged in the form of an acute quasi-isosceles triangle with the central oxygen atom multiply bonded to the vanadium atom at the center of the vertex angle and weakly interacting with the two other vanadium atoms on the base sites, each of which contain one external multiply bonded oxygen atom. Reacting VO(acac)(2)in the presence of diphenylphosphinic acid affords (VO(O(2)PPh(2))(2))(∞), 3, while 2-hydroxyisophosphindoline-2-oxide at room temperature in CH(2)Cl(2) affords ((H(2)O)VO(O(2)Po-(CH(2))(2)C(6)H(4))(2))(∞), 4, and at 120 °C in EtOH yields (VO(O(2)P(o-(CH(2))(2)(C(6)H(4)))(∞), 5 on the basis of elemental analyses. The thermal and chemical stability of the complexes were assessed by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) measurements. The bond strengths of the vanadium atoms to the OH(2) ligand in 1 and to the NC(5)H(5) ligand in 2 were assessed at 10.7 and 42.0 kJ/mol respectively. Room temperature magnetic susceptibility measurements reveal magnetic moments for trinuclear 1 and 2 at 3.02(1) and 3.05(1) μ(B/mol), and also close to spin only values (1.73 μ(B)) values for 3, 4, and 5 at 1.77(2), 1.758(7), and 1.77(3) μ(B), respectively. Variable-temperature, solid-state magnetic susceptibility measurements were conducted on complex 2 in the temperature range of 2.0-298 K and at an applied field of 0.5 T. Magnetization measurements at 2 and 4 K confirmed a very weak magnetic interaction between the vanadyl centers.     

Syntheses,crystal structures,and electrochemical studies of Fe2(CO)6(μ-PPh2)(μ-L) (L = OH,OPPh2, PPh2)

Reaction of Fe₃(CO)₁₂ and Ph₂PH in the presence of Et₃N in THF at 0?°C immediately forms Fe₂(CO)₆(μ-PPh₂)(μ-OH) (1), Fe₂(CO)₆(μ-PPh₂)(μ-k²O,P-OPPh₂) (2), and Fe₂(CO)₆(μ-PPh₂)₂ (3) in yields of 25, 14, and 19%, respectively. Experiments confirm that Et₃N shortens the reaction time. The absence of O₂ hinders the formation of 2. The presence of H₂O can increase the yield of 1. Their structures have been determined by X-ray crystallography and the complexes have been completely characterized by EA, IR, and ¹H, ¹³C, ³¹P NMR. Electrochemical studies reveal that they exhibit catalytic H₂-producing activities.     

Asymmetric Synthesis of (-)-(2R,3R,6S)-Irnigaine

Introduction　　Asarelativelynewmemberofnaturalalkaloidswith2 ,6 disubstituted 3 piperidinolskeleton ,irnigaine 1wasisolatedfromthetubersofArisarumVulgare (Araceae)in1995byMelhaouiandBode .1Itsstructureandrelativeconfigurationswereelucidatedby1HNMRstudiesandtheabsoluteconfigurationwasproposedonthebasisofitsopti calrotation .1Soonafterthen ,Meyerandhisco workersreportedthefirstsynthesisof (- ) (2R ,3R ,6S) irni gaineandtheconfigurationconfirmation .Althoughtheirsynthesisroutewasshortan…     

Die Kristallstrukturen von β-TaNi3, Ta(Cu,Al)2, Nb(Cu,Al)2 und Ta6(Cu,Al)7

Zusammenfassung Neben der bekannten Phase TaNi₃ mit TiCu₃-Typ wird eine Kristallart gleicher Zusammensetzung gefunden, die mit TiAl₃ isotyp ist. Ta(Cu, Al)₂ und Nb(Cu, Al)₂ kristallisieren im MgZn₂-Typ (Laves-Phase). Ta₆(Cu, Al)₇ ist eine -Phase.     

Tieftemperatur-flüssigphasefluorierung von pentafluorphenyl-element-Verbindungen. Darstellungen und eigenschaften von (C6F5)3AsF2, (C6F5)3SbF2, (C6F5)2SeF2, (C6F5)2SeO,C6F5TeF3 und Cs[(C6F5)3EF3] (E = As,Sb) [1]

The fluorination reactions of (C₆F₅)₃E (E = As, Sb) with elemental flourine yield (C₆F₅)₃EF₂ in high yields. From the reactions of (C₆F₅)₃EF₂ with CsF the new salts Cs[(C₆F₅)₃EF₃] are obtained. (C₆F₅)₂SeF₂ and C₆F₅TeF₃ are formed for the first time by reacting (C₆F₅)₂SeF and (C₆F₅)₂TeF₂ with elemental flourine and XeF₂, respectively. (C₆F₅)₂SeF₂ rapidly reacts with glass, and the new compound (C₆F₅)₂SeO is isolated. The preparations, properties and ¹⁹F NMR spectra of the new compounds are described.     

An absolute integrated infrared intensity study of (η6C6H5R)Cr(CO)2(CS) (R = H,Me, Cl,CO2Me)

The absolute integrated i.r. intensities of the CO and CS stretching bands of the thiocarbonyl complexes (η⁶C₆H₅R)Cr(CO)₂(CS), where R = H, Me, Cl and CO₂Me, have been determined in CS₂ solutions. The intensities have been correlated with each other and with the band wavenumbers, and have been shown to be dependent on the nature of the substituent R in the aromatic ring. The intensities have been demonstrated to be better probes of the electronic effects occurring in these complexes than are the wavenumbers, and correlate well with the Hammett substituent parameters, σ⁰.     

Spin-glass state in Ni5(OH)6(CnH2n−4O4)2 metal-organic frameworks (n = 6, 8, 10, 12)

We present an extension of a previously published work (J. Solid State Chem. 181 (2008) 3229) concerning Metal-Organic Frameworks (MOFs) of general formula Ni₅(OH)₆(C_nH_2n−4O₄)₂. A modified synthesis procedure comprising a room-temperature step prior to the hydrothermal treatment was employed. This preliminary step made use of peristaltic pumps allowing slow mixing of the reactants at a constant pH value. Samples of better purity and crystallinity were consequently obtained. In particular, the better crystallinity allowed us to work on two other members of the series, n = 10 and n = 12, which were characterized using synchrotron powder X-ray powder diffraction. These two compounds are isoreticular with the n = 6 and n = 8 compounds previously reported. The crystal structure incorporates the long alkane dioic acid molecules as pillars between complex inorganic layers. Samples of better purity for n = 6 and 8, as well as those of the new compounds with n = 10 and 12, gave us the opportunity to revise the magnetic properties of these MOFs. We found similar magnetic behaviors, independently of the interlayer spacing. We show that, below 19 K, these materials most probably enter a spin-glass or cluster spin-glass state rather than a three-dimensionally long-range ordered state. We link this behavior to the complex topology of the magnetic exchange interactions within the inorganic layers which is very likely to be source of magnetic frustration.     

Crystal structure of CsLnFe(CN)6·5H2O (Ln=Ce,Pr, Nd), CsCeFe(CN)6·4H2O,and TlTmRu(CN)6·3H2O

We have investigated the crystal structures of CsLnFe(CN)₆·nH₂O (Ln=lanthanide, n=4,5), as well as TlTmRu(CN)₆·3H₂O. These phases can be thought of as derivatives of LnFe(CN)₆·4H₂O, where, simultaneously, an alkali ion (or Tl⁺) is introduced while the valence of Fe is reduced from Fe³⁺ to Fe²⁺. A new arrangement of the structural units is observed in the CsLnFe(CN)₆·5H₂O, where the coordination of the Ln-ion is changed to a bisdisphenoid. The resulting LnN₅O₃ units alternate with Fe(CN)₆ units to form an overall rocksalt-type ralted lattice that accommodates the alkali ions in interstitial sites. Due to the arrangement of the water molecules, a layer structure results.