Carboxylate clusters with the M<Subscript>4</Subscript>O<Subscript>4</Subscript> cubane-like core: pivalate cocrystal containing Co<Superscript>II</Superscript> and Ni<Superscript>II</Superscript>

Joint thermolysis of the dinuclear pivalate complexes M₂(μ-H₂O)(μ-Piv)₂(Piv)₂(HPiv)₄ (M = Co (1) and Ni (2), Piv^- is the pivalate anion), in decane at 174 °C at the reactant ratio 1: 1 followed by treatment of the dry thermolysis product with methanol afforded crystals of a new cocrystallization product of the molecules containing the heterometallic cubane-like core M₄(Co,Ni)O₄. According to the X-ray diffraction data and the results of magnetic measurements, inductively coupled plasma atomic emission spectrometry (ICP-AES), and investigations of the solid-state thermal decomposition products, the isolated cocrystallization product has the general formula [Co_1.6Ni_2.4(μ₃-OMe)₄(μ₂-Piv)₂(pg² -Piv)₂(MeOH)₄] ·4MeOH (3·4MeOH). Thermolysis of the crystals of the solvate 3·4MeOH is a destructive process accompanied by the intramolecular redox reaction. A mixture of metallic Ni and cobalt oxide (CoO) are the final solid decomposition products of 3 · 4MeOH in an argon atmosphere, whereas a mixture of the phases NiO, Co₃O₄, and NiCo₂O₄ is formed in air.     

X-ray diffraction study of [M<Superscript>I</Superscript>(NH<Subscript>3</Subscript>)<Subscript>5</Subscript>Cl] [M<Superscript>II</Superscript>Br<Subscript>6</Subscript>] (M<Superscript>I</Superscript> = Rh,Ir; M<Superscript>II</Superscript> = Re,Ir) polycrystals

Based on the X-ray diffraction data for polycrystals, the crystal structures of double complex salts [Rh(NH₃)₅Cl][ReBr₆] and [Ir(NH₃)₅Cl][ReBr₆] are refined. The structure of [Rh(NH₃)₅Cl][IrBr₆] is determined. Initial models are constructed using the Monte Carlo method in the straight space. Further refinement is made by the Rietveld method. It is shown that such an approach is suitable for the refinement of crystal structures composed of isolated rigid polyhedra and can be used to determine the structure of salts without structural analogues     

Complex amidoboranes M<Superscript>2</Superscript>[M<Superscript>1</Superscript>(NH<Subscript>2</Subscript>BH<Subscript>3</Subscript>)<Subscript>4</Subscript>] (M<Superscript>1</Superscript> = Al,Ga; M<Superscript>2</Superscript> = Li,Na, K,Rb, Cs)

Structural, spectral, and thermodynamic characteristics of complex amidoboranes M²[M¹(NH₂BH₃)₄] (M¹ = Al, Ga; M² = Li, Na, K, Rb, Cs) were calculated by the B3LYP/def2-SVPD quantum-chemical method. The procedure for the synthesis of these compounds by reactions of alkali metal amidoboranes with aluminum and gallium chlorides was suggested and experimentally tested. Reaction products were characterized by the NMR and IR spectroscopy and X-ray phase analysis.     

La<Subscript>2</Subscript>M<Stack><Subscript>3</Subscript><Superscript>II</Superscript></Stack>Mn<Subscript>4</Subscript>O<Subscript>12</Subscript> (M = Mg,Ca, Sr,or Ba) manganites: Synthesis and X-ray diffraction study

La₂M ₃ ^II Mn₄O₁₂ (M = Mg, Ca, Sr, or Ba) manganites have been synthesized by ceramic technology from lanthanum oxide, manganese(III) oxide, and magnesium, calcium, strontium, or barium carbonate. X-ray powder diffraction shows that these compounds crystallize in cubic perovskite space group Pm3m.     

Crystal structure of M<Superscript>I</Superscript>VWO<Subscript>6</Subscript> (M = Li,Na) compounds

Compounds of the composition M^IVWO₆ (M = Li, Na) were prepared by solid-phase synthesis at 600°C. The compounds crystallize in the mineral brannerite structure type. The sodium derivative was prepared and identified for the first time. The crystal structures of the compounds were refined by the Rietveld method (space group C2/m).     

Phase transitions in double molybdates K<Subscript>2</Subscript>M<Stack><Subscript>2</Subscript><Superscript>II</Superscript></Stack>(MoO<Subscript>4</Subscript>)<Subscript>3</Subscript> with M = Mg or Co

Phase transitions and cation mobility in double molybdates K₂M ₂ ^II (MoO₄)₃ with M = Mg or Co and the products of their heterovalent doping with scandium(III) and vanadium(V) have been studied. The transition from low to high conductivity in K₂M ₂ ^II (MoO₄)₃ is the result of a two-stage phase transition, whose occurrence is significantly extended in time. Heterovalent substitutions noticeably decrease the heat of the phase transition. The transition to the low-temperature phase is not achieved even after long-term exposure.     

Paramagnetic properties of triple molybdates CsNa<Subscript>5</Subscript>M<Subscript>3</Subscript>(MoO<Subscript>4</Subscript>)<Subscript>6</Subscript> (M = Ni,Co, Mn)

The static magnetization of CsNa₅M₃(MoO₄)₆ single phase molybdates, where M = Co, Ni, and Mn, is measured at 4–300 K in magnetic fields of up to 20 kOe. It is shown that the materials are paramagnetic. Magnetization as a function of temperature is described using the Curie–Weiss law. The intrinsic magnetic moments of the phases are found to be 9.759 (Co), 6.958 (Ni), and 12.203 Bohr magnetons for manganese molybdates. It is concluded that the charge state of Co, Ni, and Mn cations in the compounds is +2.     

Synthesis,crystal structure,and vibrational spectra of M<Subscript>4</Subscript>V<Subscript>2</Subscript>O<Subscript>3</Subscript>(SO<Subscript>4</Subscript>)<Subscript>4</Subscript> (M = K,Rb, Cs)

Synthesis was performed and physicochemical properties were studied for the M₄V₂O₃(SO₄)₄ complexes, where M = K, Rb, or Cs. Their crystal structures were determined using the set of data from X-ray diffraction and neutron diffraction studies. All compounds crystallize in a triclinic lattice (space group \(P\bar 1\), Z = 2) with the parameters: a = 7.7688(2), 7.8487(1), 8.1234(1) Å; b = 10.4918(3), 10.8750(2), 11.1065(1) Å; c = 11.9783(4), 12.1336(2), and 11.8039(1) Å; α = 76.600(2)°, 77.910(1)°, 79.589(1)°; β = 75.133(2)°, 75.718(1)°, 87.939(1)°; γ = 71.285(2)°, 72.189(1)°, 75.567(1)°; V = 881.78(5), 945.42(3), 1014.34(2) ų for K, Rb, Cs, respectively. The structure of M₄V₂O₃(SO₄)₄ was found to be formed by discrete complex anions V₂O₃(SO₄) ₄ ^4? incorporating two oxygen-bridged vanadium atoms in a distorted octahedral oxygen environment. The sulfate groups are coordinated by the vanadium atoms in the chelating mode with a large scatter of S-O interatomic distances and OSO angles. Every VO₆ octahedron has a short terminal vanadium-oxygen bond with a length of about 1.6Å. The V₂O₃(SO₄) ₄ ^4? complex anions in potassium and rubidium compounds differ from that in Cs₄V₂O₃(SO₄)₄ in the type of symmetry and mutual spatial orientation. The vibrational spectra were presented and interpreted in line with the structural analysis data.     

Synthesis,structures, and physicochemical properties of Sr<Subscript>2</Subscript>A<Superscript>II</Superscript>UO<Subscript>6</Subscript> (A<Superscript>II</Superscript> = Mg,Ca, Sr,Ba, Mn,Fe, Co,Ni, Zn,and Cd) compounds

Sr₂A^IIUO₆ (A^II = Mg, Ca, Sr, Ba, Mn, Fe, Co, Ni, Zn, and Cd) compounds were synthesized by high-temperature reactions in the solid phase. The crystal structure (space group P2₁/n) was refined by the Rietveld method for Sr₂MgUO₆, (Sr_0.5Ba_0.5)₂SrUO₄, and Sr₂CdUO₆, which were synthesized for the first time. IR spectral characteristics were studied. The standard enthalpies of formation of the compounds were determined by reaction calorimetry.     

Cubane pyridine-acetylacetonate cluster complexes with the M<Subscript>3</Subscript>CuS<Stack><Subscript>4</Subscript><Superscript>5+</Superscript></Stack> core (M = Mo,W)

The reactions between [Mo₃(μ₃-S)(μ₂-S)₃(Acac)₃(Py)₃]PF₆ (HAcac is acetylacetone, Py is pyridine) and CuX (X = Cl, I, SCN) afford heterometallic cubane clusters [Mo₃(CuX)(μ₃-S)₄(Acac)₃(Py)₃]PF₆. The structures of two new compounds, [Mo₃(CuCl)S₄(Acac)₃(Py)₃]PF₆ · 3.25CH₂Cl₂ · 0.5C₆H₅CH₃ and [Mo₃(CuI)S₄(Acac)₃(Py)₃]PF₆ · 4C₆H₆, are determined by X-ray diffraction analysis. All synthesized compounds are characterized by elemental analysis and IR spectra. According to the vibrational spectra, the thiocyanate complex in the solid state is a mixture of the bond isomers [Mo₃(CuNCS)S₄(Acac)₃(Py)₃]PF₆ and [Mo₃(CuSCN)S₄(Acac)₃(Py)₃]PF₆, whereas in solution this complex exists as a isothiocyanate form.     

Quantum-chemical modeling of the electronic structure and chemical bond of Sn<Subscript>0.875</Subscript>M<Subscript>0.125</Subscript>O<Subscript>2</Subscript> (M = Cr,Mn, Co)

The electronic structure of the Sn_0.875M_0.125O₂ compounds (M = Cr, Mn, Co) with a rutile structure and magnetic moments of the transition metal atoms in them were calculated by the ab initio spin-polarized linear muffin-tin orbital method. The electron density and electron localization function maps for these compounds were constructed. Based on these data, the effect of the composition of these phases on the electronic spectrum, chemical bond, and magnetic and transport properties were analyzed.     

Supramolecular architecture of the [M(1-MeIm)<Subscript>2</Subscript>(H<Subscript>2</Subscript>O)<Subscript>4</Subscript>]<Superscript>2+</Superscript> (M = Ni,Co) complexes with the terephthalate anion

The [M(1-MeIm)₂(H₂O)₄](Tpht) · 4H₂O complexes (where M = Ni, Co; 1-MeIm is 1-methylimidazole; H₂Tpht is terephthalic acid) are synthesized and characterized by X-ray diffraction analysis. The ionic structure is built of the [M(1-MeIm)₂(H₂O)₄]²⁺ cations and (Tpht)^2? anions. The metal ions have a distorted octahedral coordination. The cations and anions are united by hydrogen bonding system.     

Complexation of Zn<Subscript>2</Subscript>[Fe(CN)<Subscript>6</Subscript>] with M<Superscript>2+</Superscript> (M = Mn,Co, Ni,Cu, Cd) in Zn<Subscript>2</Subscript>[Fe(CN)<Subscript>6</Subscript>] gelatin-immobilized matrices

Electrophilic substitution reactions Zn²⁺ M²⁺ (M = Mn, Co, Ni, Cu, Cd) in thin gelatin layers with immobilized zinc(II) hexacyanoferrate brought in contact with the aqueous solutions of d-element chlorides are studied. In all cases (except for Mn(II)), Zn atoms are partially replaced by all metals in question with the formation of the corresponding binuclear ZnM hexacyanoferrates(II). No complete replacement of Zn(II) to mononuclear hexacyanoferrate(II) of substituting metal occurs in neither of the cases.Translated from Koordinatsionnaya Khimiya, Vol. 31, No. 2, 2005, pp. 110–116. Original Russian Text Copyright © 2005 by Tatarintseva, Mikhailov, Naumkina, Lygina.     

Synthesis,structure, and properties of M<Subscript>3</Subscript>VO<Subscript>2</Subscript>(SO<Subscript>4</Subscript>)<Subscript>2</Subscript> (M = Rb,Cs)

Vanadium(V) complexes of general composition M₃VO₂(SO₄)₂ (M = Rb, Cs) were synthesized by a solid-state route. The individuality of the synthesized compounds was proved by X-ray and neutron diffraction, vibrational spectroscopy, and microscopic analysis. The X-ray diffraction patterns of M₃VO₂(SO₄)₂ were indexed to fit the monoclinic system (space group P2/c, Z = 4) with the following unit cell parameters: a = 11.6487(2) Å, b = 8.4469(2) Å, c = 12.1110(2) Å, β = 109.483(1)°, V = 1123.43 ų (Rb); a = 12.0546(3) Å b = 8.7706(2) Å, c = 12.6496(3) Å, β = 109.843(2)°, V = 1257.99 ų (Cs). In the crystal structure of M₃VO₂(SO₄)₂, [VO₂(SO₄)₂]^3? complex anions can be discerned in which the vanadium atom is surrounded by five oxygen atoms: two oxygen atoms form short terminal V–O bonds, and three oxygen atoms are from the two sulfato groups, one of which acts as a monodentate ligand and the other acts as a bidentate chelating ligand.     

Manganites NdMg<Stack><Subscript>3</Subscript><Superscript>I</Superscript></Stack>Mg<Subscript>3</Subscript>Mn<Subscript>4</Subscript>O<Subscript>12</Subscript> (M<Superscript>I</Superscript> = Li,Na, K): X-ray diffraction data

NdLi₃Mg₃Mn₄O₁₂, NdNa₃Mg₃Mn₄O₁₂, and NdK₃Mg₃Mn₄O₁₂ manganites were synthesized for the first time by solid phase reactions of neodymium(III) and manganese(III) oxides with lithium, sodium, potassium, and magnesium carbonates. X-ray diffraction showed that the compounds crystallized in the tetragonal crystal system. Their unit cell parameters were determined.     

Isomerization of silicenium and germenium ions in the systems C<Subscript>4</Subscript>H<Subscript>11</Subscript>M<Superscript>+</Superscript> (M = Si,Ge)

Equilibrium structures of the isomers and transition states of their interconversion in the system C₄H₁₁M⁺ (M = Si, Ge) have been obtained at theB3LYP level of theory using the cc-pVTZ basis set. The structures of these stationary points are close for Si and Ge; the most stable isomer in both systems is the tertiary cation (C₂H₅)(CH₃)₂M⁺, the second in energy is complex with ethylene [(CH₃)₂HM·C₂H₄]⁺. The secondary cation (C₂H₅)₂HM⁺ is third in energy isomer, the height of the barrier of interconversion for these three cations being practically independent on M. However, for M = Ge a substantial decrease in the energy of isomeric forms corresponding to complexes with alkanes is observed. As a result, in the system C₄H₁₁Ge⁺ the fourth in energy is isomer [(C₂H₅)Ge·C₂H₆]⁺ rather than [(C₂H₅)H₂Ge·C₂H₄]⁺ as for M = Si. Nevertheless, the height of the barriers for transition into these structures, although decreasing from M = Si to Ge, remain rather high, and the most favorable route of decomposition in both systems is the elimination of ethylene.     

Reactivity of triangular oxalate cluster complexes [M<Subscript>3</Subscript>Q<Subscript>7</Subscript>(C<Subscript>2</Subscript>O<Subscript>4</Subscript>)<Subscript>3</Subscript>]<Superscript>2−</Superscript> (M = Mo or W; Q = S or Se)

The reactions of the oxalate complexes [M₃Q₇(C₂O₄)₃]²⁻ (M = Mo or W; Q = S or Se) with Mn^II, Co^II, Ni^II, and Cu^II aqua and ethylenediamine complexes in aqueous and aqueous ethanolic solutions were studied. The previously unknown heterometallic complexes [Mo₃Se₇(C₂O₄)₃Ni(H₂O)₅]·3.5H₂O (1) and K₃{[Cu(en)₂H₂O]([Mo₃S₇(ox)₃]₂Br)}·5.5H₂O (2) were synthesized. In these complexes, the oxalate clusters serve as monodentate ligands. The K(H₂en)₂[W₃S₇(C₂O₄)₃]₂Br·4H₂O salt (3) was isolated from solutions containing Co^II, Ni^II, or Cu^II aqua complexes and ethylenediamine. The reaction of [Mo₃Se₇(C₂O₄)₃]²⁻ with HBr produced the bromide complex [Mo₃Se₇Br₆]²⁻, which was isolated as (Bu₄N)₂[Mo₃Se₇Br₆] (4). Complexes 1–3 were characterized by X-ray diffraction, IR spectra, and elemental analysis. The formation of 4 was detected by electrospray mass spectrometry. Dedicated to Academician G. A. Abakumov on the occasion of his 70th birthday. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1645–1649, September, 2007.     

Cuboidal oxalate cluster complexes with the Mo<Subscript>3</Subscript>CuQ<Subscript>4</Subscript><Superscript>5+</Superscript> cluster core (Q = S or Se): synthesis,structure, and electrochemical properties

The reactions of the [Mo₃(μ₃-Q)(μ₂-Q)₃(H₂O)₃(C₂O₄)₃]²⁻ complex (Q = S or Se) with CuX salts (X = Cl, Br, I, or SCN) in water produce the cuboidal heterometallic clusters [Mo₃(CuX)(μ₃-Q)₄(H₂O)₃(C₂O₄)₃]²⁻, which were isolated as the potassium and tetraphenylphosphonium salts. Two new compounds, K₂[Mo₃(CuI)(μ₃-S)₄(H₂O)₃(C₂O₄)₃]·6H₂O and (PPh₄)₂[Mo₃(CuBr)(μ₃-S)₄(H₂O)₃(C₂O₄)₃]·7H₂O, were structurally characterized. All compounds were characterized by elemental analysis and IR spectroscopy. The K₂[Mo₃(CuI)(μ₃-Se)₄(H₂O)₃(C₂O₄)₃] compound was characterized by the ⁷⁷Se NMR spectrum; the (PPh₄)₂[Mo₃(CuI)(μ₃-S)₄(H₂O)₃(C₂O₄)₃], (PPh₄)₂[Mo₃(CuI)(μ₃-Se)₄(H₂O)₃(C₂O₄)₃] and K₂[Mo₃(CuSCN)(μ₃-S)₄(H₂O)₃(C₂O₄)₃]·7H₂O compounds, by electrospray mass spectra. Dedicated to Academician G. A. Abakumov on the occasion of his 70th birthday. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1639–1644, September, 2007.     

Synthesis and X-ray diffraction study of ferrites ErM<Superscript>I</Superscript>Fe<Subscript>2</Subscript>O<Subscript>5</Subscript> (M<Superscript>I</Superscript> = Li,Na, K,Cs)

Ferrites of composition ErM^IFe₂O₅ (M^I = Li, Na, K, Cs) were synthesized by a solid-phase method. The structure of the ferrites was for the first time studied by X-ray powder diffraction. Crystal systems, unit cell parameters, and X-ray and pycnometric densities were determined. For ErLiFe₂O₅, a = 10.510 Å, c = 14.270 Å, V°= 1616.16 ų, Z = 16, V _subcell ^° = 101.01 ų, ρ_x = 6.01 g/cm³, ρ_pyc = 5.97 ± 0.04 g/cm³; for ErNaFe₂O₅, a = 10.519 Å, c = 15.510 Å, V° = 1759.56 ų, Z = 16, V _subcell ^° = 109.90 ų, ρ_x = 5.77 g/cm³, ρ_pyc = 5.72 ± 0.08 g/cm³; for ErKFe₂O₅, a = 11.050 Å, c = 15.480 Å, V° = 1937.33 ų, Z = 16, V _subcell ^° = 121.08 ų, ρ_x = 5.46 g/cm³, ρ_pyc = 5.41 ± 0.04 g/cm³; and for ErCsFe₂O₅, a = 10.78 Å, c = 16.01 Å, V° = 1905.37 ų, Z = 16, V _subcell ^° = 119.09 ų, ρ_x = 6.86 g/cm³, ρ_pyc = 6.61 ± 0.01 g/cm³.