Synthesis and transformations of metallacycles 33. The first example of cycloalumination of cyclonona-1,2-diene with Et<Subscript>3</Subscript>Al and EtAlCl<Subscript>2</Subscript> in the presence of Cp<Subscript>2</Subscript>ZrCl<Subscript>2</Subscript>

Catalytic cycloalumination of cyclonona-1,2-diene upon treatment with Et₃Al and EtAlCl₂ in the presence of Cp₂ZrCl₂, leading to 10-ethyl-10-aluminabicyclo[7.3.0^1,9]dodec-8-ene (1) and 11-ethyl-11-aluminatricyclo[10.7.0^1,12.0^2,10]nonadeca-9,12-diene, respectively, was accomplished in high yields. A possibility for the selective transformation of compound 1 to 1-allyl-9-(pent-4-enyl)cyclonon-1-ene and 10-hydroxybicyclo[7.3.0^1,9]dodec-8-ene in one preparative step was demonstrated. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2156–2159, November, 2007.     

Subsolidus phase diagrams for the Tl<Subscript>2</Subscript>MoO<Subscript>4</Subscript>-Ln<Subscript>2</Subscript>(MoO<Subscript>4</Subscript>)<Subscript>3</Subscript>-Hf(MoO<Subscript>4</Subscript>)<Subscript>2</Subscript> systems,where Ln = La-Lu

The Tl₂MoO₄-Ln₂(MoO₄)₃-Hf(MoO₄)₂ systems where Ln = La-Lu were studied in the subsolidus region using X-ray powder diffraction. Quasi-binary joins were revealed, and triangulation carried out. New ternary molybdates were prepared: Tl₅LnHf(MoO₄)₆ (5: 1: 2) for Ln = Ce-Ho, Tl₅LnHf(MoO₄)₆ (5: 1: 2) for Ln = Er-Lu, TlLnHf_0.5(MoO₄)₃ (1: 1: 1) for Ln = Ce-Nd, and Tl₂LnHf₂(MoO₄)_6.5 (2: 1: 4) for Ln = Ce-Lu. The crystallographic parameters of Tl₅LnHf(MoO₄)₆ (5: 1: 2) compounds for Ln = Er-Lu were determined.     

Organic-inorganic hybrid perovskite (C<Subscript>6</Subscript>H<Subscript>5</Subscript>(CH<Subscript>2</Subscript>)<Subscript>2</Subscript>NH<Subscript>3</Subscript>)<Subscript>2</Subscript>CdCl<Subscript>4</Subscript>: Synthesis,structural and thermal properties

The present research work reports the study on crystal structure, vibrational spectroscopy and thermal analysis of organic-inorganic hybrid compound (C₆H₅(CH₂)₂NH₃)₂CdCl₄. Single crystals of bis(phenethylammonium)tetrachlorocadmate (C₆H₅(CH₂)₂NH₃)₂CdCl₄ (PEA–Cd) were obtained by diffusion at room temperature. This compound crystallizes in the orthorhombic space group C2cb with unit cell parameters a = 7.4444(2) Å, b = 38.8965(3) Å, c = 7.3737(2) Å and Z = 4. Single crystal structure has been solved and refined to R = 0.036 and wR = 0.092. The structure consists of an extended [CdCl₄]^2– network and two [C₆H₅(CH₂)₂NH₃]⁺ cations to form a two-dimensional perovskite system. The infrared (IR) spectrum of the title compound was recorded at room temperature. Differential scanning calorimetry (DSC) was used to investigate the phase transition; this compound exhibits a reversible single solid-solid phase transition.     

Synthesis,characterization, and biphasic ionic liquid media 1-hexene hydrogenation reaction of RuCl<Subscript>2</Subscript>(DMSO)<Subscript>2</Subscript>(NC<Subscript>5</Subscript>H<Subscript>4</Subscript>CO<Subscript>2</Subscript>Na-3)<Subscript>2</Subscript>

RuCl₂(DMSO)₂(NC₅H₄CO₂Na-3)₂ is very soluble in the ionic liquid (IL) 1-n-butyl-3-methylimidazolium tetrafluoroborate, [(BMIM)BF₄]. The complex was prepared by reacting RuCl₂(DMSO)₄ with NC₅H₄CO₂Na-3, sodium nicotinate, in toluene, and was characterized by spectroscopic methods. The complex catalyzes the hydrogenation of 1-hexene (600 psi H₂, 100 °C) in a two-phase system consisting of cyclohexane/[(BMIM)BF₄] with 75% conversion in 24 h and modest substrate isomerization. The complex shows good stability and can be reused several times with little loss in activity.     

Phase equilibria in the Ce<Subscript>2</Subscript>O<Subscript>3</Subscript>-K<Subscript>2</Subscript>O-P<Subscript>2</Subscript>O<Subscript>5</Subscript> system

Ce₂O₃-K₂O-P₂O₅ ternary system has been investigated by thermoanalytical methods (DTA, DSC), powder X-ray diffraction, XPS and IR spectroscopy. The existence of three double potassium-cerium(III) phosphates has been confirmed and a new binary phosphate K₄Ce₂P₄O₁₅ has been found. Phase diagram and isothermal section at room temperature of the system Ce₂O₃-K₂O-P₂O₅ have been presented.     

Phase formation in the V<Subscript>2</Subscript>O<Subscript>5</Subscript>-Ta<Subscript>2</Subscript>O<Subscript>5</Subscript>-MoO<Subscript>3</Subscript> system

Solid-phase interactions in the V₂O₅-Ta₂O₅-MoO₃ system were studied. The formation of com- pounds TaVO₅ and VTa₉O₂₅ in the V₂O₅-Ta₂O₅ binary system was verified. Tetragonal VTa₉O₂₅-base solid solutions of the general formula Ta_{5 + 4x} V_{5 − 4x} O₂₅ (x = 0.25–1) and TaVO₅-base solid solutions of the general formula Ta _x Mo_{1 − x} V_{2 − x} O_{8 − 3x} (x = 0.625–1) were found to form. Subsolidus phase equilibria in the V₂O₅-Ta₂O₅-MoO₃ were determined.     

Phase formation in the Ag<Subscript>2</Subscript>MoO<Subscript>4</Subscript>-MgMoO<Subscript>4</Subscript>-Al<Subscript>2</Subscript>(MoO<Subscript>4</Subscript>)<Subscript>3</Subscript> system

The subsolidus region of the Ag₂MoO₄-MgMoO₄-Al₂(MoO₄)₃ ternary salt system has been studied by X-ray phase analysis. The formation of new compounds Ag_{1 ? x} Mg_{1 ? x} Al_{1 + x} (MoO₄)₃ (0 ≤ x ≤ 0.4) and AgMg₃Al(MoO₄)₅ has been determined. The Ag_{1 ? x} Mg_{1 ? x} Al_{1 + x} (MoO₄)₃ variable-composition phase is related to the NASICON type structure (space group R \(\bar 3\) c). AgMg₃Al(MoO₄)₅ is isostructural to sodium magnesium indium molybdate of the same formula unit and crystallizes in triclinic system (space group P \(\bar 1\), Z = 2) with the following unit cell parameters: a = 9.295(7) Å, b = 17.619(2) Å, c = 6.8570(7) Å, α = 87.420(9)°, β = 101.109(9)°, γ = 91.847(9)°. The compounds Ag_{1 ? x} Mg_{1 ? x} Al_{1 + x} (MoO₄)₃ and AgMg₃Al(MoO₄)₅ are thermally stable up to 790 and 820°C, respectively.     

Solid Solutions of the System V<Subscript>2</Subscript>O<Subscript>5</Subscript>-V<Subscript>2</Subscript>O<Subscript>4</Subscript>-TiO<Subscript>2</Subscript> in Air

Gravimetry in combination with X-ray phase analysis, X-ray crystallography, and X-ray densitometry were used to determine the contents of V⁵⁺, V⁴⁺, and Ti⁴⁺ ions and vacancies in solid solutions formed by the reaction of V₂O₅ with TiO₂ in air at atmospheric pressure.     

Structure of heteroassociates formed in the HF-(C<Subscript>2</Subscript>H<Subscript>5</Subscript>)<Subscript>2</Subscript>O liquid system

The aim of this work was to determine the structure of stable heteroassociates (HAs) with the stoichiometric ratios 1:2, 2:1, and 4:1 of molecules formed in the HF-(C₂H₅)₂O binary liquid system. The stretching frequencies of HF molecules found for each HA using a special procedure for processing IR spectra were compared with the calculated frequencies V HF of the stable molecular complexes (HF)_m ((C₂H₅)₂O)_n (m = 1, 2, 4, 8; n = 1, 2) with different topologies by the density functional method (B3LYP/6-31++G(d,p)). As a result, it was shown that the most stable (among H-bonded complexes with the same stoichiometric ratio of molecules) HAs HF((C₂H₅)₂O)₂, (HF)₄ ((C₂H₅)₂O)₂, and (HF)₈-((C₂H₅)₂O)₂ formed in HF solutions in diethyl ether. All of them had a cyclic structure and a common peculiarity of structure: only one lone electron pair of the oxygen atom of the (C₂H₅)₂O molecules is involved in hydrogen bonding.     

Structure and some properties of [UO<Subscript>2</Subscript>(SeO<Subscript>4</Subscript>)(C<Subscript>5</Subscript>H<Subscript>12</Subscript>N<Subscript>2</Subscript>O)<Subscript>2</Subscript>(H<Subscript>2</Subscript>O)]

The complex [UO₂(SeO₄)(C₅H₁₂N₂O)₂(H₂O)] (I) was synthesized and studied by thermal analysis, IR spectroscopy, and X-ray crystallography. The crystals are orthorhombic: a = 13.1661(3) Å, b = 16.4420(5) Å, c = 17.4548(6) Å, Pbca, Z = 8, R = 0.0423. The structural units of crystal I are chains with the composition coinciding with that of the compounds of the AB₂M ₃ ¹ crystal chemical group of the uranyl complexes (A = UO ₂ ²⁺ , B² = SeO ₄ ^2? , M¹ = C₅H₁₂N₂O and H₂O).     

Crystal Structure Of [Au(Dien)Cl]<Subscript>2</Subscript>[Re<Subscript>4</Subscript>Te<Subscript>4</Subscript>(Cn)<Subscript>12</Subscript>]Sd5H<Subscript>2</Subscript>O

The structure of the [Au(Dien)Cl]₂[Re₄Te₄(CN)₁₂]·5H₂O compound prepared in an aqueous medium by the reaction of a gold(III) complex [Au(Dien)Cl]Cl₂ with a tetranuclear tetrahedral tellurocyanide cluster complex of rhenium K₄[Re₄Te₄(CN)₁₂]·5H₂O is determined by single crystal X-ray diffraction.     

Iron(II) complexes [Fe(DfgH)<Subscript>2</Subscript>(3-CONH<Subscript>2</Subscript>-Py)<Subscript>2</Subscript>] and [Fe(DfgH)<Subscript>2</Subscript>(4-COOC<Subscript>2</Subscript>H<Subscript>5</Subscript>-Py)<Subscript>2</Subscript>]: Synthesis and structures

The complexes [Fe(DfgH)₂(3-CONH₂-Py)₂] (I) and [Fe(DfgH)₂(4-COOC₂H₅-Py)₂] (II), where DfgH₂ is α-benzyl dioxime, were obtained and examined by X-ray diffraction analysis. The equatorial planes of the coordination octahedra of the metal ions consist of two monodeprotonated α-benzyl dioxime residues united through intramolecular hydrogen bonds O-H…O into a pseudomacrocyclic system. The neutral molecules 3-CONH₂-Py and 4-COOC₂H₅-Py are coordinated to the Fe²⁺ ion through the N atom of the heterocycle. Structure I is layered and structure II is molecular. Intermolecular interactions N-H…O are responsible for the formation of layers in crystal structure I.     

Three-component systems LiBr-LiVO<Subscript>3</Subscript>-Li<Subscript>2</Subscript>MoO<Subscript>4</Subscript> and LiBr-Li<Subscript>2</Subscript>SO<Subscript>4</Subscript>-Li<Subscript>2</Subscript>MoO<Subscript>4</Subscript>

Phase equilibria in the three-component systems LiBr-LiVO₃-Li₂MoO₄ and LiBr-Li₂SO₄-Li₂MoO₄ have been studied using differential thermal analysis (DTA). Eutectic compositions have been determined (mol %): in the system LiBr-LiVO₃-Li₂MoO₄, 56.0 LiBr, 22.0 LiVO₃, and 22.0 Li₂MoO₄ with a melting temperature of 413°C; and in the system LiBr-Li₂SO₄-Li₂MoO₄, 65.0 LiBr, 14.0 Li₂SO₄, and 21.0 Li₂MoO₄ with a melting temperature of 421°C. Phase fields have been demarcated.     

Phase formation in the V<Subscript>2</Subscript>O<Subscript>5</Subscript>-Nb<Subscript>2</Subscript>O<Subscript>5</Subscript>-MoO<Subscript>3</Subscript> system

The solid-phase interaction in the V₂O₅-Nb₂O₅-MoO₃ system has been investigated, and the formation of a solid solution bounded by the compositions MoNb₂V₄O_{18 ? δ}, Mo₂NbV₅O_{21 ? δ}, Mo₂Nb₃V₃O_{21 ? δ}, and Mo₄Nb₉V₉O_{57 ? δ} has been found (δ is nonstoichiometry). In the V₂O₅?Nb₂O₅ system, the formation of three compounds is verified, namely, VNbO₅ (tetragonal structure), VNb₉O₂₅, and V₂Nb₂₃O_62.5. The first two compounds are isostructural and form a continuous solid solution with tetragonal symmetry. A new compound of the composition Mo₃NbVO_{14 ? δ} has been synthesized. This compound is isostructural to the Mo₃Nb₂O₁₄ compound described in the literature and forms a tetragonal solid solution with it. The phase equilibria in the V₂O₅-Nb₂O₅-MoO₃ system in the subsolidus region have been determined.     

Thermal behaviour and properties of Na<Subscript>2</Subscript>O-TiO<Subscript>2</Subscript>-P<Subscript>2</Subscript>O<Subscript>5</Subscript> glasses

Differential scanning calorimetry (DSC) and thermomechanical analysis (TMA) were used to study the thermal behaviour of (50-x)Na₂O-xTiO₂-50P₂O₅ and 45Na₂O-yTiO₂-(55-y)P₂O₅ glasses. The addition of TiO₂ to the starting glasses (x=0 and y=5 mol% TiO₂) resulted in a nonlinear increase of glass transition temperature and dilatation softening temperature, whereas the thermal expansion coefficient decreased. All prepared glasses crystallize under heating within the temperature range of 300–610°C. The contribution of the surface crystallization mechanism over the internal one increases with increasing TiO₂ content. With increasing TiO₂ content the temperature of maximum nucleation rate is also gradually shifted from a value close to the glass transition temperature towards the crystallization temperature. X-ray diffraction measurements showed that the major compounds formed by glass crystallization were NaPO₃, TiP₂O₇ and NaTi₂(PO₄)₃. The chemical durability of the glasses without titanium oxide is very poor, but with the replacement of Na₂O or P₂O₅ by TiO₂, it increases sharply.     

Glasses in the CuNbOF<Subscript>5</Subscript>-BaF<Subscript>2</Subscript> and CuNbOF<Subscript>5</Subscript>-PbF<Subscript>2</Subscript> systems

Nonhygroscopic, colored glasses have been synthesized in the CuNbOF₅-BaF₂ and CuNbOF₅-PbF₂ systems proceeding from crystals of the complex compound CuNbOF₅ · 4H₂O. The glasses have been studied structurally and thermally. The crystallization resistance of the glasses has been studied as a function of glass composition. Lead difluoride glasses are more stable than barium difluoride glasses of the same composition. These glasses have lower glass-transition temperatures than the binary glasses formed in the NbO₂F-BaF₂ system. The glass structure is built of Nb(O,F)₆ polyhedra, which are linked in glass networks through oxygen bridges. Modifier cations influence both the structure of glass networks and the linkage of polyhedra.     

Oxonitrates VO(NO<Subscript>3</Subscript>)<Subscript>3</Subscript> and MoO<Subscript>2</Subscript>(NO<Subscript>3</Subscript>)<Subscript>2</Subscript> and nitronium and nitrosonium nitratometallates as nitrating agents

Dissolution of vanadium in anhydrous HNO₃ followed by exposure of the solution in a dessicator over P₂O₅ gave liquid vanadyl trinitrate (I). The X-ray diffraction analysis of I was carried out for a single crystal grown on cooling the liquid in a sealed capillary. The structure is composed of VO(NO)₃ molecules in which the V atom has an unusually high C.N. 7; it coordinates the terminal O atom and three bidentate nitrate groups to form a distorted pentagonal bipyramid as the coordination polyhedron with the terminal O atom occupying one axial vertex. Using the GAMESS program package, ab initio calculation of the structure of VO (NO₃)₃ in the liquid phase was carried out. It was shown that in all three physical states, vanadyl trinitrate retains its molecular structure almost invariable. Toluene and naphthalene nitration using I and (NO₂)[Fe(NO₃)₄], NO[Cu(NO₃)₃], (NO)_3/4(NO₂)_1/4[Zr(NO₃)₅], and MoO₂(NO₃)₂ proceeds at high rates at low temperatures to give an unusually high para-nitrotoluene percentage in the products as compared with the ortho-isomer. The activity of the studied compounds in the nitration of naphthalene decreases in the series VO(NO₃)₃ > (NO)_3/4(NO₂)_1/4[Zr(NO₃)₅] > MoO₂(NO₃)₂.     

Novel Visible-Light-Driven Photocatalyst Co<Subscript>3</Subscript>O<Subscript>4</Subscript>/FeWO<Subscript>4</Subscript> for Efficient Decomposition of Organic Pollutants

A highly efficient and visible light (λ ≥ 420 nm) responsive composite photocatalyst, Co₃O₄/FeWO₄ was prepared by simple impregnation method. The heterojunction semiconductors Co₃O₄/FeWO₄ demonstrated notably high photocatalytic activity over a wide range of composition than the individual component Co₃O₄ or FeWO₄ for the complete degradation of 1,4-dichlorobenzene (DCB) in aqueous phase under visible light irradiation. The photocatalytic activity of composite was optimized at 1/99 Co₃O₄/FeWO₄ composition. After 2 h of visible light irradiation 51% decomposition of 1,4-dichlorobenzene (DCB) was observed utilizing 1/99 Co₃O₄/FeWO₄ photocatalyst while the end members demonstrated a negligible degradation under the same experimental condition. The valence band (VB) and conduction band (CB) of Co₃O₄ is located above the VB and CB of FeWO₄, respectively. Both the semiconductors Co₃O₄ and FeWO₄ exhibit strong absorption over the wide range of visible light. The obviously enhanced photocatalytic performance of Co₃O₄/FeWO₄ composite has been discussed on the hole (h⁺) as well as electron (e^?) transfer mechanism between the VB and CB of individual semiconductors.     

Crystal structure of KPb<Subscript>2</Subscript>Cl<Subscript>5</Subscript> and KPb<Subscript>2</Subscript>Br<Subscript>5</Subscript>

The KPb₂Cl₅ and KPb₂Br₅ crystals are monoclinic (P2₁/c) with a microtwinned structure. X-ray analysis of chloride resulted in the parameters a = 8.854(2) Å, b = 7.927(2) Å, c = 12.485(3) Å; β = 90.05(3)°, d_calc = 4.78(1) g/cm³ (STOE STADI4, MoK_α, 2θ_max = 80°), R₁ = 0.0702 for 4094 F ≥ 4 σ(F) reflections. For bromide, a = 9.256(2) Å, b = 8.365(2) Å, c = 13.025(3) Å; β = 90.00(3)°, d_calc = 5.62(1) g/cm³ (Bruker P4, MoK_α, 2θ_max = 70°), R₁ = 0.0692 for 3076 F ≥ 4 (F) reflections.     

The synthesis and selected properties of Co<Subscript>2</Subscript>InV<Subscript>3</Subscript>O<Subscript>11</Subscript>

It has been demonstrated that Co₂V₂O₇ and InVO₄ react with each other forming a new compound of the Co₂InV₃O₁₁ formula, when their molar ratio is equal to 1:1, or among CoCO₃, In₂O₃ and V₂O₅, mixed at a molar ratio of 4:1:3. This compound melts incongruently at the temperature of 960±5°C, depositing crystals of InVO₄. It crystallizes in the triclinic system and the unit cell parameters amount to: a=0.6524(6) nm, b=0.6885(5) nm, c=1.0290(4) nm, α=96.5°, β=104.1°, γ=100.9°, Z=2. The phase equilibria being established in the Co₂V₂O₇–InVO₄ system over the whole components concentration range up to the solidus line were described.