Crystal Structures and Characterizations of Bis(pyrrolidinedithiocarbamato)Cu（Ⅱ） and Zn(Ⅱ） Complexes

The structures of [Cu (S₂CN (CH₂)₄)₂] (1) and [Zn₂(S₂CN‐(CH₂)₄)₄] (2) have been determined by X‐ray crystallography analysis. They are all isomorphous and triclinic, space group of P1^?, with Z = 1. The lattice parameters of compound 1 is: a = 0.63483(2) nm, b = 0.74972(3) nm, c=0.78390(1) mn, α = 75.912(2)°, β = 78.634(2)° and γ = 86.845(2)°; compound 2: a = 0.78707(6) nm, b=0.79823(6) nm, c = 1.23246(9) nm, α = 74.813(2)°, β = 73.048(2)° and γ = 88.036(2)°. The copper atom is located on a crystallographic inversion center and zinc atom lies across centers of symmetry. The Cu(II) ion has a square‐planar geometry while Zn(II) has a distorted tetrahedral geometry. The thermal gravity (TG) data indicate that no structural transitions in the two compounds were abserved and the decomposition products can adsorb gas. Also they all have a high thermal stability.     

Effect of the modifier ion on the properties of MgFe<Subscript>2</Subscript>O<Subscript>4</Subscript> and ZnFe<Subscript>2</Subscript>O<Subscript>4</Subscript> pigments

Magnesium and zinc ferrites have been prepared by the polymeric precursor method. The organic material decomposition was studied by thermogravimetry (TG) and differential thermal analysis (DTA). The variation of crystalline phases and particle morphology with calcination temperature were investigated using X-ray diffraction (XRD) and scanning electronic microscopy (SEM), respectively. The colors of the ferrites were evaluated using colorimetry. Magnesium ferrite crystallizes above 800°C, presenting a yellow- orange color with a reflectance peak at the 600–650 nm range, while zinc ferrite crystallizes at 600°C, with a reflectance peak between 650–700 nm, corresponding to the red-brick color.     

Conductimetric determination of ion-association constants for calcium,cobalt, zinc,and cadmium sulfates in aqueous solutions at various temperatures between 0°C and 45°C

Thermodynamic ion-association constants for calcium, cobalt, zinc, and cadmium sulfates in aqueous solutions were determined by means of conductivity measurements at various temperatures between 0°C and 45°C. The standard Gibbs energy, enthalpy, and entropy for the reaction M ²⁺ +SO ₄ ^2– M ²⁺ ·SO ₄ ^2– (M=Ca, Co, Zn, and Cd) were calculated from the temperature dependence of the ion-association constants. The values obtained are as follows: G ₂₉₈ ^o =–12.42 kJ-mole ^–1 , H ^o =6.11 kJ-mole ^–1 , and S ₂₉₈ ^o =62.1 J- ^o K ^–1 -mole ^–1 for Ca ²⁺ ·SO ₄ ^2– ; G ₂₉₈ ^o =–12.84 kJ-mole ^–1 , H ^o =5.00 kJ-mole ^–1 , and S ₂₉₈ ^o =59.8 J- ^o K ^–1 -mole^–1 for Co ²⁺ ·SO ₄ ^2– ; G ₂₉₈ ^o =–12.65 kJ-mole ^–1 , H ^o =8.65 kJ-mole ^–1 , and S ₂₉₈ ^o =71.4 J- ^o K ^–1 -mole ^–1 for Zn ²⁺ ·SO ₄ ^2– ; G ₂₉₈ ^o =–13.28 kJ-mole ^–1 , H ^o =8.39 kJ-mole ^–1 , and S ₂₉₈ ^o =72.7 J- ^o K ^–1 -mole ^–1 for Cd ²⁺ ·SO ₄ ^2– .     

The role of anhydrous zinc nitrate in the thermal decomposition of the zinc hydroxy nitrates Zn5(OH)8(NO3)2·2H2O and ZnOHNO3·H2O

The steps associated with the thermal decomposition of Zn₅(OH)₈(NO₃)₂·2H₂O and ZnOHNO₃·H₂O are re-examined. Previous reports have suggested that Zn₅(OH)₈(NO₃)₂·2H₂O decomposes to ZnO via two intermediates, Zn₅(OH)₈(NO₃)₂ and Zn₃(OH)₄(NO₃)₂ whereas ZnOHNO₃·H₂O has been reported to decompose to ZnO via a Zn₃(OH)₄(NO₃)₂ intermediate. In this study, we demonstrate using TG, mass spectral analysis of evolved gases and in situ variable temperature powder X-ray diffraction analysis that, in fact, in the decomposition of Zn₅(OH)₈(NO₃)₂·2H₂O an anhydrous zinc nitrate intermediate is also involved. We, additionally, show that the decomposition of ZnOHNO₃·H₂O to ZnO also involves the formation of an anhydrous zinc nitrate intermediate. The anhydrous zinc nitrate formed in both cases is poorly crystallised and this observation may explain why this phase could not be observed by PXRD analysis in the previous studies.     

Mineralization of 4-Chlorophenol under Visible Light Irradiation in the Presence of Aluminum and Zinc Phthalocyaninesulfonates

Photosensitized oxidation of 4-chlorophenol (4CP) by the title complexes (AIPcS and ZnPcS) in aerated aqueous solution uponvisible light irradiation(λ=450nm) has been investigated using methanol as a disassociating reagent.It is confirmed that the monomeric species of the sesitizer is more active than the corresponding dimer in singlet oxygen generation for 4CP oxidation.However,the monomer is also the main component found in the sensitlzer‘s photobleaching, In this reload, AIPcS is much more stable than ZnPcS, and the Dhotoble~hlno is observed to proceed via singlet and triplet oxygen, respectlvely.The final products of 4CP oxidation in alkaline solution are carbon dioxide and chloride ions.while at pH=7 and pH=3 the p-benzoquinone is the product.The temperature is found to have influence on both the photosensitized degradation of methyl orange and ZnPcS photobleaching,with an activation energy of 15.8 and 24.2kJ/mol,respectively.     

Convective instability of a zinc sulfate solution in a cell with horizontal plane-parallel electrodes

The Rayleigh-Bénard convective instability in a cell with horizontal zinc electrodes is considered. The space between the electrodes is filled with a ZnSO₄ solution. The linear plot of the difference between the zinc deposition currents (I) in the cases where the anode is the upper or lower electrode vs. the square root of the zinc deposition current in the absence of convection is found experimentally. It is shown that the critical Rayleigh number can be determined by an extrapolation of this plot.Translated from Elektrokhimiya, Vol. 41, No. 2, 2005, pp. 247–249.Original Russian Text Copyright © 2005 by Tomashova, Teplitskaya, Grigin, Davydov.     

Photoinduced hydrogen evolution with water soluble bisviologen linked zinc porphyrin and hydrogenase

Water soluble bisviologen linked zinc porphyrin (ZnP(C₄V_AC₄V_B)₄) was synthesized and characterized. The quenching processes of the photoexcited singlet state and triplet state of ZnP(C₄V_AC₄V_B)₄ were measured by using fluorescence lifetime and laser flash photolysis. The photoexcited singlet state of the zinc porphyrin was quenched by the bonded bisviologen. Photoinduced hydrogen evolution with ZnP(C₄V_AC₄V_B)₄ and hydrogenase was observed under steady state irradiation.     

2,6—二乙酰吡啶类双希夫碱配合物的研究——Ⅲ.Co(Ⅱ)、Ni(Ⅱ)、Zn(Ⅱ)、Pb(Ⅱ)和Cd(Ⅱ)配合物的合成和表征

制备了由2,6—二乙酰吡啶和肼基硫代甲酸酯衍生的希夫碱C_5H_3N[CH=NNHC(S)XR]_2(X=S,R=CH_3、C_6H_5CH_2;X=O,R=C_6H_5CH_2).离析出类型为MC_5H_3N[CH=NN=C(S)XR]_2(M=Co~(2+)、Ni~(2+)、Zn~(2+)、Pb~(2+)和Cd~(2+))的希夫碱配合物.配合物为元素分析、红外、可见—紫外光谱以及磁化率测量所表征.结果指出:上述希夫碱均为N_3S_2型五齿配体.     

The rich crystal chemistry of the AMM′(PO4)2 morphotropic series: NaZnAl(PO4)2, the first Na representative with a new structure type

A novel phosphate, sodium zinc aluminium bis(phosphate), NaZnAl(PO₄)₂, was obtained under mild‐temperature hydrothermal conditions at 553 K. The crystal structure has been studied using single‐crystal X‐ray experimental data. The pseudo‐hexagonal phase NaZnAl(PO₄)₂ crystallizes in the monoclinic space group P2₁/c. Its unique crystal structure is based on a three‐dimensional (3D) framework built by Zn‐, Al‐ and P‐centred tetrahedra sharing vertices. Channels parallel to the [101] and [01] directions are limited by six‐ and eight‐membered windows, and incorporate Na atoms. The new compound is discussed as a member of the morphotropic series AMM′PO₄, where A = Na, K, Rb or NH₄, M = Cu, Ni, Co, Fe, Zn or Mg and M′ = Fe, Al or Ga. The title compound is the first Na representative within the series and is characterized by a 3D architecture of tetrahedra populated in an ordered manner by Zn²⁺, Al³⁺ and P⁵⁺ ions.     

有机-无机复合物[H2(PW12O40){Zn(C10H8N2)2(H2O)}]·1.5[Zn(C10H8N2)3]·1.75H2O的合成、结构及性能

An organic-inorganic hybrid complex, [H₂(PW₁₂O₄₀){Zn(C₁₀H₈N₂)₂(H₂O)}]·1.5[Zn(C₁₀H₈N₂)₃]·1.75H₂O has been synthesized hydrothermally and structurally characterized by X-ray crystallography. The crystal belongs to monoclinic, space grounp C2/c, with a=4.709 4(2) nm, b=1.431 77(7) nm, c=2.621 07(1) nm, β=90.125(4)°, V=17.673 4(2) nm³, Z=8, D_c=3.087 Mg·m^-3, F(000)=14 884, μ(Mo Kα)=16.327 mm^-1. The structure was refined to R₁=0.068 7 and wR₂=0.158 0 for 20 128 observed reflections with I>2σ(I). Single crystal structure shows that the title compound is constructed from [PW₁₂O₄₀]^3- cluster anion and [Zn(C₁₀H₈N₂)₂(H₂O)]²⁺ metal-organic complex cation, in which metal Zn(Ⅱ) cation are coordinately bonded to the terminal oxygen of Keggin polyanions. The title compound exhibits good catalytic activity for oxidation of benzaldehyde to benzoic acid. CCDC: 624772.