Effects of CuCl2��6H2O and ZnCl2��6H2O on the viscosity of aqueous ethanol mixtures

The effects of CuCl₂ and ZnCl₂ on the viscosity in aqueous ethanol mixtures (10%–50% v/v) were studied in the concentration range 1.0×10⁻²–8.0×10⁻² mol·dm⁻³ at different temperatures. It was found that the viscosities increased with an increase in the concentration of the salts and percent composition of ethanol content, whereas it decreased with an increase in temperature. Ion-ion and ion-solvent interactions are determined with the help of A- and B-coefficients of Jones-Dole equation. The values of A- and B-coefficients are irregular and increase with a rise in temperature and also with an increase in ethanol contents for both salts. Negative values of B-coefficients show that ion solvent interactions is comparatively small and suggest that CuCl₂ and ZnCl₂ behave as structure breakers in aqueous ethanol mixtures. Thermodynamic parameters like the energy of activation (E _η ) and change in entropy of activation (ΔS*) were also evaluated which confirm the structure breaker behavior of salts in aqueous ethanol mixtures.     

An analysis of the vibrational frequencies and amplitudes of the H5O+2 ion in H4SiW12O40·6H2O (TSA·6H2O) and H3PW12O40·6H2O (TPA·6H2O)

The infrared, Raman and inelastic neutron scattering (INS) spectra of TSA·6H₂O and TPA·6H₂O are in agreement with those expected for the presence of H₅O⁺₂ ions. Force fields for different assignment schemes are compared with the observed vibrational frequencies and the INS spectral profile. All but two schemes are eliminated. Whilst low-resolution INS spectroscopy cannot distinguish between these two schemes, the orientations of the vibrational ellipsoids for one scheme are in better agreement with those reported from low-temperature crystallographic studies of the H₅O⁺₂ ion.     

Tetranuclear bismuth complexes Bi4(O)2(O2CC6H2F3-3,4,5)8 · 2C6H6 and Bi4(O)2(O2CC6H2F3-3,4,5)8 · 2C6H4Me2-1,4: Synthesis and structures

X-ray diffraction study of tetranuclear organobismuth complexes Bi₄(O)₂(O₂CC₆H₂F₃-3,4,5)₈ · 2⁶-C₆H₆ and Bi₄(O)₂(O₂CC₆H₂F₃-3,4,5)₈ · 2(C₆H₄Me₂-1,4) revealed four Bi atoms connected through the bridging carboxylate ligands and the O atoms. The coordination sphere of the terminal Bi atoms includes the chelate carboxylate ligand and the 6-arene molecule. The bridging O atoms are tricoordinated, the distances between the terminal Bi atom and the center of benzene molecule (1,4-dimethylbenzene) are 3.024 Å(3.131 Å).Translated from Koordinatsionnaya Khimiya, Vol. 31, No. 1, 2005, pp. 4–11.Original Russian Text Copyright © 2005 by Sharutin, Egorova, Sharutina, Ivanenko, Adonin, Starichenko, Pushilin, Gerasimenko.     

Hydrothermal Synthesis and Crystal Structure of a New Phosphonate： {[Cu（1,10-phen）]2-（H2O3PCH2C6H4C6H4CH2PO3H）2-（HO3PCH2C6H4C6H4CH2PO3H） }n

1 INTRODUCTION Metal organophosphonates have attracted considerable attention for over three decades due to their potential or practical applications, include- ing ion exchanges[1, 2], molecular sensors[3] and optics[4, 5]. Recently, a number of porous m…     

Synthesis and Crystal Structure of a Dialkyltin Benzamidoacetate Compound {[n-Bu2Sn（O2CCH2NHCOC6H5）]2O}2·C6H6

A dialkyltin benzamidoacetate compound {[n-Bu2Sn（O2CCH2NHCOC6H5）]2O}2· C6H6 has been synthesized by the reaction of dialkyltin oxide with benzamidoacetic acid in 1：1 molar ratio, and its structure was determined by X-ray single-crystal diffraction. The crystal belongs to orthorhombic, space group Pca21, with a = 1.9134（4）, b = 1.9605（4）, c = 2.0657（4） nm, Z = 4, V = 7.749（3） nm^3, Dc = 1.054 mg·m^-3,μ（MoKa） = 1.337 mm^-1, F（000） = 3576, the final R = 0.0405 and wR = 0.0860. According to the structural analysis, the tin atom adopts a distorted five-coordinate trigonal bipyramidal geometry, and the dimer structure is shaped by one planar four-membered Sn2O2 ring.     

Syntheses and structures of p-HOOCC6F4COOH · H2O (H2L · H2O) and luminescent coordination polymers [Tb2(H2O)4(L)3 · 2H2O] n and Tb2(Phen)2(L)3 · 2H2O

Compounds p-HOOCC₆F₄COOH · H₂O (H₂L · H₂O), [Tb₂(H₂O)₄(L)₃ · 2H₂O] _n (I), and Tb₂(Phen)₂(L)₃ · 2H₂O (II) are synthesized. According to the X-ray structure analysis data, the crystal structure of H₂L · H₂O is built of centrosymmetric molecules H₂L and molecules of water of crystallization. The crystal structure of compound I is built of layers of coordination 2D polymer [Tb₂(H₂O)₄(L)₃] _n and molecules of water of crystallization. The ligands are the L^2? anions performing both the tetradentate bridging and pentadentate bridging-chelating functions. The coordination polyhedron TbO₉ is a distorted three-capped trigonal prism. Acid H₂L manifests photoluminescence in the UV region (??_max = 368 nm). Compounds I and II have the green luminescence characteristic of the Tb³⁺ ions, and the band with ??_max = 545 nm (transition ⁵ D ₄?? ⁷ F ₅) is maximum in intensity. The photoluminescence intensity of compound II is higher than that for compound I.     

Quantum instanton calculation of rate constants for the C2H6 + H → C2H5 + H2 reaction: anharmonicity and kinetic isotope effects

Thermal rate constants and kinetic isotope effects for the title reaction are calculated by using the quantum instanton approximation within the full dimensional Cartesian coordinates. The obtained results are in good agreement with experimental measurements at high temperatures. The detailed investigation reveals that the anharmonicity of the hindered internal rotation motion does not influence the rate too much compared to its harmonic oscillator approximation. However, the motion of the nonreactive methyl group in C(2)H(6) significantly enhances the rates compared to its rigid case, which makes conventional reduced-dimensionality calculations a challenge. In addition, the temperature dependence of kinetic isotope effects is also revealed.     

Synthesis and Characterization of Diorganotin Compounds {[R2Sn（ON =CHC6H5）]2O}2 and Crystal Structure of {[（C6H5CH2）2Sn（ON=CHC6H5）]2O}2

Introduction Dimeric tetraorganodistannoxanes are a kind of in-teresting organotin oxo clusters and have attracted con-siderable attention during the last several decades, in view of their unique structural features1-5 as well as their applications as biocides6,7 and in homogenous cataly-sis.8,9 In the solid state, they contain characteristic Sn4O2X2Y2 structural motifts with staircase or ladder arrangements, a planar four-membered Sn2O2 ring and, generally, penta-coordination around the tin…     

B2H6分子中的化学键

在结构化学的教学中,常常要讨论二硼烷(B2H6)等“缺电子分子”的几何结构和化学键的性质.二硼烷的几何结构已早有定论,因为无论是它的化学性质,还是包括电子衍射、核磁共振、X-射线在内的广泛物理化学研究,都表明两个硼原子与四个端氢原子共平面,另外两个氢原子在平面的上下(如图所示).而且,该分子结构中存在三中心双电子化学键也为大家普遍接受.然而,关于B2H6分子中三中心化学键的解释在教科书中却各持己见,甚至同一本书中有两种不同的观点[1].     

Syntheses, Spectroscopic Properties and Crystal Structures of （2-Cl-C6H4CH2）3SnS2CN（C5H10） and （2-Cl-C6H4CH2）3SnS2CN（C4H9N）

1 INTRODUCTION The chemistry of organotin(IV) complexes was extensively studied due to their biological activity and coordination chemistry[1～7]. More recently, phar- maceutical properties of alkyltin(IV) complexes with dithiocarbamate ligands have bee…     

Synthesis and physicochemical study of diazabicycloundecene hexamolybdochromate [C9H16N2]H3[CrMo6O18(OH)6] · 2H2O

Quinazoline hexamolybdochromate [C₉H₁₆N₂]H₃[CrMo₆O₁₈(OH)₆] · 2H₂O has been synthesized and studied by mass spectroscopy, X-ray powder diffraction, thermogravimetry, and IR and NMR spectroscopy. The compound crystallizes in triclinic system with the unit cell parameters a = 15.06 Å, b = 13.08 Å, c = 8.17 Å, α = 59.85°, β = 123.15°, γ = 107.01°, V = 1165.62 ų, ρ_pycn = 3.58 g/cm³, and Z = 2.     

Fourier-transform Raman and infrared spectra and normal coordinate analysis of (C6H5)2BiCl and [N(CH3)4]+[(C6H5)2BiCl2]−

The vibrational properties of the diphenylbismuth(III) chloride compounds (C₆H₅)₂BiCl and [N(CH₃)₄]⁺[(C₆H₅)₂BiCl₂]⁻ have been investigated. A comprehensive assignment of the fundamental modes in the measured Fourier-transform Raman and infrared spectra has been carried out. Normal coordinate calculations of these compounds based on new X-ray crystal structure data have been performed to identify the BiCl stretching and bending vibrations of both compounds. For [N(CH₃)₄]⁺[(C₆H₅)₂BiCl₂]⁻ in the solid state, the ν_s(BiCl₂) and ν_as(BiCl₂) occur at 215 cm⁻ (Raman) and 237 cm⁻ (Raman), respectively, in good agreement with the calculated wavenumbers. The force constant calculation yields a BiCl stretching force constant of 0.89 × 10² N m⁻¹.     

Synthesis, crystal structures, and properties of [Ca(H2O)2(Dmf@CB[6])(Bdc)] · DMF · 4H2O and [Ca(H2O)3(Dmf@CB[6])]Cl2 · 2H2O

Complexes [Ca(H₂O)₂(Dmf@CB[6])(Bdc)] · DMF · 4H₂O (I) and [Ca(H₂O)₃(Dmf@CB[6])]Cl₂ · 2H₂O (II) are synthesized by the heating (95°C) of a mixture of calcium chloride and cucurbit[6]uril (CB[6]) in a mixture of dimethylformamide (DMF) and water with the addition of terephthalic acid (H₂Bdc) in the case of complex I or triethylamine for complex II. The compounds are characterized by X-ray diffraction analysis, IR spectroscopy, and thermogravimetric and elemental analyses. The luminescence spectra are also recorded. According to the X-ray diffraction data, the calcium atom is coordinated by the oxygen atoms of the cucurbit[6]uril molecule, water molecules, and terephthalate anion (for I). The internal cavity of the cavitand is occupied by DMF.     

Syntheses and Crystal Structures of (H3O)(C3H5N2)[Mn(OH)6 Mo6O18]·3.5H2O and (H3O)3[Co(OH)6Mo6O18]·7H2O

The crystals of the title compounds (H3O)(C3H5N2)[Mn(OH)6Mo6O18]·3.5H2O 1 and (H3O)3[Co(OH)6Mo6O18]·7H2O 2 have been prepared and structurally determined by X-ray single-crystal diffraction. Compound 1 crystallizes in monoclinic, space group C2/c with a = 21.5018(9), b = 10.9331(5), c = 11.8667(5)A,β = 95.3570(10)o, V = 2777.5(2)A3, Z = 4, Dc = 2.802 g/cm3, Mr = 1171.80,μ(MoKα) = 3.173 mm-1, F(000) = 223, the final R = 0.0458 and wR = 0.1041 for 2093 observed reflections (I>2σ(I)); Compound 2 crystallizes in monoclinic, space group P21/c with a = 11.4042(12), b = 10.9481(11), c = 11.6722(12)A, β= 99.948(2)o, V = 1435.4(3)A3, Z = 2, Dc = 2.794 g/cm3, Mr = 1207.80,μ(MoKα) = 3.223 mm-1, F(000) = 1160, the final R = 0.0544 and wR = 0.1066 for 1906 observed reflections (I > 2σ(I)). Both compounds 1 and 2 adopt the Anderson structure, in which the anion is of centrosymmetry and formed by six octahedral edge-sharing MoO6 units surrounding the central MO6 (M = Mn or Co) octahedron.     

Three organic–inorganic hybrid B-Anderson polyoxoanions as building blocks: syntheses,structures, and characterization of [(C6H5NO2)2Ln(H2O)6](CrMo6O24H6)·2C6H5NO2·6H2O (Ln = Sm,Dy, Er)

Three new B-Anderson type polyoxometalates, [(C₆H₅NO₂)₂Ln(H₂O)₆](CrMo₆O₂₄H₆)·2C₆H₅NO₂·6H₂O (Ln?=?Sm 1, Dy 2 and Er 3), have been synthesized in aqueous solution and structurally characterized by single-crystal X-ray diffraction, IR spectra, UV spectroscopy, and fluorescence spectroscopy. Crystal structure analysis reveals that these three compounds have the same composition and are isostructural, assembled by B-Anderson type polyoxoanion [CrMo₆O₂₄H₆]^3?, rare-earth ions, and ligands. UV spectroscopy shows that 1 is stable when pH is 4.50–5.83. The fluorescence spectra of 2 indicate that both rare-earth ions Dy³⁺ and pyridine-4-carboxylic acid ligands function in the charge transition of the compound.     

Synthesis and Crystal Structure of [Ni(H2O)6][Ni(H2O)2(C4H2O4)]·4H2O

Reaction of a freshly prepared Ni(OH)_{2?2 x} (CO₃) _x ·yH₂O with maleic acid in H₂O at room temperature afforded [Ni(H₂O)₆][Ni(H₂O)₂(C₄H₂O₄)]·4H₂O, which consists of [Ni(H₂O)₆]²⁺ cations, [Ni(H₂O)₂(C₄H₂O₄)]^2? anions and lattice H₂O molecules. Ni atoms in cations are octahedrally coordinated and Ni atoms in anions are each octahedrally coordinated by bidentate chelating maleato ligands and two water molecules at trans positions. Cations and anions are interlinked by hydrogen bonds to form 1D chains, which are hexagonally arranged and connected by the lattice water molecules. When heated in a flowing argon stream, the compound decomposes, with complete dehydration being followed by dissociation of nickel maleate into NiO and maleic anhydride.     

Crystal and molecular structure of the [Nd2(H2O)8(C6F5COO)6]·2H2O Compound

A compound with the composition Nd(C₆F₅COO)₃· H₂O (I) is prepared. Single crystals are grown, and their single crystal XRD analysis of the Nd₂(H₂O)₈(C₆F₅COO)₆]·2H₂O (II) compound is performed. The crystals are triclinic: a = 7.693(2) Å, b = 9.394(2) Å, c = 18.203(4) Å, α = 81.91(3)°, β = 84.41(3)°, γ = 88.97(3)°, Z = 1, d _x = 2.223 g/cm³. The structure is composed of symmetrical molecules of the binuclear [Nd₂(H₂O)₈(C₆F₅COO)₆] complex and crystallization water molecules. The C₆F₅COO^- ligands are monodentate and tridentate bridging- chelating, which results in a closure of two four-membered chelate cycles NdO₂C and a four-membered metal cycle Nd₂O₂. The NdO₉ polyhedron is a distorted one-capped tetragonal antiprism.     

The Synthesis and Characterization of [4-CH3OC6H4CH2NH3]4P2O7·6H2O

Inorganic–organic hybrid compounds exhibit interesting properties in several application areas. In this regard, chemical preparation and characterization by X-ray diffraction, thermal analysis, and IR spectroscopy are given for a new organic cation diphosphate [4-CH₃OC₆H₄CH₂NH₃]₄P₂O₇·6H₂O. This later crystallizes in a C2/c unit cell with a = 38.238(6)Å, b = 6.453(1)Å, c = 16.942(7)Å; β = 97.60(4)°; Z = 4; and V = 4144(2)ų and D_x = 1.377 g·cm^?3. Its crystal structure has been determinated and refined to R = 0.044, using 7978 independent reflections. This atomic arrangement consists of inorganic layers built up from P₂O₇ ^4? anions and water molecules. On these layers, which are parallel to the (b, c) planes, the (4-CH₃OC₆H₄CH₂NH₃)⁺ cations are anchored through multiple hydrogen bonds.