共查询到20条相似文献,搜索用时 31 毫秒
1.
O. A. Novruzova O. P. Rakhmanova A. E. Galashev 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2007,81(11):1825-1828
The stability and structure of water clusters absorbing nitrogen molecules or argon atoms was analyzed by molecular dynamics simulation at 233 K. The (?μ/?i)V, T derivative of the chemical potential, a value characterizing the stability of a cluster with respect to its size, depends linearly on the number of molecules i. According to this criterion, the clusters under study become stable near i = 40. The average length of H-bonds increases monotonically in the growing cluster of pure water and exhibits oscillatory behavior if the growing cluster contains N2 molecules or Ar atoms. The number of H-bonds per molecule oscillates between one and six as the cluster size changes. These oscillations are damped in pure water and sustained for clusters containing impurities, especially argon. 相似文献
2.
Yu. V. Kokunov Yu. E. Gorbunova V. V. Kovalev 《Russian Journal of Coordination Chemistry》2009,35(9):643-647
The complex [Co(2-Me-Pyz)2(H2O)4](NO3)2 is synthesized and its structure is determined. The crystals are monoclinic: space group P21/n, a = 10.685(2) Å, b = 6.837(1), c = 12.515(3) Å, β = 91.84(3)°, V = 913.8(3) Å3, ρcalcd = 1.042 g/cm 3, Z = 2. The Co2+ ion (in the inversion center) is coordinated at the vertices of the distorted octahedron by two nitrogen atoms of methylpyrazine and four oxygen atoms of the water molecules (Co(1)–N(1) 2.180(3), average Co(1)–O(w) 2.079(3) Å, angles at the Co atom 87.9(1)–92.1(1)°). Supramolecular pseudometallocycles are formed in the structure through the O(w)–H…N(1) hydrogen bonds between the coordinated H2O molecules and the terminal nitrogen atoms of the 2-methylpyrazine molecules. Their interaction results in the formation of supramolecular layers joined by the NO3 groups into a three-dimensional framework. 相似文献
3.
G. -H. Cui J. -C. Geng T. -F. Liu X. Peng C. -H. He C. -H. Jiao 《Journal of Structural Chemistry》2012,53(3):509-513
A novel copper(II) complex {[Cu(BIX)2(H2O)2](PhCOO)2} n (1) (BIX = 1,4-bis(imidazole-1-methyl))-benzene) is synthesized and characterized by elemental analysis, IR, TG, and single crystal X-ray diffraction. Complex 1 crystallizes in the triclinic crystal system with the P-1 space group, Z = 1, a = 9.465(2) Å, b = 9.703(2) Å, c = 12.060(2) Å, α = 77.26(3)°, β = 70.37(3)°, γ = 67.14(3)°, and V = 956.1(3) Å3. The crystal structural analysis of complex 1 shows that the copper center is six-coordinated in an elongated octahedral geometry by four N atoms from four different BIX and two O atoms from two water molecules; two neighboring Cu(II) cations are bridged by two BIX extending into an infinite 1D double chain structure. 相似文献
4.
H. Y. He 《Research on Chemical Intermediates》2011,37(8):1057-1067
Hydrogen gas as a clear energy resource was found to be largely bubbled from a H2O/H2O2/MnWO4 system. MnWO4 powder was fabricated by an aqueous reaction method. The powder was characterized with X-ray diffraction (XRD), transmission
electron microscope (TEM), and X-ray photoelectron spectrometry (XPS). The efficiency of the hydrogen generation increases
with an increase in initial pH in the appropriate range, H2O2 proportion, MnWO4 proportion, and intensity of light resource. Calcining at 400 °C for 1 h can make the MnWO4 powder synthesized by an aqueous reaction more effective for H2 generation and more stable in higher initial pH. The MnWO4 catalyst shows a long-term stability for photocatalytic H2 generation. A mechanism was suggested for the hydrogen generation from the H2O/H2O2/MnWO4 system together with XPS analysis. 相似文献
5.
E. J. Gao Y. Zhang Z. Wen L. Lin L. Dai T. D. Sun M. C. Zhu Y. Wang 《Russian Journal of Coordination Chemistry》2011,37(12):887-892
A novel complex [Cd(Bipy)2(L)] · 10H2O (I) (H2L = 2,6-pyridinedicarboxylic acid), has been synthesized by the reaction of bipyridyl and H2L with cadmium(II) salt. Elemental analysis, IR spectra, and X-ray single-crystal diffraction were carried out to determine the composition and crystal structure of complex I. The cadmium atom is seven-coordinated in a distorted pentagonal bipyramidal configuration. Ten water molecules formed a large water cluster with the oxygen atoms of the H2L ligand. The complexes form a 2D supramolecular framework and a 3D reticulate structure by hydrogen bonding and π-π-stacking of the neighboring bipyridyl ligands coming from the neighboring complexes. 相似文献
6.
L. B. Serezhkina E. V. Peresypkina A. V. Virovets E. V. Grechishnikova A. V. Savchenkov 《Russian Journal of Inorganic Chemistry》2011,56(11):1739-1746
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). 相似文献
7.
M. N. Sokolova N. A. Budantseva A. M. Fedoseev 《Russian Journal of Coordination Chemistry》2011,37(6):478-482
The U(VI) complex with cyanoacetic acid, [UO2(H2O)2(NCCH2COO)2] (I), was synthesized from an aqueous solution, and its X-ray diffraction analysis was carried out. The crystals are orthorhombic: space group Pca2 1, a = 25.9605(7) Å, b = 6.7634(2) Å, c = 6.3398(2) Å, V = 1113.15(6) Å3 at 100 K, and Z = 4. The coordination polyhedron of the uranium atom is a distorted pentagonal bipyramid. The cations UO 2 2+ are bound into infinite zigzag chains by the bridging carboxyl groups of one of the anions of cyanoacetic acid. The carboxyl oxygen atom of the second anion, which is not involved in coordination, and the nitrogen atoms of the cyano groups form hydrogen bonds with the coordination water molecules. The layer structure of the compound is formed through the hydrogen bonds. The absorption spectra in the visible and infrared ranges of the crystalline compound are measured and analyzed. 相似文献
8.
A new 3 D europium sulfate Eu2(H2O)4(SO4)3 1 is synthesized solvothermally and characterized by single crystal X-ray diffraction, IR spectrum, TG, powder XRD, and ultraviolet excitation and emission spectrum. This compound crystallizes in the triclinic system with the space group P-1, a = 6.7520(9) Å, b = 9.1077(12) Å, c = 10.5910(14) Å, α = 94.432(2)°, β = 107.1170(10)°, γ = 99.160(2)°, V = 609.17(14) Å3, Z = 2. The open framework of the title compound is an eight-membered ring channel along the crystallographic a-axis, which is built up by EuO8 polyhedra and SO4 tetrahedra. 相似文献
9.
The molar enthalpies of solution of 2-aminopyridine at various molalities were measured at T=298.15 K in double-distilled water by means of an isoperibol solution-reaction calorimeter. According to Pitzer’s theory,
the molar enthalpy of solution of the title compound at infinite dilution was calculated to be DsolHm¥ = 14.34 kJ·mol-1\Delta_{\mathrm{sol}}H_{\mathrm{m}}^{\infty} = 14.34~\mbox{kJ}\cdot\mbox{mol}^{-1}, and Pitzer’s ion interaction parameters bMX(0)L, bMX(1)L\beta_{\mathrm{MX}}^{(0)L}, \beta_{\mathrm{MX}}^{(1)L}, and CMXfLC_{\mathrm{MX}}^{\phi L} were obtained. Values of the relative apparent molar enthalpies (
φ
L) and relative partial molar enthalpies of the compound ([`(L)]2)\bar{L}_{2}) were derived from the experimental enthalpies of solution of the compound. The standard molar enthalpy of formation of the
cation C5H7N2 +\mathrm{C}_{5}\mathrm{H}_{7}\mathrm{N}_{2}^{ +} in aqueous solution was calculated to be DfHmo(C5H7N2+,aq)=-(2.096±0.801) kJ·mol-1\Delta_{\mathrm{f}}H_{\mathrm{m}}^{\mathrm{o}}(\mathrm{C}_{5}\mathrm{H}_{7}\mathrm{N}_{2}^{+},\mbox{aq})=-(2.096\pm 0.801)~\mbox{kJ}\cdot\mbox{mol}^{-1}. 相似文献
10.
Riadh Kefi Erwann Jeanneau Frederic Lefebvre Cherif Ben Nasr 《Structural chemistry》2007,18(6):923-929
Chemical preparation, crystal structure, and NMR spectroscopy of a new trans-2,5-dimethylpiperazinium monophosphate are given. This new compound crystallizes in the triclinic system, with the space group P-1 and the following parameters: a = 6.5033(3), b = 7.6942(4), c = 8.1473(5) Å, α = 114.997(3), β = 92.341(3), γ = 113.136(3), V = 329.14(3) Å3, Z = 1, and Dx = 1.565 g cm?3. The crystal structure has been determined and refined to R = 0.030 and R w(F 2) = 0.032 using 1558 independent reflections. The structure can be described as infinite [H2PO4] n n? chains with (C6H16N2)2+ organic cations anchored between adjacent polyanions to form columns of anions and cations running along the b axis. This compound has also been investigated by IR, thermal, and solid-state, 13C and 31P MAS NMR spectroscopies and Ab initio calculations. 相似文献
11.
Trino Suárez Bernardo Fontal Joel E. Vielma Marisela Reyes Fernando Bellandi Pedro Cancines Juan C. Díaz Yuraima Fonseca 《Transition Metal Chemistry》2011,36(6):617-620
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. 相似文献
12.
I. A. Bardina O. S. Zhukova N. V. Kovaleva S. N. Lanin 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2007,81(9):1525-1531
The adsorption of H2O and D2O on porous polymers, Chromosorb-102 (styrene-divinylbenzene copolymer) and MN-200 (supercross-linked polystyrene), was studied by gas chromatography. Test adsorbates used to study the properties of the surface of these polymers were n-alkanes (C6-C9), C6H6, and the polar compounds CHCl3, CH3NO2, CH3CN, (CH3)2CO, C2H5COOCH3, and (C2H5)2O. The experimental data on the retention of the sorbates were used to determine the contributions of dispersion and specific intermolecular interactions to the total energy of adsorption for the systems studied. The electron donor K D and electron acceptor K A characteristics of the surfaces of Chromosorb-102 and MN-200 were determined. The K D and K A values obtained allow these polymers to be classified as weakly specific adsorbents with the predominance of electron acceptor properties. The adsorption isotherms of H2O and D2O were measured at 55, 67, and 80°C. The dependences of the isosteric heats of adsorption Q st on adsorption values were determined. The conclusion was drawn that H2O interacted with the surface of the polymers by the adsorption mechanism, whereas absorption likely made a noticeable contribution to the retention of D2O. 相似文献
13.
S. N. Lanin E. B. Pashkova N. V. Kovaleva K. S. Lanina 《Russian Chemical Bulletin》2009,58(4):729-732
Adsorption of light and heavy water (H2O and D2O) on porous hypercross-linked polystyrene MN-272 was studied by gas chromatography. For the estimation of the properties
of this polymer surface, n-alkanes (C6—C9), C6
6, and polar compounds (CHCl3, MeNO2, MeCN, Me2CO, EtCOOCH3, Et2O) were used as test adsorbates. The contributions of energies of dispersion and specific (donor-acceptor) intermolecular
interactions to the total energy of adsorption were determined on the basis of experimental data on the retention of the sorbates.
The electron-donor and electron-acceptor characteristics of the hypercross-linked polystyrene MN-272 surface were estimated.
Hypercross-linked polystyrene MN-272 was found to be a weakly specific adsorbent with predomination of electron-donating properties.
The adsorption isotherms of H2O and D2O were measured on this polymer at 50, 60, and 70 °C. The dependences of the isosteric heats of adsorption on the amount adsorbed
were determined. The contribution of the energy of specific interactions to the total energy of adsorption for all polar adsorbates
(except for acetone, light and heavy water) does not exceed 20%. Adsorption of H2O on hypercross -linked polystyrene MN-272 is slightly weaker than that of D 2O. 相似文献
14.
Konstantin S. Gavrichev Mikhail A. Ryumin Alexander V. Tyurin Andrey V. Khoroshilov Larisa P. Mezentseva Alexander V. Osipov Valeriy L. Ugolkov Viktor V. Gusarov 《Journal of Thermal Analysis and Calorimetry》2010,102(2):809-811
Thermal behavior of LaPO4·nH2O and NdPO4·nH2O nanopowders from room temperature to 973 K was investigated by DSC, TA/DTG, ESM, and X-ray study. Mass loss due to the release
of adsorbed and hydrate water was found in the range from 323 to 623 K. Phase transitions from hexagonal structure nanopowders
to monoclinic one for bulk specimens were found above 873 K. 相似文献
15.
The ethylenediaminetetraacetate complex Li(H2O)3[Ga(Edta)] was synthesized and its crystal structure composed of octahedral (Ga(Edta)− anions connected to the Li(H2O)3+ ion through the oxygen atom was studied. Five of the six hydrogen atoms of water molecules are involved in weak hydrogen
bonds with the oxygen atoms of four Ga(Edta)− complexes, the complex anion is hydrogen-bonded to five water molecules. In addition, shortened contacts C(221)–H(22A)…O(112) between the Ga(Edta)− anions were found. As a result, the molecular packing in the crystal is determined by the three-dimensional lace of hydrogen
bonds. The results are compared with published data for the lithium salts of Bi(III), Sb(III), Fe(III), Ni(II), and Hg(II)
ethylenediaminetetraacetates. 相似文献
16.
Pedro Lima Forster Ademar Benevolo Lugao Hermi Felinto Brito Duclerc Fernandes Parra 《Journal of Thermal Analysis and Calorimetry》2009,97(2):497-502
Polymers doped with rare earth complexes are advantaged in film production for many applications in the luminescent field.
In this luminescent polycarbonate (PC) films doped with diaquatris(thenoyltrifluoroacetonate)europium(III) complex [Eu(TTA)3(H2O)2] were prepared and their calorimetric and luminescent properties in the solid state are reported. The thermal behavior was
investigated by utilization of differential scanning calorimetry (DSC) and thermogravimetry (TG). Due of the addition of rare
earth [Eu(TTA)3(H2O)2] into PC matrix, changes were observed in the thermal behavior concerning the glass transition and thermal stability. Characteristic
broadened narrow bands arising from the 5D0 → 7FJ transitions (J = 4−0) of Eu3+ ion indicate the incorporation of the Eu3+ ions in the polymer. The luminescent films show enhancement emission intensity with an increase of rare earth concentration
in polymeric matrix accompanied by decrease in thermal stability. 相似文献
17.
G. B. Andreev M. Yu. Antipin N. A. Budantseva E. V. Tuchina L. B. Serezhkina A. M. Fedoseev A. B. Yusov 《Russian Journal of Coordination Chemistry》2004,30(12):868-873
A complex of uranyl perchlorate with imidazolidine-2-one as the molecular ligand, [UO2(Imon)4(H2O)](ClO4)2 (I), was synthesized and structurally characterized by X-ray diffraction analysis. The coordination number of the uranium atom is 7. The nearest environment of the uranyl ion includes four O atoms of the imidazolidine-2-one molecules and one O atom of the water molecule. The perchlorate anions are outer-sphere ligands. The crystals are monoclinic: space group P21/c; a = 16.294(3) Å, b = 16.135(3) Å, c = 9.987(2) Å, = 97.69 (3)°, V = 2603.0 (9) Å3, (calcd) = 2.117 g/cm3, Z = 4. The IR and luminescence spectra of the complex were recorded.Translated from Koordinatsionnaya Khimiya, Vol. 30, No. 12, 2004, pp. 919–924.Original Russian Text Copyright © 2004 by Andreev, Antipin, Budantseva, Tuchina, Serezhkina, Fedoseev, Yusov. 相似文献
18.
Sabri Cevik Bihter Şaşmaz Cengiz Yenikaya Ferdağ Çolak Musa Sari Orhan Büyükgüngör 《Russian Journal of Inorganic Chemistry》2010,55(4):494-500
The hydrothermal reaction of a mixture of V2O5, VCl3, 2,5-pyridinedicarboxylic acid and diluted H2SO4 for 68 h at 180°C gives a blue colored solution which yields prismatic blue crystals of IV 2 IV O2(SO4)2(H2O)6] (1) in 32% yield (based on V). Complex 1 was investigated by means of elemental analysis (C, H and S), TGA, FT-IR, manganometric titration, Single Crystal X-ray Diffraction Methods and also comparative antimicrobial activities. Crystal data for the compound: monoclinic space group P21/c and unit cell parameters are a = 7.3850(12) Å, b = 7.3990(7) Å, c = 12.229(2) Å, β = 108.976(12)° and Z = 2. Although structure of 1 as a natural mineral has been previously determined, this work covers new preparation method and full characterization of 1 along with comparison of antibacterial activity between 1 and the commercial vanadium(IV) oxide sulfate hydrate compounds, VOSO4 · xH2O (Riedel-de Haën and Alfa Aesar brand names). 1 was evaluated for the antimicrobial activity against gram-positive, gram-negative bacteria, yeasts and mould compared with the commercial VOSO4 · xH2O compounds. 1 showed weak activity against bacteria Bacillus cereus, Nocardia asteroides and yeast Candida albicans. A good antimicrobial activity was recorded against Cirtobacter freundii (15 mm). There are only a few reproducible well-defined vanadium(IV) starting materials to use for exploring the synthesis of new materials. VCl4, VO(acac)2, VOSO4 · xH2O and [V(IV)OSO4(H2O)4] · SO4 · [H2N(C2H4)2NH2] are common starting materials for such applications. In addition to these compounds, 1 can be used as an oxovanadium precursor. 相似文献
19.
Xiangzhong Ren Yingkai Jiang Peixin Zhang Jianhong Liu Qianling Zhang 《Journal of Sol-Gel Science and Technology》2009,51(2):133-138
One-dimensional (1D) submicron-belts of V2O5 have been prepared by a sol–gel route using V2O5, H2O2 and aniline as starting materials. Thermogravimetric and differential thermal analysis, X-ray diffraction, Fourier transform
infrared spectroscopy and scanning electron microscopy were employed to characterize the samples. Electrochemical behaviors
as cathode material in rechargeable lithium-ion batteries were investigated by galvanostatic charge–discharge measurement
and cyclic voltammeter. The results showed that the synthesized V2O5 appeared to be submicron-belts and orthorhombic structure. The V2O5 submicron-belts exhibited a high initial discharge capacity of 346 mAh/g and stayed 240 mAh/g after 20 cycles at 0.1 C discharge
rate in the potential region 1.8–4.0 V. 相似文献
20.
Sofia Nikolaou Daniela M. Tomazela Marcos N. Eberlin Henrique E. Toma 《Transition Metal Chemistry》2008,33(8):1059-1065
The polymetallic [Ru3O(CH3COO)6(py)2(BPE)Ru(bpy)2Cl](PF6)2 complex (bpy = 2,2′-bipyridine, BPE = trans-1,2-bis(4-pyridil)ethylene and py = pyridine) was assembled by the combination of an electroactive [Ru3O] moiety with a [Ru(bpy)2(BPE)Cl] photoactive centre, and its structure was determined using positive ion electrospray (ESI-MS) and tandem mass (ESI-MS/MS)
spectrometry. The [Ru3O(CH3COO)6(py)2(BPE)Ru(bpy)2Cl]2+ doubly charged ion of m/z 732 was mass-selected and subject to 15 eV collision-induced dissociation, leading to a specific dissociation pattern, diagnostic
of the complex structure. The electronic spectra display broad bands at 409, 491 and 692 nm ascribed to the [Ru(bpy)2(BPE)] charge-transfer bands and to the [Ru3O] internal cluster transitions. The cyclic voltammetry shows five reversible waves at −1.07 V, 0.13 V, 1.17 V, 2.91 V and
−1.29 V (vs SHE) assigned to the [Ru3O]−1/0/+1/+2/+3 and to the bpy0/−1 redox processes; also a wave is observed at 0.96 V, assigned to the Ru+2/+3 pair. Despite the conjugated BPE bridge, the electrochemical and spectroelectrochemical results indicate only a weak coupling
through the π-system, and preliminary photophysical essays showed the compound decomposes under visible light irradiation. 相似文献