共查询到20条相似文献,搜索用时 15 毫秒
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Eleonora Freire Sergio Baggio Ricardo Baggio Raúl Mariezcurrena 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(8):926-929
The title compounds, [Ni(S2O3)(C12H8N2)2]·0.92H2O·1.4CH4O and [Ni(S2O3)(C10H8N2)2]·2H2O·0.55CH4O, are monomeric, containing nickel(II) in a distorted octahedral coordination environment provided by the four N atoms of two bidentate bipy or phen groups and one S and one O atom from a chelating thiosulfate anion. The crystals are highly unstable outside their mother liquors and are stabilized in solution by a not fully determined number of water and methanol solvate molecules. The phenanthroline structure includes two independent moieties related by a non‐crystallographic inversion center. The thiosulfate anions display the usual S—O lengthening found when the anion acts in a bidentate mode. 相似文献
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《Journal of computational chemistry》2017,38(28):2411-2419
The excitation energy of Brooker's merocyanine in water–methanol mixtures shows nonlinear behavior with respect to the mole fraction of methanol, and it was suggested that this behavior is related to preferential solvation by methanol. We investigated the origin of this behavior and its relation to preferential solvation using the three‐dimensional reference interaction site model self‐consistent field method and time‐dependent density functional theory. The calculated excitation energies were in good agreement with the experimental behavior. Analysis of the coordination numbers revealed preferential solvation by methanol. The free energy component analysis implied that solvent reorganization and solvation entropy drive the preferential solvation by methanol, while the direct solute–solvent interaction promotes solvation by water. The difference in the preferential solvation effect on the ground and excited states causes the nonlinear excitation energy shift. © 2017 Wiley Periodicals, Inc. 相似文献
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Orhan Büyükgüngr Mustafa OdabasÛoglu 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(11):o691-o692
In the title compound, 2C5H7N2+·C4H4O42?·C4H6O4, cyclic eight‐membered hydrogen‐bonded rings exist involving 2‐aminopyridinium and succinate ions. The succinic acid and succinate moieties lie on inversion centres. Succinic acid molecules and succinate ions are linked into zigzag chains by O—H?O hydrogen bonds, with O?O distances of 2.6005 (16) Å. 相似文献
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Observations on the thermoreversible gelation of two-directional arborols in water–methanol mixtures
Keunok Han Yu Paul S. Russo Laura Younger William G. Henk Duen-Wu Hua George R. Newkome Gregory Baker 《Journal of Polymer Science.Polymer Physics》1997,35(17):2787-2793
Reversible gels of two-directional cascade polymers with hydrophilic groups covalently attached by an hydrophobic center chain were studied by light and small-angle X-ray scattering, differential scanning calorimetry, and freeze-fracture transmission electron microscopy. The long, self-assembled fibers interact side-by-side over extended regions to form bundles. A given fiber may participate in several bundles, thus forming a three-dimensional gel network. © 1997 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 35: 2787–2793, 1997 相似文献
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Orhan Büyükgüngr Mustafa Odabaolu idem Albayrak Peter Lnnecke 《Acta Crystallographica. Section C, Structural Chemistry》2004,60(7):o470-o472
The title complex, 2C5H7N2+·C4H2O42−·C4H4O4, contains cyclic eight‐membered hydrogen‐bonded rings involving 2‐aminopyridinium and fumarate ions. The fumaric acid molecules and fumarate ions lie on inversion centers and are linked into zigzag chains by O—H⋯O hydrogen bonds. The dihedral angle between the pyridinium ring and the hydrogen‐bonded fumarate ion is 7.60 (4)°. The fumarate anion is linked to the pyridinium cations by intermolecular N—H⋯O hydrogen bonds. The heterocycle is fully protonated, thus enabling amine–imine tautomerization. 相似文献
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Dong-Wook Lee Sang-Jun Park Chang-Yeol Yu Son-Ki Ihm Kew-Ho Lee 《Journal of membrane science》2008,316(1-2):63-72
When a methanol reforming–membrane reactor is employed as a hydrogen generator for proton exchange membrane fuel cell (PEMFC), three important aims should be simultaneously achieved in one process, which are methanol conversion improvement, high hydrogen recovery, and high CO removal efficiency. To achieve the aims, we investigated five different configurations of a membrane reactor (a methanol reforming–microporous membrane (MMi) reactor, methanol reforming–mesoporous membrane (MMe) reactor, methanol reforming–mesoporous membrane–water–gas shift (MMeW) reactor, methanol reforming–macroporous membrane (MMa) reactor and methanol reforming–macroporous membrane–water–gas shift (MMaW) reactor). As a result, the MMi reactor was not suitable for a hydrogen carrier of PEMFC due to low hydrogen recovery. The MMe and MMa reactor showed low CO removal efficiency due to low permselectivity of the mesoporous and macroporous membrane. In contrast, the MMeW and MMaW reactor gave simultaneously methanol conversion improvement, high hydrogen recovery, and high CO removal efficiency in one process. The low CO removal efficiency due to low permselectivity of the mesoporous and macroporous membrane was significantly enhanced by the water–gas shift reaction in the permeate side of the MMeW and MMaW reactor. In addition, based on the reaction results in the MMi, MMe and MMa reactor, it was confirmed that methanol conversion in a membrane reactor system is higher as a membrane used in a membrane reactor has higher total permeance difference (∑permeance of products − ∑permeance of reactants). 相似文献
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M. Barboiu A. van der Lee 《Acta Crystallographica. Section C, Structural Chemistry》2003,59(9):m366-m368
The structure of the supramolecular complex calcium–trifluoromethanesulfonate–1,3‐di‐4‐pyridylurea–methanol (1/2/2/4), Ca2+·2CF3SO3−·2C11H10N4O·4CH4O, is presented. The Ca2+ ion lies on an inversion centre and is octahedrally coordinated by four methanol molecules and two trifluoromethanesulfonate counter‐ions. The molecular packing is dominated by hydrogen‐bonded sheets in the (110) plane which contain R(32) rings; in these rings, significant π–π interactions are observed between inversion‐related 1,3‐di‐4‐pyridylurea molecules. 相似文献