Zur Chemie von Uranylvanadaten mit Trimetavanadationen und Schichtstruktur (Uvanit) / The Chemistry of Uranylvanadates with Trimetavanadate Ions and Layer Structure (Uvanite)

1973 ◽  
Vol 28 (5-6) ◽  
pp. 239-245 ◽  
Author(s):  
Klaus Jürgen Hilke ◽  
Ulrich Grosse-Brauckmann ◽  
Gerhard Lagaly ◽  
Armin Weiss
Keyword(s):  
Ethylene Glycol ◽  
Layer Structure ◽  
Organic Cations ◽  
Water Molecules ◽  
Solvent Molecules ◽  
Inorganic And Organic

Synthesis and properties of an uranylvanadate (Mz+1/z (H2O)π [UO2V3O9]-) with trimetavanadate ions are described. The compound has a layer structure with [UO2V3O9]--layers of about 6.5 Å thickness. The layers are identical with the U, V-layers in natural uvanite. The cations Mz+ between the [UO2V3O9]--layers can be exchanged against inorganic and organic cations. The water molecules can be replaced by other solvent molecules (nitromethane, acetonitrile, dimethylsulfoxide, N-methylformamide, ethylene glycol etc.) under formation of distinct layer solvates. Reversible dehydration of the hydrates between 100° and 500°C leads to regular displacements of the uvanite layers to each other.

scholarly journals The Intercalation of CORM-2 with Pharmaceutical Clay Montmorillonite (MMT) Aids for Therapeutic Carbon Monoxide Release

2019 ◽  
Vol 20 (14) ◽  
pp. 3453 ◽  
Author(s):  
Muhammad Faizan ◽  
Kifayat Ullah Khan Niazi ◽  
Niaz Muhammad ◽  
Yongxia Hu ◽  
Yanyan Wang ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Layer Structure ◽  
Xrd Analysis ◽  
Water Molecules ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Ruthenium Carbonyl ◽  
Solvent Molecules ◽  
First Time

The pharmaceutical clay montmorillonite (MMT) is, for the first time, explored as a carbon monoxide-releasing material (CORMat). MMT consists of silicate double layered structure; its exfoliation feature intercalate the CORM-2 [RuCl(μ-Cl)(CO)3]2 inside the layers to suppress the toxicity of organometallic segment. The infrared spectroscopy (IR) confirmed the existence of ruthenium coordinated carbonyl ligand in MMT layers. The energy-dispersive X-ray spectroscopy (EDX) analysis showed that ruthenium element in this material was about 5%. The scanning electron microscopy (SEM) and transmission electron microscope (TEM) images showed that the layer-structure of MMT has been maintained after loading the ruthenium carbonyl segment. Moreover, the layers have been stretched out, which was confirmed by X-ray diffraction (XRD) analysis. Thermogravimetric (TG) curves with huge weight loss around 100–200 °C were attributed to the CO hot-release of ruthenium carbonyl as well as the loss of the adsorbed solvent molecules and the water molecules between the layers. The CO-liberating properties have been assessed through myoglobin assay. The horse myoglobin test showed that the material could be hydrolyzed to slowly release carbon monoxide in physiological environments. The half-life of CO release was much longer than that of CORM-3, and it has an excellent environmental tolerance and slow release effect.

scholarly journals Crystal structures of two decavanadates(V) with pentaaquamanganese(II) pendant groups: (NMe4)2[V10O28{Mn(H2O)5}2]·5H2O and [NH3C(CH2OH)3]2[V10O28{Mn(H2O)5}2]·2H2O

2015 ◽  
Vol 71 (2) ◽  
pp. 146-150 ◽  
Author(s):  
Maurício P. Franco ◽  
André Luis Rüdiger ◽  
Jaísa F. Soares ◽  
Giovana G. Nunes ◽  
David L. Hughes
Keyword(s):  
Hydrogen Bonding ◽  
Hydrogen Bonds ◽  
Three Dimensional ◽  
Organic Cations ◽  
Water Molecules ◽  
Hydroxyl Groups ◽  
Reaction Conditions ◽  
Hydrogen Bonding Networks ◽  
Solvent Molecules ◽  
Decavanadate Cluster

Two heterometallic decavanadate(V) compounds, bis(tetramethylammonium) decaaquadi-μ4-oxido-tetra-μ3-oxido-hexadeca-μ2-oxido-hexaoxidodimanganese(II)decavanadate(V) pentahydrate, (Me4N)2[V10O28{Mn(H2O)5}2]·5H2O,A, and bis{[tris(hydroxymethyl)methyl]ammonium} decaaquadi-μ4-oxido-tetra-μ3-oxido-hexadeca-μ2-oxido-hexaoxidodimanganese(II)decavanadate(V) dihydrate, [NH3C(CH2OH)3]2[V10O28{Mn(H2O)5}2]·2H2O,B, have been synthesized under mild reaction conditions in an aqueous medium. Both polyanions present two [Mn(OH2)5]2+complex units bound to the decavanadate cluster through oxide bridges. InA, the decavanadate unit has 2/msymmetry, whereas inBit has twofold symmetry. Apart from this, the main differences betweenAandBrest on the organic cations, tetramethylammonium and [tris(hydroxymethyl)methyl]ammonium, respectively, and on the number and arrangement of the water molecules of crystallization. In both compounds, the H atoms from the coordinating water molecules participate in extensive three-dimensional hydrogen-bonding networks, which link the cluster units both directly and through solvent molecules and, inB, through the `tris' cation hydroxyl groups. The cation inBalso participates in N—H...O hydrogen bonds. A number of C—H...O interactions are also observed in both structures.

scholarly journals Optimal Relabeling of Water Molecules and Single-Molecule Entropy Estimation

Biophysica ◽  
2021 ◽  
Vol 1 (3) ◽  
pp. 279-296
Author(s):  
Federico Fogolari ◽  
Gennaro Esposito
Keyword(s):  
Single Molecule ◽  
Degrees Of Freedom ◽  
Water Molecules ◽  
Maximum Information ◽  
Nearest Neighbours ◽  
Biomolecular Simulations ◽  
Solvent Molecules ◽  
Solvation Entropy ◽  
Dynamics Simulations ◽  
Internal Degrees Of Freedom

Estimation of solvent entropy from equilibrium molecular dynamics simulations is a long-standing problem in statistical mechanics. In recent years, methods that estimate entropy using k-th nearest neighbours (kNN) have been applied to internal degrees of freedom in biomolecular simulations, and for the rigorous computation of positional-orientational entropy of one and two molecules. The mutual information expansion (MIE) and the maximum information spanning tree (MIST) methods were proposed and used to deal with a large number of non-independent degrees of freedom, providing estimates or bounds on the global entropy, thus complementing the kNN method. The application of the combination of such methods to solvent molecules appears problematic because of the indistinguishability of molecules and of their symmetric parts. All indistiguishable molecules span the same global conformational volume, making application of MIE and MIST methods difficult. Here, we address the problem of indistinguishability by relabeling water molecules in such a way that each water molecule spans only a local region throughout the simulation. Then, we work out approximations and show how to compute the single-molecule entropy for the system of relabeled molecules. The results suggest that relabeling water molecules is promising for computation of solvation entropy.

Restricted Rotational Motion of InterlayerWaterMolecules in Vanadium Pentoxide Hydrate, V2O5·n D2O, as Studied by Deuterium NMR

2002 ◽  
Vol 57 (6-7) ◽  
pp. 419-424 ◽  
Author(s):  
Sadamu Takeda ◽  
Yuko Gotoh ◽  
Goro Maruta ◽  
Shuichi Takahara ◽  
Shigeharu Kittaka
Keyword(s):  
Double Layer ◽  
Vanadium Pentoxide ◽  
Rotational Motion ◽  
Interlayer Space ◽  
Layer Structure ◽  
Bond Distance ◽  
Adsorbed Water ◽  
Deuterium Nmr ◽  
Water Molecules ◽  
Layer Structures

The rotational behavior of the interlayer water molecules of deuterated vanadium pentoxide hydrate, V2O5.nD2O, was studied by solid-state deuterium NMR for the mono- and double-layer structures of the adsorbed water molecules. The rotational motion was anisotropic even at 355 K for both the mono- and double-layer structures. The 180° flipping motion about the C2-symmetry axis of the water molecule and the rotation around the figure axis, which makes an angle Ɵ with the C2-axis, occurred with the activation energy of (34±4) and (49±6) kJmol-1, respectively. The activation energies were almost independent of the mono- and double-layer structures of the water molecules, but the angle Ɵ made by the two axes varied from 33° for the monolayer to 25° for the double-layer at 230 K. The angle started to decrease above 250 K (e. g. the angle was 17 at 355 K for the double-layer structure). The results indicate that the average orientation of the water molecules in the two dimensional interlayer space depends on the layer structure and on the temperature. From the deuterium NMR spectrum at 130 K, the quadrupole coupling constant e2Qq/h = 240 kHz and the asymmetry parameter η= 0.12 were deduced. These values indicate the average hydrogen bond distance R(O H) = 2.0 Å for the D2O molecules in the 2D-interlayer space

Quantum chemical calculation of cation interaction with water molecules and ethylene glycol

2007 ◽  
Vol 48 (1) ◽  
pp. 166-169 ◽  
Author(s):  
A. G. Rozhkova ◽  
E. V. Butyrskaya ◽  
M. V. Rozhkova ◽  
V. A. Shaposhnik
Keyword(s):  
Ethylene Glycol ◽  
Quantum Chemical Calculation ◽  
Quantum Chemical ◽  
Water Molecules ◽  
Chemical Calculation

scholarly journals 1-(4-Hydroxyphenyl)piperazine-1,4-diium tetrachloridocobalt(II) monohydrate

2014 ◽  
Vol 70 (2) ◽  
pp. m75-m75 ◽  
Author(s):  
Marwa Mghandef ◽  
Habib Boughzala
Keyword(s):  
Hydrogen Bonds ◽  
Water Molecule ◽  
Three Dimensional ◽  
Organic Cations ◽  
Water Molecules ◽  
Asymmetric Unit ◽  
Hybrid Compound ◽  
Organic Hybrid ◽  
Compound C ◽  
Dimensional Network

The asymmetric unit of the title inorganic–organic hybrid compound, (C10H16N2O)[CoCl4]·H2O, consists of a tetrahedral [CoCl4]2−anion, together with a [C10H18N2O]2+cation and a water molecule. Crystal cohesion is achieved through N—H...Cl, O—H...Cl and N—H...O hydrogen bonds between organic cations, inorganic anions and the water molecules, building up a three-dimensional network.

scholarly journals Solvent influence on intramolecular interactions and aromaticity in meta and para nitroanilines

2020 ◽  
Vol 31 (5) ◽  
pp. 1717-1728
Author(s):  
Krzysztof K. Zborowski ◽  
Halina Szatyłowicz ◽  
Tadeusz M. Krygowski
Keyword(s):  
Cluster Model ◽  
Density Functional ◽  
Intramolecular Interactions ◽  
Water Molecules ◽  
Amino Groups ◽  
Functional Theory ◽  
Hydration Effect ◽  
Solvent Influence ◽  
Solvation Models ◽  
Solvent Molecules

Abstract Theoretical density functional theory (B3LYP/6-31G**) was used to study the intra- and intermolecular interactions of nitrobenzene, aniline, and meta and para nitroaniline in various solvation models. The studied molecules were solvated by one or two water molecules in the presence of continuum solvation (the PCM model) or without it. Finally, the studied molecules were surrounded by a cluster of water molecules. For comparison, calculations were also made for separated molecules. Geometries, energies, hydrogen bonding between solutes and solvent molecules, atomic charges, and aromaticity were examined. The analysis was based on the Atoms in Molecules methodology and the Harmonic Oscillator Model of Aromaticity (HOMA) index. As a result, an extensive description of the solvation of nitro and amino groups and the effect of solvation on mutual interactions between these groups in meta and para nitroanilines is provided. It was found that in general, the PCM description of the hydration effect on the electronic structure of the studied systems (substituents) is consistent with the approach taking into account all individual interactions (cluster model).

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