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11.
Li6[TeMo6O24] · 18 H2O is triclinic (space group P1 , a = 1 041.7(1), b = 1 058.6(1), c = 1 070.8(1) pm, α = 61.08(1), β = 60.44(1), γ = 73.95(1)°). Single crystal X-ray structure analysis (Z = 1, 295 K, 317 parameters, 3 973 reflections, Rg = 0.0250) revealed an infinite branched chain of edge-sharing Li coordination polyhedra to be the prominent structural feature. One of the four crystallographically independent Li+ is coordinated octahedrally. The coordination polyhedra of the remaining Li+ are distorted trigonal bipyramids. Only three unique oxygen atoms (O(9), O(10), O(12)) of the centrosymmetric [TeMo6O24]6? anion are bound to Li+. The further positions in the coordination spheres of the Li+ are occupied by water molecules. Intermolecular hydrogen bonds involve mainly oxygen atoms of the [TeMo6O24]6? anion as nearly equivalent proton acceptors without regard to their different bonding modes to Te and Mo, respectively. Li6[TeMo6O24] · Te(OH)6 · 18 H2O crystallizes monoclinically in space group P21/n with Z = 4, a = 994.1(3), b = 2 344.8(10), c = 1 764.9(4) pm, and β = 91.36(4)°. Single crystal structure analysis with least squares refinement of 627 parameters (5 900 reflections, 295 K) converged to Rg = 0.0324. There are six unique Li+ cations. The coordination polyhedra of Li(1), Li(2), Li(3), and Li(4) are linked by common edges to yield an eight membered centrosymmetric strand. The coordination polyhedra of the remaining two Li+ sites (Li(5), Li(6)) are connected to a dimeric unit via a common corner. All oxygen atoms of the Te(OH)6 molecule are involved in the coordination of Li+. However, only three oxygen atoms (O(13), O(18), O(23)) of the [TeMo6O24]6? anion which lacks crystallographic symmetry are involved in the coordination of Li+. The oxygen atoms of the anion act as proton acceptors in hydrogen bonds of predominantly medium strength. Te(OH)6 molecules and [TeMo6O24]6? anions connected by strong hydrogen bonds form an infinite chain. 相似文献
12.
Reaction of 3-hydrazonobutan-2-one oxime with aromatic aldehydes resulted in the formation of 1,2-bis(arylidene)hydrazine commonly referred as azine as an unexpected product, instead of expected product 3-(aryl)methylenehydrazonobutan-2-one oxime, which were subsequently oxidized to corresponding aromatic acids with an ecofriendly oxidizing agent iodobenzene diacetate. Azines and carboxylic acids were characterized by IR and NMR (1H, 13C, HMBC, and HMQC) studies. 相似文献
13.
Waleed A. El‐Said Mona A. Abdel‐Rahman Eman M. Sayed Aboel‐Magd A. Abdel‐Wahab 《Electroanalysis》2019,31(5):829-837
Here, we reported on a one‐step fabrication of magnetite Fe3O4 nanoparticles/indium tin oxide (ITO) electrode based on the direct growing of Fe3O4 nanoparticles on the ITO surface by using a solvothermal process. The modified electrode was used as electrochemical methotrexate (MTX) biosensor with high sensitivity based on cyclic voltammetry and square wave voltammetry techniques. The results demonstrated a linear relationship between the MTX concentration and its oxidation current peak over a wide range from 10?5 to 10?14 mole/L with a limit of detection of 0.4×10?15 M based on the square wave voltammetry (SWV) technique. In addition, Fe3O4/ITO electrode showed a good capability for measuring very low concentrations of MTX drug dissolved in human serum solution. Also, Fe3O4/ITO electrode was used for detecting MTX in blood serum samples collected from patients after their treatment with MTX. The prepared electrode showed the higher sensitivity that higher than the Viva‐E instrument, which opens the door for developing a cheap, simple and higher sensitive MTX sensor. 相似文献
14.
Fatma El-Mariah Mona Hosny Ali Deeb 《Phosphorus, sulfur, and silicon and the related elements》2013,188(11):2505-2517
A series of 3-substituted pyridazino[3′,4′:3,4]pyrazolo[5,1-c]-1,2,4-triazens have been synthesized starting from the 3-carboxylic acid derivative 2. The reaction of the acid chloride 3 with amines gave the corresponding anilides 4. The reaction of 2 with ethyl chloroformate and sodium azide in the presence of triethyl amine gave the carbonyl azide 5, which underwent a Curtius rearrangement in boiling ethanol to afford the carbamate 6, which converted to the 3-amino derivative 7 upon alkaline hydrolysis, and the reaction with acid chloride resulted in N-substituted products 9. On other hand, the reaction of the carboxylic acid 2 with POCl3 and thiosemicarbazide afforded 2-amino-1,3,4-thiadiazole derivative 13. The condensation of 13 with aldehydes furnished 14 in a good yield. The products were screened for their antimicrobial activity against six microorganisms. 相似文献
15.
Several N-alkyl/aryl-Se-alkyl/(aryl)selenocarbamates were prepared from various isocyanates and diselenides by reductive cleavage of Se-Se bond with the Zn/AlCl3 system in dry acetonitrile at 80℃. 相似文献
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Lok Kumar Shrestha 《Journal of Dispersion Science and Technology》2013,34(8):1236-1241
We have investigated the phase behavior of diglycerol monomyristate (DGM) in a variety of organic solvents over a wide range of temperatures and compositions. At lower temperature, there exists a surfactant solid, which solubilize different amounts of oils depending on the oil nature. The melting temperature of the solid phase is virtually constant in a wide range of composition. In all the systems, a lamellar liquid crystal (Lα) is formed in surfactant‐rich regions at intermediate temperatures between the solid‐melt and isotropic two‐ or single‐phase regions. In the dilute regions reverse vesicles are formed in the Lα+O regions mainly in the case of linear hydrocarbon type oils. In the aromatic and cyclic aliphatic oils, there are isotropic solutions at 25°C. However, there is dispersion of α‐solid in the case of liner hydrocarbon oils. Two liquid‐phase regions above the Lα phase are observed in the case of tetradecane and hexadecane. In the shorter chain oil systems, such as octane and decane, no two liquid‐phase appear above Lα region. That is the two liquid‐phase region is largely dependent on the chain length of the oils, and becomes wider in longer hydrocarbon oil. 相似文献