Ionic conductivity of epitactic MBE-grown BaF2 films

We studied parallel conductivities of pure BaF₂ films with thicknesses ranging from 35 to 300 nm, epitaxially grown on Al₂O₃(0 1 2) substrates by molecular beam epitaxy technique. The overall conductivities of the films are found to increase with decreasing thickness. The detailed investigation of the overall conductance as a function of the thickness permits the deconvolution of bulk and boundary effects, the latter being attributed to distinct space charge effects in the interface between BaF₂ film and Al₂O₃ substrate. The (extrinsic) Debye length (λ) is estimated to be about 8 nm at T=593 K, which corresponds to an impurity content of 10¹⁸/cm³ (singly ionized dopant assumed). This is consistent with the fact that we observed a constant boundary contribution for all investigated films (film thickness >4λ). It is also consistent with the Debye length observed in a previous report on CaF₂/BaF₂ heterolayers fabricated by the same technique, in which the low temperature enhancement was also attributed to space charges in BaF₂ [Nature 408 (2000) 946]. Only at low temperatures (below 370 °C), the conductance seems to be influenced by strain effect.     

Kinetically Controlled Solid State Reactions in the System InCl/SnCl2

This paper reports on studies on the reaction of InCl with SnCl₂ to form ternary halides. The reaction route is investigated by x‐ray investigations at different temperatures. Depending on the modification of InCl as educt and on the temperature conditions the reaction follows different pathways which may include intermediate redox reactions of the type In⁺ + Sn²⁺ → In³⁺ + Sn⁰.     

Cs[Er6C]I12 und Cs2Lu[Lu6C]Cl18: Beispiele für quaternäre reduzierte Halogenide der Lanthanide mit isolierten „Clustern”︁

CS[Er₆C]I₁₂ and cs₂Lu[Lu₆C]CI₁₈: Examples for Quaternary Reduced Halides of the Lanthanides with Isolated “Clusters” Cs[Er₆C]I₁₂ and Cs₂Lu[Lu₆C]Cl₁₈ were obtained as byproducts through metallothermic reductions of ErI₃ and LuCl, with cesium in the presence of carbon in sealed tantalum containers at temperatures ranging from 700 to 940 °C. Cs₂Lu[Lu₆C]Cl₁₈ (isostructural with Cs₂Zr[Zr₆H]Cl₁₈, R 3 , a = 981.7 pm, c = 2723.2 pm, Z = 3, R = 0.082, R, = 0.053) contains octahedral [Lu₆C] clusters which are slightly compressed along the threefold axis and edge-bridged by twelve chloride anions to form [Lu₆C]Cl₁₂ units. Six additional Cl in exo positions of the cluster provide octahedral coordination for the seventh Lu³⁺. Cs⁺ occupies anticuboctahedral interstices within the Cl⁺ layers as a part of the (hexagonal) closest packed arrangement. Cs[Er₆C]I₁₂ (trigonal, R 3, a = 1112.0pm, c = 2063.8pm, Z = 3, R = 0.094, R, = 0.068) exhibits [Er₆C]I₁₂ units as well and shows the structural framework of Sc[Sc₆N]Cl₁₂. Instead of Sc³⁺ in octahedral holes, cesium occupies a regular iodide position within the ccp sheets forming [CsI₃] layers. Both halides are compared with other compounds of the lanthanides containing isolated [M₆X₁₂] clusters. The extreme electron deficiency is discussed.     

Ternäre Halogenide vom Typ A3MX6. IV. [1]. Ternäre Halogenide des Scandiums mit Natrium,Na3ScX6 (X = F,Cl, Br): Synthese,Strukturen, Ionenleitfähigkeit

Ternary Halides of the A₃MX₆ Type. IV. Ternary Halides of Scandium with Sodium, Na₃ScX₆ (X = F, Cl, Br): Synthesis, Structures, Ionic Conductivity X-ray studies on single crystals of Na₃ScF₆ and Na₃ScBr₆ show, that Na₃ScF₆ crystallizes with the cryolite type (monoclinic, P2₁/n, Z = 2, a = 560.16(9), b = 580.31(8), c = 812.1(2)pm, β = 90.720(14)°) and Na₃ScBr₆, as the only ternary bromide of the rare earth elements with sodium, in the Na₃CrCl₆ type (trigonal, P3 1c, Z = 2, a = 728.95(7), c = 1309.29(17)pm). The ionic conductivity of powder samples of Na₃ScF₆, Na₃ScBr₆ and of Na₃ScCl₆ was studied by impedance spectroscopy. Activation energies were determined as 1.22 eV, 0.80 eV and 0.71 eV for the fluoride, chloride and bromide, respectively. The differences are explained from the crystal structures and the sizes and polarizabilities of the anions.     

Synthesis and In-silico Simulation of Some New Bis-thiazole Derivatives and Their Preliminary Antimicrobial Profile: Investigation of Hydrazonoyl Chloride Addition to Hydroxy-Functionalized Bis-carbazones

Two new series of bis-thiazoles 6a-f and bis-thiazolones 9a-d were prepared via reacting bis-thiosemicarbazone 3 with hydrazonoyl chloride derivatives 4a-f and 7a-d, respectively, in dioxane under basic conditions. Another group of bis-thiazole derivatives 12a-h was prepared by reacting bis-thiosemicarbazone 3 with each of phenacyl bromide derivatives 10a-h under a similar reaction protocol. A plausible mechanism was proposed. Structural elucidation of the new products was established using both elemental and spectrometric/spectroscopic analyses. Structural, electronic, and the pharmacological characteristics of the prepared molecules were investigated with DFT calculations. Antibacterial and antifungal activities of the new bis-thiazoles were screened and compared with vancomycin and amphotericin B as antimicrobial standards. Molecular docking studies on the promising candidate compounds, with the lowest minimum inhibitory concentrations (MIC), were performed with SAP2 of C. albicans and FabI of S. aureus and P. aeruginosa.     

An Efficient Method for Preparing the α-Deuterated-α,β-Unsaturated Carbonyl Compounds by Reaction of Stable Phosphonium Ylides with Carbonyl Compounds in Deuterium Oxide

Carbonyl compounds reacted with stable phosphonium ylides in D₂O to give α-deuterated-α,β-unsaturated carbonyl compounds in the same flask. The chemical yield and deuterium incorporation are excellent under our procedure. The fragile group like ozonide was compatible with our reaction condition.     

Reactions of Hydrazonoyl Halides 33 1 : Synthesis of Some New 2,3-Dihydro-1,3,4-thiadiazoles Containing Pyrazol-3-yl,Indolin-2-one-2-yl and Indan-1,3-dione-2-yl Moieties

Some new 2,3-dihydro-1,3,4-thiadiazoles containing pyrazol-3-yl, indolin-2-one-2-yl and indan-1,3-dione-2-yl moieties in a good yields obtained from the reaction of hydrazonoyl halides with thiocarbamate and carbodithioate in ethanolic triethylamine respectively. In contrast, pyrazolylthiourea reacts with hydrazonoyl halides under the same condition afford corresponding hydrazonoyl sulfide derivatives.     

Fluorinated azole anticancer drugs: Synthesis,elaborated structure elucidation and docking studies

The present article deals with the synthesis of novel nano-sized fluorinated thiazoles and studying their anticancer potentiality. The targeted azoles could be accessed via trifluoro-methylated thiosemicarbazone (3) prepared by reaction of with thiosemicarbazide in acidic solution of ethanol. The latter a fluorinated building block (3) have been reacted with appropriate derivatives of a-halo compounds namely, N-aryl 2-oxopropane-hydrazonoyl chlorides 4a-f using dioxane containing TEA as base catalyst. Also, the reaction between N-(4-(1-(2-carbamothioylhydrazineylidene)ethyl)phenyl)-2,2,2-trifluoroacetamide (3) and chloroacetonitrile 8 under the same experimental conditions furnished the corresponding amino thiazole derivative 11. In the same manner the base catalyzed cyclocondensation reaction between N-(4-(1-(2-carbamothioylhydrazineylidene)ethyl)phenyl)-2,2,2-trifluoroacetamide (3) and phenacyl bromide derivatives 12a-d afforded the corresponding thiazoles 13a-d in good yield. The structure of all synthesized thiazole derivatives as well as their mechanistic pathways were studied based on spectral data analysis and physical characteristics. The nanosized products were confirmed by using XRD analysis. Moreover, twelve samples were submitted for evaluation of their cytotoxicity activities against MDA-MB-231 (breast cancer cell) using colorimetric MTT assay, in comparison with Cisplatin standard drug. Two nano-sized thiosemicarbazone derivative 3 and the thiazole derivative 7c showed potent activity with IC₅₀ = 7.7 and 2.97 µg/ml, respectively in compared with the IC₅₀ = 4.33 µg/ml of cisplatin. The nanosized thiazole derivative 7c was more potent than cisplatin. Also, two thiazole derivatives 13b and 7b showed good activity with IC₅₀ = 13.4 and 14.9 µg/ml. In addition, the molecular docking studies have been achieved using 4hy0, (X-chromosome-linked- inhibitor of apoptosis protein; (XIAP)).     

Electrochemical Detection of Anions on an Electrophoresis Microchip with Integrated Silver Electrode

A poly(dimethylsiloxane)/glass hybrid microfluidic chip with integrated silver electrode is described for electrochemical detection of anions. The working electrode was directly fabricated on a glass slide and the chip formed by reversibly sealing of a PDMS slab with microchannels to the slide. Under an alkaline phosphate condition, thiocyanide and three halides were sensitively detected. Factors influencing the separation and detection procedure were discussed and optimized. Linear responses over two magnitudes were obtained with limit of detection at the micromolar level.