The Ru(II) complexes cis-[Ru(L)Cl2] (C1-C3) of novel tetradentate NSNN ligands (L) {where L is C5H4N-CH2-S-C6H4NC(COCH3)-NN-C6H4X, and X is H (L1), CH3 (L2) and Br (L3)}, were synthesized and characterized by spectroscopy (IR, UV/vis and NMR), cyclic voltammetry and crystallography. The tetradentate ligands were isolated as the amidrazones H2L {where H2L is C5H4N-CH2-S-C6H4NH-C(COCH3)N-NH-C6H4X and X is H (H2L1), CH3 (H2L2) and Br (H2L3)} as shown by crystallography of H2L1, but oxidize to azoimines during the formation of the Ru(II) complexes. A crystallographic analysis of C1 showed that the Ru(II) centre is in a distorted octahedral coordination sphere in which the tetradentate ligand occupies three equatorial sites and one axial site (two azoimine nitrogens and a thio sulfur in the equatorial plane and an axial pyridine nitrogen) and two chlorides occupying axial and equatorial coordination sites. The Ru(II) oxidation state is greatly stabilized by the novel tetradentate ligand, showing Ru(III/II) couples ranging from 1.43 to 1.51 V. The absorption spectrum of C1 in acetonitrile was modelled by time-dependent density functional theory. 相似文献
Low calcium oxalate urinary stones from the kidney, bladder, and ureter have been collected from the arid area (Taif, Saudi Arabia). After careful washing and drying of the collected stones, the samples were converted into a contamination-free homogenous fine powder with a particles' size smaller than 50 μm. The processed urinary stone powders were studied using attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), laboratory setup and synchrotron radiation X-ray diffraction (XRD), and energy-dispersive X-ray fluorescence (EDXRF). The activated function groups, quantitative phase analysis, and the semi-quantitative elemental analysis of the present urinary stones were identified. Seventeen elements were measured in most of the urinary stone samples. The significant elements are Ca, P, S, Cl, Zn, K, Fe, and Cu, whereas other elements were found alternatively in a few number of urinary stone samples. It was recognized that Ca exists with low concentration, which indicates the presence of different calcium phases even with low percentages. In 33% of the urinary stones, the phosphorus (P) was not measured, but there were high concentrations of sulfur (S) and low concentrations of Ca up to 2.15 ± 0.05%. The ATR-FTIR results indicate that the most compounds of the present urinary stones were urea and cystine combined with low ratios of calcium oxalate and calcium phosphate compounds. The quantitative phase analysis of the XRD of selected samples proves the presence of the cystine, urea, and calcium oxalate phases with different weight percent. 相似文献
A sensitive and simple method based on two-phase liquid-phase microextraction in porous hollow fiber followed by gas chromatography-flame ionization detection was developed for quantification and pharmacokinetic study of valproic acid (VPA, an antiepileptic drug) in rat plasma after oral administration of pure sodium valproate (25 mg kg−1). Some parameters such as type of organic solvent, pH of sample solution, stirring speed, salt addition, extraction time, and volume of sample that affected extraction efficiency of VPA were optimized. Under optimized microextraction conditions, VPA was extracted with 10 μL 1-octanol from 0.5 mL rat plasma previously diluted with 4.5 mL acidified and salinated water (pH 2) using 1-octanoic acid as internal standard. The limit of detection was 17 ng mL−1 with linear response over the concentration range of 50–10,000 ng mL−1 with correlation coefficient higher than 0.998. The developed method was successfully applied to determination of pharmacokinetic parameters such as tmax (peak time in concentration–time profile), Cmax (peak concentration in concentration–time profile), t1/2 (elimination half-life), AUC0–t (area under the curve for concentration versus time), clearance, and apparent distribution volume in rats following oral administration of VPA.
In the present study, (i) the classical Von Kárman theory, (ii) the first-order shear deformation theory and (iii) the higher-order (third-order) shear deformation theory are compared for studying the nonlinear forced vibrations of isotropic and laminate composite rectangular plates. In particular, the harmonic response in the frequency neighborhood of the fundamental mode of rectangular plates is investigated and the response curves computed by using the three different theories are compared. The boundary conditions of the plates are simply supported with immovable edges. Geometric imperfections are taken into account. Calculations for isotropic and laminated composite plates are presented and results are discussed. For isotropic plates, the frequency-response curves for large-amplitude vibrations obtained by using the three theories are almost coincident. For laminated composite plates, differences arise for relatively thick plates (ratio between the thickness and the edge equal to 0.1), while for thin plates (ratio between the thickness and the edge equal to 0.01), no difference is obtained. For all cases, the first-order shear deformation (with shear correction factor ) and the higher-order shear deformation theories give practically coincident results and differences are observed with respect to the classical Von Kárman theory. 相似文献
The aromatic polyketones 3a-d are versatile compounds for the synthesis of the multi-1,2,3-selenadiazole aromatic derivatives 1a-d. The preparation starts with the reaction between the multi-bromomethylene benzene derivatives 2a-d and 4-hydroxy- acetophenone to give compounds 3a-d which are transformed through the reaction with semicarbazide hydrochloride or ethyl hydrazine carboxylate into the corresponding semicarbazones derivatives 4a-d or hydrazones 5a-d. The reaction with selenium dioxide leads to regiospecific ring closure of semicarbazones or hydrazones to give the multi- 1,2,3-selenadiazole aromatic derivatives in high yield. 相似文献
A simple and sensitive dispersive liquid-liquid microextraction method for extraction and preconcentration of pentachlorophenol
(PCP) in water samples is presented. After adjusting the sample pH to 3, extraction was performed in the presence of 1% W/V
sodium chloride by injecting 1 mL acetone as disperser solvent containing 15 μL tetrachloroethylene as extraction solvent.
The proposed DLLME method was followed by HPLC-DAD for determination of PCP. It has good linearity (0.994) with wide linear
dynamic range (0.1–1000 μg L−1) and low detection limit (0.03 μg L−1), which makes it suitable for determination of PCP in water samples.
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The aim of this work is to identify numerically, for the first time, the time-dependent potential coefficient in a fourth-order pseudo-parabolic equation with nonlocal initial data, nonlocal boundary conditions, and the boundary data as overdetermination condition. This problem emerges significantly in the modeling of various phenomena in physics and engineering. From literature we already know that this inverse problem has a unique solution. However, the problem is still ill-posed by being unstable to noise in the input data. For the numerical realization, we apply the quintic B-spline (QB-spline) collocation method for discretizing the pseudo-parabolic problem and the Tikhonov regularization for finding a stable and accurate solution. The resulting nonlinear minimization problem is solved using the MATLAB subroutine lsqnonlin. Moreover, the von Neumann stability analysis is also discussed. 相似文献
Journal of Radioanalytical and Nuclear Chemistry - Nano ZnO is biosynthesized using Lactobcillus sp. Poly Acrylic acid-co-Acrylonitrile/ZnO, PAACAN/ZnO, and poly Acrylic acid-co-Maleic acid/ZnO,... 相似文献