785 research outputs found

    Die Bildung von Fluorisocyanat (F—NCO) in Argonmatrix

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    Matrix samples of F-CO-N3, and X-CO-NF2 (X = H, NF2, CF3) were photolyzed by mercury arc light and the new infrared bands at 2172, 861, 695, 646, 529 cm-1 assigned to the F-NCO molecule. 15N isotopic substitution confirmed the assignment of the IR bands of the new compound

    Total phenols, flavonoids, anthocyanins, ascorbic acid contents and antioxidant activity of Rhamnus kurdica Boiss for flower and leaves in flowering and pre-flowering stages

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    The antioxidant capability, total phenol, total flavonoid, anthocyanins, ascorbic acid contents, and reducing power contents of polar and non-polar extracts for flower and leaves in two stages of growth for Rhamnus kurdica Boiss in flowering were evaluated in this work. The polar extraction of flower of R. kurdica Boiss had a higher total phenolic content as well as antioxidant activity compared to that of the other subfractions of flower and leaves in the different stages. Antioxidant activities of the samples were determined by three various testing systems namely 2, 2-diphenyl-1-picrylhydrazyl (DPPH),  b-carotene/linoleic acid and reducing power assay. In DPPH system, the highest radical scavenging activity was seen by the polar subfraction in flowers of methanol extract [21.04±1.35 (μg/ml)]. Our findings demonstrate that the methanolic extracts of R. kurdica Boiss may be suggested as a new potential source of natural antioxidant.Keywords: Rhamnus kurdica Boiss, antioxidant, total phenolics, flaAfrican Journal of Biotechnology, Vol. 13(10), pp. 1131-1135, 5 March, 201

    Cloud Point Extraction and Spectrophotometric Determination of Uranium (VI) in Water Samples after Mixed Micelle-Mediated Extraction Using Chromotrope 2R as Complexing Agent

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    A rapid, selective and sensitive method for the preconcentration and determination of uranium (VI) by cloud point extraction (CPE) was developed. The method was based on the color reaction of 5.00 ng mL−1 uranium (VI) with 1.5×10−4 mol L−1 of chromotrope 2R in the presence of 0.015 mol L−1 potassi-um iodide at pH 8 in HEPES buffer and mixed micelle-mediated extraction of complex. The mixture of a nonionic surfactant (0.2 % (v/v) of (Triton X-114) and a cationic (2.0×10−4 mol L−1 of CTAB) was utilized as a suitable micellar medium for preconcentration and extraction of uranium (VI) complexes. Effect of extraction and reaction parameters was studied and optimum parameters were established. The analytical characteristics of the method (e.g. linear range, limit of detection, preconcentration and improvement factors) were obtained. Linearity was obeyed in the range of 0.2−10 ng mL−1 of uranium (VI) with a detection limit of 0.035 ng mL−1. The diverse ion effect of some anions and cations on the extraction efficiency of target ions was tested. The proposed method was successfully applied for the determination of uranium (VI) in various water samples. (doi: 10.5562/cca1922

    Synthesis & Spectral Characterization of Some New Carbacylamidophosphate Derivatives. Crystal Structures of CCl3C(O)NHP(O)[NH(C5H9)]2 and CH3C6H4C(O)NHP(O)[NH(C5H9)]2

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    Full Title: Synthesis and Spectral Characterization of Some New Carbacylamidophosphate Derivatives. Crystal Structures of CCl3C(O)NHP(O)[NH(C5H9)]2 and CH3C6H4C(O)NHP(O)[NH(C5H9)]2Some new carbacylamidophosphate derivatives with the general formula RC(O)NHP(O)[NH(C5H9)]2: (R=CCl3), 1a; (R=CHCl2), 2a; (R=CH2Cl), 3a; (R=CF3), 4a; (R=C6H5), 1b; (R=p-Cl-C6H4), 2b; (R=p-Br-C6H4), 3b; (R=p-Me-C6H4), 4b; were synthesized and characterized by 1H, 13C, 31PNMRand IR spectroscopy and elemental analysis. The crystalline solids of 1a and 4b were studied bysingle crystal X-ray diffraction analysis. The dimeric aggregate and the centrosymmetric dimer formed via intermolecular N-H....O=P and N-H....O=C hydrogen bonds in 1a and 4b, respectively. In all the synthesized molecules, similar spectral patterns were obtained in the 13C NMR spectra for carbon atoms of cyclic amines with 2J PNC = 0 and 3JPNC ranging from 4 to 6 Hz.KEYWORDS: Carbacylamidophosphates, hydrogen bonds, IR spectroscopy, NMR spectroscopy

    4-(N-Propan-2-ylcarbamo­yl)pyridinium perchlorate

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    In the title compound, C9H13N2O+·ClO4 −, the dihedral angle between the planes of the amide group and the pyridinium fragment is 34.11 (14)°. In the crystal, the cations are connected by N—H⋯O hydrogen bonds between the amide groups into chains extended along the a axis. Hydrogen bonds between the pyridinium N—H group and the perchlorate anions organize the chains into a two-dimensional network

    N-[Bis(dimethyl­amino)phosphinoyl]-2,2,2-trichloro­acetamide

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    In the title compound, C6H13Cl3N3O2P or CCl3C(O)NHP(O)(N(CH3)2), the phosphinoyl group is synclinal to the carbonyl group and acts as an acceptor for an inter­molecular N—H⋯O hydrogen bond from the amide group as the donor

    N,N′-Di-tert-butyl-N′′-(2,6-difluoro­benzo­yl)phospho­ric triamide

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    In the title compound, C15H24F2N3O2P, the phosphoryl and carbonyl groups adopt anti positions relative to each other. The P atom is in a tetra­hedral coordination environment and the environment of each N atom is essentially planar. In the crystal, adjacent mol­ecules are linked via N—H⋯O=P and N—H⋯O=C hydrogen bonds into an extended chain parallel to the a axis. The crystal studied was a non-merohedral twin with a minor twin component of 36.4 (1)%

    N,N′-Dibenzyl-N,N′-dimethyl-N′′-(p-tol­yl)phospho­ric triamide

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    The asymmetric unit of the title compound, C23H28N3OP, contains two independent mol­ecules with significant conformational differences. For example, the torsion angles N—C—C—C involving the N-benzyl moieties are 57.3 (7) and 11.6 (8)° in one mol­ecule and 76.5 (7) and 97.4 (7)° in the other. In each mol­ecule, the P atom exhibits a distorted tetra­hedral conformation [the bond angles at P are in the ranges 104.7 (2)–115.2 (2) and 105.1 (2)–115.1 (2)° in the two molecules], and the phosphoryl group and the N—H group adopt an anti orientation with respect to one another. In the crystal, mol­ecules are linked via N—H⋯O(P) hydrogen bonds, forming a chain parallel to the a axis
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