Study of photon-induced L3 vacancy alignment for elements La to U

Alignment of photon-induced L₃ vacancies is studied in rare earth and highZ elements at energies of experimental interest, near thresholds to 60 keV, under nonrelativistic dipole approximation. Numerical calculations of the matrix element are undertaken to produce theoretical data for comparison with the experimental findings. The A₂ values being s>0.1 at photoelectron energies <20 keV are certainly higher than 5–8% uncertainties quoted in experimental results. Present findings are from a very basic model, hydrogen-like and can further be treated as reference to observe the impact of screening, relativistic, multipole and retardation corrections to the model     

Amperometric determination of calcium as selenite

Summary An amperometric titration of calcium with selenite is described. Barium, strontium, and other cations forming insoluble selenites interfere, but magnesium does not. The method is rapid and suitable for routine analysis, the error being less than 10 parts per 1000 over the range 50 to 70 mg of calcium.

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Zusammenfassung Ein amperometrisches Titrationsverfahren für Calcium mit Selenit wurde beschrieben. Barium, Strontium und andere Kationen, die unlösliche Selenite bilden, stören, nur Magnesium nicht. Das Verfahren ist rasch und für Routineanalysen geeignet. Im Bereich zwischen 50 und 70 mg Calcium ist der Fehler geringer als 1% relativ.

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Résumé On décrit un titrage ampérométrique du calcium par l'ion sélénite. Le baryum, le strontium et les autres cations formant des sélénites insolubles interfèrent, excepté le magnésium. La méthode est rapide et convient à l'analyse en série, l'erreur étant inférieure à 10 parties pour 1000 dans le domaine de 50–70 mg de calcium.

     

1,1,1,1-Tetrakis(o-fluorophenylamino)silane tris[titanium(IV) chloride]. Evidence for a new titanium cation [Ti2Cl7]+

Si(NHC₆H₄F-o)₄ · 3TiCl₄ (1) has been obtained from the disproportionation of (CF₃CH₂O)₃SiNHC₆H₄F-o and TiCl₄ in petroleum ether (40–60 °C) at –10 °C. The analytical (elemental analysis, molar conductance) and spectral (i.r., ¹H- and ¹⁹F-n.m.r.) data suggested that (1) behaves as [Si(NHC₆H₄F-o)₄ · Ti₂Cl₇]⁺ [TiCl₅]^–. The presence of these ions has been confirmed by characterising the products of metathetical reactions of (1) with R₄NX (R = Bu and Et; X = I and Br) and with AgNO₃. The data suggest the presence of a new titanium cation [Ti₂Cl₇]⁺.     

Cobalt(II) complexes of new biomimetic polydentate amide ligands. A spectroscopic,thermal and potentiometric study

Complexes of Co^II with N,N-bis-(3-carboxy-1-oxopropanyl)-1,2-ethylenediamine(L₁), N,N-bis-(3-carboxy-1-oxopropanyl)-1,2-phenylenediamine(L₂), N,N-bis-(2-carboxy-1-oxophenelenyl)-1,2-phenylenediamine(L₃) and N,N-bis-(3-carboxy-1-oxoprop-2-enyl)-1,2-phenylenediamine(L₄) have been prepared and characterized by elemental analysis, vibrational spectra, magnetic susceptibility measurements, electronic spectra and thermal studies. Stability constants of the complexes have been evaluated potentiometrically. Vibrational spectra indicate coordination of amide and carboxylate oxygens of the ligands along with two water molecules giving a MO₆ weak field octahedral chromophore. Electronic spectra support octahedral geometry around Co^II. The [Co(L₁)-(H₂O)₂] · 2H₂O complex has the maximum activation energy and [Co(L₃)(H₂O)₂] complex has the minimum activation energy. The order of stability constants of the Co^II complexes with various ligands is due to their -donor abilities.     

Investigation of nu(N-H) and nu(C-N) stretching modes of propylamine (C3H7NH2) in a binary system C3H7NH2 + CH3OH via concentration dependent Raman study and ab initio calculations

Raman spectra of propylamine (C3H7NH2) and its binary mixtures, C3H7NH2 + CH3OH with varying mole fractions of the reference system, C3H7NH2, C were recorded in two widely apart wavenumber regions, 3100-3600 cm(-1) and 1225-1325 cm(-1). In the former region, the two Raman bands at approximately 3305 and approximately 3326 cm(-1), obtained after the line shape analysis, which were assigned to symmetric nu(N-H) and anti-symmetric nu(N-H) stretching modes, respectively, show a downshift upon dilution. However, whereas the nu(N-H) anti-symmetric mode shows a shift of 18.6 cm(-1), the nu(N-H) symmetric mode shows a much smaller shift (5.7 cm(-1)) between neat liquid and high dilution, C = 0.1. This aspect has been explained using the optimized geometries calculated employing ab initio theory (MP2 level) for the neat C3H7NH2 and its different hydrogen-bonded complexes. The linewidth versus concentration plot for the nu(N-H) anti-symmetric stretching mode, however exhibits a distinct maxima at C = 0.4, which has been explained as a slight departure from the concentration fluctuation model. In the latter region, a symmetric peak is observed, which corresponds to nu(C-N) stretching mode, which shows an upshift upon dilution and an almost linear concentration dependence. This has also been explained in terms of the parameters obtained from the optimized geometries of the different hydrogen-bonded complexes.     

Sensitive and selective methods for determination of antipsychotic drug olanzapine in pharmaceuticals

Two simple and sensitive spectrophotometric methods have been developed for analysis of the antipsychotic drug olanzapine in pharmaceuticals. Method A is based on liberation of iodine by reaction between the drug and potassium iodate, followed by reaction with leuco crystal violet (LCV), the color of oxidized LCV being measured at 598 nm. Method B is based on oxidation of olanzapine with chloramine-T (CAT) in acidic medium, the unconsumed CAT being determined with rhodamine B, measuring the absorbance at 550 nm. Calibration graphs were linear over the ranges of 0.05–2.0 and 0.1–1.6 μg mL^?1 olanzapine for method A and B, respectively. The molar absorptivity, Sandell’s sensitivity, detection limit, and quantitation limit were found to be 1.59 × 10⁵, 0.00132, 0.038, and 0.117, respectively, for method A and 0.953 × 10⁵, 0.00221, 0.064, and 0.192, respectively, for method B. The optimum conditions and other analytical parameters were evaluated. The proposed methods have been applied successfully for analysis of olanzapine in pure form and its dosage forms, and no interference was observed from common excipients present in pharmaceutical formulations.     

Synthesis of five-membered N-heterocycles using silver metal

The heterocyclic chemistry field has been revolutionized using transition metal catalyst in recent years. Various research groups have focused on the development of general protocols to achieve better functional group compatibilities and greater levels of molecular complexity under mild reaction conditions using easily available starting substrates. These methods afford many advantages as compared to alternative pathways involved in the synthesis of heterocyclic compounds. In this review article, we have concentrated on the synthesis of nitrogen-containing five-membered heterocylces in the presence of silver catalyst.     

Spectrophotometric analysis of trichloroethylene in various environmental and biological samples

A simple sensitive extractive spectrophotometric method for determination of trichloroethylene is proposed. Trichloroethylene is treated with pyridine to form glutaconic aldehyde by heterolytic cleavage of the pyridine ring. Glutaconic aldehyde is further coupled with 4-aminoacetanilide to form an orange–red dye which is extractable in 3-methyl-1-butanol. The extracted dye shows absorption maximum at 520 nm. The system obeys Beer’s law in the range of 0.05–0.8 μg mL^?1. Important analytical parameters such as time, temperature, reagent concentration, acidity etc. have been optimized for complete colour reaction. Sandell’s sensitivity and molar absorptivity for the system were found to be 0.001 μg cm^?2 and 1.2 × 10⁵ L mol^?1 cm^?1, respectively. The proposed method is satisfactorily applied to micro-level determination of trichloroethylene in various environmental and biological samples.     

A Retrospective Study on Applications of the Lindley Distribution

The need for efficient statistical models has increased with the flow of new data, which makes distribution theory a particularly interesting and attractive field. Here, we provide a thorough study of the applications of the Lindley distribution and its diverse generalizations. More precisely, we review some special applications in various areas, such as time series analysis, stress strength analysis, acceptance sampling plans and data analysis. We also conduct a comparative study between the Lindley distribution and some of its generalizations by using four real-life data sets.