Electrochemical Characteristics of “Polyaniline” Cathodes and Anodes in Aqueous Electrolytes

The quinoid-benzenoid-diimine form, (=(C₆H₄)=N-(C₆H₄)-N=)_x of “polyaniline” shows excellent cathode characteristics including recyclability when used in conjunction with a zinc anode in an aqueous electrolyte of (l. 0M ZnCl₂ + 0. 5M NH₄Cl) having a pH of ～ 4. The reduced form of this material, (-(C₆H₄)-N(H)-(C₆H₄)-N(H)-)_x can be used as an anode in conjunction with a Pb0₂ cathode in an aqueous 0.5M Pb(BF₄)₂ electrolyte.     

Spectral and Mechanistic Investigation of Oxidation of Rizatriptan by Silver Third Periodate Complex in Aqueous Alkaline Medium

The oxidation of Rizatriptan by diperiodatoargentate(III) has been studied by spectrophotometry at neutral pH. The kinetics of the reaction of Rizatriptan has been shown to principle of non-complementary oxidation steps. The initial step involves the deprotonated of the diperiodatoargentate(III) with the alkali; this rearranges during the displacement of a ligand to give free periodate and takes up another ligand monoperiodateargentate(III), combines with a substrate to endow with an intermediate complex which decomposes within a slow step to provide the final product in the following step with a first-order rate constant. The main product was identified by spot test, Fourier- transform infrared spectroscopy, Nuclear magnetic resonance and Liquid chromatography-mass spectrometry spectrum. A conceivable mechanism including pre equilibrium of adducts development between the complex and reductant was planned from the kinetics study. The rate conditions got from system can clarify all exploratory phenomena, and the activation parameters alongside rate constants of the rate determining step were ascertained.     

Profiling primaquine metabolites in primary human hepatocytes using UHPLC‐QTOF‐MS with 13C stable isotope labeling

Therapeutic efficiency and hemolytic toxicity of primaquine (PQ), the only drug available for radical cure of relapsing vivax malaria are believed to be mediated by its metabolites. However, identification of these metabolites has remained a major challenge apparently due to low quantities and their reactive nature. Drug candidates labeled with stable isotopes afford convenient tools for tracking drug‐derived metabolites in complex matrices by liquid chromatography‐tandem mass spectrometry (LC‐MS‐MS) and filtering for masses with twin peaks attributable to the label. This study was undertaken to identify metabolites of PQ from an in vitro incubation of a 1:1 w/w mixture of ¹³C₆‐PQ/PQ with primary human hepatocytes. Acquity ultra‐performance LC (UHPLC) was integrated with QTOF‐MS to combine the efficiency of separation with high sensitivity, selectivity of detection and accurate mass determination. UHPLC retention time, twin mass peaks with difference of 6 (originating from ¹³C₆‐PQ/PQ), and MS‐MS fragmentation pattern were used for phenotyping. Besides carboxy‐PQ (cPQ), formed by oxidative deamination of PQ to an aldehyde and subsequent oxidation, several other metabolites were identified: including PQ alcohol, predictably generated by oxidative deamination of PQ to an aldehyde and subsequent reduction, its acetate and the alcohol's glucuronide conjugate. Trace amounts of quinone‐imine metabolites of PQ and cPQ were also detected which may be generated by hydroxylation of the PQ/cPQ quinoline ring at the 5‐position and subsequent oxidation. These findings shed additional light on the human hepatic metabolism of PQ, and the method can be applied for identification of reactive PQ metabolites generated in vivo in preclinical and clinical studies. Copyright © 2013 John Wiley & Sons, Ltd.     

4-hydroxy-2H-1,2-benzothiazine-3-carbohydrazide 1,1-dioxide-oxalohydrazide (1:1): X-ray structure and DFT calculations

The title compound, 4-hydroxy-2H-1,2-benzothiazine-3-carbohydrazide 1,1-dioxide-oxalohydrazide (1:1), is determined using X-ray diffraction techniques and the molecular structure is also optimized at the B3LYP/6-31G(d,p) level using density functional theory (DFT). The asymmetric unit consists of four independent molecules. The oxalohydrazide molecules have the centre of symmetry at the mid-point of the central C-C bond. Each thiazine ring adopts a half-chair conformation. Intermolecular C-H...O, N-H...O and N-H...N hydrogen bonds produce R ₂ ² (10), R ₂ ² (13), R ₃ ³ (12) and R ₃ ³ (15) rings, which lead to one-dimensional polymeric chains. An extensive three-dimensional supramolecular network of N-H...N, N-H...O, C-H...O and O-H...O hydrogen bonds is responsible for crystal structure stabilization.     

Sol–gel synthesis and characterization of conducting polythiophene/tin phosphate nano tetrapod composite cation-exchanger and its application as Hg(II) selective membrane electrode

Nano tetrapod based on conducting polythiophene (PTh) and tin-phosphate (SnP) were synthesized by in situ chemical oxidative polymerization. The morphology of the resulting polythiophene tinphosphate composite was characterized by elemental analysis, fourier transform infrared spectroscopy, thermogravimetric analysis, powder X-ray diffraction, scanning electron microscopy and transmission electron microscopy. The physico-chemical characterization carried out on the composite showed that SnP was modified by conducting PTh with an enhancement of various properties. On the basis of highest distribution coefficient values for Hg(II), the composite was also used for the preparation of Hg(II) selective membrane electrode. The electrode showed working concentration range of 1 × 10^?1 to 1 × 10^?7 with Nernstian slope of 29.29 mV per decade change in concentration and the electrode may be used for wide working pH range of 4–8 having quick response time about 23 s. The life of electrode is 4 months without any notable drift in potential.