A Novel Magnetic Polyethylene Glycol Nanocomposite based on Graphite Reinforcement Carbon Paste Electrode for Voltammetric Determination of Perindopril L-arginine

Journal of Analytical Chemistry - The present study reports the development of a magnetic polyethylene glycol nanocomposite based on graphite reinforcement carbon paste electrode for the sensitive...     

Synthesis of New Dibenzosulfide and Dibenzosulfoxide Macrocyclic Compounds

Some new dibenzosulfo, dibenzosulfoxo macrocyclic diamides are synthesized.     

Absorptiometric determination of sulphide ion

An absorptiometric method is described for sulphide ion, based on the green colour which is formed when sulphide ions are treated in ammoniacal solution with iron(III) and an excess of nitrilotriacetic acid. The recommended procedure can be applied from 1200 down to 8 ppm of sulphide and is interfered with seriously only by selenite from amongst seventeen other anions examined. The colour system is stabilized by an excess of sulphite. Suggestions are made about the nature of the colour body and its mechanism of production.     

Activity concentrations of 210Po in the soft parts of cockle (Anadara granosa)at Kuala Selangor, Malaysia

Polonium-210 has been measured in the soft parts of Anadara granosa purchased at Kuala Selangor, West Coast of Malaysia in August 2001, April 2002 and September 2002. It is shown that ²¹⁰Po is non-uniformly distributed within cockles of various sizes (i.e., 2.5, 3.0, 3.5 and 4.0 cm of shell length) and the concentration of ²¹⁰Po in the soft parts of cockle was significantly different (p<0.05) due to sampling date. The highest value was observed in the smallest cockle with a shell length of 2.5 cm (411.6±26.16 Bq/g dry wt.). It is clear that there is an allometric relationship between ²¹⁰Po activity concentration and individual cockle weight. This may reflect on the differences of metabolic rate and growth age of cockles. The mean activity concentration of ²¹⁰Po measured in Kuala Selangor filtered water were 1.75±0.17, 0.79±0.08 and 1.13±0.20 Bq/kg for August 2001, April 2002 and September 2002, respectively. The yield concentration factors for ²¹⁰Po in the soft parts of cockles varies from 27.3^. 10³ to 106.9^. 10³. This revised version was published online in July 2006 with corrections to the Cover Date.     

Titrimetric and spectrophotometric methods for the determination of cerium(IV) in aqueous solution

A titrimetric and spectrophotometric methods for cerium(IV) determination have worked out. The first method relies upon the treatment of cerium(IV) solution with an excessive amount of iodide; the liberated iodine is extracted into chloroform, then reduced to iodide. The latter is iodometrically determined after 6- or 36-fold amplification. The spectropho-tometric finish is based upon the reaction of the titled ion with iron(II), in the presence of hexacyanoferrate(II), to form an intense prussian blue color suitable for the trace determination of cerium(IV) ion.     

Metal complexes of a homopolymer system containing diethanolamine side group: synthesis and dielectrical behaviors

In this work, 4-diethanolaminomethyl styrene (DEAMSt) monomer was prepared by modification of 4-chloromethyl styrene with diethanolamine. The homopolymerization of styrene modificated was carried out by free radical polymerization method at 60?°C in presence of 1,4-dioxane and AIBN. The metal complexes were prepared by reaction of the homopolymer used as ligand P(DEAMSt)L^l and Ni(II), Co(II) metal ions in presence of ethanol and dilute NaOH at 65?°C for 48?h in pH 6.

The structure of modificated monomer, homopolymer used as ligand and polymer-metal complexes were characterized by (FT-IR), ¹H-NMR, ¹³C-NMR, Raman spectroscopy tecniques, elemental analysis, SEM, XRD and magnetic measurements. Their geometric structures according to magnetic measurements of Co(II) and Ni(II) complexes were estimated that have a tetrahedral structure. P(DEAMSt)L^l polymer has a transition state between amorphous and crystalline, whereas metal complexes (Co(II) and Ni(II) are with a large crystal structure. The molecular weight of P(DEAMSt)L¹ homopolymer was determined by gel permeation chromatography (GPC). The glass transition temperature (Tg) of homopolymer was measured by differantial scanning calorimeter (DSC). The thermal behaviors of both ligand and polymer-metal complexes were investigated by thermogravimetric analysis (TGA) and (DTA). The results obtained were compared with each other. Then, the dielectrical measurements (dielectric constant, dielectric loss and conductivity) of the ligand and polymer-metal complexes were investigated as a function of temperature and frequency. The activation energies (Ea) of the ligand and metal complexes were determined from the conductivity measurements.     

Triiron and Triruthenium Carbonyl Clusters Bearing Bridging Long Chain Diphosphine and Capping Chalcogenido Ligands

Treatment of Ru₃(CO)₁₂ with dpphSe₂ (dpph = 1,6-bis(diphenylphosphino)hexane) in refluxing toluene in the presence of Me₃NO afforded two new compounds, Ru₃(CO)₇(-CO)(₃-Se)(-dpph) (1) and Ru₃(CO)₇(₃-Se)₂(-dpph) (2). A similar reaction of Ru₃(CO)₁₂ with dpppeSe₂ (dpppe = 1,5-bis(diphenylphosphino)pentane) gave exclusively Ru₃(CO)₇(₃-Se)₂(-dpppe) (3). Treatment of Ru₃(CO)₁₂ with dpphS₂ and dpppeS₂ at 110°C in the presence of Me₃NO afforded Ru₃(CO)₇(₃-S)₂(-dpph) (4) and Ru₃(CO)₇(₃-S)₂(-dpppe) (5), respectively. Reactions of Fe₃(CO)₁₂ with dpphSe₂ and dpppeSe₂, under identical conditions, afforded Fe₃(CO)₇(₃-Se)₂(-dpph) (6) and Fe₃(CO)₇(₃-Se)₂(-dpppe) (7), respectively. Compounds 1–7 were characterized spectroscopically and the molecular structures of compounds 1–4 were determined by single crystal X-ray crystallography. The core of 1 contains an equilateral triangle of ruthenium atoms with one capping selenium, one bridging dpph, one doubly bridging carbonyl and seven terminal carbonyl ligands. Complexes 2–4 have a square-pyramidal structure with two metal and two chalcogenide atoms alternating in the basal plane and the third metal atom at the apex of the pyramid, and belong to the family of well-known nido clusters with seven skeletal electron pairs.     

Vinyl nosylates as partner in copper and silver co-catalyzed Sonogashira cross-coupling reactions

Vinyl nosylates, readily obtained from β-dicarbonyl derivatives, could be efficiently engaged in Sonogashira cross-coupling reactions, either cocatalyzed by copper or silver salts. The para-nitrobenzenesulfonate (nosylate) group allows this coupling to be performed under very mild conditions (room temperature). These new leaving group and mild conditions could be applied to the synthesis of acetylenic coumarinyl derivatives and to the total synthesis of an acetylenic monoterpene natural product, named cleviolide.     

Thermoelectric properties of n-type Bi2Te3 alloys produced by a combined process of magnetic pulsed compaction (MPC) and spark plasma sintering (SPS)

In this study, n-type 95 %Bi₂Te₃-5 %Bi₂Se₃ thermoelectric materials have been produced by a combined process of gas atomization with subsequent magnetic pulsed compaction and spark plasma sintering, and then we investigated the behavior of transport properties with sintering temperature. The microstructural observation was performed by optical microscopy and scanning electron microscopy. The crystal structures were analyzed by X-ray diffractometer. The mechanical properties were calculated by measuring the density and micro-Vickers hardness of the samples. It was found that with increasing sintering temperature the gaps between powder particles decreases and the grain sizes were coarsened. The mechanical properties shows higher values along the parallel direction compared to the perpendicular direction to the pressing. The transport properties of the thermoelectric material were investigated with variation of the sintering temperatures. The maximum power factor 1.7 × 10^?3 Wm^?1 K^?2 was measured at the sintering temperature of 450 °C.