An ambient temperature Sonogashira cross-coupling protocol using 4-aminobenzoic acid as promoter under copper and amine free conditions

A new methodology has been developed based on Pd(OAc)₂ and 4-aminobenzoic acid catalytic system for the Sonogashira cross-coupling reaction at ambient temperature under copper and amine free conditions. The newly developed catalytic system is conveniently applicable to the aryl iodides and terminal acetylenes. The catalytic system is much efficient because of the use of easily available and low cost additive.     

Effect of variable viscosity on boundary layer flow along a continuously moving plate with variable surface temperature

Flow of an incompressible viscous fluid past a continuously moving semi-infinite plate is studied by taking into account variable viscosity and variable temperature. Velocity and temperature profiles are shown graphically whereas the numerical values of the skin-friction and the rate of heat transfer are listed in a table. The effect of different parameters on the flow field is discussed.     

Acetanilide palladacycle: an efficient catalyst for room‐temperature Suzuki–Miyaura cross‐coupling reaction

The catalytic activity of three acetanilide palladacycles derived from easily accessible and commercially available acetanilide derivatives, viz. N‐phenylacetamide ( L1 ), N‐(4‐chlorophenyl)acetamide ( L2 ) and N‐(4‐methylphenyl)acetamide ( L3 ) has been examined in Pd‐catalyzed Suzuki–Miyaura reaction of arylboronic acid with aryl bromides at room temperature. The complex 1L3 exhibited efficient activity in the Suzuki–Miyaura reaction (up to 99% isolated yield) under mild reaction conditions. Copyright © 2014 John Wiley & Sons, Ltd.     

Protecting group directed stereoselective reduction of an epi-inosose: efficient synthesis of epi-inositol

A facile and high yielding synthesis of epi-inositol via stereoselective reduction of a pentaprotected epi-inosose is reported. Extent of stereoselectivity during the hydride reduction appears to depend on the ability of the substrate to complex with metal ions in the reducing agent.     

Synthesis and Thermal Decomposition of Cobalt(II) bis (Tartrato) Cobaltate(II) Trihydrate

The paper describes the synthesis and characterization of cobalt(II) bis (tartrato) cobaltate(II) trihydrate Co[Co[C₄O₆H₄)₂]·3H₂O. The complex was characterized on the basis of elemental analysis, infrared, electronic, e.s.r. spectra and X-ray powder diffraction studies. The thermal decomposition of the complex led to a mixture of Co₂O₃and Co₃O₄in air at about 400°C, whereas in nitrogen it was decomposed to a mixture of CoO and C at about 384°C. A tentative reaction mechanism is suggested for the thermal decomposition of the complex in air and nitrogen. This revised version was published online in July 2006 with corrections to the Cover Date.     

Tetrakis(μ‐benzoato‐κ2O:O)bis{[4‐(dimethylamino)pyridine‐κN1]copper(II)}

The title compound, [Cu₂(C₇H₅O₂)₄(C₇H₁₀N₂)₂], is a crystallographically centrosymmetric binuclear complex, with Cu atoms [Cu...Cu = 2.6982 (4) Å] bridged by four benzoate ligands. Each of the Cu atoms in this bunuclear copper(II) acetate hydrate analogue is present in an approximately square‐pyramidal environment, with four O atoms in a plane and the pyridine N atom at the apical site. Selected geometric parameters are compared with values for related tetrabenzoate complexes of copper(II).     

New oxo-bridged dinuclear peroxotungsten(VI) complexes: Synthesis, stability and activity in bromoperoxidation

Two new dinuclear oxo-bridged peroxo complexes of tungsten with coordinated dipeptides of the type, Na₂[W₂O₃(O₂)₄(glycyl-glycine)₂] · 3H₂O (1) and Na₂[W₂O₃(O₂)₄(glycyl-leucine)₂] · 3H₂O (2) have been synthesized from the reaction of H₂WO₄, 30% H₂O₂ and the respective dipeptide at pH ca. 2.5. Synthesis of the compounds, in addition to pH, is sensitive to reaction temperature and concentrations of the components. The compounds were characterized by elemental analysis, spectral and physico-chemical methods including thermal analysis. In the dimeric complexes the two W(VI) centres with edge bound peroxo groups are bridged by an oxo group. The dipeptides occurring as zwitterions bind the metal centers through O (carboxylate) atoms leading to hepta co-ordination around each W(VI). Thermal stability of the compounds as well as their stability in solution were determined. The compounds are highly stable toward decomposition in solutions of acidic as well as physiological pH. These compounds, besides another similar dimeric compound Na₂[W₂O₃(O₂)₄(cystine)] · 4H₂O (3) efficiently oxidized bromide to a bromination competent intermediate in phosphate buffer at physiological pH, a reaction in which only two of the peroxide groups of the complex species were found to be active. The complexes could also mediate bromination of organic substrate in aqueous-organic media.     

Supply-chain coordination model with insufficient production capacity and option for outsourcing

In this paper, a mathematical model is developed to analyze the situation of lost sales from the supply-chain coordination perspective. In a two-stage supply chain, the supplier’s production capacity is less than the annual demand of the retailer. The supplier may recover the deficit by procuring the same from an external source at a certain price and then supplying it back to the retailer. Here, the conditions have been derived when the practice of external procurement may be a viable solution to enhance the profits of both the supplier and retailer in a coordinated approach. A numerical example is carried out to illustrate the efficacy of the developed model and the procedure developed for solving the problem.     

Mesometeorological observation of physical properties in a typical wave cyclone family in western oregon

Zusammenfassung Es wird über die Untersuchung einer Zyklonenperiode in West-Oregon berichtet, die in koordinierter Weise konventionelle synoptische, luftelektrische und Radarbeobachtungen verwendet. Derartige kombinierte Analysen dürften geeignet sein, mesometeorologische Probleme, wie zum Beispiel die Kartierung der örtlichen Niederschlagsverteilung, zu lösen.     

Studies of nanocomposite of Polyaniline with gold nanoparticles and Schottky junction with aluminium for electrical and CO2 gas sensing properties

Gold nanocomposite of Polyaniline was prepared by chemical synthesis method and its thin film was made by drop casting. The Schottky junction of thin film was fabricated with aluminium metal. TGA analysis of the sample showed good stability. Current density-voltage characteristics of the junction showed good rectifying nature. The diode ideality factor is greater than unity. The junction showed good sensitivity to CO₂ gas with decrease of forward current. The response time of the junction to CO₂ showed good repeatability and recovery time is about 52 s.