Global Reactivity of Heterostructure Armchair BC2N‐(4,4) Nanotubes: A Density Functional Theory Investigation

Electronic structures of three types of heterostructure armchair BC₂N nanotube besides armchair (4,4)CNT and (4,4)BNNT were calculated by the B3LYP method of density functional theory. The reactivities of nanotubes were discussed by means of obtained vertical ionization potentials and electron affinity potentials. The corresponding electrophilicity values are well correlated with those obtained from the HOMO and LUMO energies of the nanotubes. The good linear correlation found between ω(I,A) and ω(H,L) allows to confirm the use of the easily available B3LYP/6‐31G(d) HOMO and LUMO energies to obtain reasonable values of the global electrophilicity index of nanotubes at a lower computational cost. © 2013 Wiley Periodicals, Inc. Heteroatom Chem 24:168–173, 2013; View this article online at wileyonlinelibrary.com . DOI 10.1002/hc.21078     

Highly Regioselective and Diastereoselective,One‐Pot,Four‐Component Synthesis of Novel Spiroindenoquinoxalineindolizidine Derivatives

A one‐pot, four‐component procedure for the synthesis of novel spiroindenoquinoxalineindolizidines with high regioselectivity and diastereoselectivity from the 1,3‐dipolar cycloaddition of azomethine ylides, generated from indenoquinoxalines and pipecolinic acid, and chalcones is described. The reaction occurs under reflux of ethanol as a green solvent and in the absence of any catalyst. The cycloadducts are obtained purely without future purification. The regiochemistry and stereochemistry of resultant cycloadducts have been determined by several 2D‐NMR spectroscopic techniques and X‐ray single crystal diffraction.     

Synthesis of new 2-substituted pyrazolo[5,1-b][1,3]oxazoles via Sonogashira coupling reactions in water

New 2-substituted pyrazolo[5,1-b][1,3]oxazoles are synthesized through the Sonogashira coupling reaction of 2-iodomethyl-6-methylpyrazolo[5,1-b][1,3]oxazole with terminal alkynes in the presence of a palladium catalyst. This process is carried out in the absence of any copper salt, and provides an eco-friendly and efficient method for the synthesis of the products in water in good-to-high yields. Some of the compounds synthesized were screened for their in vitro anti-oxidant activity using the DPPH (2,2-diphenyl-2-picrylhydrazyl) assays.     

Chiral bisoxazoline ligands with a biphenyl backbone: development and application in catalytic asymmetric allylic oxidation of cycloolefins

A simple and efficient method for the synthesis of chiral biphenylbisoxazoline ligands was developed. The bishydroxylamide precursors of ligands showed a dynamic atropselective resolution effect in the crystallization process. When biphenylbisoxazoline ligands were coordinated to tetrakis(acetonitrile)copper(I) hexafluorophosphate, it resulted in the formation of only a single diastereomer complex (S,aS,S), which behaved as a catalyst for the enantioselective allylic oxidation of cycloolefins. The enantioselectivity, yield, and rate of this reaction were optimized under different conditions, such as a change of solvents, temperature, and additives and also using various copper salts. The use of SBA-15 mesoporous silica as an additive played a crucial role in increasing the efficiency of the reaction.     

Three‐component synthesis of spiro[indoline‐3,5′‐pyrimido[4,5‐b]quinoline]‐triones in water

A one‐pot, three‐component method for the efficient and simple synthesis of novel 2′‐amino‐8′,9′‐dihydro‐3′H‐spiro[indoline‐3,5′‐pyrimido[4,5‐b]quinoline]‐2,4′,6′(7′H,10′H)‐trione derivatives in aqueous media is reported. J. Heterocyclic Chem., (2011).     

Multi-criteria supplier selection problem with fuzzy demand: a newsvendor model

Computational Management Science - In sourcing decisions, a buyer encounters three main issues. The first issue is the demand uncertainty that leads the buyer to find the optimal inventory level...     

Iron Oxide Nanoparticles: Biosynthesis,Magnetic Behavior,Cytotoxic Effect

Iron oxide nanoparticles have attracted much attention because of their superparamagnetic properties and their potential applications in many fields such as magnetic storage devices, catalysis, sensors, superparamagnetic relaxometry (SPMR), and high-sensitivity biomolecule magnetic resonance imaging (MRI) for medical diagnosis and therapeutics. In this study, iron oxide nanoparticles (Fe₂O₃ NPs) have been synthesized using a taranjabin (camelthorn or persian manna) aqueous solution. The synthesized Fe₂O₃ NPs were identified through powder X-ray diffraction (PXRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR), field energy scanning electron microscopy (FESEM), transmission electron microscopy (TEM), energy-dispersive spectroscopy (EDX), vibrating-sample magnetometer (VSM) and Raman technics. The results show that the nanoparticles have a hexagonal structure with 20 to 60 nm in size. The cytotoxic effect of the synthesized nanoparticles has been tested upon application against lung cancer cell (A549) lines. It was found that there is no cytotoxic activity at lower concentrations of 200 μg/mL. The ability of the synthesized nanoparticles for lead removal in wastewaters was tested. Results show that highest concentration of adsorbent (50 mg/L) has maximum removal efficiency (96.73 %). So, synthesized Fe₂O₃ NPs can be a good candidate to use as heavy metals cleaner from contaminated waters.     

Controlled elitist multi-objective genetic algorithm joined with neural network to study the effects of nano-clay percentage on cell size and polymer foams density of PVC/clay nanocomposites

The parameters of foaming and nano-clay percentage on the density of polymer foam and cell size with the PVC field is studied. Cell size and density have a significant impact on the strength of foam and its insulation (including sounds and thermal insulation). By optimizing cell size and density, foam can be produced with the best mechanical properties. In foaming process of the nanocomposite samples by mass method, the design variables (input parameters) are foaming time and temperature and MMT content. The controlled elitist multi-objective GA is applied to minimize both the foam density and the cell size. To that end, the population size and the Pareto fraction are selected as 100 and 0.5, respectively. The noninferior solution obtained by the controlled elitist multi-objective GA is illustrated. When both the MMT and the temperature are high, the resulting foam does not have ideal characteristics.

     

Designing chiral amido-oxazolines as new chelating ligands devoted to direct Cu-catalyzed oxidation of allylic CH bonds in cyclic olefins

A new type of amido-oxazoline ligands was conveniently synthesized from inexpensive and commercially available materials in high yields and enantiomeric excesses. The corresponding chiral copper complexes with this class of ligands [C₂ symmetric S,S-bis(amido-oxazoline-Cu(II) complex] were synthesized accordingly. The ORTEP diagram of ligand 6a and complex 6a-copper were compared and characterization of the complex confirmed the involvement of both dentate parts of the ligands, the oxygen and nitrogen atoms, in complexation with copper. The utilization of this amido-oxazoline ligands in the copper-catalyzed enantioselective esterification of allylic CH bonds of cyclic olefins with tert-butyl-4-nitrobenzoperoxoate resulted in the highest activities, yields (up to 95%) and enantioselectivities (up to 96%) in the presence of HZSM-5 zeolite. These new findings highlight the protocol as one of the most attractive and useful methods for the oxidation of the asymmetric allylic CH bond of cycloalkenes compared to other methodologies reported in the literature.     

Breakup of elliptical liquid jets in gaseous crossflows at low Weber numbers

Journal of Visualization - Breakup of circular and elliptical liquid jets in subsonic gaseous crossflows is experimentally studied using shadowgraph technique. The experiments are performed at...