Donor properties of the nitrone function in copper(II) complexes of some 2-hydroxy-1-naphthylnitrones

Summary Copper(II) complexes of the type CuL₂, 2H₂O and CuL₂. Py where L=-(2-hydroxy-1-naphthyl)-N-R-nitrone (R= methyl, phenyl and variously substituted phenyls) have been isolated and characterised. They have normal magnetic moments. Their ligand field spectra indicate an octahedral geometry for the dihydrates and a five-coordinate environment for the pyridine adducts. Increased (C=N) and considerably decreased (N-O) frequencies in these complexes reveal the presence of - and -interactions of the ligand with copper through nitrone oxygen. The effect of pyridine adduct formation is to increase the Cu-O -interaction.     

Pd-Ti and Pd-Co-Au electrocatalysts as a replacement for platinum for oxygen reduction in proton exchange membrane fuel cells

Fuel cells are appealing for a variety of energy needs, but the high materials and manufacturing costs have hampered their commercialization. The limited availability and the high cost of the currently used platinum catalysts, for example, pose a serious problem in their practical application. We report here non-platinum electrocatalyst systems, such as Pd-Co-Au and Pd-Ti, that are proposed from simple thermodynamic guidelines and selected by a rapid screening technique, which show electrochemical performance in proton exchange membrane fuel cells (PEMFC) similar to that found with commercial platinum catalysts. This finding opens up a new avenue to develop potentially less expensive electrocatalysts.     

NMR spectrum of benzo[b]furan in a nematic phase

The proton NMR spectrum of benzo[b]furan has been investigated in the nematic phase of a liquid crystal. Dipolar couplings obtained from the spectral analysis have been used to derive the interproton distance ratios. The phenyl ring geometry differs from that in benzo[b]thiophene. The deviations have been explained in terms of bond polarization effects.     

Multicomponent domino protocol for the stereoselective synthesis of novel pyrrolo[3,2-c]quinolinone hybrid heterocycles

A series of structurally intriguing novel pyrrolo[3,2-c]quinolinone heterocyclic hybrids have been synthesized for the first time via a one-pot multicomponent domino reaction sequence that involves a 1,3-dipolar cycloaddition and two subsequent annulation steps. Baylis-Hillman adducts derived from various substituted benzaldehyde and methyl acrylate in presence of DABCO were used as a dipolarophiles, while the 1,3-dipole components were azomethine ylides, formed in situ from isatin derivatives and l-phenylalanine. The reaction generated five new bonds, three new rings and four contiguous stereocenters, which were created with full diastereomeric control.     

Nonnegative solutions to reaction–diffusion system with cross-diffusion and nonstandard growth conditions

We establish the existence of nonnegative weak solutions to nonlinear reaction–diffusion system with cross-diffusion and nonstandard growth conditions subject to the homogeneous Neumann boundary conditions. We assume that the diffusion operators satisfy certain monotonicity condition and nonstandard growth conditions and prove that the existence of weak solutions using Galerkin's approximation technique.     

A Simple and Rapid Estimation of Major Bioactive Arnebin-1 from the Natural Dye Plant,Arnebia nobilis Reichb. f.

JPC – Journal of Planar Chromatography – Modern TLC - Arnebia nobilis has gained an increasing popularity for the recently recognized various pharmacological activities. The root part...     

Na2S–Carbon Nanotube Fabric Electrodes for Room‐Temperature Sodium–Sulfur Batteries

A unique sodium sulfide (Na₂S) cathode is developed, which will allow the use of sodium‐free anodes for room‐temperature sodium–sulfur (Na–S) batteries. To overcome the “inert” nature of the Na₂S, a special cathode structure is developed by spreading the multi‐walled carbon nanotube (MWCNT)‐wrapped Na₂S particles onto MWCNT fabrics. Spectroscopic and electrochemical analyses reveal a series of polysulfide intermediates involved in the charge/discharge of the cell. The Na–S battery prepared in full discharge state with the Na₂S/MWCNT cathode provides a remarkable capacity of 500 A h kg^?1 (based on sulfur mass) after 50 cycles.     

Crystal and molecular structure of trans-bis(dodecylamine) bis(dimethylglyoximato)cobalt(III) nitrite

An octahedral geometry for the molecule of the title complex with very slight distortions around Co(III) is confirmed by single-crystal X-ray diffraction study. The molecular structure of the complex has been shown to contain two dodecylamine moieties in the trans orientations, two N-bonded dimethylglyoximato (DMG) groups and an uncoordinated nitrite ion.     

“Metal-free” synthesis of 1,2,3-triazoles via tandem azidation,intramolecular [3+2]-cycloaddition and aromatization of ethyl acrylate derivatives

An efficient “one-pot” method for the synthesis of substituted 1,2,3-triazole derivatives in excellent yields as single regioisomer is reported. The key transformation involves an atom-efficient tandem azidation, intramolecular [3+2]-cycloaddition and aromatization of acrylate derivatives on treatment with NaN₃ in DMF under mild conditions.